IDRIA, a mining town in Carniola, Austria, 25 m. W. of Laibach. Pop. (1900) 5772. It is situated in a narrow Alpine valley, on the river Idria, an affluent of the Isonzo, and owes its prosperity to the rich mines of quicksilver which were accidentally discovered in 1497. Since 1580 they have been under the management of the government. The mercurial ore lies in a bed of clay slate, and is found both mingled with schist and in the form of cinnabar. A special excellence of the ore is the greatness of the yield of pure metal compared with the amount of the refuse. As regards the quantity annually extracted, the mines of Idria rank second to those of Almaden in Spain, which are the richest in the world.
IDRIALIN, a mineral wax accompanying the mercury ore in
Idria. According to Goldschmidt it can be extracted by means
of xylol, amyl alcohol or turpentine; also without decomposition,
by distillation in a current of hydrogen, or carbon dioxide.
It is a white crystalline body, very difficultly fusible, boiling
above 440° C. (824° F.), of the composition C40H28O. Its solution
in glacial acetic acid, by oxidation with chromic acid, yielded
a red powdery solid and a fatty acid fusing at 62° C., and
exhibiting all the characters of a mixture of palmitic and
stearic acids.
IDRISI, or Edrisi [Abu Abdallah Mahommed Ibn Mahommed Ibn Abdallah Ibn Idrisi, c. A.D. 1099–1154], Arabic geographer. Very little is known of his life. Having left Islamic lands and become the courtier and panegyrist of a Christian prince, though
himself a descendant of the Prophet, he was probably regarded
by strict Moslems as a scandal, whose name should not, if
possible, be mentioned. His great-grandfather, Idrisi II.,
“Biamrillah,” a member of the great princely house which had
reigned for a time as caliphs in north-west Africa, was prince
of Malaga, and likewise laid claim to the supreme title (Commander
of the Faithful). After his death in 1055, Malaga was
seized by Granada (1057), and the Idrisi family then probably
migrated to Ceuta, where a freedman of theirs held power. Here
the geographer appears to have been born in A.H. 493 (A.D. 1099).
He is said to have studied at Cordova, and this tradition is confirmed
by his elaborate and enthusiastic description of that
city in his geography. From this work we know that he had
visited, at some period of his life before A.D. 1154, both Lisbon
and the mines of Andalusia. He had also once resided near
Morocco city, and once was at (Algerian) Constantine. More
precisely, he tells us that in A.D. 1117 he went to see the cave
of the Seven Sleepers at Ephesus; he probably travelled extensively
in Asia Minor. From doubtful readings in his text
some have inferred that he had seen part of the coasts of France
and England. We do not know when Roger II. of Sicily (1101–1154)
invited him to his court, but it must have been between
1125 and 1150. Idrisi made for the Norman king a celestial
sphere and a disk representing the known world of his day—both
in silver. These only absorbed one-third of the metal
that had been given him for the work, but Roger bestowed on
him the remaining two-thirds as a present, adding to this 100,000
pieces of money and the cargo of a richly-laden ship from
Barcelona. Roger next enlisted Idrisi’s services in the compilation
of a fresh description of the “inhabited earth” from
observation, and not merely from books. The king and his
geographer chose emissaries whom they sent out into various
countries to observe, record and design; as they returned,
Idrisi inserted in the new geography the information they
brought. Thus was gradually completed (by the month of
Shawwal, A.H. 548 = mid-January, A.D. 1154), the famous work,
best known, from its patron and originator, as Al Rojari, but
whose fullest title seems to have been, The going out of a Curious
Man to explore the Regions of the Globe, its Provinces, Islands,
Cities and their Dimensions and Situation. This has been
abbreviated to The Amusement of him who desires to traverse
the Earth, or The Relaxation of a Curious Mind. The title of
Nubian Geography, based upon Sionita and Hezronita’s misreading
of a passage relating to Nubia and the Nile, is entirely
unwarranted and misleading. The Rogerian Treatise contains
a full description of the world as far as it was known to the
author. The “inhabited earth” is divided into seven “climates,”
beginning at the equinoctial line, and extending northwards
to the limit at which the earth was supposed to be rendered
uninhabitable by cold. Each climate is then divided by perpendicular
lines into eleven equal parts, beginning with the
western coast of Africa and ending with the eastern coast of
Asia. The whole world is thus formed into seventy-seven equal
square compartments. The geographer begins with the first
part of the first climate, including the westernmost part of the
Sahara and a small (north-westerly) section of the Sudan (of
which a vague knowledge had now been acquired by the Moslems
of Barbary), and thence proceeds eastward through the different
divisions of this climate till he finds its termination in the Sea
of China. He then returns to the first part of the second climate,
and so proceeds till he reaches the eleventh part of the seventh
climate, which terminates in north-east Asia, as he conceives
that continent. The inconveniences of the arrangement (ignoring
all divisions, physical, political, linguistic or religious, which
did not coincide with those of his “climates”) are obvious.
