As regards the English oath, usually "By Jingo," or "By the living Jingo," the derivation is doubtful. The identification with the name of Gingulph or Gengulphus, a Burgundian saint who was martyred on the 11th of May 760, was a joke on the part of R. H. Barham, author of the _Ingoldsby Legends_. Some explain the word as a corruption of Jainko, the Basque name for God. It has also been derived from the Persia _jang_ (war), St Jingo being the equivalent of the Latin god of war, Mars; and is even explained as a corruption of "Jesus, Son of God," Je-n-go. In support of the Basque derivation it is alleged that the oath was first common in Wales, to aid in the conquest of which Edward I. imported a number of Basque mercenaries. The phrase does not, however, appear in literature before the 17th century, first as conjurer's jargon. Motteux, in his "Rabelais," is the first to use "by jingo," translating _par dieu_. The political use of the word as indicating an aggressive patriotism (Jingoes and Jingoism) originated in 1877 during the weeks of national excitement preluding the despatch of the British Mediterranean squadron to Gallipoli, thus frustrating Russian designs on Constantinople. While the public were on the tiptoe of expectation as to what policy the government would pursue, a bellicose music-hall song with the refrain "We don't want to fight, but by Jingo if we do," &c., was produced in London by a singer known as "the great MacDermott," and instantly became very popular. Thus the war-party came to be called Jingoes, and Jingoism has ever since been the term applied to those who advocate a national policy of arrogance and pugnacity. For a discussion of the etymology of Jingo see _Notes and Queries_, (August 25, 1894), 8th series, p. 149. JINN (DJINN), the name of a class of spirits (_genii_) in Arabian mythology. They are the offspring of fire, but in their form and the propagation of their kind they resemble human beings. They are ruled by a race of kings named "Suleyman," one of whom is considered to have built the pyramids. Their central home is the mountain Kaf, and they manifest themselves to men under both animal and mortal form and become invisible at will. There are good and evil jinn, and these in each case reach the extremes of beauty and ugliness. JIRECEK, JOSEF (1825-1888), Czech scholar, was born at Vysoké Mýto in Bohemia on the 9th of October 1825. He entered the Prague bureau of education in 1850, and became minister of the department in the Hohenwart cabinet in 1871. His efforts to secure equal educational privileges for the Slav nationalities in the Austrian dominions brought him into disfavour with the German element. He became a member of the Bohemian Landtag in 1878, and of the Austrian Reichsrat in 1879. His merits as a scholar were recognized in 1875 by his election as president of the royal Bohemian academy of sciences. He died in Prague on the 25th of November 1888.