NEW CONCEPTIONS IN SCIENCE 



bination of the platinum with the hydrogen gas, 

 then immediately a reaction between this new 

 compound and the oxygen. The first of these 

 combinations had escaped notice, for it is destroyed 

 at the moment it takes place. Other cases of this 

 mysterious force of "catalysis" were explained in 

 the same way. But new and simple mechanical 

 conceptions have to fight their way in the courts of 

 chemistry as elsewhere, and it is curious to note 

 that in many an English text-book the mysteries 

 still find a handsome place. 



These are rather special problems. The re- 

 searches of M. Bertheloton the relations of heat and 

 chemical change found quickly a very practical 

 application, for they led him inevitably to the 

 theory of explosives. The sole distinction between 

 the action of dynamite and that, say, of a candle 

 or a grate -fire is just the same distinction as be- 

 tween a flame and rusting iron. It is simply the 

 speed of the reaction. All these cases are com- 

 bustions. The oxygen of the air combines with the 

 iron slowly; it is an affair of days, or even weeks. 

 The union of coal and oxygen in the hearth or 

 stove is quicker an affair of minutes. In the case 

 of powder or nitroglycerine it is a matter of the 

 fraction of a second. With a courage that few 

 chemists possess, M. Berthelot undertook to meas- 

 ure the rate of all explosions. He was able to go 



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