Teavees. — On the former Wannthin 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 jpressure 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 -j-L of 

 what steam ought to weigh, supposing water could exist as a perfectly 

 gaseous body at 32° under a pressure of 30 inches of mercury. Hence the 

 molecules of aqueous vapour at 32° must be five or six times farther 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 increase 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 hquid and even in 

 the solid form, though feeble, is not anniliilated, and that hence, when the 

 atmosphere surrounding water or even ice is dry, the superficial molecules 

 of the water or ice assume then- self-repulsive character, and fly off until 

 the surrounding atmosphere is saturated. The quantity of vapour which 



