196 Faraday. 



we can picture this vector as being of the nature of a displace- 

 ment. By such an assumption we should avoid altogether the 

 necessity for regarding the conduction-current as an actual 

 flow of electric charges, or for speculating whether the drifting 

 charges are positive or negative ; and there would be no longer 

 anything surprising in the production of a null effect by the 

 coalescence of electric charges of opposite signs. 



Faraday himself wished to leave the matter open, and to 

 avoid any definite assumption.* Perhaps the best indication of 

 his views is afforded by a laboratory notej- of date 1837 : 



"After much consideration of the manner in which the 

 electric forces are arranged in the various phenomena generally,. 

 I have come to certain conclusions which I will endeavour to 

 note down without committing myself to any opinion as to the 

 cause of electricity, i.e., as to the nature of the power. If 

 electricity exist independently of matter, then I think that the 

 hypothesis of one fluid will not stand against that of two fluids. 

 There are, I think, evidently what I may call two elements of 

 power, of equal force and acting toward each other. But these 

 powers may be distinguished only by direction, and may be no 

 more separate than the north and south forces in the elements 

 of a magnetic needle. They may be the polar points of the 

 forces originally placed in the particles of matter." 



It may be remarked that since the rise of the mathematical 

 theory of electrostatics, the controversy between the supporters 

 of the one-fluid and the two-fluid theories had become 

 manifestly barren. The analytical equations, in which 

 interest was now largely centred, could be interpreted equally 

 well on either hypothesis; and there seemed to be little 

 prospect of discriminating between them by any new experi- 

 mental discovery. But a problem does not lose its fascination 



*"His principal aim," said Helmholtz in the Faraday Lecture of 1881, 

 " was to express in his new conceptions only facts, with the least possible use of 

 hypothetical substances and forces. This was really a progress in general 

 scientific method, destined to purify science from the last remains of meta- 

 physics." 



t Bence Jones's Life of Foradny^ ii, p. 77. 



