MEANING OF TERMS AND SYMBOLS AS USED 

 IN THIS BOOK.. 



Electron = the unit electric charge, or atom of negative electricity. 

 e =the amount of this charge, whether positive or nega- 

 tive; about 3xlO~ 10 electrostatic unit. 

 E =an electromotive force, or the strength of an electric 



field. 



H = the strength of a magnetic field. 

 m = mass or inertia, especially the mass of an electron. 

 a = usually, the linear dimension of an electron (about the 



hundred-thousandth of b). 



b =the linear dimension of an atom of matter (the ten- 

 millionth of a millimetre). 



ion = an atom of matter with an unbalanced electric charge, 

 either negative or positive, attached to it : the 

 cause of chemical affinity. 

 K = Faraday's dielectric constant, or the specific inductive 



capacity of free ether. 

 P = the magnetic permeability of free ether. 



[These two are the great ethereal constants, whose 

 value and nature are not yet known. Only their 

 product is known.] 

 v =the velocity of light in vacuo 



= 3 x 10 10 cm. per sec. 

 u = the velocity of a particle. 



