Patent Model for Triangular Drafting Scale Invented by Josiah Lyman
date: label: date made
content: 1863
name: label: maker
content: Lyman, Josiah
notes: label: Description
content: Both edges of one side of this German silver triangular rule have scales divided to 1/40" and numbered by twos from 3 [<i>sic</i>] to 24 and by ones from 1 to 6. This side is marked: In. 40. U.S. STD. It is also marked: Josiah Lyman, Lenox, Mass.
label: Description
content: Both edges of the second side have scales divided to 1/24" and numbered by ones from 1 to 12 and from 1 to 6. This side is marked: In. 24. U.S. STD. Both edges of the third side have scales divided to 1/20" and numbered by ones from 1 to 10 and from 1 to 5. This side is marked: Ft. 200. U.S. STD.
label: Description
content: One end has a micrometer screw. According to the patent, there should be three interchangeable micrometer circles, but only one is present. The other end is supposed to have a thumb-nut, but the tube that would hold it is broken. Three large holes are in the center of each side. Three pinholes are in each end.
label: Description
content: Among other inventions, Josiah Lyman (1811–1889) patented a protracting trigonometer (U.S. Patent 20,356 issued May 25, 1858). See MA.328738. This triangular rule was supposed to have a brass spring attachment that would hook into the pin holes at each end of the rule and then around the trigonometer, making the rule a sliding scale for the trigonometer. Lyman argued that placing a weight on the arm of wire stretching across the trigonometer would make the sliding scale mathematically reliable. He claimed that the micrometer scale, together with the protracting trigonometer, could measure off the twelve-thousandth part of a line 12 inches long.
label: Description
content: References: Josiah Lyman, "Improvement in Drafting Scales" (U.S. Patent 38,904 issued June 16, 1863); Peggy A. Kidwell, "Josiah Lyman's Protracting Trigonometer," <i>Rittenhouse</i> 3 (1988): 11–14.
label: Location
content: Currently not on view
place: label: place made
content: United States: Massachusetts, Lenox
topic: label: Subject
content: Mathematics
label: Subject
content: Patent Models
label: Subject
content: Drafting, Engineering
setName: label: See more items in
content: Medicine and Science: Mathematics
label: See more items in
content: Science & Mathematics
label: See more items in
content: Scale Rules
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: MA.308918
label: accession number
content: 89797
label: catalog number
content: 308918
objectType: label: Object Name
content: rule, triangular
label: Object Name
content: scale rule, triangular
label: Object Type
content: Patent Model
physicalDescription: label: Physical Description
content: german silver (overall material)
label: Measurements
content: overall: 2.6 cm x 19.5 cm x 2.6 cm; 1 1/32 in x 7 11/16 in x 1 1/32 in