C-Thru Pocket Slide Rule

Description
This inexpensive five-inch white plastic rule has A and D scales on the front of the base; B, CI, and C scales on the front of the slide; and S, L, and T scales on the back of the base. The indicator is clear plastic. Underneath the slide is a table of equivalents and settings. The front of the slide also has a scale of six inches, divided to sixteenths of an inch, and a scale of 15.3 centimeters, divided to millimeters. The back of the slide has a table of decimal equivalents from 1/64 to 63/64. A brown imitation leather sheath is marked: POCKET SLIDE RULE MADE IN U.S.A. No. 27. For instructions, see 1988.0807.06. The postal code on the instructions indicates a date between 1943 and 1963. According to this sheet, the C-Thru Ruler Company of Hartford, Conn., made this rule. This firm, established in 1939 by teacher Jennie Zachs and acquired by Acme United Corporation in 2012, continues to make transparent drafting tools and drawing instruments.
References: Brian Dowling, "Acme United Acquires Bloomfield's C-Thru Ruler," Hartford Courant, June 11, 2012; "About Us," C-Thru Ruler Company, http://www.cthruruler.com/.
Location
Currently not on view
Object Name
slide rule
date made
1943-1963
maker
C-Thru Ruler Company
Physical Description
plastic (overall material)
Measurements
overall: .4 cm x 17 cm x 4.4 cm; 5/32 in x 6 11/16 in x 1 23/32 in
place made
United States: Connecticut, Hartford
ID Number
1988.0807.02
accession number
1988.0807
catalog number
1988.0807.02
subject
Science & Mathematics
Mathematics
Slide Rules
Rule, Calculating
Education
See more items in
Medicine and Science: Mathematics
Slide Rules
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of George A. Norton
Additional Media

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