Of counterfeiting precious Stones. 187

into the fire, when it is cold: for if you do otherwise, it wiU break in pieces; whichyou must prelently remove frem the rest; for those that are broken,will break others.But that they may be the more casier prepared, when they begin to be extenuated,I make use of this invention. There must be prepared two plates of iron, of ahand square , and the thickness of paper.. Double one of them, that it may receivethe other within the folds of it: so that they may receive the plates of C opper in themiddle, and enclose them on ail sides, that they can neither flip out, nor any dustor ashes fall in, to stick to them. WheD you have thus enclosed the Copper plates,put them into the fire , and heat them; then take them cut with iron tongs, andshaking off the ashes, beat them with your hammer till they are cold , and so theywill become thin and fine rays. But while you are beating one, set others to heat;and do this eight times over,until you have hammer’d them very thin,and made themfit for your purpose. It will be worth your labor to look often upon them, to fee ifany be broken in the working , for they will break their fellows. But because theyarewont to grow black in the working, and foul, so that they oftentimes deceivethe eye- therefore ic is fit, that you have a pot of water ready, with an equal quan-tity of Tartar , and fait in it, and let it boil over the fire: Put into it your rays, andstirre them about continually , till they be boiled white. Then take them out, andwash them in a pot of clear water, till they be very clean : then dry them witha linnen cloth, and then heat them , and beat them on the anvile again, as before,until they spread into rays, as thin as leaf-gold When this work is to be done, thehammer and anvile must be as smooth, and polished, and bright, as a looking-glass;which yon may effect in this manner. First of all, bold them to the grinde-stone,wherewith they grinde knives, until they be smoothed and planed : then rub themwith fine sand, and Pumice-stone ; afterwards glaze them with a wheele , and polishthem with a plate of lead, and powder of emerald: if you use any other art, youwill bat lose your labour. Thus in two days your work will be finished, that is, byheating your plates, eight or ten times, and preparing them, and by whiting themfour times at least: Finally, examine them all, whether they be whole, and of a suf-ficient thinness : so that if any remain too thick , they may again be brought to thehammer and perfected. But I must advertise you, that the thinner they grow, theless time they must lye in the fire, because they will presently melt: and so also inthe water, because the salt will eat into them. At last, cut them with sheares intosquare pieces, that they may be more convenient for use.

Chap. XL

Hew leaves of Metals , are to be peltjhed.

T He plates being thus thinned and finished, we will fall to polishing of them. Butfirst we must provide tools, wherewith to perform it. Take a plate of Copperof a foot in length, and a hand in breadth, most exquisitely burnished,that it may beas smooth as a looking-glass: bow it either with your hand, ora hammer, by littleind little, into the form of » semteyUnder. Then turn a piece of wood, so that it maybe equal, and fit for it in every part, and be received into the convexity of it, wherebeing fastned with four nails at the corners of the plate, it may remain stedfash Fixthis wood upon a little frame,with two bars of a foot height, fastned to the ends ofit. Now we will begin to burnish the plates ; which must be thus done: providechalk made into fine powder, after this fort - take some beaten clay, wrap it in a cleanand indifferently fine cloth, and put it into a washing bowl full of water; stirre itiboar here and there, in the water, that the finest part may be washed through,andthe courser remain in the cloth : then pat the new chalk into the cloth again ; stirre itand strain it till it all pass through the cloth, and then suffer the water to settle, andfeirefe it through a strainer; onely changing the water, until no gross settlement re*main : Then lay the cloth over the mouth of the vessel, which must receive it, and tieit uack on: so strain it, that you may be the mote sure, that nothing but what is very■ac can pass through: then press out the water, and reserve the chalk. Lay this

Dd: clay,