442 DYNAMITES. 



which is doubtless attributable to the cohesion of matter ; that 

 is to say, to the greater mass of particles in which the energy 

 of the shock transformed into heat causes the first explosion 

 which is the origin of the explosive wave (p. 54). 



Owing to these circumstances blasting gelatin is far less 

 sensitive to explosions by influence. All these conditions are 

 very favourable to its use as an explosive for military purposes. 



3. The properties of this substance will now be more par- 

 ticularly considered. Blasting gelatin does not absorb water ; 

 it merely turns white on the surface under this influence, owing 

 to the solution of the nitroglycerin contained in the superficial 

 stratum, but the action does not go any further. The collodion 

 couon, separated by the action of the water on the first stratum 

 of substance, being insoluble in this agent, envelops the whole 

 of the rest of the mass in a protecting film. Blasting gelatin 

 therefore remains unaltered, even after having been kept for 

 forty-eight hours under running water. The explosive force 

 has been found to be the same after this test. 



Neither does freezing change its shattering force, but it causes 

 it partly to lose its insensibility to shock. 



4. The density of blasting gelatin is 1*6, i.e. equal to that of 

 nitroglycerin, as might have been expected, from its com- 

 position and its homogeneous structure without pores. This 

 density is higher than the apparent density of dry gun-cotton 

 (TO) or damp gun-cotton (1*16), which constitutes a real and 

 important advantage. 



5. Blasting gelatin burns in the open air without exploding, 

 at least when small quantities are operated upon and a previous 

 heating is avoided. It has been kept for eight days at 70 

 without being decomposed. 



After having been kept for two months between 40 and 45 

 it lost the half of the camphor and a small quantity of nitro- 

 glycerin without further alteration. 



Slowly heated it explodes towards 204. 



If it contains 10 per cent, of camphor, it no longer explodes, 

 but it fuses. 



6. Let us now estimate the strength of blasting gelatin by 

 our ordinary calculations. 



As an example, a blasting gelatin formed of 91*6 parts of 

 nitroglycerin and 8 '4 parts of collodion cotton, which are the 

 proportions corresponding to a total combustion. 



The collodion cotton is here taken as corresponding to the 

 formula 



Such a dynamite is formed in the proportions 



51C 3 H 2 (N0 3 H) 3 + 

 Its equivalent weight is 12,360 grms. 



