Page:Cyclopaedia, Chambers - Supplement, Volume 1.djvu/542

 COL

COL

ture of the reft of the forts of that kind. Mem. AcaJ. Par. 1701.

The kernels, or feeds, of this fruit, Which are carefully thrown away by the apothecary, according to the direction of the dif- nenfatory writers, when treated in the fame mannc, yield much tire fame principles with the pulp, except that the lalt running liquor contains much lefs volatile fait than that of the pulp, as is not only fcnfible by its want of fmell, but by its fermenting very (lightly with acids, whereas that from'the pulp ferments very (trongly. As thefe fort of analyfes give, how- ever, but little light into the nature of bodies, Mr. Boulduc tried many other experiments upon it; he fermented it with muiT, or new wine, and then diftilling it in a balneum mariae, he obtained a very penetrating fpirit, which pofiefled all the bitternefs of the coloc } nth, and made an extract from the refi- duum. The bitter fpirit proved a purge, but operated roughly, occafioning griping? and naufeas.

'J 'he quantities ufed in this prccefs were four ounces of colo- cynth, and fix pints of mud, and from the remainder of the difiillation well clarify'd, there was made two ounces of an ex- tract ; the quantity proving plainly that a large portion of the eilent'ial ("alts of the wine remained with the matter of the co- kcyntb This extract is the fafeft and beft of all the prepa- rations of coUepttft'i it purges gently, and without irritation, in a dofe often or twelve grains.

Colocynth., itifufed in rain water, yields only an mfipid phlegm by difUNation, but the remainder yields a very fine extract of a tolerably mild purgative virtue ; a pound of the pulp of colo- cyntb thus yields two ounces and an half of extract, and the remaining mafs of the colocynth does not appear to contain any refin. It is ufual to attribute the violence of all purgative me- dicines to their abounding in refinous parts. To try whether this was the cafe in this fimplc, Mr. Boulduc finifhed his ex- periments on it by making an e> tract from it, by means of fpirit of wine. Eight ounces of the clean pulp yielded only half an ounce of a refinous extract, and the refiduum yie'ded two ounces of a coarfe extract, by means of water, but this was of a bad confidence, and would fcarcc hang together. Mem. Acad. loc. cit.

Either of thefe extracts, given alone, proved troublefome me- dicines : and all that appeared from this, and from the whole, was, that in order to have the virtues of this fruit in a gentle, and fafe manner, its faline and refinous parts mull be left to- gether, and only feparated from its terreiiria! and mucilaginous ones, by means of long fermentation with mult or water, be- fore its being evaporated into an extract ; for that all its vio- lent effects are owing to thefe terreltrial and mucilaginous particles. Sec Colochjintida, Cyd.

COLOGN earth, a fubftance ufed in painting, much approach- ing to amber in its itructure, and of a deep brown. It has generally been cfleemcd a genuine earth, but lias been difco- vered to contain a great deal of vegetable matter, and indeed, is a very Angular fubftance.

It never conftitutes an entire flratum in the earth, but is lodged among other ftrata in large flat detached moffes. It is mode- rately dry, while in the earth, and of a foft crumbly texture. When dried, it is of a deep,dufky brown, of a very clofe, com- pact, and fine ftructure, and very remarkably light; it is of a fmooth, even furface, dry, but not harm to the touch, crumbles eafily to pieces between the fingers, and (lightly ftains the hands ; it adheres firmly to the tongue, and is of a very auftere and afiringent ta!t«, but not at all refembling the aftrin- gency of the boles, or any thing elfe < f the mineral kingdom, but plainly refembling the taite of oak bark It makes no ef- fervefcencc with acids; if thrown into water, it fwims on the furface, till thoroughly wetted ; and if brought into contact with burning coals, it takes fire, and burns of itfelf, till re- duced to yellowifh afhes.

It is eafy to difcern from this account, that though this is ge- nerally efteemed an earth, and known to the world by no other name, it is no pure native foffile, but contains more vegetable, than mineral matter, and owes its origin to there- mains of wood which has been long buried in the earth. It is dug in Germany and France : the quantities confumed in painting, in London, are brought from Cologne, where it is found very plentifully ; but our own kingdom is not without it, it being found near Birmingham, and on Mendip hills in Some rfetfli ire ; but what has been yet found there is not lb pure or fine, as that imported from Cologn. Hill's Hift.ofFoffils, p. 64.

COLONEL {Cyd.) — Formerly, inftcad of colonel, the French ufed the word coronet ; and this old fpelling comes nearer to our common way of pronouncing the word colonel.

COLONUS, an hufbandman, or villager, who was bound to pay yearly a certain tribute, or at certain times of the year, to plough fome part of the lord's land ; and from hence comes the word clown, who is called by the Dutch boor, Blount.

COLOR, in the antientmufic. See Colours.

Coxor conchitiacm. See Conchil[acus«/«-.

Color hidi.us. See Ikdicus color.

