was now come up to the fitting Members of the Committee, hearing fo fmall a Sum named, expreffed fome Indignation at it; and faid, that "fince fo much larger Sums were often given for "much smaller Defigns, he thought it a Shame

that fo noble a one as this should have no more than 500 / allotted for it. Let it, faid he, be ❝ 2000 l." Which Propofal was complied with, without any Hefitation; and 2000. is the Sum allotted for Trials accordingly in that Act of Parliament; which Act or Bill was first drawn up at General Stanhope's, by the General himself, by Mr. Walpole, Dr. Clarke, and Mr. Whifton; and being afterwards put in Form by a Lawyer, paffed both Houses Nemine Contradicente.*

There are yet two Deficiencies in this Bill, which, Mr. Wbifton perfuades himself, are owing merely to these two Claufes not having been thought of and propofed at the Time of its being drawn up, viz. One, to enable the Commiffioners to apply Part of the 2000 7. allotted for Trials, to the fettling the Longitudes and Latitudes of the Capes and Ports along the Coafts; without which all Methods for discovering the Longitude at Sea are in a man. ner ufelefs: The other, for giving fome Reward for any confiderable Improvements in finding even the Latitude, which, hitherto, is the main thing our Navigators are forced to have Recourfe to in their Diftreffes at Sea.

It is intitled, An Act for providing a publick Reward for fuch Perfon or Perfons as fall discover the Longitude at Sea; wherein the Reward is 10,000 7. if it extend only to one Degree of a great Circle, or 60 Geographical Miles; 15,000/ if to 40, and 20,000 7. it to 30 fuch Miles: With this Provifo, that if any fuch Method extend no farther than to 80 Miles adjoining to the Coafts, the Propofer fhall have no more than one Half of fuch Rewards refpectively: As alfo with another Provife, that any leffer Difcovery of the fame Longitude may have a proportionably leffer Reward. But all according to the Determination of the Commiffioners therein named.

As

As for the latter Omiffion, Mr. Whifton here takes notice of it, because not very long after the paffing of the aforefaid Act, Mr. Rowe procured a Meeting of the Commiffioners for the Longitude, in order to defire fome Reward for an Improvement he pretended to have made in the Discovery of the Latitude. Sir Ifaac Newton and Dr. Halley were there, as well as the Lord Trevor and other Commiffioners. And altho' this Application appeared evidently beyond their Power, yet did he make his Pretenfions fo effectual at the Board of Admiralty, that a Bill was brought in by Admiral Jennings into the Houfe of Commons, 1720, for a Reward in general to Improvements in Navigation, which it was fuppofed would have enabled the Commiffioners to reward Mr. Rowe, but it was rejected at the last Reading. However, he was fo far favoured by the Admiral and the Admiralty, that 500 7. was allotted him out of the contingent Money for the Navy: As Dr. Halley had formerly had 200 l. out of the fame contingent Money allotted him by the Lord Pembroke, when he was Lord High Admiral, for his most useful Survey of the British Channel: Altho' Mr. Wbifton questions whether Mr. Rowe's Propofal for finding the Latitude ever came to be practised at Sea fince that Time.

Thus much relating to Mr. Whifton's firft Attempt for discovering the Longitude, by Signals; which Affair he tranfacted in Concert with Mr. Ditton. And tho' it has not been followed either here or abroad, for that Purpofe; yet it has been applied, in fome Measure, for ftating the Geography of certain Places upon Land, with good Succefs.

A fecond Method for difcovering the Longitude at Sea, in which Mr. Whilton concerned himself, was this. About the Middle of November 1718, one Eberhard, a German, came to him with a Pre

