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    Re: Brown-Nassau Spherical computer
    From: UNK
    Date: 2014 Dec 4, 06:15 -0000


    I’ve been looking at the Verniers on the SI model and the incomplete diagrams in Luykx.

    The A Vernier is on the outer side, the X Vernier on the inner side to ensure it meets up against the correct scale?

    The B Vernier on the Luykx is on the inside, so presumably the Y Vernier (not shown, we need a photo of that side from SI) is on the outside?

    If we got the inside/outside positions correct, maybe I could add the white background with good old fashioned typex white paint?

    Might as well get it exactly right before I start on the next version?

    Thanks for everything



    From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Harri Ojanen
    Sent: 03 December 2014 16:31
    To: francisupchurch@gmail.com
    Subject: [NavList] Re: Brown-Nassau Spherical computer


    Hello Francis,

    Here are new versions quite close to the one in SI. Verniers and additional scales are now included. Actually the verniers in the SI model are quite subtle: they seem to be printed on top of a strip of white paint. Along the arc on the base plate there are two scales, one going from 0 to 90, and the other going the opposite direction. The white background of the vernier on the rotor always hides the scale which is not to be used with it. A nice way of preventing errors happening by using wrong combination of scale and vernier.

    Well, most printers don't have white ink, so I can't reproduce that. (Actually years ago I had a dye-sublimation printer, and there was white ink available for it - used when printing on colored paper. Similar devices might still be available, though probably quite rare.) For now one just has to be careful of using a scale and vernier combination where the numbers increase in the same direction on both.



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