472 
Darwin . — On the Growth of 
in a small cool greenhouse, which, though it answered well 
enough, was inconvenient in one important respect, namely, 
that it had no proper blinds, so that the shading had to be 
effected by mats or other material thrown on the roof. The 
plant was kept under observation for eight days, during which 
the rate of growth showed a steady decrease, as if it were the 
end of a grand period. (See Table A on p. 471). 
I do not give the details of all these days ; Exp. 1 1 gives a 
fairly typical day. 
EXPERIMENT XL— Sept. 8, 1892. V 5. 
Time. 
Reading. 
Rate. 
Temp. C°. 
mm. 
H per min. 
9.55 a.m. 
8-21 
21.5 
Bright sun, blinds down 
IO.IO „ 
•243 
+ 3*3 
21.0 
9.44 a.m. 
•42 „ 
.32 
2.4 
20.3 
Sunny. 
.56 „ 
•35 
2-1 
19-5 
11. 11 „ 
•37 
t -3 
19.8 
12.2 p.m. 
•432 
1*2 
20.0 
Occasional clouds. 
•23 „ 
•445 
0.6 
20-0 
Sun shining on leaves, 
the blinds altered so as 
to shade them. 
•44 » 
.462 
0.8 
20-0 
I - 3 ° „ 
•52 5 
x -4 
I 9'3 
Sun and cloud. 
2.3 „ 
•57 
i A 
20-0 
Sun. 
•23 „ 
? 
Table shaken, reading 
therefore doubtful. 
•43 „ 
.640 
19-5 
Clouded. 
3-3 >1 
.66 
1*0 
19-5 
Sunny. 
•44 » 
.70 
1-0 
20-5 
4-5 „ 
.722 
1.0 
I9.9 
•34 » 
•745 
o-8 
20*0 
Sunny. 
5- T 3 „ 
.820 
1 '9 
•23 „ 
Sun behind trees. 
.36 „ 
•890 
3 -o 
18.8 
Lamp lighted to keep 
the house warm. 
.56 „ 
•940 
2-5 
16.3 
Roof covered with mats : 
6.25 „ 
•995 
i -9 
l 6-0 
fairly dark. 
9 -i 4 
9-21 
1*2 
n -5 
Fig. 5 gives the result graphically. The dip in the curve at 
12.23, when the sun shone on the leaves, should be noted ; 
also the sudden rise when the sun was off the house ; also the 
marked nocturnal fall. 
In order to ascertain whether similar growth- changes are 
