1835.] First Astronomer- Royal. 317 



screwed the edge of the limb ; prepared the index ; fas- 

 tened the arc on the wall ; planed it anew, which cost three 

 months labour, and then it was rectified, divided and en- 

 graved by his hand. It was finished in October, 1689, after 

 fourteen months work, and a personal expense to Flam- 

 steed of £100. He found his observations greatly facili- 

 tated by the possession of this arc, as it required only one 

 assistant; whereas, with the sextant, two were scarcely 

 sufficient. With the sextant, in the open air, he could not 

 see some small stars of the 6th light ; while, with the arc, 

 through a slit 1| foot wide, he could see stars of the 7th 

 light plainly with the naked eye. His synopses of the places 

 of the moon were communicated to Newton. 



In January 1694, having collected all his observations of 

 the pole star into one synopsis, he was surprised to find 

 that its distances from the pole were always bigger in 

 March, April, July, August, and September, than in De- 

 cember. He attributed it to the parallax of the earth's 

 orb being sensible in the pole star. While investigating 

 the inequalities of the earth's orbit, and the place of the 

 aphelion, he determined the right ascensions of about forty 

 fixed stars. 



In 1676 Sir Jonas Moore gave him the sextant, some 

 books and glasses, with charge to dispose of them by his 

 will. All the other instruments and tables were provided 

 at his own expense. 



In December 12th, 1680, he first observed .the great 

 comet, and noticed it till February 5, 1680-1. In 1681 he 

 imparted his observations on the comet to Sir Isaac Newton, 

 as a friend ; and in 1685, or 86, gave him the diameters of 

 the planets in all portions of the earth, and then in their 

 orbits, and got them back again with much difliculty, after 

 two years detention. Newton disputed against the comets of 

 November and December being the same, in two long letters 

 in February and March 1681 ; but in 1685 owned they 

 might be as Flamsteed asserted, and " slightly men- 

 tioned me as disputing for their being the same in the 4th 

 book of his Principia : Whereas, I affirmed it and himself 

 disputed against it." 1688, the Principia published. Little 

 notice taken of the Queen's Observatory. 1687. He built 

 a strong mural arc for £120, by which the places of 3000 



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