G10 Mr. G. H. Livens on the Initial Accelerated 



discharge observed when the salt is heated on platinum may 

 have its origin in this carbon. The experiments described 

 above, however, suggest that the platinum plays an important 

 role in the ionization of the carbon monoxide and other pro- 

 ducts formed by heating platinum or platinum coated with 

 aluminium phosphate. 



Summary. — (a) The activity of platinum is not reduced by 

 continued heating merely, but only under conditions which 

 admit o£ a positive discharge from the metal. The loss of 

 activity is therefore due to the diminution of the quantity 

 of matter — carbon, carbon monoxide, or whatever it may be — 

 which emerges from the platinum in the form of positive ions 

 at sufficiently high temperatures. (6) The activity is greatly 

 increased by heating the platinum in the presence of water. 

 This effect is possibly due to the production of carbon 

 monoxide and hydrogen in the platinum or at its surface, 

 and can be observed even when the platinum is heated in a 

 dry atmosphere, provided it has been previously heated and 

 allowed to cool in an atmosphere saturated with aqueous 

 vapour. 



(c) There is apparently no positive leak (or only a very 

 small one) when aluminium phosphate is heated on a Nernst 

 filament, and therefore the leak observed when the salt is 

 heated on platinum is either mainly a leak from the platinum 

 itself, or the latter plays an important role in its production. 



Further research on the subject is being carried out, of 

 which a full account will be published later. 



Wheatstone Laboratory, 



University of London, King's College. 



February 1911. 



LXXV. The Initial Accelerated Motion of a Perfectly Con- 

 ducting Electrified Sphere. By G. H. Livens, B.A., 

 Lecturer in Mathematics, Sheffield University *. 



SEVERAL papers have recently been published dealing 

 with this subject ; those particularly under review here 

 are by G. W. Walker (Proc. K. S. vol. lxxvii. and Phil, 

 Trans. 1910). 



In the present paper the same subject is dealt with in a 

 manner similar to that given by Walker, but the complica- 

 tions of considering any material mass that the sphere may 

 possess are entirely avoided, the subject being discussed 

 purely from the electromagnetic standpoint. The use of 



* Communicated by the Author. 



