346 COSMOS. 



and solfataras, belonging to one and the same system, have 

 been referred to as distinct volcanoes. The magnitude 

 of the space in the interior of continents which has 

 hitherto remained closed to all scientific investigation, has 

 not been so great an obstacle to the solidity of this work as 

 is commonly supposed, as islands and regions near the coast 

 are generally the principal seat of volcanoes. In a numerical 

 investigation, which cannot be brought to a -full conclusion 

 in the present state of our knowledge, much is already 

 gained when we attain to a result which is to be regarded 

 as a lower limit, and when we can determine with great 

 probability upon how many points the fluid interior of our 

 earth has remained in active communication with the atmo- 

 sphere within the historical period. Such an activity 

 usually manifests itself simultaneously in eruptions from 

 volcanic platforms (conical mountains), in the increasing heat 

 and inflammability of thermal springs and naphtha wells, 

 and in the increased extent of circles of commotion, phe- 

 nomena which all stand in intimate connection and in mu- 

 tual dependence 38 . Here again, also, Leopold von Buch has 

 the great merit of having (in the supplements to the Phy- 

 sical Description of the Canary Islands] for the first time 

 undertaken to bring the volcanic system of the whole earth, 

 after the fundamental distinction of Central and Linear Vol- 

 canoes, under one cosmical point of view. My own more 

 recent, and, probably for this reason, more complete enumera- 

 tion, undertaken in accordance with principles which I have 

 already indicated (pp. 245 and 271) and therefore excluding 

 unopened bell-shaped mountains and mere eruptive cones, 

 gives, as the probable lower numerical limit (noinbre limite 

 inferieur), a result which differs considerably from all pre- 



33 " The hot springs of Saragyn at the height of fully 5600 feet are re- 

 markable for the part played by the carbonic acid gas which traverses 

 them at the period of earthquakes. At this epoch, the gas, like the car- 

 bonated hydrogen of the peninsula of Apscheron, increases in volume 

 and becomes heated, before and during the earthquakes in the plain of 

 Ardebil. In the peninsula of Apscheron, the temperature rises 36, 

 until spontaneous inflammation occurs at the moment when and the 

 spot where an igneous eruption takes place, which is always prognosti- 

 cated by earthquakes in the provinces of Chemakhi and Apscheron." 

 Abich, in the Melanges Physiques et Chimiques, t. ii, 1855, pp. 364 36a 

 (see Cosmos, vol. v, p. 175). 



