60 Prof. D. N. Mallik and Mr. A. B. Das on Electric 



The straight part A, B o£ curve VII. corresponds to the 

 rotatory stage of which fig. 1 is the type. The bent part 

 B, C of curve VII. corresponds to the range of pressure over 

 which the discharge undergoes only a twist [10] under the 

 magnetic force. 









Fig. 21. 



Curve VII. 















1 

 j 















tf 





so 





















/ 































50 



















































5 40 



























































V 



















! 



20 







A 























7 





















1 / 



/ 

























/ 

























f 













































< 



) 







* p. 



2 



0.- i 



■p^rk 



3 



len h 



■rth i 



n m. 



m. 





6 



It will be seen that in curves V., VI., the straight portion 

 corresponding to A, B in curve VII., is absent. 



24. We conclude, therefore, that only when there is "band" 

 discharge (which alone rotates under the influence of radial 

 magnetic field), is the ratio of potential difference to pressure 

 constant. This is in accordance with art. 5. 



It is further worthy of note that the potential difference 

 goes on decreasing as pressure decreases up to a certain 

 point ; but after that, it increases with decreasing pressure, 

 so that at very low pressures the potential difference is 

 comparable to what it is at very high pressures. 



It follows also from these experiments that the potential 

 difference at any given pressure, although it depends on the 



