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[Section. 1] I HAVE mentioned before, That a dif∣ference is to be made among Oars, be∣cause some are harsh, hard-flowing and raw; as also that some are soft-flowing and mild: The soft-flowing Oars are thus to be tryed for Silver: Take the Oar, grind it with an Hammer upon a broad Iron,
(fitted to that purpose) as small as pouder, weigh of it a [Section. 1] Centner (with thy Assay-weight) put it on a well-made Test, and mingle eight times as much of Lead in Grains among it, and set in a warm Assay-Oven, and presently make it hot, and set Coles before the Ovens mouth, so the Lead will begin to drive and turn quickly to Slacke or Dross, and when it hath stood so long in the Proof-Oven, that the Lead upon the Test is all covered over with dross, then it hath dross enough; (this is called Boy∣ling up or Ʋp-boyling) then take an Iron hook, lay it that it may be a little red hot, and stir the Oar with it clean∣ly about, which is done for this Reason, that if there should stick any of the Oar on the sides of the Test, it may be made loose, and that the Lead also may work on it, and consume it: After the stirring, let it stand a while, and then take it out of the Assay-Oven, and pour the Lead and dross upon an Iron-plate, in one of the lit∣tle holes that are to be made upon the Plate, and let it cool, and then separate the dross clean from the Lead, so is the proof of the Ʋpboyling ready, which is done in the space of about half an hour, afterwards set Coppels in the Assay Oven, and let them glow well for half an hour, (and this is called Nealing) and upon these well neal▪d Coppels put your Lead so wrought, which hath been boi∣led up, and make it warm that the same may first begin to work, and when it begins to drive, then keep the fire not too high, that the Lead or work may drive well, and go off upon the Coppel in a conveient heat, and so the Lead will all be drawn into the Coppel, and the grain of Silver will remain alone, (provided that the Oar hath Silver in it) upon the Coppel, although it be very small, then take the Coppel out of the Assay-Oven, and take with your Pincers the Grain from it, so is the proof finished: Now, how this Grain is to be weighed, with the Assay-Scales, it doth require a special dili∣gence;
and of this you shall be more exactly instructed afterwards.
[Section. 2] You shall Assay these harsh and hard flowing Oars in this manner, Take the Oar ground small, and weigh of it a Centner with your Assay-weight, put it on a good Test, and add to it its due weight of Lead, to wit, Four∣teen Centners: set it in an Assay-Oven, and give it pre∣sently heat, that the Lead in the Assay-Test may begin to drive, as you have done with the soft-flowing Oars, and when the Lead begins to drive, then let it be cold again, which will be, when you do shut the lower mouth∣hole, and do open the upper, then will the Oar rise, and come to be roasted upon the Lead; when it is roasted e∣nough upon the Lead (that is when it is seen to leave smoaking much and begins to slacke) then maist thou give it heat again, as much as can be. This happens when you do lay Coals before the upper Mouth-hole of the Assay-Oven, so the great heat will force it, that the Oar will turn to slackes, but it doth slacke small and not easily, and when the Oar is almost boyled up, and hath slacked finely, then stir it cleanly with an Iron-hook, let it stand again a pretty while in the Oven, and when all is turn'd to fine slakes, then pour it as before upon a Plate hollowed, or let it cool in the Test, and beat the slackes from it, so is the proof of up-boyling ready.
[Section. 3] In such manner, almost, may all Pibbles or raw Oar be boyled up, and this is a right and good way to do it, but the up-boyling is hardly done in an hour, yet it may be done sooner in this manner; when you have weigh∣ed your Oar, and set it on the Test without Lead in the Assay-Oven, give first some heat until the oar upon the Test is roasted, and smoak no more: then set the Lead, (as much as belongs to the Tryal) upon the Test; give it a great heat, so will the Oar boyl up something easier, and in less time than if it should have been roasted upon the Lead.
[Section. 3] Although there are some that believe such a Tryal in which the Oar also is roasted without Lead) is false and not right, yet I do give this Information, That I have oftentimes, (with one sort or other) tryed both wayes, and I do truly affirm, That I have found no difference: But there must be a Care taken, that when the Oar is set alone upon the Test, that it may not be put into a violent suddain heat, because such an heat doth raise the small Oar, and doth cause it to dust away, especially when the Oars are stony, for it makes the Tryal false (this excepted) I know no fault, but be carefull and you will find it true.
[Section. 4] Some have also another way to try raw mild Oar; as thus, They set first the Test in the Oven, that it may glow, and then put the Lead in it, and let it by it self slack pretty well, after that put upon the slack'd Lead, the weighed Oar in small Papers, so the hot Lead, and hot Slack will draw the Oar quickly to it self, and will not let it rise much, or boil up very well: this way I also like, only that in drawing the Oar upon the hot Lead, (especially the mild Oars) it will dust, and when there are many Proofs to be made together, there will some∣thing be neglected, and the Proofs may become false.
