Date: Tue, 20 May 2008 10:14:23 -0400 From: John Brann <john@brann.org> To: chat@freebsd.org Subject: Re: slide rules Message-ID: <20080520141423.GA33386@freebie.brann.org> In-Reply-To: <20080519035209.GT46655@dereel.lemis.com> References: <37f72b1f0805181418j16efd60fge243160dbfdc6789@mail.gmail.com> <20080519035209.GT46655@dereel.lemis.com>
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On Mon, May 19, 2008 at 01:52:09PM +1000, Greg 'groggy' Lehey wrote:
> 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
> --
> See complete headers for address and phone numbers.
I'm afraid I don;t use it much - but I still have mine to hand. It's on my
desk, in New York City, with a cricket ball. Both objects are there to
confuse the locals. Both succeed.
John
--
Unreal City,
Under the brown fog of a winter dawn,
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