104 HISTORY OF ritUSSrATES. 



Progress of its When this salt enters into fusion, a little prussic acid 

 by heat. * " csca P es » which is seized by the ammonia that is formed at 

 the same time. Afterward a nebulous vapour rises, which 

 condenses in the neck of the retort in a meally powder. 

 This vapour is not reproduced when the fusion is at an 

 end. On examination the sublimate has the alkaline and 

 bitter taste of simple prussiate. 



Alcohol dissolves a portion of it, and what separate* 

 from it is triple prussiate unaltered : that is to say, this 

 gives prussian blue with solutions of red oxide, while the 

 other cannot. 



If a lighted candle be applied to the mouth of the retort, 

 the prussic acid burns alone ; and the carbonic acid, arising 

 from its combustion, forms with the ammonia crystals of 

 ammoniacal carbonate, which condense in the neck of the 

 retort a few lines beneath the flame. We will now pro- 

 ceed to examine the melted prussiate. 



The mass resembles melted muriate of soda, is of an 

 ashen gray, and strongly attracts moisture. 



If we taste a bit of it, we find nothing of the sweetness 

 «f the triple prussiate, but an alkaline taste, flavoured 

 with the bitterness of the kernels of stone fruit. This 

 flavour announces, that there is simple prussiate of potash 

 in this residuum. A few drops of acid extricate a gas, 

 which does not belong to this prussiate, and which give Or 

 suspicion, that it contains carbo«ate of potash also. 



Finally this mass, if set by to dissolve, deposits a black, 

 jnicaceous, shining powder. On collecting it in a filter, it 

 is found to be a mixture of charcoal, pure iron, and a 

 little sulphuret of iron. The last is an accidental product. 

 Its sulphur proceeds from the decomposition of me sulphate 

 pf potash, from which it is not easy to free the triple 

 prussiate. This powder is obedient to the magnet. A 

 weak acid disengages first sulphuretted hidrogen, then 

 aromatic hidrogen, and at length nothing remains \mt 

 charcoal powder. 



Examination of the Solution of the Residuum. 

 The residuum If alcohol at 25° be mixed with it, immediately p shining 

 pearly snow is formed, which may be collected on a filter. 



Dissolved 



