( 430 ) 



bein^ the electric force. By both signs I shall now denote, not the 

 whole vector, but the part that is due to the vibrations. 



The equations may again be written in a form in which tlie 

 velocity of translation does not explicitly appear. For this purpose, 

 it is necessary to replace the variables a;', }j\ z\ i\ 5', -0', a and Cq 

 by new ones, differing from the original quantities by certain con- 

 stant factors. 



For the sake of uniformity of nutation all tiiese new variables 

 will be distinguished by double accents. Let t be an indeterminate 

 coefficient, ditfering from unity by a quantity of the order vV'/F^, 

 and let us put 



■«■ = y •'■") U — f ,'/'» z = tc" , (6) 



>1t = — a r, <\,/ :=z ^ a ,,, il- =: f a'- , . . . . (7) 



k 



k „ 



Co = TT i'u (8) 



^ _ 1 ,„ ^, 1 ,, ^^ 1 



k h k 



f = /cf- I" , (9) 



so that t" is a UKidilicii hical time; Ihcii we lind 



JMr" .b"=z , (ii;,) 



3 •?>"-- 3-P".'/ , „9 «".'•, 1 3a'V ^ ^....^ 



1/ a i d t V ~ d t 



3g". dTs",, 9.CV'/ 



^ -— - = — -- , etc (I Vc) 



d y as' ot 



