Astronomy and Electrical Theory of Matter. 321 



tt = l*5 for dishes nearly brimful, then the linear evaporation 

 will vary inversely as the square root of the radius of the 

 vessel used. This is possibly an important factor in ex- 

 plaining the irregularities observed in the linear evaporation 

 from comparatively small surfaces. 



Our thanks are tendered to Professor E. Taylor Jones of 

 the University College of North Wales in whose laboratory 

 most of the experimental work was carried out, and to 

 Professor V. H. Blackman of the Imperial College of 

 Science and Technology to whom we are indebted for 

 several references to the literature of the subject. 

 August 1917. 



XXXII. Astronomical Consequences of the Electrical Theory 

 of Matter. Note on Sir Oliver Lodge's suggestions, II. 

 By Prof. A. S. Eddington, ALA., F.RS., Plumian 

 Professor of Astronomy in the University of Cambridge* . 



1. O IP OLIVER LODGE's theory, given in the August 

 O number of this Magazine, makes use of the well- 

 known equation of particle dynamics, 



d 2 u _ F/m . 



dd 2+u -JiSi 2 W 



In the course of correspondence between us, it has appeared 

 that this equation requires amendment when m is taken as 

 variable. If we recall the steps by which it is obtained in 

 text-books, we find that m has been assumed constant ; and 

 it is therefore necessary to examine the effect of the terms 

 in dm/dt which have been left out. 



Since Lodge's theory is a non-relativity theory, it is 

 essential to refer all such quantities as momentum to axes 

 fixed in the sether, and not to axes travelling with the sun. 

 But I think it will be clearer if I divide the work into two 

 stages, using first momenta relative to the sun, and after- 

 wards introducing the further terms which appear when we 

 refer (as we ought) to fixed axes. 



The radial and transverse components of momentum are 

 then 



h± = mr, h 2 = mr6, 



where m is the inertia, which varies with the velocity of the 

 planet relative to the sether. The rates of change of momenta 



* Communicated by Sir Oliver Lodge. 



