Biological Papers. 



101 



Following is a statement of some of the experiments. The angle 

 of the leaf was measured by means of a goniometer used for de- 

 termining the height of trees. The light strength was determined 

 by means of a light machine invented by Professor Stevens, of the 

 State University, who took a large number of the readings recorded. 



Experiineiits made on a plant in a loindow : 



Experiment No. 1. 



Temperature, 20° C. Time, 1:30 to 2:00 P. M. 



Light readings: Red, 0.372; blue, 0.328; green, 0.89. 



Leaf No. 1. Leaf No. 2. 



Dropped 37° 46° and 60° 



Rose 5° 17° 



Experiment No. 2. 



Temperature, 21' C. Time, 1:00 to 3:00 P. M. 



Light readings: Red, 0.605; green, 2.94; blue, 6.432. 



25 

 35 

 30 

 20 

 20 

 20 



Experiment No. 3. 



Temperature, 22 C. Time, April 3, 8:25 A. M. 



Light readings: Red, 0.3477; green, 1.404; blue, 3.65. 



Leaf No. 1. Leaf No. 2. 



Time, 60 minutes 13 30° 



Petiole of leaf twisted. 

 Time, 30 minntes 18° 20° 



Experiment No. 4. 



Temperature, 17° C. Time, April 4, 8:55 A. M. 



Light readings: Red, 0.295; green, 1; blue, 7.628. 



Leaf No. 1. Leaf No. 2. Leaf No. 3. 



Time, 35 minutes 20' drop. 20° 6° 



30 " 13° , " 12° 9° 



Experiments made on a plant in the field (the leaves were turned 

 to the west, because a box had been placed over the plant): 



Experiment No. 1. 



Temperature, 18° C. Time, April 26, 8:35 A. M. 



Light readings: Red, 8.33; green, 22.75; blue, 43.73; yellow, 13.16. 



Leaf rose 8°, fell 18°; stem moved 15° in 15 minutes. 



