Page:Cyclopaedia, Chambers - Supplement, Volume 1.djvu/824

 GRA

G R A

U a common in Egypt and Arabia, and is found in many parts of the world befide. We have of it in the weft of England very little inferior to the Oriental. The whitifl) red granite is fomctimes found in form of large 'ftrata, but much more frequently in large loofe nodules. It is very little inferior in beauty to the Oriental granite-, and is of a lefs coarfe and rude texture ; it's ground colour has 'different degrees of its red tinge, and is fometimes even whitifh. This is beautifully fpangled with black, white, and yellow ; much in the fame manner as the Oriental kind, and it is equally hard, and capable of as elegant a polilh. It is very plentiful th many parts of the iiland of Minorca, from whence we might have it in abundance, and it would ■make very beautiful tables, CSV. The rough mattes of it are fometimes found alio on the Shores of our iiland of Gucrnfey, whence they are taken up for ballaft for fhips, and are fometimes by this means brought among; us and ufed in the pavements of our ftreets. Hill's Hilt, of Foil", p. 500.

GRANULATION of metals [CycL) in allaying, is the re- ducing metals into very (mail particles, that they may the more readily fufe, and the more equally mix with other bodie: in fome of the nicer operations.

This is done more coariely in the wet way, by means of running them into water through a new broom, or rol- ling them about in a hollow cylinder contrived on pur- pole ; hut the nicer and finer way is the dry method, by means of a wooden box chalked within. Lead is vcrv nicely granulated this way, and it is to be done in the following manner.

Put a quantity of lead into an iron ladle, and melt it flowly over a gentle fire ; fo foon as it is perfectly liquid, pour it into a round wooden box, with a wooden cover well fitted to it, and both that and the cavity of the box well rubbed over with chalk ; ftuit the box immediately when the melted metal is in, and fhake it violently, fo that the metal within may be agitated forcibly againft all parts of the box ; con- tinue this agitation till the metal is cold ; and on opening the box, you will find the greater part of it finely granulated, or comminuted into very final] porous grains. Let the chalk that adheres to thefe grains be warned off, and then fift them to make them of an equal fize.

Lead, tin, and brafs, are the molt proper metals for this procefs, fuice thefe, when ready to melt, are always ex- tremely brittle, in fome degree like wetted fand. The chalk with which the iniide of the box is rubbed over gives the furface a great refitting force, and keeps it from being burnt ; while the metal dafhed againft its fides, being ex- tremely brittle jutt as it becomes folid, is broken into a mi- nute powder, not to be obtained any other way than by this operation.

There are however fome cautions necefTary in the manage- ment of this. The lead mutt: not be melted at too fierce a nre; for this occafions a fkin upon the furface, which how- ever often it be taken away, is always immediately fuc- with the metal during the fhaking, makes the whole tenaci- ous, and much obftructs the operation. Though the fire is not to be fierce, the lead however mutt be all perfectly fluid ; otherwife it will concrete almoft as foon as poured into the box, and little powder will be produced. This fort of granulation cannot be obtained from fuch me- tals as are the more tenacious, the nearer they come to fu- fion, as gold, filver, <sc. Thefe therefore can only be gra- nulated the other and coarfer way, by means of water. Cra- mer's Art. Ail', p. 70.
 * eeded by another ; and the matter of thefe fkins mixing

GRANULOSE Roots, are thofe compofed of fmaller knobs than the grumofe ones, and refembling fo many grains of corn ; of this fort is the white iaxifrage.

GRANUM Vir'tde, in botany, a name given by fome au- thors to the turpentine tree. The fruit of this tree is red- difti while unripe ; but as it ripens it becomes of a deep blucifh green colour, and hence the name.

GRAPES (CycL) — Thofe kinds of grapes which arc thin fkin- ed, grow fooner ripe than others, and will thrive in a tem- perate climate where the others will not. If it happen that grapes are ftruck with hail at the time that they are large and near ripening, they never become ripe at all, but harden and fo remain. Portzius de Vin. Rhcn.

We have in the Philofophical Tranfactions a remarkable account of the change of colour in grapes of the fame tree. A mufcadine grape tree was railed from a cutting of a pa- rent vine of this kind, whofe fruit was white ; it was planted againft an eaftern wall, where it had the benefit of the fun from its rifing, to half an hour after twelve. The foil a ftiff clay, but rendered fitter for the growth of this fort of tree, by a mixture of rubbifh of an old wall. At about five years ftanding it was fo pruned, as to make it fhoot two principal branches, one to the right, the other to the left hand ; from hence it fhot twenty two inches on each fide, before it came to a joint. That on the right was a very luxuriant branch, as thick as the body of the tree, the other about half that bignefs. The leaves on the right hand were alfo of twice the bignefs of thofe on the left, and indeed larger than the leaves of the parent tree ; but 4

