Discharge in a Transverse Magnetic Field. 53 



proportional to current strength, within the limits of the actual 

 experiment, the twist is also proportional to the intensity of 

 Fig. 12 a. Curve I. 



- 



1 





I i 1 1 



j 









\ 



mi 





I , 



/! 

 1 





I 





1 IN 



1/ 











1 II ■ 1 1 1 1 / ; 







1 j f 1 . ! ; 



/III 









1 





ii i 



/ 



. | II 











I 





1 i / 



/ 



1 

















i \/ 





i 



















/\ 





: ; 



















' 









1 

 1 















.. L i I J _ 1 





i 





i 





/ 







1 





/ 



' 





| 











i 1 



/ 



/ 











1 









! rv 













I 





























; 













/ • 

















i 





























i i 



























_1 : ' 



























50 60 

 ■> Ocflectu 



70 GO 



? in degrees. 



[Nature of the discharge. — When the induction-coil is started, nearly 

 the whole space is dark, and then a bright band with a dark space 

 near the cathode gradually appears.] 



the magnetic force. Fig. 12 6, curve II. gives the amount 



of twistfor different current strengths at a lower pressure. 



It is seen that the corresponding twists are greater in this 



case than those at a higher pressure. 



H13, An approximate theory of the magnetic action of the 



excited magnetic field on these discharges can he worked 



out as follows : — 



% Using cylindrical coordinates, z, p, (where z is measured 



from*the Faraday dark space [11], the equations of motion 



oPan ion may he written, if m is its mass, 



m -i + Az = Ze + Hep0, (1) 



m (p-pd 2 ) + A P = ~R, (2) 



m- ~ (p 2 d) + A P 6 + B6 = E.ez, . . . f3) 

 p at 



where A = coeff. of viscosity, B a coeff. to be determined, 



