A
PLASTERING
PLAIN & DECORATIVE
MILLAR
r
UNIV. OF CALIF. LIBRARY. LOS ANGELES
i
LIBRARY OF
ARCHITECTURE AND
ALLIED ARTS
Gift of
The Heirs of R. Geirmain Hubby, A. I. A,
r
WIV.
k.
PLASTERING
PLAIN AND DECORATIVE.
INDEX TO ADVERTISERS.
Adie, Patrick
Asbestos and Asbestic Co., Lt. (The)
Batsford, B. T.... Baxter, R., & Co. BicKLEY, Joseph
Cafferata & Co.
De Jong, F., & Co. Drew, W. G.
Ford, Peter, & Sons
Gilchrist, Alexr.
Hall, John Harbutt William HOBMAN, A. C. ^\'., & Co. Howe, John, & Co
Illustrated Carpenter and Builder (The)
Jones, Fred., & Co.
L.atto, a. F., & Co.
Mural and Decorations Syndicate, Lt. (The) Millar, W\
Nelson, Geo., Dale & Co., Lt. ...
Patent Indurated Stone Co., Lt. (The) ...
Robinson, Joseph, & Co., Lt. Rome, George, & Co. Rule, John
S.4LTER, Geo, & Co.
Subwealden Gypsum ( o., Lt. (The)
Tyzack, Samuel Wilson, J., & Son Young, B., & Co.
TAGE
VII.
I.
XVI. XIV.
VL
III.
XIII. XIII.
XIV.
XV.
XII. XII.
XIV.
II.
XV.
X.
XIV.
XI. XVI.
XIII. IX.
V. XI.
VI.
VIII. IV.
XV.
XIII.
X.
\
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'■' *%
NATIONAL T> ^ ^W^
ASSOCIATIONofOPERATIVEPlASTERERS v'l J f "J '' ,' ^' ruppoi
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Ace
PLASTERING
PLAIN AND DECORATIVE.
A PRACTICAL TREATISE ON THE ART & CRAFT OF PLASTERING AND MODELLING.
INCLUDING FULL DESCRIPTIONS OF THE VARIOUS TOOLS, MATERIALS, PROCESSES, AND APPLIANCES EMPLOYED; ALSO OF MOULDED OR "FINE" CONCRETE AS USED FOR FIREPROOF STAIRS AND FLOORS, PAVING, ARCHITECTURAL DRESSINGS, &c. &c.
TOGETHER WITH AN ACCOUNT OF
HISTORICAL PLASTERING IN ENGLAND, SCOTLAND. AND IRELAND,
ACCOMPANIED BY NUMEROUS EXAMPLES.
BY
WILLIAM MILLAR,
PLASTERER AND MODELLER.
WITH AN INTRODUCTORY CHAPTER ENTITLED "A GLIMPSE OF ITS HISTORY,"
Bv G. T. ROBINSON, Esq., F.S.A.
THE WHOLE FULLY ILLUSTRATED WITH FIFTY-TWO FULL PAGE PLATES, AND TWO HUNDRED AND THIRTY. ONE SMALLER ILLUSTRATIONS (comprising over Five Hundred Figures) IN THE TEXT.
LONDON: B. T. BATSFORD.
NEW YORK: TRUSLOVE, HANSON & COMBA, LTD.,
67 FIFTH AVENUE. 1899.
i
Ufbafi Planniag Utsarf
A PREFATORY NOTE.
>*<
MR MILLAR has asked me to say for him that which he finds somewhat difficult to say for himself, and I think the simplest way of doing this will be to explain in the fewest possible words, how and why we made each other's acquaintance and what came of it. In 189 1 I read a lecture on " Decorative Plaster Work " at the Society of Arts, a subject in which I felt much interest, and one on which I had previously written and spoken. To this lecture Mr Millar came, and shortly afterwards sought me, telling me of his craft-work, and of his proposed book on Plastering, upon which he had then been long engaged. For this he asked for such literary help as I could give him. I found in him a craftsman who delighted in his craft, and one who, whilst yet in his 'prentice days, finding that, unlike most other handicrafts, plastering had no text-book or manual, set before himself the ambition of writing one. Following his father's wholesome advice (himself a plasterer, and a descendant of a long line of plasterers), he set himself to "learn his trade first," but whilst doing this, he kept collecting facts, and laying the foundation of the work he has at length achieved. Fortunately he had, what is becom- ing in these versatile days, the 7'an- advantage of a rigorous apprenticeship, and bettered his instruction by learning more, and working through the United Kingdom, even extending the sphere of his labour to Paris. Keeping his eyes open, he acquired a very extended knowledge of the direct ways of his trade, and taking notes of all the processes he came in contact with, he accumulated an extensive craft knowledge in the byways of it. These he extended by well-directed reading, and better still by observation, and reasoning upon what he learnt ; inventing new methods, trying new materials, viewing both sides of the questions of the trade, now as workman and now as master, until he thoroughly fitted himself for the task he never lost sight of, and about 1880 commenced formulating his book. And now troubles came upon him — ill- health, misfortune, domestic afflictions, and last of all a fire, which not only bereft him of house and home, but burnt his treasured manuscripts and drawings, and all he had written for his book. But Mr Millar, like a true Scot, without repining at the inevitable, set to work again, re-wrote his manuscript and re-made his drawings. Even yet an envious fate pursued him, for after making arrangements for their publica- tion, and after they had been for many months in the hands of his intended publisher, that gentleman failed, without having made any progress with the production of the book.
vi Prefatory Note.
The present publisher havin_ij undertaken to bring his book before the world, Mr Millar has carefully gone through the manuscript again, altering it, adding to it, and bring- ing it quite up to date. As for me, I have simply revised it for the press, in fulfilment of a promise I made long ago, finding, however, no alteration needed in the technical portion. Only in the first chapter have I made anything beyond verbal alteration, and that as small a.^ possible, leaving Mr Millar to describe in his own language the pro- cesses he is so thoroughly familiar with. For tiie historical r<fstimd\\e had accumulated an immense amount of matter, from which I have freely drawn, supplementing it by other information learned from my own studies, and chronologically arranging both ; but the value of the work is entirely due to his own labours, and I heartily congratulate him on its final achievement after such arduous struggles. I wish it all the success his per- severance deserves and its thoroughness should command, and I trust that such success may encourage other craftsmen to write their own "shop knowledge" as intelligently and as intelligibly as Mr Millar has here done that of plaster work. To his own craft it is a life's legacy ; to the younger metnbers, it will be an invaluable te.xt-book ; to the elder ones, a permanent pleasure. To my own pro- fession, and to all others interested in so useful and so decorative a pursuit, it will prove a lasting book of constant reference.
GEO. T. ROBINSON.
London, 20//; February 1897.
AUTHOR'S PREFACE.
>»<
A S kindly set forth in the " Prefatory Note," by Mr G. T. Robinson, to whom I desire here to record my deep indebtedness and warmest thanks for much valu- able help and encouragement, the present volume is the outcome of a long-cherished idea pursued to its fulfilment. So far back as the time of my apprenticeship — when attending the classes of the Edinburgh School of Arts — the need of a practical book on Plastering and Modellino- was oreatlv felt. It was thougrht remarkable that although many books, varying in size and in degrees of merit, dealing with other branches of the building trades, were in use, no such book existed on this ancient and honourable craft, and I believe that this is the first complete and practical work published on the subject.
In preparing this work my aim and purpose has been to fill this long existing void by furnishing for the use of my brethren of the craft a practical treatise on the manufacture, use, and manipulation of all materials, and a description of the numerous processes employed by plasterers and modellers.
Although fortified by a life-long study of the subject, together with a most varied experience, I make no claim to literary ability, and would disarm my critics by reminding them of Pope's incontrovertible poetical axiom :
" ^Vhoever thinks a faultless work to see, Thinks what ne'er was, nor is, or e'er can be."
That this book may help to spread a knowledge of the means and methods of executing all kinds of work in plaster, and so cause a greater appreciation of it, and a desire tor its wider use, thus bringing about a true revival of the craft, to the benefit both of the employer and craftsman, is my earnest wish. Should this anticipation be realised, my reward will be in the consciousness that I have been the means of forwarding the study of my favourite art and craft.
viii Author ^ Preface.
To the above lines (written for the most part more than four years ago), I desire to aild. in justice to my pubUsher, that since he announced the publication of the book in 1895, I have thoroughly revised it, re-casting some parts, enlarging others, and intro- ducing descriptions of new materials and processes. This has occupied more time than at first seemed probable, and has caused the not inconsiderable delay that has occurred in its production, but which, it is hoped, may be more than atoned for by the greater completeness of the work. In conclusion, 1 have much pleasure in acknowledging the assistance afforded me by Mr l!radk-y Batsford, especially in helping me to add numerous valuable illustrations to those I had already drawn and collected.
WILLIAM MILLAR. London, Manh 1897.
NOTE TO THE SECOND EDITION.
T II. WE every reason to be gratified with the success achieved by my book, as shown by the sale of a large edition in less than two years, and the continued demand, to meet which a Second T'ldiiion has become necessary.
1 have carefully read the book through, and have made such small corrections anil alterations as appeared necessary. That it has defects I make no doubt, but it is satisfactorv to know that although it has been in use in laro-e numbers duringf nearly two years, none worthy of mention have been discovered in it either by its u.sers, or its critics. On the other hand, I have received a laree number of letters expressing the greatest satisfaction with it from fellow craftsmen, members of the architectural profession, and others.
Finally, 1 may mention that the Worshipful Company of Plai-sterers were good enough to send me not only a highly eulogistic letter, but also a handsome testimonial of their appreciation of my work.
W. M.
.'ifanh 1899.
CONTENTS.
>*<
CHAP. PAGE
LIST OF PLATES --------- xi
LIST OF ILLUSTRATIONS IN THE TEXT - - - ' - - xiii
INTRODUCTORY— "A GLIMPSE OF ITS HISTORY" fBv G. T. Robinson,
F.S.A.) ---------- I
I. HISTORICAL PLASTERING IN ENGLAND, SCOTLAND, AND IRELAND 24
II. MATERIALS ------...- 35
III. MATERIALS— Continued -..--.- 55
IV. LIME PLASTERING _-...--.- 89 V. DECORATIVE CEILINGS - - - - - - - 123
VI. RUNNING DIMINISHED AND CIRCULAR MOULDINGS - - - 148
VII. EXTERIOR PLASTERING - - - - - - - 181
VIII. MODELLING --.----.- 224
IX. MOULDING AND CASTING - - - - - - - 249
X. MODEL AND RUNNING MOULD MAKING - - - - - 290
XI. GELATINE MOULDING - - - - - - - - 317
XII. FIBROUS PLASTER WORK - - - - - - - 343
XIII. REVERSE MOULDING -------- 380
XIV. COMPOSITIONS --------- 393
XV. SCAGLIOLA - - - - - ' - - - - 407
XVI. FOREIGN PLASTER WORK - - - - - - - 420
XVII. TERRA COTTA --------- 450
XVIII. CONCRETE - . - 456
XIX. CONCRETE— Continued - - - - - - - - 485
XX. RUDIMENTARY GEOMETRY AND ARCHITECTURE - - - 517
XXI. TOOLS AND APPLIANCES - 537
APPENDIX - - - - - 555
INDEX ---------- 580
LIST OF PLATES.
>*<
PLATE
Frontispiece. I. Plaster Pavement at Tel-el- Amarna, Egypt, 1400 b.c. following page 34
II. Stucco Ceiling in a Tomb, Via L.vtina, Rome, Fir.st Century „ „ 34
III. Stucco Ceiling and Wall Decoration, Palazzo d'Albrizza,
Venice, BY A. Vittorio, 1560 - - - - - „ „ 34
IV. Stucco Ceiling, Over-door, and Wall Decoration, Palazzo
d'Albrizza, by A. Vittorio, 1560 - - - - „ „ 34
V. Stucco Pillars, Courtyard of the P.\lazzo Vecciiio, Flor-
ence, 1566 - - - - - - - ., .. 34
VI. External Plaster Work, Ancient House in Clare, Suffolk,
1473 - - - - - - - - .... 34
VII. Plaster Ceiling, LosELY House, NEAR Guildford, 1562 - „ „ 34
VIII. Plaster Ceiling, Cooper's House, Great Yarmouth, 1596 - „ „ 34 IX. Plaster Ceiling, Peartrees House, Great Yarmouth, Six- teenth Century - - - - - - .... 34
X. Plaster Ceiling, 4 South Quay, Great Yarmouth, Sixteenth
Century - - - - - - --.... 34
XI. Plaster Ceiling, Bramshill, Hampshire, 1603 - - - „ .. 34
XII. Plaster Ceiling, Audley End, 1610 - - - - „ „ 34
XIII. Plaster Ceiling, State Bedchamber, Boston House, 1623 - „ „ 34
XIV. Plaster Ceiling, Craigievar, Aberdeenspiire, 161 1 - - . ,. 34 XV. Plaster Ceiling, Moray House, Edinburgh, 161 8 - - ,. ., 34
XVI. Plaster Ceiling, Winton House, Midlothian, 1620 - - ,. „ 34
XVn. Stucco Ceiling, Holyrood Palace, Edinburgh, 1671 - - ,. ., 34
XVIII. External Plaster Work, Sparrow House, Ipswich, 1683 - „ „ 34
XIX. Plaster Ceiling, Church of St Martin's -in -the- Fields,
London, 1722 - - - - - - - .... 34
XX. Pl.aster Ceiling, Queen's Bedchamber, Palace of Versailles,
Louis XV. - - - - - - - .... 34
XXI. Plaster Ceiling, Salon des Medailles, Palace of Ver- sailles, Louis XV. - - - - - - .... 34
XXII. Plaster Ceiling, Study of the Queen of Italy's Villa,
Turin, Eighteenth Century - - - - - ■, ., 34
XXIII. Plaster Ceiling, Milton House, Canongate, Edinburgh,
1725 - - - - - - - - .... 34
XXIV. Plaster Ceiling and Cornice, Dining-room, Coleshill, Berk-
shire, by Inigo Jones, 1750 - - - - - .... 34
XII
PLATE
XXV.
XW'I.
XXVII.
XXVIIi. XXIX.
XXX.
XXXI. XXXII.
XXXIII. XXX I \'.
XXXV.
XXXVI.
XXXVII.
XXXVIII. XXXIX.
XL.
XLI.
XLII.
XLIII.
XLIV.
XLV,
XLVI. XLVII.
XLVI 1 1.
XLIX.
L.
LI.
LII.
List of Plates. I'L.vsTKK Ceiling, Queen's Room, Oij> Bl'CKIxgii.xm House,
London, dv R. An.\M, 1760
folloiving page 34
ri..\sTKR Ceii.inc, Kedleston, Dekbv.siiike, hv G. RlCII.\Kr)SON, 1770 .-------
Plaster Ceiling, Lord Montalts Mansion, Dublin, hv G. r1ciiakd.s0n, 1770 ......
Wall Decor.vtion, bv Pergolesi, 1768 -
Elevation oe Corinthian Entablature and Plan oe Cornice AT External Angle ------
Perspective View oe Plaster Ceiling in King Charles' Room, W'inton House, Midlothian, 1620, with Working Plan --------
Pla.ster Ceiling, Princes Street, Edinburgh, 1850 -
Pl.\ster Ceiling, Throne Room, Holvrood Palace, Edin- burgh, 1854 -------
Pl.\ster Ceiling at Bradford in the Ada.m Style, 1879
Pl.\ster Ceiling and Wall Decor.\tion, Hill Park House, FoREAR, Scotland, 1870 . - - - -
Decorative Plaster Work in Staircase over Entrance Hall, Park Circus, Gl.vsgow, 1880 - - - -
Plan of Drawing-room Ceiling at Toddington, Gloucester- shire, 1819 -------
Perspective View of Drawing-room at Toddington, Glou- cestershire, 1819 ------
Groined Ceiling, Trinitv College, Perthshire, 1845
Setting out and Plastering Cupola Panels and Mould- ings, AND Soffits of Arches - - -
Circular Mouldings on Circular Surfaces -
Circular Mouldings on Circular Surfaces -
Italian Renalssance Panels from Venice
Moulding Busts in Gelatine - - . - -
Ceiling in the Saloon at Coombe Park, Sevenoaks, De- signed AND Modelled bv Walter Crane -
Pla.ster Work of Mihrab in Abul Hacen's Mosque, Algiers, 1296 -------
Plaster Ceiling, Persia, Eighteenth Century
Moorish Plaster Work, Entrance to the Court of the Lions in the Alhambra, Spain, Thirteenth Century -
Diapered Pl.\ster Panelling in the Alhambra, Spain, Thirteenth Century ------
Plaster Decoration in a Synagogue, now Church called Del Transito, in Toledo, 1366 - - - .
Plaster Ceiling in a Tomb at Delhi, 1528 -
Plaster Centre Flower from Berlin, by R. Schirmer
Plasterers' Tools, Plant, and Appliances
., 34 ,, 34
facing page 1 12
134 ■36
138 138
140
140
140
140
142
164
172
174 236 326
402
424 426
428
430
432 434 444
538
LIST OF ILLUSTRATIONS IN THE TEXT.
->-♦-<-
NO. I.
3-
4-
S-
6.
7-
8.
9-
10.
1 1.
12.
13- 14- 15- 1 6.
17- i8.
19-
20. 21.
22.
23- 24.
25. 26.
27. 28.
29.
30.
Stucco decorations on a vaulted ceil- Great Baths,
ing, Rome
Stucco decorations
Pompeii - - - -
Stucco ceiling, Ducal Palace, b\- A.
Vittorio - - - -
Stucco ceiling, Scala di Giove, P'lorence Stucco decoration, Palace of Fontaine-
bleau - - - -
External plaster work, Wyvenhoe Plaster ceiling, London, 1620 Plaster ceiling. Lime Street, London,
1620 - - - -
Plaster ceiling, London, 162S Plaster ceiling, Carnock Castle Elevation and profile of cornice,
Milton House . - .
Cement testing machine Wall plumbing _ . -
Skirting formation - - -
Modillion - - _ -
Corinthian cornice - - -
Mitre mould - - - -
Frieze, Palace Chambers, London Fret ornaments Plaster ceiling, Careath House Plaster ceiling, Beeslack Fibrous plaster ceiling, Liverpool Plaster ceiling, Dublin Jack template, and spike and rope
bracket - - - -
Plan of intersection board Elevation of ribs, plan of wall inter- section board, and pin-mould Half-rib pin-mould - - -
Panels for panelled ceilings, classic
style ... -
Diminishing colunms, trammel and
floating rule - . .
Diminished fluted columns -
PAGE NO. P.\GE
31. Floating fluted columns, rim method 156
5 32. Forming fluted columns, collar method 157
33. Section of cove, showing pressed
6 screed process - - - 158
34. Floated coves, levelling rule - - J 59
10 35. Section, double diminished mould-
11 ings, false screed method - - 160 36. Elevation of double diminished
13 mouldings - - - 160
17 37. Elevations and section of running
18 mould for double diminished mouldings, diminished rule method 162
19 38. Elevations, plan, and sections of ditto,
20 top rule method - - - 163
21 39. Trammels - - - - 167 40. Template and pin-mould for running
22 elliptical arch mouldings - - 169 59 41. Setting out and constructing plasterer's
93 oval - - - - 170
lOi I 42. Plans and elevations of coved ceilings 172
113 j 43. Forming niches with running moulds 179
1 14 I 44. Plumbing running moulds - - 186 116 ! 45. Pitch of pediments - - - 192
118 I 46. Raking mouldings - - - 193
119 i 47. Side and front elevation of Ionic
135 modillion, with raking modillion - 194
136 , 48. Setting out and forming a Doric
138 portico - - - . IQ5
139 49. Setting out triglyphs - - 196 50. Setting out and forming Ionic niche - 197
144 51. Plain pedestal . - - igg
145 52. Setting out and forming compound
open pediment - - - 199
146 ' 53. Front and side elevation of modillion
146 for exterior work - - - 199
54. Setting out and forming block cornice
147 and quoins . - . 200
55. Setting out quoins - - - 201 149 56. Plan and elevation of gateway, with
152 rustications . . - 202
XIV
List of lUitstmtioiis in flic Text.
NO.
57-
58. 59-
6o.
6i. 62.
63- 64. 65. 66. 67.
68. 69. 70. /'•
/ 0-
74-
75-
76. 77- 78.
79- So. 81. 82.
83- 84. 85. 86. 87. 88. 89.
90.
91. 92.
93- 94- 95-
Columns and arches, the Corinthian
order over the Ionic on a rustic
basement - - - -
15alustrade construction
I'iain and enriched baUisters, round,
square, and octa5.j()nal on plan Examples uf pierced work for balus- trades . - - - Korminj; windows Forminj^ window heads Forming dormer window Settinij out an Klizabethan sjjable Sgraffitto frieze from I'lorence Sgraffitto frieze from Rome - Sgraffitto panels, by G. T. Robin- son, I'.S.A. Sgraffitto panels, do. do. - Sgraffitto retable, do. do. - Sgraffitto frie/cs in two colours Sgraffitto frieze in two colours Sgraffitto frieze in three colours and shading tints . - - Sgraffitto border in two colours Sgraffitto border in two colours Plaster ceiling, centre ])anel fresco, modern - - - , - Anatomical figure \'enus of Milo Exterior ornamentation in Portland
cement, mf)delled in situ - Frieze, modelled in situ Modelling stool
Hust support - - - -
Wood modelling tools Wire modelling tools Adjustable calipers - Pilaster panel from Venice - Truss . . - .
Ornamental pilaster - Patent |jlaster-box - - -
Making a front wax mould and an
open front wax mould
Making jointed and surface wax
moulds - . . .
