La Filotecnica Rolling Parallel Rule

This ten-inch German silver instrument has two rollers connected by a shaft. Both ends have knobs to hold while rolling the parallel rule. Both long edges have centimeter scales, divided to millimeters and numbered by ones from 0 to 24. The instrument is marked: "LA FILOTECNICA" MILANO. A wooden case is lined with dark blue velvet and has ornate brass clasps. The bottom of the case is marked in red pencil: S_301 £ £ £.

Ignasio Porro (1801–1875) established La Filotecnica in Milan in 1865 to train students to make optical and mathematical instruments. Between 1870 and 1877, one of his apprentices, Angelo Salmoiraghi (1848–1939), purchased the firm and put more emphasis on manufacturing. By 1906 the company was renamed Filotecnica Salmoiraghi.

References: Paolo Brenni, "Italian Scientific Instrument Makers of the Nineteenth Century and Their Instruments," in Nineteenth-Century Instruments and Their Makers, ed. P. R. de Clercq (Amsterdam: Rodopi B.V., 1985), 196–198; Bill Morris, "A Fine Sextant by Filotecnica Salmoiraghi of Milan," October 5, 2010, The Nautical Sextant, http://sextantbook.com/2010/10/05/a-fine-sextant-by-filotecnica-salmoirhagi-of-milan/.

Currently not on view