Page:Cyclopaedia, Chambers - Supplement, Volume 1.djvu/65

 A G A

A G A

of itfelf, but that fort of rotten wood, which we call touch-i wood, and which often Ihincs like fire in the night; a pro-' perty that no fungus has. This Alining rotten wood is com- mon in many places ; and as it is not to be dtftinguiihed from other rotten wood by day-light, thofe who were of opinion that it contained any peculiar medicinal virtues, were in the right to have it collected in the night. The female Agaric of Diofcorides feems to have been this fubftance ; for he dc- fcribes it as being of a fpungy texture, and having {trait fibres, which this rotten wood always has. The oak, and other glandiferous trees, are alfo moil remarkable for producing this touchwood ; though the larix is the tree which produces the Agaric. The fhining of this wood, when in its rotten flate, is accidental, not being always found in it, Mineral Agaric, Agaricus mi/ieralis, in natural hiftory,. the name of a light, fpungy, marley earth, called by others marga Feroenjis, and lac lima, and by the antients terra, or creta Seleneufiaca. It had its anticnt name. from the city Selinus in Sicily, near which it ufed to be found in great abundance ; and its more modern one from its refemblanqc to the vegetable Agaric, in its lightnefs, colour, and fungofe texture. .*"

It is an earth fubje£t in itfelf to various admixtures, and mix- ing itfelf with various other bodies : - it is, .however, generally found pure, and is then abfolutely the fame in all parts of the world. ,

It never conftitutes of itfelf a ftratum in the earth, but. is Found in the perpendicular fiflures of the il.rata of ftone.s, and in a thoufand imperceptible cracks in them ; at which the maflcs naturally break, and difcharge, this matter from them, in form of a white powder. It alfo fometimes lines the roofs of caverns, and fometimes lies, like the terra Samia, in large quantities, in the horizontal vacuities of. thefe ftrata. In thefe feveral places it is found, either in irregular maffes, of a fine and pure white colour, porous, friable, and ftain- ing the fingers, and adhering firmly to the tongue ; or elfe in fmaller, and fomewbat firmer maffes ; or, Iaftly, in a dis- continuous flate, or in form of an impalpable powder, of a pure fnow white. . (.

Mineral Agaric ferments violently with acid menftrua, and diffufes immediately in water. It is often found itaincd with adventitious particles of other earths, &c. and is then altered in colour, and found brownifh, yellowifh, or reddifh; and is frequently received into the bodies of other foffils, being very probably the moil frequent debating earth of cryftal. V. HiW& Hiftory of Foffils, p. 49.

Some fuppofe mineral Agaric to have been known to the an- tients ; and that it is the fame with what they call morotihus, and galaEtites.

Formerly Switzerland was the only country known to produce this mineral ; but, of late, it has been difcovered in the terri- tory of Nuremberg. Something very much like it has been obferved among the flones near Rouen in France. V, Ephem. Germ. cent. 1. obf. 2. p. 5. Jour, des Scav. T. 43. p. 381. feq.

It is ufed internally againft hemorrhages, the ftrangury, gra- vel, and efpecially dyfenteries ; externally, to dry and heal old ulcers, flop defluxions of the eyes, &c. Lang. Idea Hift. Natur. Lapid. Figur. Helvet. c. 3. in Ephem. Germ. dec. 3. an. q. app. p. 211. feq. AGARICUS, in theLinnaean fyftem of botany, the term ufed to exprefs that genus of fungus's, which have no pedicle, but grow to trees, fcfe. by one fide, and are therefore called horizontal fungus's, and are lamellated underneath : by. this laft character they are diilinguifhed from the Boleti of Lin- naeus which are thofe horizontal fungus's which are porous underneath. AGASYLLIS, in the materia medica, a name given by fome of the antient Greek writers, to gum ammoniac ; and by others, to the tree which produced that gum. By their de- fcriptions of this medicine, it appears not to have been the fame which we now know by this name. AGAT ( Cycl. ) — The Agat is a peculiar and very exteniive genus of the femi-pellucid gems. The characters of which are, that they are variegated with veins and clouds, but have no zones, like thofe of the onyx. They are compofed of cryflal, debafed by a large quantity of earth, and not formed, either by repeated incruftations round a central nucleus, or made up of plates laid evenly on one another, but arc merely the effect of one fimple concretion, and variegated only by the difpofition the fluid they were formed in gave to their diffe- rently coloured veins, or matters.

Thefe are a very numerous genus of foffils, and fubject to great variegations in their colours. They are, however, ar- ranged into fome order, according to the different colours of their ground.

