Page:Cyclopaedia, Chambers - Supplement, Volume 1.djvu/765

 FRO

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clufter, where the whole body of the trees in the clutter kept oft" the north winds, and where the fouth fun had molt pow- er. It was in thefc places that the young ihoots made their iirft appearance, and were the moil ftrong and vigorous ; the eaft fides of the clufters next fhot out ; after thefe the weft, and finally the north. A week afterwards there came on a ve- ry fevere frojl with a clear air, and examining the fhoots on the fouth fides of the clufters, they were found all decayed and withered, and looked black, while thofe which wereex- pofed to the north wind, which at that time blew very fharp- ly, were found very little hurt. The eaft and weft fides were about equally damaged ; aud the ftate of the ihoots on the fame fides of all the clufters or thickets was the fame. On the fourteenth, fifteenth and twenty-fecond of May, there were fevere frofly mornings ; and inquiring into the ftate of the fhoots again, the cafe was juft the fame as before, all the fhoots on thofe fides of the thickets which were defended from the north and north-weft winds, which then blew, were greatly damaged, while every thing that was expofed to the wind was fcarce found to have fuftered at all. Thefe obfervations indifputably prove, that tho' the frojl is moll violent at the north, yet the injury done to vegetables by frojl is lead: of all in that expofure;

This is an obfervation directly oppofite to the common opinion, yet it is not the lefs true, nor is it any way difcordant to rea- fbn. We find by a number of experiments, that humidity j s the thing that makes frojl fatal to vegetables, and therefore every thing that can occaiion humidity in them, expofes them to thefe injuries, and every thing that can prevent or take off an over proportion of humidity in them, every thing that can dry them, tho' with ever fo increafed a cold, muff, prevent or preferve them from thofe injuries. Numerous experi- ments and obfervations tend to prove this, ft is well known that vegetables always feel the froft very defperately in low places where there are fogs. The plants which ftand by a liver fide, are frequently found deftroyed by the fpring and autumnalyro/?*, while thofe of the fame fpecies, which ftand in a drier place, fufter little, or perhaps not at all by them - and the low and wet parts of forefts are well known to pro- duce worfe wood than the high and drier j and the coppice wood in wet and low parts of common woods, tho' it pufli out more vigoroully at firft than that of other places, yet never comes to fo good a growth ; for the frojh of the fpring killing thefe early top fhoots, obliges the lower part of the trees, to throw out lateral branches : and the fame thing hap- pens in a greater or leffer degree to the coppice wood that grows under cover of larger trees in great foreftsj for here the vapours not being carried off, either by the fun or wind ftagnate and freeze, and in the fame manner deftroy the young fhoots, as the fogs of marfhy places. It is a general ob- servation alfo, that the fro]} is never hurtful to the late fhoots of the vine, or to the flower-buds of trees, except when it follows heavy dews, or a long rainy feafon, and then it never fails to do great mifchief, tho' it be ever fo flight. The frojl is always obferved to be more mifchievous in its confequences on newly cultivated ground than in other places ; and this is becaule the vapours which continually arife from the earth, find an eaficr paifage from thofe places, than from others ; trees alfo which have been newly cut, fufter more than others by the fpring fro/Is, which is owing to their (hoot- ing out more vigorously.

Frofts alfo do more damage on light and fandy grounds, than on the tougher and firmer foils, fuppofing both equally dry ; and this feems partly owing to their being more early in their productions, and partly to their lax texture, fuffering a great- er quantity of vapours to tranfpire.

It alfo has been frequently obferved, that the fide fhoots of trees are more fubjecf to perifh by the fpring fro/Is, than thofe from the top; and Mr. Buffon, who examined into this with great accuracy, always found the effects of the fpring frojh much greater near the ground than elfewhere. The fhoots within a foot of the ground quickly pcrifhed by them : thofe which ftood at two or three foot high, bore them much better; and thofe at four foot and upwards frequently remained wholly unhurt, while the lower ones were wholly deftroyed.

Thefe are a feries of obfervations, which have proved beyond all doubt, that it is not the hard fro/Is which fo much hurt plants, as thofe fro/Is, tho' lefs fevere, which happen when they are full of moifture; and this clearly explains the account of all the great damages done by the fevere frojls beino- on the fouth fide of the trees which are affected by them, tho' that fide has been plainly all the while lefs cold than the north. Great damage is alio done to the weftern fides of trees and plantations, when after a rain with a weft wind, the wind turns about to the north at fun fet, as is frequently the cafe in Ipring, or when an eaft-wind blows upon a thick fog be- fore fun rifing. Memoirs, Acad. Scien. Par. 1737. I rost fplit, a phrale ufed by our farmers to exprefs fuch trees as have large cracks in their trunks and branches, rendering them unfit for the ufes they would otherwife have fold for, Surn. Vo L. I.

and by that means greatly debafing their value. It has been pretended by fome, that thefe rents and cracks in trees, were owing to other caufes; but we have had innumerable inftances and thole well recorded of the immediate effefl of hard frojls on the ftrongeft trees fpoiling them in this manner; and it ap- pears very rational, to fuppofe all thefe injuries do really come by the fame means, and are properly called by this term. Vid. fupra, and the Phil. Tranf. N°. 165.

