On Volcanos and Earthquakes. 19 
are exhausted, when the lava has flowed out for 
some tim athe eruption decreases, and finally is mn ha 
cause fe column of lava in the crater, being of a density 
superior to the water of the sea, chokes the A tera and the 
volcano must then resume its quiet operatio 
ut, why should I endeavour to describe what must hap: 
pen? Let us rather ascertain what has happened, and see 
i the facts recorded agree with the shabey here pre- 
nted. 
“One of the first ee who gives an account of Ve- 
vius, is, I believe, Pliny the younger. e read in his 
Epist. XX, x ib. vi. fees remarkable words: 
_ oe mare in se resorberi et tremore terre quasi repelli 
vide s. Certé processerat littus, multa animalia maris sic- 
cis arenis ng eer Ab altero latere nubes atra et horrenda 
ignei spiritds tortis vibratisque discursibus rupta, in longas flam- 
marum figuras dehiscebat ; fulgoribus ille et similes et majores 
erant.” 
The retreat of the sea, and its sudden return by the effect 
of the elasticity of the Said, seems to be one of the 
certained facts. 
Eruption of Fenrvius, 1730, ——— some Phil. Trans. 
* March 8th. Vesuvius mrs a ik a great smo ke ind etren 
evening, after eight o *clock, the fire arose to a vast height...... 
Pumice stones, red hot, of two or more ounces weight, were 
driven several miles like a shower of hail.” 
The blazing flame, hollow rumbling, throwing up of smoke, 
ashes, and st stone, are but Pon natural results already antici- 
pated. 
‘Collection 0 Share ers concerning Earthquakes felt in Eng- 
a. i afer Phil. Trans, vol. 46. 2 
ct ‘The mi gi get was felt preceels.s at  Cocpete potent 