Making a front and back wa.x mould
Making a moulding piece from a
front and back mould Plaster piece moulding a modillion - Plaster piece moulding a baluster Plaster piece moulding a vase
|
PAGE |
NO. |
|
96. |
|
|
203 |
97- |
|
205 |
98. |
|
99. |
|
|
206 |
100. |
|
101. |
|
|
207 |
102. |
|
208 |
|
|
209 |
103. |
|
210 |
|
|
21 I |
104. |
|
212 ' |
105. |
|
213 |
106. |
|
214 |
107. |
|
214 |
|
|
215 |
108. |
|
217 |
109. |
|
218 |
1 10. |
|
219 |
1 1 1. |
|
220 |
|
|
221 |
|
|
1 12. |
|
|
222 |
|
|
225 |
113- |
|
226 |
|
|
114. |
|
|
231 |
•IS- |
|
232 |
116. |
|
233 |
117. |
|
233 |
118. |
|
234 |
119. |
|
235 |
120. |
|
235 |
121. |
|
237 |
122. |
|
238 |
123. |
|
238 |
124. |
|
250 |
125. |
|
126. |
|
|
254 |
127. |
|
257 |
128. |
|
259 |
|
|
129. |
|
|
260 |
|
|
269 |
130. |
|
272 |
131 |
|
275 |
132 |
Reducing or enlarging irregular
figures . - . -
Setting out a truss and a cornice Making the model of a truss Keystone - - - -
Hinged moulds
Corinthian cajjital from Palladio Setting out Corinthian column and
pilaster capitals Section of mould for Corinthian
column capital Natural acanthus leaf Composite capital - - -
Plan and elevation of the Composite
capital - - - -
Plans, elevations, and sections of
Ionic capitals and entablature Setting out the Ionic volute Centre flower. Palace Club, London Half-section of centre flower, Palace
Club, London Plan of run body ami rim moulding
of centre flower, Palace Club,
London - - - -
Permanent joint of the body of
centre flower . . -
Centre and drop, with ornament,
roughed out in the cla_\- Prize centre flower, plan and section Soffit enrichment - - -
Internal mitre of soffit enrichment - Cast enrichment mitres To make a running mould - Section of cornice - - -
Elevation of prize cornice Twin-slippered mould Radius mould _ . .
Arch radius mould - - -
Hanging running moulds Running mould for splayed angles - Moulding a truss with gelatine Compound moulding piece for gela- tine - - - . Section and elevation of a fibrous
plaster balcony front Running concavo-convex mouldings,
do. - - - .
Section of moulding piece, do. Section of jelly mould, do. - Section of cast, do. - - -
289 291 292 294 295 296
297
298 298 299
299
300 300 303
304
305 306
306
307 308 308
309 310 312 312 313 313 314 314 315 326
333
335 336 338 338
List of Illustrations in tJie Text.
133. Fibrous plaster panel for proscenium
1 34. Section of moulding piece, do.
135. Panel mould for a fibrous plaster cast
136. Casting a fibrous plaster centre
flower - - - -
137. Casting fibrous plaster plain cornices
138. Casting fibrous plaster enriched
cornices, by the bedded enrichment system - - - -
139. Casting fibrous plaster enriched
cornices, by the cast system
140. Bench slab mould - - -
141. Finished face slab mould
142. Fibrous plaster panel with diagonal
laths - - - -
143. Setting out a reverse running mould
for a cornice . _ -
144. Reverse running mould for a cornice
casting mould
145. Reverse casting mould
146. Reverse moulds for panel mouldings
147. Reverse moulds for rib mouldings -
148. Reverse moulds for plain caps
149. Reverse casting moulds for dimin-
ished fluted columns and pilasters
150. Reverse running mould for reverse
casting mould for plain columns -
151. Reverse casting mould for plain
columns - - - -
152. Reverse moulds for over-doors
153. Panel for over-door
154. Candelabra in carton-pierre -
155. Plaster ceiling, with figure panels in
gesso - - - -
156. Ornamental plaster work on the
arcades in the Mosque of Ibn- Tulun, ninth century
157. Plaster frieze in Mosque of Sultan
Hasan, fourteenth century
158. Plaster frieze in the Mosque of En
Nasireeyeh
159. Ceiling, Kalanoun Mosque, in Cairo,
fourteenth century
160. Cornice, Kalanoun Mosque, in Cairo
161. Arabesque from the Great Mosque,
Damascus
162. Arabian panel - - -
163. Plaster and glass window from Cairo
164. Plaster frieze from Turkey -
165. Persian ceiling from Teheran
PAGE
341 342 348
351
354
357
362 369
375
377
381
382 384
384 385 385
386 38S
389 390 391 395
403 193
421 422 422
423 423
424 425 425 42s 426
166. Persian centre-piece
167. Persian plaster panel
168. Persian plaster frieze
169. Persian plaster chimney-piece and
wall decoration - - -
170. Persian plaster frieze
171. Setting out plaster prisms for penden-
tive ceilings (Moorish)
172. Indian centre-piece - - -
173. Indian centre-piece -
174. Coved ceilings of circular rooms
175. Enriched soffits of arches from Rome
176. Stucco frieze from the Ducal Palace,
Venice - - - -
177. Cartouche from the Bibliotheque
Nationale, Paris -
178. Cartouche, Lyons - - -
179. Plaster ceiling (German)
180. Plaster cornices (German) -
181. Plaster wall panel (German^
182. Plaster ceiling, Vienna
183. Plaster angle piece, Vienna -
184. Portion of an external column, Vienna
185. Pilaster panel, Brussels
186. Pilaster panel, Brussels
187. Keystones and antefix
188. Sections of concrete kerb, channel,
and paving
189. Examples of grooved surfaces
190. Half plan of coach yard
191. Plan of stable floor - Sections of the various parts of stable
floor - - - -
Sections of nosing moulds with riser boards - - - -
194. Jointed nosing mould with riser board
195. Framing for concrete stairs con-
structed in situ - - -
196. Sections of framing of soffit of stairs
197. Sections of steps - - -
198. Treads and risers - - -
199. Closed outer strings
200. Wedge casting mould
201. Moulds for casting blocks and string
mouldings - - -
Moulds for casting sills and copings Moulds for casting concrete mould-
192
202. 203.
mgs tn sttn
304.
Setting out ovals, arches, octagons, and templates - - -
XV
PAGE 427
427 428
429 430
430
434 434 437 438
439
439 440 442 443 444 445 446
447 448 44S 452
473 475 477 478
478
488 488
489 492 496 496 496 505
506 506
508
518
XVI
List of Illnstratious in the Text.
205. Setting' out arches - - - 5 '9
206. Setting out Gothic arches, panels,
and angles - - - 520
207. Setting out angle brackets for coves 522
208. Setting out angle brackets for cor-
nices . . - . 522
209. Mouldings, plain and enriched - 523
210. Setting out Roman mouldings - 525
211. Setting out Grecian mouldings - 526
212. Setting out a bead and scotia - 526
213. Columns and entablatures - - 527
214. Columns and entablatures - - 527
215. Acanthus mollis, The - - 528
216. Grecian capital . - - 535
217. Tuscan column and entablature - 530
218. Setting out an Ionic pedestal for a
column - . - - 530
219. Corinthian capital - - - 531
NO.
220.
22 1 . 222. 223.
Columns and entablatures in the
Corinthian and Composite orders Doric impost and archivolt mouldings Ionic impost and archivolt mouldings Tuscan impost and archi\olt mould-
224. Corinthian impost and archivolt
mouldings
225. Composite impost and archivolt
mouldings
226. Biilusters of the five orders and
ramjjed balustrade
227. Setting out balusters and pedestals
for balustrades
228. Mitring and stopping tools -
229. Scratch tools . . .
230. Plaster small tools - - -
231. Plasterers' plant and labourers' tools
532 533 533
533
533
533
534
535 543 544
545 547
PLASTERING-PLAIN AND DECORATIVE.
INTRODUCTORY CHAPTER. ^ GLIMPSE OF ITS HISTORY.
By G. T. ROBINSON, F..S.A.
Plastering— Prehistoric— In the Dawn of History— In Early Egypt— Amongst the Greeks and THEIR Colonies— Roman Work from the Commencement to the Decline and Fall of the Empire— Its Oriental Development— In the Middle Ages— In the Renaissance— Its Culmi- nation, in the Sixteenth Century— Its Decorative Growth in France and England— Under Francis I. AND Henry VIII.— Under the Stuart Dynasty- Its Decline under the Hanoveri.\n Influence— Its low Condition at the end of last Century— Its hoped for Revival.
Pla.STERIXG is one of the earliest instances of man's power of inductive reasoning, for when men built they plastered : at first, like the birds and the beavers, with mud, but they soon found out a more lasting and more comfortable method, and the earliest efforts of civilisation were directed to plastering. The inquiry into it takes us back to the dawn of social life, until its origin becomes mythic and prehistoric. Into that dim, obscure period we cannot penetrate far enough to see clearly, but the most distant glimpses we can obtain into it show us that man had very early attained almost to perfection in compounding material for plastering. In fact, so far as we yet know, some of the earliest plastering which has remained to us excels, in its scientific composition, that which we use at the present day, telling of ages of experimental attempts. The pyramids of Egypt contain plaster work executed at least four thousand years ago (some antiquaries, indeed, say a much longer period), and this, where wilful violence has not disturbed it, still exists in per- fection ! outvying in durability the very rock it covers, where this is not protected by its shield of plaster. Dr Flinders Petrie, in his " Pyramids and Temples of Gizeh," shows us how serviceable and intelligent a co-operator with the painter, the sculptor, and the architect, was the plasterer of those early days, and that to his care and skill we owe almost all we know of the history of these distant times and their art. Indeed the plasterer's very tools do yet remain to us, showing that the technical processes then were the same we now use, for there are in Dr Petrie's collection at University College, London, hand floats which in design, shape, and purpose, are precisely those which we use to-day. Even our newest invention of canvas plaster was well known then, and by it were made the masks which yet preserve on the mummy cases the lineaments of their occupants.
The plaster used by the Egyptians for their finest work was derived from burnt gypsum, and was therefore exactly the same as our "plaster of Paris." Its base was of lime stucco, which, when used on partitions, was laid on reeds, laced toget'ner with cords, for lathing, and Mr Millar, who has examined a fragment in Dr Petrie's collection, finds it practically " tliree coat work," about J of an inch thick, haired, and finished just as we do now.
Plaster moulds and cast slabs exist, but there does not appear any evidence of piece moulding, nor does any evidence of the use of modelled work in plaster exist. That some process of iiidurat-
2 Plastering — Plain and Decorative.
iiig plaster was tluis carl)- known is evidenced by the plaster pavement at Tel-el-Amarna, wliicli is elaborately painted. The illustration of it given on Plate I* is taken from a drawing b\- Dr Fetrie. and kindly lent b>- the editor of The Builder. This floor is laid on brick ; the first coat is of rough lime stucco about i inch thick, and the finishing coat of well-haired plaster about \ inch thick, very smooth and fine, and showing evidence of trowelling, the setting out lines for the painting being formed by a struck cord before the surface was set, and tlie painting done on fresco. It is about 60 by 20, and formed the floor of the j^rincipal room of the harem of King Amenhoted I\'., about fourteen hundred j-ears before Christ, that is, between three thousand and four thousand years ago. Long before this, plastering of fine quality e.Kisted in Egypt, and so long as its civilisa- tion continued it aided the comfort of the dwellings of its people and the beauty of its temples.
Nor was it merely for its beauty and comfort that plaster work was used. Even then its sanitary value was recogni.sed, and the directions gi\en in Le\-iticus xiv. 42-48, which was pro- bablj- written about one hundred j-ears before this date, show that the knowledge of its antiseptic qualities was widelj- spread, and the practice of it regarded as religious duty.
Unfortunately there is no direct evidence that the adjacent Assyrian powers of Nineveh and Babylon used plaster work. PossibK- the fine clay brought down hy the rivers of the Euphrates and the Tigris .sufficed for all their jjurposes. Their records are in it: their illustrations on tlic sculptured walls of their palaces are in stone, their painting is glazed on their bricks, and for them there .seems to have been but little need for plaster work, nor do we find until the rise of Grecian art anj-thing relating to our subject.
Very earlj- in Greek architecture we find the u.se of ])laster, and in this case a true lime stucco of most exquisite composition, thin, fine, and white. Some has been found at M)xena;, a city of Homeric date. \\'e know that it existed in perfection in Greece about five hundred years before the Christian era. With this the temj^les were covered externall)-, and internally where they were not built of marble, and in .some cases where they were. This fine stucco was often used as a ground on which to paint their decorati\e ornament, but not unfrequently left quite plain in its larger masses. and some of it remains in very fair preservation even to this clay. The Temple of Apollo at Bassa;, built of yellow sandstone about 470 B.C., has on its columns the remains of a fine white stucco.
Pavements of thick hard plaster, stained, of \arious colours, were common in the Greek temples. One of these, that of the Tem])le of Jupiter Panhellenius at /Egina, built about 570 Ji.c, is described bj- Cockerell as existing in the early part of this century, in good condition, though the temple itself was destroyed ; and I have seen at Agrigentum, plaster existing in perfect state, though scarcely thicker than an egg-shell, on the sheltered parts of a temple built at least three hundred years before our era, whilst the unprotected stone was weather-worn and decaj-ed.
What care the ancient Greeks bestowed on their stucco may be inferred from Pliny's state- ment that in the temple at Elis about 450 B.C., Panrenus, the nephew of Phidias, used for the groundwork of his picture " stucco mixed with milk and saffron, and polished with spittle rubbed on by the ball of the thumb, and," saj-s he, " it still retains the odour of saffron." L)sippus, the first of the Greek "realists" in sculpture, was the first we hear of who took casts of the faces of living sitters about 300 B.C., so the art of plaster casting must have advanced a good deal bj- that time, as he made presents of copies to his friends. Afterwards we read of many sculptors who sent small plaster models of their works to friends. These were, however, probably carved in the plaster rather than cast.
W hether the Greeks used stucco for modelling is a somewhat doubtful point amongst antiquarians. From certain passages in classic writers I am induced to think they did. Pausanius, * Plates I. to XWIII., illustrating this and the following chapter, will be found after page 34.
Amongst the Greeks and their Colonies. 3
who describes the temple at Stymphalus, an almost deserted and ruined city when he visited it about 130 A.D., describes the ceiling of the Temple of the Stymphalides, built about 400 B.C., as being " either of stucco or carved wood," he could not decide which, but his very doubt would imply that stucco or wood were equally common. Xow this ceiling was ornamented with panels and figures of the harpies— omens of evil, half woman and half bird, with outspread wings. He also mentions a statue of Bacchus in " coloured stucco." Of course these are not definite proofs of early Greek stucco modelling, but as the city of Stymphalus had decayed and become depopulated before 200 B.C., there is certainly presumptive evidence of the ancient practice of the art. Again, figures of unburnt earth are mentioned in contradistinction to those of terra cotta, and sundry other allusions to plastic work occur, which lead me to the opinion that quite early in Greek Art this mode of using plaster began. At any rate, we know that it was early introduced into Grecia Magna — the earliest Southern Italian colony of the Greeks ; and as colonists invariably preserve the customs and traditions of their fatherland even long after they have fallen into disuse in their native home, we can have no reason- able doubt but this art was imported rather than invented by them. Thence it spread to the Etruscans of Middle Italy, a cognate people to the Southern Greeks, by whom both plain and modelled stucco was largely used. The Etruscans, as we have seen, were more closely allied to the Greek than the Latin race, but in the course of time these two races amalgamated, the former bringing skill in handicraft, the latter lust of power, and patriotic love of country and of glory, whilst the Grecian element, which blended harmoniously with the first of these, added a love of Art This union, however, took long to ripen to artistic fruitfulness. The practical Etruscan element firstly constructed the roads and the sewers, and gave health to Rome. The Latins added to their territory until it embraced half of Europe, giving wealth to Rome, and not till the luxury and comfort thus created did the artistic element of the Greek come in, giving beauty to Rome, and the day of decorative plaster work approached its noontide glory, making Rome the attraction of the world. The absorbence of Greece as a Roman province took place B.C. 145, and the loot of it began, giving an enormous impetus to Roman Art. Thousands of statues were brought to Rome, and to be deemed a connoisseur in things artistic or a patron of the arts became the fashionable ambition. But it was not until the century just preceding the Christian era that it became especially note- worthy. Of course there is hardly anything left to us of the very early plaster work of Rome. The constant search for some new thing was inimical to the old. Old structures were pulled down to make way for new, which in their turn gave way to newer, and until the age of Augustus we have but little of the early work left. Strabo, who visited Rome about this time, complains of the destruction caused by "the numerous fires, and continued pulling down of houses rendered necessary, for even pulling down and rebuilding in order to gratify the taste is but voluntary ruin"; and Augustus, who boasted that " he found Rome of brick and left it of marble," in replacing the brick with marble destroyed the plaster work. How that plaster work was wrought we shall learn more from Vitruvius, who wrote his book on architecture about 16 B.C., and dedicated it to the emperor, " in order to explain the rules and limits of Art as a standard by which to test the merits of the buildings he had erected or might erect."
Xow, Vitruvius was a man who had travelled and seen much. He was with Julius Cxsar as a military engineer in his African campaign in 46 B.C., or ten years after Caisar's invasion of Britain. Afterwards he became a designer of military engines, what we should call head of the Ordnance Department, and also a civil engineer, persuading himself that he had a pretty taste in architecture, just as though he were an R.E. of to-day. Thus he had a practical and also an artistic training, and here is what he says on matters connected with plaster work in Book VII.,
4 Plastering— Plain and Decorative.
C"h:ii>tcr II. On tempering; lime for stucco: "This requires that the lime should be of the best cjuahty, niul tempered a long time before it is wanted for use ; so that if an\- of it be not burnt enough, the lenijtli of time emploj'ed in slakin<( it may bring the whole mass to the same consistency." He then advises it to be chopped with iron hatchets, adding that "if the iron exhibits a glutinous substance adhering to it, it indicates the richness of the lime, and the thorough slaking of it." I'or cradling out, and for ceiling joists, he recommends " the wood to be of cypress, olive, heart of oak, box, and juniper," as neither liable to "rot or shrink." For lathing he specifics, " Greek reeds bruised and tied with cords made from Spanish broom," or if these are not procurable, " marsh reeds tied with cords." On these a coat of lime and sand is laid, and an additional coat of sand is laid on to it. As it sets it is then polished w ith chalk or marble. This for ceilings. For plaster on walls he says : " The first coat on the walls is to be laid on as roughly as possible, and while drying, the sand coat spread thereon. When this work has dried, a second and a third coat is laid on. The sounder the sand coat is, the more durable the work will be. The coat of marble dust then follows, and this is to be so prepared that when used it does not stick to the trowel. Whilst the stucco is drying, another thin coat is to be laid on ; this is to be well worked and rubbed, and then still another, finer than the last. Thus with three sand coats and the same number of marble dust coats the walls will be solid, and not liable to crack." " The wall that is well covered with plaster and stucco, when well polished, not onl\- shines, but reflects to the spectators the images falling on it. The plasterers of the Greeks not only make their stucco work hard by adhering to these directions, but when the plaster is mixed, cause it to be beaten with wooden staves by a great number of men, and use it after this preparation. Hence some persons cutting slabs of plaster from ancient walls use them for tables and mirrors" (Chapter III.).
You will see by these remarks the great care taken through every process, and how guarded the watchfulness over the selection of materials, and you will also note the retrospectiveness of Vitruvius' observation, how he felt that the work done before the frantic haste of his own time was the better: very much as we find nov^-. Time is an ingredient in all good work, and its substitute difficult to find.
There are other "tips" contained in Chapter III. which are worth extraction, as, for instance, his instructions as how to plaster damp walls. In such case he primarily suggests a cavity wall, with ventilation to ensure a thorough draught, and then plastering it with " potsherd mortar," or carefully covering the rough plaster with pitch, which is then to be " lime whited over," to ensure " the second coat of pounded potsherds adhering to it," when it may be finished as already described. F"urther, he refers to modelled plaster work, which, he says, " ought to be used with a regard to propriety," and gives certain hints for its appropriate use. Speaking of pavements " used in the Grecian winter rooms, which are not only economical but useful," he advises " the earth to be excavated about 2 feet, and a foundation of potsherds well rammed in," and then a "composition of pounded coals, lime, sand, and ashes is mixed up and spread thereover, i foot in thickness, perfectly smooth and level. The surface then being rubbed with stone, it has the appearance of a black surface," " and the people, though barefoot, do not suffer from cold on this sort of pavement." Now all this bespeaks not onlj^ theoretical knowledge, but practical obser\ation and experience, and was written nearly two thousand years ago, from which you can surmise how far advanced practical plastering had then become. This written evidence is almost all we have of the work of Vitruvius' own time, for even of the time of Augustus hardly anything remains to us, as the great fire of Nero utterly destroyed the greater part of the city in the j-ear A.D. 64, and almost the only authenticated piece of plaster work done before or during his reign is the Tabula Iliaca, a
Early Roman Work. 5
bas-relief of the siege of Troy, still preserved in the Capitol Ivluseum at Rome. That this was modelled by Greek artists is proved by the fact that its inscriptions are all in Greek language, and by some it is considered to be of very much greater antiquit)-.
Illustration No. i shows a good example of the character of modelled stucco which prevailed about this period. This is a small portion of a large surface of plaster which was on a vault cut through in making the excavations for the canalization of the Tiber at Rome. There were many compartments of various sizes, and the modelling is of an exquisite delicac}\ Casts of these you can see in South Kensington Museum, and some of the smaller cartouches are almost as fine as cameos. In the same valuable museum you will find a series of arched tiles of very bright red, on which small subjects have been modelled in stucco, forming a very pleasing and suggestive combina- tion. These are from an Italo-Greek tomb, and of the early part of first century. Of about the .same date is the example given on Plate II., from the vaulted ceiling of a tomb in the Via Latina
No. i.— Stucco Decorations on a Vaulted Ceiling, Rome, Kikst Century.
at Rome, the walls of which are covered with some very delicatelj- modelled arabesque ornament. Both these are evident!}' the work of Greek artists. The more Roman method is shown in Illustration No. 2, from the Great Baths of Pompeii, which must have been executed before the year 79 A.D., when the citj' was buried by the ashes thrown up in an eruption of Vesuvius, and with it perished the natural philosopher and historian, Pliny the younger, who tells us that "no builder should employ lime which had not been slacked at least three years," " and that the Greeks used to grind their lime very fine," and that they beat it with pestles of wood. The verj- eruption which destroyed Pompeii preserved it to us, for the light scoria which fell upon it covered up the most delicate work, and it is now a museum of decorative plaster work and decorative art generallj-, for there stucco treatments abound. Not only did it decorate, but it preserved the fragile and inflam- mable structures by its fireproof coating. The ordinary plaster was evidently prepared according to the prescription of Vitruvius, the sand coating, or arenatum, he describes being here formed of decomposed lava or volcanic sand, the final coat laid on being very thin, less than yV inch in the
6 Plastcriiig — Plain and Decorative.
best work. When colour was used it was chiefly fresco, done whilst the plaster was moist. Some- times the colour was even mixed with the plaster, and every variety of plastering skill was called into ser\ice, scagliola, gesso, sgraffitto, impressed and relieved work, for J'ompcii was evidently a city of plaster work, but I am afraid the "jerry" builder was born before much of Pompeii was built, and then, as now, he relied upon the plasterer to cover up his iniquities.
