Object Details
- Perry Graf Corporation
- Description
- 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.
- 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.
- 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.
- Location
- Currently not on view
- Credit Line
- Transfer from Smithsonian Institution Libraries
- ca 1941
- ID Number
- 1983.3009.04
- catalog number
- 1983.3009.04
- nonaccession number
- 1983.3009
- Object Name
- calculating rule
- slide rule
- Physical Description
- metal (part material)
- paper (overall material)
- Measurements
- overall: 9.5 cm x 9.5 cm x .1 cm; 3 3/4 in x 3 3/4 in x 1/32 in
- place made
- United States: Illinois, Maywood
- See more items in
- Medicine and Science: Mathematics
- Science & Mathematics
- Slide Rules
- National Museum of American History
- Subject
- Rule, Calculating
- Promotional Item
- Farming
- Mathematics
- Record ID
- nmah_694150
- GUID (Link to Original Record)
- https://n2t.net/ark:/65665/ng49ca746a5-0f79-704b-e053-15f76fa0b4fa
