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4 of an inch from the apex of a young leaf nearly 4 inches in
length. Its movements were then traced during three days, but the tracing
is not worth giving. The leaf fell during the whole morning, and rose in
the evening and during the early part of the night. The ascending and
descending lines did not coincide, so that an irregular ellipse was formed
each 24 h. The basal part of the midrib did not move, as was ascertained by
measuring at successive periods the angle which it formed with the horizon,
so that the movement was confined to the terminal portion of the leaf,
which moved through an angle of 11o in the course of 24 h., and the
distance travelled by the apex, up and down, was between .8 and .9 of an
inch.
In order to ascertain the effect of darkness, a filament was fixed to a
leaf 5 ? inches in length, borne by a plant which after forming a head had
produced a stem. The leaf was inclined 44o above the horizon, and its
movements were traced on a vertical glass every hour by the aid of a taper.
During the first day the leaf rose from 8 A.M. to 10.


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