320 
Agricultural Meteorology. 
accompanied by any intimalion of the method by which he arrives 
at the results which appear above. By combining, however, the 
maximum monthly temperature given in one table with the 
minimum given in another, an atmospheric mean is obtained, 
different indeed from any presented by him. There remains the 
solar heat proper, of which the amounts respectively due to each 
month are stated. At first sight, it would appear intended that 
they should be added as they stand to the atmospheric range, in 
order to complete the quantities of caloric due to each source, 
but this operation gives far too high a figure ; at last, it occurred 
to the writer of this paper to divide the amount of solar heat, and 
strike out one-half, which might be considered as neutralized by 
the night. The following table shows the application of the 
calculation to Paris : — 
1. 
2. 
3. 
4. 
5. 
6. 
Mean hi^jliest 
Moutlily 
Temperaturp, 
from p. 77. 
Moan lowest 
Monthly 
Temperature, 
from p. 78. 
Mean, 
Monthly 
Temperature, 
deduced 
from the two 
preceding. 
Additional 
Solar Heat, 
from 
p. 77. 
Half 
tlie 
Solar Heat. 
Mean of 
Solar and 
Atmospheric, 
by adding 
Cols. 3 and 5. 
o 
o 
o 
O 
o 
o 
March , 
April 
May- 
June . 
July . 
10' 5 
15--2 
lS-6 
21-8 
23-4 
3-3 
7-8 
9-9 
12-9 
15-2 
6-9 
11-5 
14-2.5 
17-3 
19-3 
8-1 
8-6 
8-9 
4-2 
6 
4 
4-3 
4-45 
2 
3 
10-9 
15-8 
18- 7 
19- 3 
22-3 
The same method brings out the mean for Orange, as stated 
above ; and it is to be regretted that M. Gasparin should have 
printed his tables in so confused a form as to render it necessary 
almost to guess their import. 
These calculations, the author admits, will not apply to places 
situated under very distant parallels of latitude. 'I'hey are in- 
sufficient to explain how it is that the harvest takes place simul- 
taneously in Sweden and around London, the summer tempera- 
ture of London being \7 'V Centigr. (62* 78° Fahr.), and that of 
L^psal 15-1" Centigr. (59*18° Fahr.). So, too, at Lyngen, 
within the polar circle, in 70° N. lat., where, away from the sea 
winds, there are good corn harvests: although the snow only dis- 
appears so as to permit the seed to be sown on the 10th of June, 
yet there is then a whole month of continual daylight, a most 
efficient agent in stimulating maturity, the short northern summers 
being remarkably clear.* 
* Kaemplz and Pbiiillet establish, that vhen the sun is in the zenith 
only 70 to 80 per cent, of his rays reach the eaith ; and that the total 
number of rays that reach the f^round, in the course of any serene day 
even, is only half of what fall on the atmosphere. 
