Panel mount terminal block

I recall them as "Number 6" batteries (cells). They were a fair bit taller than a can of beer. More like a tall-boy (or maybe even a bit taller).

Some years ago, I was involved in a project where the power supply guys opted to use a bunch of similarly sized cells to give an incredibly low output impedance for the 20V supply (which had to deal with a 400Hz 20A load, repeatably) Made the power supply ungodly heavy!

Unfortunately, nothing to provide an *obvious* cue as to actual size (though I suspect you could assume the paper clips are the "original size" paper clips, measure one of those and extrapolate from there).

yeah, I found this web site, the guy seems to be a fan, down the bottom there's some (reproductions) "telephone" cells with fahnestock clips.

no. 731 "Big Jim", with terminal studs symmetrically placed in the top.

I've hearde of something simmilar used for "battery C" (grid bias) in valve sets, but IIRC one terminal was a flylead and the other a set of sockets.

For some reason here they were putting pairs of No.6 sized cells at the customer end of the line. I've seen he bakelite housings used.

Yes. A "favorite" for heavy duty flashlights ("bolt" onto the two studs and act like a handle to carry the whole thing)

Dunno. An uncle ran a CO, here. Gave me a really nice annunciator (metal bar suspended beneath a tuned wooden cavity which is then struck by electromagnetically driven rod). It required quite a bit of heft to pull the metal striker up onto the bar (coil was the size of an adult fist). Of course, it ran off CO "battery" which isn't the sort of thing you're likely to have available elsewhere. So, he gave me a couple of these weird "multi-tapped batteries" so I could excite the coil without having a genuine power supply. When the batteries eventually died, I cut them open and discovered all the "D cells" inside.

No idea what they were intended for. I used to use them as a power source when I was a kid (6-8 yo) to "experiment" with electricity. They would run for *hours* (driving trivial loads like low voltage incandescents) without any noticeable sag.

I don't remember them as rechargeable, though (if they were, I don't remember *having* a charger!).