104 Kansas Academy of Science. 



red 1.9, yellow 2.66. green 4, blue 10.40, a cloudy day, starch 

 formed in two hours and fifty minutes. 



Later a few spring rains fell, and the new leaves which opened 

 out were of a much lighter green than the old ones. When the 

 'temperature was 20 deg. C, and the light readings were, red 19, 

 yellow 20, green 20, blue 56.06, it was found that it took one hour 

 and thirty minutes to form starch in the old leaves, and two hours 

 and thirty minutes in the young leaves. 



Comparisons of the amount of light used in the two cases were 

 as follows: Amount of light coming to the plant was, red, 19; 

 yellow, 20; green, 20; blue, 53.06. 



Amount of light which passed through dark leaf was, red, 

 0.1384; yellow, 0. 2647; green, 0.6; blue, none. Amount of light 

 which passed through colorless leaf was, red, 7.826 ; yellow, 0.9; 

 green, 18.5 ; blue, 3. 



The amount of light reflected from the two leaves was the same 

 in each case, and was as follows : Red, 0.5538 ; yellow, 1.125 ; green, 

 1.5; blue, L154. 



Hence, from these figures, we get the amount of light used by . 

 each leaf in making starch as follows : 



Dark" green Yellow 



leaf. new leaf. 



Red 18.3076 10.602 



Yellow 18.6103 17.955 



Green 17.9 



Blue 51.906 48.906 



Some experiments were performed to determine at what time in 

 the night the starch left the plant. On the morning of April 14, it 

 having turned cool in the night, the temperature dropped to 10 

 deg. C. At seven o'clock the leaves showed starch around the 

 sieve-tubes ; none in the palisade cells. 



April 28 leaves taken every hour during the night were examined. 

 Starch grew gradually less after midnight. It was nearly all gone 

 at four o'clock ; all gone at 5 : 15. Temperature, 20° C. 



April 29 leaves picked every hour were examined. There was a 

 gradual decrease of starch after midnight, and at five o'clock no 

 starch was left. Temperature, average, 20° C. 



On the morning of the 12th of June similar experiments were 

 made. Although the temperature was much higher at this time, 

 the starch remained later in the leaves, because of the greater 

 abundance the evening before. The leaves examined in April 

 showed scattered grains of starch, while those examined in June 

 showed starch in thick masses crowdinar all the cells. 



