1818.] Oxide of Silver in Amm onia. 17 



occurred with the same solution a fourth and fifth time. The 

 liberation of the azote, therefore, does not belong exclusively 

 to the formation of fulminating silver, but seems rather to 

 depend on the production of protoxide. 



I endeavoured to form fulminating silver by using the prot- 

 oxide described in the first part of this paper, but could not 

 succeed : I got nothing but a black powder from it, which ap- 

 peared to be the same oxide in another form. I endeavoured 

 also to form fulminating silver from those portions of oxide 

 given off by the further boiling of solutions which had pre- 

 viously yielded the detonating compound, but failed ; I presume 

 from its being also a protoxide. When the fulminating com- 

 pound is dissolved in the acids, it gives off a gas which I 

 believe to be oxygen, but I could not work with quantities 

 sufficient to ascertain this point. Perhaps to these reasons 

 for supposing fulminating silver to be a compound rather 

 of the peroxide than the protoxide, may be added the easy 

 solubility of the protoxide in ammonia, and the difficult solu- 

 bility of the detonating compound. 



The oxide which is obtained by boiling solution of silver 

 in ammonia, I have supposed to be a protoxide similar to the 

 one obtained by spontaneous evaporation. This opinion is 

 founded on the liberation of azote during its formation in con- 

 sequence of the decomposition of ammonia by oxygen, and on 

 its apparent incapability of forming fulminating compounds : 

 the idea is supported by the following circumstance. A tube, 

 in which solutions of silver in ammonia had been repeatedly 

 boiled, became coated on the inside with the oxide, so as to 

 be perfectly opake; on pouring dilute nitric acid into it to re- 

 move the oxide, the tube became lined with brilliant metallic 

 silver, which, however, was soon dissolved by the continued 

 action of the acid. I attribute this phenomenon to the reduc- 

 tion of one part of the oxide by another, which was thus ren- 

 dered soluble in the acid. 



When a portion of the ammoniacal solution is evaporated to 

 dryness in a platinum capsule, it leaves a film of oxide, which, 

 when decomposed by heat, gives a perfectly continuous and 

 smooth coat of silver to the vessel. I have also covered other 

 metals, as iron and copper, with silver in the same way, and 

 found that the burnisher might be applied without any injury 



c 