tence

tence to a Method for Discovering the Longitude by a Magnetic Dipping-Needle. But as the other Mathematicians and Virtuofo's could make nothing of Mr. Eberhard's Pretenfions, which depended on the Dip being in or parallel to the Equator, and the magnetic Power exerting itfelf: Eaft and West, contrary to all Experience; fo did. Mr. Whiston, after fome Time, find it to be wholly groundless. However, the Confideration of this Dipping-Needle, an Inftrument he had hardly ever feen, or indeed heard of to any Purpose before, occafioned many Thoughts and Experiments of his own, to fee whe'ther this Power of a magnetic Needle, when it, vibrates in a vertical Plane, and defcends beneath the Horizon, might not, by fome proper Contrivance, be made ufe of at leaft for the Difcovery of the Latitude, if not alfo for that of the Longitude, at Sea, as well as at Land. In the Profecution of which Inquiries he went feveral hundred Miles in Company with Mr. Barker, and made a great number of Obfervations, with different Loadftones, and different Dipping Needles, in different Counties of this Land. He alfo procured many others to be made in several remote Parts of the Earth and Sea, till the Hopes became tolerable, that both the Longitude and Latitude would at length be difcovered by fuch Dipping-Needles, if they were fufficiently large, and exact, and. well hung in the Ship. But all became abortive; and three Circumftances concur'd to extinguifh almost all his Hopes of difcovering the Latitude, and entirely all his Hopes of difcovering the Longitude by this Inftrument. The firft was the Weaknefs of the magnetic Power: The fecond was the Concuffion of the Ship; which he found it prodigiously hard to avoid, fo much as the Nicety of thefe Experiments required': The third and principal was an hitherto unknown Irregularity in the Motions of all Magnetic Needles, both Horizontal

rizontal and dipping, difcovered, upon this Occafion, by Mr. George Graham, and foon confirmed by Mr. Wbifton's own Obfervations: Whereby they, within about the Compafs of a Degree, vary uncertainly backward and forward, even fometimes in a few Hours Time, without the Dependance on any visible Cause whatsoever.

One Thing of fome Confequence Mr. Whifton here adds, as not improperly coming in; which is this. Dr. Halley and He had been some time debating, whether the Earth's Magnet or Magnets, had only one, or not rather two Northern Poles: Mr. Whiston maintaining there was but one internal Magnet, and that it had but one Northern Pole; while the Doctor afferted two fuch Poles, and determined the fecond Pole to be about Hudson's Bay. Mr. Whiston judged this Debate would best be ended by fending a Dipping-Needle to Hudfon's Bay; which he did, A. D. 1723. The Effects of this he heard nothing of till the Year 1739, when Capt. Middleton, who went Mate of that Ship in which the Dipping-Needle was fent, being returned to England, affured him that he had himfelf tried the Experiment 79 Degrees Weft of London, at Cape Diggs, in Hudfon's Streights; and found that the Needle ftood strongly perpendicular at that Place. Which certainly implies the Being of fuch a magnetic Pole there as Dr. Halley fuppofed. And indeed fuch a Pole was known to be thereabout earlier than the Days of Dr. Halley: Mr. Barker having fince fhewed it Mr. Whifton, noted by a Circle, and the Words Polus Magnetis, on the Delineation of that Part of the Globe, about the very Place affigned for it by Dr. Halley, in Gerrard Mercator's Edition of Ptolemy's Maps in the Year 1574.

However, his Difappointment in thefe Attempts did not fo far difcourage Mr. Whiffon, but that he afterwards joined his Endeavours with Mr. Hafelden,

when

61 when a third Propofal was thought of, viz. "That for improving Dr. Halley's Method of finding the Longitude by the Appulfes of the Moon to fixed Stars. This had been propofed about two Centuries ago by Apian, an Aftronomer; and has been long and earneftly pursued, and with much greater Hopes of Succefs by Mr. Flamfteed and Dr. Halley; efpecially by the latter. Its Nature and Truth in Theory is well known.

Now Mr. Hafelden endeavoured to render this. Method much more useful, by multiplying the Occafions of knowing the Moon's Place, and difcover, ing the fame; not only at its Appulfe to fixed Stars, as in Mr. Flamfteed's and Dr. Halley's Way; but by the fmall Interval of its Rifing and Setting, from thofe of a known fixed Star, to be measured by a Pocket Watch: And by the Help of Trigonometrical Calculations determining the unknown Place of the Moon, by the known Place of the fixed Star. To this Propofal Mr. Whifton made certain Improvements, and took fome Pains in conquering the Difficulties that occur'd therein. But when, after all his and Mr. Hafelden's Pains, it appeared, that the very Points of Time of the Rifing or Setting of even the larger fixed Stars were hardly vifible at Sea; that the Inequalities in the Moon's Motion were not yet brought to exactness ; and that the Calculations neceffary in this way were, for all different Latitudes, almost innumerable; they found Caufe to drop the further Profecution of this Method. So far only did Mr. Wbifton follow this Intimation, as to try how near the Interval of the Rifing or Setting of two fixed Stars, of the firft Magnitude, thus taken by a Watch, would difcover the Latitude itfelf? which he found it would do to great Exactnefs. But then, as there are fo many eafier Ways of finding that Latitude, and very few Stars can be feen directly upon the Hori

zon,