164 
THE GEOLOGIST. 
one of water respectively heated to a given temperature, and then 
timed for the periods that elapsed in the giving out or radiation of 
the heat they had imbibed, for a reduction of ten degrees. These 
experiments we are so obtuse as not to see the corroborative force 
of, for it may be asked w hether, if it take five times as much heat 
to raise one body to the same temperature as the other, we might 
not expect to find one body proportionately longer than the other in 
parting with the heat it had obtained. It seems to us that the ex- 
periments would have been more to the purpose if a mass of molten 
lead had been covered by an iron-bottomed trough of water, in which 
a given mass of granite soldered down to the intervening iron plate 
had been partially immersed. Such, at any rate, would have been 
conditions more nearly resembling those presumed for our earth. 
Of course, the nebular hypothesis of the formation of stellar globes 
from the condensation of vaporous matter in space, and the evolution 
of light and heat in the process, was brought in as the primary origin 
of the presumed internal molten state of our earth ; but it will be 
well to bear in mind that our largest telescopes have resolved, one 
after the other, the numerous luminous patches in the vast heavens 
into gigantic clusters of sun-stars, and that up to this moment there 
is no proof whatever of any former nebulous state in our own or any 
other solar system. Nor was the oft-quoted nebular hypothesis the 
only support Dr. Trankland tried to get from astronomy. He has 
been searching the moon for more than a year with a reflecting tele- 
scope of 7 inches aperture, and has found two streaks on her surface, 
which he thinks may be the marks of glaciers with their terminal 
moraines. One of these fancied moraines is at the termination of 
that remarkable streak which commences near the base of the gigantic 
crater Tycho, through the ring of which it breaks, — a fact not omitted 
in Dr. Frankland's illustrating diagram, and which would alone much 
more naturally assign its origin to the class of volcanic phenomena. 
The other extends from Kheita, the crater-rim of which is also broken 
down, as it would be by the passage of a lava-stream. But as the 
author of the new hypothesis admits that, " with regard to the proba- 
bility of former glacial, or even aqueous, agency on the surface of the 
moon, difiiculties of an apparently very formidable character present 
themselves," we need not pursue further these lunar fancies — for 
such we cannot help regarding them. 
It will naturally occur to those who are not familiar with ice- 
making machines, that if warmer water in the sea will produce a 
