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.