The Discharge of Electricity through Gases. 545 



up to the electrode, which may not be justifiable ; but another expla- 

 nation is possible. If we ask at what distance from the kathode is 

 the potential 1 volt less than at the kathode itself, we find it to be 

 about the thousandth part of a millimeter. It will constantly 

 happen that particles will approach the kathode from that distance, 

 and the work which has to be done in the transference of the positive 

 ion to the electrode may be partially supplied by the energy acquired 

 in the fall. 



Effect of a Magnet on the Negative Discharge. 

 Confirmation of the Theory. 



In my former paper I described a method by means of which I 

 hoped to be able to measure the charges carried by the ions, and thus 

 directly to test the truth of the theory. It is clearly most desirable 

 that this should be done, for if it could be shown that the molecular 

 •charges are the same as those carried by the atoms in electrolytes, all 

 further doubt as to the correctness of the view which I advocate 

 would vanish. I have met with very considerable difficulties in the 

 attempt to carry out the measurements in a satisfactory manner, 

 and have only hitherto succeeded in fixing somewhat wide limits 

 between which the molecular charges must lie. 



According to one theory, particles are projected from the kathode. 

 The observed effect of the magnet on them is exactly what it should 

 be under the circumstances. The path of the particles can be traced 

 by means of the luminosity produced by the molecular impacts. 

 If the trajectory is originally straight, it bends under the influence of 

 a magnet. The curvature of the rays depends on two unknown 

 quantities, the velocity of the particles and the quantity of electricity 

 they carry. 



If the particles carrying a charge are moving with velocity at right 

 angles to the lines of force, the radius of curvature r is determined 

 by the equation 



= Mve or — = — - (1.), 



r m Mr 



where m is the mass of the particle. If the particles originally at 

 rest, start from the kathode at which the potential is taken as zero, 

 and arrive, without loss of energy, at a place where the potential is 

 V, we should have another equation, namely : — 



2Ye = mo* . (2.). 



Eliminating v, we find : — 



1 = 2Y_ (3 .). 



