84 On the Use of Air-Vessels in Plants. 
and watched them for hours, without seeing one.Jubble of waiter 
transpire, that I am well assured of the truth of the above fact; 
and that, when not covered by a Cryptogamza, the floating leaves 
are always perfectly dry; which they could not be with the per- 
Spiration attributed tothem. 1 haye said that the water plants 
have no hairs, that is, that none of the uninclosed parts have 
any; which appears to me to be a strong proof of two facts I 
have much wished to establish; viz. that the hairs, and those in- 
struments in general taken for perspiration, are on the contrary 
intended to bring moisture to the plants, instead of drawing li- 
quid from them; and that there exists such a thing in vegetation 
as a skin impervious to water, which covers all leaves and most 
other parts, and is of peculiar use to water plants. These two 
points are of great importance to phytology. 1 have continually 
brought them forward in every specimen that gave proof of their 
existence; and former evidence is much added to, I think, by what 
follows. Though leaves and the parts under water uncovered by 
vails, have no hairs, yet the flowers which shoot their spikes 
above, and the buds while thoroughly defended from the stream, 
have a few ; and what is most curious, they are filled with water. 
The bud before the flower develops is covered by a treble vail, 
so thoroughly impervious to water, that one of them is usually 
inflated with air, that it may more effectually guard the pollen, 
and prevent the introduction of moisture. Assured that the hairs 
were never replenished from the plant, but that they gained their 
liquid from the atmosphere alone, I wished to try how hairs when 
so situated, could obtain the water that inflated them: taking 
therefore two glasses and placing them one within another, well 
guarded below from any moisture by a thick luting, I covered the 
whole apparatus with water, and left it for the night; when the 
next morning | found the interior of the inward glass strewed 
with pellicles of water enough to fill all the little hairy cylinders 
the buds contain; showing that evaporation ean pierce through 
a double glass. There cannot be a stronger proof that the hairs 
possess some peculiar power which enables them to draw mois- 
ture from the atmosphere, than this. Though that I gave in a 
late letter, shows it is not water alone that is procured in this 
manner, since oil is also received by the hair; and in roses, 
the luscious red juice produced or concreted in them, may be 
traced afterwards entering the plant, and running in appropriate . 
vessels even to the valves of the leaf, 
Having now shown all that concerned the leaves and air-vessels 
of the water plants, I wished to ascertain whether they differed 
from other plants in this respect; or whether, like them, they 
formed their seeds and buds in the root? To prove this, I pro- 
cured a large water-lily of the dutea species, and cut many pieces 
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