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THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[January, 



state in which every part of Sir C. Wren's Church was found, after standing 

 about 170 years, has fully borne out his argument. The tower of the 

 church was built in a very superior manner, with thicker walls of flint aud 

 chalk. 



Mr. T. W. Papworth exhibited a volume containing a collection of deco- 

 rations or a chapel in the Cathedral at Lisbon, made at Rome in 1755. It 

 appears, from these drawings, that the architect sent his general designs to 

 Rome, and that the details were there filled up by the most eminent decora- 

 tive artists. The name of Pompeio Battoni, who was to supply some paint- 

 ing of the higher class, occurs among the number. There are designs for the 

 pavements, railings, hangings, and every description of decoration and fur- 

 niture to make the work complete. The artistical knowledge displayed in 

 these drawings throughout the variety of operations necessary to carry out a 

 work of this kind, and the unity of purpose with which it is brought together 

 and applied, is what is principally deficient in our modem system of architec- 

 ture. 



December 18, 1843.— W. Tite, Esq., v. p., in the Chair. 



The following communication was read from Mr. Benj. Ferrey, Fellow, 

 on Mr. Silvkster's " Process for repelling moisture from external watts " 



It will be in the recollection of many members of the Institute, that Mr. 

 Sylvester, at a meeting during the hist session, directed attention to the dis- 

 covery of a process by which bricks might be made impervious to moisture, 

 and exhibited some experiments, placing bricks of a very porous description 

 which had been Subjected to the process, into water, allowing them to he 

 immersed' for some time, and showing, when taken out of the water, tli.it 

 they had imbibed no moisture. These experiments, at the time, were con- 

 sidered satisfactory, and the cheapness and ease attending the application 

 to the process, were strong recommendations in its favour. 



It happened dining last summer, that I was called upon, in a distant part 

 of Dorsetshire, to suggest some means by which the wet might he prevented 

 from penetrating the external walls of a school-house that had n O ntlj bl en 

 built in a very substantial manner, with bricks of the best quality; but 

 where, owing to the elevated and exposed position of the building, it was 

 found that neither increased thickness of walling, nor internal battening would 

 answer, to make the school habitable, and nothing but an external coating of 

 cement, was by the proprietor of the building, thought capable of remedy ing 

 so serious an evil. 



It occurred to me that this was a good opportunity of testing the merits of 

 Mr, Sj Ulster's recommendation, and, it being a favourable period of the year 

 fur external colouring, I ordered the operation to he commenced, availing 

 myself of the services of a clerk of the works, whom I had in the neighbour- 

 hood, to see that the liquids were carefully and properly applied. 



1 shuuM mention that the walls of the school-house were built of kiln- 

 burned bucks from a village called Broad-mayne, will known as supplying 

 tin- bcsl bricks in Dorsetshire: in situations protected from the sevn 

 of south-west storms, these bricks are found to be proof against the ordinary 

 effects of weather, but in many hilly parts of Dorsetshire, nothing but the 

 most compact and indurated material will resist the violence of the tempests, 

 anil I have remarked hew many ancient brick building, with stone dressings, 

 have, in various parts of this country , been disfigured by coatings of cement 

 or blue lias. This practice has evidently been resorted to, as the general 

 cure wherever the wet penetrated the walls, and it would have been adopted 

 in the present case but for my interposition. 



As it is probable tli.it main Gentlemen may he present when this letter is 

 read, who were not at the Institute when Mr. Sylvester described the mate- 

 rials of his solutions, I will state how they were composed by us, in accord- 

 ance with Mr. Sylvester's directions. 



The ingredients were mixed in the following proportions: — | lb. of mottled 

 soap to 1 gallon of water. This composition, when in a boiling state, was 

 laid over the surface of the brickwork steadily and carefully, with a large flat 

 brush, so as not to form a froth, or lather on the surface. 



This wash was permitted to remain 24 hours to become dry and hard. 



Another mixture was then made in these proportions: — i, lb. of alum to 4 

 gallons of water, which, after standing 12 hours, in order that the alum 

 should be completely dissolved, was then applied in like manner, with aflat 

 brush over the coating of soap. I need scarcely mention, that we availed 

 ourselves of settled and dry weather during July, for these operations. 



I have now to speak of the result up to the present time, as to the success 

 of the process. Within a month after the trial, there happened one of those 

 tremendous SOUth-west gales, accompanied by heavy, driving rain, such as 

 had formerly drenched the school-bouse, and obliged the inmates to put pails, 

 cloths, &c, to catch the drippings inside. It is satisfactory to state that the 

 walls were completely proof against the rain ; not a drop penetrated through, 

 during 48 hours of the most severe weather, nor from that time to the pres- 

 ent, though repeatedly subjected to like trials, have the walls admitted the 

 least moisture, nor has the artificial coating suffered apparently the slightest 

 injury. 



The liquid when applied, formed a complete thin scaly, or gummy look- 

 ing integument, perceptible only upon close inspection, causing no discolor- 

 ation, but producing rather a mellow appearance, such as a building obtains 



when covered with lichens ; the rain splashes against the walls as against 

 glass, and runs down the face in a similar manner. 



