~ 
LOCAI, DISTRIBUTION OF SPECIES. 45 
tioned were placed in galvanized-iron tubes and sunk in the earth so that 
the sensitive bulb was 1 foot below the surface of the ground, the space 
above it being filled with a plug of earth, also inclosed in a galvanized- 
iron tube, so as to secure readings representing as closely as possible the 
temperatures at that depth. They were also placed, during a portion of 
the period of observation, with the bulb an inch below the surface. The 
ordinary soil thermometers were placed so that the bulbs were 2 inches 
below the surface. Two of these were employed, one in full light and 
the other in shade, at each station. The black-bulb thermometers were 
placed with the bulb 1 to 2 inches above ground, and readings were taken 
in full sunlight and in shade at each station. The Weather Bureau 
maximum and minimum thermometers were set up for comparison at 
each station, each being artificially shaded. 
The readings taken during the period of observation are too volumi- 
nous for record here, but are given in part, on p. 98, in the section on 
climatic conditions. Only the more important results will be given in this 
place. 
(1) Minimum and maximum soil thermometers, bulb at depth of 1 foot: 
(a) During the period of observations in December the average mini- 
mum and maximum were, for station I, 54° and 57° F. and for station 
II, 49° and 49.5° F.; that is, the minimum at station I, averaged 5° and 
the maximum 7.5° higher than at station II.! 
(6) In May, during the period of observation, the average minimum 
and maximum for station I were 74.5° and 80° F., and for station II 
70.5° and 73° F.; the minimum at station I averaged 4° and the maxi- 
mum 7° F. higher than at station II. 
(c) The difference between minimum and maximum at station I was 
from 2° to 3.5° F. in December, and from 4° to 7° F. in May, while for 
station II the corresponding differences were 0.5° in December and 1° 
to 4° in May. 
(2) Minimum and maximum soil thermometers, bulb at depth of 1 
inch below the surface. The observations recorded in March, April, and 
May, table 7, with the bulb 1 inch below the surface, show, as would be 
expected, a far wider range of temperature. 
(a) The average minimum and maximum at station I were 62.5° and 
95° F., and at station II 60° and 70° F. 
(6) The difference between minimum and maximum readings at station 
-I ranged from 30° (March 29) to 40° F. (March 25). At station II the 
difference ranged from 6.5° (April 12) to 13° F. (March 29). 
(c) While the minimum at station I averaged only 2.5° higher than 
at station II, the maximum averaged 25° F. higher. 



1Slight apparent discrepancies in these averages are due to the fact that they are 
derived from a larger number of temperature records than are given in tables 8 to 10, 
p..98. 
