■*!TSiA*»***_ HI^H

Book II.

Of METALS.

Pyrites is a Sort of Copper Mar-Lemery, cafite, or hard Stone, heavy, whichfends forth Sparks of Fire uponftriking it with Iron of a grey Colour, inter-fpers'd with little, yellow, Alining Streaks:It is found in the Copper Mines in Italy,from whence they draw the i{oman Vitriol.

To get the Vitriol out of this Stone, it isneceffary to expofe it to the Air for feveralMonths together, that fo the Acid getting in-fenfibly into the Pores may rarify its Parts,and render its Salt more diffolvable, by thisTime it is converted in a Manner to a Chalk,from whence they extract the Vitriol, bywafhing it feveral Times with Water, andmaking Evaporations and Chryftailizationsas are neceffary, and as they do in the makingof Saltpeter.

The Pyrites is deterfive, aftringent, defic-cative, digeftive, refolutive, and to be ap-plied outwardly.

Pomet.

22 Of Lead Oar.

\/\f E have three Sorts of Lead* " Oir that differ one from theother, only according to the Digefticn theyhave receiv'd in the Bowels of the Earth.The Firft, that is to fay, that which has re-ceiv'd the leaft Heat, and by Confequence ismod weighty, is that which has the Nameof Lead Oar, and is made into Lumps call'dPigs, by the French, Salmons.

This Lead Oar is a weighty Mineral, eafyto break to Powder, and difficult to melt,which is taken out of the Mine in Pieces ofdifferent Bignefs, fometimes clean and neat,foroetimes mix'd win Stones, refembling acertain Sort of Marble.

This Lead Oar being broken, parts intoIhiaing Flakes, of a White, enclining to Black,very like the Shoots of Antimony.

The Englijh melt this Lead, and after-wards caft it into Moulds of the Shape wefee the Pigs in. The Lead Oar is of noother Ufe in France but for the Potters, whomake ufe of it, having firft reduc'd it toPowder to varnifli the Earthen VelTels of agreen Colour with it.

Although this Merchandize be of no greatConfequence, yet great Care mult be takenconcerning it ; for if there fhould chance to

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be any other Metal in it, as there is foundto be too often, it would fpoil all the Pot-ters Ware, to the great Trouble ofhim that fold the Commodity ; for this Rea-fon you fhould never fell it to the Potters,without fhowing it them Piece by Piece, andtaking a Note under their Hand, that theyare fatisfied to avoid farther Trouble.

ThsLeadOar that has the requifiteQualities,ought to be in large Pieces, heavy, with finefhining Scales, as if fat, that is to fay, eafilytradable. In a Word, the moft approach-ing to Tin-glafs that it can poffibly; andreject that which is full of Stones and Dirt,or Gravel, as good for nothing, as well asthat which is mixt with the Lead Oar of thefecond Sort that I am going to fpeak of.

The Lead Oar of the fecond Sort is lefsweighty, and much harder than that before-mention'd, and being broke is of a MoufeColour, of a coarfer Grain, and fmoothwithout, in fome Meafure refembling theblack Lead ; which (hows that it has not re-ceiv'd Heat enough to be converted into theblack Lead Oar. This Quality makes thisLead Mineral to be entirely reje&ed, as be-ing of no Ufe : And this Quality is oftenfound in the firft Sort, which caufesfomuchTrouble to the Workmen, becaufe they canno more melt it by the Fire than they cando Marble, and it fpoils all their Work.However, I mull take Notice, that fomeAlchymifts defire it to draw their Lead outof it ; for they pretend that the Lead drawnfrom it is more ductile and clofe than commonLead is found to be. Others will have itthat there is fome Silver in it which I leaveother Perfons to try ; but as it is feldom us'dI fhould not advife any Perfon to furnilhhimfelf with any Store of it.

The third Sort of Lead Oar is very muchus'd, and 'tis that we call Black. Lead, orCrayon, becaufe the moft perfect of it fervesto make Pencils to defign withal. The An-cients gave it the Name of Plumbago, and ofSea Lead, becaufe they pretend they took itfrom the Bottom of the Sea j Foreigners callit Potelot.

We have at Paris two Sorts of Black Lead,to wit, the Fine and the Common. TheFine to be perfed, and in good Condition,fhould not be heavy, of a black finning Sil*yer Colour, not too hard nor too folc, c,

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