SOME CONTEMrOR.lh'V J/)//. /.V(7:.V /.V I'HYSICS^M 



473 



gauze El, and then turned back by an adxerse potential-fall Vo before 

 they reach the partition Eo pierced by the slit ^"2. Positive ions pro- 

 duced bv the electrons in the region between £1 and Eo are drawn 



...^ 



I.e. 



\ 



WWVV.WWV' 



!.^^^^^s^^^^^^^^■^■.■^^^^^^^'^'s^^'^^^■^'^ 





Fie. 3 



toward Eo; some of them emerge through S2, and encounter an addi- 

 tional potential-fall Vz which draws them to the partition E^. Those 

 which pass through the slit S3 are now ready, after passing through the 



