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Posers and Puzzles

Posers and Puzzles

  1. Subscriber jb70
    State of Confusion
    20 Jun '15 09:56
    I have an old wooden slide rule with no maker's name.
    It has the symbol for pi,but it also has a symbol marked at 2.06,3.44 and 6.38 (subject to the accuracy of my reading the values).The symbol looks like O with a line slanted underneath to make the whole thing look like a slanted P and the O has n just above it like a power.
    On the back of the slide rule there are tables for weights/cubic foot for different substances,and strengths,tension,compression and shearing.
    Any ideas?
  2. 20 Jun '15 21:09
    Originally posted by jb70
    I have an old wooden slide rule with no maker's name.
    It has the symbol for pi,but it also has a symbol marked at 2.06,3.44 and 6.38 (subject to the accuracy of my reading the values).The symbol looks like O with a line slanted underneath to make the whole thing look like a slanted P and the O has n just above it like a power.
    On the back of the slide rule th ...[text shortened]... /cubic foot for different substances,and strengths,tension,compression and shearing.
    Any ideas?
    Sounds like the p' and p'' marks, as described (albeit, AFAICT, slightly wrongly) here: [url]http://www.sphere.bc.ca/test/scales.html[/url] and here: [url]http://sliderulemuseum.com/SR_Terms.htm[/url]. The third one I don't know, but if it's 6.28 rather than 6.38, it's 2pi.

    A picture would be useful.
  3. Subscriber jb70
    State of Confusion
    21 Jun '15 09:07
    Originally posted by Shallow Blue
    Sounds like the p' and p'' marks, as described (albeit, AFAICT, slightly wrongly) here: [url]http://www.sphere.bc.ca/test/scales.html[/url] and here: [url]http://sliderulemuseum.com/SR_Terms.htm[/url]. The third one I don't know, but if it's 6.28 rather than 6.38, it's 2pi.

    A picture would be useful.
    Thanks Shallow Blue.
    This must be it from one of your links:
    Q or δ or ρ"- Gauge Mark, generally on the C scale denoting seconds in a radian in the French decimal system 636620 ( my reading 6.38 ) = (200 x 100 x 100)/π. Sometimes described as graduated in the French decimal system.
    Q' or δ' delta' - Gauge Mark, generally on the C scale denoting minutes in a radian 3437.74 ( my reading 3.44) = (180 x 60)/π
    Q'' or δ" delta" - Gauge Mark, generally on the C scale denoting seconds in a radian 206265 ( my reading 2.06) = (180 x 60 x 60)/π