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 whether, 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. Erankland 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 Rheita, 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, difficulties 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 



