: V E G 
tSwing months, had not near the Quantity of water 
lent up into them, or fo great an additional increafe 
by much as thofe that were let it* June, July, or the 
hotter months. 
It is plain the Water has rid power of moving itfelf, 
or rifing to the vaft height it doth, in the more tall 
and lofty plants *, fo far from it, that it doth not ap- 
pear by any difcovety yet made, that even its own 
fluidity conftfts in the inteftine motion of its parts, 
whatever the Caftefians think. 
Indeed we want nothing more to folve all the pheno- 
mena of fluidity, than fuch a figure and difpofition of 
parts as water has : fpherical corpufcles mult Hand fo 
ticklifh upon each other, as to be ltilceptible of every 
impreflion, and though not perpetually in motion, 
muft be always ready and liable to be js'ut into it by 
any the flighted: force imaginable. It is true, the 
parts of fire or heat are not capable of moving them- 
felves any more than thofe of water, but they are 
more fubtile, light, and a£Hve than thofe are, and fo 
the more eafily put in motion. 
That the concourfe of heat is really neceflary in this 
work, appears not only from the experiments before 
iis, but from all nature, from the fields and forefts, 
gardens and orchards. We fee in autumn, as the 
fun’s power is gradually lefs and lefs, fo its effed on 
plants is remitted, and Vegetation flackens by little 
dnd little. 
Its failure is firft difcernible in trees, which, being 
raifed higheft above the earth, require a more intenfe 
beat to elevate the water charged with nourifhment to 
their tops, fo that, for want of frefh fupport and nu- 
triment, they fhed their leaves, unlefs fupported by a 
very firm and hard conftitution, as our evergreens are. 
Next, the fbrubs part with theirs ; then the herbs and 
lower tribes, the heat at length not being fuffkient to 
fupply even to thefe, though fo near the earth, the 
fund of their nourifliment. 
As the heat returns the fucceeding fpring, they all 
recruit again, and are furniflied with frefh fupplies 
and verdure ; but firft, thofe which are loweft, and 
neareft the earth, and that require a lefs degree 6f heat 
to raife the water with its earthy charge into them, 
then the fhrubs and higher vegetables in their turn, 
and laftly the trees. 
As the heat increafes, it grows too powerful, and 
hurries the matter with too great rapidity through the 
finer and more tender plants ; thefe therefore go off 
and decay, and others that are more hardy and vigo- 
rous, and require a greater degree of heat, fucceed in 
their order. By which mechanifm, provident nature 
furnifhes us with a very various and different entertain- 
ment, and what is beft fuited to each feafon all the 
year round. 
As the heat of the feveral feafons affords us a diffe- 
rent face of things, the feveral diftant climates fhew 
the different feenes of nature, and produftions of the 
earth. 
The hotter countries ordinarily yield the largeft and 
tailed trees, and thofe too in a much greater variety 
than the colder ; even thofe plants common to both 
attain to a much greater bulk in the fouthern, than in 
the northern climates. 
Nay, there are fome regions fo cold, that they raife 
no vegetables at all to a confiderable fize ; this we 
learn from Greenland* Iceland, and other parts of like 
cold fituation and condition : in thefe there are no 
trees, and the fhrubs are poor, little, and low. 
Again, in the warmer climates, and fuch as furnifh 
trees and the large vegetables, if there happen a re- 
miffion or diminution of the ufual heat, their grodudti- 
ons are impeded in proportion. Our own fummers 
give us proof enough of this, for though at fuch times 
there is heat fufficient to raife the vegetative matter 
into the lower plants, as Wheat, Barley, Peas, and 
the like, and we have plenty of Strawberries, Rafpber- 
ries, Goofberries, Currants, and the fruits of fuch ve- 
getables as are low, and near the earth, and a moderate 
ftore of Cherries, Plums, &c. and fome others, that 
grow at fomething of a greater height, yet our Apples, 
V E L 
Pears, Peackes, .Ne&aHiieS, and Grapes, and the ph> 
dudtion of warmer countries, have been fewer, and 
thofe not fothoroughly ripened, and brought to per- 
fection as they are in more benign feafons. 
