308 REACTION OF THE INTERIOR OF THE EARTH 



between the formation of conical mountains with open 

 craters on their summits, and lateral openings, or of 

 elevation-craters and maars, and the upheaval of 

 closed domes or open cones, and the direct emission of 

 substances from fissures. The greater variety of views 

 necessarily called forth by a more extended horizon of 

 observation, and the strict critical comparison of that 

 which we find in nature with what was previously 

 supposed to be the only mode of origin, is itself a most 

 powerful stimulus to investigation. Even on European 

 ground, in the island of Eubosa rich in hot springs, 

 within historic times, in the great plain of Lelantum 

 at a distance from any mountains, a great stream 

 of lava was poured forth from a fissure. ( 444 ) 



In the next group of volcanoes, the Central American 

 one, in which eighteen may still be regarded as active, 

 four (Nindiri, el Nuevo, Conseguina and San Miguel de 

 Bosotlan) have been recognised as yielding streams of 

 lava. ( 446 ) The mountains of the third group, that of 

 Popayan and Quito, have, for more than a century been 

 reputed to send forth no lava-streams, but solely masses 

 of unconnected glowing scoriae, ejected from the <>in> 

 summit-crater and often seen to glide in succession 

 down the mountain side. La Condamine was already of 

 that opinion ( 44G ) when he left the highland of Quito and 

 Cuenca, in the spring of 1743. Fourteen years later. 

 after returning from an ascent of Vesuvius (4th June, 

 1755), on which he had accompanied the sister of Fre- 

 derick the Great, the Margravine of Bavaria, he took 

 occasion, at a meeting of the Academy, to express him- 

 self strongly as to the entire absence of proper .sin -an is 

 of lava (laves coulees par torrens de matieres liquefiees) 