There was more solid construction at Herculaneum, which was destroyed by the .same volcanic eruption, but there, unfortunately, lava, hot and semi-fluid, was the overwhelming substance, and thus the more delicate fabrics perished. Of course much of the work thus destroyed was of earlier a date than that of the catastrophe, though unfortunately we have no record of its technical history ; as far, however, as classic times are concerned, plaster work became an artistic aid, reflecting
r.
No. 2. — Stucco UEcoRATiONSi Great Bat)is, I'o.mpeii, First Century.
the general tendency of the times. Luxury begot lasciviousness and obscenity, and the moral, physical, and political decay of the Roman Empire led to its d(jwnfall, while the Puritanism begotten of the persecution of the Christians led to an iconoclastic destruction of every artistic thing, sacred and profane, and so ended artistic plastering in Rome. During Constantine's reign it passed away, and on his transfer of the capital of the Empire to Constantinople, what little building was then done then resulted in that Byzantine style of stiff, formal, plastic art which, though of archaeological value, presents nothing pertinent to the present subject. Julian " the Apostate," notwithstanding that he married Helena, the daughter of Constantine the Great, reverted from Christianity, and became a pagan about 380 a.d. He had amongst his household gods a statue of Apollo under the outstretched hand of which he daily bowed his head. Now this statue was of plaster (gypsum),
Early Italian Renaissance. 7
but it was most probably sculptured in this material, rather than cast, as we find no traces of any replica, nor does any word equi\alent to piece moulding occur in the language of this time. Hence- forward very little was done throughout the Empire until a new Rome was founded, and for more than a thousand years all relics of ornamental plaster work were buried and wellnigh forgotten. Materially, as a craft, it was debased ; the old care in preparation had disappeared, and the drudgery of careless service replaced intelligent assistance to architecture and sculpture. As an art it was dead, buried under the ruins of the buildings it had adorned, so far as Rome, the whilom capital of the world, was concerned, and there we must leave it until we come to consider its resurrection.
There is, however, little doubt but that this Eastern removal of the Empire spread the art into the far East, and it is probable that the over-enriched plaster work of India, Persia, and other parts of the Indian Empires which are in question (a question we cannot yet enter fully into, owing to the very little knowledge we possess of their archaeology), is largely due to the dissipation thus effected. The Arabian and Moorish results of this were brought back to the Western world by the Moors in the early part of the thirteenth century, to whom we owe the splendid plaster work of the Alhambra described in Chapter X\T.
During the Middle Ages plastering existed only as a craft, and its highest function was to prepare a surface to be painted on. Sometimes it was used as an external protection from the weather, but rarely was it emplo}-ed for direct adornment. Sometimes small ornaments were car\ed in plaster of Paris, but it pla}-ed no important part in decorative art, excepting, perhaps, as gesso, though this belonged rather to the painter than the plasterer; nor was it until the commence- ment of the Renaissance in Italy that it showed an\- s\-mptoms of revival.
After the long night of darkness which thus overshadowed learning and the arts, the dawn of a new era, to which wc ha\-e gi\"en the name of the Renaissance, began. With the commencement of the fifteenth century old learning and old arts began to be studied, literature leading the way, as it always does, and their study was enormously facilitated by the discovery of the art of printing, and the consequent multiplication of the copies of the lore heretofore locked up in old manuscripts. We can glean somewhat of what was the state of the plaster-worker's art at that time b\- glancing at some of the old recipes which have been handed down to us in the notebooks of the artists of that dawning time. Amongst the foremost of them was Cennini-Cennino, a painter born about 1360, a pupil for twelve years of Agnoto Gaddi, of Florence (who died in 1378J ; towards the end of his long life Cennino wrote a book compiled from his notes of all recipes and directions for the conduct of all artistic proces.ses known to him, and this book he finished on 31st July 1437 — unfortunately dating it from " the debtors' prison at Florence." He also gives us directions " how to take casts from the face of man or woman," which is much the same as our modern process, and was doubtless that of L\-sippus ; but he quaintly remarks that " when }-ou take the cast of a person of high rank, such as a lord, a king, a pope, or an emperor, )-ou should stir rose water into the plaster, but for other persons it is sufficient to use cold water from fountains, ri\ers, or wells." In taking a cast from this mould, he advises the addition of a little pounded brick. In this there is as yet no reference to piece moulding, and it is very doubtful if these processes were then known. The nearest approach to such a suggestion is contained in the instructions " how to take a cast of the whole figure of a man." " In such case you must let the person stand upright in a box, joined together lengthwise, which will reach as high as the chin. Let a thin copper plate be placed against the shoulders, beginning at the ear and reaching to the bottom of the case, and bind it with a cord to the naked person, so as not to injure or press into, the flesh. Cut four copper plates like this, and join them together like the edges of the case. Then grease the naked person, put him directly
s Plastcri)ig — Plain and Decorative.
into the case, mix a large quantity of plaster with cold water, and take care to have an assistant with you ; and while you pour plaster into the case in the front of the man, let the assistant fill the back part at the same time, so that it may be filled to the throat. Let the jjlaster rest until it be quite set and dry, then open the case, separate the edges of the case from the cojjper bands with chisels, and open it as you would a nut. Withdraw the naked person very gently, wash him quickly with clean water, for his flesh will be red as a rose. With regard to the face, >-ou may do that another time " ! I do not expect a chance to cast from a living face would occur after such a process.
This ma}-, I think, be taken as a merely theoretic instruction, showing more desire than facility, but is sufficient to show that piece moulding was not known to Ccnnino, if indeed practised by any one at his time. In another recipe he gravely bids any one wanting to take a cast of himself to spread a bed of wax about 9 inches deeji on the dining-table and tlien lie down upon it, taking care not to disturb the mould when he gets up. From this mould he takes a plaster cast, and then carefully lies down on his other side and completes the mould ! ! Comment is unnecessary, and it is onl\- from their negative value that these casting recipes of Cennino are worth remark, .showing that the desire for such a process was greater than its achievement. The real utility of his recipes, in a positive direction, are those in which he treats of gesso and other painter's u.sage of the plasterer's material. Of lime stucco he .says nothing, and all his remarks relate to plaster obtained from g)-psum found at Bologna, or Volterra, whence comes that fine white translucent alabaster of which small figures, vases, and models of buildings are made to this day. A more practical recipe, and one relating to stucco, is found in the Marciana MS., which is preserved in the Library of S. Mark, at Venice, and was written about 1503.
This is headed as "tried by Master Jacopo dc Monte S. Savino, the Sculptor." "Admirable stucco for making and modelling figures and for colouring them, and it resists water. Take of finely-pounded travertine 5 lbs., and if you would have it finer and more delicate, take fine marble instead of travertine, and 2 lbs. of slaked lime, and stir and beat them well together like a fine paste, and execute what works )ou will with it, either by forming it with your hands, or in moulds, and dry it in the shade. And if you wish to colour it white, when the work is dry enough to be tolerably firm, but not quite dr\-, grind white lead with water in the same way as colours are ground, and the flour of sifted lime, and apply it w ith a brush, and it will be very white and will effectuall)- resist water. And if you wish to colour it with other colours, let the work dry perfectly and then colour it ; but these colours will not resist water like the white. If, then, }'ou wish the colours to resist water, applj- on the work the above-mentioned composition and paint with oil colours."
This brings down the literary notice of our subject to the period of Raphael and the great revival of stucco work, before considering which we must first cast a backward glance at some evidences of pre-Raphaelite use of it. We have actual evidence of its use by Donatello, who practised it, and it is on record that he used pounded brick and glue with his stucco, and from this many of his stucchi pass as terra cottas. No doubt his object was to avoid the risk and distortion b\- baking his clay model. There is a group of the " Entombment " over the sacristy door in the Church of S. Antonicj at Padua, which was formerly considered to be in terra cotta, but is now proved to be of this brick-dust stucco. There are medallions of the Four Evangelists in true stucco in the sacristy of San Lorenzo at Florence. In South Kensington Museum there is a large stucco plaque with a low relief of the Virgin and Child, and many others are known. Now Donatello died in 1466, proving that in the first half of the fifteenth century stucco was making progress. In South Kensington Museum there is a very fine relief of the Virgin and Child surrounded by angels,
Italian Renaissance. 9
exhibiting very marked Gothic features in its accessories. This has the date 1430 attributed to it. There, too, you will find many busts of very excellent modelling and great technical skill, all done with the grey stucco. Indeed, there is plent\- of evidence that with the ad\'ance of the revival of all the arts stucco was yearning to take its wonted place beside them. Bramante, the chief architect of his day, was uncle to Raphael, and inspired his nephew with an enthusiastic love for architecture and archaeological research. He, Vasari tells us, invented "a mixture of lime" with which to decorate the exterior of his houses with festoons and friezes of foliage, and one of his last works was the building, in 1513, of Raphael's own house, which was decorated with stucco made according to the recipe from the Marciana MS., Jacopo Sansovino being one of the stucco modellers there employed. Bramante died in 15 14.
Other experimenters were at work in other parts of Italy, for the endeavour to revive the lost art of modelling in stucco was becoming general, and in Bologna Alfonso Lombardi had achieved a pre-eminent success in the renewed art. \ot only did he model many portrait busts in stucco,, and amongst them that of Emperor Charles V., which he did whilst the Emperor was sitting to Titian for his portrait, but, aspiring to greater things, he executed a large group of the death of the Virgin in a very hard stucco, which was so admired by Michael Angelo, himself a stucco worker, that on seeing it he exclaimed, " If this stucco could only become marble, it would be bad for the antique statues." Lombardi modelled many other statues in Bologna which were larger than life, all executed in the gre}' lime stucco, and Cicognara styles his figure of Hercules as the finest colossal statue of the centurj-. About the same time Andrea Verrochin really founded the art of piece moulding in Venice, and brought the casting of plaster to such a pitch of perfection that reproductions of ancient and modern works were easily obtainable, and thus formative art secured an impulse the movement of which still continues.
In 1509 Raphael came to Rome, and was in 15 15 appointed by Leo X. Director and Inspector of the search for the buried remains of Ancient Rome; and for this purpose determined, in 15 18, to unearth the remains of the Golden House of Xero, then supposed to be the Baths of Titus, and which for five hundred years had been buried under their own deca}'. Here was a great discover}- and surprise. Xot onlj- were there found painted chambers, fostering the new growth of " grotesque " ornamentation, so called from its abounding in the newly unearthed grottoes, but, more cherished than all else, abundance of modelled stucco decorations, which had survived still better their long entombment, astonishing Raphael and his attendant, Giovanni da Udine, b\- their hard- ness and brilliant whiteness. This discovery was most opportune, for the decoration of the Loggia of the Vatican was just then under consideration, and Udine set himself to work especiall}- to find out the process and the manipulation. He sa}-s he made many experiments and re-invented the process ; but as Raphael, who was not a Latin scholar, had just then had a special translation of Vitruvius into Italian made for his own study, I am disposed to think this also was exhumed about the same time. Be this as it may, the newly found stucco duro became at once the rage. With the Vatican for a cradle, and Pope Leo X. and Raphael for its sponsors, its success was ensured ; but unfortunatel}- those mephitic vapours engendered in the soil which so long had hidden this brought disease with them, and there is but little doubt that Raphael's death on the 6th of April in the following year is due to the energj- with which he sought for this buried art in the miasmatic vaults which had preserved it. B}- his last testament Raphael left the completion of his decorative works to Giulio Romano and Gio. Francesco Penni, who, for the stucco portion of these, allied them- selves with Giovanni da Udine, its re-inventor, and continued the work at the Villa Madonna, then being done for Cardinal de Medici, a cousin of Leo X., and who succeeded him as Pope in 1523.
lO
Phntcriug— Plain ami Decorative.
You can form an idea of what the moclellcd stucco here was by examining a very beautiful model of it which you will see in the South Kensington Museum ; but of the vastncss of the Villa and the richness of its surroundings it would, in a short notice, be impossible to give you an impression. Unfortunately it was partiall\- ruined before it was completed, and suffered from the barbarities of the soldiers during the sack of Rome b>' the French in 1527. That drove Udine to Florence, where he was much emplo>-ed by Cosimo de Medici and Michael Angelo, but in his old age he returned to Rome, working to the last on the Loggia, on which, as a stucco worker, he began, and where he died in 1564. He is buried in the Pantheon, close by the tomb of his loved master, Raphael, and, as sa>-s his biographer Vasari, " we ma>' believe they are now met together in eternal blessedness."
Giulio Romano went in 1524 to Mantua to carry out work for Duke Frederic Gonzaga, which Raphael had, before his death, promised to undertake, and there raised up an important school of stucco workers, who we shall see influenced the whole of Western Europe. I'ierino del Vaga, painter and sculptor, who was one of Raphael's staff of stucco workers, having begun life as a " hawk boy," went to Genoa, where he founded a great school under the patronage of the Doria family, but returned to Rome when peace was restored, and worked on the Scala Regia, and man\^ of the principal rooms in the Vatican. Jacopo Sansovino, one of the first essayers of the new- found art, went to Venice, where he fostered it, making many statues and other large works,
No. 3. — Stucco Ceili.no, Ducal Palace, by A. Vittorio, 1570.
training U|> a large school there, and in it his most celebrated pupil, Alessandro Vittorio — a man to whom nothing was impossible. He was, in fact, too facile. But as a proof of his power you can .see on Plates HI. and IV. .some of his work in the Palazzo d'Albrizzi in Venice, evidences of his ingenious and daring skill. Of a less hazardous and more restrained character is his vaulted
Late Italian Renaissance.
1 1
ceiling, shown on Illustration No. 3, from the Ducal Palace at Venice, executed about 1570, but each example of his skill is wonderfullj- \aried, and in all phases of decorative art he was an exuberant master.
No. 4. — Stucco Ceiling, Scai..\ di Giove, Florence, ey A. Vasari, 1569.
The school which Udine had founded at Florence produced great results ; \"asari, the biographer of so many artists, went there to work on the Pitti Palace in 1555, and of the interior work of that school j'ou can form some idea b}- referring to Illustration Xo. 4, where \'ou will find a portion of the ceiling from the " Scala di Giove," which \'asari commenced in 1559. There are man}- other grand ceilings in this same palace, with marvellous stucco work designed either by \'asari or the architect Ammanato, and executed by the school Giovanni da Udine established. But the most interesting example of external work, as demonstrating the perfect composition of the material and its great durabilit}', is shown in the present state of the pillars of the courtx'ard of the Palazzo Vecchio there (see Plate V.). These were done in 1566 under Vasari's direction, and as the names of good workmen are as worthy of record as are those of good designers, I, in praise of their honest and perfect workmanship, give them here. The\- are — Pietro Paulo Minocci, who afterwards settled in Parma, where he did much good work, of which some still exists ; Ricciavelli da Volterra, who afterwards joined himself to Pierino del Vaga at Genoa and in Rome, anrl ultimately came to England ; Sebastiano Tadda, whose relative Francesco was a noted worker in porphyry ; and Leonardo Marignalli, of whom I ]ia\e not been able to trace anything further. Their monument is in their work, which you will find on plaster, in Florence, and which, after five hundred )-ears, hands down the record of their craft almost as sound as the day the\- did it. With what they did it demands particular attention, and by a fortunate accident we have in a notebook
12 Plastci'iiig— Plain ami Decorative.
still preserved in the Bodleian Librarj- at Oxford, kept by I'irro Ligorio, a joint architect and coadjutor with Michael Angelo for S. Peter's at Rome, and which contains the exact recipe written just about this time. "Take," says he, "3 parts of pounded Parian marble, easily got from among the ruins in Rome and from broken statues; add I part of lime which is to be perfectl)- slaked b>- letting it lie in a heap covered with pozzuolana and exposed to the sun and rain for at least a j-car. The lime is to be made from pure white marble, not from travertine, or any other stone which is full nf holes and yellowish in tint; mix a day before with sufficient water on a tile floor. The first coat to be mixed with coarsely pounded, and the finishing coat with finel)' jjounded white marble." Now let us examine scientifically the rationale of all this. Firstl)-, the lime is pure carbonate of lime ; it was naturally burnt with wood fuel, and conse- quentlx- was free from all those sulphureous and other deleteriijus compounds inseparable from coal firing. The air slaking of it prevented the too great absorption of carbonic acid which is obtained by the free use of water, and which rather retards than assists the .setting of the stucco. Then the pulverisation of the unburnt mortar introduces a fine crystalline substance into this identical chemical composition when as yet amorphous in structure. These minute crystals induce the formation of a general crystalline structure until the final and most permanent form of all mineral substance is achieved. Thus the wisdom of the ancients achieved that which is only just dawning on the modern world of science, and the as )-ct but partially understood question zvhy lime sets, is full of thought seed for .scientific inquirj' — seed for us to propagate, and so to carry still further the lore and practice of the plasterer, and to cultivate it into fruitful knowledge. You will have remarked the absence of hair in any of these old formula; ; the rapidly induced crystallisa- tion seems to have rendered this unnecessary, for the introduction of any animal substance into plaster is an unscientific error w hich the.se old plasterers avoided.
After this digression, which these Florentine plasterers have brought about, let us return to Mantua, where we left Giulio Romano in 1524. He there did works in painting and .stucco which were renowned throughout Europe, and his school of stucco workers achieved such a reputation that Francis I. wrote to Duke Frederic Gonzaga praying him to send him some j-oung man able both as a painter and a stucco worker to assist him in decorating his new palace at Fontainebleau. This was in 1536. After conference with Giulio Romano, the Duke .sent him Francesco Primaticcio, the .son of a wealthy Bolognese merchant whom a love of art had seduced from the ways of commerce. He gathered round him a large staff of modellers, of which he became superintendent, and together the\-, according to Va.sari, " did the first stucchi ever executed in France." If the pure white stucco is meant, this was true, but there was in France a considerable attempt to model in the ordinary plaster before this, and many of the fine Gothic-hooded chimney-pieces in the chateaux are modelled in plaster on wooden cradling. At the Gros Horologe at Rouen there exists some well-modelled plaster, and there is evidence of the existence of a school of ornamental plaster workers in the valley of the Seine some years before Primaticcio's advent. At Fontainebleau, however, he did most noble figure work, much of it being considerably over life size ; long graceful figures, which formed the canon for the sculptors of the French school of Gougor, Pilon, and their followers, such as you .see in Illustration No. 5. Of course if Francis I. could thus emulate the arts of Italy in their then most fashionable phase, his great rival, our Henry VIII., could not be outdone by him. Already Cardinal Wolsey was busy fostering the Renaissance in England, and Henry sent, through his ambassadors, for those who could outvie the Italians in the service of the French king. By these means he collected many artists of renown. Amongst these were Luca and Bartholomew Penni, brothers of that Giovanni Francesco Penni whom Raphael left fellow-executor with Giulio Romano
Decorative Gyoioth in France and England.
13
for the execution of his incompleted designs. Luca, who preferred painting to plastering, did not stay long here, but deserted the king and went to join Primaticcio in France, for plasterers who could model in stucco were the subject of much diplomatic correspondence in those days. Bartholomew was here at any rate until 1539, as records of payment to him are recorded in that year. Gerome of Trevisa, who, Vasari tells us, " made many ingenious devices and one honourable house for the king's use," came, and was so much admired by King Henry VIII. that he gave him
He was killed at the siege of Boulogne in 1 544. Nicholas of
a stipend of 400 crowns a year Modena left Primaticcio, from whom he was receiving 20 livres a month, and came to help us. There was also Toto del Nunziato, whom the old account books call Anthony Toto, and who was a wax modeller at Florence, whence " sundry merchants carried him off to England, where he made all manner of works for the king, and particularly the principal palace." Now this principal palace was that of Nonsuch, which was so-called because it had no equal ; it was built at Cheam, between Sutton and Epsom, but un- fortunately not a vestige of it now exists. It was a very large and sumptuous pile, con- taining two quadrangles, and built in the half- timbered st)-le, then prevalent in Eng- land ; it was never quite finished before the king's death, but existed for more than a century, sufficiently long for record, of what these plasterers did there, to have been taken by those who admired its wonders.
The Duke of Saxe-Weimar, who saw it in 1613, tells us that "the labours of Hercules were set forth on the king's side, the queen's side exhibiting all kinds of heathen stories with naked female figures ;" and John Evelyn, who saw it in 1665, says : " I took an exact view of the plaster statues and has relievos inserted between the puncheons of the outside walls of the court, which must have been the work of some celebrated Italian. I much admired how it had lasted .so well and entire from the time of Henry VIII., exposed as they are to the air, and pit}^ it is they are not taken out
No. 5. — Stl'cco Decoration, P.^l.ace of Font.\inebleau, by Primaticcio, 1536.
14 Plastcriug— Plain and Decorative.
and placed in some dr>- place— a ^'allerj- would much become them. The\- are mcr.zo-rclkvos the size of life." You ma>- form some idea of them bj- turning to the illustration of Primaticcio's work at Fontainebleau. Unfortunatel\- we had not the white marble here to mi.x with the lime, so we could not obtain the cr\-stalline qualit)- that preserved the old Italian stucco, but we learn from a manuscript note b)^ P. le Neve that neccssit>- was the mother of invention, and that " it was done with rj-e dough very costlj-." This would dry very slowl.\-, and give toughness to the stucco whilst being modelled. I have tried it, and found it pleasant to work with, and it dries a beautiful old ivor\- colour. Having thus brought the classic art of modelling in stucco into the English Renaissance, it will be well to pause awhile and take a brief backward glance at what English plastering was before the advent of this new fashion.
