A strange instrument?

Can you help identify this item?

Query by Bill Clarke, Director Restigouche Regional Museum
Dalhousie, N.B.Canada.


Micscape received this interesting query from Bill Clarke,
and we share it with our readers in case someone can help.

Bill writes:

I'll try to describe this thing as best I can. One of my friends, a former radio announcer, believes it's a cross between a microscope and a microphone. As it is in the picture, it's about 11.5 inches high and 14 inches from end of lamp housing to top of ocular. I don't see a maker's name, but the trademark in the form of a double convex lens with a triangle through it has the initials N M. Under this is Tokyo, Japan. No. 10360.

There is a dial around the tube below that plate near the ocular. It is calibrated 0 to 180 - obviously degrees. Just above the ocular there is another small lens which magnifies the figures on that dial.

At the side, there is a knob calibrated from -25 to +25. Turning this moves the lamp in and out. There's also a device which is out of the way, but can move into the line of sight. It has three sharp pins on it. No obvious purpose I can imagine.

Between the tube housing and the ocular, etc., there is a spring loaded affair that moves down to the lens at the end of the tube coming from the lamp. In addition, there is what I would have to call a stave. Its surface, however, is parallel to the line of sight. It moves up and down, that is, closer to line of sight or farther away. When looking through the instrument, there are two concentric red circles, almost like something on a bomb sight. There are also cross hairs which rotate when turning the dial around the tube. They also go in and out of focus.

This thing isn't ancient, or it wouldn't be electric. Still, it's certainly not a microscope for any normal purpose. I saw a picture of an older instrument which had a faint resemblance to this one. The person who was selling it thought it was for determining the prescription of existing eyeglasses, but admitted it was only a guess. Could this be something similar?

As I explained earlier (Editor: in an earlier e-mail), we had been planning on using some of our microfiche readers as if they were microscopes. When someone donated a Wild M40, we decided on an exhibition that would serve as an introduction to microscopy. We've managed to put together a small collection of microscopes. Most are toys, but a couple are good ones and we will have some from the late 1800s. This thing was added to our collections at that time, but it doesn't answer any descriptions I've been able to find. In other words, I need help!

Comments to Bill Clarke welcomed.

Bill Clarke, Director Restigouche Regional Museum Dalhousie, N.B. Canada.

Editor's note added June 16th 2000. Many thanks to the readers who responded with information regarding this unit. It is probably as the seller thought, i.e. for determining the prescription of existing eyeglasses and is known as a lensometer. An American Optical lensometer made in 1921 is shown on Dick Whitney's fascinating 'American Optical History' web site at http://web.meganet.net/dickwhitney/aoscientif.htm.

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Published in the June 2000 edition of Micscape Magazine.

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