Dictionary of National Biography, 1885-1900/Pritchard, Charles

​PRITCHARD, CHARLES (1808–1893), astronomer, was the fourth son of William Pritchard, an enterprising but unsuccessful manufacturer, and was born at Alberbury, Shropshire, on 29 Feb. 1808. His family having removed to Brixton, he entered Merchant Taylors' School as a day-boy in January 1819, and during a year and a half walked to Suffolk Lane, a distance of four miles, every morning before seven. Transferred to John Stock's academy at Poplar, he learned the use of some old astronomical instruments made by James Ferguson (1710–1776) [q. v.], and earned two guineas when fifteen by instructing a would-be colonist in field surveying. His last school was Christ's Hospital, where for a twelvemonth he headed the deputy Grecians. Long early walks here again became part of his life, and he utilised them in learning ​by rote passages from classical authors. Pecuniary difficulties at home, however, compelled his removal; and for two years he worked alone, chiefly at mathematics, attending also some lectures on chemistry. In 1825, when only seventeen, he published an ‘Introduction to Arithmetic,’ and in 1826 was enabled, by the help of friends, to enter St. John's College, Cambridge, whence he graduated as fourth wrangler in 1830. He proceeded M. A. in 1833, having been elected a fellow of his college in March 1832. He had already communicated to the Cambridge Philosophical Society a paper on the ‘Figure of the Earth,’ and he published in 1831 a ‘Treatise on the Theory of Statical Couples,’ which was adopted in the teaching of the university, and reached a second edition in 1837. In 1833 he accepted the head-mastership of a school at Stockwell, newly started in connection with King's College. Dean Bradley, one of his pupils there, described him as ‘a young man, full of fire, enthusiasm, and original ability’ (Nineteenth Century, March 1884). Difficulties, however, with the governing body caused his speedy resignation; and the Clapham grammar school was founded to give him a freer hand in carrying out much-needed educational reforms. Over this establishment he presided with remarkable success from 1834 to 1862. His system of teaching was wide and accommodating, his zeal indefatigable; and pupils were attracted from all parts of the kingdom. Among them were Dean Bradley and Professor Mivart, with the sons of Sir John Herschel, Sir George Airy, Sir William Rowan Hamilton, and Charles Darwin. A banquet given in Pritchard's honour in 1886 by the ‘Old Boys’ of Clapham was a unique tribute to the manner of his rule there. He was moved by it to write a short autobiography, which he circulated among his friends.

On leaving Clapham, Pritchard retired with his family to Freshwater in the Isle of Wight. He had been ordained in 1834, and earnestly desired to devote himself to pastoral duties, but failed to obtain a cure. He nevertheless delivered addresses, generally on the harmony between science and Scripture, at various church congresses, and preached so often before the British Association that he came to be known as its ‘chaplain.’ His discourse at the Nottingham meeting in 1866 suggested to his friend, Sir William Page Wood (afterwards Lord Hatherley), the latter's work on ‘The Continuity of Holy Scripture,’ and led to his own appointment as Hulsean lecturer at Cambridge in 1867. He was, besides, one of the select preachers at Cambridge in 1869 and 1881, and at Oxford in 1876 and 1877.

Pritchard had a small observatory at Clapham, and joined the Royal Astronomical Society on 13 April 1849. His first contribution to their proceedings, in January 1853, was on ‘The Use of Mercury in Observations by Reflexion’ (Monthly Notices, xiii. 61). In ‘Calculations of the three Conjunctions of Jupiter and Saturn in B.C. 7, B.C. 66, and A.D. 54,’ he showed, in 1856, the inadmissibility of Ideler's identification of one of them with the star of the Magi (Memoirs, xxv. 119). He made some photometrical experiments on the annular solar eclipse of 15 March 1858 (Monthly Notices, xviii. 245), and joined the ‘Himalaya Expedition’ to Spain for observing the total eclipse of 18 July 1860. He served continuously on the council of the society from 1856 to 1877, and again from 1883 to 1887; was chosen president in 1866, and in that capacity delivered two admirable addresses in presenting gold medals to Huggins and Leverrier in 1867 and 1868 respectively.

Early in 1870 Pritchard succeeded William Fishburn Donkin [q.v.] as Savilian professor of astronomy in the university of Oxford. Although just sixty-two, he entered upon his new duties with the ardour of youth. Through his initiative convocation granted the necessary funds for the erection of a new observatory in the ‘Parks;’ the plans of the building were designed by Pritchard himself. A twelve-inch refractor was purchased from Sir Howard Grubb, and Dr. Warren de la Rue [q.v.] presented other instruments, including a thirteen-inch reflecting equatoreal, constructed by himself. The ‘New Savilian Observatory for Astronomical Physics’ was completed in 1875 (ib. xxxiv. 49, xxxv. 376, xxxvi. 1). Pritchard at once discerned the advantages of the photographic method, and applied the collodion process to an investigation of the moon's libration (Memoirs Roy. Astr. Society, xlvii. 1). He next undertook the micrometric determination of forty stars in the Pleiades, with a view to ascertain their relative displacements since Bessel's time. The results, since shown to be dubious, were published in 1884 (ib. xlviii. 357). Discordances between various estimates of the brightness of these stars led him to the invention of the ‘wedge-photometer,’ described before the Astronomical Society on 11 Nov. 1881 (ib. xlvii. 357). This instrument was criticised by Wilsing at Potsdam (Astr. Nach. No. 2680), by Langley, Young, and Pickering in America (Memoirs Amer. Acad. of Sciences, 1886, p. 301), and by Dr. Spitta in this country. Vigorously defended by Pritchard (Monthly ​Notices, xlvi. 2, 1. 512; Observatory, viii. 424, ix. 62), it has kept its place as an indispensable adjunct to photometric apparatus. By means of seventy thousand accurately observed extinctions with it he determined, in 1881–5, the relative magnitudes of 2,784 stars from the pole to ten degrees south of the equator, travelling to Cairo early in 1883 for the purpose of approximating more closely to the true value of atmospheric absorption. For the resulting valuable photometric catalogue, entitled ‘Uranometria Nova Oxoniensis,’ 1885, he received, jointly with Pickering, in February 1886, the Astronomical Society's gold medal (Monthly Notices, xlvi. 272).

