THE ASTRONOMICAL VIEW OF NATURE. 373 



regarding the equivalence of closed electrical currents 

 with magnets. This led, first, to the reduction of all 

 magnetic effects to the action of electrical currents; and, 

 secondly, to the enunciation of a fundamental law of the 

 interaction of two elements of electricity in motion. A 

 third leading idea was that of reducing the interaction 

 of all bodies to that of the mutual action of pairs of 

 bodies. This idea could in general be considered as 

 well established and confirmed by experience on a large 

 scale." l 



This leads me to another and a final remark on the 

 view of natural phenomena, first introduced by New- 

 ton's gravitation formula, which has been so success- 

 ful in the calculation of all the movements of cosmic 39. 



Necessity of 



bodies, and which in the eyes of such a great authority Developing 



J the mflm- 



as Laplace contained the clue to an explanation also of ^{^ds 

 molar and molecular phenomena. 2 This view calculates 



1 ' Electrodynamische Maasbes- 

 tirnmungen,' 1878, p. 645. 



2 Although Weber followed the 

 lines so deeply impressed upon the 

 whole of Continental thought by 

 the labours of Laplace and his 

 school, it does not seem that he 

 held the same exalted opinion of 

 the value of any mathematical for- 

 mula as did Laplace. Though he 

 looked upon his electro - dynamic 

 law as well established by experi- 

 ment and valuable in guiding 

 further research, he was fully im- 

 pressed with the fact that all such 

 formulae are merely provisional. 

 Thus he says in the first part of 

 his researches, written in the year 

 1846: "It seems to follow that 

 the immediate interaction of two 

 electrical particles does not depend 

 upon these alone, but also upon the 

 presence of third bodies. ... It is 



conceivable that the forces com- 

 prised in the discovered funda- 

 mental law may be partly the 

 forces which two electrical particles 

 exert indirectly on each other, and 

 which therefore depend on the in- 

 tervening medium. . . . The general 

 law for the determination of the 

 acting forces might perhaps be yet 

 more simply expressed by taking 

 the intervening medium into ac- 

 count, than has been possible 

 without it in the fundamental 

 law now established. The explora- 

 tion of the intervening medium, 

 which might afford an insight into 

 many other matters, can alone give 

 an answer to this question. ... A 

 hope now exists that it will be 

 possible, in several new ways, to 

 gain some information as to the 

 neutral electric fluid which per- 

 vades everything. Perhaps in 



