RESEARCHES UPON SALICIN. 
147 
I prepared the salicylate of silver by digesting the salicylic 
acid in an excess of a solution of ammonia, driving off the excess 
by boiling, and then precipitating with a neutral solution of 
nitrate of silver; the salicylate of silver falls down as a white 
insoluble powder. It was then separated, reduced to powder 
and dried on a salt water bath. The results of its analysis 
were: 
0.420 of the salicylate gave 0.079 water and 0.530 carbonic 
acid. 
0.307 of the same yielded 0.133 metallic silver. 
These data give the following as its composition. 
Theory, 
Analysis. 
1070.16 
34.70 
34.91 
H io 
62.40 
2.02 
2.09 
s 
500.00 
16.22 
16.43 
AgO 
1451.51 
47.06 
46.57 
3084.17 
100.00 
100.00 
Alteration of Salicide of Potassium by the air, and of 
Melanic Acid. 
I have already had occasion to say, that when salicide of 
potassium, slightly moist, is exposed to the air, it is promptly 
covered with spots, at first green, but finally black. At the 
end of a few days, the whole mass becomes black. If the ex- 
periment be made over mercury, in a jar filled with oxygen, 
the metal rises in proportion as the reaction goes on, and the 
oxygen is finally absorbed. When no oxygen is present, or 
when this gas and the matter are perfectly dry, there is not any 
alteration. To facilitate the action, it is necessary to moisten 
the mass occasionally with a few drops of water. 
When the change is complete, the mass presents a carbon- 
aceous appearance. By repeated washings with water, there 
is left a powder resembling soot. This powder is insipid, in- 
soluble in water, very soluble in alcohol, ether, and the caustic 
alkalies. Acids precipitate it unchanged from its alkaline so- 
lutions. It decomposes the alkaline carbonates, liberating 
carbonic acid. Heated on platinum foil, it burns without 
