Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/160

 ORE

ORE

greatcft meadow- palmated orchis. 66. The lefTer palmated orchis, with long (purs to the flowers. 67. The fmall narrow- leaved fweet-fcented palmated orchis. 68. The clove- i'cented palmated orchis. 69. The_ white-flowered palmated orchis, with the fmell of elder. The purple-flowered palmated orchis, with the fmell of elder. 71. The palmated frog or- chis. 7 1 . The caftrated orchis. 73. The broad-leaved mariii palmated orchis. 74. The narrower-leaved palmated marfli orchis. 75. The common palmated marfli orchis, with very narrow leaves. 76. The palmated marfli orchis^ with fpotted leaves. 77. The palmated marfli orchis, with red leaves and flowers. 78. The green-flowered palmated or- chis. 79. The largeft palmated orchis, with a bright-red fweet-fcented flower. So. The greateft palmatcd mountain orchis. 81. The narrower leaved great palmated mountain orchis. 82. The white-flowered palmated mountain orchis, with fpotted leaves. 83. The narrower-leaved palmated al- pine prcHs, with a black flower. 8|. The narrow leaved palmated mountain orchis, with rofe-coloured flowers. 85. The narrow-leaved palmated mountain orchis, with white flowers. Town. Inflr. p. 443

Orch r s-r<?«", in the materia medica, is otherwife named falep, vulgarly called fa loop. See thearricle Salep.

Orchts, in ichthyology, a nam.? ~iven by Gefner, and fome others, to the fifh, commonly called orbis, and by Artedi the fpherical ojhacion, with four teeth, and fmall fpines all over it. See the article Ostacion.

ORCHOTOMY, a word tifed by fome chirugical writers for the operation of caftration.

ORCYNUS, in zoology, a name by which fome authors have called the fifli commonly known by the name of the tunny or thynnus. Wilkughby% Hiflr. Pifc. p. 176, See Thynnus.

ORDER, in rhetoric. See. Disposition, Cycl.

ORDINARY (Qk/.)— Ordinary Court of Chancery. See Petty bag.

ORDINATE (Cycl)— To find the greateft and leaft ordinate to curves. See Maximum, Cycl. & Suppl.

ORE (Cycl.) — Some em are fo kindly as to melt readily of themfelves, without any affiftance from the common fluxes; thefe are of great value to the owners Other are more in- tractable and require the aiTiftance of various fluxes, and others fo very obftinateas not be work'd in the larger way, where there can be no very considerable expence allow'd for fluxes. On this account many mines remain at this time unwrought, as being untraceable in the large way without great charges ; hence the improving the bufinefs of fluxes ferves to render them at once both cheap and effectual, and mult be of great fervice to metallurgy.

Some of the cheapeft and mod powerful fluxes now in life are dry'd wine lees, dry'd cow-dung and horfe-dung, dry'd ' river-mud, fuller's- earth, iron filings, common fait, potafli, and fandiver. Thefe may be nfed in the larger works, as nitre, tartar, borax, fal armoniac, and mercury fublimate in the lefs : as for compound fluxes they are very numerous, al- moft every operator having his particular noftrum ; and it is plain that fome fluxes are better adapted to the ores of fome metals than others ; but certainly a few general ones might be fixed upon, one or other of which would anfwer all the ope- rator's expectations.

The following three preparations are all very -general, very powerful, and not expensive. 1. Take of nitre, prepared by long boiling in lime water, of fea-falt melted in the fire, of fandiver, and of dry wine lees, each one part; glafs of lead three parts, and powdered glafs eight parts; mix them all well together, and ufe them in a'n equal weight with ftub- born ores. %. For a ftill ftronger flux take equal parts of white tartar, common fait, and nitre prepared as above ; cal- cine all together to a white powder, and mix with it its own weight of glafs of lead ; of this flux add two parts to one part of the mod ftuhboin ores. 3. For every powerful faline flux, take of the ftrongeft foap- boiler's lees four pounds, of white tartar and common fait, melted in the fire, each one pound, boil thefe together, with four gallons of human urine, to a dry fait. This flux is particularly ferviceable where fulphur and cobalt abound, and render the ore very refrac- tory. Shaw's Lectures, p. 257.

The ores of the richer mctals,as gold and filver,ufually contain a very confiderablc portion of fulphur, and Alonfo Barba tells us, that the m oft expert mineralilts in Peru, always efteema- bundance of fulphur a fign of a rich ore in the neighbourhood. Among the richeft ores of the mountain of Potofi, there are fuch quantities of native brimftone, that the cavities in the mines arc often filled with a blue flame, on only bringing a lighted candle into them fo as to touch their fides. It has been wondered at, that where there is abundance of fulphur in thefe mines, there fhould be no vitriol found, that being only ame- taldiflblred by means of fulphur; but this objection ceafes, when we conadcr the denfe and compact nature of thefe two metals, which renders them not foluble by means of fulphur, as the others are. Wherever there is ftore of fulphur, or of pyrites, or other ftones which contain fulphur in the mines of copper and iron, great ftore of vitriols are always found there alfo, being formed by the corrofion of the ores of thofe metals by fulphur, which renders them foluble in water, from which

