Cog tooth spacing on old gears.

I'm looking at an old, single-cog US made hub. From tip to tip of the
teeth is measuring about 9/16", as closely as I can measure, anyway.
It's just a tad bit longer than the modern chain, such that it'll span
about three teeth, but no more.

So, what kind of chain and chain ring is it for which I'm searching?
If I knew what to call it, I'd be more likely to find it.

Jones