SILVER NITRATE ; EDWARD DIVERS. 13 



Theoretically, it is quite probable that nitric oxide does 

 not, after all, act directly upon silver nitrate. For, making 

 the allowable supposition that, to a minute extent, silver nitrate 

 decomposes into silver nitrite and oxygen at temperatures much 

 below that at which it does so sensibly, the nitric oxide may 

 be regarded as active by combining with this oxygen and thus 

 by removing it greatly hastening the spontaneous decomposition 

 of the nitrate. This decomposition, thus assisted, occurring at 

 temperatures at which silver nitrite is comparatively stable in 

 presence of nitrate, the nitrite remains, though at higher tem- 

 peratures it decomposes almost as fast as it gets formed from 

 the nitrate. According to this theory, silver nitrate is not 

 actually decomposed by nitric oxide, but only decomposes much 

 more rapidly in its presence, in consequence of its interaction 

 with one of the decomposition products. For practical purposes, 

 silver nitrate and nitric oxide may however be treated as active 

 upon each other when heated together. 



Nitric oxide has no action upon sodium, potassium, or 

 barium nitrate, even at the temperature of boiling sulphur. 



Lead nitrate soon begins to decompose by heat alone and 

 nitric oxide seems to be without effect upon its decomposition. 

 According to Stas, lead nitrate begins to decompose somewhere 

 above 200°. T find that, for its fairly free decomposition, a 

 temperature not much below 400° is required. At the boiling 

 point of sulphur, even, the decomposition proceeds at such a 

 moderate rate that only after ten minutes heating does the salt 

 show distinct signs of fusing. No nitrite is produced, but there 

 is formed a very little peroxide of lead. By washing the mass 

 with cold water and then boiling it out with water, abundance 

 of the beautiful, crystalline, white salt, Pb(OH)NO„ is obtained. 



