Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/50

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semains after the flower is fallen. The flower confifts of a iingle petal, in form of a fhort cylindric and fomewhat open- mouth'd tube. The rim beyond the middle is divided into five fegments, the jags being open, obtufe, bent backward, and covered with a woolly hahynefs. The ftamina are five fhort and tapering filaments, and the anthers are acute, bifid at the bafes, and erect. The germen of the piftil is of a conic form ; the ftyle is cylindric, and nearly of the length of the flower ; and the ftigma is bifid and comprefled. The fruit is an oval capfulc, containing only one cell, and iur- rounded with the cup. The feeds are very numerous, fmall, and of an oval figure. Linnai Gen. Plant, p. 64.

MENTZELIA, in botany, the name of a genus of plants, the characters of which are thefe ; The perianthium confifts of one leaf, divided into five expanded fegments. Thefe are lanceolated and deciduous, and terminate in a very long ger- men. The flower confifts of five ovated petals, which ftand expanded, and are fomewhat longer than the fegments of the cup. The ftamina are numerous erect fetaceous filaments ; the anthers are fimple ; the germen of the piftil is of a cylin- dric figure, and is extremely long, and Hands under the cup ; the ftyle is fetaceous, and of the length of the flower; the ftigma is fimple ; the fruit is a long capfule, of a cylindric clavated form, containing only one cell, in which there are lodged numerous fmall and roundifh feeds. Linn a i Gen. Plant, p. 236. Plumier* Gen. 6.

MERCATORUM Fejlum* among the Romans, a festival kept by the mercantde people on the ides or 1 5th of May, in honour of Mercury, to whom they facrificed a fow; then fprinkl'mg themfelvcs with the water of a fountain called aqua mercurii* they prayed the god to profper their trade. Danet* in voc.

MERCURlALlS, Mercury* in botany, the name of a genus of plants, the characters of which arc thefe : The flower is of the aj)etalous kind, confuting only of a number of ftamina placed in a cup. Thefe flowers are barren, and the embryo feeds appear on other plants of the fame fpecies, which have no flowers. Thefe finally become a fruit compofed of two capfules, containing a roundifh feed.

The fpecies of Mercurialis enumerated by Mr. Tournefort„ are thefe : 1. The tefticulated Mercury* commonly called the male Mercury. 2. The fpiked Mercury* commonly, but improperly called, the female Mercury ; this being truly the male, and the tefticulate the female, thofe tefticles con- taining the feeds. 3. The mountain tefticulate Mercury* called Cynocrambe* or Dogs Mercury, 4. The fpiked cyno- crambe, or dogs Mercury. 5. The fhrubby hoary tefticu late Mercury* called Pbyllon. 6. The fpiked Pbytton, or ftirub hoary Mercury. 7, The Portugal fhrub almond-leav'd tefticulate Mercury. 8. The fpiked almond-leav'd fhrub fpiked Mercury. 9. The round-leav'd three-mouths Mercury* the male and female kinds. Tour?!. Inft. p. 534. Mercurialh is of an emollient nature, and eaten in the man- ner of fpinach, which, when cultivated in a garden, it greatly excels. If eaten largely, it opens the bowels. A cataplafm of the leaves is much recommended in pains of the limbs, in tumours, and even in ulcers, which it cleanfes and difpofes to heal. Poor people in country places ufe it as a cataplafm for the rheumatifm, and even for the gout, with luccefs. In the {hops, it is chiefly kept as an ingredient in decoctions for glyfters.

MERCURIFICATION, in metallurgic chemiflry, the ob- taining the Mercury from metallic minerals in its fluid form. For the effecting this, thofe who have been engaged in thefe refearches have propofed three methods. The firft is by means of a certain mercury, fo prepared as to have a diffolv- ing power, by which it could take up the mercuries of metals in the fame manner as water diflblves fait from afhes. The fecond is by means of certain regenerating falts, fuch as fal armoniac, which are to detain the more earthy parts of me- tals, and leave their mercuries feparate or feparable from them by fublimation or otherwife ; and the third method is by means of a large lens or burning-glafs, in the focus whereof if any metal be applied, its mercurial part is faid to feparate and go off in fume, which when collected and con- demned, appears to be running mercury. Shaw's Lectures, p. 160. The firft of thefe methods would be very eafy, if the proper mercury were to be readily produced ; the fecond is extremely laborious, and requires much patience and reiteration. But the third feems eafy enough, and practicable to advantage, when a glafs of three or four foot in diameter is at hand, the fky ferene, and the fun {nines ftrong.

MERCURY (Cycl.) — The manner of feparating Mercury from its ore, when not fulphureous, is this : Take a pound of the ore beat to powder; this with the affayer muft ftand for one centner ; put tins into a glafs retort, coated half way to its neck, which muft be long, and turned back with fuch declivity, that a glafs recipient may be ap- plied perpendicularly to it. The retort muft be of fuch a fize, that the belly of it may be filled nearly two thirds with the ore ; and muft he placed fo that nothing of the fluid, adherent to the neck of it, may fall into the cavity of the belly, but that the whole may run forward into the re- cipient, which muft be filled with cold water : This muft be 4

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fo placed as to receive the nofe -of the retort ; L bout one half inch into the water. The joints need not be luted. Cra- mer's Art of Aflaying, p. 350.

