NITRO-GLYCERINE. J 6] 



force of nitro-glycerine is much greater than that of any of the 

 others. The following is his table : 



Sporting powder 



Military " 



Blasting " 



Powder with excess of C 



" " sodium nitrate 



" " potassium chlorate. . 



Chloride of nitrogen 



Nitro-glycerine 



Gun (Jotton 



" " with nitre ......... 



" K CI O3 



Potassium picrate 



Picrate with nitre 



" KCIO, 



Quantity of heat 

 evolved by one 

 kilo, in units. 



644000 

 622500 

 380000 

 429000 

 769000 

 972000 

 B 16000 



1282000 

 700000 



1018000 



1446000 

 872000 

 957000 



1405000 



Volume of 



Gas found in 



M. C. 



0.216 

 225 

 355 

 0.516 

 0.252 

 0.318 

 0.S70 

 0.71O 

 0.801 

 0.484 

 0.484 

 0.585 

 0.337 

 0.337 



Product of 



tliese two 

 Numbers. 



139000 

 140000 

 135000 

 219000 

 194000 

 3U9000 

 117000 

 910000 

 560000 

 492000 

 700000 

 510000 

 323000 

 474000 



Fi-om this table it appears that the explosive force of nitro-glycer- 

 ine is 910,000, while that of blasting powder is 135,000, and that of 

 gun cotton 560,000. Hence we may say that nitro-glycerine ex, 

 plodes with rather more than six times the force of ordinary blasting 

 powder, and not quite twice the force of an equal weight of gun 

 cotton. This great explosive force suggested its value as an agent 

 for blasting rocks, &c., but great practical difficulties stood in the 

 way of its adoption. In addition to the great danger attendant on 

 its manufacture and transport, the fact that it would neither explode 

 by contact with flame nor by the electric spark, for a long time pre- 

 vented its employment in the arts. At last, in 1864, these difficul- 

 ties were overcome by Mr. A. Nobel. In his first experiments he 

 used gunpowder soaked in nitro-glycerine, but his discovery before 

 alluded to, that nitro-glycerine may be exploded by the detonation of a 

 small quantity of some other explosive, such as fulminate of mercury, 

 was the means of converting this powerful explosive into an industrial 

 agent of the highest value. It came to be extensively used on the 

 continent of Europe in mining and other blasting operations, and it 

 has also been largely and successfully used in the United States. 



As examples of its employment, the boring of the Hoosac Tunnel 

 and the removal of the obstructions at Hell Gate may be mentioned. 

 At one blast in the Hoosac Tunnel the rock was blown out in the 

 centre to a depth of eight feet ten inches. For blasting purposes the 



