Holograph draft of <ref target="/catalogue/record/MINT00173">MINT00173</ref> (Mint 19/1/109) Isaac Newton c. 1,366 words The Newton Project Oxford 2017 Newton Project, University of Oxford

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 After 21 August 1710, c. 1,366 words. Memorandum by Newton: 'Of the assaying of Gold and Silver, the making of indented Triall-pieces and trying the moneys in the Pix' [MINT 19/1/109] MINT 19/1/288-9, National Archives, Kew, Richmond, Surrey, UK UKSurreyKew, RichmondNational Archives MINT 19/1/288-9 After 21 August 1710 England English Holograph MintPyx Trials and Analyses of British Coinage Catalogue information compiled by Rob Iliffe, Peter Spargo & John Young Catalogue exported to teiHeader by Michael Hawkins Transcribed by Will Scott

Of the assaying of Gold & silver, the making of indented Triall pieces, & trying the moneys in the Pix.

1 Of 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) ithe two carats better then standard orgold 24 carats fine if it be gold& the sitolver 12 ounces fine. if it be silver. And this is fine gold & fine silver in the sense of the law. And all gold & silver is fine gold & fine silver in the sense of the law if it be of the same fineness with 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 two penny weight fine, means by the assay.

The assays of Gold ought to be made wthwith two waters & no more, this being the constant practise of assaying, & the waters ought to be of the 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 usuall thinness that the Assays may be uniform. And the assays of silver ought to be made wthwith a due proportion of Lead in a due & eaven heat, & as soon as the silverLead 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 to be observed

Assays are liable to errors, but the errors are generally very small & seldome exceed a quarter of a grain in gold or an halfpenny weight in silver. And by reason of these little errors, the Assayer in single Assays makes his report to no less then a quarter of a grain in gold & an 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 agree without any considerable difference & a medium be taken between them: the fineness of the gold may be determined to less then half a quarter of a grain & the fineness of the silver to less then half an half penny weight. And this is the exactest way of assaying hitherto in use.

2 Of making the Triall-pieces.

The standard Triall-pieces are made by the Assay. First thea Iury of workmen summoned & sworn by order of Council procures gold & silver refined by the Refiner; & assays them to see if they be 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 & stirr them well together in fusion severall times to mix them very well, & pour them off before the Allay evaporates, & then assay them severall times to see if they be standard, taking assays from several places to see if the mixture be uniform. It 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.

Refiners

Refiners find it difficult to refine gold to the degree of 24 carats. They seldome make it above 23 carats 3 grains 3 quarters 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 Goldsmiths are generally of opinion that gold cannot be above 24 carats fine, not knowing that there are ways of making it finer then by the assay. Thence also it may have sometimes happened that at the making of new Trial-pieces the Assayer may have reported the fine gold not so fine as it really was, & by that means the Trial piece may have been made too fine. And if the fine gold was by 23car. 3gr. 3qters fine, the Trial piece may have been made too coarse. And there are other ways of erring as by assaying after any unusual manner, or by scattering any part of the allay or of the gold &or suffering a sensible quantity of the allay to evaporate or not mixing the gold with the allay very well, or using a faulty crucible.

3 Of trying the Pix.

1 The tryall of the moneys in the Pix is to be performed by a Iury of Assayers be in the presence of yethe Warden Master & Comptroller of yethe Mint 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 the Mint The Pix is opened & the Iury sworn before her MajtyMajesty or such of her Council as her MatyLordship shall the trial appoint. If the Triall pieces be exactly made the trial thereby is the most expedite & the least liable to errors. But a Trial piece may happen to be erroneusous & then the other ways of assaying, as they are lawfull, so also they may be usefull. For the Assay by the Assay weights exactly performed will discover the error of the Trial piece if there be any, & how great that error is, & the Assay by the touch may be also used to see how it agrees with the other Assays, but it is be less exact & not to be depended upon alone.

3 If at any time the Trial-piece doth not agree wthwith the Assay, either the error must be reported by the Iury or it must not be reported. by the Iury. If it be reported, either the Master of the Mint must be authorized to allow for the error in coining the money by that Trial piece for the future or a new Trial piece must be made. If it is must not be reported the Master must go on to coin the money by an erroneous Trial piece, & the Goldsmiths must have it in their power to alter the standard without controll as often as they are to make a new Trial-piece, & to make a new standard instead of making a new Trial piece agreeable to the standard established by law.

2 At the last trial of the Pix the gold money was standard full by the Assay, & the Trial piece a quarter of a grain better then the money, & the Iury in their Veredict represented the money a quarter of a grain worse then standard by by the Trial piece. standard.. This Trial piece was made (I think) A.C. 1707 it was made (I think) without the Queens order A.C. 1707, & by my Assays very carefully made is five twelfts of a grain better then standard, that of 1688 was made by order of K.King IJames II is a sixt part of a grain better then standard, & that of 1660 made by order of K.King Charles II is standard.

Quære 1. If upon trying the Pix, the Trial-piece at any time doth not agree with the Assay, whether are not the Iury to report the error?

Quære 2. If any other doubt arise about the manner of the Report or Veredict, whether are not the Iury to make a special Report of the matter of fact, & leave it to the Queen & Council to make a judgment thereupon?