Cogar Thermotechn. 2512 Linear Slide Rule

Cogar Thermotechn. 2512 Linear Slide Rule

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Usage conditions apply
This one-sided linear slide rule has a wooden core coated with plastic, a plastic cursor, and a paper label stuck to the back. The scales are 25 cm. long (extended somewhat to both the left and the right). They are not lettered. The beveled top edge of the rule has a scale of equal parts 27 centimeters long divided to.1 cm. for the first 20 centimeters and to.05 centimeters from 20 to 27. Below this, still along the beveled edge, is a scale of inches, divided to.02 inches.
The first logarithmic scale runs from 1 to 100 in 25 cm. and from.7 to 120 over its full length. The lower part of the base has a scale running from 1 to 10 over 25 centimeters and from.9 to 11 overall. It is used for finding squares and square roots. Below this is a scale for finding square roots of the difference between 1 and the square of x. It runs down from.995 to 0.The slide has a scales that runs from.7 to 120, a scale that runs from 12 down to.9, and a scale that runs from.9 to 11. The reverse side of the runner has scales that run from 1.01 to 1.2, from 1.1 to 3.2, and from 2.5 to 10. The back of the rule suggests how it is used and lists various constants.
The rule fits in a black cardboard box.
According to the donor, this rule was made by prisoners in a Hungarian prison.
Currently not on view
Object Name
slide rule
place made
Physical Description
wood (base, slide material)
plastic (coating, runner material)
paper (stickers, box material)
overall: 2.2 cm x 30.7 cm x 4.6 cm; 7/8 in x 12 3/32 in x 1 13/16 in
ID Number
catalog number
accession number
Credit Line
Gift of Laszlo Kutor
Rule, Calculating
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Slide Rules
Data Source
National Museum of American History
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