c o c

COE

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To to a 14 gallon boiler of well tinned copper,pot ten gallons of diftilled or very clear riveror rain water (fpring-water will not anfwer thepurpofe). When the water boils fprinkle in bydegrees a pound of fine cochineal previouflyground in a clean done mortar to a moderatelyfine powder : keep up a moderate ebullition forabout half an hour, and then add three ouncesand half of cryftallized carbonat of foda : in aminute or two afterwards draw the fire, andthen add to the liquor an ounce and a half ofRoman alum very finely pulverized; ftir themafs with a clean (tick till the alum is difl'olved,then leave it to fettle for 25 minutes: draw offthe clear liquor with a glafs fyphon, and fepa-rate the fediihent from the refidue by {trainingit through a clofe linen cloth. Replace the clearliquor in the boiler and ftir in the whites of twoeggs previoufly well beaten with a quart ofwarm water; then light the fire again and heatthe liquor till it begins to boil, at which timethe albumen of the eggs will coagulate andcombine with the earth of the alum and thefined part of the colouring matter: this fedi-ment is the carmine, and being feparated byfiltration, and well wafhed on the filter withdiftilled water, is to be fpread very thin on anearthen plate and flowly dried in a ftove: afterwhich it is ready for ufe. The fineft part ofthe colouring matter of the cochineal being thusfeparated, the refidue may be employed in thepreparation of red lake in the following manner.Add two pounds of pearlafh to the red liquorfrom which the carmine was precipitated, andreturn it into the boiler together with the dregsof the cochineal, and boil the whole gently forabout half an hour; then draw the fire, andafter the fediment has fubfided drain off all theclear liquor into clean wooden or earthenwareveffels (the latter however are the belt, as thealkaline folution is apt to difi'olve a little extrac-tive matter from the wood). Then pour uponthe fediment a fecond alkaline ley prepared bydiffolving a pound of pearlafh in two gallonsof water, and boil this alfo upon the dregs forhalf an hour, by which procefs the whole of thecolouring matter will be exhaufted. Separateby filtration the liquor from the dregs, and re-turn both the alkaline folutions into the copper.When this bath is as hot as the hand can bear,add by degrees three pounds of finely pulverizedRoman alum, obferving not to add a fecondportion till the effervefcence from the firft hasentirely fubfided. When the whole of the alumhas been put in, raife the fire till the liquor fim-

• Anslyt. S

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mers, and continue it at this temperature forabout five minutes, at which time if a little istaken out and put into a wine glafs, it will befound to confift of a coloured fediment diffufedthrough a clear liquor. After {landing quieta while the greater part of the clear fupernatantliquor may be poured off, and the refidue beingplaced on the filter, will there depofit the co-loured lake, which after being accurately walkedwith clean rain water, may be covered with acloth and allowed to remain for a few days tillit is half dry: it is now to be feparated fronvthe filter, to be made up in fmall lumps and'placed in a ftove to dry. By this managementa pound of good Mexican cochineal will affordone ounce and a half of carmine, and about apound and a quarter of red lake.

If the colour is required to incline fomewhattowards fcarlet, this may be effected by grind-ing along with the cochineal from a quarter tohalf an ounce of the bell annotta.

For the ufe of cochineal in Dying, fee thatarticle. ■

COELESTINE. Celejlin, Warner. Stron-tiane Sulphatee , Hauy.

The native fulphat of ftrontian, called coelef-tine, from the bluifh tint which it generallyaffumes, is divided into three varieties, thefibrous, foliated, and compact.

1. Fibrous coeleftine. Fajriger celejlin.

Its colour is between indigo-blue and bluilh-grey, palling fometimes into milk-white, bykeeping it becomes white or colourlefs. It oc-curs in mafs, in plates and cryftallized. Itslongitudinal fradlure prefents a Ihining luftre,its crofs fradiure is gliftening and pearly. Itslongitudinal fraCture is curved-fibrous, ap-proaching to foliated; its crofs fradture islplintery. It is tranllucent; fomewhat fofterthan fluor; eafily frangible : fp. gr. = 3-83.

According to the analyfis of Klaproth 1 itContains 58 Strontian

42 Sulphuric acid,

- with a trace of iron

100

It occurs in ferruginous marl in the vicinityof Briftol, and at Frankftown in Pennfylvania.

2. Foliated Coeleftine. Blattriger celejlin.

Its colour is milk-white, palling into blue: itoccurs in mafs, or cryftallized.

1. In ftrait prifms, with rhomboidal bales(which is its primitive form) the angles ofwhich are 104°—48' and 75 0 — tl'.

2. In cuneiform octahedrons.

[, 1 . p. 394.

VOL. I.

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