172 PHILOSOPHICAL TRANSACTIONS. [ANNO 1782. 



went on gently and gradually; but on adding 20 drops more of nitrous acid, the 

 solution was greatly promoted, and by subjecting it to a proper degree of heat, 

 the whole portion of gold leaf was dissolved. This shows, he thinks, the dif- 

 ference between this acid and the muriatic acid; for 2 parts of smoking muriatic- 

 acid and 1 part of aqua-fortis will not, he says, dissolve gold, especially if a di- 

 gesting heat be not applied. Hence he infers that the acid of fat is entitled to 

 be classed with the stronger acids. 



Exper. 79- Calx of platina, precipitated by salt of tartar from its solution in 

 aqua regis, being treated in the same manner (exper. 76) was dissolved. One 

 portion of the filtrated solution gave a dark coloured precipitate with Beguin's 

 tincture, which when collected on a filtre and dried, was of a yellowish brown 

 colour. The other portion of the solution being evaporated, yielded oblong yel- 

 lowish brown crystals, in much greater quantity than the solution of gold 

 had done. 



Exper. 80. Silver leaf was slightly corroded by the acid of fat. By continued 

 digestion the calx of silver was dissolved by it. 



Exper. 81. It exerted but little solvent power over quicksilver in its metallic 

 state; but 



Exper. 82. Calx of quicksilver, obtained by means of salt of tartar from cor- 

 rosive sublimate, was read''}' dissolved by the acid of fat, even without the assist- 

 ance of heat. The solution being subjected to distillation, towards the end of 

 the operation, when the heat was increased, a white sublimate attached itself to 

 the neck of the retort. Dr. C. remarks that the acid of fat is the only acid, ex- 

 cepting the muriatic acid, which gives a dry sublimate with quicksilver; and what 

 is singular, this sublimate is volatilized at a lower degree of heat than the muri- 

 atic sublimate of quicksilver. 



Exp. 83. It dissolved copper, even when not assisted by heat ; but more 

 readily when subjected to digestion. The solution yielded crystals which deli- 

 quesced in the air. 



Exp. 84. The solution of iron had an astringent taste ; it yielded needle-like 

 crystals, which scarcely attracted moisture from the air. 



Exp. 85. Lead, in its metallic state, was rather corroded than dissolved by 

 this acid ; but it readily dissolved minium, and the solution yielded crystals, 

 which had a sweetish taste. 



Exp. 86. It dissolved regulus of antimony with the assistance of heat. The 

 evaporated solution yielded crystals which did not deliquesce in the air. 



Exp. 87. Zinc was readily dissolved. The solution had a strong metallic taste, 

 and on adding salt of tartar, it let fall a white sediment, which (like the flowers 

 of zinc) turned yellow on exposure to flame. 



Exp. 88. Tin-tilings were readily acted upon by this acid, and were converted 



