ABOUT TERRESTRIAL TEMPERATURE. 85 
80° =A+B+:217C 
69°-5=A+B cos” 30°+:395 C cos 60° 
42°°7=A+B cos” 50°+°53 C cos 100° 
15°°7=A+B cos” 70°+°395 C cos 140° 
where it is to be remarked that the numerical co-efficient of the last term is not 
the fraction expressing the land on the precise parallel, but the mean of three values 
of the land (graduated by an interpolating curve) extending over a space +10° on 
either side of the given parallel. This seems to give a truer expression of the 
climate of the parallel.* I call this factor L’. 
33. These equations being solved (m being found by approximation) we have 
very nearly— 
T, =12°5 + 59°-2 cos ¢ 4+ 38°1 L’ cos 2a 
From this we readily deduce what the equatoreal and polar temperatures would 
be, 1st, of a globe covered entirely with water ; 2d, of a globe entirely of land— 
All Water. All Land. 
Equatoreal Temperature (A=0°) . 71°°7 Fahr. 109°8 Fahr. 
At Latitude 45° 5LoOe SLO» 5. 
Polar Temperature G90"). 12h, —25°6 ,, 
§ IV. Confirmation of the Hypothesis and Formula. 
34. The preceding calculations are founded upon the configuration and climate 
of the NortHERN HemispHere alone. I think it important to add, that they were 
actually made without any anticipation of how they might apply to cases not con- 
templated in the construction of the formula. The following table shows the 
* Thus treated, the numbers of Table II., par. 22, give the following results :— 





L L’/ 
Latitude. Proportion of Land Mean of 3 values L’ cos 2a 
by Equalizing Curve. from ~—10° to ~a4+10° 
Woo oNt 29 302 — 260 
Oe “48 395 — 303 
65 ,, s6c ‘46 — 295 
60 ,, 58 “52 — 260 
50; 55 D3 —‘092 
40 ,, “47 “473 +:082 
30 ,, “40 395 +:197 
20 ,, 32 318 +°244 
LOR: 24 252 +:237 
Oo “21 217 +:217 
—10 8. 22 21 +:197 
—20 ,, 22 ‘ 205 +°157 
—30 ,, 18 16 +:080 
—40 ,, 07 085 +015 