What the state of plaster working was before the Romans, under Julius Ca;sar, came, we ha\e no knowledge. We know that the ancient Britons used houses built of hurdles plastered inside and out with mud — the old " wattle and dab." in fact, much of which is still done in the \\'est of England. Of course the Romans brought their arts with them, and during their four hundred }-ears' sta_\- introduced the arts and luxuries of the capital, as the numerous ruins of their buildings show. The Anglo-Saxons plastered many of their buildings inside and out, as the illumination in their MSS., and some evidences of actual work, including perhaps the plaster work on Anglo-Saxon masonr\- at the Church of Avebury in Wilts, demonstrate. The Normans were a highlj- skilled and civilised people, but we have no written records of hoiv the}' plastered ; that the\' did so is proved, by existing pictures showing painted walls of great richness, which could onl)- be done on a finely wrought field. All this was, of course, the ordinar\- lime stucco, for the use of " plaster of Paris" or calcined gypsum was unknown in this countr)' until the time of Henr)- II., who, on a visit to Paris in 1 254, so admired the superior whiteness and fineness of the walls, that he introduced it here. But plaster or lime stucco was as yet in England onl\- considered as a structural ncccssit}-, and not as a decorative adjunct ; that its fire]3ro(jf qualities and sanitary influence were known is shown b}' the edict of King John, who, after the great fire which destroyed the timber-built London Bridge in I2I2, issued an edict that "all shops on the Thames should be plastered and white-washed within and without. All houses which till now are covered with reed or rush, let them be plastered w ithin eight da\-s. and let tho.se which shall not be plastered within that time be demolished b\- the aldermen and lawful men of the \-enue (overseers). And let all houses in which brewing or baking is done be plastered within and without, that they may be safe from fire." A contract for plastering, dated 13 17, exists, wherein Adam, the plasterer, a citizen of London, agrees with Sir John de Bretagne, Earl of Richmond, to find " jjlaster of Paris" wherewith to plaster his hall well and befittingly within and without. At Clare, in Suffolk, is a fine old house (Plate VI.), stated to be dated 1473, a date I am somewhat sceptical about, with some very fine plaster work modelled in relief, with figures and scroll work, but which is evidently of a later period. In 15 19, Hermann, in his " Vulgaria," says : " Some men will have their walls plastered, some pargetted and white limed, some rough cast, some pricked, some wrought with plaster of Paris." In fact, the plasterer's and pargettor's art and craft had now become of such importance that it was formed into a separate Guild and Company in London in 1501 b}- Henr)- VH., who granted them "the right to .search and try and make and exercise due search as well, in, upon, and of all manner of stuff, touching and concerning the art and m\-stery of pargettors, commonl)- called plaisterers, and upon all work and workmen in the same art." • It is noteworthy that here pargettors are " commonly called
* This charter, having been frequently renewed with varying powers, still exists, but the only trade function the Company now performs is the granting of ^25 annually to the successful candidates in the examinations conducted bv the City and Guilds of London for Technical Examination.
I
I
Progress in England — ElizabetJian Period. 15
plaisterers," but in earlier times plasterers were commonly called pargettors. Parging was then plastering, and I am inclined to think that when the larger surfaces of the walls admitted the use of the "rule" and the "float" the distinction began. We still parge a chimnej'-flue, in which neither rule nor float can be used but only the trowel. In the old timber-framed houses the want of truth in the carpentry compelled the plaster to be laid with the trowel, hence we say they are pargetted, not plastered, and the modelling which so frequently enriched them was done with the trowel, and still bears the name of pargetry. We have thus seen how the taste of the time was prepared for the introduction of the plasterers who worked in the Italian mode introduced by Henry VIII. These kept continually coming until the death of their royal master, and having found the way here remained for many j-ears after. Thus we have a De Rudolfi here in 1550, who was most probably a relative of Bartholomew Rudolfi, who worked in Venice and Padua, where he married the youngest daughter of Titziano Minio, also a stucco worker. She likewise prosecuted the art, and is the only female stucco worker I have met with any account of Rudolfi and his wife took ser\-ice with Sigismund II., King of Poland, leaving their only (?) son here. Leonardo Ricciarelli, one of those who worked at the Palazzo Vecchio at Florence, came here in 1 570, and Luca Romano, who had worked with Primaticcio at Fontainebleau, came here after Primaticcio's death, and I have found his name as employed in England in 1586.
The English plasterers quickly learned the operative lessons these Italians taught, though they never learned the skill of their arts of design ; nor indeed was this necessary. The exigencies of English houses were different from those of Italian palaces, so they fitted their work for its purpose — a purpose never applied in any other country — that of covering a flat ceiling in a room of moderate height with a suitable plastered decoration. That this lesson was early learned is shown by some notes we have of the career of Charles Williams, the first English plasterer of whom we have anj- record as a practiser of the new art. He had most probably been one of those who were employed at Nonsuch ; at any rate he had travelled in Italy, and wrote in 1547 to Sir John Thynne, then engaged in building his house at Longleat, in Wiltshire, offering his services in supplying internal decorations upon " the Italian fashion " ; and among the papers at Longleat are two letters from Sir William Cavendish and his wife (Bess of Hardwick), begging from Sir John the use of this " cunning playsterer," who, they hear, had made " dyvers pendants and other pretty things, and had flowered the Hall at Longleat," to do like work for them at Hardwick Hall. There is but little doubt the fragment -of the frieze still remaining on the wall of the old house is his handiwork. If so, the " Italian fashion " he wrote of is more applicable to the handicraft than the design, and it is not improbable that the great frieze representing a stag hunt which )-et adorns the Council Chamber was executed by those who had studied under his direction. Of course, during the short and troubled reigns of Edward VI. and of Queen Mar\-, when England was in the throes of the inter- necine strife of politics and religion, but little decorative work was done, nor until the long and more prosperous time of Queen Elizabeth did the English plasterer have the opportunity of showing his prowess.
He had not attempted to vie with the more artistically educated foreigners, but had evoked for himself an especial decoration of his own, based in some degree on the familiar groining which had strengthened and ornamented the stone roofs with which he was familiar. Geometric rather than freehand designs were his first essa\-s. These at first consisted of interlacing squares, having radial ribs from their intersecting points, and as he grew bolder in his work these radial ribs became arched, and from their junction depended a pendant more or less ornamented, such as you may see copied, in South Kensington Museum, from a ceiling at Sizergh Hall, Westmorland, where you will
i6 P/nsfcriiii: — P/aiii and Dccomtivc.
find it in conjunction with fine Renaissance inlaid wood work. Frequentl)-, modelled foliage re- placed these radial ribs, giving the effect of a Gothic diaper to the ornamentation of the ceiling, as in that at Hurton Kirk. These simpler ceilings relied greatlj- on colour and gilding, and Edmund Spenser, the great poet of the Elizabethan era, sings in his "Visions of Bellas- " of halls where
" Goki was the parget, and the ceiling bright Did shine all scaley with great plates of gold ;"
and the ijlasterer and the painter were united, not only in their work, but in their person, — so much so, indeed, that the elder Companj- of the Painter-stainers was compelled to appeal to the Parlia- ment in the latter \-ears of the Queen's reign to restrain the plasterers from using oil colours, and they were ultimatelx', after considerable di.scussion during two Parliaments, confined to the use of distemper painting onl)-. But it was not the encroachment of the Plasterers' Compan)' by painting alone which dejjleted the trade of the Painter-stainers. The purity of the white stucco then intro- duced, and the decline of the media;val sense of colour in favour of this white homogeneous purit\-, had its effect also, and this was enforced by the richness of the ]j!astcring introduced. The geometric arrangement was no longer confined to straight lines. Curvilinear, interlacing, and knotted forms were introduced as at Loselj- (Plate VII.). The ribs were no longer of plain moulding, but embossed with running ornaments, modelled or impressed, and as the art grew, even the geometric basis was abandoned, and a free adaptation of scroll work of \er_\- large dimension was adopted. The ceiling was not sufficient for the plasterer, even though, as at Charlton in Kent, it was 115 feet in length, but his art encroached on the walls, and a deep frieze, filled with relief ornament of figure work and emblems, extended itself between the wainscot and the main cornice, as at Crewe Hall, where some of the friezes are nearlj' 6 feet dee]3, and the Hardwick Hall example, before quoted, is 1 1 feet deep. With such as these the art of painting could not then compete.
The over-mantels of the large fireplaces were filled with subject work or armorial bearings, and henceforward the plasterer was the supreme decorator ; in fact, he usur]:)ed the province of both the painter and the sculptor, and revelled in tlie large mansitjns which sprang up all over the country during the latter j'ears of Queen Elizabeth's reign and the early ones of her successor. External walls were sometimes covered with pargetry, like the cottage at Wyvenhoe, detail of which is shown in Illustration No. 6 ; and the string courses, cornices, and other external architectural features were covered with piaster as at Hollington, Kent, and Little Charlton, near Woolwich, — in fact there is hardly a single county in England or Wales which does not )et retain the evidence of the artistic powers of the plasterer. Some places, notably the older towns, once commercial centres, but now somewhat decayed in wealth, ha\e hy that absence of growth preserved much of their wonted glor\- fjr us, such as Yarmouth, which abounds with rich plaster work of the character you will see on Plates VIII., IX., X.
The early j-ears of James I. were very fruitful ones to the plasterer, and in Bramshill House, Hampshire, built in 1603, there are several ceilings, one of which you will see on Plate XI. ; but one of the finest mansions of this time is Audley End, where almost each room exhibits a \-ery varied design of ver>- noble character. This house was built by Thomas Howard, Earl of Suffolk, between 1603 and 1616. The principal room measures 66 feet b\- 30 feet, and its ceiling gives its name to it, for it is divided into thirty-two compartments, each of which is occupied by modelled groups of fish or other aquatic subjects, hence its name of the '• Fish Room." These subjects are divided b\- broad flat ribs having ver>- boldlj- arched pendentixcs at their junction, and which are
Jacobean Period.
17
covered with the most delicately modelled ornament, partly impressed and partly hand wrought. The stud}-, a room 40 feet by 24 feet, has a singularly convoluted pattern, one quarter of which you will find on Plate XII., with most delicately wrought pendants of varied design at the principal points. This design was evidently a favourite one, for there are several replicas of it existing, as at Charlton in Wilts, and sundry other places, helping to prove that these ornamental plasterers travelled from place to place, taking their patterns with them. But the triumphant example of the plasterer's work here is found in the library, a large room 60 feet by 30 feet. This area is quartered, so that each quarternal cartoon is 30 feet b)- 1 5 feet, and the whole main form is one large oval interlaced with, and intersected by, other curxilinear lines so beautifully drawn that there is not one lame or halting one in the whole of this large area— a wonderful piece of setting out, showing not only great skill in design, but most accurate eye and hand in its e.xecution. Interspersed with these fine main lines is most delicately wrought foliage work, with here and there a winged fairj- such as might have been an attendant on Titania ; indeed, this ceiling has such wonderful refinement and poetic grace that it may best be described as a plasterer's translation of Shakespeare's "Midsummer Night's Dream." There is a beauteous variety of detail throughout the whole, no formal repetition, but a rhj-thmic balance is maintained, giving an emphasis and a cadence bej-ond ex- pression, and I know of no other ceiling of this date so pure and so restrained. A much richer, though not so graceful a one, is found on Plate XIII., from the state bedroom of Boston Manor House, showing the main ribs highly decorated, and illustrating the mode of setting out
such
by quartering. On this ^^
plate is also shown a section of one of
the pendants of the same ceiling (Fig. l), No. 6.— External ri.AsrER Work, \Vy\ emiof, Si.\teemh Centiry.
together with a frieze from Bowery Hall,
Edmonton (Fig. 2). Of the external modelled work done at this time, it may suffice to mention
the fine old house at Maidstone, which bears upon it the date of 161 1, and where large panels
of scroll work, interspersed with the royal arms and the device of the Prince of -Wales, fill in the
spaces between the beams. Bishop King's House at Oxford, 1620, the George Inn at Audle\- End,
and abundant instances exist to prove its popularity.
Scotland ha\ing now annexed the kingdom of England, annexed its plasterers. .At aii_\- rate their patterns seem to have been appropriated, for they all belong to this epoch, and there does not appear to be any evidence of a national growth in Scotland, such as exists in England.
Probably the earliest of these Scottish examples is that of Craigievar, Aberdeenshire, which
3
i8
P/asfcriug — P/aiii and Dtxorative.
dates from 1611, when the castle was purchased by William Forbes, who "having made much wealth by trading in Denmark," " he plaistercd it \ery curiously," with the result shown on Plate XI v., adapting the usual pattern, common in manj- parts of England, to the arched and groined ceiling. Similar ceilings exist at Moray House, Edinburgh, one of which is shown on Plate X\'. Both of these examples show the ribs enriched with modelled ornament, and give excellent impressions of the effect of this treatment. A little later example of a similar pattern comes from W'inton House, Midlothian, done about 1620 (Plate XVI.). The design and details of all these three are so similar that it is more than probable that the}- are all the work of the same school of plasterers, whether they be Scottish or English. At Pinkie House there are many plainer ceiling.s, partaking in form the character of those found in the houses pulled down in Lime Street, London, and shown on Illustrations 7, 8, 9, proving that there was little or no
difference between the two halves of the king- dom. Under Charles I. the old st)-le of his father at first prevailed, and so late as the Survey of the Manor of Wimbledon in 1649 we read of a room in which " abo\c the wain- scot is a border of fret or parge work wrought : the ceiling is of the same fret or parge work " ; and many of the older houses yet there remain- ing ha\-c good illustrations of this survival of the older character. Yet the ad\ance in the study of Renaissance architecture under Charles I., greatly due, no doubt, to the influence of Inigo Jones, reduced this redundance of orna- ment, and ceilings of a [jlainer character, but still retaining the ribbed formation, pre\ailed, such as that shown from Carnock Castle, Stir- lingshire (Illustration Xo. 10) ; but gradually e\en these ribs disappeared from the ceiling, which was once again relegated to the painter (fostered by the works of Rubens and other imported painters) rather than to the plasterers ; but the unsettled state of the kingdom, and the Puritanic worship of plainness which set in, and continued during the Commonwealth, were well- nigh destructive to both, nor until the Restoration of Charles II. was either enabled to revive.
Born of a French mother, passing his youth chiefly abroad, the king returned to his devastated native country without any love for its national arts. The older or the wealthier families were requisitioned, repudiated, and ruined during the past troubles by one side or the other, and not unfrequently b>- both, so there was but a mere tradition of the old art left, yet sufficient remained to resuscitate it in a new fashion. This was enhanced by Sir Christopher Wren's visit to Paris in 1665, where he particularly noticed the plaster work done by \'an Ostel and Anoldino, " plaisters who perform admirable works at the Louvre," and refers to " the marble meal as the old and still the modern way of stucco work in Italy." Fostered by its new masters, the art took a floral motive for its use, and the illustration (Plate XVII.) Mr Millar provides (for the use of which he has obtained the especial permission of the Lord Chamberlain) is an excellent specimen of the
No. 7.— I'LASTER Ceiling, Lo.ndon, 1620.
Undey the Stuart Dynasty.
19
plasterer's art of the time. This is from Holyrood Palace, where it forms the ceiling of the principal staircase, and is about 24 feet square, consequently the figures in the angles representing Fame, Glory, Force, and Power are rather more than life size. The floral wreathings are full of the most delicate and beautiful modelling, the work of Italian plasterers, whose names are inscribed upon the plaster, a fact noticed b\- Mr :\Iillar when as a youth he worked on its repair. At Astle\- Hall, near Chorley, Lancashire, there is a very fine floral ceiling, enriched with flower and foliage, surmounting an elaborate frieze and cornice of figures and festoons ; and in the Church of King Charles the Martyr, at Tunbridge Wells, there is a very good ceiling, with a large hemispherical dome in the centre, having a ver}- boldlj- modelled wreathage of foliage and flowers in alto-relievo, with cherubs' heads, palm branches, and conventional foliage in its minor accessories, and an adjacent ceiling,
No. 8.— Plaster Ceiling, I.ime Street, London, 1620.
amongst cherubs' heads and palm branches, bears two dates, 16S2 and 1690. These were done by John Weatherel and Henry Hoogood, who in those two years were paid ;^I90 for their work. Similar plaster work, evidently by the same hands, was done at Groombridge Place, in the vicinity. Of course we have not much in London of the early part of Charles' time— the Great Fire destroyed the old, and the Great Plague arrested the new; but there is a ver\- beautiful specimen in St Mildred's Church, Bread Street, the ceiling of which contains a central dome supported upon arches; the cornice, marking the springing of the dome, has a very rich band of fruit and flowers, the pen- dentives are filled with well-modelled laurel branches, and rosaces and palm branches fill the panels in the arches. Once it had a band of cherubs circling round the foot of the dome, but these have been removed.
/V(rs/('r///p — P/(ii/f and Decani the.
"n — ' — r-rr
.> I .' J I .' I t il J cl J u iJ ,1 t! J y u
One of the most remarkable monuments of the plasterer's art in external work is "Sparrow's Hdusc," at Ipswich (Plate XVIII.), which was done in 1683. The house itself is about a century older, and there is very interesting internal plaster work, together with some in an exterior court, of earlier date, which is very good, but its chief glor\- is on the main front, which was apparently redecorated in consequence of the visit of " the Mcrrie .Monarch" to Ipswich in that year. Here we have modelled groups of the four quarters of the globe, with their emblems, together with a large figure of Atlas bearing the globe itself. There are festoons of foliage, St George and the Dragon, a grand escutcheon of the ro\-al arms, processional and ])astoral scenes, making this well-preserved house veritably a national monument; and Ipswich is worthy of a plasterer's pilgrimage, as he will find much other evidence of the past history of his art and craft in this quaint old port. French fashions, however, reigned supreme during the latter portion of the Stuart dynast)-, and the influence of the style of Louis XIV. made itself prominent not onl)- on the ceilings, but on the walls, where raised plaster panels with ornamental heads and bases began to prevail. This was stronglj' emphasised by the building of IMontague House, Bloomsbury, the initiative of the British Museum, by Robert Duke of Montague, who was our ambassador to the
C(nirt of Louis XIV., and who brought over Pierre Puget from Marseilles for his architect. Puget was brought up as a wood carver in a shipbuilding yard, and decked everything with flowers, for w hich he largely used stucco. Much of liis work was delegated to and done by Monnoyer, a flower jjaintcr and modeller, and henceforth naturalistically treated wreaths and festoons of flowers became the prevailing ornament, often very delicately modelled in stucco or carved on wood b\- Grinling Gibbons and his school, thus creating the so-called "Queen Anne style," which is much more talked about than understood, and which really ran through the reigns of William III. and his successors until George II. Under their influence the ceilings became divested of other panelling than a broad margin surrounding it, filled with flowing ornament, and often with rounded or incurved angles ; the cornice became of small importance, the frieze had disappeared, and a deep cove, plain or ornamental, replaced both. A good example exists at Drum House, Midlothian, where there is rdso an example of the later and richer form of this phase. An excellent specimen of this st\'le ajjplied to a \aulted ceiling is shown on Plate XIX., in the work of Arturi and Baggutti on the ceiling of St Martin's-in-the-Fields, executed about 1722, and which, apart from the ornamental detail, is an excellent specimen of the plaster work of the period. Arturi and Baggutti were then the principal workers in modelled stucco in London, and were greatly emjjloyed by Gibbs, then the most successful pupil of Sir Christopher Wren, for whom they did .some excellent work at Twickenham and at Cambridge, and who deemed them "the best" fretworkers in England. At Cambridge they were a.ssisted by Denston, a Derbyshire plasterer, who afterwards did much work of this character throughout the Midlands. The true French character of this style will be found on the Plates XX. and XXL, illustrating the ceilings of
No. 9. — I'l.ASTER CkILING, LONDOX, 1628.
The Georgian Period.
21
iiiii
llllii!;-l'ffiiiiliiijiiii!iiia|i!i!iii!i;i!iyiw^'$^^
i;"^;'i;:<M
No. 10. — Plaster Ceiling, Carnock Castle, Stirlingshire, 1640.
the Queen's bed-chamber and the Salon de Medailles at Versailles, and a good example of the Italian translation of it in that of what is now the Queen of Italy's study at Turin (Plate XXII.). Naturally the Louis XV. style followed that of Louis XIV., a more flowing and less architectural distribution of ornament took place, and the plain field of the ceiling became a more important feature, the ornament being driven into the corners and in the centres, such as you will see in Plate XXIII., where is illustrated the ceiling of a room in Milton Hou.se in the Canongate at Edinburgh, and of which type many not long ago existed in London. A combined elevation and profile of the cornice of this ceiling are shown on Illustration Xo. 11. In such as these the trophies and medallions taken from the illustrations of such works as Fontaine's Fables, and other works of French origin, were frequenth' introduced in cast plaster, to the detriment of the plasterer's art, as the moulds were, like their subjects, imported also; nor were these the only cast portions, but the repetitive cur\-es, " mutton chop bones," as they used to be called, were cast in sizes, and used to form the principal cartouches and leading lines, until their monotony called forth Ware's satire upon them, and Isaac Ware, who began his life as a chimney sweep, became a ro>-al architect, and, as the arbiter of taste, published his " Compleate Body of Architecture" in 1725. In this he .say.s, "A ceiling straggled over with arched lines and O, C's and C's and tangled semicircles may plea.se the light eye of the French, who seldom carry their obser\'ation further than a casual glance," and further tells us that " the French have furnished us with abundance of fanciful decorations for the.se purposes, little less barbarous than the Gothic"! Such an eminent dictum brought forth some English designs to amend this barbarity. So in 1773 Matthias Darlej- brought out his book
f/nstcrim: — f/ai/i and Decorative.
of dcsi^Mis in his " Comijlctc Body of Architecture," but by this time so lost was the ori^nnal plaster- work character and function that the same design \\as deemed equall>- applicable to painting or sculpture, and is often described as one "to be worked in stucco, carving, or paint." This was followed b\- Columbani's " New Book of Ornaments commonly worked in Stucco, Carving, or I'ainting"; and Chippendale, Pether, Lock, and even Batty Langley brought out books of designs for plasterers and carvers, setting a ver\- reprehensible fashion, too much followed nowada>-s, b>- divorcing design from craft, and b\- no means improving either. The ])lasterer's art thus became thoughtless and absurd, having no specific character of its own. and the dilletanti would have none of it. Simple purity became grateful to them because it was not ridiculous.
Hence came in those coffered ceilings, such as that at Sir Mark I'leNclell's house at Coleshill, Berk.shire (Tlate XXIV.), in which there is a certain amount of nobilit}-. What ornament there is, it is true is onl,\- cast work, but the coffers are deep, and give good play of light and shade, and are rigorouslj- architectural, eloquent of the T-square and the drawing board, and redolent of precedents. These were prcmonitorj- of the death of the artistic plasterer. He borrowed, not made, his designs ; he cast his ornaments, not modelled them ; he kept a stock of moulds w hich he used more or less inappropriately, fitting his borrowed design to his ornament rather than designing his ornament to
fit an original one, and his work TaTfil^g^-m^m.. ^^^-^_^^^ ^^^^ -■ .-. -...^ .-. ^ became dull, flat, stale, but by
no means to him unprofitable. Curiously enough, the very ruins of old Rome, which two centuries before had given such ,111 impetus to the plasterer's art, led to its extinction, for about the middle of the eight- eenth century there was a de- cided feeling for the exhuma- tion of the buried antiquities of Rome, and their study ; and the publication of such works as Cameron's " Baths of the Romans," Ponce's " Bains de Titus," together with the host of works treating of Roman architecture, now had an enfeebling effect after the freedom and breadth of ornament they had created. Exceedingly pretty, they pleased the |jublic taste; simple in their elements, they were easj- to design; and full of work, thej- gratified their maker ; and with here and there a cast cameo or a painting b)' Cipriani or Angelica Kauffmann, the)' were refined and delicate, such as you will find that from the Queen's room in Old Buckingham House (Plate XXV'.) ; but verj- little work was left to the art of the plasterer. He chiefly cast the models another artist had made, for when his ornament became so monotonously repetitive there was no reason wh\- he should model it separately. If you examine the ceilings from Kedleston (Plate XXVI.), Dublin (Plate XXVII.), or Pergolesi's design for a wall decoration (Plate XXVIII.), j-ou will at once see how small amount of varietj' there is in the elements of their composition. Pergolesi was brought from Italy by Robert Adam as his decorative "ghost," and brought his " pastiglio," or paste composition, with him. And now it is no longer the plasterer who adorns the house— it is the " compo man "—again an Italian, so that the race and the place which caused the resurrection of plaster modelling caused also its death. Adam, indeed, " brought death into the world," so far as this fine old art and craft is concerned. And yet there were clever plasterers
No. II.— Elevation ani> I'rofile of Cornice, Mii.tox House.
