DELARUE, GERVAIS (1751-1835), French historical investigator, formerly regarded as one of the chief authorities on Norman and Anglo-Norman literature, was a native of Caen. He received his education at the university of that town, and was ultimately raised to the rank of professor. His first historical enterprise was interrupted by the French Revolution, which forced him to take refuge in England, where he took the opportunity of examining a vast mass of original documents in the Tower and elsewhere, and received much encouragement, from Sir Walter Scott among others. From England he passed over to Holland, still in prosecution of his favourite task; and there he remained till in 1798 he returned to France. The rest of his life was spent in his native town, where he was chosen principal of his university. While in England he had been elected a member of the Royal Society of Antiquaries; and in his own country he was made a corresponding member of the Institute, and was enrolled in the Legion of Honour. Besides numerous articles in the Memoirs of the Royal Society of London, the Mémoires de l’Institut, the Mémoires de la Société d’Agriculture de Caen, and in other periodical collections, he published separately Essais historiques sur les Bardes, les Jongleurs, et les Trouvères normands et anglo-normands (3 vols., 1834), and Recherches historiques sur la Prairie de Caen (1837); and after his death appeared Mémoires historiques sur le palinod de Caen (1841), Recherches sur la tapisserie de Bayeux (1841), and Nouveaux Essais historiques sur la ville de Caen (1842). In all his writings he displays a strong partiality for everything Norman, and rates the Norman influence on French and English literature as of the very highest moment.
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.
DELATOR, in Roman history, properly one who gave notice (deferre) to the treasury officials of moneys that had become due to the imperial fisc. This special meaning was extended to those who lodged information as to punishable offences, and further, to those who brought a public accusation (whether true or not) against any person (especially with the object of getting money). Although the word delator itself, for “common informer,” is confined to imperial times, the right of public accusation had long been in existence. When exercised from patriotic and disinterested motives, its effects were beneficial; but the moment the principle of reward was introduced, this was no longer the case. Sometimes the accuser was rewarded with the rights of citizenship, a place in the senate, or a share of the property of the accused. At the end of the republican period, Cicero (De Officiis, ii. 14) expresses his opinion that such accusations should be undertaken only in the interests of the state or for other urgent reasons. Under the empire the system degenerated into an abuse, which reached its height during the reign of Tiberius, although the delators continued to exercise their activity till the reign of Theodosius. They were drawn from all classes of society,—patricians, knights, freedmen, slaves, philosophers, literary men, and, above all, lawyers. The objects of their attacks were the wealthy, all possible rivals of the emperor, and those whose conduct implied a reproach against the imperial mode of life. Special opportunities were afforded by the law of majestas, which (originally directed against attacks on the ruler by word or deed) came to include all kinds of accusations with which it really had nothing to do; indeed, according to Tacitus, a charge of treason was regularly added to all criminal charges. The chief motive for these accusations was no doubt the desire of amassing wealth,[1] since by the law of majestas one-fourth of the goods of the accused, even if he committed suicide in order to avoid confiscation (which was always carried out in the case of those condemned to capital punishment), was assured to the accuser (who was hence called quadruplator). Pliny and Martial mention instances of enormous fortunes amassed by those who carried on this hateful calling. But it was not without its dangers. If the delator lost his case or refused to carry it through, he was liable to the same penalties as the accused; he was exposed to the risk of vengeance at the hands of the proscribed in the event of their return, or of their relatives; while emperors like Tiberius would have no scruples about banishing or putting out of the way those of his creatures for whom he had no further use, and who might have proved dangerous to himself. Under the better emperors a reaction set in, and the severest penalties were inflicted upon the delators. Titus drove into exile or reduced to slavery those who had served Nero, after they had first been flogged in the amphitheatre. The abuse naturally reappeared under a man like Domitian; the delators, with whom Vespasian had not interfered, although he had abolished trials for majestas, were again banished by Trajan, and threatened with capital punishment in an edict of Constantine; but, as has been said, the evil, which was an almost necessary accompaniment of autocracy, lasted till the end of the 4th century.
See Mayor’s note on Juvenal iv. 48 for ancient authorities; C. Merivale, Hist. of the Romans under the Empire, chap. 44; W. Rein, Criminalrecht der Römer (1842); T. Mommsen, Römisches Strafrecht (1899); Kleinfeller in Pauly-Wissowa’s Realencyclopädie.
[1] “Delatores, genus hominum publico exitio repertum ... per praemia eliciebantur” (Tacitus, Annals, iv. 30).