Though Idrisi was in such close relations with one of the most civilized of Christian courts and states, we find few traces of his influence on European thought and knowledge. The chief exception is perhaps in the delineation of Africa in the world-maps of Marino Sanuto (q.v.) and Pietro Vesconte. His account of the voyage of the Maghrurin or “Deceived Men” of Lisbon in the Atlantic (a voyage on which they seem to have visited Madeira and one of the Canaries) may have had some effect in stimulating the later ocean enterprise of Christian mariners; but we have no direct evidence of this. Idrisi’s Ptolemaic leanings give a distinctly retrograde character to certain parts of his work, such as east Africa and south Asia; and, in spite of the record of the Lisbon Wanderers, he fully shares the common Moslem dread of the black, viscous, stormy and wind-swept waters of the western ocean, whose limits no one knew, and over which thick and perpetual darkness brooded. At the same time his breadth of view, his clear recognition of scientific truths (such as the roundness of the world) and his wide knowledge and intelligent application of preceding work (such as that of Ptolemy, Masudi and Al Jayhani) must not be forgotten. He also preserves and embodies a considerable amount of private and special information—especially as to Scandinavia (in whose delineation he far surpasses his predecessors), portions of the African coast, the river Niger (whose name is perhaps first to be found, after Ptolemy’s doubtful Nigeir, in Idrisi), portions of the African coast, Egypt, Syria, Italy, France, the Adriatic shore-lands, Germany and the Atlantic islands. No other Arabic work contains a larger assortment of valuable geographical facts; unfortunately the place-names are often illegible or hopelessly corrupted in the manuscripts. Idrisi’s world-map, with all its shortcomings, is perhaps the best product of that strangely feeble thing—the Mahommedan cartography of the middle ages.
Besides the Rojari, Idrisi wrote another work, largely geographical, cited by Abulfida as The Book of Kingdoms, but apparently entitled by its author The Gardens of Humanity and the Amusement of the Soul. This was composed for William the Bad (1154–1166), son and successor of Roger II., but is now lost. He likewise wrote, according to Ibn Said, on Medicaments, and composed verses, which are referred to by the Sicilian Mahommedan poet Ibn Bashrun.
Two manuscripts of Idrisi exist in the Bibliothèque Nationale, Paris, and other two in the Bodleian Library, Oxford. One of the English MSS., brought from Egypt by Greaves, is illustrated by a map of the known world, and by thirty-three sectional maps (for each part of the first three climates). The second manuscript, brought by Pococke from Syria, bears the date of A.H. 906, or A.D. 1500. It consists of 320 leaves, and is illustrated by one general and seventy-seven particular maps, the latter consequently including all the parts of every climate. The general map was published by Dr Vincent in his Periplus of the Erythraean Sea. A copy of Idrisi’s work in the Escorial was destroyed by the fire of 1671.
An epitome of Idrisi’s geography, in the original Arabic, was printed, with many errors, in 1592 at the Medicean press in Rome, from a MS. preserved in the Grand Ducal library at Florence (De geographia universali. Hortulus cultissimus . . . ). Even the description of Mecca is here omitted. Pococke supplied it from