Late Workers and Examples. 23
assisting at its obsequies. Arturi, whose work we saw in St Martin's Church, Hved till 1769. We had Xaldini and Richter working here in 1770. Thomas and Charles Clark did some admirable work both in England and in Ireland from 1760 to 1780. Collins did much work for Sir William Chambers. Joseph Rose, who probably wrought on the Queen's room shown on Plate XXV., and was afterwards employed at Carlton House and Whitehall ; and John Papworth, who died in 1799, and was almost the last of a fine old race of workers. Most of these plasterers were really artists, and their modelled medallions and individual bits of design are well worthy of study ; but the vain repetition of " ornament " by the )-ard ruined them and the art expired, and perhaps the very last stucco modelling in situ done in London was on the ceiling of Hanover Chapel, Regent Street.
It may be thought I have in this short sketch of the long history of " Plaster Work, Plain and Decorative," dwelt too much on the higher development of it, but you must recollect that the higher development brings up the lower with it, and that all rise alike, so that in getting the best of one you get the best of both. Therefore, as time and space preclude the writing of an exhaustive history, I have onl\- roughly outlined some of the prominent features of its interesting past. The principal object of this chapter is to show what great artists have aforetime been the votaries of art in plaster work, and to induce those of our own day to try and revive the higher ambitions of the craftsmen of an art and craft which has such an important history, to raise it again to its former eminence, and to be no longer content with covering the sins of the "jerry-builder" with a charitable but very plain coat of indifferent plaster.
G. T. R.
CHAPTER I.
HISTORICAL PLASTERING IN ENGLAND. SCOTLAND, AND
IRELAND.
Primitive— MEDi.tVAL— Elizabethan-— Jacobean— Seventeenth and Eighteenth Centuries— Notes on Old Materials and Manipulation— Plasterers' Wages, Hours, Victuals, and Drink defined HV various Kings and Acts.
1'KIMITI\ 1'.. — The primitive mode of plastering practised in Great Britain and Ireland, before lime plastering came into general use, was with clay, mud, or sticky and unctuous earth. The rudest forms of daubing or plastering were structures erected of wattles, and daubed over with mud to keep out the cold and wet. Domestic buildings erected in this manner were in general use in the time of Henr)' II. The Devonshire "cob," a class of building not \'et e.xtinct, is a fair sample of the ancient fashion of daubing or plastering practised in this country for many centuries. In the twelfth centurj-, N'echam in his writings refers to "smoothing the surface of the walls by the trowel." According to Roger Hovcndcn, the English monarch in 1172 erected a royal residence with uncommon elegance. The London Assize of 11 89 mentions "mud plasterers, lurchers " {i.e., cob wallers) ; that of 1 2 1 2 plasterers and whitewashers (dealbatores).
After the fire, in the year 1 212, which destroyed London Bridge, and a number of houses, the bridge and the houses being made of wood, King John issued an ordinance in which the following items appear: — "All shops on the Thames be whitewashed and plastered within and without. All, houses which till now are covered with reed or rush, which can be plastered, let them be plastered within eight da\-s, and let tho.se \vhich shall not be plastered within that term be demolished bj- the alderman and lawful men of the venue. And let all houses in which brewing or baking is done, be plastered and whitewashed within and without, that they maybe safe from fire." The same ordinance fixed the rate of wages fir whitewashers and mud plasterers at 3d. per day with keep, or 4d. without keep. The mud plasterers were those who filled the spaces between the timber frames w-ith mud, clay, and straw, which was afterwards whitewashed.
In the thirteenth and fourteenth centuries the plasterers proper and the daubers formed two distinct clas.ses of workmen. The daubers were simply the la\-ers on of a mi.xture o^ clay and mud to the timber framework. The dauber or inferior plasterer of the fourteenth century received sd. per day from Easter to St Michael, and 4d. per da)- for the remainder of the
Mediceval. 25
year if at work. The daubers' labourers who attended them, as well as the tylers, received 3id. per day for one part of the year, and 3d. for the other part.
In the thirteenth century lime was sold by the bag and cwt. as at present. It was mixed with sand, and in some cases with pounded tiles. In 1282, for repairs of Newgate, the following items appear: " In the purchase of broken tiles, 2s. 4id. In four score and four bags of lime, /s. In twelve carts of sand, 2s." The pounded tiles in the mortar found in Mediaeval buildings may have led to the belief that they were of Roman origin. The architect has another item for repairs at Newgate at the same period, thus : " In plaster of Paris, bought to plaster the windows and the chamber where the Justices sit within, 13s. 4d. In wages of a plasterer and his servant, four days, 2s. 8d."
At the end of the twelfth and the beginning of the thirteenth century, the application of impressed plastic work for the purposes of architectural decoration was frequent. Delicate ornaments in low relief were impressed by means of wooden or metal tools on the moist plaster, which was afterwards painted and gilded.
MedL€VAL. — The INIediasvalists did good plaster work. The rubble walls and vaults of their churches were plastered and decorated. At Netley Abbey the vaults of rubble are covered with plaster the remains of which are still visible. At Little Bra.xted Church, Essex, an edifice in the Transitional st)-le, a thin coating of fine plaster, ^ inch thick, is found on the walls, showing good workmanship. Examples are still found at Eynsford in Kent, and at Oxford, where gable ends are covered with moulded plaster work, stamped diapers of geometrical design being slightly sunk on them. In Lancashire and Sussex half-timbered houses were plastered between the timbers with rough-cast made of lime, hay, coarse sand, and pebbles. An interesting discovery has lately been made in the Parish Church of Avebury, in Wilts. The outside of the walls of the nave above the aisle roof and around a circular window were found to be plastered, and on removing a portion of the thirteenth-century aisle wall, the plastering was found to be carried through (but not bound into it) the connection of the walls around the quoins, which were found to be of the Saxon long and short work. This plaster had not been disturbed in adding the aisle wall in the thirteenth century.
There is an interesting agreement of the reign of Edward II. '1317; concerning the plastering of the Hall of John de Bretagne, Earl of Richmond. Thus runs the agreement of the master plasterer of the fourteenth century : " Know all men that I, Adam le plastrer, citizen of London, am held bound to Sir John de Bretagne, Earl of Richmond, to find plaster of Paris, at my own proper charges, good and sufficient, without default, proper, for the hall of the said Earl, and also that I will competently, at my own proper charges, plaster and complete the said hall, and will repair the walls of the same with the said plaster, well and befittingly within and without, as also the tewels (the louvres or flues) to the summit, in such manner as befits the repair of the hall aforesaid ; and this I will do for 24 pounds sterling, which m\- lord the said Earl has paid to me beforehand. Faithfully to perform the which work within eight weeks from the day of the Hol>' Trinity next ensuing, I do bind myself and all my goods, movable and immovable, namely my lands, houses, and tenements, within the city of London being, to .distress in part of any bailiff of our lord the King," &c.
In London in the time of Edward III. (1350) the plasterers were bound to take no more for their working day between the feasts of Easter and St Michael than 6d. per day without victuals or drink, and 5d. per day for the remainder of the \-ear. Upon feast da>-s when they did not work they received no wages.
4
26 Plastering— Plain and Decorative.
A kirihcr mention of tlie jjlasterer or dauber is found in an account of mone>s expended for the repair of a house in the parish of St Michael's, CornhiU, in the reign of Edward III. (1359), vi/. : " Kor 12 cartloads of lorn (loam), 4s. ; for 9 sacks of lime, i8d. ; for 3 cartloads of sand, I2d. ; for one workman's wages for daubing, 9 daj-s at /d. per day, 5s. 3d. ; for his man the same time at 5d. per day, 3s. 9d."
A"ain, in an account of expen.ses incurred b_\- the representatives of the Cit)' attending the Parliament in 13 Richard II. (1389), the plasterers or daubers put in an a])i)earance : "For timber and carpentry, tilers and daubers, in preparing the house for their lodgings, as well as the chambers as the hall, buttery, kitchen, and stables for horses ; and for making stoles and fourvics (stools and forms) throughout, and for carting out the rubbish, such house being quite ruinous ; as also for payment made to the goodman of the house for said lodging, £t. 9s."
An example of old plaster work, as treated for external work, is to be seen in an ancient house at Clare, in Suffolk (Plate \'I.). This fine old half-timbered house, according to the date in the front, was built in 1473. Its most remarkable feature is the quaint treatment of the plaster work, which is in high relief, some of the enrichments rising 2 inches from the ground surface. Beneath the oriel bay on the first floor are two small figures supporting a shield charged with the arms of X'erdun. Beneath a window at the side of the house is a winged animal. The scroll work on this level, also that above and around the oriel baj-, appears to be all hand work.
The following reference to external stucco work is taken from the ''Vulgaria" of Hormann, dated 1519, the text of which is in Latin: "Some men will have their walls ])lastered, some pargetted and whytlymed, some rough caste, some pricked, some wrought with plaj-stcr of Paris."
At Newark there is a fine example of exterior decorative plaster work on the front of a house in the Market Place, which was built in the fifteenth century. The most ])rominent feature is a series of niches and plaster figures.
During the reign of Henry \TI1., the pupil of Wolsey, and the rival of PVancis, many Italian stucco workers found their way into this country. Nor was there any countr\- in Western Europe more fitted to receive their work than was our.;. The half-timbered framework houses, with their large surface of plastered panels, seemed purposely prepared for raised plaster work, and what we call pargetry at once established its footing. Heraldic achievements, foliage, and figure work appeared in abundance, and our ceilings were adorned with moulded compartments, filled with devices and quaint rebuses, and hung with flowered jjcndants, all modelled b\- hand ; and above all rose Nonsuch Palace, of which unfortunate])- no relic and limited records remain. Nonsuch was begun about 1527, and although the embellishment of this sumptuous palace was the hobby of the last ten j-ears of King Henry's life, it was not finished at his death. Its completion was due to the Earl of Arundel, in Queen Mar\'s da\s, to whom English art owes so much. Built according to the custom of the country, of timber framing, it was well suited for the dis])lay of the then newest fashion in decorative art. Nonsuch Palace obtained a great reputation for luxury and magnificence, and was frequently visited and mentioned by many celebrities. Leland says of it :—
" Hanc quia non habenl siinilem laudare Britanni Srcpe Solent nuUique parem cognomine dicunt." (" Unrivalled in design, the Britons tell The wondrous praises of this nonpareil.")
Queen Elizabeth was a frequent guest there. Hetzner, a German traveller, who v:.;;'.2:l t'.ie pr.'.aco in Elizabeth's time, saj-s that it was built " with an excess of magnificence ar.d elegance, even to
Sixteenth Century. 27
ostentation. One would imagine everything that architecture can perform to have been employed on this one work. There are everywhere so many statues that seem to breathe, so many miracles of consummate art, so many casts that rival even the perfection of Roman antiquity, that it may well claim and justify its name of Nonsuch, being without an equal, or, as the poet sings :—
'This which no equal has in art or fame, Britons deservedly do Nonsuch name.' ''
The Duke of Saxe-Weimar, who visited Nonsuch in 1613, tells us that the labours of Hercules were set forth on the king's side, the queen's side e.vhibiting all kinds of heathen stories, with naked female figures. Pepys, who visited it in 1665, describes all the house on the outside filled with figures. Changing hands frequently, despoiled as a royal residence during the Parliamentary wars. Nonsuch fell into decay. Evelyn saw it when neglect and vandalism had brought it well- nigh to ruin, and yet he was filled with admiration with what remained. " I took," he says, "an exact view of the plaster statues and Ims-relievos inserted between the timbers and puncheons of the outside walls of the court. I much admired how it had lasted so well and entire from the time of Henry VHI., exposed as they are to the air, and pity it is they are not taken out and placed in some dry place — a gallery would much become them. They are inezzo-relievos the size of life. The story is of heathen gods, emblems, and compartments."
The last mention of this palace occurs in James U.'s time, when P. le Neve, in his copy of Aubrey's Surrey, says he then saw it, and that it was " done with plaster work made of rye dough very costly." It is very probable that rye meal was mixed with the plaster, as the gluten would retard the setting, and the admixture work freely, and eventually become hard. This magnificent palace of plastic art, which introduced decorative modelled stucco work into England, may be justh" termed the " plasterer's pride and pleasure."
The amount of royal patronage exalted the plasterers' craft mightilj-, and from this time downwards until the end of the last century the plasterer was one of the most fertile of our art workmen, and one of the best paid. In Edward VI. 's time (1547-53) his wages were lid. per day, painters and carpenters only earning 6d. and 7d. per day, showing the superior estimation in which the plasterer was held. In fact, during the latter part of the sixteenth century, and throughout the seventeenth centur\-, there was scarcely a house of any import in the country which had not its rooms adorned with modelled plaster work — not merely the ceilings, but frequently the wall space between the high wainscot dado and the cornice was so decorated, whilst over the mantel- piece was often some large allegory or heraldic achievement wrought in stucco ; and what is parti- cularly interesting is, that in spite of all the Italian teachers who inaugurated the art, the English plasterer never became that " Diavolo incarnato, Inglese Italianato," but retained a national art speech — somewhat rough at times, it may be, but always purely vernacular.
In 1501 a charter was granted to the plasterers' craft by Henry VII., and the arms of the Plasterers' Company were granted by Henry \'III. in 1546. The following e.xtract from the charter, if put into force in the present age, would render the existence of the jerry worker and scamped work impossible : " The right to search and try and make, and exercise due search as well in, upon, and of all manner of stuff touching and concerning the art and mystery of pargettors, commonly called plaisterers, and upon all work and workmen in the said art or mystery, so that the said work might be just, true, and lawful, without any deceit or fraud whatsoever, within the city of London or suburbs thereof" In those da>-s the different parts of a building were carried out by master craftsmen. This fact is borne out by the charter granted by Charles II., which forbade any
28 Plastering — Plain and Decorative.
person from carrj-ing on simultaneously the trades of a mason, brickla>-er, and plasterer, and also forbade any person to exercise or carry on the art of a plasterer without having been apprenticed seven years. Search daj-s, as described in the charter, were annuall)- appointed up to 1832, and fines were inflicted upon offenders for using bad materials and bad workmanship.
At Boiling Hall, Yorkshire, one of the plaster ceilings is said to be fully four hundred jears old, and is considered to be one of the most remarkable specimens of the work of the period. The ornamentation, which is in high relief is most quaint, its principal characteristics being heads of dogs, bears, and foxes, from the open mouths of which issue branches of various fruit trees, different kinds of birds and animals being inserted here and there. The cornice is of considerable depth, quaintly enriched with heads and fabulous animals. The drawing-room ceiling, which is of later construction, is interesting for its free and fine treatment. At Xettlecombe, the scat of the Trevel)-ans, built in the fifteenth century, the great hall has an elaborate ceiling. The manor- house at Quantockshead, Somersetshire, built in the sixteenth century, is decorated with rich plaster friezes and ceilings. The quaint example of external plaster work on the exterior walls of a cottage at Wyvenhoe, near Colchester, was probabl)- executed in the first part of the sixteenth century. A part of this work is illustrated in Chapter I. This is taken from " Architecture of the Renaissance in England," by J. A. Gotch, F.R.I. B. A.
Some curious entries are contained in the register of St Benet's Church, Gracechurch Street, London, one of Sir Christopher Wren's buildings re-erected after the Great Fire. Thus at the accession of Queen Mary in 1553: "Paid to a plasterer for washing owte, and defacing of such Scriptures as in yo. tyme of King Edward YI. were written aboute the Churche and walls, we be commanded to do so bj- ye Right Honor. }'e Lord bishopp of Winchester, Ld. Chanr. of England, 3s. 4d."
The Duke of Wurtemberg, the " Cosen Garmobles " and " Duke de Jamaree " of Shakespeare, who visited England in 1592, was ravished with the plaster ceilings at Theobald's, &c. Once the interior plaster work glowed with gold and colour.
Shakespeare, that mighty master of man's mind and manners, mentions the [plasterer, and various kinds of plastic materials used in the seventeenth and preceding centuries. In " Henry VI.," Stafford says to Jack Cade, "Thy father was a plasterer." In "A Midsummer Night's Dream," Bottom says, "And let him have some plaster, or some loam, or some rough-cast"; and again, " Would }-ou desire lime and hair to speak better? "
An old .system of plastering, known as pargetting, was once very general. The word " parget- ting," although now seldom used except by bricklayers for the coarse plastering inside chimney flues, formerly signified plaster work decorated by means of stamps, the soft plaster being stamped or pressed to form repeated designs. Sometimes a happy combination of stamped and hand work was used for both exterior and interior plaster work. This work is sometimes called " parget work." The Elizabethan half-timbered houses exhibited on their exteriors ornamental pargetting, displaying small figures and canopies surmounting them executed in plaster work. Many specimens of old plaster work are found to contain r\-e-straw, to give it tenacity. Another kind has been discovered mixed with fibre and reeds, which was commonly used in the sixteenth century.
Pargetting is mentioned in the "Hist. Dunelm." (1450), as follows: "Johanni Bevis, pro pargetting and blanchyng, Vs." " Blanchyng " probably means cleaning or whitewashing. Bishop King's House at Oxford is a well-preserved example of figure and pargetted work. Also at Banbury, Oxfordshire, there is an ancient example of parget plaster work. The ancient house at Clare, previously mentioned, is a combination of pargetting and hand work. Other examples are to be
Sixteenth and Seventeenth Centuries. 29
seen at Parham Hall, Lavenham, Suffolk. In the "Survey of the Manors of Wimbledon" (a.d. 1649) is an entr\- which reads : "Above which (waynscot) is a border of fret or parge work wrought, having therein set eleven pictures of very good workmanship ; the seiling (ceiling) is of the same fret or parge work."
Elizabethan. — In the Elizabethan and subsequent periods plaster work was used largely in ceiling, wall, and chimney decoration. During the reigns of Elizabeth and James I. a transitional style between Gothic and Classic was developed. This style was employed in some of the most stately houses in the United Kingdom. There arose such mansions as Hatfield, Longleat, Burley, Audley End, Crewe, Littlecoats, Wilts, Chatsworth, Haddon, Hardwick, Blickling Hall, Bramshill House, Ruston Hall, and man)- others, wherein may be found rich and rare examples of plaster work, showing great excellence in design and workmanship. The ceilings are usually divided by intricate geometrically formed panelling, ornamented with foliage, heads, animals, swags, ribbons, shields, pendants, drapery, bands, and man\- other de\ices.
Sir Paul Pindar's House, London, built in the reign of Queen Elizabeth, contains some glorious old plaster ceilings. These ceilings abound in the richest and finest devices. Wreaths of flowers, panels, shields, paterae, bands, roses, ribands, and other forms of ornamentation are charmingly mingled, and unite in producing the best and happiest effect. One of them, which is all but perfect, consists of a large device in the centre representing the sacrifice of Isaac, from which a most exquisite design radiates to the very extremities of the room. In general, however, the work consists of various figures placed within multangular com]:)artments of different sizes, that in the centre of the room usually the largest. The projecting ribs, which in their turn enclose the compartments, are themselves furnished with plentiful ornamentation, consisting of bands of oak leaves and other vegetable forms, and in several instances ha\e fine pendants at the points of intersection. The cornices consist of a rich series of highly ornamental mouldings. Every part, however, is in strict keeping, and none of the details surfeit the taste or weary the eye (Cassell's " Old London ").
Losely House, near Guildford, the seat of Sir James More Molyneux, erected 1 562, contains some good plaster ceilings. Plate VII. shows a portion of one of the bedroom ceilings. The pattern is about 5 feet square before being repeated, and the panels are enriched with the moorcock and moorhen, badges of the More family. The mouldings are about 8 inches deep, and the pendants 2 feet. This is in great contrast to our modern bare whitewashed bedroom ceilings.
A fine example of external plaster work is the "Ancient House" at Ipswich, erected in 1567 (Plate XVHI.). Although built in Elizabeth's reign, its chief glory is Jacobean. The royal arms, with CIIR. in the centre, form a conspicuous feature, while a surrounding of birds, fishes, and musical instruments, together with figures representing the continents, enriched by swags of flowers and fruit, completes the harmony of the composition. In another part Atlas supports the world. St George vanquishing the Dragon is boldly depicted on one of the gables, and Phillida and Corydon adorn another side. A finely modelled triumphal procession enriches the side of another gable. The whole is probablj- hand wrought in situ. The Old Assembly Room in the same town has likewise some fine examples of hand-wrought plaster work. Mr G. Bedingfield, of Ipswich, who has repaired portions of both the above, says that the stucco is still of an extremelj- hard nature, although it has been exposed to our variable climate for over three centuries.
