Agricultural and Forest Meteorology. Go 
Locality. 
Elevation. 
PercentujjL' "f 
possible I'ffcct 
of Sun's rays 
actually 
nct'lvod. 
Summit of Mont Blanc . . 
15,781 
94 
10,007 
89 
Glacier des Bossons .. 
4,000 
79 
700 
71 
These figures show us that the lowest 15,000 feet of the 
earth's atmosphere absorb at midday one quarter of the useful 
heating effects of the sun's rays, and explain to us why the 
heat is found so oppressive in mountain ascents. 
The expression "sums of temperature" calls for some ex- 
planation ; in this resolution it evidently means the total amount 
of heat received during the day, but there is another use of the 
phrase, which was first employed by Boussingault, when he 
calculated the total amount of heat required to ripen various 
crops ; stating, for instance, that wheat required 8248° Fahr., 
from the time it began to grow in spring, for the proper 
ripening of the seed. It is, however, as yet undecided whether 
this amount of heat is to be determined from the daily mean 
temperature or the daily maximum temperature, and on this 
point further investigation is desirable. 
E. 8. " The temperature of the soil should be measured at least at four 
levels between the surface and the depth of one yard, and the experiments 
should be conducted in various soils, and with various kinds of crops, &c. 
"This investigation most properly belnngs to scientific agriculturists and 
forest officials, and to technical experimental stations." 
Earth temperature is a subject to which too little attention 
has as yet been paid in England generally, but the Scottish Me- 
teorological Society has for many years published such returns, 
and two very valuable and interesting papers from the pen of 
Mr. Buchan " On the Temperature of the Soil compared with 
that of the Air," have been printed in that Society's ' Journal ' 
(vol. ii. p. 273, and iii. p. 211). 
K. 9. " Observations on the occurrence of frosts are particularly desirable. 
The best mode of registering these observations in a form useful for practical 
discussions is a subject well worth study. 
"Of course minimum thermometers are to be employed, but only such as 
have the bulb quite clear of the frame." 
The registration of the occurrence of frosts hardly calls for 
remark, but there are several points of interest as to the 
limitation of the damage done to certain parts of a farm, such 
