Holograph draft of MINT00173 (Mint 19/1/109)
Of the fabrication & triall of the moneys of Gold & silver by the assay.
Assaying & refining are operations of the same kind. The Assayer refines a small piece of any mass of gold or silver & by the decrease of its weight makes his report. And if there be no decrease, that is, if the mass be of the same fineness with the refined Assay-piece, he reports (or ought to report) it two carats better then standard, or twenty & four carats fine: & this \is/ fine gold in the sense of the Law. The Assay-piece therefore when the Assayer works exactly becomes fine gold or fine silver in the sense of the Law. And all gold & silver in the sense of the law is fine gold & fine silver if it be of the same fineness wth the Assay-piece. And because the Assayer works more exactly to a rule then the Refiner, & makes better dispatch, the Assay is made the standing universal Rule of valuing gold & silver in all nations in point of fineness, & the Law in ordeining that standard Gold shall be 22 carats fine & standard silver 11 ounces fine two penny weight fine, means by the Assay.
The assays of gold ought to be made with two waters & no more, this being the constant practise of assaying; & the waters ought to be of an|th||e| ordinary\usual/ strength (the second water stronger then the first) & to work the usual time & in the usual heat, & the assay piece ought to be hammered to the usual thinness that the Assays may be uniform. And the assays of silver ought to be made with a due proportion of lead in a due & eaven heat, & as soon as the lead is blown off & the silver looks bright & glittering, the silver must begin to cool without roasting it, & it must cool slowly that it do not spring. But in refining gold & silver in great quantities these niceties are not observed.
Refiners find it difficult to refine gold to the degree of 24 carats. They seldome make it above 23 carats 3 grains & 3 quarters fine of a grain fine, & by fine gold generally understand gold of this degree of fineness. And if gold at any time prove finer upon the Assay, Assayers out of prejudice do not report it finer. And thence it comes to pass that the Goldsmiths are generally of opinion that Gold cannot be made above 24 carats fine. But if when they have watered their granulated gold once or twice with Aqua fortis, they should dulcify it & grind it very fine as painters do their colours, & then water it once or twice more with double Aqua fortis in the same degree of heat as before & keep it longer in the water then before stirring it now & then with a wooden stick to make the gold mix wth fresh water: the gold would become finer then before by the Assay, & by conse{illeg}|qu|ence finer then four & twenty carats. Chymists also tell us that Gold may be made finer by Antimony then by Aqua fortis & by consequence then by the Assay; & Gold refined by Antimony is of a better colour then Gold refined by Aqua fortis, & by reason of its fineness will go much further in gilding, as I have heard. But the Refiners of this city know not how to refine gold by Antimony. And so silver also by being tested wth more lead & roasted becomes finer then by the common way of assaying, but not {illeg}|a| half-penny weight finer.
If Refiners should work perfectly in the same manner with Assayers that is, if they should mix gold with silver in the same proportion & drive it off the test with the same proportion of lead & ha{illeg}|m|mer it to the same thinness & water it with waters of the same strength in the same degree of heat during the same length of time, their gold would become just 24 carats fine. And by imitating the Assayer their silver would become twelve ounces fine. But they work not with so much curiosity & exactness. Their fine gold & fine silver must be assayed to know the just degree of fineness.
The standard Trial pieces re made by the assay, & will a{illeg}|l|ways agree with the assay if they be rightly made. But if a competent number of assays of the Trial piece agree with one another with{illeg}|o|ut any material difference, & at a medium are standard, the Trial piece is standar{d.}
Assays are liable to errors, but the errors are generally very small & seldome exceed a quarter of a grain in gold & an halfpenny weight in silver. And by reason of these little errors the Assayer in single Assays makes his report|s| to no less parts then a quarter of a grain in gold & a half penny weight in silver. But if two or more Assays be made of the same piece of gold or of the same piece of silver, & the assays {illeg}|a|gree without any considerable difference, & a medium be taken between them: the fineness of the gold may be {illeg}|d|etermined to less then half a quarter of a grain in gold & \& the fineness of the silver to {be}|le|ss then an/ half a halfpenny weight|.| in silver. |And| T|t|his is the exactest way of assaying hitherto in use
The standard Trial pieces are made by the Assay. First the Iury procures gold & silver of \refined by/ the Refiner, & assays them to see if they be standard of a just degree of fineness, that is, the gold just 24 carats fine & the silver just 12 ounces fine. Then they melt this gold & silver severally with allay in due proportion, & stir them well together in fusion several times to mix them \very/ well, & pour them off before the allay evaporates, & assay them several times to see if they be standard, taking assays fr{illeg}|o|m several places to see if the mixture be uniform. They must agree therefore with the assay as exactly as is possible least there be two standards, one by the Assay-weights the other by the Trial-piece
The trial of the moneys in the Pix is to be performed after the most just manner that can be made by fire by water by touch or by weight or by all or by any of them, as is exprest in the Indenture of |th|{a}|e| Mint. If the Trial piece be exactly made, the trial thereby is the most expedite & the least liable to errors. But a Trial piece may happen to be erroneus, & then the other ways of assaying, as they are lawfull so they may be also usefull. For the Ass{illeg}|a|y by the Assay-weights exactly made will discover the error of the Trial piece if their {sic} be any & how great that error is; & the Assay by the touch being very easy may be also used to see how it agrees with the other Assays, but it is less exact & not to be depended upon alone.
The present case
At the last trial of the Pix the Iury by the Assay found that the money was standard full & the Triall piece a quarter of a grain better then the money, & the Iury in their Veredict that the money was {a} quarter of a grain worse then standard by the stand Trial piece. The
Veredict imployed that the Trial-piece was standard & the money a quarter of a grain wors then standard, tho the Iury found by the Trial that the money was standard & the Trial piece a quarter of a grain better then standard. By my assays this Trial piece is five twelft parts of a grain better then standard, that of 1688 is the sixt part of a grain better, that of 1660 is standard
Quære
If upon any triall of the Pix the Trial piece prove better or worse then standard, are not the Iury to ascertain & report the error, & may not the Master of the Mint by an Order of Council allow for that error in coyning the money by that Trial piece for the future without putting the Government to the trouble & charge of making a new one? Or must a new Trial-piece be made; or the money continue to be coyned & tried by a false Trial piece without inquiring into the error; & so the Company of Goldsmiths have it in their power without controll, to alter the standard as often as they are to make a new standard Triall-piece?
