240 



Sir David Salomons, Bart. 



[June 21, 



number of bands in the tube will not advance nor recede, nor alter 

 their number in any way ; neither can they be made to disappear by 

 increasing the current as in other cases. The only thing that happens 

 is that the bright bands grow wider as the current is increased till 

 the paradox referred to is apparent. 



This same experiment is made on a number of tubes built in a 

 similar fashion, but having different dimensions. The result, how- 

 ever, is always the same. The overlapping of the bright bands may 

 occur again and again, so that the dark spaces are first bright, then 

 dark, then again bright, and so on, until the tube is destroyed by the 

 excess of current passed. 



Experiment 5. 



I find that if a tube is employed similar to that in the last case, 

 but with a glass disk placed at the end of it (see fig. 5), the same 



Fia. 5. 



