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“Sir,

March 10th, 1712–13. “I received what you wrote to me in Sir Isaac's letter. I will set about the index in a day or two. As for the preface, I should be glad to know from Sir Isaac with what view he thinks proper to have it written. You know the book has been received abroad with some disadvantage, and the cause of it may be easily guessed at. The Commercium Epistolicum, lately published by order of the Royal Society, gives such indubitable proofs of Mr. Leibnitz's want of candour, that I shall not scruple in the least to speak out the full truth of the matter, if it be thought convenient. There are some pieces of his looking this way which deserve a censure, as his Tentamen de motuum cælestium causis. If Sir Isaac is willing that something of this nature may be done, I should be glad if, while I am making the index, he would consider of it, and put down a few notes of what he thinks most material to be insisted on. This I say upon supposition that I write the preface myself. But I think it will be much more advisable that you, or he, or both of you should write it while you are in town. You may depend upon it I will own it, and defend it as well as I can, if hereafter there be occasion.-I am sir, &c."

We are not acquainted with the instructions which were given to Mr. Cotes in consequence of this application; but it appears from the preface itself, which contains a long and able summary of the Newtonian philosophy, that Sir Isaac had prohibited any personal reference to the conduct of Leibnitz.

The general preface is dated 12th May, 1713, and in a subsidiary preface of only a few lines, dated March 28th, 1713, Sir Isaac mentions the leading alterations which had been made in this edition. The determination of the forces by which bodies may revolve in given orbits was simplified and enlarged. The theory of the resistance of fluids was

more accurately investigated, and confirmed by new experiments. The theory of the moon and the precession of the equinoxes were more fully deduced from their principles; and the theory of comets was confirmed by several examples of their orbits more accurately computed.

In the year 1714, several captains and owners of merchant vessels petitioned the House of Commons to consider the propriety of bringing in a bill to reward inventions for promoting the discovery of the longitude at sea. A committee was appointed to investigate the subject, and Mr. Ditton and Mr. Whiston, having thought of a new method of finding the longitude, submitted it to the committee. Four members of the Royal Society, viz. Sir Isaac Newton, Dr. Halley, Mr. Cotes, and Dr. Clarke, were examined on the subject, along with Mr. Ditton and Mr. Whiston. The last three of these philosophers stated their opinions verbally. Mr. Cotes considered the proposed scheme as correct in theory and on shore, and both he and Dr. Halley were of opinion that expensive experiments would be requisite. Newton, when called upon for his opinion, read the following memorandum, which deserves to be recorded.

“For determining the longitude at sea there have been several projects, true in theory, but difficult to execute.

“1. One is by a watch to keep time exactly; but by reason of the motion of the ship, the variation of heat and cold, wet or dry, and the difference of gravity in different latitudes, such a watch hath not yet been made.

“2. Another is by the eclipses of Jupiter's satellites; but by reason of the length of telescopes requisite to observe them, and the motion of a ship at sea, those eclipses cannot yet be there observed.

“3. A third is by the place of the moon; but her theory is not yet exact enough for that purpose ; it

is exact enough to determine the longitude within two or three degrees, but not within a degree.

“ 4. A fourth is Mr. Ditton's project, and this is rather for keeping an account of the longitude at sea than for finding it, if at any time it should be lost, as it may easily be in cloudy weather. How far this is practicable, and with what charge, they that are skilled in sea affairs are best able to judge. In sailing by this method, whenever they are to pass over very deep seas, they must sail due east or west; they must first sail into the latitude of the next place to which they are going beyond it, and then keep due east or west till they come at that place. In the first three ways there must be a watch regulated by a spring, and rectified every visible sunrise and sunset, to tell the hour of the day or night. In the fourth way such a watch is not necessary. In the first way there must be two watches, this and the other above mentioned. In any of the first three ways, it may be of some service to find the longitude within a degree, and of much more service to find it within forty minutes, or half a degree if it may, and the success may deserve rewards accordingly. In the fourth way, it is easier to enable seamen to know their distance and bearing from the shore 40, 60, or 80 miles off, than to cross the seas; and some part of the reward may be given when the first is performed on the coast of Great Britain for the safety of ships coming home; and the rest when seamen shall be enabled to sail to an assigned remote harbour without losing their longitude if it may be."

The committee brought up their report on the 11th June, and recommended that a bill should be introduced into parliament for the purpose of rewarding inventions or discoveries connected with the determination of the longitude. The bill passed the House of Commons on the 3d July, and was agreed to by the Lords on the 8th of the same month. *

* Journals of the House of Commons, vol. xvii. p. 677, 716.

In giving an account of this transaction,* Mr. Whiston states, that nobody understood Sir Isaac's paper, and that after sitting down he obstinately kept silence, though he was much pressed to explain himself more distinctly. At last, seeing that the scheme was likely to be rejected, Whiston ventured to say that Sir Isaac did not wish to explain more through fear of compromising himself, but that he really approved of the plan. Sir Isaac, he goes on to say, repeated word for word what Whiston had said. This is the part of Mr. Newton's conduct which M. Biot has described as puerile, and “tending to confirm the fact of the aberration of his intellect in 1693.” Before we can admit such a censure we must be satisfied with the correctness of Whiston's statement. Newton's paper is perfectly intelligible, and we may easily understand how he might have approved of Mr. Ditton's plan as ingenious and practicable under particular circumstances, though he did not think it of that paramount importance which would have authorized the House of Commons to distinguish it by a parliamentary reward. The conflict between public duty and a disposition to promote the interests of Mr. Whiston and Mr. Ditton was no doubt the cause of that embarrassment of manner which the former of these mathematicians has so unkindly brought before the public.

* Whiston's “ Longitude Discovered." Lond 1738.

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CHAPTER XV.

Respect in which Nerrton was held at the Court of George I.-The Prin

cess of Wales delighted with his Conversation--Leibnitz endeavours to prejudice the Princess against Sir Isaac and Locke-Controversy occasioned by his Conduct- The Princess obtains a Manuscript Abstract of his System of Chronology-The Abbé Conti is, at her request, allowed to take a Copy of it on the promise of Secresy-He prints it surreptitiously in French, accompanied with a Refutation by M. Freret

Sir Isaac's Defence of his System-Father Souciet attacks it-and is answered by Dr. Halley-Sir Isaac's larger Work on Chronology published after his Death-Opinions respecting it-Sir Isaac's Paper on the Form of the most ancient Year.

On the accession of George I. to the British throne in 1714, Sir Isaac Newton became an object of interest at court. His high situation under government, his splendid reputation, his spotless character, and, above all, his unaffected piety attracted the attention of the Princess of Wales, afterward queen-consort to George II. This lady, who possessed a highly cultivated mind, derived the greatest pleasure from conversing with Newton and corresponding with Leibnitz. In all her difficulties, she received from Sir Isaac that information and assistance which she had elsewhere sought in vain, and she was often heard to declare in public that she thought herself fortunate in living at a time which enabled her to enjoy the conversation of so great a genius. But while Newton was thus esteemed by the house of Hanover, Leibnitz, his great rival, endeavoured to weaken and undermine his influence. In his correspondence with the princess, he represented the Newtonian philosophy, not only as physically false, but as injurious to the interests of religion. He asserted that natural religion was rapidly declining in England, and he supported this position by referring to the works of Locke, and to

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