rhombic system, and is sometimes found in small brilliant crystals of simple prismatic habit terminated by domal faces. More usually, however, it occurs as globular aggregates of acicular crystals, these fibrous forms often having a velvety lustre; sometimes it is lamellar in structure, or soft and earthy. A characteristic feature, and one to which the name alludes (German, Olivenerz, of A. G. Werner, 1789), is the olive-green colour, which varies in shade from blackish-green in the crystals to almost white in the finely fibrous variety known as “woodcopper.” The hardness is 3, and the sp. gr. 4·3. The mineral was formerly found in some abundance, associated with limonite and quartz, in the upper workings in the copper mines of the St Day district in Cornwall; also near Redruth, and in the Tintic district in Utah. It is a mineral of secondary origin, having been formed by the alteration of copper ores and mispickel.
The arsenic of olivenite is sometimes partly replaced by a small amount of phosphorus, and in the species libethenite we have the corresponding basic copper phosphate Cu2(OH)PO4. This is found as small dark green crystals resembling olivenite at Libethen in Hungary, and in small amount also in Cornwall. Other members of this isomorphous group of minerals are adamite, Zn2(OH)AsO4, and descloizite (q.v.). (L. J. S.)
OLIVER, ISAAC (c. 1566–1617), English miniature painter, was
probably born in London, as in 1571 a certain Peter Olivier of
Rouen was residing in London with his wife and had been there
for three years with one “chylde” named “Isake.” It would
seem likely, therefore, that he was not at that time more than
six years old. It has been suggested by Mr Lionel Cust, from the
Huguenot records, that he is identical with one Isaac Oliver of
Rouen, married at the Dutch church in Austin Friars in 1602.
His death occurred in 1617, and he was buried in the church
of St Anne, Blackfriars. He was probably a pupil of Nicholas
Hilliard, and connected through his wife, whose name is unknown,
with the artists Gheeraerts and De Critz. He was an
exceedingly expert miniature painter, and splendid examples of
his work can be seen at Montagu House, Windsor Castle, Sherborne
Castle and in the collections of Mr J. Pierpont Morgan
and the late Baroness Burdett-Coutts. Some of his pen drawings
are in the British Museum. (G. C. W.)
OLIVER, PETER (1594–1648), English miniature painter, was
the eldest son of Isaac Oliver, probably by his first wife;
and to him Isaac Oliver left his finished and unfinished
drawings, with the hope that he would live to exercise the
art of his father. The younger sons of the artist appear to
have been under age at the time of his death, and were probably
therefore sons by a later wife than the mother of Peter Oliver.
He resided at Isleworth, and was buried beside his father at
St Anne’s Blackfriars. He was even more eminent in miniature
painting than his father, and is specially remarkable for a
series of copies in water-colour he made after celebrated pictures
by old masters. Most of these were done by the desire of the
king, and seven of them still remain at Windsor Castle. A great
many of Oliver’s works were purchased by Charles II. from his
widow; several of his drawings are in existence, and a leaf from
his pocket-book in the collection of the earl of Derby. His most
important work is the group of the three grandsons of the 1st
Viscount Montacute with their servant, now belonging to the
marquess of Exeter; and there are fine miniatures by him at
Welbeck Abbey, Montagu House, Sherborne Castle, Minley
Manor, Belvoir Castle and in the private collection of the queen
of Holland. (G. C. W.)
OLIVES, MOUNT OF, or Mount Olivet (Ὄρος Ἐλαιῶνος or τῶν Ἐλαιῶν; mod. Jebel-eṭ-Ṭur), the ridge facing the Temple
Mount at Jerusalem on the east, and separated from it by the
Kidron. A basis of hard cretaceous limestone is topped with
softer deposits of the same, quaternary deposits forming the
summit. There are four distinct elevations in the ridge:
traditionally the southernmost, which is separated by a cleft from the
others, is called the “Hill of Offence,” and said to be the scene of
Solomon’s idolatry. The summit to the north of this is often
(wrongly) spoken of as Olivet proper. Still worse is the error of
calling the next hill but one to the north “Scopus.” The top of
the ridge affords a comprehensive view. There are four Old
Testament references: 2 Sam. xv. 30 sqq., Neh. viii. 15, Ezek. xi.
