blossoms a fortnight sooner than the indigenous ones.

Professor Kalm, in his Travels in New York, observes that the apple-trees
brought from England blossom a fortnight sooner than the native ones. In
our country the shrubs, that are brought a degree or two from the north,
are observed to flourish better than those, which come from the south. The
Siberian barley and cabbage are said to grow larger in this climate than
the similar more southern vegetables. And our hoards of roots, as of
potatoes and onions, germinate with less heat in spring, after they have
been accustomed to the winter's cold, than in autumn after the summer's
heat.

II. The stamens and pistils of flowers shew evident marks of sensibility,
not only from many of the stamens and some pistils approaching towards each
other at the season of impregnation, but from many of them closing their
petals and calyxes during the cold parts of the day. For this cannot be
ascribed to irritation, because cold means a defect of the stimulus of
heat; but as the want of accustomed stimuli produces pain, as in coldness,
hunger, and thirst of animals, these motions of vegetables in closing up
their flowers must be ascribed to the disgreeable sensation, and not to the
irritation of cold. Others close up their leaves during darkness, which,
like the former, cannot be owing to irritation, as the irritating material
is withdrawn.

The approach of the anthers in many flowers to the stigmas, and of the
pistils of some flowers to the anthers, must be ascribed to the passion of
love, and hence belongs to sensation, not to irritation.

III. That the vegetable world possesses some degree of voluntary powers,
appears from their necessity to sleep, which we have shewn in Sect. XVIII.