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1818.] 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 hydrogen 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 ascertained.

ease with which the compounds of silver are dissolved by ammonia, and the frequent formation of powerfully detonating and dangerous substances in these solutions, are well known. I have been induced to examine some of the phenomena 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&middot;75 cubical inches. 18 grains of silver remained in the retort, and the 2&middot;75 of oxygen being equivalent to &middot;935 grain, we have those numbers as the proportions of the elements in the oxide, the