The assay ordinances of the Indies: one standard of fineness, instruments and marking across a continent
Libro IIII título XXII of the Recopilación prints the ordinances of the ensayadores mayores of Peru: assay by fire and cupel only, never by colour or hammer-blow; a register of everyone examined; standard weights, a standard furnace and checked balances; the fineness in dineros and grains with new punches; and every bar stamped with the assayer's name, year and place. The purpose was the royal fifth, and unmarked silver was a crime for Indian and Spaniard alike.
Why this wins its question: The standard account of American silver goes from the mine to the mint to Europe and never names the assayer, so the question of how a bar leaving Potosí could be trusted anywhere is usually answered by the word "quality control" or not at all. This object answers it from the code: fire and cupel only, with judgement by colour or hammer-blow expressly forbidden; central non-delegable examination and a dated register of who was licensed; a standard dineral, a standard iron furnace and a checked balance issued to every assayer so that assays would agree; the fineness rewritten from maravedís into dineros and grains with new punches down to the form "XI.D.XVIII. G. m."; the assayer's name, the year and the mine or camp struck on every bar on pain of losing his office; and a registered maker's mark for every silversmith, proclaimed town by town. It then puts the other half on the record in the same voice: the fifth was the reason, unmarked plate in a private house was an offence for Indian and Spaniard alike, some of the offices had been sold, and the printing shows no evidence at all that any of it was obeyed.
Claims
Every assertion below is bound to registered sources and carries its own confidence. Weight them; do not treat the page as uniformly authoritative.
The subject has its own título in the code. Libro IIII, título XXII of the Recopilación de leyes de los reynos de las Indias is headed "Del ensaye, y fundicion del oro y plata", and what it prints is a series of numbered capítulos — the ordinances of the ensayadores mayores — running at least from capítulo 4 to capítulo 25. Título XXIII, "De las casas de moneda, y sus oficiales", begins immediately after it.
Only one test was allowed, and the alternatives are named and banned. Capítulo 7 orders the assayers of bars residing in smelting houses or mining camps to assay every bar of silver and every tejo of gold that leaves them, "cada barra, ó tejo de por sí", and forbids anyone to apply the punches of the fineness, his señal or his mark "ni valerse para esto del color de la plata, ú oro, golpe de martillo, ni de otra forma, mas que el ensaye por fuego, y copella" — on pain of loss of office and of all his goods, a third of the value to the denouncer.
Practitioners were licensed centrally and the licence could not be delegated. Capítulo 5 acknowledges that the distance from the Ciudad de los Reyes, where the ensayadores mayores reside, to the smelters and in particular to Potosí and its mint might seem to make it hard for every assayer to come and be examined, and then orders that "sin embargo de qualquier distancia todos se exâminen por los Ensayadores mayores, sin que esta facultad la puedan delegar, ni cometer á otra ninguna persona, y que sin ser exâminado, y aprobado ningun Ensayador sea admitido á usar este oficio, y exercicio en ninguna parte". A book was to be kept of everyone examined and approved, "para que en todo tiempo conste quales están, ó no exâminados, y desde que dia".
The instruments were standardised as deliberately as the method, and the reason given is public harm. Capítulo 8 orders the ensayadores mayores to issue each man they examine the dineral of silver and of gold with its diminution in grains and half-grains — the silver dineral of a tomín and a half of the marco, the gold dineral of half a tomín of the tomines of gold — together with an iron furnace of the size and form used in Castile under the ordinances of 1588, and to check the balances the assayer carries, "para que siendo todos conformes en el peso, é instrumentos, lo sean tambien los ensayes, y no haya la diferencia, que hasta ahora se ha experimentado en tanto daño del bien público". Capítulo 9 adds the assayer's own box and balance with its guindaleta, also to be examined, "por consistir en ello el mayor acierto, y mejor afinacion de los ensayes".
Every bar was made traceable to a person, a year and a place. Capítulo 11 requires each assayer, after assaying, to mark the bar of silver or tejo of gold with his mark or señal bearing his name, "poniéndole claro, y distinto de modo que se sepa, y conozca quien lo ensayó, y tambien el año, con el nombre del lugar, mina, ó asiento en que se ensayare: pena de que si algo de esto faltare, pierda el oficio". A mark struck but illegible drew an arbitrary penalty scaled to the number of bars, on the certificate of the scribe of the royal treasury, the assayer's name being "siempre ... la principal, para que así se tenga entera noticia de los Ensayadores de todas".
