350 Volcanoes. 



Guadaloupe and Montserrat are also the sites of volcanic 

 action. 



In the Aleutian Isles there are six active cones, namely, 

 Kanaga, Tatavanga, Oominga, Oomilaska, Omnak, and 

 Ourimak. 



How imperfect soever this brief review of the geographical 

 position of the known active volcanoes may be, it cannot fail 

 to give some adequate notion of the great extent of sub- 

 terranean fires. Those who have never witnessed the phe- 

 nomena that accompany eruption, or examined its effects, are 

 not perhaps able to conceive the power of this wonderful 

 agent; but the above statements may prevent them from 

 the error of supposing that it is partial in the extent of its 

 action. 



The deductions which may be drawn from our knowledge of 

 the locality of volcanoes are peculiarly important and inter- 

 esting. The first observation that we make is, that almost 

 all the active cones are situated in the immediate neighbour- 

 hood of the sea, or some large saltwater lake. The greater num- 

 ber are found in islands, many of which seem to have been 

 the products of their activity. Some few exceptions, however, 

 may be made to this rule, particularly in the case of the 

 American volcanoes, a few of which are situated in the interior 

 of the continent, far from the sea ; but none at a greater dis- 

 tance than 50 leagues ; and we are not acquainted with any 

 instances, except in the volcanoes of Asia, in which there is 

 not abundant reason to believe that they are connected with 

 other volcanoes, which are on the borders of the ocean. The 

 volcano of Jorullo is more distant from the sea than any other ; 

 yet, on one hand, it is connected with the Atlantic by Tuxtla, 

 and on the other with the Pacific by Colima. 



Another observation, deduced from the geographical position 

 of volcanoes, is, that they are generally arranged in lines. It 

 is true, volcanoes are sometimes solitary, and seem to have 

 no connection with the surrounding mountains : such is the 

 case with Etna and the Peak of TenerifFe. At other times 

 we observe them in irregular groups, as in the Grecian Archi- 

 pelago : but their most common arrangement is in lines. This 

 is generally the case in South America ; and suggested to 

 Humboldt the idea that they were ranged over an immense 

 chasm of intumescent matter. From the knowledge we have 

 of the geological character of the situations in which vol- 

 canoes occur, one other observation may be deduced, that 

 they are not confined to countries of any particular geological 

 formation, but may be found in all parts of the series, from 

 the tertiary to the primitive. 



(To be continued.') 



