vertical glass; but the tracing is not given, as the hypocotyl was not
secured, so that it was impossible to distinguish clearly between its
movement and that of the cotyledon. The cotyledons rose from 10.30 A.M. to
about 3 P.M.; they then sank till 10 P.M., rising, however, greatly in the
latter part of the night.
[page 23]
The angles above the horizon at which the cotyledons of another seedling
stood at different hours is recorded in the following short table: --

Oct. 20 2.50 P.M...25o above horizon.
Oct. 20 4.20 P.M...22o above horizon.
Oct. 20 5.20 P.M...15o above horizon.
Oct. 20 10.40 P.M...8o above horizon.
Oct. 21 8.40 A.M...28o above horizon.
Oct. 21 11.15 A.M...35o above horizon.
Oct. 21 9.11 P.M...10o below horizon.

The position of the two cotyledons was roughly sketched at various hours
with the same general result.

In the following summer, the hypocotyl of a fourth seedling was secured to
a little stick, and a glass filament with triangles of paper having been
fixed to one of the cotyledons, its movements were traced on a vertical
glass under a double skylight in the house. The first dot was made at 4.20
P.M. June 20th; and the cotyledon fell till 10.15 P.M. in a nearly straight
line. Just past midnight it was found a little lower and somewhat to one
side. By the early morning, at 3.45 A.M., it had risen greatly, but by 6.20
A.M. had fallen a little. During the whole of this day (21st) it fell in a
slightly zigzag line, but its normal course was disturbed by the want of
sufficient illumination, for during the night it rose only a little, and