Catalogue Entry: MINT00173

Memorandum by Newton: 'Of the assaying of Gold and Silver, the making of indented Triall-pieces and trying the moneys in the Pix'.

Author: Isaac Newton

Source: MINT 19/1/109, National Archives, Kew, Richmond, Surrey, UK

[Normalized Text] [Diplomatic Text]


Stresses the importance of observing consistent methods in these operations, and describes procedures for ensuring maximum accuracy. It can happen that trial plates are made finer than standard gold coin and consequently the coin is found deficient, as happened at the last trial [21 August 1710, though the deficiency noted did not exceed the remedy and the coin was passed]. The master must have authority to compensate for faulty trial plates, either by having new ones made or by adjusting the refinement of the coinage accordingly. The trial plates of 1707 and 1688 are both above standard: that of 1660 is standard.

Three (rhetorical) queries as to whether the pyx jury should (a) report any discrepancy between the assay and the trial piece; (b) submit disputed results to the deliberation of the Queen and Council, and (c) undertake a second test in the event of dubious results, especially if asked to do so by the Mint officers.

On reverse: a mathematical problem.


[See Mint Annual Report (1873), 39 (on the true fineness of the plates complained of by Newton); also Craig, NATM, 77-8 and Westfall, 610.]

Printed in NC, 5: 84-90 with additions from the drafts listed at MINT00174 below.

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Professor Rob Iliffe
Director, AHRC Newton Papers Project

Scott Mandelbrote,
Fellow & Perne librarian, Peterhouse, Cambridge

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