\J4 PHILOSOPHICAL TRANSACTIONS. [ANNO 1782. 



regis, an orange-coloured precipitate was thrown down. This precipitate heing 

 edulcorated and exsiccated, it became of a yellowish grey colour, and was much 

 less deliquescent than the precipitate from gold. 



Exp. Q6. Silver. The acid of fat being added to a solution of silver in nitrous 

 acid, a grey-coloured precipitate, inclining somewhat to red, was obtained. 



Exp. Q7- Quicksilver. This metal was precipitated from its solution in 

 nitrous acid by the acid of fat. But, what is very remarkable, when this acid 

 was added to a solution of corrosive sublimate; in a short time the solution be- 

 came milky, and deposited a white powder. This effect takes place sooner if 

 the mixture be subjected to a digesting heat. Dr. C. thinks that this may serve 

 as a test by which the acid of fat may be distinguished from other acids, and 

 particularly from the muriatic acid. This white precipitate being washed and 

 afterwards dissolved with the assistance of a digesting heat, in water, a piece of 

 copper was whitened on being thrown into it. The evaporated solution gave a 

 white residuum, which did not deliquesce in the air. 



Exp. 98. Lead. The precipitate from a nitrous solution of lead, had the 

 appearance of small needle-like crystals, which being edulcorated, were readily 

 dissolved in water, subjected to a digesting heat. The evaporated solution gave 

 a powder which was but little deliquescent. 



Exp. 99. Bismuth. The nitrous acid used for dissolving this metal, had 

 been so much diluted, that when the solution was ended, a fresh addition of 

 water occasioned no precipitation. But as soon as some drops of the acid of fat 

 were added to the solution, a white powder was- thrown down. This being 

 washed and dissolved in water with a digesting heat, and the solution being after- 

 wards filtrated and evaporated, a white residuum was obtained, which was very 

 deliquescent. 



Exp. 100. Regulus of sfntimony. To a saturated solution of this metal in 

 aqua regis, distilled water being added, it became turbid ; after this was filtrated 

 a fresh addition of water produced no further change in it ; but when some of 

 the acid of fat was poured into it, a white precipitate was immediately let fall, 

 which was for the most part soluble in water; from which, by evaporation was 

 obtained a residuum which attracted moisture from the air, and shot into small 

 crystals. 



Exp. 101. Tin, was precipitated from its solution in aqua regis by this acid. 

 The precipitate was of a yellowish brown colour. Being washed and digested 

 with water, it yielded a white salt, which was very deliquescent. 



Exp. 102. Copper. No precipitate was obtained either from vitriolated copper 

 or nitrated copper, by admixtion with the acid of fat. 



Exp. 103. Iron. Nor from nitrated or vitriolated iron. 



Exp. 104. Zinc. Nor from nitrated or vitriolated zinc. 