Upon communicating to Mr. Sylvester, this satisfactory result, I was glad 

 to hear from him of other useful purposes to which this simple process has 

 been applied ; at the same time I learnt that about ten years since he advised 

 this method to be applied to the north front of a stone-building near London, 

 where the damp and discoloration were very offensive. His suggestion wa9 

 attended to, and with complete success. 



It certainly appears to be a simple, cheap, and useful discovery, performing 

 its purpose without discolouring the material on which it is laid, and being 

 therefore unobjectionable on this account. Although from the nature of 

 the thing, it may be more frequently wanted for brickwork, it is said to be 

 equally effective on stone, for precisely in the same degree that the structure 

 of the stone admits moisture through its imperfect formation, will it receive 

 that solution ; so that the pores or vesicles on the face of the stone became 

 filled with insoluble particles,. — it is therefore immaterial whether the stone 

 be of lime, sand, or oolitic formation. The value of a process which may 

 give an indurated surface to many kinds of stone that before were unfit for 

 building purposes, by reason of rapid disintegration under the effects of wet 

 and frost, will be duly appreciated by the architect, and though it may be 

 hazardous to use at once material;, of doubtful quality, relying upon this 

 remedy, yet it is a subject quite worthy of our best attention, and I think it 

 right to mention what has been told me in reference to this most important 

 object. 



From the perfect success which attended experiments in other parts of the 

 country similar to what I have described, the County-Surveyor of Kent mads 

 a bold trial of the process. 



A block of the Cation or Reigate stone, when taken from the quarry in its 

 green and soft state, was worked into a cistern to contain water, and after 

 becoming hardened and dry by the exposure to the atmosphere, it was well 

 covered all over, both within ami without, by the wash of soap and alum ; 

 this being properly done, it was at once filled with water, and used for the 

 ordinary [mi poses of a leaden cistern; this was done about three years since, 

 and the cistern is now in use, never having leaked in the slightest degree 

 from the day it was fust used, although exposed through the winters, with- 

 out any protection whatever. 



Perhaps no substance could put the process to a severer proof, than Gatton 

 stone: — It is described in the Parliamentary Report of the Commissioners, 

 as composed of fine siliceous grains, with a calcareo-silicious cement, contain- 

 ing green silicate of iron, and plates of mica. It is a stone that will not 

 stand the weather, and though it has in former times been much used, all 

 the exposed portions of such edifices, are destroyed. 



I have had some experience of the unfitness of this stone for building, 

 having used it, at the strong solicitation of an employer, and against my own 

 conviction, in some court halls and external screenvvork, and where, within 

 two years after its use, the greater portion bad split and become shattered, 

 from the effects of frost. 1 need scarcely say, that it was near to the 

 Gatton quarries, and that its cheapness was the recommendation in the eyes 

 of my employer. 



Any composition for the preservation of stone, having a lasting effect, must 

 he most valuable. It is true that nothing but time can prove whether the 

 effect is permanent ; this difficulty attends ail schemes. It is an argument 

 employed to depreciate the use of those processes by which timber is pro- 

 tected from decay, and it is an objection which, if permitted to operate too 

 strongly, may go far to discourage scientific men from directing their ener- 

 gies to most important purposes. 



It would indeed be a great point gained, if the architect, by the use of a 

 simple chemical solution, superficially applied, to protect the external faces 

 from the effecis of weather (for it is obvious that decay occurs chiefly upon 

 the exposed surfaces,) could employ stone, extensively to be met with in dif- 

 ferent parts of the country, but which, at present, he dare not use. from the 

 established fact of its early tendency to decay, — thus, the Tottcnhoe, Rei- 

 gate, the Chinch, the Malm Hock, and other formations, though suited 

 for internal work, are utterly unfit to be used out of doors. It would not be 

 difficult to enumerate a great many more kinds of stone prohibited at present. 

 1 have alluded particularly to this, because it is a favourite notion of Mr. 

 Sylvester's, that these stones may be brought into use with a certainty of 

 their durability if they are subjected to the process which so effectually 

 secures bricks. 



Both oil and hees'-wax are much used even now to stop the pores, when 

 there is a suspicion that the stone not being sufficiently seasoned, may he 

 shattered by the frost, it is however obvious that such applications can only- 

 serve a very temporary purpose. It is to the contact of two soluble ingre- 

 dients whereby a new and insoluble chemical substance is produced, that we 

 can reasonably look for important results. 



There is no inherent cause for decay in either stone or brick ; two blocks 

 of stone from the same quarry, but from different parts, will be equally sound 

 for building purposes, secured from weather; but the same pieces, if placed 

 side by side on the south west side of a building, would be very differently 

 affected, and one might speedily exhibit a rotten tendency, when the other 

 would stand sound. 



If stone or brick contain within itself substances which, by chemical 

 agency, could destroy their structure, it might seem a hopeless matter to 

 devise a preparation for the surface that could stop such natural disruption, 

 or if it were ascertained that either of these materials exuded moisture, 

 from saline particles forming part of their substance, whereby the action of 



