1835.] First Astronomer-Royal. 415 



obliged him to construct one of his own, of 50 inches radius, 

 and capable of greater precision. 



Besides this, he procured at his own expense, tubes and 

 telescope glasses of 16 and 8 feet long, to which he applied 

 his micrometer for observing the moon's transits, by and 

 over fixed stars. A large wall quadrant was at this time 

 made by Mr. Hook, but so clumsily, that it was of no use. 

 This vexed him, but he fortunately found a way of fixing 

 his sextant in the meridian, so as to take the greatest 

 heights of some stars that passed near the vertex, and 

 thereby ascertaining the error of the instrument, and next 

 took the greatest and least heights of the pole-stars. Thus, 

 in December, 1676, he found the simple latitude of the 

 Observatory, 51° 28' 50", but correct by refraction, 51° 

 28' 10". 



In 1678, although ill, he made many observations to cor- 

 rect the earth's motion, (without the true knowledge either 

 of the obliquity of the ecliptic, or the exact places of the 

 fixed stars) by determining " the Sun's distances from Ve- 

 nus, hers from fixed stars and their meridional distances 

 from the vertex." The tables he had made from Tycho and 

 Cassini's observations, gave the greatest equation of her 

 orbit 8' less than Kepler's. To settle the question, in 1679, 

 he took the longitude of the bright star of Aries, from 

 Tycho's catalogue, and reduced it to that year, by allowing 

 50" for the annual precession ; the latitude vras corrected 

 by the meridional height taken with the sextant. The 

 places of other stars required were corrected from these 

 data. The tables were finished in the Spring. On the 27th 

 August, 1679, Sir Jonas Moore died at Godalming, in Surrey, 

 with whom fell all Flamsteed's hopes for having any allow- 

 ance granted for increasing the number of his instruments. 

 Sir Jonas left a book in the press for the use of Christ 

 Church Hospital, which was finished by Perkins and Flam- 

 steed ; the former of whom wrote in it the Navigation, and 

 the latter the Doctrine of the Sphere. This labour being over, 

 in 1681 he prosecuted his observations for rectifying the 

 places of the fixed stars and planets motions, but he found 

 that he could not determine the true longitude of the equi- 

 noctial points, from the fixed stars, without a fixed instru- 

 ment for determining their distances from the pole of the 



