446 REVIFAVS OF NKW PUBLICATIONS. 



quent par-agraph. 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 rilling 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 is 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 Lyell'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 Frcdenekshal, 

 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 " 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, tlie 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.— 



