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Hydrargyrus calcinatus, P. L. II8 . Mercurius calcinatus, P. L. 1z45.
This preparation Was sirst introduced into the Pharmaco poeta of 1745. There is veru litile disserence belween ii and the nitric oxyd, is the lalter be Weli prepared; eXcepi, per-baps, that in this there is some hat more Oxygen ; Lavolsier SayS, OXygen .l0, mercUry . 90. But as the composition ofiliis oxyd is matter of more certainty, as it can contain nonitric acid, and as it is given internalty by many practitioners; as too, according to the modern mode of iis preparation, and the employment of the necessary sire for other purposes atthe fame time, it is not an expensive article, it has been thought right to retain it; and the ternas used to eXpress eaeliare sufficiently indicative of their differetice of preparation to
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prevent confusion. A thin stratum os mercury is introducedinto a mattrass, With a broad fiat bottom, and long narro necla, dra n out to a capillary opening ; this prevenis theescape of the mercury, and allows a stoW admission of air, theoxygen of Whicli, at the degree of heat applied, graduallyunites with the metat, sirst into blackisti scales, and at last forming a mass of a someWhat deeper red colour than thenitric oxyd, whicli is to be reduced to a sine powder. The vhole process may probably require an eXpoSure of siX Weelas.
Ηydrargyrus muriatus, P. L. II 8I. Mercurius corrosivus sublimatus, P. L. 1715. P. L. 1I2O.
Boii the mercury with the sulphuric acidin a gla88 Vesset, untii the sulphate of mer-cury is test dry. Rub this, When it is colit, With the muria te of soda in an eurthen War mortar: then sublime it in a glass cucurbit in creasing the heat gradu ally.
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This sali is directed according to the process which was introduced into the last Pharmacopoeia, and whicli originaled with Boulduc, in l730. An infinity of other methods have been employed, but none is more Simple, Convenient, or uniform than this. The frst division of the process forna a sulphate os mercury, a portion of the sulphuriCacid yielding iis oXygen to the metat in a botling temperature, and passing over in the form os sulphureous acid gas. The
metal thus OXydiged unites to the remaining sulphuric acid, and a White sulphate remains. On account of the gas Whicharises, this sit Ouid be performed with sonae caution on the part of the operator. In the second division, the sulphate of mercury is mixed intimat ely mith dry muriate of soda, andon expostare to heat a doubie decomposition talaes place, and the oXymuriate os mercury sublimes. It fornas a dead white, shining, spicular masS, eastly powdered, not altered by eX- postare to air, and it has a bighly acrid, caustic, metallic laste. It is one of the most violent pol sons Enown. One part is solubie in 20 of water at the ordinary temperature, and in eat 212': IOO paris of boiling aikohol dissolve 88, and at60' about 25. Is the fixed ali alios be added to a solution osit, an orange-coloured precipitate forms, which soon changesto a bricla red. It is solubie in acids Without de composition. and partly decomposed by expostare to light, Which should there re be avoided in the shops; and it is also decomposed by liquid preparations os cinctiona and of many other Vegetableg,
sisis of II, 6 oxygen , 82,4 metal, and the sali, dividen into iis three component paris, of 69,I metal, I2,3 oxygen, I 8 acid. This relation is of much consequence in comparing it withanother compound of the sanae elemenis, but the mercury in
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to these two compounds, which might sussciently distinguisti belween them, and express their relations, and at the fame time a void the unscientific term Calomes, which had been adcipi ed sor one of them in the former Pharmacopoeia. Theterm Oxymuriate has mostly been used to express combina tions of oxymuriatic acid; but here the acid is certainly in thestate os common muriatic acid, and the larger proportion ofoxygen it contains is combined with the metat: stili as such greater relative proportion of OXygen does actualty exist, theyhave considered themselves justified in this use of the tem, rather than have recourse to qualities, which are avoided in ali other instances for the distinction : they have, theresere, discontinued the name of Misarnrus eorrodens muriatacus adopted in the first specimen, and notwithstanding more recent experiments they have not thought it no proper toalter the terms whicli are Dund to convey a sussicient sp ei sic distinction.
Calomelas. 'harnrus muriatus mitis, P. L. 1787. Mercurius dulcis sublimatus, P. L. II45. Calomelas, si quater aut pluries sublimatur mercurius dulcis sublimatus, P. L. II20.
Rub them together untii the metallic globules di sappear; then sublime, takeout
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the sublimed mass, and reduce it to poWder, and sublime it in the Same mann eri Wi Ce more successively. Lastly, bring itinio the state of very sine poWder, by the Sume Proces s whicli lias been directed sor thol reparation of challi.
