460 Darwin . — On the Growth of 
It is not necessary to give the details ; it will be enough to 
say that on Sept. 18, 1890, the balance recorded 20 oz. ; on 
Sept. 22, 33I ; on Sept. 27, 62 oz. Therefore in the first four 
days it increased in weight at the rate of 3-44 oz. per day ; in 
the last five days at the rate of 5-65 oz. per day. This latter 
rate is equivalent to about 6*8 grams per hour ; it was there- 
fore evident that, with a better balance, it would be easy to 
record the changes in weight at short intervals. In the 
autumn of 1892 I made some observations on a gourd 
growing in a small greenhouse. The branch of about half 
a meter in length on which the fruit was borne, necessarily 
interfered with the freedom of the balance on which the fruit 
was placed, but this source of error is unavoidable, and one of 
which it is not easy to estimate the amount or the constancy. 
The instrument was a French druggist’s balance, capable of 
carrying 8 kilo, and turning with 0-5 gram when loaded with 
1,000 grams on each pan. 
In the following table I have expressed the rate of increase 
in milligrams per minute, so that the growth may be easily 
EXPERIMENT I. 
Time. 
Grams. 
Milligrams per 
minute. 
Sept. 6, 1892. 
5.42 p.m. 
704 
6.22 „ 
712 
200 
6.52 „ 
715 
9- 11 » 
729 
100.5 
Sept. 7. 
61. 1 
10 a.m. Few 
776 
small leaves re- 
moved 
10.6 a.m. 
7 6 9 
12.53 P- rn - 
787 
107.8 
3 4 2 » 
802 
88.7 
5-56 „ 
820 
134*3 
Sept. 8. 
64*3 
10.0 a.m. 
882 
2.30 p.m. 
890 
29-6 
5-30 „ 
897 
38.9 
9- 21 »> 
917 
86.6 
Sept. 9. 
964 
61. 1 
10. 10 a.m. 
