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Slide Rules

The slide rule is the iconic instrument of the engineering profession. Every significant human-built structure of the past 150 years has involved its use. Invented at the time of the Mayflower, the “modern” slide rule (sometimes called the “Mannheim Rule”) dates to 1850, just a decade before MIT was founded. In the 19th century, the popularity of the slide rule grew along with the engineering profession, which needed a reliable means of quickly and accurately completing tedious but essential calculations. The ubiquitous engineer’s rule was the Log Log Duplex Decitrig. As described in Keuffel and Esser’s brochure, How to Choose a Slide Rule: “It has every scale you need for riding through a tough engineering course with a minimum of headaches. It will serve you well throughout the years to come when you graduate and take your place in the profession. For real knock-down-and-drag-out, math-eating, fire-breathing engineering, there isn’t another slide rule in the world that can touch it.”

Classroom Demonstration Slide Rule
Pickett N500-ES, Pickett & Eckel, Inc.
c. 1964

photo: Michael Cardinali for MIT Museum

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  • I have a Web page at with some non-standard virtual slide rules. There is some good math in their explanation. Included are a slide rule to find the third side of a right triangle and one to add velocities relativistically.

    5 May 11 at 1:06 pm
  • I have a never been used, in the original shipping box with 2 instruction manuals, yellow Pickett All American Yellow classroom demonstration slide rule, about 4 feet long.

    I am looking to sell it, but not sure where. I was wondering if you could direct me? Thank you,

    Mary Klein

    Mary Klein
    30 Oct 12 at 9:48 pm
  • Hi Mary-I would potentially be interested in the slide rule if it is still for sale? You can contact me at


    8 Jul 13 at 2:40 pm