^8 Journal of Agricultural Research voi. x, No. i 



in the leaves of the three plants occurs in the most cases between 2 and 

 5 p. m. The average difference between the minimum and maximum 

 amount of dry matter in the leaves during the day was 4.0, 4.8, and 8.0 

 gm. for com, kafir, and milo, respectively. 



The minimum amount of dry matter in the leaves of corn during 10 

 nights from 7 p. m. to 7 a. m.- occurred 8 times at 5 a. m., once at mid- 

 night, and once at 3 a. m., while the leaves of milo in the same number 

 of experiments reached their minimum dry-matter content 7 times at 5 

 a. m., twice at 7 a. m., and once at 7 p. m. During the 8 nights that the 

 leaves of kafir were examined, the minimum amount of dry matter 

 occurred at 5 a. m. in all cases. Sunrise occurred about 5 a. m. at the 

 time of these experiments. 



The average difference between the maximum and minimum amount 

 of dry matter per square meter of leaf during the night periods was 5.3, 

 5.2 and 6.3 gm., respectively, for the com, kafir, and milo. 



The maximum amount of dry matter in the leaves of corn during the 

 night occurred 7 times at 7 p. m., twice at 9 p. m., and once at 11 p. m. 

 The leaves of milo during the same number of periods reached the maxi- 

 mum amount of dry matter 7 times at 7 p. m., twice at 1 1 p. m., and once 

 at 9 p. m. In 8 night experiments with kafir the dry matter in the 

 leaves was the highest 5 times at 7 p. m., twice at 9 p. m., and once at 1 1 

 p. m. The average variation of dry matter from the minimum amount 

 in the leaves at night to the maximum amount in the leaves during the 

 day was 6.2, 6.0, and 7.7 gm. per square meter of leaf for com, kafir, and 

 milo, respectively. 



Several cases were noted where a marked increase in the dry matter of 

 the leaves occurred for one or more 2-hour periods during the night. On 

 August 10, 1 914, the dry matter decreased in the leaves of all three of 

 the plants from 5 to 9 p. m. During the next 2-hour period the dry mat- 

 ter in the leaves of corn increased from 46.9 to 48.6 gm. per square meter 

 of leaf, while in the same time an equal area of kafir leaf increased in 

 dry weight from 50.9 to 51.9 gm. From 9 p. m. to 11 p. m. the dry 

 matter in the leaves of milo increased 1.6 gm. per square meter of leaf 

 and showed no signs of depletion until i a. m. On August 15, 1914, the 

 dry matter in the leaves increased 3.5, 1.7, and 2.8 gm. per square meter 

 of leaf, respectively, for com, kafir, and milo between 7 and 9 p. m. On 

 August 25, 1914, the dry matter in the leaves of com dropped from 54.3 

 gm. per square meter at 5 p. m. to 51.9 gm. at 7 p. m., and then increased 

 the next two periods to 53.7 gm. at 11 p. m. The' kafir leaves decreased 

 in dry matter per square meter from 60.4 gm. at 5 p. m. to 58.7 gm. at 

 7 p. m., and then gradually increased during the next two periods to 61.3 

 gm. at 1 1 p. m. After 11 p. m. the dry matter in the leaves of both corn 

 and kafir began to decrease. The dry matter in the milo leaves de- 

 creased 2.6 gm. per square meter of leaf surface from 5 to 7 p. m. During 



