ACTION AT A DISTANCE. 317 



la impossible. He did not forget, however, to endow his mathematical points 

 with inertia. In this some of the modern representatives of his school have 

 thought that he " had not quite got so far as the strict modern view of 

 'matter* as being but an expression for modes or manifestations of 'force'""." 



But if we leave out of account for the present the development of the 

 ideas of science, and confine our attention to the extension of its boundaries, we 

 shall see that it was most essential that Newton's method should be extended 

 to every branch of science to which it was applicable that we should investi- 

 gate the forces with which bodies act on each other in the first place, before 

 attempting to explain how that force is transmitted. No men could be better 

 fitted to apply themselves exclusively to the first part of the problem, than 

 those who considered the second part quite unnecessary. 



Accordingly Cavendish, Coulomb, and Poisson, the founders of the exact 

 sciences of electricity and magnetism, paid no regard to those old notions of 

 "magnetic effluvia" and "electric atmospheres," which had been put forth in 

 the previous century, but turned their undivided attention to the determination 

 of the law of force, according to which electrified and magnetized bodies attract 

 or repel each other. In this way the true laws of these actions were dis- 

 covered, and this was done by men who never doubted that the action took 

 place at a distance, without the intervention of any medium, and who would 

 have regarded the discovery of such a medium as complicating rather than as 

 explaining the undoubted phenomena of attraction. 



We have now arrived at the great discovery by Orsted of the connection 

 between electricity and magnetism. Orsted found that an electric current acts 

 on a magnetic pole, but that it neither attracts it nor repels it, but causes it 

 to move round the current. He expressed this by saying that "the electric 

 conflict acts hi a revolving manner." 



The most obvious deduction from this new fact was that the action of the 

 current on the magnet is not a push-and-pull force, but a rotatory force, and 

 accordingly many minds were set a-speculating on vortices and streams of sether 

 whirling round the current. 



But Ampere, by a combination of mathematical skill with experimental 

 ingenuity, first proved that two electric currents act on one another, and then 

 analysed this action into the resultant of a system of push-and-pull forces 

 between the elementary parts of these currents. 



* Review of Mrs Somerville, Saturday Review, Feb. 13, 1869. 



