162 
THE GEOLOGIST. 
bank's pole, the other extremity of which was held by infirm and 
trembling hands. His body might be put in proper attitude and 
position, and duly manoeuvred to acquire exactness of balance ; but 
if the shaky hands gave way, the fall might be sudden and severe. 
The supposed fire-origin of granite was one of the original causes 
of the invention of the internal-heat theory ; but modern researches 
have distinctly shown that certainly one at least of the petrological 
elements of that rock — namely, quartz — as seen now as a consti- 
tuent of that very granite, never could have been subjected to the 
influence of dry heat. Another diflSculty arises in respect to the 
internal molten state of our earth : if the core of our globe be in 
that condition, it would follow there must be internal tides, unless 
the solid crust of the earth were of immense thickness, and of a 
rigidity, at least, four times that of steel; for not less than that 
would suffice to resist the internal tidal tendency, taking the thick- 
ness of this crust as estimated by Mr. Ilopiiins. It is evident beyond 
question that a liquid mass, whether fluid at ordinary temperatures, 
such as the waters of the ocean, or rendered fluid by internal heat, 
must be equally subject to the laws of attraction ; and consequently 
the moon would have an influence upon the internal molten core, as 
she has upon the external oceans. 
!N"ow, Professor Frankland — repudiating all the explanatory theories 
which have been hitherto given to account for superficial diff'erences 
of temperature, from Lyell's different distribution of land and sea 
doctrine, to that of the higher elevation of all mountainous tracts 
during the Glacial age suggested by Professor Kamtz — based his 
new hypothesis on what he regarded as the incontrovertible fact of 
the internal molten fluidity of our earth. The descriptions of the 
fiords and the ice-scored land of Norway, which Dr. Frankland has 
lately visited, were exceedingly interesting and instructive; but 
when the Professor came to deliver his new hypothesis, we at once 
felt ourselves launched on the waves of an unnavigated sea, and saw 
many reasons why the bark of the adventurous savant should be 
deemed too frail for geologists to venture in. To say that the hypo- 
thesis was ingenious is only to give it its just meed of praise ; to say 
it was substantial is quite another thing. It was this : — We are all 
familiar with the ordinary still. There is the boiler where the vapour 
is raised, the spiral tube in which it is condensed, and the receiver 
into which the condensed fluid falls. Compare the earth, its atmo- 
sphere, and its mountains to. the still. Prom the ocean the vapour 
