M. d’Arcet, charged by the Commission of the Mint in Paris, to examine into the justice of the reclamations made by the French silversmiths against the public assays, ascertained that they were well founded; and that the results of cupellation gave for the alloys between 897 and 903 thousandths (the limits of their standard coin) an inferior standard, by from 4 to 5 thousandth parts, from the standard or title which should result from the absolute or actual alloy.
The mode of assay shows, in fact, that an ingot, experimentally composed of 900 thousandths of fine silver, and 100 thousandths of copper, appears, by cupellation, to be only, at the utmost, 896 or 897 thousandths; whereas fine silver, of 1000 thousandths, comes out nearly of its real standard. Consequently a director of the Mint, who should compound his alloy with fine silver, would be obliged to employ 903 or 904 thousandths, in order that, by the assay in the laboratory of the Mint, it should appear to have the standard of 900 thousandths. These 3 or 4 thousandths would be lost to him, since they would be disguised by the mode of assay, the definitive criterion of the quantity of silver, of which the government keeps count from the coiner of the money.
From experiments subsequently made by M. d’Arcet, it appears that silver assays always suffer a loss of the precious metal, which varies, however, with the standard of the alloy. It is 1 thousandth for fine silver,
| 4·3 | thousandths | for | silver | of | 900 | thousandths, |
| 4·9 | — | for | — | of | 800 | — |
| 4·2 | — | for | — | of | 500 | — |
and diminishes thereafter, progressively, till the alloy contains only 100 thousandths of silver, at which point the loss is only 0·4.
Assays requested by the Commission of the Paris Mint, from the assayers of the principal Royal Mints in Europe, to which the same alloys, synthetically compounded, were sent, afforded the results inscribed in the following table.
| Names of the Assayers. | Cities where they reside. | Standards found for the Mathematical Alloys. | |||||
|---|---|---|---|---|---|---|---|
| 950 mill. | 900 mill. | 800 mill. | |||||
| F. de Castenhole, Mint Assayer | Vienna | 946 | ·20 | 898 | ·40 | 795 | ·10 |
| A. R. Vervaëz, Ditto | Madrid | 944 | ·40 | 893 | ·70 | 789 | ·20 |
| D. M. Cabrera, Assayer in Spain | Ditto | 944 | ·40 | 893 | ·70 | 788 | ·60 |
| Assayer | Amsterdam | 947 | ·00 | 895 | ·00 | 795 | ·00 |
| Mr. Bingley, Assay Master | London | 946 | ·25 | 896 | ·25 | 794 | ·25 |
| Mr. Johnson, Assayer | Ditto | 933 | ·33 | 883 | ·50 | 783 | ·33 |
| Inspector of the Mint | Utrecht | 945 | ·00 | 896 | ·50 | 799 | ·00 |
| Assayer of the Mint | Naples | 945 | ·00 | 891 | ·00 | 787 | ·00 |
| Assayer of Trade | Ditto | 945 | ·00 | 891 | ·00 | 787 | ·00 |
| Assayer of the Mint | Hamburgh | 946 | ·13⁄72 | 897 | ·41⁄72 | 798 | ·44⁄72 |
| Ditto | Altona | 942 | ·1⁄4 | 894 | ·00 | 790 | |
These results, as well as those in still greater numbers, obtained from the ablest Parisian assayers, upon identical alloys of silver and copper, prove that the mode of assay applied to them brings out the standard too low; and further, that the quantity of silver masked or disguised, is not uniform for these different eminent assay masters. An alloy, for example, at the standard of 900 thousandths is judged at
| M. | |||
|---|---|---|---|
| the Mint of | Paris | to have a standard of | 895·6 |
| At that of | Vienna | — | 898·4 |
| — | Madrid | — | 893·7 |
| — | Naples | — | 891·0 |