140 Report oF THE DIRECTOR OF THE 
observations at 6 p. m., but at depths of three inches and more 
the 6 p. m. observations are the highest of the day, and this is 
true whatever the month of observation. 
It will be seen, also, that at depths of 18 and 24 inches the 
temperatures are constant throughout the day, and this which- 
ever month is considered. 
While the general daily average of all the monte is nearly 
the same for is depth, it is found that there is a general 
increase, though slight, in the temperatures as we compare the 
greater with the less depths. 
If we compare the average monthly temperatures for the 
months April to October, inclusive, of the air with the soil 
thermometers of different depths we find an interesting and 
important fact indicated as follows: 



| | Average air | Average soil - 
thermometer. | thermometer, 
| 
=) 
® 
oq 
4% 
% 
if] 
o 
i 
For seven months.....,..... LrIneee ots 4 2.3 
BGrinix MONTHS as , cone hia 9 inches *:..,.. 58.7 60.3 
Horfive months)? {.ho4 4k 3 chest: pan 58.8 60.2 
Hortwo months). eae fe Orinchesese. 55.4 57.4 
Fortwo monthsyi..6 6. « veh i) Ounehesi neers 55.4 57.2 
Hor three months: j:).c6eeee 12 inches ..... 60.0 62.4 
EEO UNTER MOULOS.. 1 ce Ace es Pps unches svcrs 60.0 64.0 
Pomtwo months: ..<socck. | 24 inches ..... 55.4 65.0 


The excess of temperature after a depth of three inches was 
found in the months of August, September and October, thus 
showing that in the latter portion of the season a large reserve 
of heat has been stored up in the soil, modifying greatly the 
severity of the winter and permitting probably a root develop- 
ment which otherwise could not go on at the lower temperature 
of the air. 
