SYNTHETIC CHEMISTRY 



further, and show that an explosion always pro- 

 ceeds in the form of a wave. It is instantaneous 

 to us only because our sense-perceptions are limit- 

 ed in such a way that a series of impressions, fol- 

 lowing very quickly, as in the kinematograph, seem 

 continuous. 



These researches reduced the vague and rather 

 incoherent notions of explosives, which were regnant 

 when M. Berthelot took up the study, to clear and 

 precise deductions, which enabled the chemist to 

 foresee and foretell the effects of any given reaction. 

 They explained why many explosions are incom- 

 plete; in the old days often only a part of the 

 powder was burned, the rest was blown away in- 

 tact; this was the origin of the so-called "powder 

 wounds." The new methods provided a means 

 to control the time of the explosion, so that it is 

 easy enough now to make a powder which will burn 

 like an ordinary match. They made it possible 

 to augment enormously the shattering force of 

 explosive compounds. 



When M. Berthelot began, the old black powder, 

 improved slowly since the sixteenth century, was 

 still in universal use. Gun-cotton, it is true, had 

 been discovered as far back as 1838, but the ra- 

 pidity of its action and the danger from its use were 

 a bar to its general employment. A long series of 

 researches, rivalling in fertility and number those 



