Comparator Made by Warner and Swasey for use by S.P. Langley
date: label: date made
content: ca 1900
name: label: maker
content: Warner & Swasey Company
notes: label: Description
content: Smithsonian Institution staff have long used instruments, made in both the United States and abroad, to record and to analyze scientific data. For example, in 1887 astrophysicist Samuel Pierpont Langley (1834 -1906) began working as assistant Secretary at the Smithsonian, while retaining his position as head of the Alleghany Observatory in Pittsburgh. He was promoted to the position of Secretary of the Smithsonian that same year, and a Smithsonian Astrophysical Observatory soon was under construction in Washington. Langley had invented a sensitive instrument called to bolometer to measure the intensity of solar radiation at various wavelengths. It produced records on glass plates 60 cm. long and 20 cm. wide. To measure these, Langley and his associates used this apparatus, called a comparator, and a microscope that moved along the carriage of the comparator (this microscope is not present in the museum object). This particular comparator was made for the Smithsonian by the firm of Warner & Swasey Co. of Cleveland, Ohio.
label: Description
content: References:
label: Description
content: S. Pierpont Langley, <I>Annals of the Astrophysical Observatory of the Smithsonian Institution</I>, vol. 1, 1900, pp. 64-65.
label: Description
content: Donald L. Obendorf, <I>Samuel P. Langley, Solar Scientist, 1867-1891</I>, PhD. Dissertation, Berkeley: University of California, 1969
label: Location
content: Currently not on view
place: label: place made
content: United States: Ohio, Cleveland
topic: label: Subject
content: Mathematics
label: Subject
content: Astronomy
setName: label: See more items in
content: Medicine and Science: Mathematics
creditLine: label: Credit Line
content: Transfer from Smithsonian Institution Astrophysical Observatory
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: MA.314884
label: accession number
content: 211531
label: catalog number
content: 314884
objectType: label: Object Name
content: Comparator
physicalDescription: label: Physical Description
content: metal (overall material)
label: Measurements
content: overall: 17 1/2 in x 36 in x 12 in; 44.45 cm x 91.44 cm x 30.48 cm