Has anyone seen these before

Discussion in 'General' started by vespa100, Feb 17, 2020.

  1. vespa100

    vespa100 Member

    These numbered and lettered rods came in a military collection but I can't work out what they are. They are probably not military but worth asking. Thanks for looking IMG_20200217_174535-1824x1368.jpg IMG_20200217_174638-1795x804.jpg IMG_20200217_174540-1920x2560.jpg IMG_20200217_174555-1713x621.jpg
    Charley Fortnum likes this.
  2. Charley Fortnum

    Charley Fortnum Dreaming of Red Eagles

    Actual knowledge: none.

    Pure and fevered speculation: some kind of two-way cipher method for generating codes.

    Do those holes look as thought they have/could receive pegs of some kind?

    How many rods and do they all begin with a unique single letter?
    timuk, Chris C and Dave55 like this.
  3. Robert-w

    Robert-w Well-Known Member


    They appear to be a late set of Napier's rods, also known as Napier's bones (because of the original material used). A very early calculating system first introduced in the early 17trh century but still in use in the early 20th. It gave rise to both the slide rule and log tables both of which were easier to use but less accurate. The tubular Otis King Calculator in the 20th century. finally produced a device with the convenience of a slide rule and the precision of Napier's rods. If in a military collection they could have been used by an engineer or an artilliarist but one who had a table to lay them out on

    A cyphering system would have alphabetic characters in greater numbers
    Dave55, Charley Fortnum and vespa100 like this.
  4. vespa100

    vespa100 Member

    Hi Charley that's what I was thinking there are 14 rods with different letters at the start when you rotate the rod the letters/numbers change.
    IMG_20200217_181714-1920x2560.jpg IMG_20200217_181718-1920x2560.jpg
    Charley Fortnum likes this.
  5. vespa100

    vespa100 Member

    Thanks very much I knew this forum could give me an answer
  6. Bin There

    Bin There Member

    Perhaps this fits the bill a bit better? The rods are parts of an early code slide rule. I have no idea who made it or which country may have used it.


    Each of your rods should have four sides with different characters and numbers. But you can see in this picture that rod X shows the side with the same characters as those shown on your rod X (first pic in post #4). I'm guessing if you roll your rods you can match them to the characters in this picture.

    Did the sleeve under them in your pictures come with these rods? And if so are there any markings on the sleeve?

    Hope this gives you a lead you can use.
    timuk, SDP, Chris C and 3 others like this.

Share This Page