La Filotecnica Rolling Parallel Rule
date: label: date made
content: ca 1870
name: label: maker
content: Officina Filotecnica
notes: label: Description
content: 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 £ £ £.
label: Description
content: 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.
label: Description
content: References: Paolo Brenni, "Italian Scientific Instrument Makers of the Nineteenth Century and Their Instruments," in <i>Nineteenth-Century Instruments and Their Makers</i>, 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, <i>The Nautical Sextant</i>, http://sextantbook.com/2010/10/05/a-fine-sextant-by-filotecnica-salmoirhagi-of-milan/.
label: Location
content: Currently not on view
place: label: place made
content: Italy: Lombardy, Milan
topic: label: Subject
content: Mathematics
label: Subject
content: Drafting, Engineering
setName: label: See more items in
content: Medicine and Science: Mathematics
label: See more items in
content: Science & Mathematics
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content: Parallel Rules
creditLine: label: Credit Line
content: Gift of Ursula N. Forbes
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1986.0316.04
label: catalog number
content: 1986.0316.04
label: accession number
content: 1986.0316
objectType: label: Object Name
content: parallel rule in case
label: Object Name
content: parallel rule
physicalDescription: label: Physical Description
content: german silver (overall material)
label: Physical Description
content: wood (overall material)
label: Physical Description
content: fabric (overall material)
label: Measurements
content: overall: 3.8 cm x 27.5 cm x 7.5 cm; 1 1/2 in x 10 13/16 in x 2 15/16 in