GM Model B Exposure Meter - how old?

[chromatic-aberration]

I picked up a GM Model B Exposure meter at the flea market today, and I was

wondering if anyone knew when these things were manufactured.

[chromatic-aberration]

...and the reverse:

[alex_lofquist]

I have lived in the Chicago area for many years, and have never heard of G-M Laboratories. From its Art-Deco appearance I'd guess it to have been built in the late thirties. It may have been manufactured to compete with the Weston Master for which it has a slight resemblence. I think that it is pretty cute!

[chromatic-aberration]

The nice thing is that it still seems to be working perfectly. It isn't calibrated for ASA film speeds though, so that's a clue right there that it's probably not postwar.

[kelly_flanigan1]

Pre war there were many film speeds; all abit different. GE speed; Weston speed; Kodak speed etc. ASA speed came out during ww2; a miltary way of standardizing the mess.

[kelly_flanigan1]

G-M Laboratories made pinball machines in Chicago in the 1930's; in a city that back then was a powerhouse of radio and photo makers too. G-M Laboratories was on Belmont avenue. GN made precision galvonometers for lab work; they made photolectric cells; they made relays; they made those giant suspended galvonometers we used in EE labs for bridge ciruit experiments; they also made lab stuff for botany testing; PH testing etc.

[alex_lofquist]

That's interesting info. Are they still in business? Or were they were taken over by General Radio or Leeds & Northrup?

[marc_bergman1]

Christopher,

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I found an ad in the February 1942 issue showing this meter.

<p>

I found another ad in the November 1940 issue. It is a full page ad announcing this meter for $8.75. It is on page 11. The face of the meter looks slightly different but it is a Model B.

<p>

The GE-48 listed for $21. The Weston Master 715 listed for $24. These are 1940 prices.

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[marc_bergman1]

This picture is from the February 1942 issue.