438 Vines . — The Suction-force of 
In the first place, the enquiry may be made as to the 
relation between the bulk of a shoot, as a whole, and its 
suction-force ; and for the purposes of such an enquiry the 
following data, referring to four different branches of Beech, 
are available : — 
Branch. 
A. 
B. 
C. 
D . 
Length of main shoot . 
0 
7 ft. 
5 ft. 
6 ft. 
5 ft. 
Diameter of cut surface 
• 
1 in. 
1 in. 
\ in. 
h in- 
Number of leaves 
• 
1150 
320 
755 
594 
Maximum tension observed . 
• 
2i£ in. 
Hi in- 
i6| in. 
23 in. 
Gas-bubbles evolved at tension of 
21J in. 
11 in. 
11 in. 
12 in. 
Now the e bulk ’ of a shoot includes the important factor of 
the leaf-area, a factor which might well be thought to be 
preponderant. But a consideration of the foregoing figures 
shows that no definite relation can be traced between the 
leaf-area of the four branches and their suction-force. This 
remarkable fact comes out even more strikingly when the 
leaf-area of one and the same branch is diminished at intervals 
by the removal of some of the leaves, as follows (the letters 
refer to the branches already mentioned) : — 
Shoot A. 
Time. 
No. of 
Indicator 
No. of leaves 
leaves. 
travelled. 
retnoved. 
June 5. 
n.io-noon 
1150 
0-2 1 J in. max. 
( 330 ) 
12.10-1.5 p.m. . 
. 820 
0-20 „ 
77 
(270) 
1.20-2.35 . 
55 ° 
0-18I „ 
77 
( 195 ) 
2.45-3.40 . 
355 
0-20 „ 
77 
(no) 
3.50-5.4° . 
245 
0-18J „ 
77 
June 6. 
10.35 a.m.-i 2.50 p.m. 2 45 
°-2°| „ 
77 
( 245 ) 
1. 10-3. 5c p.m. . 
. leafless stem 
°~44 55 
77 
Shoot B . 
June 9. 
1-4.30 p.m. . . 320 
°-! 3 f 
)> 
(81) 
„ 11. 
11.45 a-m.-6.15 p.m. . 239 
°~9 l 2 
V 
(94) 
„ 12. 
12.15 p.m. -5 p.m. . 145 
8I-12J 
>> 
}> 
(102) 
v I 5 * 
3.50 p.m. -5 p.m. . 43 
0_ 5 l 
}) 
