44 Journal of Agricultural Research voi. x, no. i 



any desired length of time. From the results thus obtained, the amount 

 of water and dry matter for each square meter of leaf, the percentage of 

 water on a wet basis, and the percentage of water on a dry basis were 

 calculated. 



The amount of water in the leaves of milo was found to be much lower 

 at all times of the day and night than that of either com or kafir leaves 

 at a Hke stage of development, while the average water content of the 

 com and kafir leaves at the same age was practically the same. The 

 water content of the leaves of corn, kafir, and milo averaged 118.5, 

 120.0, and 107.0 gm., respectively, for each square meter of leaf during 

 the day periods and, taken in the same order, 127.9, 132.7, and 115.5 gm. 

 for the night periods. The average variation per square meter of leaf 

 between the water content of the leaves during the day and night was 

 9.4 gm. for com, 12.7 gm. for kafir, and 8.5 gm. for milo. The average 

 variation between the maximum and minimum water content of the 

 leaves from 7 a. m. to 7 p. m. was 13.8, 8.4, and 7.8 gm. for each square 

 meter of leaf respectively for com, kafir, and milo, while the average 

 range between the maximum water content of the leaves during the 

 night and the minimum amount during the day was 23.8 gm. for com, 

 25.9 gm. for kafir, and 21.7 gm. for milo 



During the 22 days the evaporation as measured by a Livingston 

 porous-cup atmometer reached a maximum 18 times between 2 and 3 

 p. m. and 4 times between 3 and 5 p. m. In two-thirds of the observa- 

 tions for com and milo and in nine-tenths of the observations for kafir 

 the minimum water content of the leaves under the conditions of these 

 experiments occurred from two to four hours earlier than did the maxi- 

 mum evaporation as measured by the porous-cup atmometers. For the 

 rest of the observations the minimum amount of leaf water occurred at 

 the time of maximum evaporation. 



The average variation between the maximum and minimum percentage 

 of water in the leaves on a wet basis during the day from 7 a. m. to 7 p. m. 

 was 3.5 for corn, 3.2 for kafir, and 4.5 for milo. On the same basis the 

 average variation between the minimum percentage of water during the 

 day and the maximum percentage during the night was 5.4, 5.9, and 6.0, 

 respectively, for corn, kafir, and milo. The average difference between 

 the minimum and maximum percentage of water on a dry basis during 

 the day from 7 a. m. to 7 p. m. was 39.5 for corn, 31.1 for kafir, and 35.9 

 for milo. The average range between the maximum and minimum water 

 content on this basis during the night from 7 p. m. to 7 a. m. was 37.5, 

 47.5, and 40.0, respectively, for com, kafir, and milo, while the average 

 range between the minimum percentage of water on this basis during the 

 day and the maximum percentage at night was 67.8 for com, 67.2 for 

 kafir, and 51.2 for milo. 



