FER
fembling To many plants of the common unbranched fern, fending out a great number of regular leaves on each fide the ftem. Thefe ramifications of the fait, will remain many weeks in this perfection if the veflel "be not ftirred ; but they are fo tender, that the leaft motion deftroys them, and they after this, never will form themfclves again* Phil. Tranf. N°. 105.
FeRN-«7, in pottery, a name given by our merchants who have been in China, to a fort of varnifli, which the Chinefe ufe in their porcelain, manufactories. It is alfo called lime-oil, and is a thing fo ealily made, that it would be worth attempting what might be done with it, in our imitations of the porce- lain. They make it in this manner; they take a large quan- tity of fern well dried, and fpreading a covering of it over a piece of ground fufficient for the quantity of oil they intend to make, they lay upon this a coat of large lime-Hones, new- ly calcined into lime ; on thefe they fprinkle with the hand a fmall quantity of water juft to flake them. They cover this bed of lime with another of fern, and fo on, till they have raifed it to eight or ten foot high ; they then fet fire to the fern, this burns away in a little time, and leaves a mixture of the lime and its own aihes. This mixture is laid in the fame manner between beds of more fern, and burnt again. This operation is repeated five or fix times. Obferv. fur les coutom. de 1'Afie.
When the laft calcination is finimed, the mixture of lime and afhes is carefully gathered up and thrown into large veiTels of water, and with every hundred weight of it, they put in one pound weight of kekio; they ftir the whole together, and when the coarfer part has fubfided to the bottom, they take ofF the finer which fwims at the top in form of a fine cream, and putting it into another veflel of water, they let it fubfide to the bottom by long {landing ; they then pour off the wa- ter and fave the refiduum in form of a thick oil. This they mix with the oil of ftone, prepared by powdering and wafhing in the fame manner a particular fort of (tones, and with this they cover all the veflels that they intend to varnifh. The fern alhes have a very great fliare in the ad- vantage that this oil has over our common varniihes ; and the Chinefe tells us, that they once inftead of fern ufed the wood of a tree, called fe tki, and they fuppofe that the fupe- rioiity of the old porcelain over the prefent, is owing to the ufe of this tree inftead of the fern ; but is now too fcarce among them. The new manufacture which we have at Brif- tol, excels every thing that has been done of the like kind, in the b.-auty of the varnifhing ; and it is faid, they have founded their advantage on an imitation of this, and the Chinefe oil of (tone. Thefe two oils, as they are called, are always mixed together, and they muft be carefully preferved of the fame degree of thicknefs, or elfe all the varnffliing will not be even.
FERN-r<wr, was frequently prefcribed by the antients in diet- drinks, for removing ob ft ructions, and in chronic cafes of all kinds ; but it is much difufed at prefent. The country peo- ple, indeed, cfteem it a fovereign remedy for the rickets in children ; they alfo give it in powder to deftroy worms.
FEROEN5IS marga, in natural hiftory, a name given by fome authors to a marley earth, found principally in the fiflures and cavities of ftone, and called by the generality of later naturalifts, agaricus mineralis, and lac hunts, and by the an- tients, terra or cfeta fekneufiaca. Hill\ Hift. of Foil" p. 48. Charlton of Fo(T. p. 48. See Lac Luna, Cycl. and Suppl.
FERRA, in zoology, the name of a fifli, called alfo by fome guhuad, and caught both in the lakes and rivers. It is of the truttaceous kind, and is ufually of a foot or a little more in length, and in the (hape of its body much re- fembles the filmon. Its back is brown, its belly white, its fcales are of a moderate fize ; its upper jaw hangs a little over the under, and its mouth is very like that of the common herring ; it has no teeth, the belly is fome what flatted, not running to an edge, the top of the head is of a faint blue, full of dusky fpots ; the eyes are very large, and there is on each fide a ftrait line running from the angle of the gills to the tail ; the tail is forked. It is a very well tafted fifh, and ufually is feen fwimming in large fhoals. Pimble-meer in Me- rionethihire, is the place where the greateft quantities of it are taken, but it is alfo caught in Cumberland, and fome of the northern counties of England, and called there the fchel- ley. IFilbughbyh Hift. Pifc. p. 183.
FERRARIA, in botany, a name ufed by fome authors for acri- mony, and by others, in particular by Lobel, for the fcrophu- lan'a, or fig-wort. Ger. Emac. Ind. 2.
