The Effect of Light on the Transpiration of Leaves. . 295 



Experiment 30.— July 1, 1913. Ivy. 



10.20 A.M. — Shoot with seven leaves vaselined, no incisions made. 

 July 2, 9.30 a.m. — In potometer at east window. Dull. During the day 

 day f 60-70 per cent. T 1 8-19 6° C. 



Time. 





Average. 



Time. 



E. 



Average. 



9.38 a.m. 



27-8 





10.43 a.m. 



77 -0 







9.41 „ 



27-8 





10.53 „ 



71 -9 







9.43 „ 



Cut up leaves with scalpel, 



11.4 „ 



78 -2 









4 cuts each leaf. 



11.11 „ 



74-6 1 





76 



9.47 „ 



75 -8 





11.18 „ 



76-9 J 





9.51 „ 



82 -0 





11.19 „ 



Replaced at east 



window. 



10.0 „ 



96 -2 





11.22 „ 



75 -8 







10.17 „ 



91 -3 





11.27 „ 



82 -0 







10.26 „ 



112 -0 



. 



12.43 p.m. 



91 -0 







10.32 „ 



124 -0 1 



115 



12.46 „ 



91 -0 1 





95 



10.35 „ 



106 -0 J 



12.52 „ 



99-0 ; 





10.35 „ 



Placed in dar 



c room. 











L. D. L. 



Result 115 76 95 Average : L/D = 138/100. 



or 151 100 125 



Experiment 31. — July 4, 1913. Ivy. 

 11 a.m. — Shoot, 12 leaves, cut and vaselined. 



July 5, 10 A.M. — In potometer at east window, yjr during day 63-68 per- 

 cent. T 16-7-18-4 C. 



Time. 



10.15 A.M 

 10.19 

 10.22 



10.25 

 10.31 

 10.41 

 10.52 

 11.1 

 11.9 

 11.11 

 11.12 



R. 



Average. 



Time. 



Average. 



32 -0 

 29 -7 



Cut up leaves with scalpel, 



4 cuts each leaf 



108-0 



122 -0 



126 -0 



137 -0 



139 -0 



147 -0 



147 -0 

 Placed in dark room 



147 



11.17 A.M. 

 11.40 „ 

 11.51 „ 

 11.59 „ 

 12.0 

 12.8 

 12.18 

 12.33 

 12.42 

 12.47 

 12.51 

 12.53 



NOON 

 P.M. 



103 



121 

 106 

 102 -0 

 104 -0 



Replaced at east window. 

 115 -0 

 123 -0 

 125 -0 

 127 -0 

 123 -0 

 131 -0 

 134 -0 



133 



Result 

 or 



147 

 143 



D. 



103 



100 



L. 



133 

 129 



Average : L/D = 136/100. 



