66 Dr J. C. GREGORY'S Notice concerning 



state of mental derangement; but to shew on what slender 

 grounds this allegation rests, it may be mentioned, that M. BIOT 

 seems to find an argument in its favour in the magnanimity with 

 which NEWTON bore the irreparable loss of the labour of many 

 years ! And, as a proof that his mental powers were not impair- 

 ed, either by this accident, or by the advance of years, it may be 

 sufficient to allude to the fact, admitted by M. BIOT himself, 

 that, in the year 1716, and at the age of 74, NEWTON, on re- 

 turning from his duties at the Mint, and when much fatigued 

 with the business of the day, solved, before he retired to rest, 

 the celebrated problem of Orthogonal Trajectories, proposed by 

 LEIBNITZ with a view to prove the superiority of his calculus 

 over NEWTON'S method of fluxions, and, as he expresses him- 

 self, " ut pulsum Anglorum Analystarum nonnihil tentemus *." 



As Sir ISAAC NEWTON'S Observations on the Prophecies and 

 the Apocalypse were not published during his lifetime, and as 

 the celebrated general Scholium at the end of the Principia only 

 appeared in the second edition of that work, published in 1713, 

 when the author was in his 71st year, the supposition entertained 

 by LA PLACE, that NEWTON only turned his attention to the 

 subject of theology in his very advanced years, is somewhat more 

 natural and plausible in the absence of any direct evidence to the 

 contrary. So impressed was he with this idea, that M. GAUTIER, 

 Professor of Astronomy in Geneva, mentioned, when in this coun- 

 try a few years ago, that he had been commissioned by LA PLACE 

 to make inquiries on this subject. Any opinion entertained by 

 this great man, by whose genius and labours the Newtonian 

 Philosophy may be said to have been completed in all its details, 

 is entitled to due respect and attention from all, and, in the 

 minds of many, must carry with it considerable weight. A do- 



* LEIBNITII et BERNOULLII Commercium Epistolicum, torn. ii. Epist. ccxxvi. 

 p. 365. 



