56 



THE NEW KNOWLEDGE. 



signify their presence in the electrometer in connection with 

 it. 



So far, so good. But how does this help us to the weight 

 and velocity of the corpuscles ? Let us see. The first thing 

 we notice is that while the electrometer, or measurer of elec- 

 trification, connected with the plate, D, is charged on the im- 



Fig. 12. Experiment for determining the velocity of a corpuscle. 



pact of the corpuscles, the electrometer connected with C is 

 quite unaffected. This shows us that the corpuscles tend to 

 travel in straight lines. The next thing to be noticed is that 

 on the approach of a magnet the corpuscles may be deflected 

 so that they fall on (7, and its electrometer will show a cor- 

 responding deflection, Fig. 13. A photographic representa- 

 tion of a beam of corpuscles shows plainly the deflection 



