What is this odd Ground Glass? Use? Application?

[DanK]

Saw this on the auction site - credit to op

Odd looking Ground Glass - Does anyone know what it was used/designed for?

Thanks,
Dan

[Ari]

It looks like it's from the hippie era, possibly used to photograph a "love-in", maybe even a "be-in".

[Nathan Potter]

Hmmm, interesting. I'm guessing, but it might be a particle size counter. The 8 bins allow an observer to estimate the size of particles in the view then placed them in the correct bin for statistical analysis. Could also be used as a visual adjunct for percolation statistics.

Nate Potter, Austin TX.

[Maris Rusis]

It's a grain size comparator from a metallograph. I used to sell such things for the Reichert MeF2 inverted microscopes about 30 years ago.

[DanK]

Interesting. Thanks Maris...