4GG Sir Oliver Lodge on a possible means of determining 



There are also some expressions which are really time, 

 namely RS, L/R, and V^(LS). And there is also the 

 remarkable relation \/(l/yu,K) which dominates optics and 

 is really a velocity. It follows that the product em is 

 really angular momentum, or of the same dimension as 

 Planck's constant A. 



fit is even of interest to reckon the purely numeric:)! 

 relation between e^iii and A, where e 1 is the charge of an 

 electron, and m-^ some corresponding unit magnetic pole 

 which might be called a magneton. When an electron 

 in an atom is revolving so fast that it flies otf, these 

 quantities are brought into relation with the quantum', 

 and since 47rm is the total induction from a pole, and 

 Aire the total lines of force from a charge, and h^lnr the 

 angular momentum of a revolving electron ready to escape 

 from an atom so that its energy comes within our range of 

 observation, it is natural to write 



4:7rm 1 x 4c7re 1 = /</27r 



or A = 327r 3 e 1 m 1 . 



To see if the order of magnitude here involved is at all 

 right, we can utilize the known relation ni=five, and take v 

 as practically the speed of light, c, for an escaping /3 ray. 



Now A has been measured as 



6-547 xlO-^c.g.s.CMI^T- 1 ), 



while Professor Millikan's measure of 



e is 4*774 X 10~ 10 electrostatic unit. 



Hence e^^fic^ 2 = e^/Kc- 7-6 x l0- 30 c.g-.s. (ML 2 T- J ) *. 



It will be seen that 327r 3 times this quantity gives an A of 

 the right order of magnitude, though a little too big, namely 

 7*5 xlO -27 . But the agreement is sufficiently near to be 

 striking. To make it exact we should have to consider the 

 electronic charge as 



e 1 = 4*36 X 10~ 10 electrostatic unit. 



Or, if we take A and e, above, as both correctly mea- 

 sured, and fjuv <?j 2 = A/32 7r 3 , we can reckon the velocity 

 with which an electron is revolving before it escapes, as 

 v = 2'6l x 10 10 cm. per sec] 



In passing we may note that electromotive force is m/t 



* The above e L m 1 is the angular momentum of a sphere the size of 

 electron and density 10 ~ 12 revolving on its own axis with an equatorial 

 speed of light. 



