33i Mr. Brett^ sjurt/ier Ji„vpenments on the 



not the subject of my inquiry; to find fault with the expression 

 is therefore, I think, rather liypercritical, as it would be in the 

 common expression that certain metallic bodies, such as zinc 

 or silver, are soluble in nitric acid; for any one using such a 

 term in reference to those substances would doubtless know 

 that before such solution could take place, the acid must un- 

 dergo decomposition. The experiments which I performed, 

 as well as a repetition of those referred to in my last paper as 

 instituted by M. Vogel, and afterwards by Mr. Smith, could 

 not but have informed me of the fact that the ammoniacal salt 

 does under certain circumstances, if not in all cases, suffer de- 

 composition. 



1 shall now briefly mention the results of my late experi- 

 ments on this subject. The oxides and salts operated upon 

 were well washed on filters with distilled water, and allowed 

 to dry at the temperature of the room. 



BaryticSalts, — The carbonate and phosphate of baryta, when 

 digested in cold muriate of ammonia in solution (a saturated 

 solution), yield a fluid which, after filtration, contains the earth 

 in some form of combination, it being readily precipitated by 

 dilute sulphuric acid: ammonia in excess causes no precipitate. 



Strontian Salts, — Precisely the same results were obtained. 



Lime Salts, — The neutral phosphate of lime which possesses 

 a semi-crystalline appearance, and was obtained by adding a 

 neutral solution of phosphate of ammonia to a solution of 

 chloride of calcium in excess, as also the subphosphate, al- 

 together devoid of crystalline structure, and obtained by add- 

 ing an excess of the salt of lime to the phosphatic salt, con- 

 taining, according to Berzelius, 1 and ^ more lime than the 

 neutral salt*, when digested in the cold with the saturated so- 

 lution of muriate of ammonia, yielded by filtration a fluid 

 which was abundantly precipitated by oxalate of ammonia, 

 and therefore contained lime in some form of combination. 

 It may be observed that ammonia added in excess to the fil- 

 tered fluid obtained by digesting any of the above salts, 

 barytic, strontian, or calcareous, did not cause any precipi- 

 tate. 



Magnesian Salts. — The carbonate and ammoniaco-magne- 

 sian phosphate are similarly acted upon. 



Oxide and Salts of Cadmium. — The oxide, carbonate, phos- 

 phate, and oxalate ofcatlmium, when digested in a cold satu- 

 rated solution of muriate of ammonia, yielded a fluid by filtra- 

 tion, abundantly precipitated of a yellow colour by hydrosul- 

 phuret of ammonia. 



Salts of Cobalt, — The carbonate and phosphate when di- 



* Berzelius, Traitc de Chbnic, torn. iv. p. 71 et scq. 



