MER

M E R

( 87 )

beft, we fhall here defcribe their method ofproceeding, as related by M. Tuckert. u Thismanufacture confifts of two diftinCt operations,the one being the preparation of the ethiops, theother the converfion of the ethiops into cin-nabar. To make the ethiops, a boiler of ironpolilhed on the infide, and about feet in dia-meter, and i in depth, is charged with 1080 lbsof mercury, and 150 lbs of fulphur (or per cent.87.8 mercury, and 12.2 fulphur) a moderateheat is then applied gradually increafing, andaccompanied by fuitable Itirring of the ingredi-ents till the whole appears to be thoroughlymixed and combined. The black fulphuret ofmercury thus formed, is then removed from theboiler and pulverized. In order to convert thisinto cinnabar, three large earthen fublimingpots are placed in a furnace, and graduallybrought to a red heat by means of turf: at thistime the cover of each (which confifts of a Am-ple fquare plate of iron) is removed, and thecontents of an earthen veffel holding about apint and a half of ethiops, are poured into eachpot. In a few feconds a column of flame rifesout of the pots, to the heighth of five or fix feet,and, as foon as it begins to lefl'en, the furtherefcape of the contents is prevented by puttingon the iron cover. In a fhort time after, a fe-cond charge is poured in, to which fucceeds athird, and fo on, till at the end of thirty-fourhours the whole of the ethiops has been equallydivided between the three pots, making 410 lbs.for each. The fire is now kept up as fteadilyas poffible for thirty-fix hours longer, in orderto accomplifh the fublimation, care being takento ftir lip the materials at the bottom of theveflels at lead once every half hour, by an ironrod made for the purpofe and introduced at thetop. At the fame time the workman afcertainshow the procefs is going on by the flame whichappears when the cover is removed if it rifesto the heighth of two or three feet, the heat istoo great, as on the other hand it is too feebleif the flame only lightly quivers about the mouthof the pot; the proper temperature is markedby the flame rifing vigoroufly, yet not exceed-ing three or four inches in heighth. When thelaft thirty-fix hours are expired, the furnace isextinguifbed, and the whole allowed to cool:the fubliming pots are then taken out, the ironhoops with which they are bound are knockedoff, and the pots themfelves are.broken ; the cin-nabar is found fublimed in the upper part of theveffel to the amount of 400 lbs. being iolbs. lefsthan the ethiops that was put in: or in otner

u Ann.de Chem. iv. p, *5.

words, the lofs of weight fuftained by the coi>verfion of ethiops into cinnabar, amounts to 2§per cent.

Cinnabar when re-fublimed undergoes noalteration except that a variable though largeproportion is loft, owing to the combuftion ofthe fulphur and volatilization of the mercury.If cinnabar' inftead of being heated in clofeveflels, is put into an earthen teft, and heatednearly to obfcure red, a total decompofitiontakes place; the fulphur is converted into ful-phureous acid, and the mercury flies off' in theftate of vapour. Long expofure to air apdmoifture feems to have no fort of aCtion on cin-nabar or ethiops ; but they are both decompofedby dry diftillation with barytes, lime, and thefixed alkalies, and with the following metals,iron, copper, tin, lead, filver, cobalt, nickel, bif-muth and antimony. In all thefe cafes the ful-phur of the cinnabar combines with the addedalkali or metal, while the mercury paffes over inthe liquid ftate.

A remarkable circumftance attending the de-compofition of cinnabar by iron filings, is theproduction of an odour refembling that of ful-phuret of ammonia according to Sage, and ofammonia according to Beaume : this odour isfo ftrong and permanent in the balloon receiverof the diftillatory apparatus, that it remains veryperceptible for feveral days, even though theveffel is expofed to the open air. The ammoniahowever thus developed, is in all probabilityneither formed by this procefs nor liberated fromthe cinnabar, but from the iron filings, for, ac-cording to the interefting experiments of Dr.Auftin (fee Ammonia, p. 67) it is readilygenerated by expofing moift iron filings to anazotic atmofphere.

In the moift way none of the acids have anyaCtion on cinnabar, except the concentratedfulphuric and the nitric : the former oxygenatesthe mercury and converts it to fulphat, fulphu-reous acid being difengaged ; the latter oxyge-nates both the mercury and the fulphur, nitrousgas being given out, and fulphat of mercurybeing the refult.

If a folution of either of the fixed alkalies ina perfectly cauftic ftate, is boiled almoft todrynefs upon pulverized cinnabar, an extremelynaufeous odour is difengaged, the alkali becomesmore or lefs charged with fulphur,'and globuies ,of running mercury are produced.

The component ingredients of fublimed cin-nabar are mercury and fulphur, in the conftantproportion, according to Prouft,* of 85

* Jeura. dc Pkyf. liii. p.