Page:Cyclopaedia, Chambers - Supplement, Volume 1.djvu/135

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With blue. All of them are very glofly, and extremely fmooth to the touch. Its feet are fcarce thicker than hogs briftles. It is generally efteemed a poifonous animal. Ray,, Syn. Quad, p, 267. See Tab. of Quadrupeds and Serpents. N°. 35. AMETHYST, (CycL) the name of a very well known and very beautiful gem. The ftone called Amethyfi by the antients, was evidently the fame with that now generally known by this name, which is far from being the cafe in regard to fome of the other gems. And the gem they called the hyacinth was alfo no other than a variety of this flone, refembling the Mower of that name. See Hyacinth, They accounted, befide that alfo, five other fpecies of the Amcthyji, all which were truly no, more than varieties of this fioiie in the degree of colour, and all which, we alfo have at pre- fent, though not known among our jewellers under any par- ticular names. Indeed there might be numberlefs names and numberlefs fpecies accounted of this gem, if they were to be given according to its different degrees of colour, it having fomctimes a bluer, fometimes a redder purple, and varying in degree through all the changes between the colour of the ripe purple grape, and the colour lefs hue of thepureft cryftals. It is inferior to fcarce any of the gems in beauty, and in the fined fpecimens is of the fame hardnefs and of equal value with the ruby. It is found of various fixes, from the big- nefs of a fmall vetch to an inch and half in diameter, and often to much more than that in length. It is as various in fhape as the diamond, and fome other of the gems; it is not unfrequently found in a round ifh or pebble-like form, fometimes a little longifli, and often thicker at one end than the other, and refembling in fomc fort a pear. It is in thefe ftapes fometimes equally rounded every way, but more fre- quently it is flatted on one fide, and often has very fmall and very bright faces on feveral parts. Tho' this is no unufual form to meet it in, its more common appearance however is a cryftalliform figure, being found adhering by its bafe toftony matter, and either crufting over the cracks and fiflures in the flrata of ferrugineous ftones, or coating the infides of large and hollow ferrugineous nodules, refembling thofe hollow flints which we every day fee in England, coated within with common fmall pellucid cryftals. In thefe nodules the Amethyfi always afllimes the form either of a fhort and thick column of four planes, terminated by a flat and fhort pyramid of the fame number of fides, or elfe the very figure of our common hex- angular cryflal, and fometimes that of a long pyramid without any column adhering to the matter of the nodule by its bafe \ in the columnar fhape it makes the gayeft figure, but in the' pebble-like manes it is always the hardefl and moll valuable.. Hill's Hift. of Fof. p. 593.

The colour of the Amethyfi is ever purple tho' various in de- gree, fometimes approaching to the violet colour, and fome- times fading almoft into a rofe colour. It is fometimes alfo found naturally colourlefs, and may, at any time, be made fo, by putting it into the fire j and whether it has been naturally, or thus artificially produced, it, in this ftate, fo nicely imi- tates the diamond, that its want of hardnefs feems the only way of diftinguifhing it.

The tips or points of the angular Amethyfis are often the only coloured part, the reft of the column remaining white.

The Amethyfi is found in the Eaft and Weft-Indies, and alfo in Europe. Some of the oriental ones, efpecially of the pebble kind, are very hard, and of a very great fplendour and value } but thefe are rare, moft even of the oriental ones being very little harder than common cryftal ; and all the European ones are of this foft kind : whence the Amethyfi, in general, is of much lefs value than moft of the other gems, though a few fpecimens of it are very valuable. The oriental Atnetbyfis are found in Calecut and Bifnagar. The European ones are common to many places ; Germany, Silefia, and Bohemia abound with them j and they are not uncommon in Spain and Italy ; the Pyrenseans, and the mountains of Auvergne afford very fine ones, and the mountain St. Sigi- mont in Catalonia is dug in many places for them. They there find the fineft lodged in the perpendicular fiflures of the rock, among a loofe reddifh ferrugineous earth. M. Morin fliewed Dr. Lifter a huge block of French Ame- thyfi, % or 300 pound weight a. Ray fpeaks of a mountain of Amethyfis »>._£» Vid. Lift. Journ. Parif. b Ray, Trav. p. 4.69.

Amethyfis may he counterfeited with glafs, to which the pro- per colour or ftain is given. There were fine ones made in France, about the year 1690, which may even impofe on connoifeurs, unlefs the ftone be taken out of the collet. The method of giving this colour to glafs is as follows. Take cryftal-frit, made with the moft perfect and fine tarfo j then prepare a mixture of mangancfe in powder, one pound ; zaffer prepared, one ounce and half; mix thefe powders well toge- ther, and add to every pound of the frit, an ounce of this powder. Let it be put into the pots with the frit, not into the already made metal. When the whole has flood long enough in fufion to be perfectly pure, work it into veffels, and they will refemble the colour of the Amethyfi, Neri's Art of Glafs, p. 92.

