tJie Rev. John Flamsteed. 189 



the public relative to Flamsteed's publishing the Catalogue, upon 

 which it now became well known that he was deeply engaged ; 

 and, amongst others, Newton also suggested to him (by letter 

 dated August 10, 1691), only two years after the mural arc had 

 been in use, the utility of publishing the places of a few of the 

 principal stars, before the completion of the whole catalogue. 

 Flanrreteed, in his reply, justifies the course he is pursuing, and 

 points out the inconvenience and difficulty that would arise, if 

 he were to adopt a different line of conduct.* This answer of 

 Flamsteed, however, is remarkable and interesting, as giving us 

 the first intimation of the breach between himself and Halley \ 

 and, if we may judge from the tenor of Flamsteed''s language, 

 the quarrel had already proceeded to a great length.*f* Flam- 

 steed's intimacy with Newton, however, does not appear to have 

 suffered any diminution on this account ; for we find that, soon 

 after this, when Newton had again turned his attention towards 

 the lunar theory ,J he paid a visit to the Observatory, on Septem- 

 ber 1, 1694, where Flamsteed, "esteeming him to be an obliged 

 friend,"" explained to him what progress he had made in his ca- 

 talogue, and in his lunar and planetary investigations ; and also 

 shewed him about 150 computed places of the moon, with their 



• See Newton's Letter, in the Appendix, No. 14, and Flamsteed's Answer 

 thereto, in No. 15. Had Flamsteed published his catalc^e at this time, he 

 would have fallen into the very same error that Halley did ; who, having de- 

 termined the intermutual distances of the southern stars by means of the sex- 

 tant only, was obliged to depend on Tycho's observations for his fundamental 

 points, and has thus given us a catalogue, which is of no use whatever to the 

 practical astronomer. It was reserved for Mr Abraham Sharp to perfect what 

 Halley had neglected to perform. 



•f- I have not been able to ascertain the precise cause of the quarrel between 

 Halley and Flamsteed. They were certainly of very different habits and 

 manners, and not likely to accord on many points. It would seem, from some 

 documents inserted in the Appendix, No. 54, that Flamsteed suspected that 

 Halley had obtained, in a surreptitious manner, the magnetical papers of Mr 

 Perkins, the mathematical master at Christ-Church Hospital, and published 

 them as his own ; and perhaps Flamsteed mentioned his opinion upon this 

 subject rather too freely. I find that Fiamsteed's private sentiments were, 

 that this was not the only instance in which Halley had pirated firom other 

 persons. (See page 150.) 



X This was after the attack of illness with which Newton waa ao seriously afL 

 flicted, as to lead (in the opinion of some persons) to a temporary abemu 

 tion of mind. 



