Rowland Ruling Engine
date: label: date made
content: 1880-1882
name: label: maker
content: Rowland, Henry A.
notes: label: Description
content: This instrument has a rectangular wooden base, three metal supports, an iron frame. and parts of brass and other metals. At the back are two wheels. The smaller wheel moves along the threads of the engine's screw, which extends perpendicularly in front of and into the tron frame. The position of the screw determines the positon of a flat metal plate on which the grating is mounted. The second, larger wheel determines the motion of the stylus across this gratting (parallel to the front edge of the base). Four cylindrical cups attached to the mount for the stylus hold oil when the mechanism is to be oiled - wicks of string transmitt the oil. The small metal wheel at the back of the engine is graduated. A small metal wheel is disjoint from the engine.
label: Description
content: Henry A. Rowland (1848-1901) was appointed to the physics department at Johns Hopkins University in 1875, a year before the school formally opened. He had an engineering degree from the Rensselaer Polytechic Institute but was largely self-taught in physics. At the suggestion of a colleague, he began work on spectrum analysis and required a ruling engine to make finely ruled diffration gratings. This is one of the ruling engines made and used by machinists at Johns Hopkins under Rowland's direction. He used the gratings to produce photographs of the solar spectrum. Johns Hopkins also distributed them for use by other scientists. By 1894, Rowland had a total of three ruling engines, which continued in use for decades after his death.
label: Description
content: References:
label: Description
content: Accession File 304122.
label: Description
content: C. N. Brown, "Diffraction Gratings, Part 2. The Rowland Era and Beyond," <I>Bulletin of the Scientific Instrument Society</I>, #126, 2015, pp. 8-15. This paper cites several other useful sources.
label: Description
content: C. Evans, "Precision Engineering: an Evolutionary Perspective," MSc Thesis, Cranfiled Institute of Technology, 1987, esp. pp 104-107.
label: Location
content: Currently not on view
place: label: place made
content: United States: Maryland, Baltimore
topic: label: Subject
content: Mathematics
label: Subject
content: Ruling and Dividing Engines
setName: label: See more items in
content: Medicine and Science: Mathematics
creditLine: label: Credit Line
content: Gift of Johns Hopkins University, Department of Physics
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: MA.333877
label: catalog number
content: 333877
label: accession number
content: 304122
objectType: label: Object Name
content: Ruling Engine
physicalDescription: label: Physical Description
content: metal (mechanism material)
label: Physical Description
content: wood (base material)
label: Physical Description
content: glass (light bulb material)
label: Physical Description
content: string (wicks material)
label: Measurements
content: overall: 57 cm x 90 cm x 66 cm; 22 7/16 in x 35 7/16 in x 25 31/32 in