slide rules

[Greg 'groggy' Lehey]

On Sunday, 18 May 2008 at 17:18:30 -0400, Jim Capozzoli wrote:
> So, I pulled out the slide rule yesterday that's older then I am..and
> I figured out how to multiply/divide on it.  Is there anybody out
> there still using slide rules for day to day math?  Or does anybody
> have any interesting stories/reminiscences about slide rules?  I was
> considering figuring out how to do Trig on it and then taking my Trig
> final with it. :)

Heh.  I don't know where my slide rule is, but it's definitely a lot
younger than I am.  So the following is from memory.  It applies to
the conventional slide rules that I know, with C/D scales going from 1
to 10 at the bottom, and A/B scales going from 1 to 100 at the top
(giving squares of the corresponding scale below).

To multiply two numbers, you place the 1 on the C scale (bottom of the
slide) against the first number on the D scale (directly below on the
body).  Move the cursor (or your eye :-) to the second number on the C
scale, and read off the result on the D scale.

To divide one number by another, you place the divisor the C scale
above the dividend on the D scale.  Read off the quotient on the D
scale below the 1 on the C scale.

Greg
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