Mystery optics device

June 23, 2024 2:44 PM

What on earth is this device? It was found unlabeled in an antiques shop in North Adams, MA. It has a plaque on the base saying it made by Bausch & Lomb, so it's probably an optical device of some kind; but I'd like to know what, exactly.

A few more notes:

• It also had a plaque on the base saying that it ran on such-and-such voltage, current, etc. However, I did not see any electrical plugs coming out of it, nor was there any obvious place for a power cord to plug in.
• The device was heavy; I suspect the frame was cast iron.
• The device was about 18" long, end to end, and stood about 12" high.

Any speculation / educated guesses would be welcome!

posted by Johnny Assay to Science & Nature (9 answers total)

An antique ophthalmometer, something post-electricity? I think the electricity may have been to run a lamp or a photo camera.
posted by fiercekitten at 2:56 PM on June 23

Parts of it remind me of an old-school spectrometer, and those three pointy tips look like something you'd use to make a current arc from to get a sample to emit its spectral lines, but there are more wheels than this hypothesis makes sense of.
posted by heatherlogan at 3:04 PM on June 23

Probably a lensmeter or similar.
posted by zamboni at 3:23 PM on June 23 [2 favorites]

Best answer: Here's a good article on the what and how of focimiters/lensmeters/lensometers/vertometers.
posted by zamboni at 3:36 PM on June 23 [2 favorites]

those three pointy tips

Likely a marking device for unshaped lenses. From the Kerr article:

The operator, working with a lens that had not yet been shaped to fit into the frame, would (by observation with the optical system) properly center physically the optical center of the lens and orient the lens with its reference axis horizontal. Then, using the marking device, three small dots in temporary ink would be made on the lens, the center one at the optical center, and all three marking the horizontal reference axis.

posted by zamboni at 3:43 PM on June 23 [2 favorites]

There's a plaque on the second photo, on the other side of the base from the B&L logo. Was that just the electrical information?
posted by zamboni at 3:44 PM on June 23

Best answer: Flipping through the Kerr article, the mystery device strongly resembles the Bausch & Lomb Vertometer type 21-05-90 on p57.
posted by zamboni at 3:48 PM on June 23 [3 favorites]

Best answer: Zamboni has it I think. it's a lensometer.

Check out these photos of this Bausch and Lomb model 21-64-90

The similarities are obvious. including the 3 prongs and electrical info plate
posted by yyz at 4:12 PM on June 23 [2 favorites]

Best answer: It's a lensometer. I used to work in an optometrist's office and in addition to modern ones they kept an old-fashioned one in the optician's lab to double-check things as well as to torture opticians in training.
posted by terrapin at 5:34 AM on June 24 [1 favorite]