Let the retort be furrounded with burning coals, placed at a diftance, left it burft ; by degrees bring the coals nearer, and at length clofe to the retort ; add frefh charcoal, and make it flightly red hot. When this fire has been continued an hour, take off the recipient, firft ftriking the neck of the retort to throw off the loofe drops that may hang there ; and in the bottom of the water you will find the Mercury. This pro- cefs may be alfo performed in a fand heat ; but the bottom of the retort muft touch the bottom of the veffel that contains the fand, and that be made red hot. The Mercury is to be feparated from the water by filtration.

The fuppofition of a fympathy between Mercury and gold has been the great bafis of the attempts of the alchemiits of all times, toward the making gold of it. But if they mean that the common Mercury has this fympathy with gold, the con- trary is proved by that remarkable pioccfs, in which it appears that Mercury will incalefce with that metal. If they mean thatr Mercury which they call the feed of metals, it is hard to offer any thing in argument againft it, this being a fort of ideal fub- ftance which no body has yet fcen. It is much difputed by the alchemifts, whether there be or be not any fuch thing as Mer- cury that will heat or incalefce with gold, or produce a fenfi- ble heat in the mafs, on being only fimply mixed with that metal reduced to fine parts. It has been faid by fome, that thofe Mercuries which they call Mtrcurii Corprum ; that is, fuch as have been extracted from the compleat metals by certain procefles, which they keep as inviolable fecrets, wilt incalefce on the mixture with gold ; and on this they build their procefles. But the negative part of the queftion is more ge- nerally maintained, the famous Mercuries of metals being held as non-entities with them ; and even the fearchers after tranf- mutation of metals have in general acknowledged, that they themfelvcs never faw any fuch incalefcence of Mercury with gold, though they had heard others fpeak of it as a thing they had (een. A Mercury, however, was fome years ago pro- duced before the Royal Society, which in the hands of the prefident himfelf, on the faireft trial, did incalefce with that metal. Phil, Tranf. N°. 122.

Among the feveral methods recommended for the fixing this fluid metal into folid filver, oil of talc, and oil of the hu- man faeces, are the moft ftrongly affirmed to be the infallible mediums. The firft of thefe which has been fo much mifun- derftood, by realbn of its name, as to be fearched for in the {tone talc, is truly an oil prepared from the flowers of zink. See the article Oil of 'Talc.

The other is required to be clear and colourlefs as water, and without any ill fmell. Thefe were qualities fo difficultly to be found in an oil of that fsctid matter, that both the on* and the other of thefe oils were looked upon by many as im- practicable procefles. But after the firft had been made by two or three chemifts, Mr. Homberg at length hit upon the laft, but without finding any the lealt tendency to fuch an effect in it, or any change at all produced by it on Mercury y after ever fo long digeftion, or ever fo many procefles. Mem. Acad. Par. 1711.

If Mercury be diflblved in aqua fortis, fo that the folution be clear and total, and if whilft it is yet warm fome lead filings be poured in by degrees, the lead will be precipitated into a white powder, and the Mercury reduced to a mafs of running qu'ick-filver. Boyle's Woiks abr. vol. 1. p. 318. Mercury may be diflblved in vegetable acids. This is done- by reducing it to a calx by a long digeftion. A fcruple of this calx may be diflblved in an ounce of diftilled vinegar, in a boiling heat. The folution being viltred and expofed to the cold, will in part be changed into fine cryftals. This calx diflblves likewife in the juice of lemons, riieniih wine, and other vegetable acids.

But a precipitate of Mercury made from its folution in aqua fortis, by means of oil of tartar per deliquiu?n* and well edul- corated by boiling water, is more eafily diflblved in diftillcd- vinegar. It may even be diflblved cold without digeftion. Marggraf. in Mem. de L'Acad. de Berlin, 1746. Boerhaave has obferved, 1. that quickfilver, however well purified, yields always a foft black powder, of a fharp braiiy tafte, when long expofed to violent conq-uaflation, or to a degree of heat, twice as great as that of animals. 2. Heat, near as ftrong as what is ncceflary lor dirtilling quickfilver, changes the greater part of Mercury* if not all of it, into a heavy, fhininy;, red, friable powder, of a fharp naufeous tafte, which long and violently disorders the human body, and difpofes it to excretions. 3. The fluid quickfilver remain- ing after this red powder is feparated, is more fluid, and of lefs fpecific weight than common .Mercury. 4. All the black, and near the whole red powder, can be brought into the for- mer fluid ftate, by a more intenfe heat ; and this revivified quickfilver enjoys all the properties of common Mercury. The experiments on Mercury above-mentioned were fent by Boerhaave to the Royal Society. He fent an account of others to the Royal Academy of Sciences at Paris. The con- cltifions from thefe experiments are, that he could not change quickfilver into any other metal, and that no quickfilver was