Mr. R. Phillips on the Triple Pnissiate of Potash, 111 



It will be observed that the carbon and azote are equiva- 

 lent to three atoms of cyanogen ; and Berzelius considers the 

 salt as a double cyanide of iron and potassium, containing 

 water of crystallization, or as 



1 atom cyanide of iron .... 26 -f 28 = 54> 



2 atoms cyanide of potassium 52 + 80 = 132 

 3 water i■M,^\■JH%:. ... 27 



"2T3 



As the atomic weights of the salt given by these analyses 

 differ so greatly, and the quantities of the elements consti- 

 tuting it do not in any instance agree, it was evidently requi- 

 site to repeat the analysis, to a certain extent at least, be- 

 fore any probable theoretical views of its nature could be de- 

 veloped : I therefore made the following experiments. Two 

 hundred grains of the crystallized triple prussiate were dis- 

 solved in a mixture of dilute nitric and muriatic acids ; the so- 

 lution was evaporated to dryness, so as to dissipate the car- 

 bon and azote, and convert the iron into peroxide. The re- 

 siduum being dissolved in muriatic acid, and the solution de- 

 composed by ammonia, gave 38*8 grains of peroxide of iron, 

 equivalent to 27*16 of iron or 13'58 per cent. 



The solution from which the peroxide of iron had been pre- 

 cipitated, consisting, of course, of muriate of potash and mur 

 riate of ammonia, was evaporated to dryness, and the residuum 

 was heated to redness in a platinum crucible, by which the am- 

 moniacal salt was expelled; and there was left chloride of po- 

 tassium weighing 139*7 grains, equivalent to 73 5 of potassium 

 or 36*75 per cent. 



A portion of the triple prussiate reduced to powder was 

 dried in a moderately-hot sand-bath till it ceased to diminish 

 in weight; it lost 12'5 per cent of water. 

 ' Assuming, according to the analysis of Berzelius, that the 

 salt is composed of cyanogen and the substances the quanti- 

 ties of which are above stated, it will appear to consist of 



Cyanogen 37*17 



Iron 13-58 



Potassium 36*75 



Water 12-50 



100* 

 These results, it will be seen, agree very nearly with those of 

 Berzelius ; — the greatest difference exists between the quan- 

 tities of potassium, amounting to about 0-8 per cent ; while 

 the proportion of iron, which of all the results I obtained 

 comes nearest to any one stated by Mr. Porrett, is more than 

 he has given it bv 1*8 per cent. 



The 



