DYNAMITE PROPER. 435 



we meet another stumbling-block ; the substance requires special 

 capsules and too great a quantity of fulminate to explode it. 

 This must be compensated for by employing a small inter- 

 mediate cartridge of compressed gun-cotton, primed itself with 

 fulminate, which complicates the question. It appears that 

 even in this way it is sometimes difficult to effect the explosion 

 of blasting gelatin. 



16. This technical discussion will not be further entered 

 upon here except to observe that the absence of explosion by 

 simple ignition, and the necessity for special detonators, are 

 among the number of essential characteristics which distinguish 

 dynamite from service powder and all analogous kinds. 



Hence arise fresh complications in the use of these substances. 

 Thus, owing to this circumstance and the risk of explosions by 

 influence, the detonators should be carefully kept apart from 

 the stores of dynamite, in magazines, and during transport. 

 Many accidents are due to the neglect of this precaution. 



17. These general notions being set forth it would require 

 a whole volume to enter into the study and the discussion of 

 the properties of all the dynamites proposed, or even only of 

 those actually employed. This is why we shall confine our- 

 selves to treating with more detail three interesting varieties of 

 dynamite in order to show how our theories are applied to their 

 study. They are 



1st. Dynamite proper with silica as base. 



2nd. Dynamite with ammonium nitrate as base. 



3rd. Blasting gelatin with collodion cotton as base. 



2. DYNAMITE PEOPER* 



1. We have said above how Nobel had invented this substance 

 to obviate the terrible effects which result from the propagation 

 of shocks in liquid nitroglycerin. Now, dynamite proper, being 

 less sensitive to shocks than nitroglycerin, can be transported 

 and handled almost without danger, provided certain rules be 

 observed. 



2. For many years dynamite has been employed in mines 

 and in tunnel boring to rupture and reduce very hard or 

 fissured rocks, as well as in harbour and other works. It has 

 been applied to break up blocks of stone, masses of cast or 

 wrought iron, blocks of pyrites, beds of flint, accumulated ice, 

 to break up and lighten soils intended for vine growing, etc., 

 and its applications are daily being developed. 



Dynamite also plays a most important part in warfare 

 (torpedoes, mines, the destruction of palisades, the levelling of 

 trees, buildings and bridges, the destruction of rails and rail- 

 ways, the bursting of cannons, etc.). 



2F2 