Great Yarmouth is rich in fine and well-preserved examples of decorative plaster work, which were executed in the Elizabethan and Jacobean periods. There is a similarity of design in some of the ceilings, especially as regards the loops at the intersection of panels. The Star Hotel, which was
T,o Plastering — Plain ami Decora live.
built in the reign of Queen Elizabeth, contains several decorative ceilings. The most notable is the Nelson Room ceiling, which is divided by flat enriched bands into six flat arched bays, which are adorned with ribbed mouldings, foliage, and pendants. The Qua)- is the centre of most pleasing plaster work. On the south side of the Row fronting the Quay is an old hou.se, now divided into two residences fXos. 46 and 47), which was probably built in 15S0. One of the ceilings is adorned with mouldings divided into compartments, in which are various devices. One represents Noah's Ark, with the dove returning with, an olive branch. Another is the figure of Neptune bestriding a sea-horse. The beam running across the ceiling is enriched with fleur-de-lis, and numerous masks of the human face adorn the sides. The fine old " Ancient House," No. 4 South Quay, was built about 1596. A portion of the drawing-room ceiling is shown in Plate VIII. This room is 30 feet by 20 feet. A peculiar feature in this, as well as in the others, is the interwoven mouldings, w hich form knots and loops at the intersections. This ceiling is divided into fifteen separate compart- ments. In an old house at the south-west corner of South Qua)- there is a very rich and elegant pendant ceiling (Plate IX.), e.xhibiting in the centre compartment the arms of James I. It will be observed that a mistake has been made in rendering the motto at the foot of the ro)-al arms. It .should be the beginning of Psalm Ixviii. (" Exurgat Deus dissipentur inimici "). The pendants at the intersections of the ribs are singular, each having on one side an angel with extended wings. In an upper chamber there is a very rich ceiling, profusely adorned with fruit and flowers. There is another curious ceiling (Plate X.) in a house in the same Quay. It appears from the design to be coeval with No. 4 South Quay. The design is somewhat similar, especially at the looped mouldings and the manipulation of the enrichments.
J.\C0lsr..\N. — At the beginning of the seventeenth century the plasterers apparent))- had taken so much upon themselves that an Act was passed, in the first year of King James, forbidding plasterers to do any painting within the city of London or in its suburbs, and restricting them to the use of some few distemper colours only. The painters did not gain much by this, for gradually painted work declined, whilst modelled work still continued in the ascendant ; but during the troublesome times of the Commonwealth it fell into disuse. With the Restoration came in the flowing rococo ornaments of French and Italian character.
A well-known writer states that "during the end of the sixteenth centur)-, and throughout the seventeenth, there was scarcely a mansion in England and Scotland which did not exemplify the plasterers' craft outside or in, and often both."
In 1547, a Charles Williams, as already mentioned, is described as being an English stucco worker of renown. He was employed by Sir John Thynne in the decorations of the new house at Longleat. His fame as a stucco worker evidently spread, for Sir W'illiam Cavendish and " Bess of Hardwick," his wife, being at that time bu.sy at Hardwick, wrote to Sir John requesting the use of this " cunning ]jlaysterer," who they hear had made " dyvers pendants and other pretty things, and flowered the Hall at Longleat," to do like work for them at Hardwick. Probably the frieze still to be seen on the ruined wall of an upper room in the old house is his work. It was more in the curious and cunning distribution of formative panelling than in figure modelling that the Englishman distinguished him.self. Our native craftsmen seem to have developed a ceiling treatment for themselves, in no waj' founded on Italian tradition or practice. Using the arrange- ment of the fan-tracery of the Late Perpendicular Gothic as a model, they founded an entirely new treatment of ribs and pendentives, often of most intricate geometric arrangement.
Bramshill House, Hampshire, the seat of Sir John Cope, Bart., dates from 1603. The drawing- room ceiling, a portion of which is depicted on Plate XL, is a fine example of the Elizabethan
Seventeenth Century. 3'
period. An uncommon feature is the introduction of narrow ribs, which are interlaced through the larger ribs, forming a separate design, j-et harmonising well with the others.
There is some quaint old plaster work in Chester, notably on the exterior of Bishop Lloyd's House. Some of the panels represent various subjects from the Old Testament, also the arms of James I.
Audley End, Essex, built about 1610, contains some of the most exquisite examples of plaster work in England. The portion of one of the ceilings shown in Plate XII. is remarkable for its most beautiful, quaint, intricate, and ingenious design. No part of the figure is repeated, and no two curves are alike. The figure, as marked, is 20 feet by 12 feet before being repeated.
The hall ceiling (Plate XIV.) of Craigievar, Aberdeenshire (161 1), is a rare example of arched work. A finely designed ribbed pendentive depends from the centre of the vault, while two smaller ones depend from the centres of the halves of the ceiling. The panels are enriched with coats of arms, foliage, &c. The general design is somewhat similar to the ceiling in Moray Hou.se.
Moray House, Canongate, Edinburgh, built in 161S, has rare examples of plaster ceilings. The one shown in Plate XV. is an excellent example of vaulted work. It is beautifull)- panelled and enriched. The main panels terminate with bold pendants.
There are some fine examples of stucco work at Hardwick Hall, Derbyshire. They consist of fine ceiling and hand-modelled stucco work on the chimney-pieces, and in the great gallery there is a fine frieze 11 feet in depth, all modelled in situ. It represents hunting subjects full of men, animals, trees, plants, &c. When Bess of Hardwick built the new house between the j-ears 1590 and 1597, she left the old one to decay ; yet there is in one of the rooms of that old roofless house a frieze similar in design to that in the new one, which has stood exposure for many generations without showing an\' signs of decaj-, good evidence of the durability of stucco. There is some modelled stucco at Haddon Hall. Over one of the chimne}--pieces is a quaint representation of Orpheus in hand-wrought stucco.
Corsham Court, Chippenham, built in the seventeenth centurj-, contains some fine examples of stucco work done in the Elizabethan stj'le. In one room there is a curious cornice, consisting of one hundred and sixty heads in basso-relievo, and all different.
In the Cotswolds there are some examples of what, in a sense, may be classed as constructional plaster work, and termed "wattle and daub." This is a rough framework of timber, covered with interlaced wicker work plastered on the outside face. The floors are pugged with lime and chopped straw. In the same district there are some stone buildings erected in the seventeenth centur\-. They are plastered in an original way by leaving the dressed stone work exposed.
There is a curious old plaster ceiling in the staircase at Quidenham Park, Norfolk. This ceiling is remarkable for its fine foliations, and having in the centre a ship pendant, dated 1619.
Illustrations Nos. 7, 8, and 9 show portions of plaster ceilings of geometrical design in old houses in Lime Street, London, which were built about 1620, and were recentlj- dismantled for street improvements. No. 8 shows elevation of the cornice and section of the ceiling through A B. Chimney-pieces and wood cornices from the same houses are now exhibited in South Kensington Museum.
Winton House, Haddington, built in 1620, is situated near Edinburgh. It was designed and built b\- William Wallace for the Earl of Winton. Wallace was appointed master-mason to the King in 161 7, and a burgess of Edinburgh in 162 1. The portion of the drawing-room ceiling (Plate XVI.) is remarkable for its great variety of well-modelled panel ornaments, which include coats of arms, crowns, monograms, figures, cherubs, and many other devices, and foliage. A
32 Plastering — Plain and Decorative.
peculiar feature in the geometrical design is the different divisions of the four oblong panels at the sides of the square panels, being alternately divided by circular and straight ribs. The figure is repeated six times in the length of the room, the whole forming a beautifully decorated ceiling. This room is about 45 feet bj- 26 feet.
The ceiling of the State bed-chamber at Boston Manor House, near Brentford, built in 1623, portrayed in Plate XIII., is peculiarly characteristic of the Elizabethan style. There is another ceiling, larger and more elaborate than the one here given, in the .same house. The princijjal figures which adorn the panels of this ceiling are personifications of the five Senses ; the four Elements ; the three Christian graces. Faith, Hope, and Charity ; War and Peace ; Peace again, and Plenty. In one of the panels the date 1623 appears, and in a corresponding panel are the initials M. R. The extraordinary number of panelled ceilings and cornices with enriched friezes in old houses of the date of Elizabeth, James I., and Charles I. and II., are remarkable for their fine plaster work. The plaster friezes are adorned with shields, festoons, foliage, and figures of the human form ; also with simple designs of strap work, with foliage and fruit.
Seventeenth .\ni) P^iohteenth Centuries. — Holyrood Palace, Edinburgh, was erected by James IV. in 1525, but the portion forming the quadrangle was only built during the reigns of Charles I. and II. Holyrood Palace contains many fine old plaster ceilings, some of which were done b>- l-'iench plasterers brought over by James I. It was during the reign of Charles II., about 167 1, that the stairca.se ceiling (Plate XVII.) and some others in the Palace (finer than this) were done by Italian plasterers, or artists, as they then were (entitled to wear ruffled shirts, lace, and to carry swords) — gentlemen of the " Minor Arti," as the Italians name them — and who travelled as the carver masons did, from job to job. The ceilings in Holyrood done by these gentlemen plasterers were modelled i)i situ while the plaster was still soft. Probably they used size water or some such material to prevent the plaster setting too quickly. The plaster was evidently gauged with lime putty, also mixed with hair, a greater portion of j)utty and hair being used for the lower stratum, and decreasing as the work proceeded to the finished surface. The work is obviously modelled /;/ situ. It has a relief and variety of detail such as could onh' be got by hand. Tool traces and the workers' names are visible in parts, and the work is still without a sign of flaw or crack. There are two quaint old buildings to be seen at Saffron Walden, Essex. They are interesting examples of old external plaster work. There is no definite and reliable information to be obtained as to their early history. On one of the gables is the date 1676. On another gable are to be found some crude but curious figures standing in bold relief in the plaster work, one armed with a spear and the other with a club. The walls are also decorated with rough quaint plaster work. There is a striking resemblance in the architecture to the ancient house in Clare, Suffolk. Plate XIX.* depicts a portion of the plaster ceiling and walls taken from the gallery in St Martin's-in-the-Fields, Trafalgar Square, London. This beautiful church was built in 1722, and designed by James Gibbs, a celebrated architect, born at Aberdeen in 1674. The internal effect is very fine from its spaciousness, stateliness, and ornamental treatment. It is divided into nave and aisles by a range of four Corinthian columns, and two pilasters on each side. Each column supports a block entablature, and from this springs a semi-elliptical ceiling over the nave. The vault is pierced transversely above the columns by semicircular arches springing from column to column. At the back of the
* This plate, from a photograph taken for " London Churches of the Seventeenth and Eighteenth Centuries," edited by G. H. Rirch, F.S..\., is reproduced by permission of the pubHsher, Mr B. T. Batsford.
Eighteenth Century. 33
block entablatures, semicircular arches are carried over the aisles, and received on consoles on the outer walls, and, b\- the intersection of these, pendentives are formed, carrying small shallow domes over the galleries. The nave terminates eastwards in two quadrants of circles on each side, and beyond is the altar recess, which has a semi-elliptical vault parallel to the nave vault. The ceiling is richly panelled, and decorated with raised plaster work, consisting of panel mouldings, relieved with a guilloche of simple yet bold design, and panels with centre flowers, paterae, angle pieces, and other foliage surrounding clouds and cupids. The royal arms of the Stuarts, in accordance with the then prevailing fashion, adorn one of the panels at the end of the ceiling near the altar. The block entablature enrichments and the column capitals are finely modelled. This effective plaster work was executed by G. .Arturi and .A. Baggutti, who also did the plaster work at St Mary's-le-Strand and many other works in plaster for James Gibbs.
The ceiling depicted in Plate XXIII. shows a little over one quarter of a ceiling in Alilton House, Edinburgh. This ceiling is in the style of Louis XV., and was executed b\- French plasterers. In 1845 my father did some repairs to this ceiling, and judging from the tool marks on the work, and the general absence of precision of balance in depth and distance of the rights and lefts of the ornament, which is always, or nearly so, found in cast work, he was of opinion that all the ornament was worked in situ by hand. Illustration No. 11 shows the elevation with profile of the cornice. Milton House was erected about 1725 for Andrew Fletcher, a son of " Fletcher of Salton." The house has recently been demolished, and a Board School erected on the site. The example of a plaster ceiling in the classic style is depicted in Plate XXIV. This shows a portion of the plan (a little over one-half) of the dining-room ceiling at Sir Mark Pleydell's Mansion, Coleshill, Berkshire, erected about 1750, and designed by Inigo Jones. An elevation of the cornice is shown at the bottom of the Plate ; this also shows section of the cornice and ceiling panel mouldings.
The plan, with elevation and section, of the ceiling depicted on Plate XXV., is one in the Queen's room in old Buckingham House (the site of Buckingham Palace). This beautiful ceiling was designed by Robert Adam about 1760, the enrichments being modelled by Rose. Adam created a style which still bears his name. The style affords but scant scope for the modeller's talent. The enrichments are mostly a series of small repeated parts, consisting generally of wreaths, or swags of husks, beads, festoons of leaves in ribbons, relieved at intervals with Etruscan vases. Many of the designs have cartouches with figures in low relief, or with paintings by artists of note, such as Kauffmann, Cipriani, and Zucchi. The style as a whole is chaste and graceful. Robert Adam was born in 1728 at Kirkcaldy, in Fifeshire.
The brothers Adam (Robert and James) are credited with introducing the plan of building several houses together, so as to represent when completed one building of imposing appearance and dimensions. The introduction of the steel fire-grate, and the practice of plastering the exteriors of brick houses, and composition enrichments for wood, iron, and plaster work, is also attributed to them. Robert died in 1792, and was honoured with a tomb in Westminster Abbey. I have given these details partly because the brothers Adam introduced into England stucco facades and composition enrichments, and parti)' because of the recent revi\-al of their style which caused a great amount of inquiries and comment in the trade.
An excellent example of Sir Christopher Wren's decorative plaster work is to be seen in the office of the Xew Ri\er Company.
In 1750, Denstone, of Derbjshire, did some fine hand-wrought plaster work at Cambridge.
An interesting example of a plaster ceiling in the antique style is depicted in Plate XXVI.
5
34 Plastering — Plain and Decorative.
This shdu- a portion of the ceilinij in the Grecian Hall at Kcdleston, Derbj-shire, executed for Lord Scarsdalc about 1770. The hall is 60 feet 6 inches by 30 feet 6 inches. The cornice is omitted from this illustration. The ceiling is parti)- coved, as indicated b}- the open spaces at the angles, which converge to the straight portion of the ceiling. The two oblong j^anels, with the oval enrichments at the straight part of the ceiling, as shown in the illustration, art repeated twice and a half to complete the length of the ceiling. This handsome ceiling was designed bj- G. Richardson, and the Grecian trophies and the other ornaments were executed by Rose.
The dressing-room ceiling (Plate XXVII.) in Lord Montalt's mansion, Dublin, was executed about 1770. The room is 24 feet long and 20 feet wide. The bas-relief in the centre panel, repre- .scnting Hercules and Omphale, was executed by E. Robbins, and the other ornaments were modelled b_v A. Collins. This elegant and chaste ceiling was designed bj- G. Richardson.
From 1750 to 17S0 A. Wilton did some fine plaster work at Cambridge, and in man)' mansions in London and vicinit\\ Wilton was the father of Wilton the .sculptor, who originall)' was brought up to his father's business, but after spending man)- )'ears in Rome he returned to London, and was one of the founders of the Ro)-al Academy.
In 1783 Thomas and Charles Clark, two Irishmen, were employed by Sir William Chambers on the fine plaster work at Somerset House. About the same time they also did some good work in Dublin. W. Collins, who died about 1793, was also employed by Sir William Chambers at Somerset House.
John I'apworth, an eminent stuccoist of London, who died in 1799, did the decorative plaster work in the great Royal Academy Room at Somerset Hou.se, and, with his eldest son, also at the rebuilding of the chapel of Greenwich Hospital, under James Stuart, the Athenian. The whole of the work was done b\- hand /;/ situ. There is a curious anecdote concerning this building. Young Papworth, some )-ears afterwards, was showing the place to a part)' of friends, and one of the guides informed them that the plasterer who did the ceiling, when lying on his back on the .scaffolding, tumbled off and was killed. Great was the astonishment of the guide when Papworth said he was the workman. Papworth was the father of a long race of architects and writers on art.
The examples of decorative plaster work mentioned in this chapter are some which I have personally seen or which have been brought to m)- notice on account of their rarity or exceptional artistic features. My readers will be aware that a great many further fine examples are to be found within the United Kingdom.
The names of other modellers and plasterers are given in other parts of this work, not onl)- as a tribute to their worth as men who gloried in their works, but also to encourage the rising generation of plasterers to endeavour to get their naines inscribed in the plasterers' niche of P"ame.
Plati: III.
Siucco Ceiling and Wall Decoration, Palazzo d'Ai.brizzi, Venice, by A. Vittorio, 156c.
Plate IV.
Stucco Ceiiini; over Dock, axu Wall Decokaitox, I'alazzo d'Ai krizzi, Venice, bv A. \"irTORio, 1560.
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Plate VII.
Portion of Plaster Ceiling, Losely House, near Guildford, 1562.
Plate VIII.
Portion of Plaster Ceiling, Cooper's House, Great Yarmouth, 1596.
Plate IX.
Portion of Plaster Ceiling, Peartref.s Hoise, Great Yarmouth, Sixteenth Century.
Plate X.
Scale o* f «rt
I'lASTER Ceiling, 4 South Quay, Great Yarmouth, Sixteenth Century.
Plate XI.
Portion of Plaster Ceiling, Bkamshili, IIoise, Hampshire, 1603.
Plate XII.
Portion of Plaster Ceiiinu, Aidi.ey End, i6io.
Plate XIII.
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Fig. 3. Plaster Ceilint., State Bed-chamber, Boston House, 1623.
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Plate XVII.
Stucco Ceiling, Holyrood Palace, Edinburgh, 1671.
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Plate XX.
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Portion of Ceiling, Qleen's Bed-chamber, Palace ok Versailles, Locis XV.
Plate XXI.
Portion of Ceiling, Salon des Medailles, Palace of Versailles, Louis W.
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Plate XXII.
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Portion of Ceii.inc, Siudy of the Queen of Italy's Villa, Turin, Eightf.enth Century.
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Plate XXIII.
Portion of Plaster Ceilinc, Milton House, Canonoate, Edinburgh, 1725-
Plate XXIV.
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Portion of Ceii.im: and Cornice, Dinin(;-room, Coi.eshii.i., Berkshire, rv Imc.o Jones, 1750.
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Plate XXV.
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Elevation with Section of Covkd Part ok Ceiling.
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Plate XXVI.
Portion of Plaster Ceiling, Kedleston, Derbyshire, by G. Richardson, 1770-
Plate XXVII.
Plaster Ceiling, Lord Montalt's Mansion, Durlin, hy G. Richardson, 1770.
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CHAPTER II.
MATERIALS.
Plaster : The Manufacture, Tests, Chemical Properties, Uses, Compressive and Adhesive Strength, OF Plaster of Paris— Limes : Hydraulic, Lias, Chalk Limes, ^L•^xuFACTURE, Calcina- tion, Slaking, and Tests — Mortar: Hardening of Mortar, :nL\gnesia in Mortar, Coarse Stuff, Lime Putty, Setting Stuff, Effects of Salt, Sugar, and Frost on Mortar, Tests and Adhesive Strength of Mortar — Hair : Ox Hair, Fibrous Substitutes for Hair— Sand : Pit, River, and Sea Sands— Mastic : Scotch and London Mastics, ^L\STIC Mouldings, Hamelein's Mastic, Mastic Cement— Stearate of Lime.
Plaster of Paris. — Gypsum, from which phister of Paris is made, is a sulphate of Hme, and is so named from two Greek words — ge, the earth ; and epsun, to concoct, i.e., concocted in the earth. In Ital)' it is known by the name oi gesso; in Scotland it is called stucco; in America it is known as calcined plaster ; and in the English trade a.s plaster. The term "plaster" will henceforth be used in this book. The writings of Theophrastus and other Greek authors prove that the use of plaster was known to them. A stone, called by Theophrastus gypsos, chiefly obtained from Syria, was used by the ancients for converting into plaster. Gj'psum is mentioned by Pliny as having been used by the ancient artists, and Strabo states that the walls of Tyre were set in gypsum. The Greeks distinguished two kinds — the pulverulent and the compact. The latter was obtained in lumps, which were burnt in furnaces, and then reduced to plaster, which was used for buildings and making casts.
Gypsum is found in most countries — Italy, Switzerland, France, Sicil)-, the United States, and some of the South American States ; also in Newfoundland and Canada. The latter is said to be the finest deposits in the world. It is found in this countrj' in the counties of Derbyshire, Cheshire, Nottingham, Cumberland, and Westmoreland. The finest gypsum is called "alabaster," and is soft, pure in colour, and fragile. This white translucent material is a compact mass of crj-stalline grains, and is used for making small statuary, vases, and other ornaments. Gypsum is found in immense quantities in the Tertiary strata of Montmartre, near Paris. This gypsum usually contains lO per cent, of carbonate of calcium, not always in intimate union with the sulphate, but interspersed in grains. This sulphate gives the Paris plaster some of its most useful properties. Pantin, near Paris, has large beds of gypsum, one bed being horizontal and over 37 feet thick.
The term "Plaster of Paris" was mainly applied to it because gypsum is found in large quantities in the Tertiary deposits of the Paris basin. Another reason is that lime and hair mortar is seldom used in Paris for plaster work, plaster of Paris being used for most kinds of internal and e.Kternal work. Plaster is known in the colour trade as terra alba. Plaster of Paris was known in England by the same name as early as the beginning of the thirteenth centur\-. The gypsum, in blocks, was brought from France, and burnt and ground here. It continued to be burnt and ground by the users until the middle of the present century. The burning was done in small ovens, and the grinding in a mill, sometimes worked by horse-power, or more often bj- hand.
-^' Plastering — Plain and Decorative
i>
Messrs J. Ramaj^c & Son, of Mdinburgh, with whom I served a jjart of my apprenticeship, burnt and ground their own plaster. I remember well that on more than one occasion I had to do a turn at the handle of the grinding machine as a punishment for some boyish indiscretion.
Plaster is the most vigorous as it is the oldest vehicle for carrying down generation after generation the masterpieces of art with which the golden age of sculpture enriched the human race. I'or reproductive uses, plaster enables youth to contemplate antiquitj' in its noblest achievements. To-day plaster is rc\okitionising industrial art for us, and in all probability for those who are to come after us. Plaster, lowly and cheap, but docile and durable, is the connecting agent with this greatest of men's endorsement in the past. Plaster thus emplojxd in duplicating works of marble, pottery, and metal work, is to-day extending the finest industries, modern and ancient. Plaster is one of the best known fire-resisting materials for building purposes. After the conflagration at Paris, it was found that beams and columns of wood which had been plastered were entirel)- protected froin fire. In cases where limestone walls had been ruined on the outside b}' the flames passing through the window openings, the same walls internally e.scapcd almost unscathed owing to their being protected with plaster. Plaster in some climates has great lasting properties. The Egj'ptians co\ered their granite sometimes, and sandstone always, with a thin coating of stucco. The Greeks coated even their marble temples with plaster, and the plaster portions are now in better jjreservation than the unprotected masonrj-, particularl)- at Agrigentum in Sicil)-.
