500 Prof. D. N. Mallik : Theory of Electric 



kinetic energy which they retain and is, for either body, inversely 

 proportional to its mean distance from their common centre of 

 mass." I think unquestionably that a system of n bodies 

 coming together under the influence of the molecular force 

 would behave in so far similarly that they ivould retain an 

 amount of energy proportional to that given out. This amount 

 of retained energy is not to be confused with the kinetic 

 energy of a perfect gaseous condition. The paper cited 

 must be consulted in full. I think it will then be clearly 

 understood, that although the statement of Prof. Tyrer is 

 true, yet in all probability the facts that he mentions are not 

 contradictory of an inverse square law of attraction but are 

 in fact a consequence of that law. 



University of South Carolina, 

 Columbia, S.C., U.S.A. 



April 25th, 1912. 



XLVI. Theory of Electric Discharge in a De La Rive's Tube. 

 By Prof. D. N. Mallik, B.A., Sc.D., F.B.S.E* 



1. TXTHEN an electric discharge is passed through a 

 ▼ ▼ De La Rive's tube at different pressures, it is 

 found (" Magnetic Potation of Electric Discharge," Phil. 

 Mag. Oct. 1908) :— 



1. That there are three stages of the discharge : At a high 

 pressure, the discharge is in the form of a shower, con- 

 sisting of an infinite number of rays. These, gradually, — as 

 the pressure is diminished — form into a single band or 

 stream ; as the pressure is further reduced, the band broadens 

 and ultimately fills the whole tube as a glow discharge. 



2. Now an electric discharge is a procession of corpuscles 

 shot off from the negative electrode under the influence of 

 the electric field and ions, positive and negative, produced 

 by collision of these corpuscles with the molecules of the 

 enclosed gas. 



The ions and the corpuscles exert electric force on one 

 another, and as they are in motion they exert a magnetic 

 force as well. Moreover, these masses moving through the 

 fluid medium must exert an additional apparent force on 

 one another, besides experiencing a viscous retardation in 

 the direction of motion. 



The effect of these forces along a line of discharge affects 

 motion and collision along the line, and therefore need not 



* Communicated by the Author. 