they again concrete in form of falts. Chemifrry is -ablc'to Imitate the operations of nature on this occafion feveral ways ; for cop- per* or iron, being formed in thin plates, and either rubbed 6- ver with the acid fpirit of fulphur, or calcined with powder' of common fulphur, become foluble in water, and afford cryfrals of true vitriol wholly analogous to the natural ones, and either blue or green, as iron, or copper are the metals employed 5 but thefe procefles not being able to produce cryftals of fait, or vitriol, from either filver, or gold, it is not wonderful that nature is not able to form them by the fame means. The general formation of fulphur from the ores of metals yet lying in the bowels of the earth, is, probably, after this man- ner. An acid, (aline, fulphureous fteam, or vapour, fuch as common fulphur is eafily reduced to, by heat not greater than, that within the bowels of the earth, infinuating itfelf either through the pores of ftones, or through their cracks, which are always frequent about the veins of metals, penetrates into the bed of ore; fuppofe of copper. The vapour is continually fupplied with frcfli quantities from below ; and as it blends it- felf with the metal, corrodes it as the fume of brimftone will the fame copper in plates. The metal, thus corroded, being foluble in water ; as we find by experience, it is neccflary, that the w^muft, under the fame management, be fo too ; and, in tins cafe, the water, which is continually pervading all the ftrata of the earth, waflies off the diffolved metal ; and where- ever it happens to be ffayed in fmall quantities afterward, whe- ther within the vein of the metal, or at a diftance from it, it cryftallizes the fait it contains, and common blue vitriol is produced, if the metal in the vein be iron. The fame procefs is obferved, and the event is the fame in all refpefis, when copper is the metal corroded, except that the vitriol, inftead of blue, is green ; this plainly accounts for the obfervation of the workers in copper-mines, that vitriol and brimftone are ufualfy found together, the one being a natural confequence of die other. Sulphur is, indeed, often found where there is no vitriol, but vitriol is very feldom found without fulphur; it beim* not a diftinct principle, but a genuine production of ful- phur. Phil. Tranf>N° 104.

Drejjtng of 'Ores. Seethe article Dressing.

Iron Ore. See Iron.

Gold Ore. See Gold.

firm, Pottern, and Steel Ore. See Lead ore.

OREILLARD, in the manege. See Wmz-eared.

OREJUELAS, in botany, a name ufed by fome authors for the jlos auricula, a flower growing in New Spain, and ufed there in making chocolate. Dale, Pharm. p. 339.

OREON, a name given by the antients to a kind of horfe- tail, which they found growing on the mountains in wet and damp places. It is to this fpecies that many authors have attributed the principal virtues of the genus ; and this feems to have been the fame with our great water horfe- tail. Neophytus fays, that it rofe up with a fingle ftalk, refembling a young reed, and that this was compofed of feveral points, which, in the manner of cups, were inferred one into another; and that from thefe joints the leaves grew, and that they refcmbled thofe of the pine-tree. The branches are what this author calls leaves, and they do pret- ty well refemble the leaves of the pine-tree. They are long and flender, and of a bright green. Our great horfe- tail loves the heads of fprings in hilly countries, and is al- ways molt plentiful in fuch places.

GREOSEUNUM,- mountain -parfley, in botany, the name of a genus of plants of the umbelliferous kind, the characters of which are thefe: the flower is of the rofaceous kind, be- * ing compofed of feveral petals, arranged in a circular or- der on a cup, which afterwards becomes a fruit compofed of two large, oval, flattifh, ftriated, and marginated feeds, which fometimes depofit their covering. To this it may be added, that the leaves are like thofe of parfley, or hem- lock.

The fpecies of oreofelinum enumerated by Mr. Tournefort are thefe: 1. The great, parfley-leayed oreefeUnttm. 2. The lefTer, parfley -leaved oreofelinum. 3. The hemlock-leaved marfli oreofelinum. 4. The fhrubby, anife-leaved, African oreofelinum, which produces the galbanum of the (hops. This is called by many ferula galbamfera. Town. Inft. p. 319.

OREXIS, appetite. The appetite, when exceflive, or otherwife vitiated, is diftinguifhed by medical writers into feveral kinds, and defcribed under feveral names, according to its difference in degree, and other particulars. The firlt kind is the addephagia : this is the name friven that fpecies in which the food is not only eaten in too large a quantity, but is fwallowed in a particularly rave- nous manner.

The fecond is the orexis canina : in this cafe the patient it continually eagerly longing for food, and if it is not ready fo foon as he defires, he is fubjeft to fainting fits after the recovery, from which he does not feel the fame craving appetite.

The third is the pica, or fitta : this is the cafe when the patient has an eager appetite to things not fit for food, fuch as chalk, cinders, tobacco-pipes, and the like. The fourth is the malacia : this is diftinclively made thr name of that fpecies of exctjftve appetite in which the patf- i tient