278 Natural History of Volcanos and Earthquakes. 
We shall endeavor to show in our next section what effect 
_ might be expected on the surface of the earth, if its solid crust 
should still continue to increase in thickness towards the interior 
by gradual consolidation of the fluid centre. Besides, I think 
that a sinking of the outer crust can scarcely be supposed to 
occur, but that it is much more probable that caverns should be 
formed at the moment when the fluid mass becomes solid. At 
least the latter effect was seen in fusing two basalt balls, two feet 
in diameter, in which many larger and smaller cavities were 
found. I shall allude to these phenomena in another section. 
If we take into consideration all that has been already said on 
ejections and elevations, (sowlevémens,) we shall be induced to 
adopt the following inferences. Masses of our earth, still in @ 
fluid state, may be raised through and above its solid crust. The 
rising of the lava in the craters of volcanos is a satisfactory proof 
of this circumstance. Solid rocky masses, strongly heated, may 
be pushed upwards during violent convulsions, and elevations of 
the original rocky covering, or be thrown up in the form of loose 
masses, more or less heated. The not unfrequent rising of small 
islands from the bottom of the sea, and the elevations (sowléve- 
mens ) actually observed to take place in the continents, are evi- 
dences of these operations. All these phenomena are effects of 
forces, which develope their whole intensity in a very short time, 
often ina few moments. But large islands, and even whole coun- 
tries may, in a very short time, be raised several feet, as was 
shown in the cases of Chili and Santa Maria. On the other 
hand, Scandinavia presents us with an instance of an elevation 
which, compared with the preceding, takes place with extraordi- 
nary slowness. 
Besides all these elevations which have been actually observed; 
other appearances occur, which lead us to infer that elevations 
have taken place previous to the existence of any record. e 
are the elevations of old volcanic masses, as basalt, trachyte, he, 
their penetration into fissures, and the elevation of whole systems 
of mountains. In regard to the first, the conclusion may, 2S has 
been already shown, be considered as well founded as it is ge" 
erally possible to be, when drawn from phenomena which have 
taken place before any records were in existence. The similarity 
between these phenomena, and those which have taken, and st 
take place, before our eyes, render it extremely probable that they 
