**One of the rarest of Mexican imprints relating to mining, the environment, and the state of indigenous peoples at the beginning of the 19th century**

* Tratado de la amalgamacion de Mexico*

Mexico: Impr. de d. Mariano de Zuniga y Ontiveros, 1805.

First Edition. Leather Binding. Very Good. 16mo - over 5¾" - 6¾"

Humboldt's description of the patio mining process is based upon this work. No copies at auction in a century. Friedrich Sonneschmidt was a German mining engineer sent by the Spanish crown to Mexico to examine the state of silver processing and refining. He examined the mines and processing facilities, comparing the efficiency of the patio amalgation process versus the Born barrel process, with the goal of decreasing the use of expensive mercury. As Godoy concludes (in "A German minerologist visits Peru") "Sonneschmidt had to admit - in his famed treatise on amalgamation - that "with ten years of work I have been unable to introduce, either Born's refining process or any other method preferable to that of the patio." and ultimately in this study advocated the changes in the patio process to increase efficiency", abadoning his advocacy of use of the the Born process in Mexico. As the the patio process involved foot stamping of mercury and ore by indigenous workers, Sonneschmidt failure had serious consequences.

Sabin 86967, recording only a single copy.

Worldcat records only 4 copies (only one on the US at Yale, none in Mexico).

[8] + 264pp. Half brown period leather over marbled boards, with gilt title, and rules on spine. A nice clean complete copy in a period binding, the text is exceptionally clean.