M.-\NUFACTURE. — The gypsum is got by blasting, and by crowbars and picks. The only preparation which it undergoes before calcining consists in chipping and cleaning the outer portions if earthy, which would give the plaster a bad colour. The finest and whitest gypsum is selected for fine plaster, the darker and coarser being used for coarse plaster. There are two processes for manufacturing plaster in this couiitr_\-, viz., " boiled " and " baked."
BOILKI) Pl.V.STEK. — By the boiled process, the gypsum, after being quarried, is broken by means of a pulveriser, and then carried up by an elevator into a hopper, from which it is conducted down again by a spout to a pair of millstones, the feed being regulated by means of a small spindle attached to the cross-bar of the stones, which in revolving are made to agitate the spout, and cause the gypsum to fall in a regular stream between the stones. After grinding, the gypsum is again elevated into hoppers, which supply a large open pan or boiler to a depth of about 3 inches. The pan has large flues underneath it, heated by a furnace at one end. The gypsum is kept in agitation on this boiler by means of a pair of rakes attached to a spindle, which revolves by machinery. .Xfter it has been on the boiler for about an hour and a half, the powder becomes agitated by means of the heat, and small volcanic-like eruptions take place, through the water of hydration being driven off. At the expiration of about three hours, the powdered gypsum becomes more dense and sand-like, lying heav)- on the scrapers or rakes. This is termed by the makers as "just caught," and an experienced plaster boilcrman knows by the waj- the powder hangs when it is ready. As soon as the latter is complete, a slide which forms one of the side plates of the boiler is drawn, and the plaster is thrown off by the circular motion of the scraper. It is then left to cool, and afterwards bagged up for commerce.
The waste of gypsum in evaporation and dust which takes place in the [process of boiling is about 25 per cent. Boiled plaster is fine in texture, works verj- free, and when set is not liable to warp. It is also generall)- more reliable than baked, from the fact that each molecule is properly treated, and the material alike throughout. If the powdered gypsum is left too long on the boiler, it is burned, and will not set for a considorable time, if at all. It is also very "chalky," and if it
Plaster Manufacture. n
is not boiled enough it is also weak, so that the greatest care and experience is necessary in the boiling of plaster.
Baked Plaster. — For the baked process, several methods of heating the gypsum are adopted. A flat kiln or oven, so constructed that the fuel is never in contact with the stone, is generall)- used. The kiln is raised to a low red heat, when the firing is discontinued, and the kiln charged with lumps of gypsum. The heat is then gradually increased. After about sixteen hours the gypsum has lost its water of hydration, and after grinding becomes plaster. The kiln is sometimes worked continuously, and is heated by flues carried round the kiln. \\'hen this method is adopted, it is necessary to observe that the temperature does not rise too high, and that the plaster is drawn as soon as the water has been evaporated. Great experience is required in carrying out this process (which is simply one of dehydration) successfully, for although, when the temperature is kept within proper limits, the plaster possesses the power of reabsorbing water with avidity, this power is diminished if the gj'psum be overheated. When subjected to a red heat, the gypsum increases in density, and if this temperature be continued it gradually assumes the character of natural anhydrite, which has totally different properties to those of plaster. It is safer not to drive off the whole oi the water rather than risk exposing the gypsum to too high a temperature, as the retention of a small portion of moisture does not prevent the plaster from reabsorbing the water that has been driven off. The time required for burning depends greatly upon the quantity and hardness of the stone in the kiln. It is considered to be sufficiently baked when the plaster is of an oily nature, and adheres to the workman's fingers.
Quick axd Slow Setting Plaster. — M. Landrin, in giving the results of his long continued studies relative to the different qualities of gypsum, states that the more or less rapid setting of plaster is due to the mode in which it is burned. Its properties are very different when prepared in lumps or in powder. The former when mi.xed in its own weight of water sets in five minutes, while the latter under similar conditions takes fifteen minutes. The reason probably is that plaster in powder is more uniformly burned than when it is in lumps, which tends to prove this fact, that when the latter is exposed longer than usual to the action of heat it sets more slowlj-. Gypsum prepared at a high temperature loses more and more of its affinity for water, retaining, however, its propert\- of absorbing its water of cr\'stallisation. Plaster heated to redness and mixed in the ordinary manner will do longer set ; but if, instead of applying a large quantity of water, the smallest possible portion is used (say one-third of its weight), it will set in ten or twelve hours, and becomes extremely hard. To prepare good plaster, it should not be burned too quick to drive off all its moisture, and for its molecules to lose a part of their affinity for the water. If the plaster is exposed to heat until it has only lost 7 or 8 per cent, of its moisture it is useless, as it sets almost immediately. If, however, the burning is again resumed, the substance soon loses its moisture, and if then exposed to the air it very rapidly retakes its water of crystallisation, and absorption continues more slowly. It then sets slowly, but attains great hardness.
Testing. — The quality of plaster may be tested by simply squeezing it with the hand. If it cohere slightly, and keeps in position after the hand has been gentlj- opened, it is good ; but if it falls to pieces immediately, it has been injured by damp. Although plaster docs not chemically combine with more than one-fourth of its weight of water, _\et it is capable of forming a much larger quantity into a solid mass, the particles of plaster being converted into a network of crystals, mechanically enclosing the remainder of the water. Sulphate of lime (plaster) is soluble in water to the extent of i part in about 450, the solubility being but little influenced by temperature.
38 Plastering — Plai)t ami Decorative.
It is on account of this solubility in water that cements which have to a large extent plaster for their basis are incapable in this raw state of bearing exposure to the weather. The setting of plaster is due to hydration, or its having but little water to take up to resume a state of consolidation. Plaster is used with hydraulic limes to stop the slaking, and convert the lime into cement. These are then called "selenitic."
In lOO parts of g)-psum there are 46 acid, lime 32, and water 22 parts. Good plaster should not begin to set too soon, and it should remain for a considerable time in a creamy state. When once set it should be very hard. I'lastcr should set slowly, as it gives more time for manipulation, but principall}' because one which sets quickly and swells, never becomes so hard as slow-setting material. The quality of plaster cannot be determined by its colour, the colour being regulated by that of the gypsum ; but all things being equal, the wliitcst and hardest generally yields the best plaster. But as the exception proves the rule, it may be mentioned that the Cumberland plasters (such as Howe's) are of a delicate pink tint, and of a very fine grain, and exceedingly strong when gauged. This pink plaster is much appreciated by many plasterers for making originals, as owing to its fineness and density it is very suitable for cleaning or chasing up models taken from the clay, and also for durable moulding pieces. One of the whitest plasters in England, which is al.so very close in texture, is that manufactured by Cafferata. For cast work the colour of ])lastcr is of small moment, because the cast work is sooner or later coloured with paint, and moreover, unfortunately daubed over with distemper, or, worse still, w ith whitewash. Coarse plasters are darker in colour than fine. Coarse plasters of a sandy nature, and which rapidly sink to the bottom when put in water, contain too much silica, or improperly burnt g)-psum, or are derived from a bastr.rd gypsum, and are generally of a weak nature.
Compressive and Adhesive Strength. — The compressive resistance of properly baked plaster is about 120 lbs. to the square inch when gauged with neat water, and 160 lbs. when gauged with lime water ; thus showing that lime water hardens and improves the affinity of plaster. The adherence of plaster to itself is greater than to stone or brick. The adhesion to iron is from 24 to 37 lbs. the square inch.
Fken'CH Plaster. — A considerable quantity of I-"rench plaster was formerly used in London ; but owing to the English plaster being now more uniform in qualitj- and cheaper in price, the use of the French material is somewhat limited. A considerable quantity of gypsum is imported to Bristol from France. The stone is manufactured at Bristol, and has all the superior qualities of French plaster. This is generally known as " Bristol plaster." Benvenuto Cellini preferred the French plaster to that of Italy, his own country. In Paris various kinds of gy[jsum mortars are in general use, raw gypsum and other materials being often intermixed. They also contain free carbonate of lime, according to the degree of heat to which the raw stone has been subjected. The Hotel de Platres, in Paris, affords a good illustration of the constructive uses to which plaster can be put, some of the blocks being about a hundred years old.
Limes. — Lime is one of the most important materials in the building trades. Limestone is the general term by which all rocks are roughly classified which have carbonate of lime for their basis. They are obtained from many geological formations, varying in quality and chemical properties. The Carboniferous consists of nearly pure carbonate of lime. In the limestone of the Lias carbonate of lime is as.sociated with silica and alumina (common clay) in proportions \arying from 10 to 20 per cent. The best kinds are obtained from Aberthaw, Rugby, Barrow, and (jther districts in England ; Arden, Fife.shire, and other places in Scotland ; and Calp and Larne in Ireland. Carbonate of lime is found in a state of chemical purity in rhombohedral crystals as
Limes. 39
Iceland spar. It is also found in six-sided prisms, known to mineralogists as arragonite. Its purest form as a rock is that of white marble. Coloured marbles contain iron, manganese, &c.
The Lias strata consist of a thin layer of hard limestone separated by another of a more argillaceous character, or shale, containing various proportions of carbonate of lime. The Lias districts extend from L}me Regis to the north-east of Yorkshire ; the limestone in the counties of Warwick, Dorset, and Leicester. In the chalk districts of Kent and Surrey there are in the upper chalk a soft kind of comparatively pure carbonate of lime, and in the grey chalk lying below it there is a carbonate of lime of a harder description, having a small proportion of argillaceous matter.
Hydraulic Limes. — Hydraulic limes are those which have the property of setting under water or in damp places, where they increase in hardness and insolubility. The blue Lias lime formation is that from which hydraulic lime is principall\- obtained in England, and it is found over a wide area — at Aberthaw, and at Rugb\-, where it is also manufactured into Portland cement. This lime, while it has excellent hydraulic properties, can hardly be classed as a cement. The stones which produce these limes contain carbonate of lime, clay, and carbonate of magnesia. The clay plays an important part in giving hydraulicitj- to the lime, consequently this power is greater in proportion to the amount of cla)- contained in the lime. The proportion of clay \-aries from lo to 30 per cent. When lime contains clay it is not so easily slaked as pure lime, and does not expand so much in doing so, and therefore does not shrink so much in setting.
Lias lime (called blue Lias from the colour of the stone from which it is produced) is very variable in quality and is generally of a feeble nature, but is sometimes of an hydraulic nature. M. Vicat divides them into three classes : feebly hydraulic, ordinary h\-draulic, and eminently hydraulic. "Those belonging to the first class contain from 5 to 12 per cent, of clay. The slaking action is accompanied by cracking and heat. They also e.xpand considerably, and greatly resemble the fat limes during this process. They are generally of a buff colour." Those of the second class contain from 15 to 20 per cent, of clay. "They slake very sluggishly in an hour or so without much cracking or heat, and expand very little. They set firmlj' in a week. The eminent!}- h}-draulic limes contain from 20 to 30 per cent, of clay, are very difficult to slake, and only do so after a long time. Very frequcnti}- thej- do not slake at all, being reduced to a powder by grinding. The\- set firmly in a few hours, and are very hard in a month."
A natural h}-draulic lime, known as " Arden lime," is found in the \\'est of Scotland. This lime is obtained from what appears to be a sedimentary limestone that has been formed b\- being deposited from water which held it in solution. It is very fine grained, and contains almost no fossils, and scarcely the trace of a shell is to be seen, except at the top and bottoms of the divisions, which are four in number, and in all from 9 to 12 feet thick. When first worked, the stone was slaked in hot kilns, but now this is effected by grinding. According to the " M'Ara" process, the "lime shells" from the kiln are ground in the same way as the clinker of Portland cement. Beginning with a stone-breaker, the lime passes from this to a pair of chilled crushing rollers, and finallj- to the millstones, after which the powder is carried by screw-conveyor and elevator to a rotary .screen, 12 feet b>- 4 feet, covered with wire-cloth, which retains and returns to the millstones any residue in excess of the required fineness. Sifting is a ver\- imix)rtant factor in the proce.s.s, as it is .scarcely possible to have the millstones so perfect that the}- will not pass a few large particles.
The residue of imperfectly ground lime will doubtless slake when mixed with water, but at long or uncertain periods, so that it is obvious that fine grinding is a necessity, and the setting properties are not full}- and safely developed unless the whole is finch- pulverised. With regard to
40
Plastcritig — Plain and Decorative.
fine grinding', the expense to the manufacturer is increased in proportion to the fineness, so much .so, that to reduce the lime down to a residue of 15 per cent., instead of 35 per cent., will quite double the cost of grinding. Against this, however, a reliable natural cement is obtained. On the other hand, if coarsely ground, the covering capacitj', and subsequent strength of the mortar or concrete, is very much less. This hydraulic lime, tested on the same lines as for Portland cement, has a tensile strength per square inch at 7 days from So lbs. to 100 lbs ; i month, 150 lbs. to 200 lbs. ; 6 months, 350 lbs. to 400 lbs. ; and 3 years, 600 to 700 lbs.
The setting and hardening are mainly due to crystallisation, caused by the action of water on the silicate of lime, as shown hereafter.
The following is an analysis of hydraulic limes : —
Table I. — Analysis of Hvdraulic Limes.
|
Lime. |
Silica. |
Alumina. |
Oxide of Iron. |
.Magnesia. |
Water, Carbonic Acid, &c. |
Authority. |
|
|
Aberthaw Blue Lias - - - - |
78.45 |
9.35 |
6.25 |
trace |
... |
5-70 |
H. Faija, 1885. |
|
Barnstonc „ .... |
59.61 |
20.61 |
6.98 |
4.01 |
2.25 |
6.54 |
J. B. Dyer, F.C.S. |
|
Warmsworth Cliff(Yorks) Magnesian |
58.4 |
0.5/^ |
... |
1.4 |
38.6 |
I.l |
F. Hudson. |
Chalk Li.ME. — Chalk lime is a term u.sed principal!}- in London for fat lime. l""at lime is produced from the purest of the limestones, which are nearly pure carbonate of lime. It is also known as " pure lime " and " rich lime." As it has little or no setting power, and is easily dissolved in water, it is unfit for any purpose where strength is required, or in situations exposed to the weather.
The general practice is for lime producers to .show their lime as rich as possible by analysis, and for users to prefer a rich lime, for the reason that it makes a more plastic and better working mortar with the usual quantity of sand. Now, it has been proved by experiments, many and varied, and extending over a long jjcriod, b}- the most eminent authorities, French, German, and English, — most prominent amongst them Smcaton, — that this preference should exactly be re\ersed, and that the poorer common limes will make the best mortar, and will, in a comparatively short time, show some slight .setting power, whereas the very rich limes never take band, except in so far as the}- return to their original condition of carbonate b\' the reabsorption of carbonic acid from the atmosphere, and by the slow evaporation of the water of mixture. If it does not evaporate, the mortar remains always soft. If it evaporates too quickly, the mortar falls to powder, a result which must be in every one's experience who has witnessed the taking down of old buildings, and the clouds of dust created by the removal of every stone.
Some of the stones from which fat lime is produced contain a proportion of .sand as an impurit)'. They therefore yield an inferior substance. This, though cheaper, is not so economical as pure lime, as it does not increase its volume so much when slaked. The pure or fat lime should only be used for plastering, as it is easily slaked, and therefore not so liable to blister as most hydraulic limes. It expands to double its bulk when slaked, and can be left and reworked again and again without injuring it.
Amongst the great variety of Scotch limes, those of the Murlet and Campsie series have a
Calcining Lime. 41
reputation which has been handed down for generations. The analysis of the lime from the mines of the Hurlet and Campsie Akim Company gives the following proportions :— Carbonate of lime, 91.40 ; carbonate of magnesia, 3.40 ; carbonate of iron, 2.07 ; bi-sulphide of iron, .41 ; alumina, .60 ; silica, i.OO ; phosphoric acid, .10 ; coaly matter, .80 ; water, .10.
Irish rich lime, as used in the West of Scotland for the finishing coat of plaster work, is slaked by immersion, as the Romans are said to have prepared their limes. This "lime putty," prepared by immersion for a longer or shorter period — seldom less than three weeks — before being used, is laid on in a very thin coat, and gives a hard skin to the surface. This hardness is largely, if not wholly, due to the fact that the lime is laid on in a thin layer on the floating coat that has already absorbed carbonic acid from the air. This thin layer becomes harder than the main body of the plaster.
The whole process of preparing lime and laying it on the walls in thin coats, with a con- siderable space of time between the coatings, is conducive to the ultimate hardness of the whole. The lime is first slaked, and then made into coarse stuff and setting stuff, all this time being exposed to the carbonic acid of the atmosphere. Again, each coat is long exposed to the same influence before being covered with the next, altogether in marked contrast to the system of using the mortar in building.
Calcination. — The process of " lime-burning " is carried out in several different ways. But whether the operation be carried out in the simplest manner, or in kilns constructed on the most scientific principles, it will still depend (both as regards the quality and quantity of lime produced; upon the kilnsman, as it is onl\- by constant observation from day to day that the man becomes capable of judging whether the proper temperature has been reached, or that a correct opinion can be formed as to the effects produced by the various disturbing causes which exert an important influence upon the working of a kiln, such as its size, shape, the qualit\' of the fuel, and the state of the atmosphere. The kilns vary in size and shape in different districts, though they are generally inverted cones or ellipsoids, into which layers of limestone and fuel are alternately thrown. When worked continuously as running kilns, the lime is periodically withdrawn from below, fresh quantities of fuel and stone being filled in at the top. When lime has not been properly calcined, or " dead burnt," it will not slake with water. This may arise from two causes — from insufficient burning, when the limestone, instead of being entirely caustified, has only been changed into a basic carbonate, consisting of two equivalents of lime and one of carbonic acid, one-half only of its carbonic acid having been expelled. This basic carbonate, on the addition of water, instead of forming a hydrate of lime, and being converted into a fine and impalpable powder, attended with the production of a large amount of heat, is changed, with little elevation of temperature, into a mixture of hydrate and carbonate. In the case of hydraulic limes which contain a considerable amount of silica, this "dead burning " maj- arise from the limestone having been subjected to a too high temperature, whereby a partial fusion of the silicate of lime formed has been produced, giving an impervious coating to the inner portions of the stone, retarding the further evolution of the carbonic acid. On this account the eminently hydraulic limes require to be carefulK- calcined at as low a temperature as practicable ; and hence it is not infrequentl\- found that Lias lime has been imperfectly calcined. Pure limes, if subjected to an e.xcessive temperature, exhibit somewhat less tendency to combine with water than is the case with lime properly calcined. Caustic lime unites with water with great energy, so much so as to evolve a very considerable amount of heat. When water is poured upon a piece of well-burnt lime heat is rapidly generated, and the lime breaks up with a hissing, crackling noise, the whole mass being converted in a short time into a soft, impalpable powder, known as " slaked lime."
6
42 Plastering — Plain ami Decorative.
Slakinc. — Chemically speaking, slaked lime is liydrate of lime — that is, lime chemically combined with a definite amount of water. In the process termed "slaking," one equivalent or combining proportion of lime unites with one equivalent of water, or in actual weight 28 lbs. of lime combines with 91 lbs. of water (being nearly in the proportion of three to one) to form 37 lbs. of solid hjdratc of lime. The water loses its liquiil condition, and it is to this solidification of water that the heat developed during the process of slaking is partly due. In England the burnt lime, before it is slaked, is generally called " lump lime," in Scotland it is called " shells."
Slaking is a most important part in the process of making coarse stuff and putt)' lime. Unless the slaking is carefully and thoroughly done, the resultant materials are liable to "blister" or " blow," owing to small particles still remaining in a caustic state. Blisters may not show until a considerable time has elapsed. There are three methods of slaking "lump lime" — the first by immersion ; the second by sprinkling with water ; and the third by allowing the lime to slake by absorbing the moisture of the atmosphere. Rich limes are capable of being slaked by immersion, and kept in a plastic state. They gain in strength b\' being kept under cover or water. I'liny states that the Romans had such great faith in this method that the ancient laws forbade the use of lime unless it had been kept for three years. All rich limes may be slaked by mixing with a sufficient quantity of water, so as to reduce the whole to a thick paste. Lump lime should first be broken into small pieces, placed in layers of about 6 inches thick, and uniforml)- sprinkled with water through a pipe having a rose on one end, or by means of a large watering-can having also a rose, and covered quickly with .sand. It should be left in this state for at least twenty-four hours before being turned over and passed through a riddle. The layer of sand retains the heat developed, and enables the process of slaking to be carried out slowly throughout the ma.ss. Any un.slaked lumps may be put into the middle of the next heap to be slaked. The quantity of water should be properly regulated, as if over-watered a useless paste is formed. If a sufficient quantity is not supplied, a dangerous powdering lime is produced. Slaking by sprinkling and covering the lime lumps is frequently done in a ver>' imperfect and partial manner, and portions of the lime continue to slake long after the mortar has been used. Special care must be exercised, and sufficient time must be allowed for the lime to slake when this method is emploj-ed.
Different qualities of lime require variable amounts of water ; but the medium quantity is about a gallon and a half to ever)' bushel of lime. No water should be added or the mass disturbed after slaking has begun. In most parts of England the lime for making coarse stuff is generally slaked by immersion, and is run into a pit, the sides of which are usually made up with boards, brick work, or .sand, the lime being put into a large tub containing water. When the lime is slaked, it is lifted out by means of a pail, and poured through a coar.se sieve. It is sometimes made in a large oblong box, having a movable or sliding grating at one end to allow the lime to run out, and also to prevent the sediment from passing through.
In preparing lime for plaster work, the general practice in the North of Enghuul is to slake it for three weeks before using. Not only so, but a particular cool lime is selected, for the reason that it is not liable to blister and deface the internal walls when finished. Now, while all this precaution is taken in regard to plastering, in making mortar for building the lime is slaked and made up at once, and it is frequently used within a day or two. But this is not all. Limes which are unsuitable for plaster work, known as hot limes, and which, when plasterers are obliged to use, must be slaked for a period of^not three weeks, but more— nearly three months before using, and are then not quite safe from blistering, are the limes mostly used for building purposes. It will
Mortars. 43
at once be seen that when mortars of these h'mes are used immediately, the unslaked particles go on slaking for a long time, drying up the moisture, and leaving only a friable dust in the joints. This should help in understanding the old Roman law which enacted that lime should be slaked for three years before using. If three years should seem to us an absurd time, yet it may be justlj- said that at least three months are required to slake completely, and to develop fully the qualities of many of the common limes in everyday use. Major-General Gillmore, an eminent American specialist, and a recent writer on the subject of Limes and Cement, mentions that in the South of Europe it is the custom to slake the lime the season before it is to be used.
