Joaquín Velázquez de León (1732-1786), astronomer of New Spain
A Mexican-born astronomer who taught himself mathematics after finding neither professor nor books nor instruments at his college, learned indigenous languages and the reading of Aztec glyphs from an Indian teacher before he read Newton, built his own telescopes, corrected an error of longitude that had misplaced California for centuries, observed the transit of Venus of 1769 from a plank observatory, and drew the plans that created the mining tribunal and school of Mexico.
Why this wins its question: Velázquez de León appears in English almost only as a name attached to the founding of the Colegio de Minería, or not at all; the transit of Venus of 1769 in California is told as the story of the Abbé Chappe, who died there. This object puts the Mexican observer back in the frame with what the text actually says — the plank observatory at Santa Ana, the eclipse prediction the French astronomer disbelieved, the longitude error that had misplaced California for centuries, the telescopes he built because none could be bought, the indigenous teacher who taught him Nahuatl and glyphs before he read Newton — and refuses to launder the frame: the college that held no books, the visita that ended in a new impost, the tribunal for silver, and one admiring source carrying all of it.
Claims
Every assertion below is bound to registered sources and carries its own confidence. Weight them; do not treat the page as uniformly authoritative.
Humboldt calls him "the most remarkable geometrician produced by New Spain since the time of Siguenza" — printing the name as Don Joacquin Velasquez Cardenas y Leon — and says that all his astronomical and geodesical labours "bear the stamp of the greatest precision". He gives his birth as 21 July 1732, in the interior of the country, at the farm of Santiago Acebedocla near the Indian village of Tizicapan, and credits him with "the merit, we may say, of forming himself".
His education began with an indigenous teacher. At the age of four he communicated smallpox to his father, who died of it; an uncle, parish priest of Xaltocan, took charge of him and placed him under the instruction of "an Indian of the name of Manuel Asentzio, a man of great natural strength of mind, and well versed in the knowledge of the Mexican history and mythology", and at Xaltocan Velázquez learned several Indian languages and the use of the hieroglyphical writings of the Aztecs.
The formal institutions of the capital gave him almost nothing. Placed at Mexico in the Tridentine college, "he found neither professor nor books nor instruments", and fortified himself as best he could in mathematics and the ancient languages until a lucky accident threw the works of Newton and Bacon into his hands. The English translator attaches a footnote to that sentence remarking that the professors of the university are "not behind those of some others in the praiseworthy custom of considering their chairs as sinecures" — the reproach is printed on the same page as the praise.
Unable to buy an instrument anywhere in Mexico, he and his friend Guadalajara, later professor of mathematics at the Academy of Painting, built telescopes and quadrants for themselves; he practised as an advocate, an occupation the text calls "much more lucrative than that of looking at the stars", and laid out what he earned by it on instruments purchased in England.
Named professor in the university, he accompanied the visitador José de Gálvez on his journey to Sonora and was then sent on a commission to California, where he made a great number of astronomical observations and first established that through an enormous error of longitude the maps had for centuries placed that part of the new continent several degrees farther west than it really is.
He built himself an observatory of mimosa planks at Santa Ana, and having already fixed the position of that Indian village he told the Abbé Chappe d'Auteroche, newly arrived in California, that the moon's eclipse of 18 June 1769 would be visible there; the French astronomer doubted it until the eclipse took place. Velázquez then observed the transit of Venus of 3 June 1769 by himself and communicated his result the same morning to Chappe and to the Spanish astronomers Vicente Doz and Salvador de Medina, and the agreement between his observation and Chappe's own surprised the French traveller, who was, in Humboldt's words, "no doubt astonished to meet in California with a Mexican, who, without belonging to any academy, and without having ever left New Spain, was able to observe as well as the academicians".
In 1773 he executed the great geodesic undertaking whose results Humboldt used in his own geographical introduction, and which the same passage connects with the question of draining the lakes of the valley of Mexico.
The service Humboldt rates highest is institutional rather than observational: "the most essential service which this indefatigable man rendered to his country was the establishment of the Tribunal and the School of Mines, the plans for which he presented to the court". He died on 6 March 1786 while first director-general of the Tribunal de Minería, holding the title of alcalde del corte honorario.
The institutions he founded existed to serve silver extraction, and the patron he travelled with is described by his own admirer in cool terms: a footnote on the same page says that the journeys of the visitadores generally had no effect beyond counterbalancing for a time the power of the viceroys and the audiencias, receiving an infinity of memoirs and petitions, and "signalizing their stay by the introduction of some new impost", the people awaiting their arrival with the same impatience they afterwards showed for their departure. The career and the extractive purpose are not separable.
Every statement above rests on one witness, and not an eyewitness: Humboldt was in New Spain in 1803 and 1804, seventeen years after Velázquez died, and writes as an advocate of colonial scientific talent against European condescension. The indigenous teacher who formed him, Manuel Asentzio, is named once and never again, and nothing further about him is recorded here. Confidences on this object are set accordingly, and a documentary life from the mining tribunal's own archive would raise them.