bureauofstandards

Some kind of injection array for a particle accelerator or other physics experiment?

Close Clark, but I'd say it's a spectroscope or spectrometer -- possible a prototype for a calutron mass separator for radionuclides... The it could be from the astronomy department of a university used for studying the spectra of stars & nebulae.

I agree that it seems to be a spectrometer. Note the light bulb at the right rear of the apparatus.

This one raises a whole lot of questions. It looks to me like each tube ends in a light bulb, a diffuser, and a rotating shutter. Are all the rotating shutters connected to a drive shaft, to operate in sync, driven by the motor and chain coming up from below? Are the seven tubes optics to collimate the light sources? There seem to be some spare ones at the far left. Why seven? What would you want to illuminate with a pulsating light source? The man seems to be holding a lens, so my guess is that the black apparatus with the gears is where the results would be photographed or filmed. There's a rectangular gate (at the focal plane?) with a strange-shaped mask inside. I think the small telescope-like device at the left end could be a critical focusing magnifier.

I think this is probably at the National Bureau of Standards. See www.loc.gov/pictures/resource/npcc.15853/?co=npco for a room with the same trim on the walls including brickwork below the lower stripe.

Some obscure orchestral noisemaker?

The pensive guy is holding a small slab of marble, or some other veined stone. It looks like the big wheel is designed to clamp a whole series of slabs of the same size into a rotating jig. In the high-res view you can see the slabs are a few different varieties of stone. It's a little hard to see what those roller-like things underneath are doing; but perhaps there's a spinning drum to grind or polish the surfaces of the slabs.

Perhaps someone was testing and comparing types of stone for abrasion-resistance. Selecting which one to use for stair treads in public buildings?

The slabs look mostly like marble (which is not a great choice for stairs btw.) Nonetheless, perhaps they wanted to find the hardest batches. Maybe one of the rollers underneath is in fact some kind of abrasion tester. Floors could be another application.

A Bureau of Standards publication from 1933 is titled Wear Resistance of Natural Stone Flooring nvlpubs.nist.gov/nistpubs/jres/11/jresv11n5p635_A2b.pdf A quick skim suggests this report shows and describes different equipment and tests but does confirm that the agency did related work.