360 ON VOLCANOES AND EARTHQUAKES, 



the volcanoes smoke, without burning, for a long 

 period : while others emit flames, without either smoke 

 or lava. In some of the eruptions of .ZEtna, minute 

 fragments and dust have been thrown out, while the 

 mountain only smoked in its usual tranquil manner. 

 Many of the volcanoes of Quito eject flames, water, and 

 mud, without lava. Even fish, almost living, or re- 

 cently dead, are sometimes thrown out with the water. 



The eruption of a volcano for the first time, is 

 attended with some difference in the phenomena, 

 though these have hitherto been examined only in 

 volcanic countries, That of Jorullo was preceded by 

 earthquakes for a considerable period ; after which a 

 large tract of ground rose to a height of more than 

 five hundred feet, forming a convex hill, whence issued 

 flames extending over a wide space, together with 

 fragments of heated rocks. This surface was in a 

 state of undulation resembling that of the sea, and two 

 rivers were swallowed up in the abysses which it 

 formed. Torrents of mud with stones were then 

 thrown out, and numerous cones arose in the neigh- 

 bourhood ; while one large chasm was formed, whence 

 were projected masses so bulky as to form hills of 

 sixteen hundred feet in height. Jorullo itself, still 

 burning, is the highest of these. 



In the history of this eruption we can trace the 

 origin of those chains which were formed on the 

 declivity of JEtna in 1809, and on that of Vesuvius 

 in 1760- It is probable that similar phenomena ac- 

 companied others long since extinct ; such as those of 

 Auvergne, which are ranged in a line of sixty miles 

 in length. Thus also, successive eruptions may at 

 some future period raise Jorullo to the height of 

 Vesuvius or jEtna. It is easy also to understand, 

 how an eruption thus taking place for the first time. 



