An exhaustive description of jade will be found in a sumptuous work, entitled _Investigations and Studies in Jade_ (New York, 1906). This work, edited by Dr G. F. Kunz, was prepared in illustration of the famous jade collection made by Heber Reginald Bishop, and presented by him to the Metropolitan Museum of Art, New York. The work, which is in two folio volumes, superbly illustrated, was printed privately, and after 100 copies had been struck off on American hand-made paper, the type was distributed and the material used for the illustrations was destroyed. The second volume is a catalogue of the collection, which comprises 900 specimens arranged in three classes: mineralogical, archaeological and artistic. The important section on Chinese jade was contributed by Dr S. W. Bushell, who also translated for the work a discourse on jade--_Yü-shuo_ by T'ang Jung-tso, of Peking. Reference should also be made to Heinrich Fischer's _Nephrit und Jadeit_ (2nd ed., Stuttgart, 1880), a work which at the date of its publication was almost exhaustive. (F. W. R.*) FOOTNOTE: [1] The English use of the word for a worthless, ill-tempered horse, a "screw," also applied as a term of reproach to a woman, has been referred doubtfully to the same Spanish source as the O. Sp. _ijadear_, meaning to pant, of a broken-winded horse. JAEN, an inland province of southern Spain, formed in 1833 of districts belonging to Andalusia; bounded on the N. by Ciudad Real and Albacete, E. by Albacete and Granada, S. by Granada, and W. by Cordova. Pop. (1900), 474,490; area, 5848 sq. m. Jaen comprises the upper basin of the river Guadalquivir, which traverses the central districts from east to west, and is enclosed on the north, south and east by mountain ranges, while on the west it is entered by the great Andalusian plain. The Sierra Morena, which divides Andalusia from New Castile, extends along the northern half of the province, its most prominent ridges being the Loma de Chiclana and the Loma de Ubeda; the Sierras de Segura, in the east, derive their name from the river Segura, which rises just within the border; and between the last-named watershed, its continuation the Sierra del Pozo, and the parallel Sierra de Cazorla, is the source of the Guadalquivir. The loftiest summits in the province are those of the Sierra Magina (7103 ft.) farther west and south. Apart from the Guadalquivir the only large rivers are its right-hand tributaries the Jándula and Guadalimar, its left-hand tributary the Guadiana Menor, and the Segura, which flows east and south to the Mediterranean.