1 40 Mr Bail}''s Account of 



differences from the places observed, at that time a most valu- 

 able document ; copies of which he gave to Sir Isaac, for his 

 private use to rectify the lunar theory ; on this express condi- 

 tion, however, that he should not impart them (or the results 

 obtained therefrom) to any person without Flamsteed''s consent, 

 for this obvious and just cause, that the places of the moon 

 were determined only by means of his approximate catalogue 

 above mentioned.* This interview led to a correspondence be- 

 tween them relative to this and other astronomical subjects, the 

 major part of which has never before been made public.-|- In 

 the spring of 1696, Newton was made AVarden of the Mint, 

 and came then to reside in London ; where Flamsteed says, 

 that he sometimes visited him in Jermyn Street ; that they con- 

 tinued civil towards each other, but that Newton was not so 

 friendly as formerly. Here, then, we trace the first symptoms of 

 that coolness between them which soon afterwards broke out 

 into an open rupture, the immediate cause of which appears to 

 be as r.)llows. 



DrWallis having understood that Flamsteed had written a paper 

 '' On the Parallax of the Earth'*s Annual Orb,*' requested a copy 

 of it, for the purpose of its being published in the third volume 

 of his Mathematical Tracts, then in the press.J Flamsteed ac- 



• This request was not only reasonable but mutual; for Newton frequently 

 enjoined the same restrictions upon Flamsteed. In one of his letters (No. 25. in 

 the Appendix) he proposes to send Flamsteed a new table for the moon, on the 

 express condition that he shall keep it to himself till Newton has perfected 

 the lunar theory, because it would need correction ; and that Newton ac- 

 knowledged Flamsteed's claim, is evident from a letter which he wrote about 

 the same period (No. 20. in the Appendix), wherein Newton says, " I only 

 assure you at present that, without your consent, I will neither publish them 

 nor communicate them to any body whilst you live, nor after your death, 

 without an honourable acknowledgment of their author." 



-|- These letters are now given in the Appendix, No. 16-34. Some of New- 

 ton's letters, more especially Nos. 30. and 31. do not seem to have been writ- 

 ten in a very courteous style. Indeed, Flamsteed has remarked that Newton's 

 conversation was not always of the most engaging kind, since he was some- 

 times so presumptuous as to ask him " why he did not hold his tongue." — 

 (See page 73.) 



X This is the celebrated letter of Dr Wallis, in which Flamsteed clearly 

 points out the effect of Aberration ; and indeed defines its amount, which ac- 

 cords remarkably well with modem observations. A similar effect had been 

 noticed, may years previous thereto, both by Hooke and by Picard, almost 



