( 225 ) 
felfy and where the Motio?i firft begins, this is no fit Place 
to enquire. 
That the Conconrfe of Heat in this Work is really ne- 
cejfary\ appears, not only from the Experiments before 
us, but from all Nature : From our Fields and Forejh^ 
our Gardens and our Orcbyards. We fee in Autumn, as 
the Sun^s Power grows gradually lefs and fo its ef- 
fedls on Plants is remitted, and their Vegetation Jlackens 
by little and little. Its Failure is firft difcernible in 
, Trees. Thefe are raifed higheft above the Earth : and 
require a more intenfe Heat to elevate the Water, char- 
ged with their Nourijhment, to the Tij/j and Extremities 
of them. So that for want of yr*?/?? fupport and Nutri-- 
ment they (hed their heaves, unlefs fecured by a very 
and i&/:?r<5^ Conjlitution indeed, as our ever-greens 
are. Next the Shrubs part with theirs : and tlfen the 
Herbs and ^u'^t Tribes-^ the i?!?^^ being at length 
not fufficient to fupply even thefe^ tho' fo near the 
"Earth, the F/^W of their NouriJIment. As the iiZ^'^/ re- 
turns the fucceeding Spring, they all recruit again : and 
are furnifli'd with frejh fupplies and verdure. But firft 
thofe which are lowefi and near eft the Earth, Herbs, and 
they that require a /^r degree of J?f^/ to raife the 
Water with its Earthy Charge into them. Then the 
Shrubs and higher Vegetables in their turns : and laftly 
the Trees. As the Heat encreafes, it grov/s too power-- 
ful^ and hurries the Matter with too great rapidity tho- 
row the finer and more tender Plants. Thefe therefore 
go off] and decay : and others that are more hardy and 
vigorous, and require a greater fiare of Heat, fucceed 
in their Order. By which Mechanifm provident Nature 
furnifhes us with a very various and differing Entertain- 
ment : and what is be/i fuited to each Seafon, all the 
Tear round. 
As 
