86 PROFESSOR FORBES’ INQUIRIES 
results of a comparison of the approximate formula (33) with M. Dove’s tables 
for other northern latitudes than those used in constructing it; and also for the 
southern hemisphere, so far as trustworthy observations extend. Latitudes be- 
yond 75° north cannot be made use of in consequence of our ignorance of the 
distribution of land and water in those regions. 
Tasxe III. 
Values from Formula. 
Latitude. Temp. Observation. Theory. Difference. 
Ail Land. All Water. 



75° North —9°6 23°°4 
70 
65 
—1°6 28 -0 
60 37 ° 
50 46° 
40 54 
61- 
67 
70 
71 
70 
67 
61 


4 
‘6 
8 
7) 
‘5 
8 
‘O 
“9 
y 
‘0 
Cte sap at eo OG) dak. of ..G, ke Jol 
So SG-eyOo © & Fk oo a ko wor 
pS ate a 8 ao S mh oC 
OA) ean & -w- Ow o. ik 

54 


35. I will not now direct attention to the numbers for the northern hemisphere, 
which may not be thought to coincide better than (or, perhaps, even as well as) 
might have been anticipated from the range of latitudes used in deducing the for- 
mula. But the general close coincidence of the observed with the calculated tem- 
peratures in the southern hemisphere offers a confirmation of a very different kind. 
36. The lower temperature of the southern hemisphere up to lat. 40°, compared to 
the northern, has often and justly been attributed tothe diminishing amount of land, 
as the higher temperature of a parallel some degrees north of the equator, than 
that of the equator itself, is due to the increasing amount of continental surface, 
especially in Africa. Our formula gives a precise expression to these generalities. 
And the fidelity of the formula (at least for the lower latitudes) is proved by the 
