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REVIEWS OF NEW PUBLICATIONS. 
quent paragraph. They are intermittent thermal springs. First, water is thrown 
up from the volcanic bowels of the earth to a great height; and when the fluid 
is exhausted, steam continues to ascend for some time. The well-known phre¬ 
nologist, Sir G. Stuart Mackenzie, Bart., has propounded a highly ingenious 
and probable explanation of these gushing fountains. Iceland may be considered 
almost exclusively one mass of volcanic matter. Now water percolating from 
the surface of the earth through various crevices, is quickly converted into steam 
by the burning lava below. Heated steam, rising from beneath the basin of 
water in the rock, becomes partially condensed ; water filling the lower part of 
the cavity attains the boiling temperature, while steam under high pressure 
occupies the upper portion of the chasm. The expansive power of the steam rises 
until it propels the water through a fissure or pipe in the rock, and a great dis¬ 
tance through the open air. When the water :*■ exhausted the steam escapes, as 
previously explained. 
In a former number we stated that horizontal sedimentary strata have fre¬ 
quently been raised into mountains by sudden volcanic eruptions; but it has 
been shown, by means of the pyrometer, that the central heat of the earth acts in 
another way to produce the same effect. The expansion of a bar of metal by 
heat, and its subsequent contraction on cooling, are facts familiar to the chemist ; 
and Col. Totten has proved, by careful experiments on granite, marble, &c., that 
the expansion or contraction of large masses of these substances from variations of 
temperature, would account for the elevation and subsidence of extensive tracts of 
country (p. 81). An interesting and remarkable instance of this, apparently 
resulting from the above-mentioned cause, is afforded by the celebrated remains of 
the temple of Jupiter Serapis, at Puteoli, an engraving of which, from L yell’s 
Principles of Geology , is supplied by Dr. Mantell. Such changes, it appears, 
have been taking place from the earliest ages, and are still in operation in our 
times. Thus the tract of country in Scandinavia, lying between Frederickshal, 
in Sweden, and Abo, in Finland, or even further, is slowly and visibly rising; 
while on the other hand, the adjacent coast of Greenland is gradually sinking.— 
This fact was noticed long ago by Celsius, and has recently been confirmed by 
Mr. Lyell. Here, observes Dr. Mantell, is u an instance in which the eleva¬ 
tion of a country, with the whole burden of its people and its cities,, is actually 
taking place, unheeded by the busy multitude, and known only by the researches 
of the natural philosopher!” —p 92. 
Further on, the singular circumstance is noticed of |entire animals, bones, flesh, 
and skin, having been found in frozen gravel and in ice-bergs. 
“In 1774, near Vilhoui, the carcase of a Rhinoceros was taken from the frozen sand, where it 
must have been concealed for ages, the soil of that region being always frozen to within a few 
inches of the surface. The carcase was a complete natural mummy, part of the skin being still 
covered with long hairs, and forming a warmer covering than that of the African Rhinoceros.—- 
