AND OF PLANTS UPON THE ATMOSPHERE. 
171 
Experiment 11. 
Date. 
Circumstances of the experiment. 
Proportion 
per cent, of 
carbonic acid 
added. 
Absorption 
per cent, 
caused by 
solution of 
potash. 
Residuum 
per cent, 
after burning 
phosphorus 
in a portion 
of the air. 
Allowance 
for phospho- 
rus vapour. 
Calculate 
per ce 
nitrogen. 
amount 
at. of 
oxygen. 
Aug. 20. 
12 a. m. Bright day, with occasional 
clouds. Therm. 72°. Another Ce- 
dar like the former, with its pot, was 
introduced into a jar containing 
about 1300 cubic inches of air ; size 
of the plant being 8 inches in dia- 
meter, branches and all, and 16 
inches from the pot to the topmost 
branch 
7-50 
7-50 
79 
21 
10 P. M 
2-00 
80 
2 
78 
22 
Aug. 21. 
10 a. m. Windy day, often overcast. . 
1-75 
79-50 
2 
77-50 
22-50 
10§ A. M 
7-50 
9-25 
.... 
.... 
.... 
7 P.M 
.... 
5-00 
79-50 
2 
77-50 
22-50 
Aug. 22. 
11 a. m. Windy day, but with a 
bright sun 
2-50 
77-0 
2 
75-00 
25-00 
7 P.M 
0 
1-0 
75"5 
2 
73-5 
26-5 
Aug. 23. 
8 a. m. Windy and cloudy day, as 
above stated 
0 
1-0 
78-0 
2 
76 
24-0 
10 A. M 
7-5 
.... 
.... 
7 P.M 
0 
6-0 
75-25 
2 
73-25 
26-75 
Aug. 24. 
10 a. m. Cloudy day, without sun. . 
0 
5-0 
77-25 
2 
75-25 
24-75 
12 A. M 
2-5 
7-5 
.... 
7 P. M 
0 
6-0 
75-25 
2 
73-25 
26"75 
Experiment was here discontinued. 
Observations. — These two latter experiments tend to show that the leaves of evergreens purify the air as 
well as those of deciduous plants, although they may not act upon the carbonic acid with the same energy 
as the latter do. 
Experiment 12. 
May 27. 
Bright sunny day. Therm. 60°. Cras- 
sula lactea with its pot introduced 
into the jar at 12 a. m 
11 
11 
79 
21 
6 P. M 
0 
6-5 
81-25 
2 
79"25 
20-75 
May 28. 
8 a. m. Jar previously covered with 
a screen 
0 
6-0 
81-25 
2 
79-25 
20-75 
5 p.m. After a bright day 
0 
6-5 
80-00 
2 
78-00 
20-00 
Observations. — This experiment, and another made on another species of Crassula, show that these succu- 
lent plants do not act with much energy on the 
air, at least under confinement ; but the following experi- 
ment evinces that even this tribe act in the same manner, 
though not with the same intensity. 
Experiment 13. 
June 30. 
12 a. m. Plant of Mesembryanthemum 
verrucosum introduced into jar. 
(N.B. No record of the weather : 
probably it was fine) 
6-6 
.... 
.... 
.... 
79 
21 
8 P. M 
. 
4-9 
78 -6 
2 
76-6 
23-4 
July 1. 
10 A. M 
, , , , 
2-0 
.... 
.... 
.... 
10§ A. M 
4-5 
6-5 
— 
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