Cinnabaris Nativa. Minium Grae-corum. Native cinnabar: a ponderous, red, fulphureous ore of mercury; found in Spain, Hungary, and several other parts of the world. The finest is imported from the East Indies: partly in pretty large irregular masses; partly in smaller roundish ones, smooth without, and striated within; both externally and internally of an elegant deep red colour, which is greatly improved by grinding the mass into fine powder.

Cinnabar consists of quicksilver and common brimstone; in the proportion of not less than four(a), commonly six or seven (b) parts of the mercury, to one of the sulphur: the finer its colour, the more mercury and the less sulphur it is found to hold. The native cinnabar generally contains also a quantity of earthy matter, from which it may be purified by sublima-tion. If this earth should be of the calcareous kind, or if calcareous earths, iron filings, or other substances that absorb sulphur more strongly than mercury does, be added; more or less of the sulphur, proportionably to the quantity of such absorbent addition, will be detained at the bottom of the subliming vessel: on this principle, the coarser cinnabars may be freed from their redundant sulphur as well as from their earthy matter, and thus rendered of a high colour: or the whole of the sulphur may be detained, by an increase of the absorbent material, and the pure mercury dislilled off in its running form: one part of lime or iron filings is generally sufficient for extricating all the mercury from four parts of cinnabar. The humid menstrua, that dissolve either one or the other of the ingredients of cinnabar by them-selves, have little effect upon the compound; the mercury being protected by the sulphur from the action of acids, and the sulphur by the mercury from that of alkaline liquors: alkalies indeed, even in the dry way of sublimation, do not so perfectly detain the sulphur as bodies of the earthy or metallic kind.

(a) Lemery, Ceurs de chimie, part. i. chap. viii. operat. 2.

(b) Cramer, Elem. artis docimasticae, torn. i. edit. ii. p. 387. Malouin, Chimie medicinale, part. iv. chap. 38.

Native cinnabar has by many been preferred, as a medicine, to that which is made by art, but apparently on no good foundation. The only difference between them consists in this; that the native is subject to an admixture of heterogeneous matters, which are not perhaps always innocent (a); and that the proportions of its constituent ingredients are more precarious than in the factitious. The native cinnabar is therefore deservedly rejected by the London and Edinburgh colleges.