The family of Juan Vernacci y Retamal (? - ca.1810) was of Tuscan origin (from Florence, then Pisa). In 1780, already a guardiamarina, he worked under the command of Vicente Tofiño on the cartographic survey of the Spanish coasts. During the expedition he worked on astronomy and, particularly, on the cataloguing of stars. With Gutiérrez de la Concha he drew up the general charts of the coasts of Argentina. In 1792, as second-in-command of the schooner Mexicana, he participated in the second voyage to the northwest undertaken by the Malaspina Expedition. Subsequently he worked on the cartography of central America. In 1804 he was in Manila, on behalf of the Real Compañía de Filipinas.
For more information, see:
D. MANFREDI, "Un patrizio fiorentino nella Spedizione Malaspina: Giovanni Giuseppe Vernacci y Retamal," Rivista Araldica, LXXXVII (1989), n. 839, pp. 104-109.
Updated: June 15, 2018