Travers.—On the former Warmth in high Northern Latitudes. 463 
origin as a mass of diffused cosmical matter, condensed into a planetary 
mass by the natural gravitation of its particles, such condensation resulting 
in the generation of heat sufficient to reduce the whole mass to a molten 
condition. But no sooner had this mass been completely formed, than it 
began to cool at the surface, by the radiation of its heat into space, and the 
surface must then have presented the peculiar aspect described by the 
authors referred to, as that exhibited by the surface of a pot of molten metal 
drawn from a melting furnace. But, as the process of cooling continued, a 
definite thickness of the surface would pass from the fluid into the solid 
condition, undergoing, whilst doing so, that expansion which is observed to 
take place immediately upon solidification, and causing, by such expansion, 
and the subsequent contraction which accompanies the cooling of a solid 
body, great irregularities upon the surface of that globe. During this first 
period the heat radiated would be sufficient to maintain, in a highly rarefied 
state, all the elements of our atmosphere, including aqueous vapour. But 
when this cooling had proceeded until the heat of the surface of the crust 
had been reduced to a point below the boiling point of water at the then 
rate of atmospheric pressure, the aqueous vapour would be condensed upon 
that surface in the form of water, which would gradually increase in 
quantity until the cooling had proceeded far enough to admit of the existence 
of life. We know that the divellent energies common to ordinary gaseous 
bodies, are even more conspicuous in bodies which assume the gaseous form 
at high temperatures. Thus water under the ordinary pressure of our 
atmosphere becomes thoroughly a gas only when heated to 212°, and retains 
this gaseous form, within certain limits, above its boiling point. But below 
212° the case is different, the elastic force of aqueous vapour (as steam is 
more properly termed below 212°) rapidly diminishes, so that at 82° (the 
freezing point of water) its elastic force is found to be scarcely equal to one- 
fifth of an inch of mercury, and a given volume to weigh only ly of 
what steam ought to weigh, supposing water could exist as a perfectly 
gaseous body at 82° under a pressure of 80 inches of mercury. Hence the 
molecules of aqueous vapour at 82° must be five or six times further apart 
than in the perfectly gaseous form of steam, and so feeble in their repulsive 
force that, even when thus separated, the aqueous molecules cannot be 
approximated by slight ineréase of cold or of pressure without partial co- 
alescence and the formation of water or ice. But we are told that the self- 
repulsive force exerted by the molecules of water in the liquid and even in 
the solid form, though feeble, is not annihilated, and that hence, when the 
atmosphere surrounding water or even ice is dry, the superficial molecules 
of the water or ice assume their self-repulsive character, and fly off until 
the surrounding atmosphere is saturated. The quantity of vapour which 