Of thofe of a white ground, there are three fpecies. 1. The dendrachates, or Mocoa-jlone. See Dendrachates. 2. The dull milky-looking Agat. This, though greatly in- ferior to the former in beauty, is yet a very beautiful ftone. This is common on the fhores of rivers in the Eafl-Indies, and alfo in Germany, and fome other parts of Europe. Our lapidaries cut it into counters for card-playing, and other toys of fmall value. 3. The lead- coloured Agat, called Suppj,. Vol. I.

the pbajfachates, by the antients. See the article Pi-iassa- chates. . ,

Of the Agats with a reddifl) ground, there are four fpecies> 1. An impure one of a flefh coloured white.; This is of but little beauty, in comparifon with many other Agats. The admixture of flefh colour is but very flight, and it is often found without any clouds, veins, or other yariegations ; but fometimes it is prettily veined, or variegated with.fpots of ir- regular figures, with fimbriated edges. It is found .in Ger- many, Italy, and fome other parts of Europe, and is wrought into toys of fmall value, and often into the German gun- flints. It has been found, fometimes, with evident large Spe- cimens of the perfect: mofles bedded deep in it. 2. The fecond of the red grounded Agats, is that fpecies of a pure blood-colour, called h&machates, or the bloody Agat, by the antients, See H^machates. 3. The third is the clouded and fpotted Agat, of a pale flefh colour, called the carnclian Agat, or far dacbates, by the antients. See Sardachatf.s. 4. And the fourth, the red-lead coloured one, variegated with yellow, called the coral Agat, or corallo-achates, by the an- tients. See Corallo-Achates.

Qf the Agats with a yellowijb ground. There are only two known fpecies. 1. The one of the colour of yellow wax, called ceracbates by the antients. 2. The other a very ele- gant ftone, of a yellow ground, variegated with white, black, and green, called the leonina, and leonteferes, by the antients. See Leontese-Res.

Laftly, of the Agats with a greenifb ground. There is only one known fpecies, which was the jafpachatcs of the an- tients. See Jaspachates. Hill's Hiftory of Foffils. Some have attributed great medicinal virtues to the Agat ; as, to refill poifon, efpecially thofe of the viper, the fcorpion, arid fptder; to appeafe thirft, ftrengthen the fight, and I know not what. Plin. Cajlcl. Lex. p. 8. Ruland. Lex. A.lchem. p. 2.

Oriental Agats are fatd to be all brought from the river Gam- bay. Hamilton, Account of E:\ft-lndia, c. 13. Pref. State Rep. Lett. T. 2. p. 171.

A mine of. .^gy^j. was lately difcovered in Tranfilvania, of divers colours, fome of a large fize, weighing feveral pounds. Ephem. Germ. cent. g. p. 427.

Agats have been diilinguifhed by other names, than thofe be- fore mentioned. Thus we find Vermilion Agat, that of a deep vermilion colour. This, in the text of Pliny, is called Achates unlus coloris, which fome correct by minii coloris. Hardouin prefers the antient reading. V. Hardouin, Not. ad Plin. 1. 37. c. 10. White ringed Agat, Achates perileucos, diilinguifhed by black and white circles a. Plott mentions this under the denomi- nation, of crow-Jlone b, — [ a Salmaf. ad Solin. Polyh. p. 94. t- Plott, Nat. Hift. Staffordfh. c. 4. §. 47. p. 175.] White Agat, leucachates, that altogether white, or at lcafl diverfified with white ftrokes, being frequently femi-tranfpa- parent, and bearing a refemblance to the white of an egg. Vitreous, or tranfparent Agat, of a thin ftone-blue colour. Leopardlne Agat, Achates pardalios, fpotted like the fkin of a

leopard. This is otherwife called pandalion, pantachaUs.

Sappbirlne Agat, that of a fky-blue colour, tranfparent;

fometimes found with lapis lazuli, and called alfo fapphiro-

achates.

Luminated Agat, diilinguifhed by divers colours, as white,

black, yellow, brown, placed over each other, at equal di-

ftances. 1

Agats are alfo divided, with regard to the objects reprcfented

on them* into Arborejcent Agat, dendrachates, See Dendrachates and Dendrites.

This feems to be the fame with what fome authors call the Achates, with rofemary in the middle, and others, Achates* with little branches of black leaves. Borricb. Act. Haf. 1677. p. 206. Homed Agat, ceracbates, is faid by fome to be that which, by lines and fpots, reprefents the figure of a horn a. Others explain the ceracbates to be that fpecies which has a waxy furface \ The difference arifes from the etymon of the word. The former fuppofes it formed from the Greek, xE?a;, cornu, horn ; the latter from the Latin, cera, wax. — [ a Worm. Muf. p. 90. b Salmaf. loc. cit. p. 94. feq.] Aphrodijian Agat, Achates aphrod'tfius, is a term given by Velfchius to an Agat in his cuilody, of a flefh colour, on one fide of which appears a half-moon, in great perfection, reprefented by a milky femicircle ; on the other fide, the phafes of Vefper, or the evening ftar ; whence the denomi- nation aphrodijius. Ephem. Germ. Dec. 1. an. 1. obf. 156. p. 296. Corfoid Acat, reprefenting human hair. Salmaf, Exerc. in,

Solin. p. 539. Aritlmieiical Agat, reprefenting the numbers 4191, 191.

V. Settala, Muf. 81. AJlronomical Agat, reprefenting the hemifphcre, with its fe- veral orbs, and the earth in the middle. To which head may be alfo referred an Agat mentioned by Borrichius, reprefent- ing the five orbs in great perfection. Act. Hafn. 1677. p. 208. -

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