Acreage Worked Circular Slide Chart by Perrygraf for Allis-Chalmers
date: label: date made
content: ca 1941
name: label: maker
content: Perry Graf Corporation
notes: label: Description
content: The base of this orange, black, and white cardboard circular chart has scales for the number and size of plows and for the size of combines, planters, or harrows. Riveted to the rectangular base is a disc with a scale of tractor speed in miles per hour. Setting the dial for the appropriate tractor speed opposite the size and type of machinery employed reveals the approximate number of acres worked per day.
label: Description
content: According to its markings, Perry Graf Corporation of Maywood, Ill., copyrighted this "Tractor Calculator" in 1938 and made it for the Allis-Chalmers Manufacturing Company's Tractor Division in Milwaukee, Wis. A curator's note indicates the copyright was not issued until November 27, 1941. Perrygraf (spelled variously as "Perrygraf" and "Perry Graf") designed special purpose "slide charts," which were often distributed by manufacturers to their customers.
label: Description
content: The back of the calculator contains an advertisement for Allis-Chalmers, titled: WORK-PER-DAY THE A-C WAY. For other rules distributed by Perrygraf, see 1983.3009.06 and 1996.3029.01.
label: Location
content: Currently not on view
place: label: place made
content: United States: Illinois, Maywood
topic: label: Subject
content: Rule, Calculating
label: Subject
content: Promotional Item
label: Subject
content: Farming
label: Subject
content: Mathematics
setName: label: See more items in
content: Medicine and Science: Mathematics
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content: Science & Mathematics
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content: Slide Rules
creditLine: label: Credit Line
content: Transfer from Smithsonian Institution Libraries
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1983.3009.04
label: catalog number
content: 1983.3009.04
label: nonaccession number
content: 1983.3009
objectType: label: Object Name
content: calculating rule
label: Object Name
content: slide rule
physicalDescription: label: Physical Description
content: metal (part material)
label: Physical Description
content: paper (overall material)
label: Measurements
content: overall: 9.5 cm x 9.5 cm x .1 cm; 3 3/4 in x 3 3/4 in x 1/32 in