1893.J President's Address. 381 



Voltaire, during a visit which he made to England in 1727, 

 wrote : " A Frenchman who arrives in London finds a great alteration 

 in philosophy, as in other things. He left the world full ; he finds 

 it empty. At Paris you see the universe composed of vortices of 

 subtle matter; at London we see nothing of the kind. With you 

 it is the pressure of the Moon which causes the tides of the sea ; in 

 England it is the sea which gravitates towards the Moon. . . . You 

 will observe also that the Sun, which in France has nothing to do 

 with the business, here comes in for a quarter of it. Among you 

 Cartesians all is done by impulsion : with the Newtonians it is done 

 by an attraction of which we know the cause no better."* Indeed, 

 the Newtonian opinions had scarcely any disciples in France till 

 Voltaire asserted their claims on his return from England in 1728. 

 Till then, as he himself says, there were not twenty Newtonians out 

 of England.! 



In the second quarter of the century sentiment and opinion in 

 France, Germany, Switzerland, and Italy experienced a great change. 

 The mathematical prize questions proposed by the French Academy 

 naturally brought the two sets of opinions into conflict. A Cartesian 

 memoir of John Bernoulli was the one which gained the prize in 

 1730. It not infrequently happened that the Academy, as if desirous 

 to show its impartiality, divided the prize between Cartesians and 

 Newtonians. Thus, in 1734, the question being the cause of the in- 

 clination of tbe orbits of the planets, the prize was shared between 

 John Bernoulli, whose memoir was founded on the system of vortices, 

 and his son Daniel, who was a Newtonian. The last act of homage 

 of this kind to the Cartesian system was performed in 1740, when the 

 prize on the question of the tides was distributed between Daniel 

 Bernoulli, Euler, Maclaurin, and Cavallieri ; the last of whom had 

 tried to amend and patch up the Cartesian hypothesis on this 

 subject. J 



On the 4th of February, 1744, Daniel Bernoulli wrote as follows to 

 Euler : " Uebrigens glaube ich, dass der Aether sowohl gravis versus 

 solem, als die Luft versus terrain sey, und kann Ihnen night bergen, 

 dass ich iiber diese Puncte ein volliger Newtonianer bin, vnd verwun- 

 dere ich mich, dass sie den Principiis Cartesianis so lang adhariren ; 

 es mochte wohl einige Passion vielleicht mit unterlaufen. Hat Gott 

 konnen eine animam, deren Natur uns unbegreiflich ist, erschaffen, so 

 hat er auch konnen eine attractionem universalem materiae im- 

 primiren, wenn gleich solche attractio supra captum ist, da hingegen 

 die Principia Cartesiana allzeit contra captum etwas involviren." 



Here the writer, expressing wonder that Euler had so long adhered 



* Whewell's 'History of the Inductive Sciences,' vol. 2, pp. 202203. 



f Ibid., vol. 2, p. 201. 



t Ibid., vol. 2, pp. 198, 199. 



