Surveyor's Compass

Description:

This compass, which was designed to measure horizontal and vertical angles on hilly ground or in mines, resembles the one that the American surveyor, Lucius Lyon, described in 1828. It also resembles the Hedley's dial, devised in 1850 by John Hedley, H. M. Inspector of Mines in England. This example consists of a gimbal mounted vernier compass, a vertical arc, a sighting telescope, and a hanging level. The variation arc and vernier mechanisms are located on the compass face, under glass and protected from harm. The vertical arc is solid, graduated to 30 minutes, and read by vernier to single minutes. The inscription reads "JAMES REED & CO. Pittsburg, Pa. No. 383."

James Reed (1792-1878) was listed in the Pittsburgh directories in 1847 as a watch maker and jeweller. He began trading as James Reed & Co. in 1850, and in 1852 advertised as "Manufacturers of theodolites, surveyors compasses, leveling & grading instruments, &c."

Ref: Lucius Lyon, "Observations on Surveying Instruments, and the means of remedying their imperfections," American Journal of Science 14 (1828): 268-275.

William Ford Stanley, Surveying and Levelling Instruments (London, 1901), pp. 311-319.

Maker: James Reed & Co.

Location: Currently not on view

Place Made: United States: Pennsylvania, Pittsburgh

See more items in: Medicine and Science: Physical Sciences, Surveying and Geodesy, Measuring & Mapping

Exhibition:

Exhibition Location:

Related Publication: American Journal of Science, Stanley, William Ford. Surveying and Leveling Instruments

Credit Line: Gerhard Derge

Data Source: National Museum of American History

Id Number: 1985.0798.01Accession Number: 1985.0798Catalog Number: 1985.0798.01

Object Name: miner's compass

Measurements: telescope: 17 3/4 in; 45.085 cmoverall: 8 3/4 in x 19 3/8 in x 8 1/2 in; 22.225 cm x 49.2125 cm x 21.59 cm

Guid: http://n2t.net/ark:/65665/ng49ca746a5-8b6a-704b-e053-15f76fa0b4fa

Record Id: nmah_762093

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