64 THE NEW KNOWLEDGE. 



of the drop, it is next possible to determine, by calculation 

 and experiment, the mass of water .deposited from the 

 cloud ; and knowing these two factors, the number immedi- 

 ately follows from the equation, n=-|~ a 3 , where n is the 

 number of drops (and, hence, the number of corpuscles), 

 | the volume of water deposited in the form of drops, and a 



the radius of the drop. Having the number of corpuscles 

 in the gas, the electrical charge on each individual corpuscle 

 follows by experimentally determining the total electrifica- 

 tion and dividing by the number. 



The value of e turns out to be 0.00000000034 in electro- 

 static units. And, now, finally, we are in a position to know 

 the mass, or amount of matter, in a corpuscle. 