Nor is it that heat only which promotes Vegetation, 
but any other indifferently, according to its power and 
degree, as we find from dur ftoves, hot-beds, &c. 
And by the rightly adapting of thefe artificial heats, 
the Englifli gardeners have of late years fo much im- 
proved their art, as in a great meafure to fupply the 
ivant of natural heat, and to vie with the people, who 
inhabit countries feveral degrees fouth of England, in 
the early products of efculent plants, and the accele- 
rating and ripening the fruits of the warmeft climates. 
And as the knowledge of Vegetation is improved, 
and the praditioners of the art are better acquainted 
With the theory, it may be hoped the art may be far- 
ther extended and improved ; therefore it is highly 
neceflary, that the theory of Vegetation fhouid beltu- 
died by every perfon who propofes to make any pro- 
ficiency in gardening and agriculture. 
VELLA. Lin. Gen. Plant. 714. Spanifh Crefs. 
The Characters are, 
the emfalemeut of the flower is cylindrical , and compofed 
of four linear obtufe leaves, which drop off. T'he flower 
has four petals in form of a crofs , whofe tails are the 
length of the impalement, and fix fiamina of the fame 
length, two of which are a little fhorter , terminated bv 
fingle fummits , and ati oval germen , fupporting a conical 
fiyle, crowned by a fingle ftignia . the germen afterward 
turns to a globular capfule with two cells, divided by an 
intermediate partition twice as large as the pod, and is oval 
and eredt, firetching beyond the capfule i each cell con- 
taining one feed. 
This genus of plants is ranged in the firft fedion of 
Linnaeus’s fifteenth clafs, which includes thofe plants 
whofe flowers have two long and two fhorter ftamina, 
and the feeds are included in fhort pods. 
The Species are, 
1. Vella {Annua) foliis pinnatifidis, filiculis pendulis. 
Lin. Sp. Plant. 641. Vella with wing-pointed leaves, and 
hanging pods. Nafturtium fylveftre Valentinum. Cluf. 
Hift. 2. p. 130. Wild Crefs cfValentia. 
2. VellA {Pfeudo Cytifus) foliis integris obovatis ciliatis 
filiculis eredis. Lin. Sp. Plant. 641. Vella with entire, 
oval, ciliated leaves, and eretd pods. Pfeudo cytifus fiore 
leucoii luteo. C. B. P. 230. Baflard Cytifus with a 
flower like the yellow Wall-flower. 
The firft fort grows naturally in Valentia ; it is aa 
annual plant, which feldom rifes more than one foot 
high. The ftalk divides toward the top into feveral 
branches, each ending in a loofe fpike of flowers, 
which are followed by round fwelling pods, having a 
leafy border or creft on the top, which is hollowed 
like a helmet. The pod opens with two valves, and 
has two cells, which contain roundifh feeds like thofe 
of Muftard. The leaves are jagged, and end in ma- 
ny points. 
This plant is preferved in gardens for the fake of va- 
riety, but as it is not very beautiful, nor of any ufe, 
it is feldom cultivated unlefs in botanic gardens. If 
the feeds of this plant are permitted to fcatter, the 
plants will come up and thrive very well ; of if they 
are fown in autumn, they will fucceed much better 
than thofe which are fown in the fpring 5 for when the 
feafon proves dry, thofe feeds which are fown in the 
fpring, frequently lie in the ground till the following 
autumn before the plants appear whereas thofe 
which are fown in autumn, always come up foon after, 
or early in the fpring, fo will more certainly produce, 
ripe feeds. Thefe plants fhouid not be tranfplanted, 
therefore the feeds fhouid be fown where the plants 
are to remain, and if they are kept clean from weeds, 
and thinned where they are too clofe, they will require 
no other culture. 
The fecond fort grows naturally in Spain. The 
leaves of this are entire, hairy, and fit clofe to the 
ftalk they are oval, and of a grayifh colour. The 
ftalks become ligneous •, they rife about two feet 
high, and are terminated by roundifii bunches of pale 
yellow 
