292 



Sir F. Darwin. 



Experiment 24. — June 13, 1913. P. laurocerasus. 



June 13, 1913. — A shoot with nine leaves, none very young ; vaselined 

 June 14, 10.5 a.m. At east window, yfr 63-61 per cent. T 18-4-20° C. 



Time. 



R. 



Time. 



R. 



10.19 A.M. 



23 -9 



11.32 A.M. 



128 



10.24 „ 



26 -5 



11.38 '„ ' 



131 



10.26 „ 



Cut up leaves. 



11.47 „ 



126 



10.28 „ 



95 2 



11.56 „ 



129 



10.34 ,, 



126-6 



12.11 P.M. 



118 



10.37 „ 



140 



12.12 „ 



Replaced at east window. 



10.50 „ 



150 



12.18 „ 



128 



11.3 „ 



160 



12.23 „ 



137 



11.10 „ 



154 



12.30 „ 



138 



11.15 „ 



156 



12.36 „ 



134 



11.16 „ 



Placed in dark room. 



12.52 „ 



140 



11.23 „ 



144 







Result : — 



Light 132, Dark 100, Light 119. Avera 



ge : L/D = 126/100. 



Experiment 25. — June 16, 1913. P. laurocerasus. 



Shoot with seven leaves, none very young. Vaselined and placed at east 

 window. 



Time. 



R. 



Time. 



R. 



June 17, 1913. 



Cut fresh surface to 



10.36 a.m. 



102 -0 



branch under water 



10.45 „ 



105 -0 



9.35 a.m. 



Placed at east window. • 



11.4 „ 



105 -0 





\f' 56-66 per cent. 



11.5 



Placed in dark room. 





T 21 -9-25 8 



11.21 „ 



75 -3 



9.59 „ 



19 -8 



11.30 „ 



76 -1 



10.0 „ 



Cut up the leaves 



11.42 „ 



78 -6 



10.4 „ 



67 -1 



11.50 „ 



76-7 



10.10 „ 



95 -5 



11.52 „ 



Replaced at east window. 



10.14 „ 



105 -0 



12.23 p.m. 



106 -0 



10.23 „ 



109 3 



12.33 „ 



106 



10.30 „ 



103 -0 







Result 



Light 138, Dark 100, Light 137. Average : 



L/D = 138/100. 



Weighing Experiments (Laurel). 



In a few experiments the transpiration was estimated by the loss 

 of weight of a cut branch (laurel) in a bottle of water covered with a layer 

 of olive oil. The branches had each six leaves, which were carefully 

 vaselined and cut in the usual way. The stem and all buds also vaselined 

 with care. 



