492 Intelligeiice and Miscellcmeous Articles, 



PURPUllATE OF SILVER. 

 This salt, first obtained by Prout, was dried at 26G° Fahr. It was 

 analysed by the usual methods, and gave by 



Experiment. Calculation. 



Hydrogen 1-31 1-32 or H'o 



Carbon 25-75 25-89 Cis 



Oxygen 23-19 23-30 0'> 



Azote 19-02 18-75 N>o 



Oxide of silver . . 30-73 30-74 Ag 



100- 100- 



The basic purpurate of silver is obtained by adding ammonia to 

 nitrate of silver until the precipitate is redissolved, and with this solu- 

 tion purpurate of ammonia is to be precipitated. The author could 

 not effect the analysis of this salt, for having exposed it to a tem- 

 perature of 392° Fahr. in an oil-bath, the whole mass was decom- 

 posed. 



PURPURATE OF POTASH. 



This salt was obtained by Prout, who recommends it to be jire- 

 pared by decomposing a boiling solution of purpurate of ammonia 

 by means of a solution of bicarbonate of potash ; but as it is in 

 this method impossible to avoid a disengagement of ammonia, which 

 when heated acts upon the purpurate, it is better to employ nitrate 

 of potash. The purpurate of potash is difficultly soluble in water, 

 but not insoluble ; it is much less soluble in saline solutions : on 

 this account it is proper to employ great excess of nitre in prepar- 

 ing it. This purpurate is pulverulent, and consists of very small 

 reddish brown microscopic crystals ; it may also be obtained in large 

 crystals, which have the colour and lustre of the ammoniacal com- 

 jiound, or perhaps rather deeper. The analysis of this salt, care- 

 fully performed, gave 



By Experiment. Calculation. 



Hydrogen 1-33 1-33 or H^ 



Carbon 31-23 32-63 C>« 



Azote 24-05 23-62 N'" 



Potash 15-48 15-73 K 



26-69 O'o 



100- 

 The indigo blue liquid which is obtained when purpurate of am- 

 monia is dissolved in a solution of caustic potash, is probably de- 

 rived from the formation of a basic salt, which cannot be procured 

 in a solid form. 



PURPURATE OF AMMONIA. 

 The properties of this salt are perfectly well known by the experi- 

 ments of MM. Liebig and Wohler, but still neither the composition 

 nor the formula which they have given is correct. In order to pro- 

 cure this salt, which is prepared with difficulty by the usual methods, 

 M. Fritzche employed a process which yields it readily and in great 

 abundance. This process is derived from the observation he had 



