294 



Sir F. Darwin. 



Experiment 28.— May 24, 1913. P. laurocerams. 77-88 per cent. 



T 15-1-18-5 C. 







Loss. 



Time. 











Per hour. 



Corrected for \f. 



9.34 a.m. \ 

 10.27 „ J 

 10.27 „ \ 

 11.44 „ J 



Light. 

 Dark. 



grm. 

 328 



0-129 



290 

 153 



11.44 „ \ 

 3.59 „ J 



Light. 



0-321 



273 



3.59 „ 1 

 5.0 „ J 

 5.0 „ I 

 6.48 „ | 



Dark. 

 Light. 



0-195 

 0-217 



163 

 217 



Average : L/D = 245/158 = 155/100. 

 Or, omitting the last L period : L/D = 325/162, or 201/100. 



Experiment 29. — May 25. P. laurocerams. -ty 76-83 per cent. T 17"8-20-5. 



Time. 





Rate. 



Corrected for \p. 



9.26 a.m. "1 

 10.38 „ J 

 10.38 „ 1 

 11.44 „ ) 

 11.44 „ 1 

 12.51 „ J 



Light 

 Dark 

 Light 



231 

 155 

 264 



231 

 162 

 264 



12.5 L „ 1 

 4.10 „ J 



Light 



257 



236 



Average : L/D = 244/162 = 151/100. 



The results of the series of four weighings are : — 

 L/D = 159/100 ; 134/100; 201/100; 151/100. Average L/D = 161/100. 



Experiments on Ivy (Hedera helix). — July, 1913. 



In the following experiments by Miss Pertz the specimens were cut at 

 night and placed in water, and on the following morning a fresh surface was 

 cut under water. 



The leaves and stems were then carefully vaselined and four incisions 

 per leaf were made. 



In all cases the transpiration rate is corrected for ty. 



