On Earthquakes—their causes and effects. 211 
And Newton, in no less unequivocal language, says, 
‘“‘We may Jearn that sulphureous steams abound in the 
with a great shaking of the earth, as in the springing of a 
mine.?’—Newton’s Optics, p- 353. ve 
The existence of those extensive cavities satisfactorily 
accounts to us for the fact of earthquakes being severely felt 
at great distances from volcanoes; such was the case in 
1811 and 1812, when the shores of the Mississippi, near 
New Madrid, were literaily torn to pieces, the vibration 
being felt in many parts of the United States. I was at that 
time driven from my bed in Pittsburgh by the alarming mo- 
tion. If we look round for the cause of this in a volcano 
bo 
It extended to Spain, France, Africa, the Azores, West 
Indies, &c., and persons on board ships forty leagues off 
St. Vincent were thrown from their feet. In 1601 an 
earthquake was felt in Asia, Thrace, Hungary, Bohemia, 
Germany, Italy, and France. To account satisfactorily for 
such extensive effects, we must admit of deep-seated chan- 
nels of communication stretching from one portion of the 
globe to the other, through which the explosive gases pass 
with an instantaneous motion, accompanied by a rumbling or 
terrible noise, peculiar to earthquakes. That these chan- 
nels have communication with the sea, there is no dispating ; 
for volcanoes frequently throw up salt water and fish from 
the ocean; this has been the case with Vesuvius and I be- 
lieve with some of the Cordilleras. It has been observed 
that previous to an eruption of Vesuvius, the sea retires 
from the shores until the mountain bursts, when it returns 
to overflow its usual boundaries. tna has thrown out 
than the ocean. It should here be recollected that all the 
Ses 