[Section. 5] If one doth know the Nature and Property of such Oars as will not easily boil or slack, but remain upon the Lead (for so will the Chalk-stones) the gross and raw blind or Cobolt, the mispeckle, as also the mild and fresh Pibbles and water-pibbles which must (assoonas they are weighed) be mingled with Flus or Lead-glass (as hath been before mentioned) which vvill hold the raw Oar, and doth not suffer it to rise high, because it hath help by the Lead-glass, so that it vvill become soft Slacks and slacks vvell, and boyls up clean, as may be seen in melt∣ing: harsh Oars (vvhich in Ʋp-boyling each one by his proper addition may be helped) that they vvill be vvell
separated, or else there vvill remain some Silver in the slacks, and so there vvould be some Dammage.
[Section. 6] In S. Joakims Valley (so called) there are Oars bro∣ken, vvhich are called Coppery-Oars or flaky Oars, vvhen they are once boyled up, the Work or lead vvill not go off upon the Coppel, but casts up a Ring or border, and eats much in, and makes the Proof false: and vvhen this is knovvn by an Oar, then must the vvork or Lead vvhich hath been boyled up (and from vvhich the dross is separated) be again set upon the Test, and be slack'd again, and then the Lead vvill come off clean and white; This is called, the Lead cleansed of its Foulness, then it must go off upon the Coppel, as before.
[Section. 7] It happens also often, that the gross Sulphury oars do also make the Lead black and harsh, also that upon a well neal'd Coppel it doth not drive, but leap off, which makes the Tryals oftentimes come false, because of its Foulness, such Lead you must once more set upon a new Test or upon the same, and let it slacke again, so will it be white and clean and go well off upon the Coppel, and loose nothing.
[Section. 8] Concerning the Cobolt oars, there are many sorts of them, some fresh and some milde, black and gray, some in trying do go easily into the Lead, but such Lead that comes by Ʋp-boyling from it, is black and red, and it afterwards doth work upon the Coppel, and dissolves, therefore it must after the first Ʋp-boyling, be cleansed again of its Wildness and must be slackd once more, so it will become white, and go clean off from the Coppel: One may also set the weightiest Cobolt Oar in a Test in the Oven, and let the smoak pass away, some of which sort do leave gray Ashes, and some a black grain upon the Test, and the rest will burn all away, but put a lit∣tle Lead to it, and it will easily go in it, and also go
clean off from the Coppel, and is found alike with the other Tryals.
[Section. 9] But some do take it as above-mentioned, That when the raw oar upon the Test is roasted without Lead, the roasting doth take away some of the Silver, and that the gross Sulphur doth carry it away, and they will de∣monstrate it by some volatile raw Flints, and the raw slackestone, which comes from it; which after they are roasted do not yield so much Silver as if they were mel∣ted raw through the Furnace, to which I do yield, and have found the same true: But because the roasting ge∣nerally in the great Work with quantities of oars is done in the naked fire, in which it also must lye several hours▪ contrariwise in the Assay-oven and small Proofs there is but little oar put in, and that in a close Fire is roasted in a short time, I judg for certain, that through such roast∣ing of the Oars in the Assay oven, nothing can be lost of the Silver.
[Section. 10] Some may ask, If this way of using, trying and boyling up of Oars in the Test (and to let them so go off in the Test) be the right way, or no, by which the true worth, and how much Silver the Oar contains in it may be known? To which I answer, That this is the right proving, after which the melting Works may be order∣ed, and set up: But the true worth, how much Silver the Oar hath in it, is not found there.
But to know this, Set a great Coppel (as is used to Copper Assayes for Silver) in the Assay-oven, and neal it well, and put sixteen Centners of Lead in it, let it be∣gin to drive, then put one Centner of the ground-oar, which must be parted into many parts, and put it in small Papers, one after another, when the one part doth come first on it, it will seem stubborn upon the Lead, and vvill cover it all over, but let not this hinder thee; Do it first a little cool, and then hot, so it vvill soon slack in the
[Section. 10] Coppel, and the slacks vvill pass avvay, then set an other part of the Oar on the Lead, and that vvill do like the first, vvhich slackes vvill soon pass avvay, then put in like manner the Oar all singly upon the Lead, and it vvill all pass clean avvay in the Coppel, so that it vvill hardly be discerned, but seem like any other vvork upon the Coppel.
