Royal Society on 21 April 1763. Immediately on his appointment in 1772 as the first Radcliffe observer, he laid the foundation-stone of the present observatory, which was not completed until 1794. Its equipment (the finest of that time) included two quadrants and a transit-instrument, each of eight feet, a zenith sector, an equatoreal, and a Dollond's achromatic refractor, to which a Newtonian reflector by Sir William Herschel was added later. The outlay upon buildings and instruments amounted to 28,000l. A regular series of transit-observations was made there as long as Hornsby lived. After his appointment, however, in 1782 to the Sedleian professorship, much of his attention was taken up with his excellent series of lectures on experimental philosophy; and he became Radcliffe librarian as well in 1783. Hornsby died at Oxford on 11 April 1810, aged 76. His two sons, Thomas (1766–1832) and George (1781–1837), both graduated from Christ Church, Oxford. The former was vicar of Ravensthorpe, Northamptonshire, from 1797 till death; the latter vicar of Turkdean, Gloucestershire, from 1809 till death.
Hornsby observed the transit of Venus of 6 June 1761 at Shirburn Castle, that of 3 June 1769 at Oxford, and deduced from both a solar parallax (8″.78) almost identical with the best modern results. He took an active share in the scientific pursuits of the Earl of Macclesfield. Five papers by him were read before the Royal Society, viz.: 1. ‘A Discourse on the Parallax of the Sun’ (Phil. Trans. liii. 467). 2. ‘On the Transit of Venus in 1769’ (ib. lv. 326). 3. ‘An Account of the Observations of the Transit of Venus and of the Eclipse of the Sun, made at Shirburn Castle and at Oxford’ (ib. lix. 172). 4. ‘The Quantity of the Sun's Parallax as deduced from the Observations of the Transit of Venus on 3 June 1769’ (ib. lxi. 574). 5. ‘An Inquiry into the Quantity and Direction of the Motion of Arcturus’ (ib. lxiii. 93). He remarked in 1798 the common proper motion of the stars of Castor, but failed to infer their physical connection (Grant, History of Astronomy, p. 559). The first volume of Bradley's ‘Astronomical Observations’ was edited by him for the Clarendon Press in 1798. He had undertaken the task more than twenty years previously, and the delay, for which he was acrimoniously censured, was due to his ill-health.
[Foster's Alumni Oxonienses, ii. 693; Honours Register (1883), pp. 89, 123, 491; Gent. Mag. 1810, pt. i. p. 494; The Georgian Era, iii. 490 (1834); Nichols's Lit. Anecd. iii. 707, viii. 232, 260; Nichols's Illustr. of Lit. iv. 516, 787; André et Rayet's L'Astronomie Pratique, i. 53; Lalande's Bibl. Astronomique, p. 484; Poggendorff's Biog. Lit. Handwörterbuch; Mädler's Gesch. der Astronomie, i. 465, 470, 472, 489; Bradley's Misc. Works, Preface (Rigaud); Watt's Bibl. Brit.]
HORROCKS, JEREMIAH (1617?–1641), astronomer, was born at Toxteth Park, near Liverpool, in a house of which the site is now occupied by the Otterspool railway station. The traditional date is 1619, but 1617 is more likely correct. His father, a small farmer, named, it is supposed, William Horrocks, was a member of a respectable puritan family, originally from Horrocks Fold, near Rumworth in Lancashire. Early grounded in the classics by a country schoolmaster, Horrocks was his own instructor in science, and is stated to have been already ‘a very curious astronomer’ at his entry as sizar in Emmanuel College, Cambridge, on 18 May 1632. The university proved of little service to him; yet without mathematical instruction or the stimulus of sympathy, he determined ‘that the tediousness of study should be overcome by industry, my poverty by patience, and that instead of a master I would use astronomical books.’ In the library of Trinity College, Cambridge, is preserved a copy of Lansberg's ‘Tables,’ purchased by him in 1635, and containing a list in his handwriting of works on astronomy (Companion to British Almanac, 1837, p. 28). He left Cambridge without a degree after three years' residence, summoned home probably by family necessities. His first observation was made at Toxteth on 7 June 1635, and through the medium of Christopher Townley he opened a year later a correspondence with William Crabtree [q. v.] From him he learned the untrustworthiness of Lansberg's ‘Tables,’ and threw himself zealously into the study of Kepler's works. Instantly approving the Keplerian hypotheses, he saw that the numbers used required corrections, which he set himself to supply from his own observations, carried on in the midst of harassing daily occupations with instruments of the rudest kind. In May 1638 he bought a telescope for half-a-crown, and observed with it the partial solar eclipse of 22 May 1639 (Opera Posthuma, pp. 387–9). In June 1639 he visited Crabtree at Broughton, near Manchester, and shortly after acquired Galileo's ‘Astronomical Dialogues.’ Some of Horrocks's and Crabtree's improvements were communicated to Dr. Samuel Foster [q. v.] of Gresham College.
Ordained in 1639 to the curacy of Hoole, a poor hamlet eight miles south-west of Preston, he was obliged to eke out his annual stipend of 40l. by tuition or some similar drudgery.
