Prism Monocular
date: label: date made
content: ca 1862
name: label: maker
content: Hofmann, Jean Georges
notes: label: Description
content: The inscriptions on the eye end of this small optical instrument read “443” and “J. G. Hofmann / rue de Buci 3 / Paris.” That on the objective end reads “J. G. HOFMANN / PARIS.” Inside is a prism assembly that shortened the length of the instrument but maintained its longer focal length. Both prisms are marked, in pencil, “J.G.H.” The objective lens is marked, in pencil, “J.G. Hofmann à Paris 1862.”
label: Description
content: Ignazio Porro (1801-1875) was an Italian engineer who moved to Paris in 1842. In 1847 he established an Institut Technomatique et Optique that manufactured optical instruments for surveying work. He designed the prism assembly, as found in this monocular and in later binoculars, around 1850. He returned to Italy around 1861.
label: Description
content: Jean Georges Hofmann was a German optician who worked with Porro in Paris. He would later design and make such instruments as spectroscopes and saccharimeters.
label: Location
content: Currently not on view
place: label: place made
content: France: Île-de-France, Paris
setName: label: See more items in
content: Medicine and Science: Physical Sciences
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content: Science & Mathematics
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content: Optics
creditLine: label: Credit Line
content: Ralph K. Dakin
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1986.0465.2
label: accession number
content: 1986.0465
label: catalog number
content: 1986.0465.2
objectType: label: Object Name
content: monocular
physicalDescription: label: Measurements
content: overall: 2 1/2 in x 1 7/8 in x 4 1/4 in; 6.35 cm x 4.7625 cm x 10.795 cm
label: Measurements
content: overall: 1 7/8 in x 2 7/16 in x 4 1/2 in; 4.7625 cm x 6.19125 cm x 11.43 cm