352 Materials for a History of the Prussiates. 



k is triple prussiate without alteration , i. e. the latter give^ 

 Prussian blue with the solutions of red oxide, while the other 

 cannot give any. 



If we present a lighted candle to the beak of the retort, 

 the prussic acid burns alone, and the carbonic acid pro- 

 ceed; u_ r from its combustion forms with ammonia crystals 

 of carbonate, which are condensed in the neck of the retort 

 a few lines above the flame. Let us now pass to the examina- 

 tion of the fused prussiate. 



The mass resembles fused sea-salt : it is of an ash-gray, 

 and strongly attracts humidity. 



If we taste a piece of it, we do not discover the sweet- 

 ness of the triple prussiate, but an alkaline taste perfumed 

 with the bitterness of almond kernel supplies the place. This 

 taste announces already, that there is simple prussiate of 

 potash rri this residue. Some drops of acid liberate a gas 

 which does not belong to this prussiate, and which suggests 

 the idea that there is carbonate of potash there also. 



Lastly, this mass when dissolved, deposits a black pow- 

 der like mica, and very brilliant. When collected by the 

 filter it is a mixture of charcoal, pure iron, and a little sul~ 

 pliuret of iron. This last is an accidental product i its sul- 

 phur proceeds from the decomposition of the sulphate of 

 potash, from which it is difficult to purge the triple prus- 

 siate. This powder is attracted by the magnet. A weak 

 acid at first disengages from it sulphureted hydrogen ; after- 

 wards comes aromatic hydrogen, and in the last place we 

 on!v find charcoal powder. 



Examination of the Solution of the Rudue. — Mix with it 

 a moderate quantity of alcohol at 25 d .rees ; there is im- 

 mediately formed a brilliant kind of snow which may be 

 collected by the filter. When dissolved and crystallized, it 

 gttoeS yellowish sweetish crystals, which, with muriatic acid, 

 furnish prussic acid and white prussiate. Here we have 

 the prussiate purged from oxide, proposed by M. Richter. 



The alcoholic solution is distilled almost dry, it is after- 

 wards covered with alcohol at 30 degrees : one portion of it 

 is then dissolved, and the rest falls to the bottom. The 

 latter when examined is carbonate of potash with some re- 

 mains 



