His work, the _Kitab ul-Bayan wat-Tabyin_, a discursive treatise on rhetoric, has been published in two volumes at Cairo (1895). The _Kitab ul-Mahasin wal-Addad_ was edited by G. van Vloten as _Le Livre des beautés et des antithèses_ (Leiden, 1898); the _Kitab ul-Bu-hala_. _Le Livre des avares_, ed. by the same (Leiden, 1900); two other smaller works, the _Excellences of the Turks_ and the _Superiority in Glory of the Blacks over the Whites_, also prepared by the same. The _Kitab ul-Hayawan,_ or "Book of Animals," a philological and literary, not a scientific, work, was published at Cairo (1906). (G. W. T.) JAHN, FRIEDRICH LUDWIG (1778-1852), German pedagogue and patriot, commonly called _Turnvater_ ("Father of Gymnastics"), was born in Lanz on the 11th of August 1778. He studied theology and philology from 1796 to 1802 at Halle, Göttingen and Greifswald. After Jena he joined the Prussian army. In 1809 he went to Berlin, where he became a teacher at the Gymnasium zum Grauen as well as at the Plamann School. Brooding upon the humiliation of his native land by Napoleon, he conceived the idea of restoring the spirits of his countrymen by the development of their physical and moral powers through the practice of gymnastics. The first _Turnplatz_, or open-air gymnasium, was opened by him at Berlin in 1811, and the movement spread rapidly, the young gymnasts being taught to regard themselves as members of a kind of gild for the emancipation of their fatherland. This patriotic spirit was nourished in no small degree by the writings of Jahn. Early in 1813 he took an active part at Breslau in the formation of the famous corps of Lützow, a battalion of which he commanded, though during the same period he was often employed in secret service. After the war he returned to Berlin, where he was appointed state teacher of gymnastics. As such he was a leader in the formation of the student _Burschenschaften_ (patriotic fraternities) in Jena. A man of democratic nature, rugged, honest, eccentric and outspoken, Jahn often came into collision with the reactionary spirit of the time, and this conflict resulted in 1819 in the closing of the _Turnplatz_ and the arrest of Jahn himself. Kept in semi-confinement at the fortress of Kolberg until 1824, he was then sentenced to imprisonment for two years; but this sentence was reversed in 1825, though he was forbidden to live within ten miles of Berlin. He therefore took up his residence at Freyburg on the Unstrut, where he remained until his death, with the exception of a short period in 1828, when he was exiled to Cölleda on a charge of sedition. In 1840 he was decorated by the Prussian government with the Iron Cross for bravery in the wars against Napoleon. In the spring of 1848 he was elected by the district of Naumburg to the German National Parliament. Jahn died on the 15th of October 1852 in Freyburg, where a monument was erected in his honour in 1859.