Transit and Equal Altitude Instrument
name: label: maker
content: Ellicott, Andrew
notes: label: Description
content: Andrew Ellicott (1754-1820) was the leading geodetic surveyor in the United States in the early years of the Republic, and he aimed to produce surveys that compared favorably with those done by the best Europeans in the field. In his words, the transit and equal altitude instrument was "the most perfect, and best calculated for running straight lines." Moreover, "when the different verifications are carefully attended to, [it] may safely be considered as absolutely perfect."
label: Description
content: Ellicott made this instrument, and used it to run the western boundary of New York in 1789, the boundaries of the District of Columbia in the early 1790s, the southern boundary of the United States in 1796-1800, and the boundary between Georgia and North Carolina in 1811. Ellicott took this instrument with him to West Point, when he became professor of mathematics at the U.S. Military Academy in 1813. A descendant, Andrew Ellicott Douglass, deposited it with the Smithsonian in 1898.
label: Description
content: This instrument, marked "Andw Ellicott Philadelphia," is modeled on the transit and equal altitude instrument that had been made by John Bird in London, purchased by Thomas Penn in 1763, and used by Mason and Dixon for their survey of the boundary between the colonies of Maryland and Pennsylvania. Ellicott had used this English instrument in 1784, when he was part of the team of American surveyors who extended the Mason-Dixon line to the western edge of Pennsylvania.
label: Description
content: Ref: Andrew Ellicott, "A Letter to Robert Patterson," <i>Transactions of the American Philosophical Society</i> 4 (1799): 32-51.
label: Description
content: Andrew Ellicott, "An Account of the Apparatus used on the Boundary between the United States and His Catholic Majesty," <i>Transactions of the American Philosophical Society</i> 5 (1802): 204-208.
label: Description
content: Silvio Bedini, "Andrew Ellicott, Surveyor of the Wilderness," <i>Surveying and Mapping</i> (June 1976): 113-135.
label: Location
content: Currently not on view
place: label: place made
content: United States: Pennsylvania, Philadelphia
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: American Philosophical Society. Transactions of the American Philosophical Society
label: Related Publication
content: American Philosophical Society. Transactions of the American Philosophical Society
label: Related Publication
content: American Congress on Surveying and Mapping. Surveying and Mapping
creditLine: label: Credit Line
content: Andrew Ellicott Douglass
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: PH.152080
label: accession number
content: 116914
label: catalog number
content: 152080.01
objectType: label: Object Name
content: transit and equal altitude instrument
physicalDescription: label: Measurements
content: overall: 18 1/4 in; 46.355 cm
label: Measurements
content: axis: 16 in; 40.64 cm
label: Measurements
content: overall: 93 in x 50 in x 80 in; 236.22 cm x 127 cm x 203.2 cm