MERCURY. 



779 



sulphurets, the black and the red, or the proto-sulphu- 

 ret and the deuto-sulphuret. The first is formed by 

 rubbing vigorously in a glass or porcelain mortar three 

 parts ot sulphur and one of mercury, or by adding mer- 

 cury at intervals, and with agitation, to its own weight 

 of melted sulphur. The second, which is commonly 

 called cinnabar, or vermilion, is formed by subliming 

 the proto-sulphuret. Large quantities of it are manu- 

 factured in Holland. The ordinary process consists in 

 grinding together 150 pounds of sulphur and 1080 of 

 quicksilver, and then heating the mixture in a cast- 

 iron pot, two and a half feet in diameter and one foot 

 deep, precautions being taken that the mixture does 

 not take fire. The calcined Ethiops is then ground 

 to powder, and introduced into pots capable of holding 

 twenty-four ounces of water each, to which are at- 

 tached subliming vessels, or bolt heads of earthen- 

 ware. The sublimation usually takes thirty-six hours, 

 when the sublimers are taken out of the furnace, 

 cooled, and broken. The acids sustain an important 

 relation to mercury. All of them either dissolve the 

 metal or unite with its oxides. Sulphuric acid exerts 

 little or no action upon it in the cold, but, if heat be 

 applied, it is decomposed, the mercury is oxidated, 

 sulphurous acid is disengaged, and the oxide com- 

 bines with the remaining acid. This proto-sulphate 

 of mercury crystalizes in slender prisms, forming a 

 mass, soft, and partly liquid. It is very acrid, deli- 

 quescent, and soluble in water. If it is urged with a 

 heat gradually raised until the mass becomes dry, 

 the metal is more highly oxidated, and a portion 

 of the acid is dissipated. On pouring boiling 

 water on this dry mass, it acquires a lively 

 yellow colour, forming an insoluble powder, known 

 by the appellation of turbith mineral, or yellow sul- 

 phate of mercury. The water, in this process, pro- 

 duces the usual effect which it has when it decomposes 

 metallic salts. Exerting a stronger attraction to the 

 acid than to the metallic oxide, it combines princi- 

 pally with the former, but, from the influence of 

 quantity on chemical affinity, the acid carries with it 

 a portion of the oxide, and conversely, from the 

 operation of the same force, the oxide which is pre- 

 cipitated retains a portion of the acid combined with 

 it. The neutral sulphate is thus resolved into a 

 super-sulphate, which the water dissolves, and a 

 sub-sulphate, which remains undissolved. This sub- 

 sulphate is chiefly used in preparing corrosive subli- 

 mate and calomel. Nitric acid acts on mercury with 

 facility, oxidating it, and combining with the oxide, 

 forming a perfect solution. The product of this- 

 action varies considerably, particularly with regard 

 to the state of oxidation, according to the circum- 

 stances under which it is exerted. If the acid is 

 diluted with rather more than an equal part of water, 

 and if the action is not accelerated by heat, the pro- 

 toxide only is formed, and the salt is the proto-nitrate 

 of mercury. If the acid is less diluted, and if its 

 action on the metal be promoted by heat, the perox- 

 ide is produced, and the compound is the per-nitrate 

 of mercury. Both these solutions, when concentrated 

 crystallize, a mass being -deposited, consisting of a 

 congeries of slender prisms. Both salts are corrosive, 

 deliquescent, and soluble in water. If the solution 

 of the per-nitrate is poured into water, a partial de- 

 composition happens, similar to that of sulphate of 

 mercury, and a yellow insoluble sub-per-nitrate of 

 mercury is precipitated. Nitrate of mercury is de- 

 composed by the alkalies and earths ; and in these 

 decompositions are well displayed the differences 

 which arise from different states of oxidation of the 

 metal By potash, soda, or lime, added to the 

 solution of the proto-nitrate, a precipitate of a gray- 

 ish colour, with a tinge of yellow, is thrown down : 

 from the solution of the per-nitrate the precipitate is 



yellow, more or less bright. These precipitates are 

 sub-nitrates, the oxide, separated by the alkali re- 

 taining a portion of the acid combined with it. The 

 action of ammonia on these solutions is more peculiar. 

