1900 - 190 ].] Prof. Knott on Solar Radiation . 
311 
Table showing the time in hours reckoned from culmination at 
which for given values of the sun’s declination , as shown in the 
top row , the radiation crossing unit horizontal surface at the 
equator has value as shown in the first column. 
JR. 
23° 27' 
20° 
12° 
0° 
Sun’s 
declination. 
0-7 
0 ) 
•679 
0 
•643 
0 
•622 
0 
•606 
0*77 
1*12 
1*55 
1*68 
hours 
•512 
1-98 
2*11 
2*34 
2*46 
k measured 
•421 
2*69 
from cul- 
•331 
3*27 
3*35 
3*48 
3*54 
mination. 
•249 
3-79 
•091 
473 
476 
4*81 
4-83 
•06 
4*94 
*007 
5-47 
5*49 
5*51 
5*52 
/ 
Declination. 
Half-daily heat- 
ing (relative). 
+ 23° 27' 
122*9 
+ 20 
127*4 
+ 12 
135-2 
0 
139-2 
-12 
135-2 
-20 
127-4 
-23 27 
122-9 
1 
Earth Thermometers at the equator would, of course, show no 
annual period ; and the semi-annual period would penetrate to a 
comparatively small depth. 
