3900-1901.] Prof. Knott on Solar Radiation. 
307 
Month. 
October, . 
November, 
December, 
January, . 
February, . 
March, 
April, 
May, 
June, 
July, 
August, . 
September, 
Accumulation of 
Heat per sq. cm. 
of Surface. 
{ 
I 
{ 
f 
\ 
910 
754 
604 
452 
296 
183 
107 
55 
18 
3 
0 
27 
87 
245 
330 
520 
719 
909 
1041 
1128 
1189 
1212 
1161 
1045 
From these numbers we learn that in the beginning of Sep- 
tember there are some 1200 more units of heat under each square 
centimetre of the Calton Hill than in the beginning of March. 
It remains now to compare this accumulation of heat with the 
amount of energy supplied by solar radiation. To this end we 
must make for the latitude of Edinburgh the same kind of cal- 
culation as was made for the latitude of the Mediterranean in the 
first part of this paper. The results are given in the following 
table, drawn up similarly to that on page 299. 