Pritchard was a pioneer in the photographic measurement of stellar parallax. His trial-star was 61 Cygni, and from two hundred plates exposed in 1886 he derived a parallax of 0″.438. Encouraged by this promising result, he measured, between 1888 and 1892, twenty-eight stars, mostly of the second magnitude, obtaining, for stars of that grade of brightness, an average parallax of 0″.056, corresponding to a light-journey of fifty-eight years. The Royal Society signified their approval of this considerable performance by the bestowal, on 30 Nov. 1892, of a royal medal (Proc. Roy. Soc. lii. 312); yet Pritchard's data are undoubtedly affected by minute, insidious errors (Jacoby, Vierteljahrsschrift Astr. Gesellschaft, xxviii. 117).

Pritchard laid before the Royal Society, on 20 May 1886, a description of his elaborate ‘Researches in Stellar Photography: (1) in its Relation to the Photometry of the Stars; (2) its Applicability to Astronomical Measurements of great Precision’ (Proceedings, xl. 449). Some ‘Further Experience as regards the Magnitude of Stars obtained by Photography’ was imparted to the Royal Astronomical Society in 1891 (Monthly Notices, li. 430). He executed a series of light-measures of Nova Aurigæ in February and March 1892, both photographically and with the wedge-photometer (ib. lii. 366). His co-operation in the international scheme for charting the heavens was welcomed by the Paris congress of 1887; he received from Sir Howard Grubb one of the regulation instruments, and diligently experimented with it in 1890–1. The conclusions he thus arrived at were embodied in the ‘Compte Rendu’ of the conference in 1891 (p. 72). At the time of his death some progress had been made in photographing the zone assigned to Oxford. His ‘Report on the Capacities, in respect of Light and Photographic Action, of two Silver Glass Mirrors of different Focal Lengths’ (Proc. Roy. Soc. xli. 195) was founded on experiments undertaken at the request of the photographic committee of that body.

Elected F.R.S. on 6 Feb. 1840, Pritchard was a member of the council 1885–7. He was also a fellow of the Cambridge Philosophical Society and, from 1852, of the Geological Society. He proceeded M.A. by decree from New College, Oxford, on 11 March 1870, and D.D. in 1880; became, as Savilian professor, fellow of New College in 1883; and was, to his great delight, elected to an honorary fellowship of St. John's College, Cambridge, in 1886. He was placed on the Solar Physics Committee in 1885. He was full of plans for future work, and had, in especial, made all preparations for a photographic inquiry into the parallaxes of some of the Pleiades, when he died, after a very short illness, on 28 May 1893, in his eighty-sixth year, and was buried in Holywell cemetery, Oxford. He married, first, on 18 Dec. 1834, Emily, daughter of Mr. J. Newton; secondly, on 10 Aug. 1858, Rosalind, daughter of Mr. Alexander Campbell, who predeceased him by one year. He left children by both marriages.

Nothing could be more admirable than the ardour and originality with which Pritchard, at an advanced age, discharged the duties of his professorship. As many as fifteen students at a time were often receiving practical instruction in the subsidiary observatory fitted up for their use; Pritchard was greatly aided there by his assistants, Messrs, Plummer and Jenkin. Next to the stars, Pritchard loved flowers. He practised floriculture as a fine art, and had at Clapham one of the finest ferneries in England. Yet he would at all times have preferred parish work to his brilliant scientific avocations. ‘Providence,’ he used to say, ‘made me an astronomer, but gave me the heart of a divine.’

He published four numbers of ‘Astronomical Observations made at the University Observatory, Oxford,’ 1878–92. The first contained observations of Saturn's satellites, of four hundred double stars, and of several comets, with elements computed for these last, and for the three binaries, ξ Ursæ Majoris, 70 Ophiuchi, and μ² Bootis. No. 2 was the ‘Uranometria Nova Oxoniensis,’ 1885; Nos. 3 and 4 were devoted to stellar photographic parallax. He communicated, during the last twenty years of his life, fifty astronomical papers to learned societies; wrote many excellent popular essays, including a series in ‘Good Words;’ and contributed several articles to the ninth edition of the ‘Encyclopædia Britannica,’ and to Smith's ‘Dictionary of the Bible,’ particularly that on the ‘Star of the Wise Men.’ His ‘Occa​ sional Thoughts of an Astronomer on Nature and Revelation,' London, 1889, is a collection of miscellaneous addresses and discourses. Many of his sermons were, besides, printed separately. Finally, he edited, conjointly with Main, Sir John Herschel's 'Catalogue of Double Stars' (Memoirs Roy. Astr. Society, vol. xl. 1874).

A. M. C.