2. The mountain system of the Thian-schan, or Celestial Mountains, the Tengri-tagh of the Turks (Tukiu) and of the kindred race of the Hiongnu, is eight times as long, in an east and west direction, as the Pyrenees. Beyond,--_i. e._ west of its intersection with the transverse or north and south chain of the Bolor and Kosuyrt, the Thian-schan bears the names of Asferah and Aktagh, is rich in metals, and has open fissures, which emit hot vapours, luminous at night, and which are used for obtaining sal-ammoniac. (Asie Centrale, T. ii. p. 18-20.) East of the transverse Bolor and Kosyurt chain, there follow successively in the Thian-schan,--the Kashgar Pass (Kaschgar-dawan); the Glacier Pass of Djeparle, which leads to Kutch and Aksu in the Tarim basin; the volcano of Pe-schan, which sent forth fire and streams of lava at least as late as the middle of the seventh century; the great snow-covered massive elevation Bogdo-Oola; the Sol-fatara of Urumsti, which furnishes sulphur and sal-ammoniac (nao-scha), and is situated in a coal district; the still active volcano of Turfan (or volcano of Ho-tscheu or Bischbalik), almost midway between the meridians of Turfan (Kune-Turpan), and of Pidjan. The volcanic eruptions of the Thian-schan chain, recorded by Chinese historians, reach as far back as the year 89, A.D., when the Hiongnu of the sources of the Irtysh were pursued by the Chinese army as far as Kutch and Kharaschar (Klaproth, Tableau hist. de l’Asie, p. 108). The Chinese General, Teu-hian, surmounted the Thian-schan, and saw “the Fire Mountains which send out masses of molten rock that flow for many Li.”