1818.] Oxide of Silver in Ammonia. 13 



is of no consequence, except in attempts to detect hydrogen in 

 the diamond ; the inconvenience may be obviated, if required, 

 by using the flame of carbonic oxide. As, however, no hydro- 

 gen has at any time been detected in the diamond, it is better 

 to use that gas as the heating agent; for then the carbonic 

 acid, produced by the combustion, is unmixed with that from 

 any other source, and may be collected, and its quantity ascer- 

 tained. 



On the Solution of Silver in Ammonia*. 



THE ease with which the compounds of silver are dissolved 

 by ammonia, and the frequent formation of powerfully de- 

 tonating and dangerous substances in these solutions, are well 

 known. I have been induced to examine some of the phe- 

 nomena presented by these bodies, and perhaps an account of 

 what is, I believe, original, may not be unacceptable as an 

 addition to the scanty stock of information published on this 

 subject. 



When the oxide of silver, precipitated either by the alkalies 

 or alkaline earths, is put into solution of ammonia, it is entirely 

 dissolved, producing a pale brownish solution. If this solution 

 be exposed in an open vessel, a brilliant pellicle forms on its 

 surface, which, when removed, is succeeded by another and 

 another, until most of the metal is separated. 



This, which is an oxide of silver, was noticed long ago by 

 Berthollet in the ' Annales de Chimie,' tome i., and he there 

 states its production to be dependent on the abstraction of 

 ammonia by the atmosphere. 



From some difference which exists between this solution 

 of silver and that of the nitrate when treated by precipitants, 

 and from other circumstances, I was induced to collect and 

 analyse some of the oxide, to ascertain its identity with the 

 common oxide, or that previously dissolved. 20 grains that 

 had been dried for some hours on the sand-bath, were put 

 into a small glass retort, they were decomposed by heat, and 

 the gas liberated received over water ; it equalled 2*75 cubical 

 inches. 18 grains of silver remained in the retort, and the 

 2'75 of oxygen being equivalent to '935 grain, we have those 

 numbers as the proportions of the elements in the oxide, the 

 * Quarterly Journal of Science, iv. 268. 



