438 
Journal of Agricultural Research 
Vol. XXXI, No. 5 
Table IV .—Interior temperatures of the date palm compared with air and soil 
temperatures of corresponding hours , April 21 to April 27 
Time 
Air 
Soil 
at 2 
feet 
Zaheedy 
(by 
ther¬ 
mome¬ 
ter 1 ) 
Zaheedy 
(by 
ther¬ 
mome¬ 
ter 2 ) 
Rela¬ 
tive 
hu¬ 
midity 
Time . 
Apr. 21: 
°F. 
°F 
0 F. 
o F 
P. ct. 
Apr. 24—Con. 
6.30 a. m- 
«49 
__ 
b 77.00 
74.00 
27 
4.45 p. m_. 
10.00 a. m_ 
75 
70.00 
74.50 
74.00 
5.45 p. m_- 
11.00 a. m. 
82 
74.00 
73.00 
6.15 p. m__ 
12.15 p. m. 
87 
73.50 
72.00 
7.35 p. m_. 
2.40 p. m. 
92 
69.90 
72.50 
71.50 
8.30 p. m.. 
5.30 p. m_ 
92 
72.00 
72.00 
23 
9.30 p. m_. 
6.45 p. m_ 
88 
_ 
72.50 
72.50 
Apr. 25: 
8.20 p. m_ 
74 
_ 
74.50 
74.75 
6.30 a. m_. 
9.00 p. rri- 
70 
75.00 
75.00 
7.40 a. m . 
10.00 p. m. 
75 
75.00 
75.00 
8.55 a. m._ 
&pr. 22 : 
9.45 a. m__ 
6.20 a. m. 
58 
69.90 
77.25 
75.00 
10.45 a. m.. 
9.00 a. m_ 
82 
75.50 
74.75 
11.45 a. m _ 
10.15 a. m. 
86 
75.00 
74.50 
23 
12.30 p. m__ 
11.00 a. m. 
88 
75.00 
73. 50 
1.30 p. m 
12.00 a. m_ 
90 
70.00 
74.50 
72.50 
2.45 p. m-_ 
1.30 p. m. 
93 
_ 
74.25 
72.25 
3.45 p. m__ 
3.00 p. m. 
95 
73.50 
72.00 
4.30 p. m 
4.00 p. ill- 
95 
— 
73.00 
72.00 
6.30 p. m_ 
5.00 p. m. 
90 
76.66 
73.00 
72.00 
18 
7.30 p. m_ 
7.15 p. m. 
84 
74.50 
73.75 
8.30 p. mu. 
8.10 p. m. 
79 
75.50 
74.00 
9.30 p. m_ 
9.15 p. m. 
78 
76.50 
74.00 
Apr. 26: 
10.00 p. m. 
77 
77.00 
74.50 
* 6.30 a. m._ 
Apr. 23: 
8.00 a. m._ 
6.15 a. m- 
53 
70.00 
78.00 
77.50 
9.00 a. m.. 
7.05 a. m. 
57 
79.00 
77.50 
57 
10.00 a. m.. 
8.15 a. mu 
72 
77. SO 
77.98 
11.30 a. m__ 
9.30 a. m. 
74 
77.50 
77. 10 
1.30 p. m._ 
10.45 a. mu 
83 
77.00 
76.30 
3.00 p. m._ 
11.25 a. m. 
85 
76.90 
76.00 
4.10 p. m._ 
12.30 p. rri. 
87 
70.00 
76.50 
75.20 
5.00 p. m__ 
1.45 p. m. 
92 
_ 
75.50 
73.40 
7.00 p. m_. 
2.30 p. nu 
H 
75.00 
72.20 
8.30 p. m__ 
3.40 p. m. 
92 
75.00 
72.10 
9.30 p. mu. 
4.20 p. m. 
90 
75.00 
72.10 
23 
10.30 p. m__ 
5.30 p. m. 
87 
75.00 
72.30 
Apr. 27: 
6.30 p. m_ 
82 
70. 50 
75.75 
73.00 
6.30 a. m_. 
7.30 p. m. 
