278 



Sir F. Darwin. 



60 



I i " 



1 i i 



50 



■ 





40 





/ 



30 







20 







10 







. / 







I I — I ' I 1 



110 100 90 80 70 60 50 



Fig. 7 (Experiment 7). 



Experiment 8. — April 22, 1912. P. laurocerasus. Fig. 8. Apparatus fitted 



up in the Dark Eoom. 



Time. 



Period. 



Rate. 



T. 



<f<. 









°C. 



per cent. 



10.45 a.m. 



i 



22 -4 



17 -3 



60 



to 11.30 „ 





(average) 







11.32 „ 



Bell jar over plant; supported on blocks 25 mm. high. 



11.56 ., 



ii 



15-1 



17 -8 



74 



12.8 „ 



Blocks reduced to 2 mm. 







12.14 p.m. 



iii 



12-7 



18 -0 



77 



12.24 „ 



iv 



10 7 



18-0 



84 



12.32 „ 



V 



8-0 



18 -1 



88 



12.37 „ 



vi 



7-8 



18 -1 



88 



12.44 „ 



vii 



6-5 



18 -1 



91 



12.54 „ 



viii 



5 -3 



18 2 



93 



12.59 „ 



ix 



5-0 



18 -2 



94 



2.15 „ 



X 



3-5 



18 -2 



97 



2.29 ., 



xi 



3-3 



18 -3 



98 



20 



10 



Fig. 8 (Experiment 8). 



The general characteristics of the illustrations above given are 

 (1) The points which represent the transpiration for different degrees of 

 relative humidity are roughly in a straight line — from which it follows that 

 a definite relation of some sort exists between transpiration and relative 



