MER

M E R

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Before the blowpipe it is almoft entirelyvolatilizable with a blue flame, and a fulphu-reous odour.

Cinnabar occurs in two diftintl rock-forma-tions. It is found moft abundantly in theindependent coal-formation : alfo in beds inter-pofed between primitive argillaceous fchiftus.and chlorite flate, accompanied by quartz, cal-careous fpar, fpathofe iron, micaceous iron, andiron and copper pyrites.

The mofl; abundant European mines of Cin-nabar are at Idria in Carniola, and Almaden inSpain , in the independent coal-formation. Itoccurs more fparingly in primitive llrata atMorsfeld in the Palatinate , Mofchellandfbergin the territory of Deux Ponts; alfo in Saxony ,Bohemia, Hungary , and Tranfylvania. It is metwith in Japan, Kamtfchatka, and Siberia inAlia, and near Guanca Velica in Peru .

2. Subjp. Fibrous cinnabar. Hochrother , Z.Wern.

Its colour is bright fcarlet, palling to crimfonand Aurora-red. It occurs in mafs and difle-minated. Internally it is glimmering with afilky lultre, but its crofs fradture is dull. Itgfradfture in one direction is fine-grained earthy,in the other is minutely fibrous. Its fragmentsare indeterminately angular, blunt-edged ; it iscpake; acquires a flight polilh by fri&ion, andwhen pulverized is of a fcarlet-red. It ftainsthe fingers in a fmall degree; is very foft, pallingto friable; may be cut with a knife; and is ofgreat fpecific gravity.

It is a rare mineral, and is always accompa-nied by the preceding fubfpecies : it is princi-pally found in the Palatinate.

3. Sub/p. Hepatic Cinnabar. Cinnalre alca-lin, Born.

Its colour is bright-red ; it occurs in mafs ;its frafture is foliated; its fragments are rhom-boidal; it is tranfparent. By fri&ion it exhalesa very ftrong odour of fulphuretted hydrogen.It occurs in white calcareous fpar at Idria inGarniola.

Sp. 6. Horn Mercury. Queclflber Hornerx,Wern. Mine de mercure cor nee, Broch.

Its colour is alh-grey, palling into yellowifh-grey, greyifti-white, and greenilh-grey; whenpenetrated as it fometimes is with native mer-cury it is blackifh-grey. It occurs very rarelyin mafs, moll frequently in fmall and thin tu-bercular crufts, the cavities of which are linedwith minute cryftals, alfo in fmall globulesformed by the aggregation of cryftals. Theonly well afcertained form of its cryftals is adodecahedron compofed of a four-fided prifm

terminated by tetrahedral pyramids: the planesof the prifm are hexagons, thofe of the fummitsare rhombs. The cryftals are generally veryfmall and fplendent. Internally they are fplen-dent with a diamond luftre, palling fometimesto metallic. The fracture as far as it can beobferved is ftrait lamellar. It fometimes pre-fen ts fine-grained diftindt concretions. It isfaintly tranllucent; foft; may be cut with aknife, and is eafily frangible.

On expofure to the blowpipe it is totallyvolatilized without decompofition. It is folublein water, and the folution gives an orange-coloured precipitate with lime-water. Theonly analyfis of this mineral that we poflefs isan imperfect one by M. Woulfe, the difcovererof it, from which it may be concluded, withconfiderable probability, that it confifts whenpure of about

64 Sulphat of mercury36 Muriat of mercury

100

It occurs in the quickfilver mines of thePalatinate, and Deux Ponts ; at Idria, Horfo-witz in Bohemia, and Spain .

2. Analyfis and Affay.

There are no very exaft analyfes of any ofthe mercurial ores, but the following methodsof examining them feem to be liable to little orno objection.

The native mercury and native amalgam maybe thus analyfed. Let the ore be digefted inmoderately ftrong nitric acid, which will takeup the mercury, and filver, and bifmuth, ifthere fhould chance to be any prefent: a minutequantity of gold may alfo be contained in theargentiferous mercury, which will be left un-touched at the bottom of the folution, in theform of a brown powder. The nitrous folutionbeing concentrated by gentle evaporation, tillit is on the point of cryftallizing, is to be pouredinto a large quantity of pure water, by whichthe bifmuth will for the moft part be feparated.Having thus got rid of the bilmuth, add to thefiltered liquor a folution of common fait or anyother neutral muriat, by which both the filverand mercury will be thrown down in the ftateof muriat. This being feparated, drop into theclear liquor fome carbonated alkali as long a$any precipitate takes place, then boil the liquor,and feparate the precipitate by filtration. Themuriatic precipitate is now to be digefted mmoderately dilute nitre-muriatic acid, which