THE COASTS OF SICILY. 131 



Man is small and feeble, but full of pride, and he 

 always takes himself as the unit, and as a term of 

 comparison. He measures the globe and the universe 

 by his own stature, and the infinite powers of nature 

 by his own forces. In his eyes, Etna, that blow-hole 

 which is scarcely perceptible upon our planet, which 

 is about 24,000 miles in circumference, is a gigantic 

 mountain, and he starts back in amazement at the 

 forces which are required to upheave it. It is not 

 very difficult, however, to convince oneself that in 

 volcanic phenomena the energy of the cause is fully 

 in harmony with the greatness of the effects. 



Let us then, by way of illustration, inquire what 

 relation exists between the forces employed at the 

 present day by industrial science and those which 

 slumber within the crater of Etna. Let us suppose, 

 and the assumption is by no means an exaggerated 

 one, that this crater is 500 yards in diameter, and 

 that it penetrates below the earth to a depth equal 

 to the height of the mountain. 



The magnificent steam engines which exhaust the 

 air on the atmospheric line of Saint-Germain, have ti 

 400-horse power. They act under a pressure of six 

 atmospheres, and their pistons present a surface of 

 more than three square yards. In approximate calcu- 



Parts of tho World. Volcanoes Volcanoes 



of Continents. of Islands. Total. 



Europe - - - - 4 - 18 - 22 



Asia - - - 55 - 71-126 



Africa - - - - 13 - 12 - . 25 



America- - - - 114 - 90 - 204 



The Ocean - - - -183-182 



Total 186 373 559 



(Nouveau Cours dementaire de Geologic, by J.-J.-N. Iltiot.) 

 K 2 