In this manner may all other Works (if they be flow∣ing or harsh, as also melted slack stone and Copper stone) be tryed through; in vvhich you vvill finde a great difference, if you try the other usual Way of Refining, but this vvay cannot be used generally, except of all Oars that are melted, to slacks vvhich are not altogether without Silver; therefore the common way of Assaying (with the Ʋp-boyling upon Tests, of which all slacks do come, which cannot be wholly without Silver) is the best way: I have only mentioned these Assayes, to demon∣strate, That with the same (out of every Oar) the right and full worth of Silver may be found in it, as fully as in the other Common Assayes: For several years, some vvorthy Assayers have weighed the Oars with the Cent∣ner-weight, [Section. 11] which they intended to try upon silver Proofs mingled with Lead-glass, and covered with Salt in a Crucible, and placed it before the Bellows, and did melt it into a Regulus, after which when the Crucible vvas cold, then have they beaten out the Regulus, and toge∣ther vvith the slackes have set it again upon a Test in an Assay-Oven, and caused it to slack fully, vvhich vvay is nothing vvorth, especially vvhen many Oar-Proofs are to be made: then Refiners have soon seen it, and have [ 12] thereupon ordered their Tryals according to our vvay.
Here I must mention also, That vvhen an Assayer hath dayly much to try (to vvhose hands vvithout Question harsh and hard▪flowing Oars come often) and if he be then vvell skill'd he knoweth by much and dai∣ly
Experience and Practice) how each Oar is in the Tryal; therefore when he hath prepared the Oar for Assaying (and so he must because of the many sorts) use a bigger Assay-oven, that he may set several Proofs together at Work, whereby his Tryals may be made the sooner, and must keep this Order, when he will set his Assays in the Oven, if they be 8, 9, or more, he must place them accordingly upon the Assayes, which are prepared in this manner; viz. That always the hard-flowing Oars may be hindmost in the Oven, and that the soft-flowing may stand before: for they are soonest boiled up, and so may be taken out of the Oven without hindrance to those that must be longest in the fire, and then be cast upon an Iron-plate, vvhich Plate must be made thus, It must have as many Holes and Vents as there are Tests to be set in the oven at once: so that each Oar may be poured out from its ovvn hole, that you may not mistake: But if it should happen that (be∣cause of thy many Tryals) you must have above one Fur∣nace, then put all the hard-flowing Oars into one Fur∣nace, and the soft-flowing into the other; othervvise you must stay one Tryal for the other, which would be an hinderance. This vvay of Assaying is at Kuttingburgh (because of the great Oar-Trade in common use there) so that in some places every Week 200 Tryals of Oars are made, and the Contents are delivered to a Dram.
[Section 13] Take Notice, That it is vvith this, as vvith other Tryals, (as was before mentioned) only have a Care that you make use of an Assay-weight which may not be too little, and to have good and quick Scales upon which you may know the weight to a dram, or the fourth part of an Ounce, so then if you do well with the Proof in the Fire, then may you safely and surely give in the true Contents of as many Loths and Drams as you do find, after that one is weighed.
[Section. 14] Further, take Notice, That when thy Tryal is made and that you will draw up or weigh your small proof∣grains, let your Scales be kept in a Case of Glass (that the same may be preserv'd from the Wind and Dust) then put into the one Scale the small grain of Silver, and into the other the grain of Lead (as small as it is) and put as much of the Assay-weight to it, that it may stand even with the grain in the other Scale, when this is done, then change the Scales that are in the Proof-scales, and see if the Scales stand even as before, if then the Proof be found alike on the one side as on the other, and just with the weight, then may the same be judged true, and be given in.
[Section. 15] Such silver Oars as are very rich may also with the Fluss (made of Salt-petar and Argol asshall follow here∣after) be mingled and put into a Crucible and covered over with Salt, and may be melted like unto the Copper Oars before the Bellows, and there will be a silver Re∣gulus, in the bottom of the Crucible (which is not very tuff nor pure, because of other incorporated Metals) the which you may make fully tuff upon a Test, and in this manner the silver is very easily to be had out, but it is not the true Contents, because the Slacks do yet contain part of the Silver in them, the grain also doth not come very fine from the Test except it be done upon the Coppel.
Assaying of soft flowing Oars.
Tryals of harsh Oars.
A quick up∣boyling of Silver Oars
Another way to try raw Oar.
Of Assay∣ing the Cop∣per slacky Oar.
Cleansing of the gross sul∣phury Flints after Ʋp∣boyling.
To try Co∣bolt Oars.
Roasting Oar in the Ovens.
Probation by which the right and full worth may be found.
To try with Lead glass.
When many Oars are▪to be tryed.
To assay to a Dram▪
How to weigh the tryd grain.
To boil rich Oar with Fluss.