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 _Memoires de l'Institut_,
the _Memoires de la Societe d'Agriculture de Caen_, and in other
periodical collections, he published separately _Essais historiques sur
les Bardes, les Jongleurs, et les Trouveres normands et anglo-normands_
(3 vols., 1834), and _Recherches historiques sur la Prairie de Caen_
(1837); and after his death appeared _Memoires 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
Muller 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 Romer_ (1842); T. Mommsen, _Romisches Strafrecht_
(1899); Kleinfeller in Pauly-Wissowa's _Realencyclopadie_.