1894.] Researches on Explosives. 207 



15,000 atmospheres), but the former explosive I have not succeeded 

 in. detonating, while gun-cotton can be detonated with the utmost 

 ease. It is obvious that if we suppose a small charge fired in a 

 vessel impervious to heat, the rapidity or slowness of combustion will 

 make no difference in the developed pressure, and that pressure will 

 be the highest of which the explosive is capable, regard being of 

 course had to the density of the charge. I say a small charge, be- 

 cause, if a large charge were in question and explosion took place 

 with extreme rapidity, the nascent gases may give rise to such 

 whirlwinds of pressure, if I may use the term, that any means we 

 may have of registering the tension will show pressures very much 

 higher than would be registered were the gases, at the same temper- 

 ature, in a state of quiescence. I have had innumerable proofs of 

 this action, but it is evident that in a very small charge the nascent 

 gases will have much less energy than in the case of a large charge 

 occupying a considerable space. 



The great increase in the magnitude of the charges fired from 

 modern guns has rendered the question of erosion one of great im- 

 portance. Few, who have not had actual experience, have any idea 

 how rapidly with very large charges the surface of the bore is re- 

 moved. Great attention has therefore been paid to this point, both 

 in regard to the erosive power of different explosives and in regard 

 to the capacity of different materials (chiefly different natures of 

 steel) to resist the erosive action. 



The method I adopted for this purpose consisted in allowing large 

 charges to escape through a small vent. The amount of the metal 

 removed by the passage of the products of explosion, which amount 

 was determined by calibration, was taken as a measure of the erosive 

 power of the explosive. 



Experiments have also been made to determine the rate at which 

 the products of explosion part with their heat to the surrounding 

 envelope, the products of explosion being altogether confined. I 

 shall only briefly allude to these experiments, as. although highly 

 interesting, they have not been carried far enough to entitle me to 

 speak with confidence as to final conclusions. 



Turning now to ballistic results. The energies which the new ex- 

 plosives are capable of developing, and the high pressures at which 

 the resulting gases are discharged from the muzzle of the gun, render- 

 length of bore of increased importance. With the object of ascer- 

 taining with more precision the advantages to be gained by length, 

 the firm to which I belong has experimented with a 6-inch gun of 

 100 calibres in length. In the particular experiments to which I 

 refer, the velocity and energy generated has not only been measured 

 at the muzzle, but the velocity and the pressure producing this 

 velocity have been obtained for every point of the bore, consequently 



