ON ITS EXTERIOR. VOLCANOES. 337 



itself, 12^ degrees north of the straits of Bab-el-Mandeb, 

 has been found by Burckhardt in Samhudy's chronicle 

 of that celebrated town. It corresponds to the 

 2nd of November 1276. But we also learn from 

 Abulmahasen that an igneous eruption had taken place 

 there in 1254, or twenty-two years earlier. (Compare 

 Kosmos, Bd. i. S. 256, Eng. p. 234.) The island volcano, 

 Djebel Tair, which was already recognised by Vincent 

 as the "extinct once-burning island" of the Periplus 

 Maris Erythrsei, is still active and sends forth smoke, 

 according to Botta, and according to information 

 collected by Ehrenberg and Russegger (Reisen in 

 Europa, Asien und Afrika, Bd. ii. Th. i. 1843, S. 54). 

 Respecting the whole region round Bab-el-Mandeb, 

 with the basaltic island of Perim; the crater-like 

 encircling ridge within which the town of Aden is 

 situated ; the island of Seerah with streams of obsidian 

 which are covered with pumice ; and respecting the 

 groups of islands of Zobayr and Farsan (the volcanic 

 character of the latter was discovered by Ehrenberg in 

 1825), see the fine investigations of Ritter in his 

 Erdkunde von Asien, Bd. viii. Abth. 1. S. 664 707, 

 889891, and 10211034. 



The volcanic range of the Thian-schan (Asie centrale, 

 t. i. p. 201 203, t. ii. p. 7 61), a mountain system 

 extending from west to east across Central Asia from 

 the Altai to the Kuen-lun, was at one time an especial 

 object of study to me, when to the little which Abel 

 Remusat had obtained concerning it from the Japanese 

 Encyclopedia, I was able to add the more important 

 fragmentary notices discovered by Klaproth, Neumann, 

 and Stanislas Julien (Asie centrale, t. ii. p. 39 50 and 



VOL. iv z 



