Koehler Trim-Numeral Calculator
date: label: date made
content: 1954
name: label: maker
content: Felsenthal Instrument Co.
notes: label: Description
content: This plastic green and white slide rule carries out calculations related to the capacity, draft, and resistance of cargo tankers able to carry up to 26,700 deadweight metric tons of petroleum or petroleum products. Eight metal rivets hold the rule together. The front is marked: KOEHLER TRIM-NUMERAL CALCULATOR (/) 26700 D.W.T. TANKERS. The bottom of the front of the slide is marked: MARKETED BY JEFKO PRODUCTS COMPANY, 100 OAKLAND ROAD, MAPLEWOOD, NEW JERSEY. The back of the rule and the back of the slide are both marked: COPYRIGHT 1954 BY J. F. KOEHLER.
label: Description
content: According to the accession file, this instrument was made by Felsenthal Instrument Company in 1954 as model number FDJ-23. For company history, see 1977.1141.01 and 1977.1141.02. The address for JEFKO Products is a single-family home constructed in 1925. A New Jersey engineer named J. Franklin Koehler (b. 1927) earned a B.S. in naval architecture and marine transportation from the Massachusetts Institute of Technology in 1951 with a thesis titled "Influence of Rising Operating Costs on Relative Economic Operation of Higher Speed Cargo Vessels."
label: Location
content: Currently not on view
place: label: place made
content: United States: Illinois, Chicago
topic: label: Subject
content: Mathematics
label: Subject
content: Rule, Calculating
label: Subject
content: Ships
setName: label: See more items in
content: Medicine and Science: Mathematics
label: See more items in
content: Science & Mathematics
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content: Slide Rules
creditLine: label: Credit Line
content: Gift of Ben Wharton Rau and Margery Felsenthal Rau
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1977.1141.38
label: catalog number
content: 336422
label: accession number
content: 1977.1141
objectType: label: Object Name
content: slide rule
physicalDescription: label: Physical Description
content: plastic (overall material)
label: Physical Description
content: metal (part material)
label: Measurements
content: overall: .3 cm x 29.8 cm x 10.2 cm; 1/8 in x 11 23/32 in x 4 1/32 in