379 
Dioxide Absorption of Coco-nut Leaves. 
is not stated, because 0-0405 normal hydrochloric acid was used throughout. 
In Table IV, column 1 gives the hour at which each observation period 
ended. Each period was of one or two hours’ duration, and observations 
began at daylight, at 5.30 a.m., and continued until 6.30 p.m. in all except 
series 4, on May 24, which was begun at 5.50 a.m. and ended at 6.50 p.m. 
Columns 2 and 3 give the amounts of acid required to neutralize the barium 
hydroxide drawn from the Pettenkofer tubes of test apparatus and of 
control apparatus respectively. These are the final values for each test, and 
represent the most probable value of three titrations, at least two of which 
were identical in each case. Columns 4, 5, 6 , and 7 give data for the spread 
of two pinnae adjacent to the ones tested and on the same compound leaf. 
Each pinna was measured repeatedly at three marked points, and the 
average of the. six values thus obtained at each time of measurement is 
plotted as spread of pinnae on the graphs (Diagrams 2 to 6). Column 8, 
‘Weather conditions’, shows the observed sunlight condition during each 
day. The conditions are classified as bright, dull, or cloudy. Bright 
indicates full sunshine. Dull indicates that light clouds made the shadows 
cast by the sun dim but not entirely obscured. Cloudy indicates that 
heavy clouds obscured the sun. 
In Table V are shown the amount of carbon dioxide absorbed in 
grammes (col. 2) and the spread of the pinnae in centimetres (col. 3), 
both computed from Table IV. There are also included such data from 
weather instruments as were available for the days in question. 
Table IV. 
Titration results from tests of carbon dioxide absorption by leaves of 
a young coco-nut tree, May 16 to 28, 1918. 
Series 2. — Two pinnae of leaf 2, 574-32 sq. cm. Tested on May 16. 
Hour of 
removal 
from ap- 
paratus. 
Acid required to 
neutralize 2 V07 c.c. 
of Ba{OH\. 
Time 
measured. 
Spread of lower edges 
of adjacent pinnae. 
Weather conditions . 
Test. 
Control. 
A.M. 
c.c. 
c.c. 
cm. 
cm. 
cm. 
5.40 
1-70 
2-0 
2.30 
5.45, sun up. 
6.^o 
1.40 
1.50 
1. So 
6.30 
19.85 
19.40 
1.60 
1.70 
2.05 
6.10, sunlight on leaf. 
Bright sunlight all day. 
835 
1.30 
I.30 
1.60 
8.30 
20.35 
19.40 
i -35 
I.50 
1.70 
>> 
1. 10 
I-IO 
1-25 
10.30 
20.10 
19.50 
10.30 
1.20 
1.30 
i*6o 
1. 10 
*. C.90 
1.05 
P.M. 
12.30 
19-90 
19.50 
12 30 
1.0 
1.05 
i -45 
>5 
0.90 
c-Po 
1.0 
2.30 
20.15 
19.40 
2 30 
0-90 
1*0 
1.50 
>> 
0.90 
6.90 
1.0 
4.30 
20.05 
19-55 
4-30 
1.10 
1-20 
i -55 
?> 
1. 10 
1-0 
c.85 
6.30 
20.10 
19.65 
6.30 
1.30 
1 .60 
1.90 
6.25, sun down. 
1.15 
I. IO 
1.40 
C c 
