382 Anniversary Meeting. [Nov. 30, 



to the Cartesian principles, declares himself a thorough- going New- 

 tonian, not merely in respect to gravitation versus vortices, but in 

 believing that matter may have been created simply with the law 

 of universal attraction without the aid of any gravific medium or 

 mechanism. But in this he was more Newtonian than Newton, him- 

 self. 



Indeed Newton was not a Newtonian, according to Daniel Ber- 

 noulli's idea of Newtonianism, for in his letter to Bentley of date 

 25th February, 1692,* he wrote : " That gravity should be innate, 

 inherent, and essential to matter, so that one body may act upon 

 another at a distance through a vacuum without the mediation of 

 anything else, by and through which their action and force may be 

 conveyed from one to another, is to me so great an absurdity that I 

 believe no man who has in philosophical matters a competent faculty 

 of thinking can ever fall into it." Thus Newton, in giving out his 

 great law, did not abandon the idea that matter cannot act where it 

 is not. In respect, however, merely of philosophic thought, we must 

 feel that Daniel Bernoulli was right ; we can conceive the Sun at- 

 tracting Jupiter, and Jupiter attracting the Sun, without any inter- 

 mediate medium, if they are ordered to do so. But the question 

 remains Are they so ordered ? Nevertheless, I believe all, or 

 nearly all, his scientific contemporaries agreed with Daniel Bernoulli 

 in answering this question affirmatively. Very soon after the middle 

 of the eighteenth century Father Boscovichf gave his brilliant 

 doctrine (if infinitely improbable theory) that elastic rigidity of 

 solids, the elasticity of compressible liquids and gases, the attractions 

 of chemical affinity and cohesion, the forces of electricity and magnet- 

 ism in short, all the properties of matter except heat, which he attri- 

 buted to a sulphureous fermenting essence are to be explained by 

 mutual attractions and repulsions, varying solely with distances, 

 between mathematical points endowed also, each ojf them, with inertia. 

 Before the end of the eighteenth century the idea of action-at-a-dis- 

 tance through absolute vacuum had become so firmly established, and 

 Boscovich's theory so unqualifiedly accepted as a reality, that the idea 

 of gravitational force or electric force or magnetic force being pro- 

 pagated through and by a medium seemed as wild to the naturalists 

 and mathematicians of 100 years ago as action-at-a-distance had 

 seemed to Newton and his contemporaries 100 years earlier. But a 

 retrogression from the eighteenth century school of science set in 

 early in the nineteenth century. 



Faraday, with his curved lines of electric force, and his dielectric 



** * The Correspondence of Richard Bentley, D.D.,' vol. 1, p. 70. 



f Theoria Philosophies Naturalis redacta ad unicam legem virium in natura 

 existentium auctore P. Bogerio Josepho Boscovich, Societatis Jesu,' 1st edition, 

 Vienna, 1758 ; 2nd edition, amended and extended by the author, Venice, 1763. 