This preparation os mercury is' in most eXtensive use, and there re requires espectat attention. Four Paris of OXymuriate are trituraled with three of mercury untii the globules of the lalter disappear, and as in this operation the lighter particles of the acrid sali are driven abolit, the operatorshould cover his molith and nostrils while he is performingit. Some have advised the addition os a litile water or spirit to preverat this effeci; and there can, in practice, be nO Objection to the use of either. . For the sublimation of the compotind a greater heat is required than for that of the oxy- muriate alone. It forms in the subi ming Vesseis a compaci, hard, shining, striated cake. Is the union be not complete, Some Oxymuriate Will sirst arise and will be seen to forna thesirst deposition; or ori the other hand, a litile metallic mer-cUry may sublime in the fame Way; either extreme is to be
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to Beaume, there is no intermediate state betweon the tWΟ pre parations, and is too large a proportion either of oxymuriateor mercury be used it will sublime unaltered. The presentProportions are taken as the best, froin the result of very extensive practice, though it may seem Do m Mr. Chenevix's analysis, that more mercury is directed than is actualty necessary ; for, according to him, 54 paris of metat are sussicient for 1OO of oxymuriate; 75 is the proportion here USed. According to the received nomenclature os sub-salis, this ought rather to be considered as a muriate os mercury; itdoes not differ from ille Oxymuriate meret y in the lesser Proportion os iis acid, for the addition os more acid does notconvert it into the oxymuriate, but the difference lies in therelative degre e of oxidation of the base; and Dpon the whole, it has been thought practicatly unsala to adopi a term nearly allied to bbarnrus muriatus, whicli has here tofore been generalty used sor the acrid oxymuriate, and much better toadopi a definite nam e for each, which, With common attention, can Scarcely be con unded together in prescription, than to take ei ther a long and circuitous mode of eXpression, or a name whicli might be attended with rish. A very elegant and useful modification of this process has lately been adopted by Mr. Howard, chemist, who sublimes the submuriate into Cater, mitti the vapour of whicli it mixes as ita rises in iis gasseous forin, and subsides at orice as a fine impalpable precipitate to the bottona of the water. Formerly Preparations of mercury analogous to this were distinguished according to the number of sublimations they had under-gone. Aster three sublimations it Was Mercurius dulcis, after fix Calomelas, and after eight Panacea mercurialis: butaccording to Beau me, a smali portiori of oxymuriate is form-ed by each of these repeat ed sublimations, probably frona theabsorption os oxygen by the heated preparation Dom the atrof the vesseis, and heiace no advantage, but rather the CORU
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IIYDRARGYRI SULPHURETUM NIGRUM.
νγdrarnrus cum Sulphure, P. L. II 87.
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Hydrargyrus sulphuratus ruber, P. L. 1787. Cinnabaris factitia, P. L. 1745.
Sublimed Sulphur, eight ΟUnCOS. Having mel ted the sulphur over the sire, mix in the mercury, and HS SO On RS the muSShegins to Saveli, remove the vesset from thesire, and Couer it With considerable sorce, to prevent inflammation ; then rub the massinio poWder, and sublime.
The immediate union of the metal and sulphur are here facilitate I, in the sirst instance, by heat, for the mercury is added to the sulphur previousty fused, and the sulphuret is afterWards sublimed. The difference of colour, form, and relation to Other Substances, demonstrate that these two combinations of the fame ingredients, the Hydrargyri Sulphuretum nigrum and rubrum, differ Dom each other, butthe circumstances iapon whicli this difference depends have been Variousty eXplained. Fourcroy states that it arises Doma greater proportion os oxygen being combined with the mesal
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in the last than in the sirst, assuming that each is in facta sulphuret of Ovd of mercury. But more lately Ρroust Iurn. de P s. 53.) has sald, that each is merely a sulphuretos mercury, and differs hom the other in the proportion offulphur, and also, that the sublimed sulphuret consists of mercUry .85, sialphur . 15. Aster the admixture of the two substances in the sirst part of the process, the mass heais,sWelis, and explodes With considerable force, and is it be thenexposed to the air it Will inflame. The commencement there re of this effect is to be caresully Walched, and a coverimmediately put Upon the vesset, and pressed upon by a great Weight proportionale to the quantity. Caution is necessaryasterWards that the neck of the vesset Dom Whicli it is sublimed is not so smali as to be stopped up by the condensationos the sublimed sulphuret, Whicli Will very probably happenis a common retort be used. The red sulphuret, thias prepared, forms a deep red calae, With a Shining Striated appearance, and, When reduced to poWder, assumes that rich red colour Whicli characterises Vermilion, under Whicli nam e it is Enown in the aris. It is tasteless, not altered by air, insolubie in water or aikohol, sublimes unchanged in close vesseis, and burns in the open air With a blue flame. The mercury may
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Hydrargyrus cum creta, P. L. II87. Μercurius aikaligatus, P. L. 1 45.