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View Full Version : Spherometer Jinks & W.H.Reisner



Steven Tribe
31-Oct-2016, 03:31
I bought a basic Spherometer a few years ago in an attempt to work out the refractive index of the simple meniscus lenses used in the Puyo Anachromratique Objectif d'Artiste - with some success!

I am not happy about using a single instrument for measurement, so bought another, this time Vintage, Spherometer recently. Whilst the first Spherometer was very basic - fine screw threads and vernier scales - this one has dial display, gears and can measure both -ve and +ve instantly. Works well and has, apparently, a calibration lever at the side.

I would very much like to hear from anyone who has experience of this all-american product made W.H.Reisner of Hagerstown, MD.

In particular:

- Does the number stamped on the back represent serial number or is it a calibration number. Mine is 159.

- What does the inner ring of numerals mean? The "hour" hand moves when I zero set the "minute" pointer on plane glass.

- Do the measurements/readings represent metric or imperial measure which have to be incorporated into the usual formula. Or was it supplied with a table which "turned" the direct reading into a radius.

I must say that it is delightful example of american fine engineering!

Randy Moe
31-Oct-2016, 05:42
I'm sure you searched. I have no answer.

I searched to understand how one works. Found a great illustrated page.

http://americanhistory.si.edu/collections/object-groups/spherometers

Steven Tribe
31-Oct-2016, 06:43
Some lovely instruments there. Reisner seems to have a virtual monopoly - just 2 legs instead of the usual 3, and instant dial readings.