444 Count Le Maistre's Memoir on [Dec 



The following process likewise furnishes aprussiate of sulphur 

 of a very beautiful colour. 



I boiled in water one part of hydrosulphuret of potash and one 

 part of prussiate of potash. I added weak muriatic acid at a 

 boiling temperature, which immediately produced the green 

 combination. No sensible portion of sulphuretted hydrogen 

 was developed. 



VI. Prussiate of Phosphorus. 



Phosphorus has a great deal of affinity for prussic acid. To 

 produce a combination it is sufficient to boil some grains in a 

 solution of prussiate of potash, and to pour muriatic acid into 

 the liquid. It becomes muddy, and assumes a green colour. 

 The boiling is to be continued till no more melted phosphorus 

 can be seen at the bottom of the matrass. The prussiate has 

 then the colour of Scheele's green, and in process of time becomes 



blue. 



It would seem that phosphorus can unite in several propor- 

 tions with prussic acid. If we employ a weak solution of 

 prussiate of potash, the colour is less intense, and passes with 

 difficulty to blue. If we employ a concentrated solution, and 

 pure muriatic acid, the prussiate, when dried, is absolutely 

 black, and becomes luminous. The excess of phosphorus burns 

 slowly, and leaves a dark-violet coloured matter, which gradually 

 changes into a perfect blue. 



Prussiate of phosphorus, when well made, is more beautiful 

 than prussiate of iron, and is neither purple nor greenish. 



VII. Prussiate of Gold. 



A solution of ducat gold diluted with much water, treated 

 during its boiling with prussiate of potash, gave immediately a 

 copious blue precipitate, which was deposited rapidly, and had 

 a very fine colour. 



VIII. Prussiate of Silver. 



As all the nitric acid solutions have a tendency to give a green 

 phade to the prussiates derived from them, we obtain only an 

 imperfect blue with nitrate of silver; but we get a very fine blue 

 by operating on the muriate of silver newly precipitated by 

 muriatic acid. It is washed upon the filter, and boiled in water, 

 before it is coloured by light. Muriatic acid is added, and then 

 prussiate of potash. A prussiate is formed of a clear and bril- 

 liant blue, which becomes gradually more intense. This is the 

 prussiate of muriate of silver. 



IX . Prussiate of Tin. 



The dispxygenizing property of muriate of tin renders the 

 formation of blue prussiates with it difficult ; but we obtain them 

 with facility when we operate upon the oxide of tin precipitated 

 from the nitrate by an alkali, well washed, and employed while, 



