AND OF PLANTS UPON THE ATMOSPHERE. 
169 
Experiment 7- 
Circumstances of the experiment. 
Proportion 
per cent, of 
Absorption 
per cent, 
caused by 
Residuum 
per cent, 
after burning 
Allowance 
for pbospho- 
Calculated amount 
per cent, of 
Date. 
carbonic acid 
solution of 
phosphorus 
rus vapour. 
added. 
potash. 
in a portion 
of the air. 
nitrogen. 
oxygen. 
May 11. 
11 a.m. Dull and sultry day. Fresh 
Geranium introduced 
8-5 
8-5 
81 
2 
79 
21. 
11 P. M 
0 
1 
81 
2 
79 
2! 
Observations. — These two latter experiments show decidedly that the disappearance of carbonic acid is 
not at all in proportion to the disengagement of oxygen. 
In Experiment 6, in 
a bright sun, the Geranium, 
which absorbed 9'5 per cent, of carbonic acid. 
emitted 5 
per cent, of oxygen 
; in Experiment 7. 
a similar 
plant, which absorbed 7'5 of the former in a dull day, seemed to have made no 
addition at all to the amount 
of oxygen in the jar. 
Experiment 8. 
May 13. 
2 p. m. Bright sunshine all the day. 
A young Lilac {Syringa vulgaris ) 
had its stem introduced under the 
jar, its roots being in a pot outside 
8 
8 
81 
2 
79 
21 
7| P. M 
0 
0-05 
82-5 
2 
80-5 
19 
May 14. 
8 A. M 
0 
6-00 
not esti 
mated. 
8^. Day as that preceding it 
2 
8 
8 P. M 
0 
2 
75-5 
2 
73-5 
26-5 
May 15. 
9 a. m. Jar during the preceding part 
of themoming coveredwith ascreen 
0 
3-5 
76-0 
2 
74 
26-0 
9| A. M 
65 
io-o 
2 P. M 
0 
3-0 
72-25 
2 
70-25 
29-75 
85 P. M 
0 
00 
72-00 
2 
70-00 
30-00 
May 16. 
8 a. m. Jar during the former part 
of the morning having been covered 
with a screen 
0 
2-75 
72-50 
2 
70-50 
29-50 
The plant beginning to look un- 
healthy was now removed. 
Observations. — The remarkable clearness of the sky, and the warmth of the weather during these three 
days, was peculiarly favourable to the experiments, and will account for the large quantity of oxygen ob- 
tained, which was equal to 8'5 per cent., or 8‘5 x 6 = 51 cubic inches. Owing to the longer time that 
the plant continued in a state of health, the quantity of carbonic acid that disappeared did not 
so much 
exceed that of the oxygen given out as in the preceding experiments. 
Experiment 9. 
May 20 
4 r. m. Day dull, but free from rain: 
in the evening a little sunshine. 
Branch of a Lilac, having on it about 
fifty healthy leaves, each leaf on an 
average presenting a surface of about 
six square inches (50 x 6 = 300 
square inches to the whole) 
5 
5 
81 
2 
79 
21 
7 P. M 
0 
3-3 
80-75 
2 
78-75 
21-25 
May 21. 
a. m. Jar during the former part 
of the morning covered by an opake 
screen 
0 
2-25 
80 
2 
78 
22 
11^ a. m. Bright sunny day. Ther- 
mometer 65° 
0 
2-25 
79-5 
2 
77-5 
22-5 
H 
0 
o-oo 
77 
2 
75-0 
25-0 
mdcccxxxvi. z 
