Diego López de Arenas, Breve compendio de la carpintería de lo blanco (Seville, 1727 impression)
A working Seville master carpenter put the geometry of the Andalusian timber roof into print — thirty-two chapters of template-squares, muqarnas clusters, land valuation, artillery calibre and sundials, written because disputes over measurement filled the courts. Its last table gives the pole altitudes of Mexico, Havana, Veracruz, Oaxaca, Guatemala and a dozen more American places, and the author says why: the fleets carried carpenters, masons and gunners who might need them.
Why this wins its question: English writing on the Spanish lace-work timber roof is a paragraph in architectural surveys that names López de Arenas and moves on, without a line from him. This object works from the printing itself: the author's own account of why he wrote it — disputes over measurement filling the courts — his deliberate refusal to replace the shop's words with the geometers', the eighteen cartabones, the muqarnas chapter with its Arabic vocabulary, the Tartaglia problem answered by construction under the maxim that the compass settles what the pen cannot, and the closing table of American latitudes with the sentence that explains it. The last is the part nothing else in reach states at all: a Seville carpenter's manual carried the pole altitude of Mexico and Havana because the fleets carried carpenters. The object also says, in its own last claim, what the book cannot prove about its own diffusion.
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 book was written by a practitioner, not a theorist. Its title page names the author "Diego Lopez de Arenas, Maestro del dicho oficio, y Alcalde Alarife en el; natural de la Villa de Marchena, y vecino de la Ciudad de Sevilla" — a master of the trade who also held the municipal office of building surveyor.
The stated motive is litigation, not connoisseurship. In the prologue the author says that in his terms as Examinador and Alcalde Alarife he had found that the matter of measurements and the rules of carpentry were "no esta tan conocida, y apurada, como es necessario", and the masters and journeymen not "tan conformes entre si para el executarla, como conviene, de que se originan pleitos, que siempre hai en todos los Tribunales en materia de casas". He wrote the compendium so that masters could read in brief what they had learned in bigger books and so that apprentices and journeymen might reach mastery "con menor trabajo, q otros", with the terms of geometry set out so as not to obstruct them.
The method is construction rather than calculation, and the book says so. Chapter II opens by defining the three lines of every triangle or cartabón as they are named "geometricamente" — Cathecus, basis and hypotenusa — and then states that the author renames the hypotenusa as basis "por no innovar, ni mudar de estilo", keeping the shop's own vocabulary in place of the geometers'. The chapters that follow work entirely by dividing the width of the house into twelve parts, striking a semicircle called the Cambija, and cutting template-squares from it; chapter VI is given over to "todos los diez y ocho cartabones, con que se cortan las armaduras, y los lazos, y boquillas".
The craft it records is the Andalusi one, and its technical vocabulary is Arabic. Chapter XVIII is headed "como haras los racimos de mocarabes, y amedinados" — the pendant muqarnas cluster — and works from the octave of the almizate, the flat central field of the roof, after deducting the thickness of the albernica; other chapters turn on limas moamares and arrocabes. The book therefore transmits in Castilian print a body of geometry whose terms are those of the Islamic carpentry of al-Andalus.
What the manual covers is far wider than roofs, and maps what a Spanish master builder was expected to know. Its table of thirty-two chapters runs from the cartabones and the armaduras to the valuation of building plots and their square feet (chapter XXV), the measurement of the half-orange dome and the level (XXVI), the calibre and first weights of iron and stone shot (XXVII), the line of a tripled cubic body (XXVIII), the graduated quadrant for making clocks (XXIX), horizontal, vertical and declining sundials (XXX and XXXI), and the pole altitudes of cities, towns and places (XXXII). A discourse in dialogue form and a chapter of "algunas reglas de Geometria" sit between them.
The book reaches Italian mathematics and answers it with a compass. Its title page promises "la conclusion de la regla de Nicolas Tartaglia", and chapter XXVIII delivers it: how to draw the line of a "figura tripla" for cubic bodies, and not for plane surfaces, and apply it to the diameter of an artillery ball three times the weight of another. The margin of that page carries the maxim on which the whole book rests: "El compàs absuelve, lo que la pluma no puede".
The manual's last table is American. "Tabla de las Ciudades, Villas, y Lugares de España, Islas de Canaria, y Cabo Verde, Islas, y Lugares de las Indias Occidentales, por su abecedario" gives degrees of pole altitude in three columns; the third is headed "Islas, y Lugares de las Indias Occidentales" and lists Santo Domingo, Puerto-Rico, San German, Xamaica, Cuba, La Habana, Matanzas, La Veracruz, Mexico, Guazacalco, Guaxaca, Goatemala, Nicaragua, Cubagua, La Margarita, Guadalupe, Bahama, Puerto de plata, Puerto-Real, Ayaguana and La deseada.
The author states his reason for printing it, and it is the fleets. On the page facing the table he writes: "He puesto esta tabla destas Islas, y Lugares Occidentales, porque en la Carrera de las Indias en Flotas, y Armadas hai muchos curiosos Artilleros, Carpinteros, y Albañiles, y conociendo yo la aficion, que todos tienen al compàs, y que se les podria ofrecer alguna ocasion en essas partes, les quise servir en esto". A sundial cannot be laid out without the latitude of the place, so the table is what makes the sundial chapters usable in America.
The figures in that table are rough, and the object does not present them as survey data. They are whole degrees only, and several are wide of the mark — Guatemala is given as 13 against a true latitude near 14.6, Mexico as 20 against about 19.4, Oaxaca as 18 against about 17.1. They are good enough to set a gnomon and no better, which is what the chapters they serve require.
This printing is a reprint of an earlier book whose date it does not give. The title page describes it as "corregido, y mejorado en esta ultima impression" with an added Suplemento of two treatises — one continuing the sundials, with lunar dials, and one "una Practica facil de las Visitas, y Aprecios ... de mucha utilidad para los Maestros, y Alarifes" — and the two licences bound in front of it, of 29 and 30 July 1727, both grant leave for the "reimpression" of the book. Nothing read here dates the first edition, and this object does not assert one.
What the source cannot show is what the book did. No copy is traced here to any American workshop, no American building is attributed to it, and the author's sentence about the fleets records an intention, not a use. The claim that the carpintería de lo blanco crossed the Atlantic rests here on the printed intention and on nothing else; the surviving artesonado ceilings of Spanish America are not evidence read for this object. Nor is anything here evidence about the wages, terms or standing of the carpenters and masons who sailed with the fleets.