impossible to be accurate on this head, as the more obliquely the plant was
viewed, after it had moved for some time, the more the distances were
exaggerated.

We endeavoured to observe the circumnutation of the cotyledons, but as they
close together unless kept exposed to a moderately bright light, and as the
hypocotyl is extremely heliotropic, the necessary arrangements were too
troublesome. We shall recur to the nocturnal or sleep-movements of the
cotyledons in a future chapter.

Fig. 12. Gossypium: circumnutation of hypocotyl, traced on a horizontal
glass, from 10.30 A.M. to 9.30 A.M. on following morning, by means of a
filament fixed across its summit. Movement of bead of filament magnified
about twice; seedling illuminated from above.

Gossypium (var. Nankin cotton) (Malvaceae).--The circumnutation of a
hypocotyl was observed in the hot-house, but the movement was so much
exaggerated that the bead twice passed for a time out of view. It was,
however, manifest that two somewhat irregular ellipses were nearly
completed in 9 h. Another seedling, 1 ½ in. in height, was then observed
during 23 h.; but the observations were not made at sufficiently short
intervals, as shown by the few dots in Fig. 12, and the tracing was not now
sufficiently enlarged. Nevertheless there could be no doubt about the
circumnutation of the hypocotyl, which described in 12 h. a figure
representing three irregular ellipses of unequal sizes.

The cotyledons are in constant movement up and down during the whole day,
and as they offer the unusual case of moving downwards late in the evening
and in the early part of the night, many observations were made on them. A
filament was fixed along the middle of one, and its movement traced on a