JOURNAL 



OF 



NATURAL PHILOSOPHY, CHEMISTRY, 



THE ART S. 



SUPPLEMENT to VOL. XllL 



ARTICLE L 



Oa the Saline Effiorefcences upon Walls; Salirarj/ Concretions ; 

 Deflagration of Mercury by Gulvanifm ; Biliary Calculi; and 

 the freezing Point of Spermaceti. 5j/ John Bostock, M. D. 



To Mr. NICHOLSON. 

 SIR. 



J.N the third and fixth volumes of your Journal you have Jn- Examinaeion of 

 ierted an account of fome experiments that I performed on the '^p'*' ^^<^™«"s 

 faline efflorefcences found upon walls. I have lately had an found upon j 

 opportunity of examining two other fpecimens, of which I^^^'^* 

 now fend you the particulars. The firft was obtained in con- 

 fiderable quantity from the inner w^alls of a warehoufe that 

 had been ereded about twenty years. By a feries of fimple The firft was 

 experiments, which it is unnecefTary to detail at full length/'^f ^^'^ ''^ ^"^'* 

 I found it to be a fulphale of foda, which, as in the former 

 cafes, feemed to exift in a ftale of almoft perfe6l purity. The 

 circuraftances attending the fecond of tbefe efflorefcences 

 were more lingular. It was given me by a friend who had 

 fcraped it from off the ftones which are fituated on the infide The fecond was 

 of the weft aifle of York Minfter* My friend, on whofe ac- f"3pe=i from the 

 Vol. XIII. — Supplement, Dd curacy 



