5^5 
Culture of Algae. 
following days; but by the 25th it was evident that growth 
was taking place in other pieces scattered over the field, and 
on the 26th I fixed another segment, measuring 45 /x long 
x 2-3 fi broad, and obtained the following measurements. See 
Plate XXVIII. 
Date. 
Hour. 
Temp. 
Length. 
Elongn. 
Aug. 26. 
11.30 a.m. 
O 
P 
45 /* 
11 
27. 
3.10 p.m. 
25 
58-5 /* 
13-5 /* 
H 
28. 
10.20 a.m. 
21’5 
68-4 /x 
9 - 9 /* 
11 
11 
12.50 p.m. 
21.5 
72.9 /i 
4-5 /* 
1 1 
11 
3.30 „ 
22 
76-5/* 
3*6 At 
19 
19 
6.15 >, 
21.5 
78-75 /* 
2*25/4 
29. 
10.0 a.m. 
18.5 
85.5 /x 
6-75/4 
11 
12 noon 
21 
9°*45 /* 
4 - 95 /* 
?? 
11 
3-35 P- m - 
21 
99.0/4 
8 - 55 /* 
11 
11 
8.0 „ 
20.5 
105.75 /* 
6*75/4 
11 
3°. 
9.0 a.m. 
19-5 
109-0 / j . 
3 - 25 /* 
11 
1 1 
1. 15 p.m. 
23 
IJ 3*5 /* 
4 - 5 /* 
11 
11 
3-30 „ 
23 
123.5/4 
10*0 (x 
11 
11 
6-45 „ 
22 
1 3 2 *75 /* 
9.25 fX 
„ 
Si- 
9.0 a.m. 
18.5 
137-25/* 
4 - 5 /* 
11 
11 
12 noon 
20 
148.5 /t 
11.25/4 
11 
3.30 p.m. 
21 
162*0 [X 
13 - 9 /* 
>1 
11 
6.50 „ 
20 
1 7 I -°A t 
9 - 0/4 
Sept. 
I. 
9.15 a.m. 
i 7 
175-5 /* 
4-5/* 
11 
12.30 p.m. 
i9-5 
189 IX 
13 - 5 /* 
11 
11 
3-5 » 
20 
198 n 
9 /* 
11 
11 
6.40 „ 
21 
207/4 
9 /* 
11 
11 
9*45 » 
20 
211*5 /* 
4-5 /* 
11 
2 . 
5.25 a.m. 
17-5 
211*5 H 
0 
91 
11 
10.15 „ 
18 
213 75/* 
2*25/4 
11 
11 
1.10 p.m. 
20 
216*0 ix 
2.25 fX 
11 
3 - 
10 0 a.m. 
16-5 
235 -° /* 
19/* 
From the fact that this filament was held by the tail, as 
it were, I could not determine whether one only or both 
ends were growing. 
It took from 11.30 a.m. on Aug. 26 to the same hour on 
Aug. 29 (i. e. 72 hours) to double its length — from 45 to 90 j a — 
and this appears to be very slow growth, though I am not 
aware that measurements exist to help us in deciding how slow. 
The next doubling of the length — 90-180 jx — was completed 
about 10 a.m. on Sept. 1 — i.e. in about 70 J hours. 
In a diagram made at the time (Plate XXVIII), the curve 
of growth shows very clearly that no elongation took place 
during the hours of darkness, but that growth and assimilation 
are coincident, a point which appears worthy of note in view 
of what we know as to the effect of light on growing organs. 
P p 2 
