Theory of Explosions. 177 



ened or otherwise, the results obtained might be anticipated 

 on almost any theory except that of " synchronous vibration/' 

 For the vibrations supposed on this theory to be most active, 

 would be precisely those absorbable by lampblack. This 

 point has been investigated by Berthelot, in volume i. of the 

 Treatise, in a manner which leaves little doubt that he mis- 

 understood Abel's theory. In order to show the importance 

 of vibrations in producing chemical change, Berthelot experi- 

 mented on various chemicals by swinging them on tuning- 

 forks. No effect was produced, nor indeed was it to be 

 expected, unless the reagents were of such a nature that they 

 required intense shaking to keep them mixed. Berthelot also 

 experimented on ozone at much higher frequencies of vibra- 

 tion by causing a tube filled with the gas, mixed with oxygen, 

 to be set into violent longitudinal vibration. No change in 

 the ordinary rate of decomposition of ozone was observed. 

 This is very interesting, but does not, as far as I can see, 

 touch Abel's theory. In order to disprove the theory, Ber- 

 thelot ought to have made his tube vibrate till it got luminous, 

 and observed the effect on the ozone all the way up. 



There are many well-established cases of torpedoes ex- 

 ploding one another by influence, and the same thing occurs 

 in firing dynamite shots in mines. The former alone possess 

 any interest for our present purpose. If the effects due to 

 fulminate of mercury when fired under water are in any way 

 similar to those which may be supposed to take place on the 

 detonation of large charges of gun-cotton, then, by the expe- 

 riments described above, it would be likely that quite extra- 

 ordinary effects might be propagated in some cases. There 

 ought, however, to be a capriciousness in the observed action 

 of torpedoes on one another ; but whether this has been 

 observed or not, I am unfortunately unable to state. How- 

 ever, I will assume that it has not, and that here we have a 

 case where the effect is largely due to " synchronous vibra- 

 tion." We will therefore consider the ways in which 

 vibrations of sufficiently small period could be transmitted. I 

 assume that no vibrations can have any influence unless they 

 are of such a period as to be comparable with the natural 

 period of vibration of the molecules of the substance to be 

 xploded. 



Let a body be gradually heated and its temperature mea- 

 sured as soon as light comes from it having the same refran- 

 gibility as the line A in the solar spectrum. Let the 

 temperature be, say, of the order of 1500° Centigrade. Then 

 the molecules of the body will be vibrating in some way 

 comparable with the period of the A line ; that is, about 

 4x 10 14 times per second. 



