SYNCHRONOUS VIBRATIONS AND THE EXPLOSIVE WAVE. 533 



the sudden shock produced by the explosion of mercury 

 fulminate. 



13. Hence we are led to account for explosions by influence, 

 peculiar phenomena which have singularly attracted the atten- 

 tion of artillerists and engineers. 



. It has been seen, for instance, that a cartridge of dynamite or 

 gun-cotton, exploded by means of a fulminate priming, causes 

 the explosion of the neighbouring cartridges even when placed 

 at considerable distances, and without the detonation being 

 followed by a direct propagation of the inflammation. Torpedoes 

 charged with gun-cotton and submerged will also explode 

 under the influence of strong cartridges of the same agent 

 placed in the vicinity. In the present work it has been shown 

 how these phenomena explain themselves by the development 

 of the explosive wave in the detonating substance, and by the 

 violence of the sudden shock which results therefrom, and 

 which the surrounding medium transmits to the second 

 cartridge. 



Here is recalled to mind, though the author does not adopt 

 it, the ingenious theory of synchronous vibrations, according to 

 which the determining cause of the detonation of an explosive 

 body consists in the synchronism between the vibrations of the 

 body which causes the detonation and that which would be 

 produced by the body acted upon. It is shown that this theory 

 does not in reality explain the facts observed, and the chemical 

 stability of matter in sonorous vibration is proved by direct 

 experiment ; these experiments have been made with the most 

 unstable substances, such as ozone, arseniuretted hydrogen, 

 persulphuric acid, oxygenated water, etc. 



The sonorous waves, properly so called, are not therefore the 

 real agents propagating chemical decompositions and explosions 

 by influence ; their energy and their pressure are too slight to 

 provoke such effects. But propagation takes place in conse- 

 quence of the explosive wave, a phenomenon of quite a different 

 nature, and in which the pressure and energy are incomparably 

 greater, and are incessantly regenerated throughout the wave by 

 chemical transformation itself. 



Thus, according to the new theory, explosive matter detonates 

 by influence, not because it transmits the initial vibratory 

 movement by vibrating in unison, but, on the contrary, because 

 it stops it and appropriates to itself the energy thereof. 



14. Let us examine somewhat more closely the characteristics 

 of this explosive wave which we have been led to discover, and 

 of which we avail ourselves, in order to explain the detonations of 

 dynamite and gun-cotton. Its discovery, as well as the study 

 of it, constitute one of the most interesting chapters in the 

 present work. 



It is in gaseous media that the study of it is at one and the 



