KEILL (Dr. John)

, an eminent mathematician and philosopher, was born at Edinburgh in 1671, and studied in the university of that city. His genius leading him to the mathematics, he made a great progress under David Gregory the professor there, who was one of the first that had embraced and publicly taught the Newtonian philosophy. In 1694 he followed his tutor to Oxford, where, being admitted of Baliol College, he obtained one of the Scotch exhibitions in that college. It is said he was the first who taught Newton's principles by the experiments on which they are founded: and this it seems he did by an apparatus of instruments of his own providing; by which means he acquired a great reputation in the university. The first public specimen he gave of his skill in mathematical and philosophical knowledge, was his Examination of Dr. Burnet's Theory of the Earth; with Remarks on Mr. Whiston's New Theory; which appeared in 1698. These theories were defended by their respective authors; which drew from him, in 1699, An Examination of the Reflections on the Theory of the Earth, together with A Defence of the Remarks on Mr. Whiston's New Theory. Dr. Burnet was a man of great humanity, moderation, and candour; and it was therefore supposed that Keill had treated him too roughly, considering the great disparity of years between them. Keill however left the doctor in possession of that which has since been thought the great characteristic and excellence of his work; and though he disclaimed him as a philosopher, yet allowed him to be a man of a fine imagination. “Perhaps, says he, many of his readers will be sorry to be undeceived about his theory; for, as I believe never any book was fuller of mistakes and errors in philosophy, so none ever abounded with more beautiful scenes and surprising images of nature. But I write only to those who might expect to find a true philosophy in it: they who read it as an ingenious romance, will still be pleased with their entertainment.”

The year following, Dr. Millington, Sedleian professor of natural philosophy in Oxford, who had been appointed physician to king William, substituted Keill as his deputy, to read the lectures in the public school. This office he discharged with great reputation; and, the term of enjoying the Scotch exhibition at Baliolcollege now expiring, he accepted an invitation from Dr. Aldrich, dean of Christ-church, to reside there.

In 1701, he published his celebrated treatise, intitled, Introductio ad Veram Physicam, which is supposed to be the best and most ufeful of all his performances. The first edition of this book contained only fourteen lectures; but to the second, in 1705, he added two more. This work was deservedly esteemed, both at home and abroad, as the best introduction to the Principia, or the new mechanical philosophy, and was reprinted in different places; also a new edition in English was printed at London in 1736, at the instance of M. Maupertuis, who was then in England.

Being made Fellow of the Royal Society, he published, in the Philos. Trans. 1708, a paper on the Laws of Attraction, and its physical principles: and being offended at a passage in the Acta Eruditorum of Leipsic, where Newton's claim to the first invention of the me-| thod of Fluxions was called in question, he warmly vindicated that claim against Leibnitz. In 1709 he went to New-England as treasurer of the Palatines; and soon after his return in 1710, he was chosen Savilian professor of astronomy at Oxford. In 1711, being attacked by Leibnitz, he entered the lists with that mathematician, in the dispute concerning the invention of Fluxions. Leibnitz wrote a letter to Dr. Hans Sloane, then secretary to the Royal Society, requiring Keill, in effect, to make him satisfaction for the injury he had done him in his paper relating to the passage in the Acta Eruditorum: he protested, that he was far from assuming to himself Newton's method of Fluxions; and therefore desired that Keill might be obliged to retract his false assertion. On the other hand, Keill desired that he might be permitted to justify what he had asserted. He made his defence to the approbation of Newton, and other members of the Society. A copy of this was sent to Leibnitz; who, in a second letter, remonstrated still more loudly against Keill's want of candour and sincerity; adding, that it was not sit for one of his age and experience to engage in a dispute with an upstart, who acted without any authority from Newton, and desiring that the Royal Society would enjoin him silence. Upon this, a special committee was appointed; who, after examining the facts, concluded their report with “reckoning Mr. Newton the inventor of Fluxions; and that Mr. Keill, in asserting the same, had been no ways injurious to Mr. Leibnitz.” The whole proceedings upon this matter may be seen in Collins's Commercium Epistolicum, with many valuable papers of Newton, Leibnitz, Gregory, and other mathematicians. In the mean time Keill behaved himself with great firmness and spirit; which he also shewed afterwards in a Latin epiftle, written in 1720, to Bernoulli, mathematical professor at Basil, on account of the same usage shewn to Newton: in the title-page of which he put the arms of Scotland, viz, a Thistle, with this motto, Nemo me impune lacessit.

About the year 1711, several objections being urged against Newton's philosophy, in support of Des Cartes's notions of a plenum, Keill published a paper in the Philos. Trans. on the Rarity of Matter, and the Tenuity of its Composition. But while he was engaged in this dispute, queen Anne was pleased to appoint him her Decipherer; and he continued in that place under king George the First till the year 1716. The university of Oxford conferred on him the degree of M. D. in 1713; and, two years after, he published an edition of Commandine's Euclid, with additions of his own. In 1718 he published his Introductio ad Veram Astronomiam: which was afterwards, at the request of the duchess of Chandos, translated by himself into English; and, with several emendations, published in 1721, under the title of An Introduction to True Astronomy, &c. This was his last gift to the public; being this summer seized with a violent fever, which terminated his life Sept. 1, in the 50th year of his age.

His papers in the Philos. Trans. above alluded to, are contained in volumes 26 and 29.

Keill (Dr. James), an eminent physician and philosopher, and younger brother of Dr. John Keill above mentioned, was also born in Scotland, in 1673. Having travelled abroad, on his return he read lectures on Anatomy with great applause in the universities of Oxford and Cambridge, by the latter of which he had the degree of M. D. conferred upon him. In 1703 he settled at Northampton as a physician, where he died of a cancer in the mouth in 1719. His publications are

1. An English translation of Lemery's Chemislry.

2. On Animal Secretion, the quantity of Blood in the Human Body, and on Muscular Motion.

3. A treatise on Anatomy.

4. Several pieces in the Philos. Trans. volumes 25 and 30.