This is a cast iron glue pot. They came with an outer pot for water and an inner pot for the glue.
They acted like a "double boiler", in order to gently heat up the glue without direct heat.
In a previous post, I said there were no cast iron double boilers, and there aren't any on the market today. But there used to be glue pots.
Before Elmer's glue, there was "hide glue" made from animal skin and bones. This glue had to be heated before it could be used, and it was heated on the stovetop, in a glue pot.
Hide glue is still used today in woodworking, but the glue pots are usually electric.