Unique best Unusual ANTIQUE copper pot - two layers - primitive Vacuum

IF YOU CAN IDENTIFY THIS GADGET PIECE PLEASE LET ME KNOW - I think it is an early vacuum flask effect vessel or liquid warmer but not sure
It is a tea pot shaped really old copper pot with a pull out lid with a small copper loop on, it also has a pipe like structure that has a small screw on cap, this leads to the inner layer of the pot, the pot has two layers, I think to keep something warm, like an early vacuum. It has a Bakelite handle and a pointed spout which is a bit damaged.
It is 10 inches spout to handle tip and just under 6 inches tall.
It really is old- the distance when measuring on the outside is different to that when measure on the inside. best