strongly attracting power, [the] whole [of] nature would then become one
unactive cohering lump." This may remind us of Herbert Spencer's words:
"Thus the essential characteristic of living organic matter, is that it
unites this large quantity of contained motion with a degree of cohesion
that permits temporary fixity of arrangement" (_First Principles_,
section 103). With regard to the way in which plants absorb and fix the
"air" which he finds in their tissues, Hales is not clear; he does not in
any way distinguish between respiration and assimilation. But as I have
already said, he definitely asserts that plants draw "sublimed and
exalted food" from the air.

As regards the action of light on plants, he suggests (p. 327) that "by
freely entering the expanded surfaces of leaves and flowers" light may
"contribute much to the ennobling principles of vegetation." He goes on
to quote Newton (_Opticks, query_ 30): "The change of bodies into light,
and of light into bodies, is very conformable to the course of nature,
which seems delighted with transformations." It is a problem for the
antiquary to determine, whether or no Swift took from Newton the idea of
bottling and recapturing sunshine as practised by the philosopher of
Lagado. He could hardly have got it from Hales, since _Gulliver's
Travels_ was published in 1726, before _Vegetable Staticks_.

Nevertheless, Hales is not quite consistent about the action of light;
thus (p. 351) he speaks of the dull light in a closely planted wood as
checking the perspiration of the lower branches, so that "drawing little
nourishment, they perish." This is doubtless one effect of bad
illumination under the above-named conditions, but the check to
photosynthesis is a more serious result. In his final remarks on
vegetation (p. 375) Hales says in relation to green-houses, "It is
certainly of as great importance to the life of the plants to discharge
that infected rancid air by the admission of fresh, as it is to defend
them from the extream cold of the outward air." This idea of ventilating
greenhouses he carried out in a plant-house designed by him for the
Dowager Princess of Wales, in which warm fresh air was admitted. The
house in question was built in 1761 in the Princess's garden at Kew,
which afterwards became what we now know as Kew Gardens. The site of
Hales' greenhouse, which was only pulled down in 1861, is marked by a big
wistaria which formerly grew on the greenho