The water engine of Potosí: the reservoirs and the ingenios de la ribera

Potosí gets rain three or four months a year, so its silver industry ran on stored water. Acosta's Seville imprint of 1590 counts the plant: seven gated reservoirs of about 1,700 varas round and three estados deep, feeding forty-eight water-driven stamp mills on the ribera, four at Tanacoñuño, twenty-two at Tarapaya and thirty horse mills. The mercury and the forced labour are here too, and so is the sediment core.