23, Zech. xiv. 4. In the New Testament the place is mentioned
in connexion with the last days of the life of Jesus. He crossed
it on his kingly entry into Jerusalem, and upon it he delivered
his great eschatological address (Mark xiii. 3). That the Ascension
took place from the summit of the Mount of Olives is not necessarily
implied in Acts i. 12; the words “over against Bethany”
(Luke xxiv. 50) perhaps mean one of the secluded ravines on
the eastern slope, beside one of which that village stands. But
since Constantine erected the “Basilica of the Ascension” on the
spot marked by a certain sacred cave (Euseb. Vita Const. iii. 41),
the site of this event has been placed here and marked by a
succession of churches. The present building is quite modern,
and is in the hands of the Moslems. Close to the Chapel of the
Ascension is the vault of St Pelagia, and a little way down the
hill is the labyrinth of early Christian rock-hewn sepulchral
chambers now called the “Tombs of the Prophets.” During
the middle ages Olivet was also shown as the mount of the
Transfiguration. A chapel, bearing the name of the Caliph Omar,
and said to occupy the place where he encamped when Jerusalem
surrendered to the Moslems, formerly stood beside the Church
of the Ascension. There are a considerable number of monasteries
and churches of various religious orders and sects on the hill,
from whose beauty their uniform and unredeemed ugliness
detracts sadly. On Easter day 1907 was laid the foundation
of a hospice for pilgrims, under the patronage of the German
empress.
OLIVETANS, one of the lesser monastic orders following the Benedictine Rule, founded by St Bernard Tolomei, a Sienese nobleman. At the age of forty, when the leading man in Siena, he retired along with two companions to live a hermit’s life at Accona, a desert place fifteen miles to the south of Siena, 1313. Soon others joined them, and in 1324 John XXII. approved of the formation of an order. The Benedictine Rule was taken as the basis of the life; but austerities were introduced beyond what St Benedict prescribed, and the government was framed on the mendicant, not the monastic, model, the superiors being appointed only for a short term of years. The habit is white. Partly from the olive trees that abound there, and partly out of devotion to the Passion, Accona was christened Monte Oliveto, whence the order received its name. By the end of the 14th century there were upwards of a hundred monasteries, chiefly in Italy; and in the 18th there still were eighty, one of the most famous being San Miniato at Florence. The monastery of Monte Oliveto Maggiore is an extensive building of considerable artistic interest, enhanced by frescoes of Signorelli and Sodoma; it is now a national monument occupied by two or three monks as custodians, though it could accommodate three hundred. The Olivetans have a house in Rome and a few others, including one founded in Austria in 1899. There are about 125 monks in all, 54 being priests. In America are some convents of Olivetan nuns.
See Helyot, Hist. des ordres réligieux (1718), vi. c. 24; Max Heimbucher, Orden u. Kongregationen (1907), i. § 30; Wetzer u. Welte, Kirchenlexicon (ed. 2); J. A. Symonds, Sketches and Studies in Italy (1898), “Monte Oliveto”; B. M. Maréchaux, Vie de bienheureux Bernard Tolomei (1888). (E. C. B.)
OLIVIER, JUSTE DANIEL (1807–1876), Swiss poet, was born near Nyon in the canton of Vaud; he was brought up as a peasant, but studied at the college of Nyon, and later at the academy of Lausanne. Though originally intended for the ministry, his poetic genius (foreshadowed by the prizes he obtained in 1825 and 1828 for poems on Marcos Botzaris and Julia Alpinula respectively) inclined him towards literary studies. He was named professor of literature at Neuchâtel (1830), but before taking up the duties of his post made a visit to Paris, where he completed his education and became associated with Ste Beuve, especially from 1837 onwards. He professed history at Lausanne from 1833 to 1846, when he lost his chair in consequence of the religious troubles. He then went to Paris,