The notation itself was reformed because the old one had produced errors. Capítulo 12 records that the assayers of the provinces of Peru had been writing the fineness of silver bars in maravedís, that "grandes yerros, é inconvenientes" had been recognised in this and that some had tried to defend or minimise them, and that fineness is not assayed in maravedís but in dineros and grains; it therefore orders the fineness to be entered in dineros, grains and half-grains, and each assayer to have new punches cut with Castilian numerals, a D for the dinero, a G for the grain and a small m for the half, so that a bar reads in the form "XI.D.XVIII. G. m."
The standard of fineness itself is stated and is the coinage standard. Capítulo 10 gives it as silver of eleven dineros and four grains, "que es la ley de que se labran los reales, conforme á las leyes de estos nuestros Reynos de Castilla y de las Indias", and prescribes the lead to be added in assay, five tomines and downward in proportion, three grains of lead for each grain by which the silver falls below fineness. Capítulo 23 applies the same figure to finished work: silversmiths, wire-drawers and gold-beaters are to be visited and anything below eleven dineros four grains of silver, or gold below twenty-two carats, is to be broken up, "sin embargo de qualquier apelacion".
The consumer-facing end of the system is a registered maker's mark. Capítulo 25 orders that every silversmith working pieces of gold or silver "tenga su marca particular, la qual manifieste ante la Justicia, ó Escribano de Cabildo de el Lugar adonde residiere", and strike it on the pieces he makes, so that if the metal is found below fineness the silversmith can be proceeded against; the chapter was to be proclaimed by the ensayadores mayores in every city, town and place they visited, under special order of the viceroy. Capítulo 24 reserves to them the examination of the marcadores de plata and tocadores de oro wherever there were silversmiths' quarters, "sin embargo de qualquier costumbre, ó privilegio de Ciudad, Villa, ó Lugar".
Penalties on the assayer escalate, and the office of the ensayadores mayores is defined as detection. Capítulo 14 sets an arbitrary penalty for a variation of two or three grains, and beyond that double the value of the bars for the first offence, half the offender's goods for the second, and for the third all his goods and the office itself, the same to be kept in the assays of gold by carats. Capítulo 15 states that the offices of ensayador mayor "se han criado para que por ellos se puedan saber, averiguar y castigar los yerros y fraudes, que hubiere en los ensayes de la plata y oro", their principal exercise being to re-assay the bars, royal and private, that came down from all the smelters.
The system's purpose was fiscal, and the code says so without embarrassment. Capítulo 13 fixes the reduction of assayed silver to maravedís expressly "para cobrar nuestros quintos Reales, y hacer las cuentas necesarias á las contrataciones, comercios, pagas, cobranzas", and capítulo 12 ends by directing the officials of the royal treasury to collect the fifths on that count. Bars not assayed in the prescribed form were not to be admitted "en los quintos Reales, ni en nuestras caxas, comercio, ni en otra ninguna parte", on pain of forfeiture of the bar and of the assayer's office. The accuracy of the assay and the yield of the royal fifth were the same interest.
The same regime bore on private people, including Indians. Libro VIII, ley xxxxvij, dated Valladolid 28 October 1559 and El Pardo 8 July 1578, forbids all residents and inhabitants of the Indies, "así Indios, como Españoles", to have in their houses any wrought silver or gold, jewels, pearls or stones that are not quinted and marked and the duties paid, on pain of losing them; and "el Platero, Indio, ó Español, ú otra persona, que lo tuviere para labrar, sin estar quintado, y marcado, incurra en perdimiento de todos sus bienes". The traceability that protected a buyer also made an unmarked household object contraband.
The code also records the weakness of its own design. Capítulo 6 declares that some offices of ensayadores menores had been sold or made perpetual in persons entitled to serve them by deputies, and rules that the proprietors remain bound "con la propiedad de los oficios á las faltas, yerros, y penas en que los Tenientes incurrieren, como Ensayadores, por sus ignorancias, negligencias, ó fraudes" — an admission that the assay of American silver was in part in the hands of purchased offices worked by substitutes. The code answers it with liability, not with abolition.
What is read here is the statute and nothing else. These capítulos are addressed to the provinces of Peru and to the assayers under the ensayadores mayores resident at Lima; no equivalent for New Spain was read for this object, and the printing gives no counts of assayers examined, no visitation records, no prosecutions and no surviving marks. Whether bars were in fact stamped as ordered, whether the dinerales and furnaces were in fact distributed, and what any of it cost the workers of Potosí are questions this source does not answer and this object does not assert.