This wooden rectangular rule consists of an inch scale marked from zero to 6 and divided by tenths, a scale marked from zero to 50 and divided into units (10 units is approximately 3 cm), and diagonal scales for tenths and eighths. On the reverse side of the rule, there are scales of equal parts dividing the inch into 15, 20, 25, 30, 35, and 40. This side also contains a scale of chords. One edge of the rule is scalloped. There is no maker's mark, but the rule probably dates from the late 1800s or early 1900s.

The donor operated his family's building company, where he displayed his collection of 1200 hand tools.

Date Made: ca 1900

Location: Currently not on view

Subject: MathematicsDrafting, Engineering


See more items in: Medicine and Science: Mathematics, Science & Mathematics, Scale Rules


Exhibition Location:

Credit Line: The John R. Gerwig, Jr., Collection

Data Source: National Museum of American History

Id Number: 1977.1101.018Catalog Number: 1977.1101.018Accession Number: 1977.1101

Object Name: Rulescale rule

Measurements: overall: .1 cm x 15.4 cm x 3.4 cm; 1/32 in x 6 1/16 in x 1 11/32 in


Record Id: nmah_1127473

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