FERRET, viverra. This creature has but one note in her voice, which is a fhrill, but fmall whining cry. The female ufually brings forth feven or eight young ones at a time ; fhe carries them in her body forty days ; the young ones are blind for a long time after they are littered. When they are tamed they are to be fed with milk, and with barley- bread ; they will fait a long time j when they walk they fet up their back, which is otherwife fo long, that it would be troublefome to drag it on ; when they are touched they fmell very difagreeablv ; they naturalyfleep very much. The ferret is a bold and' audaci- Su ppl. Vol. I,
FER
ous animal, and is an enemy to almofl all other., It do-s r.o* Wu fle<h ° f the creatures " kills > but fucks their blood. When the warrener has occafion to ufe the ferret to catch rabbets, he firft makes a Itoife in the barren to frighten them all into their holes, then he pitches his nets, and having muiiled the ferret that he may not bite the rabbets, he turns him into their holes to frighten them out, and then the dogs drive them into the nets that are fet for them. See Viverra. Ferrets, in glafs making, the irons with which the workman tries the melted metal to fee if it be fit to work. It is alfo ufed for thofe irons which make the ring at the neck
toddi NC "' S A " ° f Glafs ' A PP="*'*-
fERRM ES d' Efpagrc, in natural hiftory, a name eiven by authors to certain {tones of a regular figure, fdund on' the fides of a rock in Spain ; and, as has been fince difcovered, very plentifully on the bottom and fides of the Fontaine de Safut near Bagneres in France, and in other places in the country thereabout. In the firft bath through which the largefl of the two branches of this fpring flows, there are found at different times great numbers of thefe ferretes : they are fmall (tones of the colour of rufty iron, and of a regular figure, being either parallelopiped with oblique angles, "of which the fides are unequal, or fmall folid bodies with fix fides, only differing from cubes or dice in this, that the furfaces are not perfeflly per- pendicular to one another, but a little inclined ; they are alio commonly longer than they are broad, and broader than they are high. The largefl of thefe fall fbort of an inch in mea- fure, being about eleven lines in length, nine and a half in breadth, and fix in heighth, but they are ufually a great deal fmailer, and are fbmetimes found in duffers, a hundred or more together; and fome of them have {hilling skins feeming of a metallic fubftance. Thefe {tones arc not only found in the bath, but in the digging a way for a common road, from the town of Bagneres to it, they were found lodged in their pro- per ftratum. The workmen here met with a bed of a fbft kind of flateofa bluifh colour, but lighter than that of the common Hate. The whole rock they worked through, Was compofed of layers or beds of this, lying almoft parallel over one another. The fubltance of the flate feemed to be a com- petition of fibres or firings, laid regularly fide by fide, by one another, and all equally inclined" to their beds or layers. Whence it comes that upon breaking them with a hammer! the pieces fometimes are pretty like the figure of a regular pa- rallciupiped with oblique angles. Upon a narrower examination of this fort of (late, there are ufually found in it, a great num- ber of parallelopiped (tones, like thole before fpoken of, only fmailer ; and feveral little black fpots difcovered in other parts of the (tone when they are examined with glaflis, prove al- fo to be regularly figured bodies of the fame kind. Every one of thefe Hones fo long as it remains in the rock, is always found between two bundles or clutters of tranfparent fibres, of which generally one is placed on the one, and the other on the oppofite fide; thefe clutters of fibres are largeft in the largeft (tones, however they are always found even a- bout the fmalleft in fome quantity.
In fome of thefe {tones, the tranfparent fibres of which every clutter is compofed, have left a vacancy in the middle of themfclves ; this Ibrt of liflure being coloured with a fer- rugineous matter, and now and then with metallic and (tim- ing veins, it is not a very improbable conjecture, that the ufe of the tranfparent fibres is that of (trainers, which flitter nothing to pals through them to the little (tones, but filch particles as are proper to advance their growth. In pieces of a harder (late near the fame place, there are alfo frequently found fmall (tones of the fame figure but of a brafl'y colour, thefe alfo are attended with the like clutters of tranfparent fi- bres. Philof. Tranf. N ; . 472. p. 30.
Great quantities of ferrugineous (tones are alfo found in lar»e mattes in all the rocks about the fountain de Salut ; and it°is very probable, that the water of this fpring, runs through a bed of this fort of foft flate before defcribed, in which thefe regular (tones are lodged, and from which it may very eafily loofen and detach them in its paflage, and fo bring them alono- with it. The bundles of tranfparent fibres are fattened very firmly to the flate, but very (lightly to the ftone that they furround ; whence it is very evident, that if thefe (tones are thus detached by the water, they muft come alone, not with that matter joined to them.
FERRETTO, in the glafs trade, a fubltance which ferves to colour glafs. This is made by a fimple calcination of copper, but it ferves for feveral colours. There are two wajs of mak- ing this : the firft is this, take thin plates of copper, and lay them on a layer of powdered brimftone, in the bottom of a crucible, over thefe lay more brimftone, and over that an- other layer of the plates, and fo on alternately, till the pot is full. Cover the pot, lute it well, place it in a wind fur- nace, and make a ttrong fire about it for two hours. When it is taken out and cooled, the copper will be found fo calcin'd, that it maybe crumbled to pieces between the fingers, like a friable earth ; it will b= of a reddifli, and in fome parts a black- ifh colour. This muft be powdered and fitted fine for ufe. Neri's Ait of Glafs, p. 30.
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