Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/812

 Z I N

Z I N

This water can only dcpofvt fo much copper as it before con- tained, in the folution ; and this appears upon experiment to be much lei's than might have been imagined, the quantity being no more than in every pound fo much as can be con- tained in about two fcruples of vitriol ; that being the ut- moft quantity feparable from it, With all the art that could be ufed. Thofe people are therefore greatly miftaken, who fuppofe, that if ever (b much iron be put into the water there will be as much copper precipitated in its place. The quantity of copper, however, annually obtained in this man- ner is confiderable, as the waters are confiderable in quan- tity. Phil. Tranf. N°. 479. p. 3^,

ZIMEX, a word ufed by fome of the old chemical writers, for verdigreafe.

ZINARIA, a word ufed by the Arabians, for a kind of vitiated bile, called asruginous bile.

ZINC. See the article Zinc, Cycl. and infra.

ZINETUS, a word ufed by Paracelfus, as a name for one of the brafs-like marcafites.

ZINGAR, a word ufed by fome of the chemical writers for verdigreafe ; and by others for the flos sris, or flowers of copper or brafs.

ZINGI, in the materia medica, the name of a feed, fometimes alfo called the anifum ftellatum, or ftarry-hcaded anife. J. Bauhln. V. 1. p. 586.

ZINGIBER. Seethe article Zinzieer, Cycl. andSuppl.

ZINGNITES, or Zingrites, a ftone defcribed by Albertus, Ludovicus Dulcis, and other writers of that time, and faid to be of a cryftalline tranf parence ; they give us no farther defcription of it, but attribute a number of imaginary virtues to it.

ZINIAR, a name given by fome of the chemical writers, for verdigreafe.

ZINIAT, a word ufed by the old chemical writers, to exprefs cither the action of fermentation, or any thing that is ca- pable of exciting it in bodies.

Z1NK, (Cycl.) in natural hiftory, the name of a very remark- able foffi'le fubftance, refembling bifmuth in appearance, but of a bluer colour.

It is a very remarkable mineral, and one that has never been well underftood as to its origin, till of late ; for though the World well knew of a long time both Zink and lapis cata- minority and knew that both of them had the remarkable property of turning copper into brals, which one would think might have given a hint to the difcovery of a natural alliance between them ; yet have they been ever treated of as two different fubftances, by the writers on thefe fubjects ; and Dr. Lawfon was the firffc who ever publicly declared, and proved, lapis calaminaris to be the ore of Zink. Seethe article Calaminaris Lapis.

Zink is generally confounded with bifmuth, though in realitv a very different body ; but the regulus of thefe two minerals having a very great external refemblance, the vulgar have not diftinguifhed them ; and hence we hear of many ores of Zink in the lefs accurate writers, all which are truly the ores of bifmuth.

The lapis calaminaris is the true and general ore of Zink, yet that mineral is not confined to this ore alone, but is mixed in great abundance in its diffeminated particles among the matter of the ores of other metals, particularly of lead. Our artificers have long been acquainted with Zink, under the name of fpeltcr ; but none of them till of late have ever been able to make any guefs as to its origin. We have much Zink brought to us from the Eaft-Indies, under the name of tuienag ; yet no body ever knew from what, or how it was produced there ; and all that was heretofore known of it was, that among that ftrange mixture of ores which the great mine yields at Goffelaer in Saxony, when they were fufed for other metals, a large quantity of Zink was produced ; but Dr. Lawfon obferviug, that the flowers of Zink and of lapis calaminaris were the fame, and that their effects on copper were the fame, never ceafed his inquiries till he found the method of feparating Zink from it. The pure Zink is a folid metal-like body, of a bluifh white, and fomewhat lefs brittle than bifmuth, efpecially when gently heated, and moft of all the metallic minerals ap- proaches to malleability : It melts in a very fmall fire, and in a ftrong one takes fire, burning with a bluifh-green flame, and fubhming into white flowers, which are with difficulty reducible again into the form of Zink .-? In an open fierce fire, it wholly flies off in vapour.

There is great reafon to believe, that all the Zink or tutenag brought from the Eaft- Indies, is procured from calamine; and we have now on foot at home, a work eftablifhed by the difcoverer of this ore, which will probably make it very ibon unneceffary to bring any Zink into England, as we have great plenty of the calamine. Hill's Hift. of Foff. p. 626.

rhe manner of extracting Zink from the lapis calaminaris, is this : The lapis calaminaris muff be finely pulverized, and well mixed with an eighth part of charcoal -duff, and put into a clofe retort to" prevent the accefs of the air, which would inflame the Zink as it rifes. The retort is to be placed on a violent fire, fufficient to melt copper. After

fome time the Zink rifes, and appears in the form of me- tallic drops within the neck of the' retort. Whun the veffel is cool, it muff be taken out, by breaking off the neck of the retort. Marggraf. in the Mem. de l'Acad. de Benin, 1746.

