Railroad Compass
name: label: maker
content: W. & L. E. Gurley
notes: label: Description
content: W. & L. E. Gurley introduced this type of instrument--a railroad compass with one vernier on the limb--in 1868. This example has a hand-engraved signature, and so was made before the middle of 1876, when Gurley’s engraving machine was up and running. The upper plate carries the sights, two level vials, and the compass. The lower plate, wider than the upper, carries the circle, which is graduated to 30 minutes and read by vernier to single minutes. A tangent screw on the south arm moves the two plates relative to one another. A variation arc on the compass face extends 30 degrees either way. The folded vernier is moved by a rack and pinion located on the north arm, and reads to 2 minutes. The compass has a blackened or bronzed finish, and a silver–plated face. New, it cost $65.
label: Description
content: The "Fagg & Bowe 1870" signature scratched on the inside of this compass refers to George S. Fagg and Archibald H. Bowe, who began working for Gurley in 1866. The "Edward Meister Baltimore 1872" signature refers to an independent instrument maker in Baltimore, Md. The "Geo. Shilling 1904 Wash. D.C." signature refers to an independent instrument maker in Washington, D.C. The "J. Heim 1885" signature has not been identified.
label: Description
content: Ref: W. & L. E. Gurley, <i>A Manual of the Principal Instruments Used in American Engineering and Surveying</i> (Troy, N. Y., 1868), pp. 52–56.
label: Description
content: W. Skerritt, "W. & L. E. Gurley's Engraving Machine," <i>Rittenhouse</i> 11 (1997): 97–100.
label: Location
content: Currently not on view
place: label: place made
content: United States: New York, Troy
setName: label: See more items in
content: Medicine and Science: Physical Sciences
label: See more items in
content: Surveying and Geodesy
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content: Measuring & Mapping
publisher: label: Related Publication
content: W. & L. E. Gurley. Manual of the Prinicipal Instruments Used in American Engineering and Surveying; 11th Edition
creditLine: label: Credit Line
content: Virginia Polytechnic Institute
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: PH.330532
label: catalog number
content: 330532
label: accession number
content: 293490
objectType: label: Object Name
content: Surveyor's Compass (Railroad)
physicalDescription: label: Measurements
content: overall length: 15 1/2 in; 39.37 cm
label: Measurements
content: needle: 5 in; 12.7 cm
label: Measurements
content: overall: 11 in x 14 7/16 in x 8 1/4 in; 27.94 cm x 36.67125 cm x 20.955 cm