Fleta minor the laws of art and nature, in knowing, judging, assaying, fining, refining and inlarging the bodies of confin'd metals : in two parts : the first contains assays of Lazarus Erckern, chief prover, or assay-master general of the empire of Germany, in V. books, orinally written by him in the Teutonick language and now translated into English ; the second contains essays on metallick words, as a dictionary to many pleasing discourses, by Sir John Pettus ... ; illustrated with 44 sculptures.

CHAP. XXXII. How to drive out all sorts of Silver, that it may be Deft, smooth and fine.

[Section. 1] BECAUSE it happens many times that Silver in casting together from an evil smoak (or when happily a little tin comes among it, or, that among the old Silver there hath been tinny, false and gross mixtures,) becomes hard: then is it, as [Section. 2] * 1.1follows, to be made Deft, again: Put the Silver upon a plain Test (which is done over with clean and fine Clar, blow it till the Silver runs and goes well, then add two or three Balls of very clean Lead, according to the quan∣tity of Silver, blow it again until the Silver doth bear the Bellows, and becomes Deft; but you must (in the blowing upon the Test) once or tvvice (with a glovving Iron-Hook) stir the Silver that it may be Deft through∣out, then let it cool, and put it in a Pot together as it plea∣seth you, and take notice, that if somevvhat of the Cop∣per be blovvn avvay, by vvhich the Silver on the content becomes richer, then if it shall retain the Content, vvhich it had before, it must (in the casting again) be helpt by adding so much Copper.

[Section. 3] * 1.2But hard burnt silver, (or other good silver, which might become brickle from a leady Lump) that same Silver (if a little Lead be with it) may (in this manner upon a plain Test) be made Deft without any addition; except it hath too much Lead with it self, then it must

be made upon a plain little Test (as above is taught) by the Silver, burning-pure and Deft.

[Section. 4] Also there may a Flus be prepared to make the Sil∣ver deft, (which doth cleanse the Metals very much:) * 1.3thus, Take sal Alkali, Nitre, Red Argol, and salt Petre, of one so much as of the other, calcine, and dissolve it again in warm Water, and let it go through a filter and coa∣gulate; so is the Flus prepared.

Notes

• * 1.1

  A little Lead Ball.
• * 1.2

  To Brickle hard burnt Silver.
• * 1.3

  A Flus to brickle Sil∣ver.