Description

By a Maker of Rock-Crystal Lenses, French, late 1830’s, signed “Rossin, nev. et succ. de Chauchoix.” Opening from 3-1/2″ to 6-3/4″ (9 – 17 cm), this large “monocular” is made of gilt brass with two drawtubes, the bell-shaped main tube bound in four floral-filled panels alternating red and brown. The singlet objective is a full 2-1/4″ in diameter, and with the thick bi-concave eye lens gives bright erect images. Focusing is by helical thread to the first drawtube. Condition is fine noting hairline cracks to the panels.

Rossin was Cauchoix’s nephew, working with him and taking over the workshop in 1836. Robert Aglaé Cauchoix (1776 – 1845) became famous as lens maker, producing lenses of rock crystal, publishing on them in 1828. His achromatic telescope received a gold medal, and he supplied telescopes to Cambridge Observatory. Rossin himself is known for a lorgnette with crystal lenses (see Marcelin).