One of the guys on Amertrac's favorite chat line has this item he bought. Is it a hanger for kettles so that different ones can be placed over the fire?

It could be.  Some of the old cast iron pots didn't have bales, but knobs cast near the rim.  I've seen something like this -- back when I was working at Sutter's Fort -- but I can't recall it well now.  Might have been in one of Eric Sloane's books.

I think, though, it wasn't for hanging so much, but for lifting.  Another thing about old kitchen cast iron was that the pots often had feet or legs so they could stand in the embers of the hearth.  Posnets (essentially what we call sauce pans) had three legs as part of the casting, and so did a lot of Dutch ovens.

I think there's another use for things like this, but it just escapes me now.  I think similar hooks were used for lifting bales, and for weighing them on a beam scale.  Too many brain cobwebs at the moment.

Yes, I think that is what it is.  I have had several of them.  Sometimes the hooks go in opposite directions.  I think they are called pothooks.

That's it, John! Can't think why I didn't think of that.