VOLCANOES 



resulting from lava-discharges, a problem which Mr. E. 

 D. Preston has begun to solve by pendulum observations, 

 and there is reason to hope may continue to investigate 

 to its complete solution ; and, besides, if admitting of 

 field study, the movements of the lavas in the great lava- 

 columns, and the source or sources of the ascensive 

 movement. 



' The geologist who is capable of investigating these 

 subjects will find other inquiries rising as his work goes 

 forward. ' ' 



247 



