1885.] On the transpiration-stream in cut brandies. 



347 



If the result be graphically represented, it will be seen that 

 the incisions make practically no difference in the gradual fall per- 

 ceptible in the rate of absorption. 



In another experiment the results were as follows: 



The first cut produced no slowing, but a slight quickening of 

 the rate. The second cut produced a slowing represented by 100 

 to 91-5. 



Lastly, in another experiment the amount of slowing was 

 100 to 96. 



The following is an abstract of the above potometer experi- 

 ments. The figures given represent the amount of slowing 

 produced by double sawing. The rate before sawing being taken 

 as 100*. 



Portugal laurel 1 00 to 8 -2 



20-8 



6-2 



13-4 



4-4 



6-6 



28-6 



15-9 



Pinus sylvestris. 



Beech 



Ivy 



Sycamore 1 1 "7 



33-0 



Elder 



H. Chestnut 



5-0 



38-0 



18-3 



1-6 



1-7 



Average 100 to 142 



Helianthns tuberosus 



100 to 16-1 



Taxus baccata 



100 to 96 



50-8 



50 



33 



72-8 



95-5 

 89-2 

 91-5 

 96-0 



Average 100 to 74-9 



Average of trees ex- ) 

 eluding Helianthus ) 



The different results obtained, in most cases, with Gymnosperms 

 as compared with Angiosperms will be discussed later on. 



Effects of double sawing estimated by iveights of water 

 absorbed. 



The following experiments were made with the view of con- 

 firming by another method the experiments made with the poto- 

 meter. The branches were fixed with their cut ends in water, and 

 the amounts of water absorbed in a given time were estimated by 

 weighing the vessels at regular intervals. The branches were then 



* Where the rate increased after the first cut owing to the air becoming drier, 

 tfce. &c, the rate after the first cut is taken as 100. 



VOL. V. PT. V. 24 



