TROWBRIDGE. — ELECTRIC DISCHARGES. 641 



ance of such revolving streamers which fairly represent what may be 

 seen at the terminal of a discharge tube in a magnetic field, and call 

 to mind the coronal streamers. The magnetic phenomenon described in 

 8 may also have a bearing upon the coronal streamers at the poles of 

 the sun. When the lines of magnetic force are at right angles or trans- 

 verse to the direction of the electric discharge, at comparatively high 

 pressures, one to two centimeters with currents from 5 to 20 centimeters, 

 3,000 to 8,000 volts in wide tubes, streamers radiate from the position 

 of the magnetic pole. It will be noted that these striae make their 

 appearance at a much higher pressure than that of the usual striae in 

 rarefied gases. 



Thus electric discharges around or toward the poles of the sun trans- 

 verse to the lines of magnetic poles of the sun could be separated into 

 streamers. What conclusions can we draw from such varied phenom- 

 ena ? A short consideration of the elementary mathematical treatment 

 given by J. J. Thomson in his treatise on " Discharge of Electricity 

 through Gases " will help us, I think, to analyze the phenomena. Pro- 

 fessor Thomson discusses the case of one ion moving through a gas, the 

 viscosity of the gas causing the velocity of the ion to be proportional to 

 the force acting upon it. Since there is a mechanical force acting upon 

 the ion perpendicular both to the electric force and the direction of the 

 magnetic force, we have 



yl^ components of ^ f components of f components of 

 2 \ electric force, I magnetic force, w \ magnetic force. 



Components of mechanical force X e , T € , Z e , c being the charge on the 



ion, R the velocity of the ion under unit electric intensity. We then 



have , o \ 



e(pu> — yv), 



€ (y u — a w), 

 c (av — fiu). 

 U= R(X + fiw — yv), 

 V = R (Y -\- yU — a w), 

 W = R(Z + av — fill). 

 _ RX+R i (yY-fiZ)+R i a(aX+fiY+yZ) 

 1 + R 2 (a 2 + fi 2 + y 2 ) ~' 



V = RY + K 2 (aZ-yX) + R*fi(aX+ fiY+yZ) 



1 + R* (a 2 + /J 3 + /) 

 tc ._ RZ + W(PX+ a Y) + R S y(aX+ fiT+yZ) 



1 + R- (a 2 + fi 2 + y 2 ) 



VOL. XLI. — 41 



