Royal Society. 379 
fet in the glafles Q^, R, S, ^6'. in OEiober and the following 
colder months, had not near the quantity of water conveyed 
into them, nor fo great an additional increafe by much, as thofe 
that were fet in jfune^ J'^i^^ ^"d the hotter months ; 'tis plain 
that water has no power of moving itfelf, or of rifing to that 
vaft height it does in the more tall and lofty plants 5 fo far 
from it, that it does not appear from any dilcovery yet made 
that its fluidity conlifts intheinteftine motion of its parts, there 
being no need of any thing more, to folve all the phenomena 
of fluidity, than fuch a figure and difpofition of parts as water 
has ; for corpufcles of fuch a make, and that are all abfolutely 
fpherical, mull have fo little contafl with each other, as to 
be always fufceptible of every the lightell impreflion imagi- 
nable to put them into motion'3 it is true, the parts of fire are 
not capable of moving themfelves any more than thofe ot water 5 
but being more fubtile, light, and a<^ive than thefe are, they 
are more eaiily put into motion: In fine, it is evident, and 
matter of fa(5l, that heat operates upon and moves the water, 
in order to its carrying on the work of vegetation. 
That the concourfe of heat is really neceffary in this work, 
appears not only from the experiments before us, but likewife 
from all nature, in fields, forefts, gardens and orchards 5 for 
we lee in autumn, as the power of the fun grows gradually 
lefs and lefs, fo its eflfe6ls on plants do remit, and their vege- 
tation flackens by little and little ^ its failure is firfl difcernible 
in trees, which being raifed higheft above the earth, require 
a more intenfe heat to elevate' the water, charged with their 
nourifhment to the extreme parts 5 fo that for want of frefla 
nutriment they fhed their leaves, unlefs they are fecured by a 
very firm and hardy conftitution as our ever greens are ^ next 
the fhrubs Ihed their leaves, and then the herbs and lower 
tribes 5 the heat at length not being fufficient to fupply even 
thefe, tho' fo near the earth, with an adequate fund of nou- 
rilhment^ as the heat returns the fucceeding fpring, they all 
' recruit again, being furniflied with freih liipplies and verdure 5 
and firft of all thofe which are loweft and nearell the earth, as 
herbs and fuch plants as require a leffer degree of heat toraife 
up the water with its earthy particles into them 5 then the flirubs 
and higher vegetables in their turns, and laftly the trees : But 
as the heat increafes, it grows too powerful, and hurries the 
earthy matter with too great rapidity thro' the more deli- 
cate plants, which therefore go off and decay 5 whilft others 
that are more hardy, and vigorous, and require a greater fhare 
B b b 2 o£ 
