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



301 



ficient length of branch in which transverse diffusion of the 

 current may be effected. In other words the current can flow 

 across the branch if the obliquity of flow imposed on it is slight. 



The following experiments bear on this point : 



Exp. 30. Portugal laurel. Aug. 14, 1885. 



The first incision I. was at 11 cm. from the cut end. Incisions 

 Nos. II., III., IV., V., VI. were then made successively at distances 

 of 10, 8, 0, 4, 2 cm. from I., as shown in the diagram, Fig. 0. The 

 incisions were 7 mm. deep, the branch being 13 — 14mm. in diameter. 



Time 



11. B0 

 54 

 57 



Sawed 



12.1 



6 



15 



Sawed 



21 

 30 

 35 



Sawed 



39 

 55 



Sawed 



58 

 1.36 



4.8 



Sawed 



4.13 

 35 



Sawed 



4.45 I 



Rate 



2f> 

 27 



27 



at i, 



24 

 25 

 25 



at II, 



13 

 17 

 17 



at in, 



17 

 18 



at iv, 



17 

 18 

 19 



at v, 



16 

 17 



at vi, 



about 5 5 



We see that when the branch was sawn on the side opposite to 

 the first cut, even though at 10 cm. distance, a considerable depres- 

 sion occurred. That is to say, a considerable depression was caused 

 by the current being forced to travel obliquely. The depression was 

 not markedly increased until the obliquity of transmission was 

 greatly increased by sawing at 2 cm. from the first cut. 



