What is this antique thing?

[W K Longcor]

I have reached a point in my life where I need to simplify and downsize. Been going through my old (antique) camera stuff to see what I might want to part with, and found this. It came to me with some camera/darkroom equipment. I have no idea what it is. Anybody got any ideas? I thought maybe some sort of hydrometer. But, in plain water, it floats with about 1/3 of the ball above the surface. Comes in a beautiful turned wooden case. Scale is hand etched 1 through 12. Then again it might not be photographic in nature at all!

[Vaughn]

My guess is that it measures the density of the liquid it is in -- with the number relating to specific densities.

[Jason Greenberg Motamedi]

Yes, it looks like a hydrometer. I have a similar looking one. Pretty, but hard to use compared to current glass models.

[LabRat]

With the linear scale, it might have been made for a specific product...

Steve K

[Dugan]

I could be wrong, but I think that's a dingle arm from a Turbo Encabulator. :)

[sharktooth]

I seem to recall you could use a hydrometer to check your fixer, but maybe I'm just confused. It might also be useful for gum bichromate.

[Tin Can]

Very common not that long

Chemists of all types had many

[John Layton]

Hmmm...I think you've hit the nail on the head - that what you have in an antique...thing!

[Maris Rusis]

If that hydrometer floats high in water it is calibrated for a liquid of a lower specific gravity. It could be for ethanol which in its pure form has a SG of 0.79.