The Effect of Light on the Transpiration of Leaves. 293 



The experiments took place in the laboratory above referred to, in which 

 darkness was not absolute. 



The specimens weighed from 100 to 130 grm., and were only weighed to 

 within 5 mgrm. 



Experiment 26. — May 10, 1913. P. laurocerasus. 

 8.52 A.M.— At bright north light, f 71-88 per cent. T 11-13-6° C. 









Loss. 



Time. 











Per hour. 



Corrected for v//. 



9.37 a.m. I 

 10.21 „ J 



Light 



grm. 

 0-252 



219 



10.32 „ \ 

 11.21 „ ; 



11.21 „ 1 

 12.3 P.M. J 



Dark 

 Light 



0-114 

 180 



127 

 167 



12.3 „ I 



1.3 „ ; 



Dark 



0-107 



122 



1.3 „ I 

 1.59 „ J 

 2.0 „ 1 



3.3 „ J 



Light 

 Dark 



0-244 

 0-113 



217 



(sky very bright.) 

 129 



Kesult, average L/D - 



= 201/126 = 159/100. 



Experiment 27. — May 22, 1913. P. laurocerasus. 

 Leaves vaselined, but not incised until May 23. 

 May 23.— Light clouds. ^ 75-86 per cent. T 14-2-18-2° C. 







Loss 



Time. 











Per hour. 



Corrected for >p. 



9.44 A.M. \ 

 10.43 „ J 

 10.47 „ i 



n.52 „ ; 



Light 

 Dark 



grm. 

 0-249 



0-134 



271 

 167 



11.52 „ 1 

 12.44 p.m. J 



Light 



0-294 



254 



12.44 „ \ 

 1.44 „ J 



Dark 



0-250 



208 



1.44 „ 1 

 2.51 „ J 



Light 



0-242 



242 



2.52 „ \ 

 4.15 „ J 



Dark 



0-236 



197 



Average : L/D = 



256/191 = 134/100. 



