��Essay on
��had prepared an instrument, which might be called an epitome or miniature of the terraqueous globe, shewing, with the assist ance of tables constructed by himself, the variations of the magnetic needle, and ascertaining the longitude for the safety of navigation z . It appears that this scheme had been referred to Sir Isaac Newton 2 ; but that great philosopher excusing himself on account of his advanced age, all applications were useless till 1751, when the subject was referred, by order of Lord Anson 3 , to Dr. Bradley, the celebrated professor of Astronomy 4 . His report was unfavourable, though it allows that a considerable progress had been made. Dr. Williams, after all his labour and expence, died in a short time after, a melancholy instance of un rewarded merit 5 . His daughter possessed uncommon talents,
��1 ' It was no new thing then when Columbus, as he sailed westward, marked the variation [of the needle] proceeding from the north-east more and more westerly; but it was a revelation when he came to a posi tion where the magnetic north and the north star stood in conjunction, as they did on this I3th of Sep tember, 1492. As he still moved westerly the magnetic line was found to move farther and farther away from the pole, as it had before the 1 3th approached it. To an observer of Columbus' s quick perceptions, there was a ready guess to possess his mind. This inference was that this line of no variation was a meri dian line, and that divergences from it east and west might have a regu larity which would be found to fur nish a method of ascertaining longi tude far easier and surer than tables or water-clocks.' Justin Winsor's Christopher Columbus, 1891, p. 200.
' According to the Gentleman's Magazine, p. 1042, in 1729; but Newton died in 1727.
3 First Commissioner of the Ad miralty ; ante, p. 195.
4 James Bradley, Savilian Profes
��sor of Astronomy at Oxford, and third Astronomer Royal.
5 His merit was not great, as Bradley reported that in some cases the difference between his tables and the best observations amounted to ten, fifteen, or twenty degrees ! Gentleman's Magazine, 1787, p. 1042.
Johnson, no doubt, had him in mind in the Rambler, No. 67, when in the Garden of Hope he placed one ' who was on the point of dis covering the longitude.' Addison, nearly forty years earlier, in a letter from a member of the Tall Club, said : ' I must add, to the honour of our Club, that it is one of our society who is now finding out the longitude.' The Guardian, No. 108.
Williams had first taken orders, and later on 'was a surgeon, phy sician, and projector.' Some of his projects are given in the Gentleman's Magazine, 1787, p. 1157. He was admitted to the Charter-House, but he was expelled in 1749, at the age of seventy-eight, in consequence of attacks on the management of that Institution. In a letter to General Oglethorpe he describes how 'this
and,
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