DEMAVEND, Morwr, an extinct volcano of Persia. It forms the loftiest peak of the Elburz chain; which separates the low shores of the Caspian sea from the high table-land of Persia. Although no longer subject to eruptions, D. bears traces of its having been an active volcano within the most recent geological epoch. Its summit is conical, covered with sulphur, and rent by heated fissures. The- crater is still visible, and the surface of the mountain is in many places covered with scoria;. At its base hot springs give evidence of the continued existence of volcanic fire at no great distance beneath the surface. A great deposit of sulphur covers the summit of D., and is brought down to the plains in bags to be disposed of as an article of commerce. Although the path that leads to the peak is, for this reason, familiar to the inhabitants of the adjoining districts, the mountain was not ascended by any European till 1837. In Sept. of that year, Mr. William T. Thomson of the English embassy at Teheran, with the view of taking important bearings from a point which commands an extensive view of the shores of the Caspian, determined to reach the summit. He set out from the base with four guides, three of whom deserted him when they experienced the effect of the rarified atmosphere on their breathing. The first night lie slept below the snow limit; the second night in a sulphur cavern near the summit, so highly heated that it was impossible to place the hand near a crevice of the interior. On leaving this place of shelter, the traveler's wet clothes were instantly frozen with a bitter blast from the Caspian. The height, as recently determined by the Russian survey, is 21,000 feet.
D. towers high above the neighboring mountains, the adjacent summits not exceed ing two thirds of its elevation. At all times it has been a conspicuous object from the great trade route between India and the west, along the edge of the Persian table-land. It is not then to be wondered at that it is connected with the earliest Persian as Etna is connected with the earliest Greek traditions. There seems indeed more than an accidental coincidence between the fables which relate to the two mountains. According to the Greeks, the giant Typhon was buried under the volcanic region of Sicily, and the earth quakes and eruptions were caused by his efforts to escape. Fire proceeded from his mouth, and he was figured with one hundred snakes growing each shoulder. Zohak, a personification of the bad principle, was in the same way supposed by the Persians to be buried under Demavend. He was figured with one serpent growing out of each shoulder; and in other respects he had much in common with the Greek monster.
or TZANA, LAKE OF, in Abyssinia, is in lat. 12° n., long. 15' e., and is 50 ni. in length, with an average breadth of 25 miles. It occupies part of an extremely fertile plain, situated at an elevation of some 6,000 ft. above the sea, and contains sev eral beautiful islands, one of which is inhabited. Its southern portion is traversed by the Blue Nile.