REVIEWS. 
VOLCANOES AND EARTHQUAKES.* — Professor Hunt has said more in the 
zones, or regions of the earth in which volcanoes are found most abund- 
antly, the author sums up the different theories which have been advanced 
in the endeavors to account for these phenomena. He rejects entirely, 
and with crushing force, the theory which attempts-to account for volca- 
noes by supposing that they are the vents of a liquid nucleus, and gives a 
summary of his reasons for doing so from which we quote the following 
paragraphs: 
we Judging from the known properties of the rocks icing which we are acquainted, solidifica- 
ti tl but at tł the liquid globe, a process which 
ould moreover be favored by the influence of pres This augments the melting temper- 
ware of makters, which, Hke me rocks and mort other solids, become less đense when melted, 
those which, like ice [or bismuth], be- 
me more rras by fusion. Pressure, moreover, it may be mentioned in this connection, in- 
eases ie t water for most bodies, whose solution may b scribed as a kind 
-* meltii nidos n with water into u Dese density is greater Agen that of the mean 
of its eonstituents; the importance of this Lees will appear farther he theory deduced 
rom the above considerations, and adopted by Hopkins and by elt ui id briefly as follows: 
the earth’s centre is solid, though still retaini ly the bigh temperature at which it be- 
À dnos At an advanced stage in tl lidi f fused 
r became viscid, so that the descent from the surface of the heavier partition, cooled by 
radiation, was prevented, and a didnt m rmed, gend tiep whieh s istas nar — gone on very 
slowly. There of yet unsolid- 
ified matter (or even api as suggested by Serope, a continuous Pn and ri is in the ex- 
istence of this stratum, or of lakes of uncongealed matter, that we are to find an explanation 
Y noes and earthquak t f the 
movemen whic h pen it "e >? rmation of moui pum in chain ns, as ingeniously set forth by Mr. 
Shaler. The utra a gradually a most important agency in the 
wer phones, is evidently not excluded by this hypothesis. It may be added that a sim- 
f the globe, viz., a solid nucleus and a solid crust separated from each other by 
hice stratum, wer io ng ago Suggested is Halley in order to explain the phenomena of ter; 
ism. 
poner or pressure m: esse portions ar of matter beneath th e surface to pass from solid tb 
liquid, or from a vires to a solid state, and in this way helps us to explain the local and the 
ys 
ede bavi of Hopkins and Serope appar ently 
which I adopt, though differing from it in some most important particulars, eines 
naming gisen them the existence of a solid nueleus and a solid erust, with an interposed 
, on o 
sss eous m dena but a layer of material which was once solid, but is now rendered liquid by the 
interve — ^a water under the influence of heat and pressure. When, in the process of re- 
iocus e globe bad r ached the pel int imagined by Hopki ns, where a solid crust was 
over the e shallow. v molten lay id , the farther cooling and 
contraction of ld lt in i ts, breaking it up, and causing the 
asatio: iiw the va liquid portions confined beneath. When at length the reduction of 
temperature permitted the precipita’ cpt T Te bp the — prasever — re, the 
whole eooling and disintegrating mass ken: 
* Abstract ofa Lecture by Profossor ' T: Lees ey enl D., ald R. S., delivered before the 
" Pamph., pp. 10. 
(118) 
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