COLORATURA, in the Italian mufic, is ufed to denote all forts of variations, trillos, diminutions, &c. that can render a fong agreeable. Brojf. Diet. Muf. in voc. See Trjllo, Diminution, &c.

COLOURS {Cyd) — The greateft perfection in the art of co- lours, would be to find the means of preparing the fineft co- lours, without the ufe either of acid or alkaline falts, which ufually fubjedt the colours to change, or e fe are apt to prey upon the cloch, canvas, &c. as we fee in verdigreafe, the blue and green chryftals of copper, &c- It appears highly probable, that the Indians, for making the fine bright and durable co- lours, wherewith their chinces and callicoesare (ruined, make ufe of metalline folutions ; for fome ftained callicoes, brought from thence, having been kept for forty or fifty years, the bright colours have been obferved to cat out the cloth, exactly in the fame manner as acid fptrits, which diilblve metals, are found to do. SbavJs Lectures, p. i86»

Since thefe, then, are the inconveniences attending fuch co- lours, we ought to fearch for menilruums with which to ex- trait cJcurs, which are neither acid, nor alkaline ; and for fucb metalline calxes, precipitates, or powders, as will not lufe their colours, by bting well warned to get out their falts : to prepare certain metalline matters by mere calcination, or the bare afliftance of ilze ; and lallly, to look out for native cdours, wherein no faline matter abounds. Mr. Geoff roy has given a very curious procefs for the making two clear, fpirituous, inflammable liquors, which differ very little in tafte and fmell, and being mixt together give a fine carnation colour, without any fehiible fermentation. To make the firft of thefe liquors, put a final! handful! of dried red rofes into a glafs bottle, pour on them rectified fpirit of wine, till it covers them an inch ; let this (band in a cold in- fufion four or five hours; then pour off the liquor, which will be clear and colourlefs, as when put on. The fecond liquor is made by dropping into rectified fpirit of wine fo much oil of fulphur, by the bell, or fpirit of vitriol, as will be borne in it without giving it any very fenfible acidity when tailed. V\ hen thefe liquors are thus prepared, let a finall quantity of the latter be dropped into fome of the former, and the whole will become of a fine carnation colour, though there is no fermentation, nor any other change perceived in it, but barely that of colour.- If, inftead of this laft liquor, there be added to the firit a few drops of the fpirit of fal armoniac, the whole will become green.

Make a flight infuflon of galls in water, fo as not to colour 4 the water; nuke alfo a weak folution of green vitriol in water, fo that it may appear colourlefs; mix thefe two co- lourlefs liquors together, and an inky blacknefs is immedi- ately produced ; add to this black liquor a little oil of vU triol, and the liquor becomes pellucid and colourlefs again ; then add to this a little fait of tartar, and the whole is black again.

Put a little bruifed camphor into rectified clear oil of vi- triol; make the mixture, and it will become black, and the camphor will be diflblved ; add to this a little water, and the liquor becomes clear, and the camphor is found fepa- rated at top, in its own form, and native whitenefs. Infufe lignum nephriticum in cold water, and pour off th* clear liquor. This held up againft the light, appears of a fine yellow, but viewed from the light, of a beautiful bluej a little fpirit of nitre put to this liquor, makes it lofc the power of reflecting the blue rays, and a little oil of tartar, afterwards added, recovers that power again. Logwood, infufed in water, gives a red colour. Put to this a little fpirit of urine, and it becomes of a fine purple; and drop in afterwards a little fpirit of fait, and it becomes of a pale red.

A beautiful blue tincture may be made from filings of cop- per, by digefting them in fpirit of urine, hartfhorn, or the like. The addition of oil of vitriol deftroys the blue coLur ; and a little fpirit of fait turns it green.

Pellucid oil of vitriol, mixed with pellucid oil of turpentine, produces a thick red balfam. And common oil, mixed with fair water, by means of a little wax, and continued rub- bing turns into a thick white balfam, called cold cream. Oil of vitriol, diftilled from quickfilver, leaves a wh te powder behind, which, if water be poured on it, becomes yellow,

DilTolve quickfilver in fpirit of nitre, and to part of it add fpirit of urine, and a white powder is precipitated ; to an- other part of the folution add oil of tartar, and a yellow powder falls to the bottom.

Dip a new pen in fpirit of vitriol, and write with it on common blue paper, and the letters will appear red. A pellucid folution of faccharum Saturni being written with on paper, becomes invifible, when dried ; but the bare fumes of an infufion of quick lime, and orpiment, in wa- ter, will render the invifible writing black and legible. Volatile fait of fal Armoniac, which is white, mixed with cry- stals of copper, which are green, produce a fine purple. fifty's Lectures, p. 173 — 176.

The original and fimple, as well as the mixt, «7«r$are producible by mixture. Thus, if the fun's rays pafs through two pieces of glafs, the one blue, and the other yellow, and be afterwards received upon a white paper,the col.ur there feen, is green. The dyers make cloth blue wkh woad, and- then turn it green by the yellow herb called luteela, or dyer's

weed.