The Effect of Light on the Transpiration of Leaves. 291 



Experiment 21. — June 6, 1913. P. laurocerasus. 

 9.30 a.m. — Cut a shoot with nine leaves of current year and fitted to 

 potometer after vaselining and cutting. At east window. Dull day. 

 -i/r 59-62 per cent. 



Time. 



E. 



Time. 



E. 



10.34 a.m. 



61 -0 







10.37 „ 



98 -5 



11.42 A.M. 



In dark room. 



10.52 „ 



81 -3 



11.48 „ 



41 -9 





(lighter) 



12.3 p.m. 



44-8 



11.15 „ 



69 -0 



12.20 „ 



37 7 



11.40 „ 



54 -3 



12.38 „ 



29 -3 



Eesult : L/D = 185/100. 



Experiment 22. — June 7, 1913. P. laurocerasus. 

 10 A.M. — Young shoots, six leaves. At east window. Dull day. ip- 62- 

 74 per cent. 



Time. E. 



Time. 



E. 



10.15 a.m. 49 -5 

 10.25 „ 48 -0 

 10.51 „ 75 -0 

 11.7 „ 66-7 

 11.22 „ 59 -4 

 11.30 „ 58 8 



11.39 A.M. 



| 11.52 „ 

 12.12 P.M. 

 12.24 „ 



Placed in dark room. 

 49-8 

 48 -0 

 40-1 

 38-3 



Eesult : L/D = 154/100. 



Experiment 23. — June 12, 1913. P. laurocerasus. 

 11.50 a.m. — Young shoot, seven leaves, vaselined but no incisions made. 

 ^ 52-63 per cent. T 17'9-20-3. 



Time. 



E. 



Time. 



E. 



June 13, 1913. 





11.7 A.M. 



107 -0 



9.30 A.M. 



Fresh surface to branch 



11.13 „ 



97 -4 





cut under water: 



11.25 „ 



88 -7 



9.50 „ 



25 -8 



11.39 „ 



87-8 



10.0 „ 



24 -3 



11.48 „ 



89 -2 



10.1 „ 



Cut leaves, i.e. usual 



11.54 „ 



89 -9 





incisions made. 



11.55 „ 



Eeplaced at east window. 



10.6 „ 



69 -6 



12.2 p.m. 



85 -5 



10.10 „ 



85 -5 



12.12 „ 



99 -8 



10.36 „ 



109-0 



12.29 „ 



96 -9 



10.42 „ 



113 6 



12.38 „ 



105-0 



10.47 „ 



113 -6 



12.47 „ 



105-0 



10.55 „ 



117 -6 



12.50 „ 



108 -0 



10.56 „ 



Placed in dark room. 







Eesult : Light 131, Dark 100, Light 120. Average : L/D = 126/100. 



