Midget Slide Rule Part 3
published 2025-12-31
by Christopher Howard
I tried a few square root problems with the A Scale. The A Scale is fairly simple, except one must remember whether to use the first or the last half of the scale, depending on the number of significant digits.
The Midget slide rule has a Binary Scale, which is basically the A Scale but with fractions marked out instead of the decimals. Working with the Binary Scale is a bit complicated mentally, as (1) not all the marks have fraction labels, so you sometimes have to work out in your head (or on paper) what the intermediate marks represent; and (2) there is a change on order of magnitude between the Binary Scale and the A Scale, so e.g. 1/4 on the Binary Scale points to 2.5 on the A Scale.
The Log-Log Scale, for calculating powers, is straightforward, so long as the number being raised to a power is between 1.5 to 1000000. It is possible to use numbers outside this range, and not terribly difficult, but that involves a few more steps involving dividing or multiplying factors.
The Midget has a Fraction Scale for adding and subtracting fractions, which is straightforward and might save you a few steps, as opposed equalizing the denominators, etc. Offhand, I can't remember the last time I had to do any complicated addition of fractions. But I could see how it might be used with something like (1) adding dimensions in inches, or (2) doing calculations involving musical scales.
💡 I wonder, could there be... a slide rule for musicians! A brilliant idea! Oh wait, somebody else already thought of it:
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This work © 2025 by Christopher Howard is licensed under Attribution-ShareAlike 4.0 International.