FROT H, in the manege, is a moift white matter that oozes from a horfe's mouth, otherwife called foam. A horfe rhat by champing on his bridle, throws out a great deal of froth, is judged to be a horfe of mettle and health, and to have a cold frefh mouth.

Froth fpit, or cuchwfpit, a name given to a fort of white froth or Ipume very common in the fpring, and firft months of the lummer, on the leaves of certain plants, particularly on thofe of the common white field lychnis, or catch-fly, thence call- ed by fome Spotting poppy. All writers on vegetables have taken notice of this froth, tho' few have underffood the caufe or origin of it, till of late. Many imagined it an exhalation from the earth, fome have efteemed it as its name exprefi'es the faliva of the cuckow, others the extravafated juices of the plant, and fome a hardened dew. But all thefe are erroneous opinions, and the true account of it is that it owes its origin to a fmall infefl.

There are very frequently to be feen in the fummer months a. fort of fmall leaping animals, called by fome the flea-grafs- hoppers, becaufe they are very fmall, and leap like a flea ; thefe little creatures have each a pointed probofcis, by means of which they fuck the juices of the plants, they are found upon. Thefe animals lay their eggs in autumn, from which in the fpring following the young ones are hatched, and tiiefe are at firft tenderly fheltei'd from injuries by a delicate and thin membrane, which makes a fort of nymph, having the linea- ments of all the parts of the animal, which is to iffue from it. When it is firft hatched from the egg, it is a fmall white point on the leaf, not larger than the point of a needle ; a few days after, it is greenifh, its colour changing with the juices of the plant on which it feeds: in this ftate it not un- aptly refembles that fmall fpecies of frog, called the tree-frog, which is common on the branches of trees in many places ; it moves about very fwiftly in this ftate, tho' ftill covered with its membrane, but till it gets rid of that, it can neither leap nor fly.

The manner in which this little creature forms this froth up- on the plant is this ; it applies its anus clofe to the leaf, and difcharges upon it a fmall drop of a white vifcous fluid, which containing fome air in it, is foon elevated into a fmall bubble ; before this is well formed, it depofits fuch another drop, and fo on till it is every way overwhelmed with a quantity of thefe bubbles, which form the white fi-oth which we fee. It adds to this upon occafion, but never moves from under it till it has got rid of its enveloping membrane, or arrived from the nymph ftate to that of the perfect animal. It throws out thefe globules of vifcous humor, by a fort of dilatation, and contraflion of its belly ; and as they fucced one another, it difpofes them every way round it with its feet. A proof, that while thefe animals are in this imperfea ftate, and covered with froth, they yet feed on the juices of the plant, is, that if one of them be placed on a leaf of mint, or any other fuch plant, the leaf on which they live will never grow beyond the fize it was of, when the animal was placed upon it, while the oppofite leaf will acquire its full dimenfions. When the animal has quitted its nymph ftate, it makes no more froth, but leaves that under which it had lived, and takes its courfe freely about the plant.

FROWER, an edged tool ufed in cleaving wood into laths. Ray's Engl. Words, p. 37.

FRUCTIFEROUS properly denotes any thing that produces fruit ; but in a more large or figurative fenfe, is ufed by lord Bacon, and others, for fuch experiments in natural philofophy, as prove advantageous to the experimenter in point of gain or profit.

FRUCTIFICATION of plants. See Generation, Pr.ANT,cfr.

FRUCTISTjE, in botany, that fet of authors who have at- tempted the eftablifhing the clafles and diftincfions of plants upon the fruit, feed, or receptacle of thefe in plants. Of this lift are Gefalpinus, Morifon, Ray, Herman, and Boer- haave. format Fund. Bot. p. 2.

FRUIT,( Cy<-/.) the production of a tree or plant for the propaga- tion or multiplication of its kind. In this fenfe the word takes in all kinds of feeds with their furniture. But botanifts ufually underftand by it that part of a plant wherein the feeds are con- tained.

The fruit in all plants is the produel or refult of the flower, or that for the production and nutrition of which the flower was intended. The ftructure and parts of different fruits are dif- ferent in fome things ; but in all the fpecies, the effential parts of the fruit appear to be only continuations or expanfions of thofe which are feen in the other parts of the tree ; and the fame fibres arc continued to them from the root. An apple 1 1 T cut