as a Cause of Earthquakes. 85 



would be 31,250 pounds. As it is the property of fluids to 

 press equally in all directions, a square foot of the water, which 

 communicates with a column of it of this height, would act 

 against an upper stratum with a force equivalent to the same 

 weight. From the above it may be easily inferred, that when 

 the height of the column of water amounts to several thousand 

 feet, and there is a pressure upwards to the extent of a num- 

 ber of square miles, it may be sufficiently great to produce, by 

 sudden elevations and ruptures of the strata, the violent con- 

 cussions and upheavings which occasion the most calamitous 

 earthquakes. 



That the interiors of many mountains do contain water, is 

 well ascertained and proved by numerous facts given in vari- 

 ous treatises upon geology. During volcanic eruptions from 

 some of the Andes in South America, there are many in- 

 stances, according to Humboldt, of very large quantities of 

 water bursting from their sides. Those of Cotopaxi, Tungu- 

 ragua, and Sangay, always, from openings at the elevations of 

 2500 or 2600 toises above the level of the sea, eject a prodi- 

 gious quantity of fish along with torrents of water. At the 

 time of the last eruption of Mount Idienne, a volcano in the 

 east of the island of Java, so great a body of water was forced 

 out, that the country extending from the mountain to the sea, 

 a distance of twenty leagues, was inundated, and it gave rise 

 to two large rivers. 



The existence of extensive levels of water beneath the sur- 

 face of the soil in those districts which are liable to earth- 

 quakes is rendered probable, from this circumstance being 

 known to occur in many instances in different regions. It is 

 evident in the case of Artesian wells. The springs of fresh 

 water, some of which are very powerful, that rise from the 

 bottom of the sea, and also, as Humboldt observes, those in 

 the centres of very flat islands, for instance, the Caymans near 

 Cuba, and some of the Bermudas, must be forced upwards by 

 hydrostatical pressure from higher lands, although they are at 

 a very considerable distance. Streams of fresh water are fre- 

 quently found near the shore at the depth of several hundred 

 feet below the level of the sea, many of which most probably 

 pass under its bed. The numerous cases of rivers being wholly 



