Metallic Ojoides and Salts in Muriate of Ammonia, 179 



cause by which such solution is effected. From the general 

 tenor of the paper it is evident that Mr. Brett supposes, that 

 when a metallic oxide or salt is dissolved in a solution of mu- 

 riate or nitrate of ammonia, no decomposition takes place, and 

 that the metallic oxide or salt is merely, as he expresses it, "dis- 

 solved by the muriate or nitrate of ammonia." This, however, 

 is by no means a correct view of the case ; for on repeating a 

 few of the experiments proposed by Mr. Brett, I find that 

 when a solution of muriate of ammonia is boiled with any of 

 the under-mentioned metallic oxides or salts, viz. 



Protoxide of mercury, peroxide of mercury, red oxide of 



mercury by nitric acid, protoxide of lead, protocarbo- 



nate of lead, oxide of zinc, carbonate of zinc, peroxide 



of copper, and subnitrate of bismuth, 



a very free evolution of ammonia takes place, and a metallic 



chloride is formed, which combines, in some instances, with 



part of the muriate of ammonia, forming a triple salt. The 



theory of this process is too simple to require an explanation. 



I have not performed any other of Mr. Brett's experiments, 

 but deem the hvf I have thus briefly detailed, sufficient data 

 from which to infer that decomposition occurs in almost every 

 instance ; for although it may be difficult to prove that phos^ 

 phate of ammonia and muriate of lime are formed when phos- 

 phate of lime is dissolved in muriate of ammonia, yet analogy 

 favours such an opinion. The inefficacy of nitrate of am- 

 monia when contrasted with the muriate may be ascribed to 

 the trifling affinity existing between nitric acid and the metallic 

 oxides when compared with the attraction of their metals for 

 chlorine. 



I have no doubt that on a repetition of his experiments 

 Mr. Brett will find ample reasons for changing his present 

 idea, for when large quantities, as two drachms, are operated 

 on at once, no better test than the nose is requisite for deter- 

 mining the presence of the ammonia evolved. 



I am. Gentlemen, yours, &c. 



Roebuck Place, Great Dover Road, Lewis Thompson, 



Feb. 6, 1837. M.R.C.S. 



Errata in Vol, ix. — In the heading of my paper, p. 442, 

 for " lodous Acid^^ read " Iodic Acid ;" and in the same page, 

 line 19, for "2^ atoms or 295 grains of recentlif precipitated 

 oxide of silver" read " 5 atoms or 590 grains", &c. 



Dec. 20, 1836. 



2 A 2 



