Sexton's Omnimetre Circular Slide Rule
date: label: date made
content: 1938
name: label: maker
content: Theodore Alteneder and Sons
notes: label: Description
content: This paper circular rule consists of two paper discs, a celluloid indicator, and a metal screw that holds everything together. Going out from the center of the rotating discs, there are scales of versed sines [3 yellow circles labeled from 3 to 80 degrees—the versed sine of an angle x is (1 - sin x)], the fifth power of N (5 white circles labeled from 1 to 9.5), tangents (3 yellow circles labeled from 5 degrees through 84 degrees), N cubed (three white circles labeled from 1 through 9.5), sines (two circles labeled from 6 to 84 degrees), N squared (two circles labeled from 1 to 95), secants (one yellow circle labeled from 10 degrees to 84 degrees), and a logarithmic B scale running from 1 to 10. On the base disc is a logarithmic A scale, running from 1 to 10, and an equally divided scale for finding logarithms that runs from 0 to 10. THoles in the base make it easier to rotate the disc.
label: Description
content: The base disc is marked around the edge: SEXTON'S OMNIMETRE; COPYRIGHT IN THE UNITED STATES 1896. ENTERED AT STATIONERS HALL LONDON FOR INTERNATIONAL COPYRIGHT 1896; NUMERI MUNDUM REGUNT; ENTERED ACCORDING TO ACT OF THE PARLIAMENT OF CANADA IN THE YEAR 1896 BY THADDEUS NORRIS, ENLARGED AND REVISED EDITION. The smaller disc is marked near the center: ALL RIGHTS RESERVED (/) PATENT 1895 U.S. CANADA & EUROPE. The back of the instrument is engraved: THEO. ALTENEDER & SONS (/) PHILADELPHIA. DANKERS is handwritten near the center of the back.
label: Description
content: Albert Sexton was a resident of Philadelphia who, according to his own account, read a lecture delivered by Colman Sellers at the Franklin Institute on 20 May 1891. Although the subject of the lecture was the utilization of the power of Niagara Falls, Sellers also mentioned the advantages of the slide rule. Intrigued by these comments, Sexton began to acquire slide rules. He concluded that a less expensive, more complete instrument was needed, and he designed one. When he provided samples to gentlemen visiting a local steam engine manufacturer, Southwark Foundry and Machine Company, he found they were most interested. Arthur Marichal, a Belgian civil engineer, wrote on his sample “Sexton’s Omnimetre” and added the Latin phrase “Numeri Mundum Regunt.” Sexton adopted both the name and the motto.
label: Description
content: With the assistance of Philadelphia resident Thaddeus Norris, Sexton introduced several versions of his instrument, including the most complete form, which is represented by this object. Sexton (and Norris posthumously) received the John Scott Medal of the Franklin Institute on 4 January 1899. The instrument was manufactured by the Philadelphia firm of Theodore Alteneder & Sons. The different forms sold for $1.00 to $3.00 around 1900, and this version sold for $4.00 by 1940.
label: Description
content: The donor acquired this example in 1938, when he joined the U.S. Navy’s Preliminary Ship Design Branch. He used it in the design of ships from PT boats to aircraft carriers, until his retirement in 1968.
label: Description
content: References: Peggy A. Kidwell, "Computing Devices, Mathematics Education and Mathematics: Sexton's Omnimetre in Its Time," <i>Historia Mathematica</i> 36 (2009): 395–404; Thaddeus Norris, "Marker for Slide-Rules" (U.S. Patent 540,184 issued May 28, 1895).
label: Location
content: Currently not on view
place: label: place made
content: United States: Pennsylvania, Philadelphia
topic: label: Subject
content: Mathematics
label: Subject
content: Rule, Calculating
label: Subject
content: Patented
label: Subject
content: General Calculation
setName: label: See more items in
content: Medicine and Science: Mathematics
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content: Science & Mathematics
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content: Trigonometry
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content: Slide Rules
creditLine: label: Credit Line
content: Gift of George A. Dankers, Jr.
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 2008.3041.01
label: nonaccession number
content: 2008.3041
label: catalog number
content: 2008.3041.01
objectType: label: Object Name
content: slide rule
physicalDescription: label: Physical Description
content: paper (overall material)
label: Physical Description
content: plastic (cursor material)
label: Physical Description
content: metal (part material)
label: Measurements
content: overall: 1 cm x 19 cm x 19 cm; 3/8 in x 7 1/2 in x 7 1/2 in