Mr. Marggraf obferves, that different forts of lapis calami- naris, fuch as the Polifh, Hungarian, and Englifh, afford different quantities of Zink. And that a particular kind found in England, gave near half its weight of Zink. This extraction of Zink, does not always fucceed. Some calamine from Bohemia and Aix-la-chapelle yielded nothing. But then, as thefe kinds did not tinge copper with a yellow colour, nor produce any change In it, he thinks them not true calamine. Hence he concludes, that a Hone which mix- ed with charcoal, and expofed to the moft vehement action of a clofe fire, produces no Zink ; or which, in an open fire, does not produce brafs with copper and charcoal, is not true lapis calaminaris.

Ztnk, produced in the manner above-mentioned, may be hammered into thin plates ; which cannot be done with the common Zink. We muff refer to the learned author for feveral other obfervations relating to Zink, and its flowers. See the article White Vitriol.

Mr. Boyle tells us he diflblved Zink in an urinous fpirit, and then put to it a quantity of acid fpirit ; but though a manifeft conflict arofe, yet the Zink remained diffoived in the mixture. Boyle's, Works abr, Vol, 1. p. 521. Zink may be diffoived, not only by aqua-fortis, aqua-regia, oil of vitriol, fpirit of nitre, fpirit of fait, and other mineral menftruums ; but alfo by vegetable fpirits, as diffilled vine- gar j and by animal ones alio, as fpirit of fal armoniac, and fpirit of human blood. Ibid. Vol. 3. p. 478. Mr. Boyle obferves, that if the feveral folutions of this mi- neral be comparedi it will fhew what a variety of taftes is producible from one infipid body, by affociating it with dif- ferent menfirua. Works abr. Vol. r. p. 541. The fame author tells us, that by the help of Zink, duly mixed after a certain manner, he has given copper as rich a golden colour as ever he law in the belt gold. Ibid. Vol. 2. p. 180.

Zink gains weight by ignition. Boyle, ibid. p. 391. §.. ir. But quaere the circumffances of the experiment ; ior in the fame book, p. 395. §. 26. the filings of Zink put in a bolt- glafs with a flender neck, and Jet upon quick coals for four hours, loft weight.

Flowers o/Zikk. The flowers of Zink are a fubffance fa- mous in the writings of the chemifts, who have led their followers into a thoufand errors by the names by which they have called them.

Some have called them talc, and a folution of them in vinegar, oil of talc ; to which they have attributed very ex- traordinary qualities. Some have fet the ignorant upon a fruitlefs attempt of extracting an oil from V enetian talc, to do all the things they have commemorated of this oil. Others have called thefe flowers thefericum : Others the aquaficca philofophorum ; and others the philofophic cotton. The moft Ample and eafy way of obtaining the flowers of Zink pure and white, is this : Melt the Zink in a tall cru- cible inclined in the furnace in an angle of 45 degrees or thereabouts ; let the fire be moderate, little ftronger than. would be neceflary for the melting of lead. If the Zink is left in this ftate without being ftirred, it forms a grey cruft upon its furface, and becomes calcined by degrees under.it into a granulofe white fubffance ; but to have the flowers, the matter muff be ftirred from time to time with an iron rod, and this cruft broken as often as it arifes ; there will then after fome time appear a bright white flame, and about two inches above it there will be found a very thick fmoak, and with this there will arife a quantity of very white flowers,

- which will fix themfelves to the fides of the crucible in the form of fine cotton.

Thefe flowers are to be feparated at times, and by careful management there may be collected from the Zink a greater weight of flowers than its own weight, when put into the fire. In working four pounds of Zink in this manner, there- will be only about an ounce of a calcined earthy matter left at the bottom of the crucible, and the quantity of flowers will be about two drams and a half in each pound, more than the quantity of Zink ; befide that, it is eafy to conceive from the manner of making them, that a great quantity mutt have been carried away with the fmoak. And this is not to be prevented, fmce if the veffel be clofed to keep in the fumes, the external air being denied free accefs, the fubli- mation immediately ceafes, and no more 'flowers can be obtained, till the veffel is again opened, and the air ad- mitted.

The fumes of Zink have a ftrong fmell of garlic, and are very noxious to the lungs. The reducing Zink into thefe flowers, is the deftroying it abfolutely as to its metallic form; for none of the methods ufed by chemifts to bring back me- tals to their original ftate, are able to bring thefe flowers to Zink again.

Mr. Hellot, of the Academy of Sciences of Paris, who has given a very accurate analyfis of Zink, has tried the diffe-