On the Steady Motion of an Electrified Ellipsoid. 329 

 single-ray velocity be taken as the axis of x" we have 



(°^ x m + b 2 A {x"* +y 2 ) - '2aW 2 - b* (o 2 + d 2 ),/ + aW = 



as the equation to the curves. 



Section containing the axis of single-ray velocity and 

 the axis of y. 



Inner 



. 



i 



Outer 



. 



x" 



y- 



x". 





y- 



0-00 



2-00 



o-oo 





4-00 



1-00 



1-85 



1-00 





3-85 



M6 



1-80 



1-16 





3-80 



1-59 



1-59 









2-00 



1-33 



2-00 





3-32 



2-32 



1-05 



2-32 

 2-65 





3-03 

 2-65 



2-37 



1-00 



3-18 





1-00 



2-75 



0-50 



3-14 





0-50 



3-00 



o-oo 



3-00 





0-00 









and 1-97 



Angles are given to the nearest 10', and the other numbers 

 to the second decimal place. 



XL 1 1. On the Steady Motion of an Electrified Ellipsoid. 

 By G. F. C. Searle, M.A., Demonstrator in Experimental 

 Physics, Cavendish Laboratory, Cambridge *. 



AT the Meeting of the Royal Society on 19th March, 

 1896, I read a paper on " Problems in Electric Con- 

 vection." The first part of the paper is printed in the 

 'Philosophical Transactions of the Royal Society 'f, and 

 contains the principles which are required in the solution of 

 any problems about moving charges. The second part of 

 the paper, which deals with the motion of a charged ellipsoid, 

 was not published by the Royal Society. A few of the 

 results are, however, stated in an abstract published in the 

 ' Proceedings ' %. By the permission of the Royal Society I 

 now publish my results for a moving ellipsoid. As frequent 

 reference to my paper in the ' Philosophical Transactions ' 

 will be necessary, 1 shall use the notation {§5} and {(9)} to 

 indicate the paragraph or equation referred to in that paper. 



* Communicated by the Physical Society : read June 25, 1897. 

 t Phil. Trans, vol. 187 (1896) A. pp. 675-713. 

 % Pvoc. Roy. Soc. vol. 59, p. 343. 



