RESISTANCE BY LEAVES TO WATER LOSS 



23 



It becomes at once clear that the ranges of the ratios of relative 

 transpiration for plant 2 are in satisfactory agreement with that 

 of the index. The latter range is about 6 per cent smaller than 

 that of the relative transpii-ation ratio by the white instrument, 

 and about 11 per cent greater than that of the ratio by the brown 



TABLE 5 



HOUR 



Ratios op Relative Transpikation, Datura 



BY WHITE ATMOMETER 



BY BROWN .VTMOMETER 



Datura 1 



Datura 2 



Average 



Datura 1 



Datura 2 



Average 



(September 2) 















13 



Q X 



18 7 



14.1 



7 8 



15.7 



118 



X X . o 



14 



o . o 





11 .9 



6.8 



12.8 



Q 8 



15 



in 1 



17 9 

 X f . ^ 



13 .7 



9 2 



15.8 



19 



16 



7 



i . o 



in 8 



9. 1 



fi 4 



U . '± 



9.6 



8 n 



17 



7 9 



Q n 



8.1 



6.5 



8 1 



O . X 



7 3 



18 



"i fi 



O . D 



T n 



^ . o 



O . *J 



4 9 



A 9 



19 



1.7 



2.1 



1.9 



1.7 



2.2 



2.0 



20 



1.0 



10 



1.0 



1.0 



1.0 



10 



21 



2.1 



2.2 



2.2 



2 3 



2.5 



2.4 



99 



2.6 



3.0 



2.8 



2.9 



3 3 



3.1 



23 



2.2 



3.0 



2.6 



2.0 



2.9 



2 5 



24 



1.5 



2.2 



1.9 



1.6 



2.4 



2.0 



(September 3) 















1 



3.0 



3.2 



3.1 



3.2 



3 3 



3 3 



2 



5.0 



4.0 



4.5 



4 5 



3.7 



4.1 



3 



2.6 



2.4 



2.5 



2.4 



2.2 



2.3 



4 



4.8 



6.4 



5.6 



2.3 



3.1 



2.7 



5 



4.9 



4.0 



4.5 



4.5 



3.6 



4.1 



6 



5.7 



7.2 



6.5 



8.5 



10.8 



9.7 



7 



9.1 



11.3 



10.2 



6.5 



8.2 



7.4 



8 



9.6 



8.0 



. 8.8 



7.0 



5.8 



6.4 



9 



10.4 



8.0 



9.2 



8.2 



6.4 



7.3 



10 



11.3 



11.1 



11.2 



9 0 



9 0 



9 0 



11 



10.0 



6.0 



8.0 



8.4 



5.2 



6.8 



12 



11.5 



5.0 



8.3 



9.1 



4 0 



6 6 



13 



11.2 



4.8 



8.0 



9.1 



4 0 



6.6 



14- 



9.4 



4.0 



6.7 



7.8 



3 4 



5.6 



instrument. For the other plant the ranges are not in satisfactory 

 agreement, a state of affairs which is of course transmitted to the 

 averages for the two plants. It must be borne in mind that the 

 same plants were not used for the cobalt chloride tests and for 

 the transpiration determinations, and 'that it is possible that 



