WATER CONTENT OF PLANT PARTS. 47 
Since the manner of shading used in the transpiration method described 
above requires attention at least as often as every 10 minutes, it was not 
practicable to obtain both transpiration and water content readings on the 
same day, and in order to obtain the two sets of readings in comparable 
form the water content experiment was preceded and followed by transpi- 
ration readings, transpiration of branch f (see p. 31) being taken on Sep- 
tember 14, water content on September 15, and transpiration of branch g 
on September 16. No samples were taken from the limb from which came 
the branches used for transpiration. 
In order to obtain an approximation of the water content at the time 
corresponding to the transpiration readings, which it will be remembered 
were plotted to the middle of the time period, lines were dropped from the 
transpiration readings until they intersected the curves of water content 
TasLe 21.—Water content of leaves and their twigs. Experiment XIX. 
Series I. Series II. 
Date. Time. 
Leaves. | Twigs. | Leaves. | Twigs. 
1912. p.ct. p. ct. p.ct. p. ct. 
Sept. 14...} 900" p.m. 109.1 COQ ol aeencny mand 
Sept. 15...) 7 40 a.m. 102.4 TEA Tasers i 
8 45 a.m. 97.3 (Bat | -secease “4 
9 45 a.m. 98.2 SEM on tases bs 
10 45 a.m. 98.2 (i: (an ee a 
12 00 m. 101.1 74.4 103.0 74.4 
2 00 p.m. 102.7 78.2 102.0 72.2 
4 00 p.m. 105.1 S06) seas a 
5 30 p.m. 103.3 (es a 
Sept. 16...| 4 30 am, 109.4 HBe2 ‘| “eae 
r.20 qe | 
15 
arn: es hice ee See cm 2 T 
10 fe Aagre se let acere a cee Ora E 
05. f ee 
+00 Sane ee hig See 
Leaves PJ ee | es 
100 | | -|]--2 
P~ Ne see ie oe 
+ 95 i eae Qoser : 
+90 Water content 
r 85 j 
. La a 
19) Se ro akeiete IS Ne | ee ect ee 
Twigs bee Te Pe 
r70 eee a Ne I: ac 
65 
1. a 1 ai J 1 4 1 1 i. L 1 >a ey 
Tk = os 8 i a © 1 2 46 4 3 
Fig. 23.—Graph for moisture content of twigs and their leaves for September 15, 1912, 
plotted with relative transpiration for September 14 and 16, Exp. XIX. 
