410 Life of the Rev. John Flamsteed, [Dec. 



Sir Jonas Moore sometimes wrote to me ; and, in his 

 letters, testified the pleasure he took in the success of my 

 endeavours, and in what I imparted to Mr. Oldenburg, and 

 was printed by him in the Philosophical Transactions. 



By Mr. Oldenburg's means I changed some letters with 

 M. Cassini. Having no longer glasses yet than of thirteen 

 feet, I had not taken notice that the body of Jupiter was 

 not perfectly round ; and in one of my letters affirmed that, 

 to me, he appeared always round, which he took notice of; 

 and which caused me to consider him more attentively. 

 And, in my view afterwards in the same glass of thirteen 

 feet, I saw I had reason to suspect my heedless assertion ; 

 and, when I came to employ longer glasses, that he was 

 (as Cassini had asserted) oval. 



Besides the observations I imparted to Mr. Oldenburg, 

 I took others that might be of use to me afterwards : though, 

 because the times were not so accurate as I thought was 

 requisite, I did not publish them. 



In 1673, besides my usual task, I wrote an Ephemeris, 

 wherein I showed the falsity of Astrology, and the ignorance 

 of those who pretended to it : wherein I gave a table of the 

 moon's risings and settings, carefully calculated ; together 

 with the eclipses and appulses of the moon and planets to 

 fixed stars. This fell into the hands of Sir Jonas Moore, 

 for whom (at his request) I made a table of the moon's true 

 southings for that year. From which, and Mr. Phillip's 

 theory of the tides, the high-water being made, he found 

 they showed the times of the turn of the tides very near : 

 whereas the ordinary seamens coarse rules would err some- 

 times two or three hours. It was the summer of the follow- 

 ing year, 1674, that I came to London, in my way to Cam- 

 bridge ; whither Sir Jonas Moore (hearing of my intent) 

 invited me, and where he received me very kindly : told 

 me how acceptable a true account of the Tides would be to 

 his then Majesty King Charles II. ; off*ered me the help of 

 his servant to make this table or any other work of the like 

 nature. We resolved together to compose a small ephe- 

 meris for his Majesty's use : which was set upon, and in 

 good part finished, before Midsummer ; but not completed 

 till near Christmas after, by reason that I returned to Derby 

 about Michaelmas. 



