332 REACTION OF THE INTERIOR OF THE EARTH 



(19th of May 1806), and the Asiatic Society in Calcutta, 

 in 1836, had laid before them ashes collected on two 

 different occasions at the same spot. According to very 

 careful inquiries by Daussy, it appears that on five 

 occasions, from 1747 to Krusenstern's voyage of circum- 

 navigation, and on seven occasions, from 1806 to 1836, 

 navigators within this volcanic region (as it is called in 

 the recent fine American chart of Lieut. Samuel Lee, 

 Track of the Surveying Brig Dolphin, 1854) have 

 remarked strange heavings of the sea, and shocks to 

 their vessels, which have been attributed to agitation of 

 the bottom of the sea by earthquake movements. Yet 

 very recently (Jan. 1852), in the Expedition of the 

 Brig Dolphin, which was instructed to take soundings 

 between the equator and 7 S. lat. and between 16 and 

 25 W. long., with reference to " Krusenstern's volcano," 

 nothing remarkable was perceived, as had also been the 

 case in Wilkes's Exploring Expedition. 



3. Africa. 



The volcano Mongo-ma Leba in the Cameroon moun- 

 tains (N. lat. 4 12') west of the mouth of the river of 

 the same name, in the Bight of Biafra, east of the 

 Delta of the Quorra or Niger, according to Captain 

 Allen, emitted a stream of lava in 1838. The line of 

 direction of four lofty volcanic islands, Annabona, 

 St. Thomas, Prince's Island, and Fernando Po, over a 

 S.S.W. N.N.E. fissure, points to the Cameroon mountain 

 which, according to Captain Owen and Lieutenant 

 Boteler, reaches the great height of about 13,000 

 feet. ( 478 ) 



