J. Croul—Geological Climatology. 257 
in getting rid of its heat, the mean temperature of equilibrium of 
the ocean must be higher than that of the land; consequently 
the mean temperature of the ocean, and also of the air imme- 
diately over it, in tropical regions should be higher than the mean 
temperature of the land and the air over it.’ 
Since the publication of ‘Climate and Time,’ the accuracy 
of this conclusion has been confirmed in a remarkable manner 
from recent researches on the actual mean temperature of the 
two hemispheres, the details of which have been given by Mr. 
Ferrel in his ‘ Meteorological Researches,’ Washington, 1877. 
It is found that the mean temperature of the northern or land 
hemisphere is higher than that of the southern or water hemis- 
phere up only to about latitude 35°, and that beyond this 
latitude the mean temperature of the water hemisphere is the 
greater of. the two. At latitude 40° the mean temperature of 
the southern hemisphere is 1°-4 higher than that of the same 
parallel on the northern hemisphere. At latitude 50° the 
difference amounts to 4° ‘4, while at latitude 60° the mean tem- 
perature of the southern hemisphere is actually 6° higher than 
that of the northern on the same parallel, The mean tem- 
peratures of the two hemispheres are as follows : 
Lat., O72 ARP 00? i BB gn MO OO 4 G0? | 10% 908 
Northern, 80°-1 81°0 77°°6 67°76 5675 43°4 2973 14°4 4°5 
Southern,. 80°1 78°% 74°71 66°-7 B7°9 478 35°3 1... -... 
Heat cut off by the Atmosphere.—Professor Newcomb says 
further ; “Another idea of the author which calls for explana- 
Hon is that solar heat absorbed by the atmosphere is entirely 
lost, 86 far as warming any region of the globe is concerned. 
- 218 18 no idea of mine. ‘My idea is not that the heat cut oft 
'$ entirely lost but merely that the greater part is lost. A 
ge portion of the heat is reflected, and of that absorbed one- 
