DYNAMITE WITH AMMONIUM NITRATE BASE. 439 



will therefore be diminished proportionately to the weight of 

 the inert matter in the mixture ; while the maximum work will 

 retain the same value, being always proportional to the weight 

 of nitroglycerin. 



The same circumstances will render the propagation of simple 

 ignition of a small portion of the mass into the neighbouring 

 parts more difficult, since the latter explode only when raised 

 suddenly to a temperature approaching 200. Hence the ex- 

 plosion produced by a detonator requires a greater initial 

 disturbance in order to take place. 



If deflagration be produced by the shock of a hard body, or 

 of a fulminating fuse, the solid particles interspersed in the 

 liquid divide the energy of the shock between the inert and 

 the explosive substance, in a proportion depending on the 

 structure of the inert substance. The latter thus changes the 

 law of explosion ; it opposes itself to some extent to the propa- 

 gation of the explosive wave, except in the case of extremely 

 violent shocks, and introduces an extreme diversity into the 

 phenomena, as follows from the experiments of Nobel, and those 

 of Grirard, Millot, and Vogt, on nitroglycerin mixed with silica, 

 alumina, ethal, or sugar. 



It is, moreover, evident that the useful effects of the inert 

 substance could only be completely produced when the mixture 

 is homogeneous, and without any separation of liquid and nitro- 

 glycerin, for the liquid which has exuded retains all its pro- 

 perties, hence the necessity of the special structure in a solid 

 substance. 



3. DYNAMITE WITH AMMONIUM NITRATE BASE. 



1. This substance is very interesting on account of the great 

 energy which is derived both from nitroglycerin and ammonium 

 nitrate, whether associated or not with a complementary com- . 

 bustible substance. 



It has been proposed on various occasions by inventors, with 

 certain variations due to the introduction of the complementary 

 bodies (charcoal, cellulose, etc.), the latter being for the double 

 purpose of utilising the excess of oxygen supplied both by nitro- 

 glycerin and ammonium nitrate, and for completing the absorbent 

 properties of the substance. 



But this dynamite presents a certain drawback, because 

 ammonium nitrate is hygroscopic, especially in an atmosphere 

 saturated with moisture. Moreover, water immediately separates 

 nitroglycerin from it. 



2. The relative proportions of nitroglycerin, ammonium nitrate, 

 and combustible substances may vary extremely, even when it 

 is subjected to the condition of a total combustion. We shall 

 consider only the mixtures in which charcoal constitutes the 



