5kt.iv] DISSERTATION SECOND. 117 



» 



which they revolved. The imaginary apparatus of cycle* 

 and epicycles, — the immobility of the earth, — the supposed 

 essential distinction between celestial and terrestrial sub- 

 stances, those insuperable obstacles to real knowledge, 

 which the prejudice of the ancients had established as 

 physical truths, were entirely removed ; and Bacon had 

 taught the true laws of philosophising, and pointed out the 

 genuine method of extracting knowledge from experiment 

 and observation. The leading principles of mechanics 

 were established ; and it was no unimportant circumstance, 

 that the Vortices of Descartes had exhausted one of the 

 sources of error, most seducing on account of its simpli- 

 city. 



All this had been done when the genius of Newton 

 arose upon the earth. Never till now had there been set 

 before any of the human race so brilliant a career to run, 

 or so noble a prize to be obtained. In the progress of 

 knowledge, a moment had arrived more favourable to the 

 developement of talent than any other, either later or ear- 

 lier, and in which it might produce the greatest possible 

 effect. But, let it not be supposed, while 1 thus admit the in- 

 fluence of external circumstances on the exertions of intel- 

 lectual power, that I am lessening the merit of this last, or tak- 

 ing any tiling from the admiration that is due to it. I am, in 

 truth, only distinguishing between what it is possible, and what 

 it is impossible, for the human mind to effect. With all the 

 aid that circumstances could give, it required the highest 

 degree of intellectual power to accomplish what Newton 

 performed. We have here a memorable, perhaps a sin- 

 gular instance, of the highest degree of intellectual power, 

 united to the most favourable condition of things for its 

 exertion. Though Newton's situation was more favourable 

 than that of the men of science who had gone before him, it 

 was not more so than that of those men who pursued the 



