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Fri, Aug. 21st, 2009, 02:09 pm
What's this?

So I've figured out what the mysterious symbol in this picture means, but I don't know what it's called or the derivation of the symbol. Any thoughts?

From Misc
(Deleted comment)

Fri, Aug. 21st, 2009 06:14 pm (UTC)
530nm330hz

No, I mean the figure at 1.745 on the A/B scales. (Technically, it's at 0.0174532)

Fri, Aug. 21st, 2009 06:28 pm (UTC)
michelel72

Maybe grad??? (I got there from the Wikipedia page on "radians", and maybe the symbol is meant to be a "G" for grad? I'm taking a complete flyer on that.)

Fri, Aug. 21st, 2009 06:35 pm (UTC)
530nm330hz

Interesting idea, but since the symbol represents the ratio of one degree to 1 radian, I don't think grads will show up here.

But a stylized "g" was certainly where I started.

Fri, Aug. 21st, 2009 06:37 pm (UTC)
lucretia_borgia

I assume you've seen this. I looked in the manual for my Sterling, but the symbol isn't on the rule. I can't find my circular slide rule, which is disturbing, but the manual was also still there in its case. Lot of good that does. It had some really, really useful chemistry/physics constants and metric/British (well, American now, I guess, since the Brits have some sense) unit conversions.

Fri, Aug. 21st, 2009 06:41 pm (UTC)
530nm330hz

I had not found that page. A stylized rho to mean radians? Plausible.

This is a Danish slide rule by Ole Jørgensen, for what that's worth.

Fri, Aug. 21st, 2009 06:44 pm (UTC)
530nm330hz

And it appears to actually be a collectable with non-trivial value. Not that I plan to sell it; it has sentimental value to me.

Fri, Aug. 21st, 2009 06:42 pm (UTC)
sethg_prime

Could this be a stylistic variant of ϑ (U+03D1 GREEK THETA SYMBOL)?
(Deleted comment)

Fri, Aug. 21st, 2009 09:25 pm (UTC)
fauxklore: Mystery Solved!

I don't know what the symbol is called, but I have figured out a simple and logical (elegant, even) explanation for it.

It is used to convert between degrees and radians, right? In fact, to TURN degrees into radians.

Now, take the symbol for degree - that little raised circle thing.

The symbol for radian is the letter "r".

TURN the "r" upside down and attach it to the degree sign - and voila!

So, basically, it is rebus.


Sat, Aug. 22nd, 2009 03:13 am (UTC)
rymrytr

You could send a picture and request to
http://www.rekeninstrumenten.nl/index.html
the Danish Slide Rule Collector's Museum and Group.

Email = Otto van Poelje poelje@rekenlinialen.org