Mortar. — This is a term used for various admixtures of lime or cement, with or without sand. For plaster work it is usually composed of slaked lime, mixed with sand and hair, and is termed "coarse stuff," and sometimes "lime and hair," also "lime." In Scotland the coarse stuff is generally obtained by slaking the lump lime (locally termed shells) with a combination of water sprinkling and absorption. The lime is placed in a ring of sand, in the proportion of one of lime to three of sand, and water is then thrown on in sufficient quantities to slake the greater portion. The whole is then covered up with the sand, and allowed to stand for a day ; then turned over, and allowed to stand for another day ; afterwards it is put through a riddle to free it from lumps, and allowed to stand for six weeks (sometimes more) to further slake b\- absorption. It is next " soured " — that is, mixed with hair ready for use. Sometimes when soured the stuff is made up in a large heap, and worked up again as required for use. This method makes a sound reliable mortar. In some parts lime slaked as above is mixed with an equal part of run lime. This latter method makes the coarse stuff " fatter," and works freer. All slaked limes have a greater affinity for water than the mechanically ground limes.
Grinding is another process for making mortar or " lime," and if made with any kind of limestone is beneficial. It thoroughly mi.xes the material, increases the adhesion, adds to the density, and prevents blistering. When there is a mortar-mill, either ground or lump lime can be used, and the coarse stuff maj' be made in the proportion of i part lime and 3 parts sand. The lime should be left in the mill until thoroughly reduced and incorporated, but excessive grinding is detrimental. The process should not be continued more than thirty minutes. Both material and strength is economised if lump lime is slaked before being put in the mill.
When a mortar-mill is used for grinding the lime, the sand may be partl\- or wholly dispensed with, and excellent results are obtained by using old broken bricks (clean and well burnt), stone chippings, furnace cinders (free from coal), or slag. It is most essential in all cases that the materials used should be perfectly clean. It should be borne in mind that a complete incorpora- tion of the ingredients is essential in the slaking and mixing for coarse stuff, whether done b)- hand or machine. The sand or other material used can be tested by washing a portion in a basin of clean water, then sifting through a fine sieve. If there is an undue residue of clay, fine dust, or mud in the water or sieve, the whole of the aggregate should be washed or rejected. Lias lime should be mixed dry with sand, and damped down for seven or ten days to ensure slaking. It should not be used fresh for floating or rendering. Pure or rich limes are not so well adapted for outside work, or places exposed to the action of damp, as hydraulic limes. Mortar should be well tempered before using. Pliny states that it was an ancient practice to beat the mortar for a long time with a heavy pestle just before being used, the effect of which would be not only more thoroughly to mix the materials, but to take from the outside of the sand the compound of lime and silica (if such had been formed during the period of seasoning), and by incorporating it with
44
flasfcyiiig — Plain and Decorative.
the mass, dispose it the more rapidlj' to consolidate. Smcaton found that well-beaten mortar set sooner and became harder than mortar made in the usual wu)-. Mortar made from hydraulic limes should be mixed as rapidly as is compatible with the thorough incorjioration of the materials, and used as soon as practicable after mixing, because if put aside for any length of time its setting properties will deteriorate.
Pure limes may be rendered hydraulic by mixing them with calcareous clays or shales, which have been so altered by the agencj- of heat that the silica they contain has to some extent assumed the nature of soluble silica. In good coarse stuff each granule of sand is coated over with the lime-paste so as to fill the interstices ; the lime-paste is to hold the granular substances in a concrete form. If too much lime-paste is present, it is called " too fat" ; if the lime-paste is deficient, it is " too lean " or " poor." This can be tested by taking uj) a portion on a trowel ; the " fat" will cling to the trowel, while the " lean " will run off like wet sand. The coarse stuff can be tested by making briquettes, and slowly drying ; the good will stand a great pressure, whereas the bad will not — in some cases falling to pieces. Some coarse stuff will appear " fat " on the trowel, but it may be the fatness of mud, not the fatness of lime, because sometimes sand is adulterated with fine-screened earth. When this stuff is made in the form of briquettes and dried, it will be extremely friable, and easy to crush ; or if put into water until soft, the earthy matter can be seen. Fine-screened earth, when dr\- and in bulk, docs not seem an objectionable material ; but in a wet state it is dirt or mud, and should be at once sent off the works. All limes increase in strength by the addition of sand, being the reverse of Portland cement, which is weakened by this addition. Mr Read made four samples of mortar with the proportions of ground lime and sand as follows: — "Ground lime mixed with 4, 6, 8, and 10 parts of clean washed sand to i part of ground lime respectively. All set and went hard. One of each was placed in water ; that made with 4 parts of sand expanded and went to pieces ; those with 6, 8, and 10 parts of sand remained whole, and continued to get harder." The addition of a small proportion of brick dust to mortar will harden and prevent the disintegration of mortar. The proportions are i part of brick dust, 2 parts of sand, and i part of lime, mixed dr\-, and tempered in the usual way.
Adhe.sive Strength. — The adhesive strength of mortar varies according to the amount of sand used. The more sand used in the mortar, the less its adhesion. The following table shows the force required to tear apart bricks bedded in mortar made with the usual proportions of sand at the end of twenty-eight days : —
Taule II. — Adhesive Strengths of Limes and Cement.s.
|
White Chalk Lime and Sand |
(I to 3) |
4J lbs. per square inch. |
|
Barrow Lias „ „ |
n |
9 » |
|
'» )> " )} |
(I to 4) |
6| , |
|
Portland Cement ,, |
(I to 4) |
23 ,. |
|
*) ) 1 |
(I to 6) |
15* >. |
The old mortar which was held in such high esteem by the Romans is said to have consisted of lime mixed with puzzolana or trass. Trass is a material similar in its nature to puzzolana, obtained from extinct volcanoes in the valleys of the Rhine, also in Holland, and is
The Hardening of Mortar. 45
largely employed in engineering works. The name " trass " is derived from a Dutch word meaning a binding substance. Much has been written and said about the ancient and the old Roman mortars, but it may be safely said that, from the year one up to the present time, no cement or mortar has the strength, or could excel, or stand our variable climate as well as Portland cement. The primary cause of the premature decay which takes place in stuccos and cements, when used externally as a coating to walls, is the presence of muddy earth and decayed animal and vegetable matter in the sand used in the lime and cement. To this may be added the frequent impurities in the limes and cement themselves. The impurities in the sand may be eradicated by thorough washing, and the lime should be carefully selected, prepared, and manipulated. John Smeaton used a mortar made of blue Lias from Aberthavv, and of puzzolana brought from Civita Vecchia, near Rome, in the construction of the Eddystone Lighthouse. If it were to be built at the present time, the cementing material would certainly be Portland cement. Having now briefly reviewed the principal parts and processes of mortar, the practical conclusions to be drawn are, that the quality of the lime is of as great importance as the quantity, and thorough slaking is imperative ; that the proportions of sand may vary considerably, and that it should be coarse and irregular in size, and of a clean and hard nature.
The Hardening of Mort.\r. — According to the results obtained from tests and e.xperience, the hardening of mortar is due to several causes acting collectively. These causes appear to be absorption of carbonic acid from the atmosphere, and the combination of part of the water with the lime which act upon the sand, dissolve and unite with some of the silica of which the sand is composed, thus forming a calcium silicate (silicate of lime). Some authorities state that the silicate of lime is formed by the reaction of lime and silicate of mortar, and to this is due the hardness of old mortar. In mortar made from pure lime, the initial setting is due to the evaporation of the water, and to the production of minute crystals of hydrate of lime, which slowly absorbs carbonic gas from the air, the rapidity of this absorption necessarily decreasing in proportion to the difficulties presented to the free access of air. The setting and hardening of hydraulic limes are due mainly to crystal- lisation brought about by the action of water on the silicate of lime, and not by mere absorption of carbonic gas from the atmosphere, as is the case in fat limes.
The Romans were convinced that it was owing to prolonged and thorough slaking that their works became so hard, and were not defaced by cracks. Alberti mentions that he once discovered in an old trough some lime which had been left there five hundred years, as he was led to believe by many indications around it, and that the lime was as soft and as fit to be used as if it had been recently made. Common mortar made of rich lime hardens very slowlj-, and only b\- the evaporation of the water of the mixture, and by the absorption of carbonic acid from the atmosphere, with which it forms a cry.stalline carbonate of lime; This process, however, is so slow, that it gave rise to the French proverb (quoted by Pasley) that " Lime at a hundred years old is still a baby" ; and there is a similar ]jroverb among Scotch masons, ''When a hundred j-ears are past and gane, then gude mortar turns into stane." Mortar from the interior of the Pyramids, where it has been e.xposed to the action of the air, still contains free lime although it is five thousand }-ears old. It has been ascertained that in rich lime mortars the carbonic acid penetrates about one-tenth of an inch into the joint in the first year, forming a skin or film which opposes the further absorption of carbonic acid, e.Kcept at a decreasing ratio, so that the lime remains soft for an indefinite period.
In illustration of this several cases have been cited, amongst others one by General Treus.sart, who in the year 1822 had occasion to remove one of the bastions erected by Vauban in 1666. After these 156 years the lime in the interior was found to be quite soft. Dr John, of Berlin, mentions
46
P/dsfcn'/zp- — P/ain and Decorative.
that in removing a jjillar t)f y feet diameter in the Church of St Peter. Berlin, eighty years after erection, the mortar was found to be quite soft in the interior.
General Fasley mentions several instances at Do\er Harbour, and at Chatham dockjard, the latter in particular, when part of the old wharf wall was pulled down in the winter of 1834. The workmen were obliged to blast the brickwork fronting the river, which had been built with Roman cement, but the backing, done with common lime mortar, was in a state of pulp ; the lime used had been i)rcpared from pure limestone or chalk. But it is not necessary to go so far back for knowledge of the absence of the setting quality in the rich limes, as there have been frequent experiences of it in the present age. While these remarks are true of the richer limes, man>- of our limes are comparatively poor in carbonate, and associated with silica, alumina, magnesia, and oxide of iron, which may either be partiallj- combined in the natural state, or enter into combination with the lime during the jsrocess of calcination, and these limes might be termed slightij' h>-draulic.
M. Landrin, who submitted to the French Academy the results of some experiments on the hydraulicity and hardening of cements and limes, came to the conclusion that (i) silicates of lime raised to high temperature set with difficulty, and in any case do not harden in water; (2) for the calcination of cements to exert a maximum influence on the setting, in connection with water of the compound obtained, the process must be carried sufficiently far for the limes to act on the silica so as to transform it into hydraulic, and not into fused silica ; and (3) carbonic acid is an indis- pensable factor in the setting of siliceous cements, inasmuch as it is this substance which ultimatel}- brings about their hardening. The comparative strengths of various mortars are shown in the following table : —
Comparative Strength of Grey Lime
Table III.
and Portland Cement Mortar, also I'ortland Cement Mortar with the addition of Lime and Mortar.— Redcr.WE,
|
No. |
No. of T»ts. |
Proportions. |
Breaking Strain on s.23 square inch in lbs. |
Breaking Weight per square inch in lbs. |
Ratio as compared with Lime Mortar. |
Ratio as compared with Cement .Morlar. |
RE.MARKS. |
|||
|
Sand. |
Cement. |
Lime. |
Water. |
|||||||
|
I |
17 |
3.00 |
... |
1. 00 |
1-33 |
61.06 |
27-13 |
... |
Three samples. |
|
|
2 |
27 |
2.00 |
1. 00 |
1-33 |
106.07 |
47.09 |
Grey lime. |
|||
|
3 27 |
2.00 |
... |
1. 00 |
'•33 |
82.00 |
36.44 |
_ |
... j |
Water includes that required for slaking lime. |
|
|
' '5 |
6.00 |
1. 00 |
... |
1.25 |
233-53 |
'03.79 |
2. Si to I |
|||
|
2 |
20 |
8.00 |
1. 00 |
... |
1.66 |
1 54.80 |
68.80 |
1.86 to I |
? |
Cement taken from bulk in store. |
|
3 |
35 |
10.00 |
1. 00 |
... |
2.00 |
112.88 |
50.16 |
1.36 to I |
J |
|
|
1 70 |
6.00 |
1. 00 |
0.50 |
i.So |
165.31 |
73-47 |
2.00 to I |
0.70 to 1 1 |
||
|
3 |
74 |
8.00 |
1. 00 |
0.66 |
2.00 |
132.62 |
5894 |
1.60 to I |
0.S5 to I , |
Water includes that required for slaking lime. |
|
3 |
85 |
10.00 |
1. 00 0.83 Loain. |
2.50 |
95-2- |
42.34 |
1.14 to I |
0.84 to I ; |
||
|
1 |
21 |
6.00 |
1. 00 0.50 |
1. 00 |
136.80 |
60.80 |
1.64 to I |
0.58 to 1 |
||
|
2 |
25 |
8.00 |
\ 1. 00 0.66 |
'•33 |
86.48 |
38.43 |
1.04 to I |
1 0.55 to I |
Yellow loam, fresh dug, and rather damp. |
|
|
3 |
.9 |
10.00 |
1. 00 0.S3 |
2.00 |
64.50 |
2S.66 |
0.77 to I |
0.57 to 1 |
Magnesia in Mortars. 47
Magnesia in Mortars. — Magnesia plays an important part in the " setting " of hydraulic h'mes as well as in Portland cement. Yicat, after many experiments, was led to recommend magnesia as a suitable ingredient of mortars to be immersed in the sea, stating that if it could be obtained at a cost that would admit its application to such purposes, the problem of making concrete unalterable by sea-water would be solved. General Gillmore, speaking of the American lime and cement deposits, says : " Magnesia plaj-s an important part in the ' .setting ' of mortars, derived from the argillo-magnesian limestones such as those which furnish the Rosendale cements. The magnesia, like the lime, appears in the form of a carbonate. During calcination, the carbonic acid is driven off, leaving protoxide of magnesia, which comports itself like lime in the presence of silica and alumina, b>- forming silicate of magnesia and aluminate of magnesia. These compounds become hydrated in the presence of water, and are pronounced by both Vicat and Chatoney to furnish gangues, which resist the dissolving action of sea-water better than the silicate and aluminate of lime. This statement is doubtless correct, for we know that all of these compounds, whether in air or water, absorb carbonic acid, and pass to the condition of subcarbonates, and that the carbonate of lime is more soluble in water holding carbonic acid, and certain organic acids of the soil in solution, than the carbonate of magnesia. At all events, whatever may be the cause of the superiority, it is pretty well established by experience that the cements derived from argillo-magnesian limestones furnish a durable cement for construction in the sea."
In Marshal Vaillant's report to the French Academy of Sciences, from the Commission to which Chatoney and Ri\ot's paper was referred in 1856, this superiorit}- of the magnesian hydrates is distinctly asserted. A few years ago the French Government Office of Civil Engineers made a series of comparative tests on three samples each of French, English, and German cement, in which the results are given in favour of the German cement, which contained magnesia to the extent of 2.4 per cent., against 0.26 in the English and 0.32 in the French, and summed up thus : " A great value is to be placed on the presence of magnesia, and the excellence of the German cement is partly due to the higher percentage of magnesia contained in it." Gillmore further says that magnesian limestone furnishes nearly all the hydraulic cement manufactured in the western part of the State of New York. At East Vienna it has been used for cement, and at Akron, Erie Co., X.Y., a manufactory of some extent is in operation. Vicat says : " Having analysed several old mortars, with the view of discovering, if possible, to what their superior durability might be attributed, I found, in some excellent specimens of very old mortar, magnesia to exist in consider- able proportion." The limestones, therefore, from which these mortars were prei:)ared must have contained the silica and magnesia as constituent ingredients ; and it is to be remembered that it is the presence of these substances which communicates the property of hardening under water. Professor Scorgie says of carbonate of magnesia : " Magnesium carbonate is a substance very similar to carbonate of lime ; it loses its carbonic acid in burning, combines with silica, &c., and behaves generally in the same way ; it does not slake, howe\er, on being wetted, but combines with the water gradually, and quietly sets to some extent in doing so. Magnesium carbonate, combined with lime, reduces the energy of the slaking, and increases that of the ' setting ' processes ; when other substances are present, its beha\iour and combination with them are similar to those of lime. When carbonate of magnesia is pre.sent in sufficient quantitj-, say about 30 per cent., it renders lime hydraulic independently of and in the absence of clay." Colonel Pasley also, bj- experiments, demonstrated that magnesian limestones are suitable for hydraulic mortars.
The foregoing assertions that magnesium carbonate, combined with lime, reduces the energy of the slaking and increases that of the " setting " processes are satisfactory and conclusive. Many
4^ Plastering — Plain a//ti Decorative.
sucli evidences showint; the \alue of magnesia in hydraulic mortars miylit be quoted, but perhaps these are sufficient.
Ekkects of Salt and Frost in Mortars. — Few experiments have as jet been made to test the general effects of salt in mortars, though as a prcvcnti\c of the effects of frost it has been tried with varj-ing results.
In some German experiments, designed to ascertain the effect of frost upon hj-draulic limes and cement gauged with and without the addition of salt to the water, cubes of stones were joined together with cement mixed with water ranging from pure rain water to water containing from 2 to 8 per cent, of salt. Before the cement was set. the blocks were exposed in air at a temperature varying from 20 to 32 degrees Fahr., after which they were kept for seven da\-s in a warm room. At the end of this time the samples were e.xamined. The cement made with water was quite crumbled, and had lost all its tenacity. The cement made with water containing 2 jser cent, was in better condition, but could not be described as good ; while that containing 8 per cent, of salt had not suffered from its exposure to the lowest temperature available for the purpose of experiment. It is suggested as possible that the effect of the salt was merely to prevent the water in which it was dissolved freezing at the temperature named, and so permitted the cement to set in the ordinarj- way. But it must be allowed that in practice, salt dissolved in the water for mixing mortar has been successfully u.scd to resist the effect of frost. A solution of salt applied to new plastered walls in the event of a sudden frost will protect the work from injurj-. The addition of a small portion of sugar will improve its adhesion, and increase the frost-resisting pov/ers.
Salt takes up the vapours from the atmosphere, causing the work to show efflorescence, and in some instances to flake, especially in external w nrk. That some engineers believe there is virtue in salt water is beyond doubt, because salt water has been named in their specifications for the gauging of concrete. Salt in Portland cement seems to act somewhat differently ; as regards efflorescence it shows more in this material than in lime mortar. Salt should not be used in Portland cement work that has to be subsequently painted. According to the results of tests of mortar used for the exterior brick facing of the Forth Bridge piers below water they show a good average tensile strength. One part of Portland cement and one part of sand were slightly ground together in a mill with salt water, and briquettes made from this gauge gave an average of 365 lbs. per square inch at one week, and 510 lbs. at five weeks after gauging. It would be interesting to note the condition of this mortar a century hence, time being the trying test for all mortars.
A solution of commercial glycerine mixed with the setting stuff, or used as a wash on newly finished lime plaster work, is a good preventive of the evil effects of frost. Glycerine solution may also be used for the same purpose on new concrete paving. Strong sugar water mixed with coarse stuff has some power in resisting frost. The quantity depends upon the class of lime, but the average is about 8 lbs. of sugar to i cubic yard of coarse stuff or setting stuff The sugar must be dissolved in hot water, and the stuff used as stiff as possible.
Sugar with Cement. — Sugar or other saccharine matter mixed with cement has been tried with varying success. It is well known that saccharine is u.sed with mortars in India. According to some experiments made in America, the results obtained were that the addition of sugar or molasses delayed the setting of the mortar, the retardation being greater when molasses were used. When certain proportions were not exceeded, the strength of the mixture was that of the pure cement. Less than 2 per cent, of sugar must be added to Portland cement, and less than i per cent, to Roman, otherwise the mortar will not hold together. The sugar appears to have no chemical action on the other materials, crystals of it being easily detected on the broken surfaces.
Sugar ill Cements and Mortars. 49
the increased binding power of the cement brought about by the addition of sugar being due more to mechanical than chemical causes. In my own experiments with sugar added to Portland cement for casting deep undercut ornament figures and animals out of gelatine moulds, the results at first were very irregular, some casts attaining great hardness, while others crumbled to pieces. The time of setting also varied considerably. Three different brands of cement were used, and it was found that the cement containing the most lime required more sugar than the lowest limed cement, but the average is about li per cent, of added sugar. The sugar must be dissolved in the water used for gauging. The setting and ultimate hardness is also influenced by the atmosphere. The casts should be kept in a dry place until set and dry, before exposing them to damp or wet. Portland cement has a tendency (especiallj- if over limed) to "fur" gelatine moulds, but the sugared cement left the moulds quite clean.
In experiments b_\- Austrian plasterers, mi.xtures of i part of cement and 3 parts sand, and 10 per cent, of water, and of pure cement with as much water as was necessary to give the mass plasticity, were prepared. From i to 5 per cent, of powdered sugar was well mi.xed with the dry cement. The cement used was of inferior quality, the sand being ordinary building sand, and not the so-called "normal " sand, which is of a superior qualit}-. They were left to harden in a dry' place, and not underwater. For each series of samples made with sugar a comparative series without sugar were prepared, all the samples being made by the same man, under the same conditions, and with the same care. The tenacity was ascertained by Kraft's cement-testing machine. The strength was far below that prescribed and generally obtained. It should be mentioned that the samples with sugar (especially those of pure cement) showed a strong tendency during the first twenty-four hours to combine intimately with the smooth china plate on which they were placed to swell, and the results of the trials showed that with mixtures of cement and sand, and by hardening in a dry place, the binding effect may be increased b)- the addition of sugar, which reached its maximum with from 3 to 4 per cent, of sugar added. With pure cement the binding effect was not much increased. I think if the sugar used for gauging had been dissolved, and not mixed drj-, the results would have proved better.
Sugar in Mortar. — Most writers have supposed that the " old Roman mortars " contained strong ale, wort, or other saccharine matter, and it is probable that the use of sugar with lime passed from India to Egypt and Rome, and that malt or other saccharine matter was used in their mortars. The addition of sugar to water enables it to take up about 14 times more lime than water by itself. The following is an extract from the Roorkee : " It is common in this country to mi.x a small quantity of the coarsest sugar, ' goor,' or 'jaghery,' as it is termed in India, with the water used for mixing up mortar. Where fat limes alone can be produced, their bad qualities may in some degree be corrected by it, as its influence is very great in the first solidification of mortar. This is attributed to the fact that mortars made of shell lime have stood the action of the weather for centuiies owing to this mi.xture of 'jaghery' in their composition. Experiments were made on bricks joined together b\- mortar, consisting of i part of common shell lime to lA of sand ; i lb. of 'jaghery ' being mixed with each gallon of water. The bricks were left for thirteen hours, and after that time the average breaking weight of the joints in twenty