 From the solution containing the mercury at a high 

 state of oxidation, it throws down a white precipitate, 

 which is a ternary combination of the oxide, with por- 

 tions of the acid and alkali. From the solution at 

 which the metal exists at the minimum of oxidation, 

 it throws down a precipitate of a dark gray or blue 

 colour. The gray precipitate by ammonia (oxidum 

 hydrargyri cincreum of the pharmacopoeias) is a 

 preparation much used in medicine. It is a mild 

 mercurial, and is very similar, in its operation on 

 the system, to the mercurial preparations formed by 

 trituration. To obtain it of uniform composition, it 

 is necessary to use every precaution to moderate the 

 action of the nitric acid on the metal, as by free 

 dilution with water, and by avoiding the application 

 of heat. A fulminating preparation of mercury is 

 obtained by dissolving 100 grains in one and a half 

 ounce by measure of nitric acid. This solution is 

 poured cold into two ounces by measure of alcohol 

 in a glass vessel, and heat is applied till efferves- 

 cence is excited, though it ordinarily comes on at 

 common temperatures. A white vapour undulates 

 on the surface, and a powder is gradually precipitated, 

 which is immediately to be collected on a filter, well 

 washed, and cautiously dried. This powder deton- 

 ates loudly by gentle heat or slight friction. It has 

 been very much used of late as the match powder, 

 or priming, for the percussion caps of the detonating 

 locks of fowling pieces. Two grains and a half of 

 it, mixed with one-sixth of that weight of gunpowder, 

 form the quantity for one percussion cap, according 

 to the researches of Aubert, Pelissier, and Gay- 

 Lussac. In preparing this powder in quantities, the 

 fulminating mercury should be moistened with thirty 

 per cent, of water, then triturated in a mortar, and 

 thereafter mingled with the sixth part of its weight 

 of gunpowder. Matches of this kind resist damp 

 very well, and take fire after several hours' immersion 

 in water. The detonating match, or priming pow- 

 der, made with chlorate of potash, sulphur, and 

 charcoal, has the inconvenience of rusting and soiling 

 the fowling pieces, and thence causing them to miss 

 fire ; whereas, with the above fulminating powder, 

 a hundred shots may be discharged successively. The 

 mercurial percussion caps are sold now in Paris for 

 three francs and a half per thousand. The acetic 

 and most other acids combine with the oxide of mer- 

 cury, and precipitate it from its solution in the nitric 

 acid. Muriatic acid does not act on mercury. When 

 mercury is heated in chlorine, it burns with a pale-red 

 flame, and the substance called corrosive sublimate 

 is formed. This deuto-chloride may also be formed 

 by mixing together equal parts of dry bi-deuto-sul- 

 phate of mercury and common salt, and subliming. 

 The corrosive sublimate rises, and incrusts the top of 

 the vessel, in the form of a beautiful white semitrans- 

 parent mass, composed of very small prismatic 

 needles. Its specific gravity is 5-14. Its taste is 

 acrid, stypto-metallic, and eminently disagreeable. 

 It is a deadly poison. Twenty parts of cold water 

 dissolve it, and less than one of boiling water. It is 

 composed of 73-53 mercury and 26'47 chlorine. It 

 may be recognised by the following characters : It 

 volatilizes in white fumes, which seem to tarnish a 

 bright copper-plate, but really communicate a coat- 

 ing of metallic mercury, which appears glossy white 

 on friction. When caustic potash is made to act on 

 it with heat in a glass tube, a red colour appears, 

 which by gentle ignition vanishes, and metallic mer- 

 cury is then found to line the upper part of the tube 

 in minute globules. Solution of corrosive sublimate 



