In
the figure given (Fig. 157), the first dot was made at 8.30 A.M. August
2nd, and the last at 7 P.M. on the 3rd. During 12 h. on the first day the
petiole moved thrice downwards and twice upwards. Within the same length of
time on the second day, it moved five times downwards and four times
upwards. As the ascending and descending lines do not coincide, the petiole
manifestly circumnutates; the great evening fall and nocturnal rise being
an exaggeration of one of the circumnutations. It should, however, be
observed that the petiole fell much lower down in the evenings than could
be seen on the vertical glass or is represented in the diagram. After 7
P.M. on the 3rd (when the last dot in Fig. 157 was made) the pot was
carried into a bed-room, and the petiole was found at 12.50 A.M. (i.e.
after midnight) standing almost upright, and much more highly inclined than
it was at 10.40 P.M. When observed again at 4 A.M. it had begun to fall,
and continued falling till 6.15 A.M., after which hour it zigzagged and
again circumnutated. Similar observations were made on another petiole,
with nearly the same result.
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