De La Rue, Warren (1815-1889), British astronomer and chemist, son of Thomas De la Rue, the founder of the large firm of stationers of that name in London, was born in Guernsey on the 18th of January 1815. Having completed his education in Paris, he entered his father’s business, but devoted his leisure hours to chemical and electrical researches, and between 1836 and 1848 published several papers on these subjects. Attracted to astronomy by the influence of James Nasmyth, he constructed in 1850 a 13-in. reflecting telescope, mounted first at Canonbury, later at Cranford, Middlesex, and with its aid executed many drawings of the celestial bodies of singular beauty and fidelity. His chief title to fame, however, is his pioneering work in the application of the art of photography to astronomical research. In 1851 his attention was drawn to a daguerreotype of the moon by G. P. Bond, shown at the great exhibition of that year. Excited to emulation and employing the more rapid wet-collodion process, he succeeded before long in obtaining exquisitely defined lunar pictures, which remained unsurpassed until the appearance of the Rutherfurd photographs in 1865. In 1854 he turned his attention to solar physics, and for the purpose of obtaining a daily photographic representation of the state of the solar surface he devised the photo-heliograph, described in his report to the British Association, “On Celestial Photography in England” (1859), and in his Bakerian Lecture (Phil. Trans. vol. clii. pp. 333-416). Regular work with this instrument, inaugurated at Kew by De la Rue in 1858, was carried on there for fourteen years; and was continued at the Royal Observatory, Greenwich, from 1873 to 1882. The results obtained in the years 1862-1866 were discussed in two memoirs, entitled “Researches on Solar Physics,” published by De la Rue, in conjunction with Professor Balfour Stewart and Mr B. Loewy, in the Phil. Trans. (vol. clix. pp. 1-110, and vol. clx. pp. 389-496). In 1860 De la Rue took the photo-heliograph to Spain for the purpose of photographing the total solar eclipse which occurred on the 18th of July of that year. This expedition formed the subject of the Bakerian Lecture already referred to. The photographs obtained on that occasion proved beyond doubt the solar character of the prominences or red flames, seen around the limb of the moon during a solar eclipse. In 1873 De la Rue gave up active work in astronomy, and presented most of his astronomical instruments to the university observatory, Oxford. Subsequently, in the year 1887, he provided the same observatory with a 13-in. refractor to enable it to take part in the International Photographic Survey of the Heavens. With Dr Hugo Müller as his collaborator he published several papers of a chemical character between the years 1856 and 1862, and investigated, 1868-1883, the discharge of electricity through gases by means of a battery of 14,600 chloride of silver cells. He was twice president of the Chemical Society, and also of the Royal Astronomical Society (1864-1866). In 1862 he received the gold medal of the latter society, and in 1864 a Royal medal from the Royal Society, for his observations on the total eclipse of the sun in 1860, and for his improvements in astronomical photography. He died in London on the 19th of April 1889.
See Monthly Notices Roy. Astr. Soc. l. 155; Journ. Chem. Soc. lvii. 441; Nature, xl. 26; The Times (April 22, 1889); Royal Society, Catalogue of Scientific Papers.
