20 
Journal of Agricultural Research 
Vol. XXVI, No. I 
that they are seldom detected even by the galvanometer. Some data 
in regard to the fluctuation of the temperatures of the air and of leaves 
are shown in Tables II and III, and are illustrated by graphs in figures 
2 and 3. 
Table II .—Fluctuations in the temperature of the air and of the leaves of wilted and 
turgid cowpeas from 1.15 to J.30 p. m. on July 28, IQ22, as recorded by twenty ob¬ 
servations * 
Air. 
Wilted 
leaves. 
Turgid 
leaves. 
Air. 
Wilted 
leaves. 
Turgid 
leaves. 
°C. 
°c. 
° c . 
°C. 
°c. 
° c . 
36.0 
41.3 
35- 1 
35- 5 
42. 5 
35*4 
35-9 
43- 0 
35- 0 
35- 8 
42.3 
35- 2 
35- 5 
4i. 5 
34- S 
35- 2 
40. 0 
35- 0 
37-o 
45-o 
37- 5 
35-4 
40. 0 
34- 6 
37-o 
46. 0 
3 6 - 5 
35- 7 
40. 8 
35- 2 
36. 7 
43- 5 
3 6 -4 
35- 2 
40. 1 
35-° 
34- 7 
4i- 5 
35-8 
35- 5 
4°- 5 
35-3 
35- 0 
41. 2 
35* 0 
36.0 
42. 0 
35-6 
35-3 
42. 0 
33- 6 
37-o 
42. 0 
36- S 
3-5-o 
41-3 
35- 0 
37- 5 
43-o 
36. 7 
1 The sky was clear and a brisk breeze was blowing. 
Table III .—Showing the slight fluctuations of the temperature of the air and of the leaves 
of plants during periods when the air is still 
JULY 26, 
8.20to 8.30 p. 1H; 
JULY 26,10.30 to 10.40 p.m. 
Air. 
Cowpea 
leaves. 
Pumpkin 
leaves. 
Air. 
Water¬ 
melon 
leaves. 
Sudan 
grass 
leaves. 
°C. 
° c . 
°C. 
°c. 
° c . 
°c. 
22. 9 
22. 9 
22. 7 
22. 2 
22.3 
22. 2 
22. 9 
22. 8 
22. 7 
22. 2 
22. 0 
22. I 
22. 9 
22. 8 
22. 6 
22. I 
22. 0 
22. O 
22. 8 
22. 6 
22. 5 
22. I 
22. 0 
22. I 
22. 9 
22. 6 
22. 5 
1 22. 2 
22. 2 
22. 2 
22. 7 
22. 4 
22. 4 
22.3 
22. 2 
22. 2 
22. 7 
22. 4 
22. 4 
22. I 
22.1 
22. I 
22. 6 
22.3 
22.3 
22. 2 
22. 2 
22. I 
22. 6 
22.3 
22.3 
22. O 
22. 0 
22. O 
22. 6 
22.3 
22.3 
22. I 
22. 0 
22. I 
JULY 26,10.10 to 10.20p. m. 
JULY 27 , 
12.20 to 12.30a. m. 
21. 8 
22. O 
21-5 
23. I 
23.1 
2 3 * 3 
21. 8 
21. 6 
2I.S 
23. I 
23. 1 
23-4 
21. 8 
21. 8 
21. 6 
23. 2 
23. 2 
23. I 
21. 8 
21. 8 
21. 6 
2 3 * 1 
23. 1 
23-4 
21. 7 
21. 8 
21. 6 
23. 1 
23. 0 
23. I 
21. 8 
21. 8 
21*5 
2 3 - 1 
23.1 
2 3. I 
21. 6 
21. 7 
21. 5 
23. 2 
23.1 
23. I 
21. 7 
21. 8 
2i- 5 
23. 1 
23.1 
23. I 
21. 6 
21. 6 
21. 5 
23. 1 
23. 1 
23. I 
21. 6 
21. 6 
21.4 
23. 1 
23. 1 
23. I 
