13
& the plume towards the atmosphere. - -
Instance Sketch
The fact has been noticed by a great number
of veg.^e Physiologists & fully proved by the exp^ts
of Du Hamel , J Bonnet & J. Hunter - |_ The
cause has been a subject of much discussion
& it is only within the last two years
that any first experiment illustrations of it
have been offered to the public. - -
- The opinion of de la Hire was "that the
vertical position of the plume depended
upon the ascent of the sap in the vaporous
form" & the direction of the roots to
the weight of the descending fluid - |_ D.^r
Hales seems to have formed nearly the same
opinion as to the effect being mechanical -
but many other philosophers have referred
it to the peculiar vital powers of the plant. -
"It must depend" says ^D. Darwin (always anxious
to make plants inferior animals) upon excitability
The plumula at is stimulated by the Air into