Theodolite
name: label: maker
content: Troughton and Simms
notes: label: Description
content: The Proprietors of the Locks & Canals in Lowell, Mass., used this theodolite to lay out the canals that provided transportation and power for the textile mills in that city. It was probably made soon after 1826, when John Troughton took William Simms into partnership and began trading as Troughton & Simms. Exceot for its lack of magnifiers, it is identical to the theodolite described in F. W. Simms, <i>A Treatise on the Principal Mathematical Instruments</i> (London, 1836). The horizontal circle and vertical arc are silvered, and read by verniers to 20 seconds.
label: Description
content: The scale for "Diff. of Hypo. & Base" on the back of the vertical arc is used to correlate the angle of elevation or depression with horizontal distances when surveying sloping ground. The inscription reads "Troughton & Simms LONDON."
place: label: place made
content: United Kingdom: England, London
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
creditLine: label: Credit Line
content: Proprietors of the Locks and Canals on the Merrimack River
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: PH.314774
label: accession number
content: 211155
label: catalog number
content: 314774
objectType: label: Object Name
content: theodolite
physicalDescription: label: Measurements
content: overall: 13 1/2 in; 34.29 cm
label: Measurements
content: horizontal circle: 7 in; 17.78 cm
label: Measurements
content: needle: 3 in; 7.62 cm
label: Measurements
content: telescope: 13 1/4 in; 33.655 cm
label: Measurements
content: hanging level: 5 1/4 in; 13.335 cm