> 74 -

Natural Mao i c k. Doo^ y.

with sand , till the fume of the sulphur be'removed again: let it boil again as at first,and so it will wax white, that it will endure the fire, and not be rejected for coun-terfeit ; you (bail find it profitable if you do it well; and you will rejoyce, if you donot abuse it to your own ruine.

' ' •" Chap. VIII.

How to make a Metal more weighty,

I T is a question amonsst Chymists, and such as are addicted to those studies, how itmight be that silver might equal gold in weight , and every metal might exceedits own weight. That may be also made gold, without any detriment to the stampor engraving, and silver may increase and decreaf- in its weight, if so be it be madeinto lome vessj. I have Undertaken here to teach how to do that easily, that othersdo with great difficulty. Take this rule to do it by, that

The weight os a Golden vessel may increase ,

without hurting the mark, if the magnitude do not equal the weight. You shallrub gold wx h thin silver, with your hands or fingers, until it may d ink ic in, andmake up the weight you would have it, sticking on the superficies. Then prepare astrong lixivium of brimstone and quick lime, and cast it with the gold into an earthenpot with a wide mouth : put a small fire ULder, and let them boil to long, till you feethat they have gain’d their colour* then take it out, and you shall have it: Oreiiedraw forth of the velksof eggs and the litharge of gold, water with a strong fire, andquench red hot gold in it, and you have it.

Another that is excellent.

You shall bring silver to powder, either with aquafortis, or calx; the calx is after-wards walht with water, to wash away the fait, wet a golden vessel or plate withWater or spittle, that the quantity of . the powder you need may stick on the out wardsuperficies yet put it not on the edges, for the fraud wvll be easily discovered byrubbingit on rhe touch stone. Then powder finely fait one third part, brick asmuch , vitriol made red two parts: take a brick and make a hole in it as big as thevessel is, in the bottom whereof strew alrm de plume: then again pour on thepowder with your work till you have filled the hole, then cover the hole withanother brick, and fasten it with an Iron pin, and lure the joynts well with clay ;let this dry, and let it stand in a reverberating fire about a quarter of a day; andwhen it is cold, open it, and you shall find the gold all oft silver colour, and moreweighty, without any hurt to rhe stamp. Now to bring it to its former colour, dothus: Take Vcrdigreafe four parts, Salammoniack two parts, fait-peter a half part,as much brick, alom a fourth part; mingle these with ihe waters, and washthe vessel with ir: then with iron tongs put it upon burning coles, that it may bered hot :take ir off, and olunge ir in urine, and ir will regain the coir ur. If it shinetoorru:h,and you would have it of a lower colour, the remedy h towel it in urine,and b t ir stand on a plate red hot to cool. But thus you shall make vitriol very red;put it i"to a vessel an er ed with coles, and boil it till it change to a most bright red :take it our a^d lay it aside , and do not use it for an ill purpose. We may with thefragments of brass

Do this huf ness otherwise:

That shall supply the place of silver, and it shall become too weighty: Or otherwise,melt two parts of hrass with silver, then make it into small thin plates; in the meanwhile make a powder of the dregs of aquafortis , namely of salt peter and vitriol,and in a strong melting vessel, put the plate and the powder to augment gold , fillthe vessel in a preposterous order. Then lute the mouth of it, and let it in a gentlefire half a day : take it off, always renewing the fame till it come to the desiredweight. We have taught how to increase the weight, and nor butt the falhion