C-Thru W-30 Ruler Modified by Owner

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This five-inch portion of a clear plastic ruler has a scale of inches along the top, divided to 1/16", numbered by ones from 8 to 11 inside a 3X8 grid at each inch and numbered by ones from 2 to 5 below the grid. The bottom edge has a centimeter scale divided to millimeters and numbered by ones from 1 to 12. The rule is marked: C-THRU RULER COMPANY (/) Hartford, Conn. U.S.A. The C-Thru logo with the company name and a ruler inside a circle is to the left of the mark. The bottom edge and left and right ends have been cut into points.
Teacher Jennie Zachs established the C-Thru Ruler Company in Hartford in 1939. The firm was acquired by Acme United Corporation in 2012 and continues to make transparent drafting tools and drawing instruments, including model W-30. The donor, Sebastian J. Tralongo (1928–2007), served in the U.S. Navy during World War II and then worked for the Vitro Corporation in Rockville, Md., for 35 years. He patented a device for signaling from deeply submerged submarines. The object was received with several other drawing instruments in a wooden box, 1984.1071.13.
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/; "Tralongo, Sebastian James 'Subby'," Hartford Courant, May 26, 2007; Sebastian J. Tralongo, "Submarine Signal Device" (U.S. Patent 2,989,024 issued June 20, 1961); "Vitro Corp. – Company Profile," http://www.referenceforbusiness.com/history2/25/Vitro-Corp.html.
Currently not on view
date made
mid 20th century
C-Thru Ruler Company
place made
United States: Connecticut, Hartford
Physical Description
plastic (overall material)
overall: .1 cm x 12.7 cm x 2.6 cm; 1/32 in x 5 in x 1 1/32 in
ID Number
accession number
catalog number
Credit Line
Gift of Sebastian J. Tralongo
Rule, Measuring
Drafting, Engineering
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Scale Rules
Data Source
National Museum of American History


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