Hydrargyri Sulphuretum Cum Sul-Phure. Lond. Sulphuret of Mercury with Sulphur

"Take of mercury, sulphur, each a pound. Triturate them together until the globules disappear."

Sulphuretum Hydrargyri Nigrum, Edin. Black Sulphuret of Mercury.

"Take of purified mercury, sublimed sulphur, of each equal weights. Rub them together in a glass mortar with a glass pestle, until the globules of mercury altogether disappear. It may also be made with double the quantity of mercury."

Hydrargyri Sulphuretum Nigrum, Dub. Black Sulphuret of Mercury.

"Take of purified mercury, of sublimed sulphur, each one part. Rub them together in an earthen mortar until the globules disappear."

Syn. Sulphure de Mercure noir (F.), Schwarzes Schwefelquecksilber (G.), Solfwio di Mercurio nero (I.).

During the trituration of the mercury with the sulphur, Fourcroy supposed that the metal is imperfectly oxidized by attracting oxygen from the atmosphere; but this opinion has been disproved by the experiments of Proust2; and a chymical combination is effected between the mercury and the sulphur. Mr. Brande1 regards it as a compound of 58 parts of bisulphuret of mercury and 42 of sulphur, and this opinion accords with that of Mr. Phillips.2

1 Hydrargyrus e sulphure, P. L. 1787. Hvdrargyri sulphuretum nigrum, P. L. 1824.

2 Journal de Physique, liii. 92.

Qualities.- Black sulphuret of mercury is in the form of a very black, impalpable, inodorous, insipid powder. When heated in an open vessel it emits sulphurous acid gas; becomes first of a deep violet hue, and afterwards sublimes of a brilliant red colour; being converted into the bisulphuret and mercury. It is often ill prepared, which may be known by rubbing a portion of it on gold; to which, if it be good, no whiteness will be communicated. It is, also, sometimes adulterated with ivory black, which may be detected in it by throwing a little of the suspected sulphuret on a red-hot iron : if ivory black be present, some ashes will be left after the volatization : but the pure sulphuret is completely dissipated. It consists of 1 eq. of mercury = 202 + 1 of sulphur = 16.1, making the equivalent=218.1 (Hg S.)

Medical properties and uses. - This mercurial preparation is mildly alterative. It is chiefly employed against scrofulous swellings, and in cutaneous affections. But it is on the whole a very uncertain preparation, and requires to be long used to produce any sensible effects. The dose is from grs. v. to 3ss., given twice or three times a day.

Hydrargyri Bisulphuretum. Lond. Red Sulphuret of Mercury

"Take of mercury, two pounds; sulphur, Jive ounces. Having melted the sulphur over the fire, mix in the mercury, and, immediately the mass swells, remove the vessel from the fire, and cover it strongly to prevent it from catching fire; then rub to powder and sublime."

Hydrargyri Sulphuretum rubrum, Dub. Red Sulphuret of Mercury.

" Take of purified mercury, nineteen parts; sublimed sulphur, three parts. Mix the mercury with the melted sulphur; and if the mixture take fire extinguish it by covering the vessel; then rub the mass to powder, and sublime it."

Syn. Sulphure de Mcrcure rouge (F.), Zinnober (G.), Solfuro di Mercurio rosso (I.), Cinabrio (S.), Shengerf (H.).

By these processes the mercury and sulphur are more intimately combined, and a bisulphuret is produced. The inflammation which is apt to happen after the mixture of the mercury with the melted sulphur, when the mass swells and explodes, as frequently occurs, is similar to the combustion during the union of sulphur by heat with some other metals, independent of the presence of air; hence, covering the vessel, without removing it from the fire, does not check the combustion, although, by excluding the air, a real inflammation of the materials is prevented. In the second part of the process great caution is necessary to prevent the neck of the vessel in which it is sublimed from being choked up by the sublimed sulphuret; as by the occurrence of such an accident the vessel would be burst by the confined vapours. To avoid this, a wide-necked vessel should be used.

1 Manual of Pharmacy, p. 303.

2 Trans, of Pharm. 1837. p. 245.

3 Cinnabaris factitia, P. L. 1754. Hydrargyriasulphuretus ruber, P.L.1787, Hydrargyri sulphuretum rubrum, P. L. 1824.

The cinnabar of commerce, which is chiefly used as a pigment, is manufactured in Holland on a very extensive scale1; and the following method has been proposed by Mr. Kirchoff, for obtaining it in the humid way. First, form ethiops mineral, by triturating, in a porcelain cup, with a glass pestle, 300 grains of mercury, and 68 of sulphur, moistened with a few drops of solution of potassa, and then add to it 160 grains of potassa, dissolved in an equal weight of water. Heat the vessel with the ingredients over the flame of a candle continuing the trituration, and adding, as the fluid evaporates, pure water from time to time, so as to keep the ingredients covered to the depth of an inch. At the end of two hours, if the trituration have been continued, the colour of the mixture changes from black to brown, and then to red; after which no more water should be added, but the trituration must be uninterruptedly continued until the mass have acquired the consistence of a jelly, and the red colour attained considerable brightness and beauty; the heat must be then immediately withdrawn, otherwise the red soon changes to a dirty brown.2

Qualities. - Red or bisulphuret of mercury, factitious cinnabar, is a powder of a very bright red colour, which is inodorous, insipid, and insoluble in water, alcohol, and the majority of acids. It is decomposed, however, by nitro-hydrochloric acid, which combines with the mercury, and disengages the sulphur: but it is not altered by solutions of the alkalies, even when boiled with them; although lime, potassa, soda, and most of the metals, decompose it when distilled with it. According to Proust, 100 parts of this sulphuret consist of 85 of mercury, and 15 of sulphur; but according to the later experiments of Guibert3, the proportions are 86.1803 of mercury, and 13.8197 of sulphur: Mr. Phillips states them at 13.6 of sulphur+ 86.4 of mercury. In equivalents, it consists of 1 eq. of mercury = 202+ 2 of sulphur = 32.2=234.2 (Hg S2). This preparation is sometimes adulterated with red lead, dragon's blood, and chalk; the first is discovered by the same process as was described for discovering it in the red oxide; spirit of wine detects the second by extracting the colouring matter; and the last is discovered by an effervescence being excited by hydrochloric acid; and the production of sulphate of lime on adding sulphuric acid.

1 See a description of the method, Annales de Chimie, li. 196.

2 Nicholson's Journal, 4to. ii. 1.

3 Journ. de Pharmacie, Aout, 1816, p. 374.

Medical properties and uses. - Bisulphuret of mercury is alterative and deobstruent. It was formerly much used in cutaneous diseases, gouty and rheumatic affections, and in worms. It is now, however, scarcely ever prescribed. It has been recommended for fumigations in syphilis; but, on account of the sulphurous vapours, it is less fit for this purpose than the grey oxide. The dose for internal use is from grs. x. to 3ss. made into an electuary or bolus.