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CHAPTEK X. 



HEAT OF FORMATION OF MERCURIC FULMINATE. 



1. WE know the part played by mercuric fulminate in the 

 manufacture of priming. This compound probably belongs to 

 the class of diazo-compounds. M. Vieille and the author have 

 studied its heat of decomposition, from which may be determined 

 the heat of formation. 



2. The fulminate used in our experiments was taken from the 

 regulation detonators used by the Government. These deto- 

 nators contain 1/5 grm. of fulminate, and are manufactured at 

 Arras. 



3. Its analysis gave 



Calculated. 



C ... 8-35 C ... 8-45 



... 11-05 ... 11-30 



N ... 9-60 N ... 9-85 



Hg ... 71-30 Hg ... 70-40 



100-34 100-0 



The mercury was weighed as sulphide, the substance having 

 previously been oxidised by means of hydrochloric acid and 

 potassium chlorate. It is slightly in excess. This fact arises 

 from the presence of a small quantity of metallic mercury 

 mechanically mixed with the substance. 



The nitrogen and hydrogen were determined volumetrically 

 after detonation of the substance. The hydrogen may be dis- 

 regarded, its presence being due to some accidental circumstance. 

 The carbon and oxygen were determined together, as carbon 

 monoxide after detonation, by which only slight traces of 

 carbonic acid are produced. In fact, five experiments gave for 

 one gramme of the substance, 234'2 cc., containing, per 100 

 volumes 



C0 2 ... 0-15 



CO ... 65-70 

 N ... 32-26 

 H 1-80 



Theory requires 235 '6 cc. 



