L E T T E R
of 15 September 1689
from J O H N A U B R E Y (1626–1697)
to A N T H O N Y W O O D (1632–1695)
enclosing a communication from
R O B E R T H O O K E (1635–1703)
[ Hooke’s MS. and corrections to Aubrey’s draft
are marked below with an orange background. ]
September 15, 1689.
Mr. Wood!
Mr. Robert Hooke, R.S.S. did in anno 1670, write a discourse, called, “An Attempt to prove the motion of the Earth,” which he then read to the Royal Society; but printed it in the beginning of the yeare 1674, a strena to Sir John Cutler to whom it is dedicated, wherein he haz delivered the theorie of explaining the coelestial motions mechanically; his words are these, pag. 27, 28. viz.:—
In the Attempt to prove the motion of the earth, etc., printed 1674, but read to the Royall Society, 1671: pag. 27, line 31—
“I shall only for the present hint that I have in some of my foregoing observations discovered some new motions even in the Earth it self, which perhaps were not dreamt of before, which I shall hereafter more at large describe, when further tryalls have more fully confirmed and compleated these beginnings. At which time also I shall explaine a systeme of the world, differing in many particulars from any yet known, answering in all things to the common rules of mechanicall motions. This depends upon 3 suppositions; first, that all coelestiall bodys whatsoever have an attractive or gravitating power towards their own centers, whereby they attract not only their own parts, and keep them from flying from them, as we may observe the Earth to doe, but that they doe also attract all the other coelestial bodys that are within the sphere of their activity, and consequently that not only the Sun and the Moon have an influence upon the body and motion of the Earth, and the Earth upon them, but that Mercury also, Venus, Mars, Saturne, and Jupiter, by their attractive powers have a considerable influence upon its motion, as, in the same manner, the corresponding attractive power of the Earth hath a considerable influence upon every one of their motions also. The second supposition is this, that all bodys whatsoever, that are putt into direct and simple motion will soe continue to move forwards in a straight line, till they are by some other effectuall powers deflected and bent into a motion describing a circle, ellipsis, or some other uncompounded curve line. The third supposition is, that these attractive powers are soe much the more powerfull in operating, by how much nearer the body wrought upon is to their own centers. Now what these severall degrees are, I have not yet experimentally verified.”—But these degrees and proportions of the power of attraction in the celestiall bodys and motions, were communicated to Mr. Newton by R. Hooke, in the yeare 1678, by letters, as will Plainely appear both by the coppys of the said letters, and the letters of Mr. Newton in answer to them, which are both in the custody of the said R. H., both which also were read before the Royall Society at their publique meeting, as appears by the Journall book of the said Society.—“But it is a notion which if fully prosecuted, as it ought to be, will mightily assist the astronomer to reduce all the coelestiall motions to a certaine rule, which I doubt will never be done true without it. He that understands the natures of the circular pendulum and circular motion, will easily understand the whole ground of this principle, and will know where to find direction in nature for the true stating thereof. This I only hint at present to such as have ability and opportunity of prosecuting this inquiry, and are not wanting of industry for observing and calculating, wishing heartily such may be found, having my self many other things in hand, which I will first compleat, and therefore cannot soe well attend [to] it. But this I durst promise the undertaker; that he will find all the great motions of the world to be influenced by this principle, and that the true understanding thereof will be the true perfection of Astronomy.”
About 9 or 10 years ago, Mr. Hooke writt to Mr. Isaac Newton, of Trinity College, Cambridge, to make a demonstration of this theory, not telling him, at first, the proportion of the gravity to the distance, nor what was the curv’d line that was thereby made. Mr. Newton, in his answer to the letter, did expresse that he had not known of it; and in his first attempt about it, he calculated the curve by supposing the attraction to be the same at all distances: upon which, Mr. Hooke sent, in his next letter, the whole of his hypothesis, scil. that the gravitation was reciprocall to the square of the distance, which a would make the motion in an ellipsis, in one of whose foci the sun being placed, the aphelion and perihelion of the planet would be opposite to each other in the same line, which is the whole coelestiall theory, concerning which Mr. Newton hath a demonstration, not at all owning he receiv’d the first intimation of it from Mr. Hooke. Likewise Mr. Newton haz in the same booke printed some other theories and experiments of Mr. Hooke’s, as that about the oval figure of the earth and sea: without acknowledgeing from whom he had them, though he had not sent it up with the other parts of his booke till near a month after the theory was read to the Society by Mr. Hooke, when it served to help to answer Dr. Wallis his arguments produced in the Royal Society against it.
Mr. Wood! This is the greatest discovery in nature that ever was since the world’s creation. It never was so much as hinted by any man before. I know you will doe him right. I hope you may read his hand. I wish he had writt plainer, and afforded a little more paper.
Tuus,
J. AUBREY.
Before I leave this towne, I will gett of him a catalogue of what he hath wrote; and as much of his inventions as I can. But they are many hundreds; he believes not fewer than a thousand. ’Tis such a hard matter to get people to doe themselves right.
— Letter postmarked 15 Sept. 1689, from John Aubrey (1626–1697) to Anthony Wood (1632–1695), with MS. amendments and enclosure by Robert Hooke (1635–1703). Words marked with an orange background are Hooke’s autograph, added at the time Hooke made corrections to Aubrey’s draft.
As transcribed and printed by Andrew Clark in “Brief lives,” chiefly of contemporaries, set down by John Aubrey, between the years 1669 & 1696; ed. from the author’s mss. by Andrew Clark ... (Oxford: Clarendon Press, 1898), i: 412–415.
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