STUCCO FOR PRESERVING STONE. |<J 



Lastly, this matter yielded no appreciable quantity of No aJumsae, 



alumine, so that,jt may be pvesumed no alum was employed 



in the composition. 



Mr. Bachelier having some of the paper that had been AntilysKrftiit 



prepared by his father, the coating of this was analysed, and P^9^ coaiicg. 



the result indicated, that 



Quicklime 56'65 



Calcined gypsuin-... ..i ••••••-• »••• 23'34 



Ceruse or carbonate of lead • 20 



had entered into its composition. 



On these proportions more dependance can be placed This mo^ ^ 



than on the former, since it was impossible to detach the ^^ *^'^P*^"'^ 



oa. 

 plaster from the pillars without some of the substance of the 



stone itself. 



That the caseous part of the milk is the proper vehicle for Chae^j- masi-er 

 the powders we learn from the positive testimony of Mr. Ba- \'® ^^ '**' 

 chelier, the son; and its utility is confirmed by the experi- 

 ments of Mr. d'Arcet published some years ago*. 



Of the efficacy of Mr. Bachelier's composition there can EfHcacy ofAe 

 be no doubt, as we have irrefragable and still existing testi- ^u^SXtir" 

 mony of it; nor would it be difficult to estimate this before- 

 hand, when we consider the causes, that produce the gradual 

 decay of the finest buildings in this capital, and the means 

 of guarding against them. 



Hard and fine grained calcareous stone, susceptible of a Stone not la- 

 greater or less degree of polish, is not liable to this altera- ^^J^^^^ ^^ ^ 

 tion. It is therefore owing to the nature of the stDne com- 

 monly employed, which is of a loose and unequal texture, and liaWe to it, 

 filled with cavities, and found by analysis to contain 10 or 

 12 per cent of silex, and frequently 3 or 4 of oxide of iron. 

 The difference of the stones from the quarries near Paris is 

 evident from the tables of Mr. Rondelet, in bis Treatise on 

 the Art of Building; where we see, for example, that what 

 is called the grignard of Passy is of the specific gravity of 

 2*462, and supports a weight of 6750 kil. ; while the /aw- 

 bourde of St Germain has only 1*560 sp. grav., and is 



* D6c. phil. an X, No. 5. The- pamphlet entitled PArt de peindre 

 «tt Fromagef ou en Ramekin, which Mr. d'Arcet regrets his being unable 

 to procure, was foreign to ihe subject, as it related to patiiting with soap 

 of w»x. {See Journal, Voi. 1, p.ili.'} 



crushed 



