624 THE UNIVERSE. 



flame and smoke, as well as masses of cinders and burning 

 rock. In 1553, in one of its most terrible eruptions, Coto- 

 paxi projected to a distance of three leagues blocks of tra- 

 chyte more than a hundred cubic yards in size. During 

 this time the lava escapes with violence from the entrails of 

 the mountain, and pours over its sides like so many streams 

 or cascades of fire, consuming everything in their path. 



In very lofty volcanoes the lava, in order to rise to the 

 crater in which they culminate, must require an almost in- 

 calculable force ; hence it often happens that it makes its 

 way out before reaching it, and, having burst the flanks of 

 the mountain near its base, forms a small additional volcano, 

 in which, for the future, all the efforts of the eruption are 

 concentrated, and from which pour streams of lava of a 

 magnitude we should not expect from so low an elevation. 



In high volcanic mountains we often find at the base of 

 the great cone a series of small accessory volcanoes: as we 

 have seen, Etna possesses quite a family scattered over its 

 flanks. In fact, it is these that have in particular ravaged 

 the surround in ^ countries. 



The most frightful eruption of Etna in modern times was 

 produced by one of these young volcanoes, the Monte Rosa. 

 From it issued in 1771 the long river of lava which rolled 

 its burning waves over a distance of nine leagues, fired 

 great part of Catania, and only stayed its passage when it 

 plunged into the sea amidst a most tumultuous struggle be- 

 tween the waves and fire. 



Notwithstanding its smaller proportions, Vesuvius has ex- 

 perienced fearful eruptions. One is especially celebrated 

 for the destruction of two rich and important cities which 



