248 REACTION OF THE INTERIOR OF THE EARTH 



Volcano of P.urace( 363 ) near Popayan : 17,006 feet, 

 according to Jose Caldas. 



Fifth group. From 16000 to above 20000 French 

 feet (17,052 to above 21,315 English) : 



Volcano Sangay, south-east of Quito: 17,124 feet 

 according to Bouguer and La Condamine. ( 364 ) 



Volcano Popocatepetl ( 365 ) : according to a trigono- 

 metrical measurement by Humboldt, 17,726 feet. 



Mount Elias ( 36G ) west coast of North America : 

 according to the measurements of Quadra and Gale- 

 ano, 17,851 feet. 



Volcano of Orizaba ( 367 ) 17,879 feet, according to 

 Ferrer. 



Volcano of Tolima ( 368 ) : according to a trigono- 

 metrical measurement by Humboldt, 18,129 feet. 



Cotopaxi ( 369 ) : 18,877 feet, according to Bouguer. 



Volcano of Arequipa ( 37 ) : , according to a trigono- 

 metrical measurement by Dolley, 18,879? feet. 



Volcano Sahama (in Bolivia) ( 371 ) : according to 

 Pentland, 22,349 feet. 



The volcano with which the fifth group terminates 

 is more than twice as high as Etna, and five and a half 

 times as high as Vesuvius. The graduated scale of vol- 

 canoes which we have passed in review beginning with 

 the low Maars of the Eifel (mine-funnels, without 

 external framework, which have thrown out balls of 

 olivine surrounded by half-fused schistose fragments) 

 and ending with the still active Sahama, more than 

 22,000 feet high has taught us that there is no 



