358 COSMOS. 



without quoting any precise year, that lava-ei uptions have 

 taken place during the middle ages on the south-western 

 shore of Arabia, in the insular chain of the Zobayr, in the 

 Straits of Bab-el-Mandeb and Aden (Wellsted, Travels in 

 Arabia, vol. ii, pp. 466 468), in Hadhramaut, in the Strait 

 of Ormuz, and at different points in the western portion of 

 the Persian Gulf. These eruptions have always occurred on 

 a soil which had already been in pre-historical times the seat 

 of volcanic action. The date of the eruption of a volcano at 

 Medina itself, 12| northward of the Straits of Bab-el- 

 Mandeb, was found by Burckhardt in Samhudy's Chronicle 

 of the famous city of that name in the Hedjaz. It took 

 place on the 2nd November, 1276. According to Seetzen, 

 however, Abulmahasen states that an igneous eruption had 

 occurred there in 1254, which is twenty-two years earlier 

 (see Cosmos, vol. i, p. 246). The volcanic island of Djebel- 

 tair, in which Vincent recognized the " burnt-out island " of 

 the Periplus Maria lErytJircei, is still active and emits smoke, 

 according to Botta and the accounts collected by Ehrenberg 

 and Russegger (Jteisen in Europa, Asien und Africa, Bd. ii, 

 Th, 1, 1843, s. 54). For information respecting the entire 

 district of the Straits of Bab-el-Mandeb, with the basaltic 

 island of Perini, the crater-like circumvallation, within 

 which lies the town of Aden, the island of Seerah with 

 streams of obsidian, covered with pumice, the island- 

 groupes of the Zobayr and the Farsan (the volcanic nature 

 of the latter was discovered by Ehrenberg in 1825) I refer 

 my readers to the interesting researches of Ritter in his 

 Erdkunde von Asien, Bd. viii, Abth. 1, s. 664707, 889 

 891, and 10211034. 



The volcanic mountain-chain of the Thian-schan (Asie 

 Centrale, t. i, pp. 201 203 ; t. ii, pp. 7 51), a range which 

 intersects Central Asia between Altai and Kuen-lun from 

 east to west, formed at one period the particular object of 

 my investigations, so that I have been enabled to add to the 

 few notices obtained by Abel-Remusat from the Japanese 

 Encyclopaedia, some fragments of greater importance dis- 

 covered by Klaproth, Neumann, and Stanislas Julien (Asie 

 Centrale, t. ii, pp. 3950 and 335364). The length of 

 the Thian-schan is eight times greater than that of the 

 Pyrenees, if we include the Asferah which is on the other 



