20 FORESHADOWING OF THE ATOM [CH. in. 



charges, for then we shall have obtained a secure 

 basis on which to form a true theory of electric 

 currents, and so become independent of these 

 provisional theories." 



It is rash to predict what may ultimately happen, 

 but the present state of electrical science seems hostile 

 to this latter prediction of Maxwell. The theory of 

 molecular charges looms bigger to-day, and has taken 

 on a definiteness, largely as the outcome of his 

 own work, that would have pleased and surprised 

 him. 



The unit electric charge, the charge of a monad 

 atom in electrolysis, whatever else it is, is a natural 

 unit of electricity, of which we can have multiples, 

 but of which, so far as we know at present, it is 

 impossible to have fractions. 



I will extract the following sentence from Section 

 32 of my little book called Modern Views of 

 Electricity (1889. See also Brit. Assoc., Aberdeen, 

 1885, p. 763): 



" This quantity, the charge of one monad 

 atom, constitutes the smallest known portion of 

 electricity, and is a real natural unit. Obviously 

 this is a most vital fact. This unit, below which 

 nothing is known, has even been styled an 

 ' atom of electricity,' and perhaps the phrase 

 may have some meaning. . . . This natural 

 unit of electricity is exceedingly small, being 

 about the hundred-thousand-millionth part of 

 the ordinary electrostatic unit,: or less than the 

 hundred- trillionth of a coulomb." 



The atom with its charge is called an " ion." The 

 charge considered alone, without attending to its 



