104 



Nitro- Glycerine. 



of Professor Abel above quoted. 4 Only a distinct spark 

 will fire this composition, and induced atmospheric electri- 

 city is incapable of causing a premature explosion in the 

 fuses charged with it. 



Eleven lives have been sacrificed by the use of the cot- 

 ton-covered wire and sensitive fulminate copper compound, 

 and the consumers of these articles are becoming alive to the 

 necessity of using an insulation to their conducting and 

 exploding wires capable of retaining the intense electri- 

 city which, leaping between two points, is shown as a spark. 



To convey an idea of the explosive force of nitro-glycerine, 

 I will just state the average quantity per cubic yard used at 

 Erie harbor for the Philadelphia and Erie R. R. Co., 

 who found it much cheaper to remove the rock so as to 

 form a channel for ships to lay at their wharves, than to 

 form cribs and dump in filling, to reach out to the depth 

 of water required, viz : fourteen feet. The engineer in charge 

 reports one ounce and six-tenths of an ounce for each cubic 

 yard of rock blasted out, in such condition as to dredge 

 like gravel. But there are qualities of nitro-glycerine very 

 different from this, for at Coenties reef the government 

 officers have been using sixty ounces per cubic yard, or 

 nearly forty times the above quantity used at Erie harbor. 



The fact is, nitro-glycerine emulsion, that is, an impure 

 or imperfectly converted nitro-glycerine, which contains 10 

 per cent of water surrounding each atom of nitro-glycerine 

 and interfering with its instantaneous blasting force, is 

 little if any better than gunpowder, and only a transparent 

 homogeneous compound will be found to give the best at- 

 tainable results. Few conceive the amazing difference of 

 explosives, nominally the same, really differing but little, 

 but when the facts are remembered, that colorless trans- 

 parent tri-nitro-glycerine is increased in volume 13,400 

 times, water 1,750 times and powder 2,000 times in con- 

 version into vapor ; that nitro-glycerine is converted with 



