12 Wilde, Evohition of the Metital Faculties. 



motion is exhausted. But this proves that a body with a 

 double velocity moves with a double force, since it is 

 produced or destroyed by the same uniform power 

 continued for a double time, and not with a quadruple 

 force, though it arise to a quadruple height." He adds 

 that " This, however, was the argument upon which Mr. 

 Leibnitz first built this doctrine."* 



The controversy that has since raged round this 

 question, and which is still unsettled, forms a remarkable 

 chapter in the history of the physical sciences. As might 

 have been anticipated, a priori philosophers, mathe- 

 maticians, metaphysicians, and men of letters, unskilled in 

 experimental methods of interrogating nature, adopted 

 the vulgar measure of moving force. Of these may be 

 mentioned, besides Maclaurin, Emerson, Hutton and 

 Young ; Locke, Kant, Schopenhauer, Reid and Voltaire. 

 Happily for the progress of science a small number of 

 philosophers, among whom Smeaton and Wollaston stand 

 pre-eminent, proved conclusively, by various methods, 

 that the true measure of the moving force of a body under 

 the free action of gravity is as the square of the velocity. 

 Nevertheless, modern scholasticism has not yet pronounced 

 in favour of the law, at least in this country, and the 

 ingenuous youth of universities and schools are still left 

 in error and ignorance of a principle of motion which lies 

 at the very root of the natural sciences. 



An unpleasant feature of this controversy was the 

 arrogance with which the experimental results of Smeaton 

 and Wollaston were treated by their opponents, and in 

 this respect a close parallel is found in the attitude of 

 seventeenth-century science towards the Copernican 

 system of astronomy. 



The facts adduced by the earlier supporters of the 



* Account of Newton's Philosophical Discoveries^ 1748, p. 135- 



