LAWS OF HEAT. AIR. 97 



near the equator, would produce steam of greater 

 elasticity, rarity, and temperature, than that 

 which occupies the regions further polewards; 

 and such steam, as it came in contact with the 

 colder vapour of a higher latitude, would be 

 precipitated into the form of water. Hence 

 there would be a perpetual current of steam 

 from the equatorial parts towards each pole, 

 which would be condensed, would fall to the 

 surface, and flow back to the equator in the form 

 of fluid. We should have a circulation which 

 might be regarded as a species of regulated dis- 

 tillation.* On a globe so constituted, the sky of 

 the equatorial zone would be perpetually cloud- 

 less ; but in all other latitudes we should have an 

 uninterrupted shroud of clouds, fogs, rains, and, 

 near the poles, a continual fall of snow. This 

 would be balanced by a constant flow of the cur- 

 rents of the ocean from each pole towards the 

 equator. We should have an excessive circula- 

 tion of moisture, but no sunshine, and probably 

 only minute changes in the intensity and appear- 

 ances of one eternal drizzle or shower. 



It is plain that this state of things would but 

 ill answer the ends of vegetable and animal life : 

 so that even if the lungs of animals and the 

 leaves of plants were so constructed as to breathe 

 steam instead of air, an atmosphere of unmixed 



* Daniell. Meteor. Ess. p. 56. 

 W. 5 H 