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Some pbyficians make a particular clafs of medicines, We, the denomination o! Ametby/la, A^ r * ; under v, hl ^ h th comprehend all prefervatives from drunkennefs. Vid Gal de Compof. Medic, fee. loc. c. 2. Gorr Def Med n* is '

AMETHYSTINE is applied, in antiquity, to a ktd'oFpufpIc garment dyed of the hue of Ametbyjt. Pirn. Htfl Nat T. I. 1. 9. c. 38. p. 526. feq. In this fenfe, Amethyjltne differed from Tyrian, as well as from

a-vT^'r » pUrple ' bein g a kind "f medium between both.

AMGA1LA, or Amgailam, in the materia medica of the antients, a name given, by Avifenna and others, to a plant fometimes called acantlm Arabia,, and kucacantba by the Uretks ; the roots of which were called bunkan, and much ufed in medicine by the Arabian phyhcians. The names of this plant were almoft all common to it, and to the tree which produces the gum Arabic ; and hence arifes a areat confuhon in reading the works of thofe who name it But It is very certain, that they are two extremely different vege- tables, the one being a tree, and the other a plant, whofe roots w-ere ufed m medicine.

The Amgaila, called alfo fucaba, or zucahai, is defcribed as a prickly herb, having roots like thofe of the Cyprus, formed ot lcyeral joints, or knots ; and that thefe, when they had been fo long expofed to the air as to he, in fome fort, rotten, and to fall fpontaneoufly from one another, were afterwards dried, and became very light, of a yellow colour, and agree- ably aromatic fmell, and bitter taftc. They were ufed in tomachic and cardiac compofitions, and were chofen by their ligbtnefs and good fmell. AMIA, in zoology, the name of a very large fea fifh, called by fomc alfo glaums, and by others Uccia. It grows to a yaft fize, and in figure refembles the falmon. Its body is long and thick, and becomes fquare towards the tail. Its back is of a dufky blue, with a light tinge of purple. Its fides are ot a more purple hue. It is covered with confiderably large (ales, though they feem fmall, when we compare them with the uze of the fifh. Its mouth is not large ; its jaws are fur- rufhed with fharp teeth. Its gill fins are very fmall for its fize ; its belly fins are placed near thefe. It has alfo two on the hack; the anterior has feveral very fharp prickles; the pofterior is long, and reaches almoft to the tail : this and the belly fin oppofite to it, are undulated at their edges. The tail is very forked. It is very common in the Mediterranean^ and grows to four or five feet long. Saliiian. de Aquat. Aldrovani, de Pifc. p. 302. Amia is alfo the name of a fifh called, by fome authors, ft- lamys, but different both from the pelamys farda, more ufually called fimply pelamys, and from the pelamys of the antients, which was no other than the tbynr.us, or tunny-fifh, at a cer- tain time of its growth.

This is, in fhape and figure, very like the mackrel, long, round bodied, and flender near the tail ; the back is of a dufky blue, the belly of a fine filvery white, and its fides are variegated with eight or nine oblique black lines. Its jaws have only one row of teeth in each. Its eyes are fmall. It & common in the Mediterranean, and is brought to the markets of Italy, &c. Ray's Ichthyograph. p. 180.

AMIANTHUS, in natural hiltory, the name of a genus of foffils, of the clafs of the fihraria ; the cbaraflers of which are, that the bodies of it are flexile and elaftic, and compofed of fhort and abrupt filaments. See Tab. of Foffils, Clafs 1. It has been a common error to confound the fpecies of this genus one with another, and all with the feveral fpecies of the afbeflus, the confequence of which has been the lofs of the art of fpinning and working the afbeflus into incombuftible cloth. See the article Asbestus.

The fpecies of this genus, at prefent known in the world, are four, two of which are compofed of larger, and two of finer or fmaller filaments.

The firft is a reddifh black kind, with very fhort threads. This is very common in the iron mines of Germany. 2. A foft, filky, white kind, with fhort and crooked filaments. This is found in many parts of France and Germany. The fecond kinds are, I. A greyifh green, rigid one, called erroneoufly alumen plumofum in the fhops. This is found in Egypt, Africa, and Germany. And, 2. A greenifh .brown one, found in maffes of ftone in Yorkfhire, and in Wales and fometimes in the fame green marble at Anglefea, in which one of the albefti is often found. Hill's Hift. of Fofi'. p. 108, 109, no.

AMICABLE bencbes, fcamna amicabilia, in antiquity, are ge- nerally fuppofed to denote the feats in the Roman courts* whereon the advocates were placed. — Some think, that thefe had but little title to the denomination of amicable^ and therefore will have the word to be here ufed fur the benches whereon the ajfejjbrs, or thofe called judices pedanei, were placed. Pitijc. Lex. Antiq. in voc.

Amicable compounder, amicabilis compofitar, is ufed, in fome antient law writers, for an arbitrator. X)u Cange^ Gloff. Lat. in voc. See Arbitrator, Cyel.

AMICITIA — Tenure in Amicitia, tenere in Amicitiam, is applied, in antient writers, to lands granted freely, and of mere good-will, to be enjoyed at the difcretion of the donor. Dtt Cange, Gloff. Lat. T. 1. p. 168.

AMICTUS