J. Crol—Geological Climatology. 255. 
help to account for his inability to perceive how radiation from 
the ocean may heat the air more rapidly than radiation from 
the land, even though the surface of the latter may be at a 
higher temperature than that of the former. — 
He says: “The rapidity with which the heating process 
goes on depends on the difference of temperature, no matter 
whether the heat passes by conduction or by radiation.” This 
Statement will hardly harmonize with recent researches into 
vapor will not absorb the radiation of the land so rapidly as 
that of the ocean, for the ocean gives off that quality of rays 
Which aqueous vapor absorbs most rapidly. 
This is not in opposition to what I have stated in reason (1), 
for if the ground were transparent to the sun’s rays like 
water, evidently the total quantity of heat absorbed by it 
would be greater than that by the ocean. But radiation from 
the sun heats only the surface of the ground, all below the 
Surface depends for its supply on the slow process of conduc- 
‘on, whereas the ocean is heated by direct radiation to great 
depths, Consequently the total quantity of heat absorbed by 
® Ocean, say per square mile, in a given time, is greater t 
that by the land. 
