470 DIAZO COMPOUNDS AND OTHERS. 



28,750 kgm. according to the theoretical formula, or 27,470 kgm. 

 according to the indications of the crusher values higher than 

 those of all known explosives. In fact, nitroglycerin gave only 

 12,376 kgm., and gun-cotton 9825 kgm. 



It is the immensity of this pressure, combined with its sudden 

 development, which explains the part played by mercury 

 fulminate as priming. 



Silver fulminate presents very similar properties ; but it is 

 much more sensitive, and therefore more dangerous. 



3. MERCURY FULMINATE MIXED WITH NITRATE. 



1. Suppose, now, mercury fulminate mixed with potassium 

 nitrate, the mixture corresponds to the formula 



that is to say, 284 grms. of fulminate to 84*2 of saltpetre ; in 

 all, 368*2 grms. Or for 1 kgm. of the mixture, 229 grms. of 

 saltpetre and 771 grms. of fulminate. 



In practice a third of saltpetre, that is, an excess, is em- 

 ployed. Antimony and lead sulphides are also added. 



2. The heat liberated is -f- 224 Gal, the mercury liquid ; 

 4- 209'6 Cal., the mercury gaseous ; or, for 1 kgm., + 609 Gal. 

 or + 567 Cal. 



3. The reduced volume of the gases = 64'9 litres, or (gaseous 

 mercury) 87*2 litres for 1 equiv. ; or, for 1 kgm., 176 litres or 

 257 litres. 



4. The permanent pressure = - - -i, with the usual re- 



servation. 



, ., a , 4380 atm. 



5. The theoretical pressure = -- TTTTT* 



n O'lJ 



It will be seen that it is less by about a third than the 

 pressure corresponding to pure fulminate. Further, the presence 

 of the nitrate diminishes the rapidity of inflammation and the 

 violence of the shock. On the other hand, it gives more 

 expansion to the flame. 



4. MERCURY FULMINATE MIXED WITH CHLORATE. 



1. The reaction is the following (exact combustion) 

 3C 2 N 2 2 Hg + 2KC10 3 = 6C0 2 + 3N 2 + 3Hg + 2KC1; 



that is to say, 284 grms. of fulminate to 81'7 of chlorate ; in all, 

 356*7 grms. ; or, for 1 kgm. of the mixture, 223 grms. of chlorate 

 and 777 grms. of fulminate. 



2. The heat liberated is + 258'2 Cal. for 1 equivalent, or 