77 
76.50 
75.10 
8.10 a. m_ 
8.30 p. m. 
73 
77.30 
76.00 
9.40 a. mu 
9.30 p. nu 
71 
78.00 
76.50 
10.30 a. m_. 
Apr. 24? 
11.30 a. m._ 
6.30 a. m. 
61 
70.50 
79.50 
' 77.00 
v 
12.35 p. m._ 
7.30 a. m. 
65 
79.00 
7 7.50 
59 
1.45 p. m_- 
8.10 a. in. 
68 
78.90 
76.90 
2.35 p. m__ 
9.30 a. mu 
73 
78.40 
76.30 
3.40 p. m_. 
10.25 a. m_ 
77 
78.10 
75.90 
4.30 p. m_- 
11.30 a. m 
80 
77.20 
74.40 
5.30 p. m__ 
12.45 p. m. 
85 
76.10 
73.80 
6.30 p. m_. 
1.30 p. m 
88 
76.00 
73.20 
8.30 p. Hi-- 
2.30 p. m_ 
92 
75.50 
73.00 
9.30 p. m__ 
3.20 p. m_ 
91 
75.00 
73.00 
Air 
Soil 
at 2 
feet 
Zaheedy 
(by 
ther¬ 
mome¬ 
ter 1 ) 
Zaheedy 
(by 
ther¬ 
mome¬ 
ter 2 ) 
Rela¬ 
tive 
hu¬ 
midity 
1 
°F. 
°F. 
°F 
°F. 
P. ct. 
90* 
74.60 
73.*00 
28 
86 
74.98 
73.75 
84 
74.90. 
73.50 
77 
_ 
75.20 
73.50 
74 
76.00 
71 
70.75 
77.60 
76.00 
63 
71.00 
79.00 
77.00 
67 
78.10 
76.30 
72 
77.50 
75.45 
18 
74 
77.00 
75.50 
78 
76.50 
75.50 
79 
76.25 
75.00 
82 
71.00 
76.00 
74.50 
87 
75.60 
74.00 
90 
75.00 
74.00 
87 
74.50 
73.50 
85 
74.00 
74.00 
37 
78 
71.00 
75.25 
74.50 
74 
76.00 
75.00 
71 
77.00 
75.80 
70 
77.50 
76.00 
64 
71.00 
77.00 
76.00 
66 
77.00 
76.00 
70 
77.00 
75.60 
56 
73 
76.50 
75.25 
81 
75.50 
74.75 
85 
75.00 
72.95 
90 
74.50 
72.50 
87 
74.00 
72.95 
85 
73. 75 
73.40 
32 
■ 75 
71.25" 
74.50 
74.30 
72 
76.00 
72 
77.00 
75.20 
71 
— 
77 .10 
75.20 
65 
71. 25 
79.00 
76.10 
70 
78.40 
75. 38 
57 
78 
71.40 
77.80 
74. 75 
82 
76.75 
74.30 
84 
75.90 
72. 50 
86 
71.50 
75.95 
71.60 
90 
75.80 
71.42 
92 
75.80 
71.60 
98 
71. 50 
75.00 
71.60 
92 
74.95 
71.68 
90 
74.95 
71.60 
20 
86 
74.95 
71.60 
78 
71.00 
76.00 
72.50 
74 
76. 75 
73.40 
a Figures in bold-face type indicate lowest temperature for the day. 
b Figures in italic indicate highest temperature for the day. 
Table V shows the records of the Maktoom tree at the growth 
center and of the Zaheedy tree at 2 feet from the ground, from 
April 28 to May 4, a period when the interior temperature curves 
both fell mainly below the curve of the mean daily air temperature. 
Table VI shows temperatures observed in May, 1923, in the trunk 
of a large seedling male palm at 4 feet from the ground, compared 
with soil temperatures at 2 feet and 3 feet deep. Here, with an 
older and more deeply rooted tree, a striking proof of the influence 
of the ascending sap current is introduced, in that the tree trunk 
temperature passed below that of the soil at 2 feet for several days, 
and closely approached the soil temperature given by the thermom¬ 
eter set at a depth of 3 feet. 
