Syzygys, so accurately by Calculation, that the Difference between that and her true Place in the Heavens, shall scarce be above two minutes in her Syzygys, or above three in her Quadratures, and is usually so small, that it may well enough be reckon'd only as a Defect in the Observation. And this Mr. Newton experienced, by comparing it with very many Places of the Moon, observ'd by Mr. Flamsteed, and communicated to him.
The Royal Observatory at Greenwich, is to the West of the Meridian of Paris, 2 degrees, 19 minutes. Of Uraniburgh, 12 degrees, 51 minutes, 30 seconds. And of Gedanum, 18 degrees, 48 minutes.
The mean Motions of the Sun and Moon, accounted from the Vernal Æquinox at the Meridian of Greenwich, I make to be as followeth.
The last Day of December 1680, at Noon (Old Stile) the mean Motion of the Sun was 9 Signs, 20 degrees, 34 minutes, 46 seconds. Of the Sun's Apogæum, was 3 S.