Drafting Scale Rule

This wooden rule has eight scales for making scale drawings. On one side, scales for 1-1/2" = 1' and 3" = 1' are along the top. Scales for 3/8" = 1' and 3/4" = 1' are along the bottom. On the other side, scales for 1/2" = 1' and 1" = 1' are along the top. Along the bottom are scales for 1/8" = 1' and 1/4" = 1'.
The interior on both sides is marked: E. D. L. JR. for the previous owner of the rule, Erasmus Darwin Leavitt Jr. (1836–1916), the renowned American mechanical engineer and designer of steam engines.
Currently not on view
Object Name
scale rule
date made
ca 1900
Physical Description
wood (overall material)
overall: .3 cm x 32.2 cm x 3.2 cm; 1/8 in x 12 11/16 in x 1 1/4 in
place made
United States
ID Number
accession number
catalog number
Scale Rules
Science & Mathematics
Drafting, Engineering
See more items in
Medicine and Science: Mathematics
Scale Rules
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of Margaret van D. Rice
Additional Media

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