what is moft Angular is, that the luxuriant branch produced annually fine black grapes in large bunches, and the left hand branch white ones. But the white were often in the great- eft quantity, though the black grew on. the much ftronger branch. It is obfervable, that in all thofe vines which bear black and blue grapes, that the leaves die red; but in this tree, whofe origin was from a white grape, the leaves on that branch which bore black grapes died white, as well as thofe on the other. The fucceeding year, the number of the branches on the right hand fhoot were greatly encreafed in number, and the fucceeding year all bore fine deep black grapes in very large numbers. Phil. Tranf. N° 366. p. 102. Ifolf -Graves. See Lycostaphyla. Grape galls, in natural hiftory, a name given by authors to a fpecics of protuberances refembling clutters of grapes, and when ripe of a reddifh colour, which are found hanging from the oak at fome feafons of the year. Thefe are

ge- nuine galls, though of a peculiar kind ; and owe their ori- gin to a very fmall four winged black fly. This little creature depofits its eggs either on the furface, or within the fub- ftance of thofe pedicles of the oak which nature has deftincd for producing the catkins, or fmall flowers of that tree. The biting and fucking of the worms, which are produced from thefe, occafion a wrong derivation of the juices to the part, and the confequence of this is, that inttead of flowers, there appears a protuberance over the part where each of thefe infects is lodged. This tubercle at firtt is fmall, and of a pale greenlfh colour, but it finally becomes yellowifh, or reddifh, and is juicy and large. A number of thefe Hand- ing clofe together upon the ftalk, give the appearance of a clutter of grapes on the bunch, and when any one of thefe is opened, there is found in it either a worm, a chryfalis, or a fly, the animal never quitting its habitation till in its per- fect ftate, but patting through all its changes in it. Reaumur- Hilt. Infect. Vol. 6. p. 16.

Grapes, in the manege, is ufed to fignify the arrefts, or mangy tumours that happen in a horfe's legs. See Arrest.

GRAPHIDA, in natural hiitory, a name by which fome au- thors have called the ?mrochthus, or French chalk. IVorm. Muf. p. 71. See the article Morochthus.

GRAPHISCUS, in the writings of the antients, a name given to an inftrument ufed for the extracting darts from wounds. It is faid to have been the invention of Diodes, and is de- fcribed by Celfus.

GRAPLINGS, inafhip. See Grapnel.

GRAPNEL, on fhip board, a kind of anchor for boats or gallies to ride by. It differs from other anchors, as having four flukes and no fnack, though there are fome with three flukes, with which they ufe to fweep for hawfers or fmall cables. In men of war alfo, the grapnels, or at leaft a lighter kind of them, are ufed to be thrown into an enemy's fhip, in order to catch hold of fome of her gratings, rails, gun- wales, &c. this is done in order to boarding of her.

GRASS {CycL) — The Englifh grafs, when good in its kind, is much fuperior to that of all other nations, and in our grafs plats, and turfed walks, our gardens excel thofe of all the world.

The common way of making thefe is by laying on turfs from a common, and the plats thus made are greatly fuperior to thofe made by lowing, there being great nicety and art re- quired in bringing the latter to good order, and in the pro- curing the proper ked, that from common hay-lofts beino- of a mixture of good and bad kinds, and by no means fit for the purpofe, as containing the feeds of weeds, as well as very improper graJJ'es.

In order to fow grafs, the ground mutt: be dug up with the fpade, then finely and evenly raked over, all the clods and ftones taken off, and an inch thicknefs of good mould fiftcd on to facilitate the growing of the feed. This done, the feed muft be fown very thick, that the blade may come up clofe and fhort ; and the ground muff be then raked over again to bury the feed, otherwife, if it inould happen to be windy weather, a great part of it may be blowu away.

The beft feafon for fowing of grafs is the latter end of Au- guft, and it is beft to fow it in a mild day, when there is a likelyhood of rain. When it is come up to any height, it muft be mowed, and this repeated very frequently, for the oftener it is mowed, the thicker it grows. It mould be rolled alfo frequently with a wooden roller. In autumn, wherever there are naked patches, the ground ttiould be fown With frefh feed. Miller's Gard. Diet.

EverlajUng Grass, a name given by fome of our farmes to the plant more properly called faint foin. It fcrves as grafs for the food of cattle, and dries into hay ; and a crop of it once well rooted in the ground, will continue forty years without renewing. See the article Saint -/«'». Rey Grass. See Rey grafs.

GRASs-bearth, in our cuffoms, grafing, or turning up the earth with a plough. Hence the cuftomary fervice for the in- ferior tenants of the manor of Amerfden in Oxfordshire, to bring their ploughs to do one day's work for their lord, was called grafs-hearth^ or grafs-hurt. Kenn. Paroch. Antiq. p. 496, 497.

Grass