Page:Dictionary of National Biography volume 27.djvu/291

 ; and he planned in 1691 Alderman Aske's Hospital at Hoxton.

Hooke's astronomical observations showed characteristic acuteness, originality, and inconsequence. He was the first to infer the rotation of Jupiter from the movement of a spot noted on 9 May 1664 (Phil. Trans. i. 3, 245), but left it to Cassini to determine its period. His drawings of Mars on 12 March 1666 (ib. p. 239) served Proctor, after more than two centuries, to fix that planet's exact rate of rotation. The fifth star in the Orion trapezium, rediscovered by Struve in 1826, was casually noted by him on 7 Sept. 1664 (Micrographia, p. 242; Memoirs Royal Astronomical Society, iii. 189). His observations of the comet of 1664 were communicated to the Royal Society on 1 Aug. 1666; and he made in 1669 the earliest attempt at the telescopic determination of the parallax of a fixed star. Observing γ Draconis for the purpose from July to October with a 36-foot telescope pointed through an aperture in the roof of Gresham College, he perceived displacements intimating (as he thought) a parallax of 25″ to 30″, but desisted from further inquiry. His illusory result led to Bradley's discovery of aberration. These experiments formed the subject of Hooke's Cutlerian lectures in 1670, published in 1674 as ‘An Attempt to Prove the Motion of the Earth by Observations.’ The first observation of a star by daylight was recorded in this little work (p. 27).

Hooke, perhaps unaware that Grimaldi had anticipated him, described the phenomena of the diffraction of light in two papers in 1672 and 1675. He was a member of the committee of the Royal Society, to which Newton's communication on the different refrangibilities of light was referred in January 1672, and on 15 Feb. imparted his grounds of objection to it (, Hist. Royal Society, iii. 10). Newton made an elaborate reply (Newtoni Opera, iv. 322), but his ‘Discourse’ on colour on 9 and 16 Dec. 1675 was met by Hooke's declaration that ‘the main of it was contained in the “Micrographia”’ (, Hist. Royal Society, iii. 269). Newton vindicated his originality (ib. p. 278), but a conciliatory private letter from Hooke evoked a reply acknowledging important obligations (, Life of Newton, i. 140).

In a simultaneous controversy with Hevelius, Hooke prejudiced a good cause by bad manners. Hevelius having ignored his recommendation of telescopic sights, he devoted several Cutlerian lectures to unfriendly comments on that ‘curious and pompous book,’ the ‘Machina Cœlestis.’ Hooke's acrid, though just, arguments were collected as ‘Animadversions on the First Part of the “Machina Cœlestis”’ (1674), in which he inserted descriptions of a ‘water-level’ (p. 61), and of a mode of giving clockwork motion to a parallactic instrument (p. 68).

There is no doubt of Hooke's priority in the application of a spiral spring to regulate the balance of watches; but here again his peevish temper brought him discredit. The invention, arrived at about 1658, was designed to solve the problem of longitudes, and Boyle and Brouncker endeavoured to secure him a patent, but he declined their terms, and concealed the improvement until Huygens rediscovered it in 1675. He then caused some of his ‘new watches’ to be constructed by Tompion (one of which was presented to Charles II), and published the principle involved in them of the isochronism of springs in the maxim ‘ut tensio, sic vis,’ appended in cryptographic form to ‘A Description of Helioscopes’ (1676). A quarrel with Oldenburg on the subject culminated in Hooke's accusation of him as ‘a trafficker in intelligence,’ an expression which the Royal Society obliged him to withdraw. It was contained in a postscript to his ‘Lampas, or a Description of some Mechanical Improvements of Lamps and Water-poises’ (1677).

Hooke acted as secretary to the Royal Society after Oldenburg's death, from 25 Oct. 1677 to 30 Nov. 1682, and edited seven numbers of ‘Philosophical Collections,’ substituted by him for the ‘Transactions.’ He declined the post of librarian to the Royal Society in 1679. His ‘Lectures and Collections’ (1678) included ‘Cometa,’ dealing chiefly with the great comet of 1677, and ‘Microscopium.’ His ‘Lectures de Potentiâ restitutiva’ (1678) are designated by Professor Tait (Properties of Matter, p. 194) as ‘a very curious pamphlet containing some remarkably close anticipations of modern theories.’ He expounded in it the true theory of elasticity, and (virtually) the kinetic hypothesis of gases (p. 15). His ‘Lectiones Cutlerianæ’ (1679) were a reissue, under one cover, of the discourses already separately published.

Hooke divined before Newton the true doctrine of universal gravitation, but wanted the mathematical ability to demonstrate it. The mutual attraction of the heavenly bodies was no secret to him, and he foresaw in 1670 that ‘the true understanding of this principle will be the true perfection of astronomy’ (Attempt to Prove the Motion of the Earth, p. 28). But his promise to ‘explain a system of the world answering in all things to the common rules of mechanical motions’ remained unfulfilled. He, however, stated the