Antique spirit burner or alcohol burner. The burner was almost certainly originally used in a stand for a spirit tea kettle or possibly in a similar stand for a chafing pot. I have also seen similar ones used in desk sets for melting sealing wax in a small pan though I believe that is less likely in this case. There may have been a snuffer attached at some point – this is a small hinged pan attached to a ring that sits between the screw lid and the base so it could easily have become detached at some point assuming it was ever there.
The burner is untested but I believe it to be working. I have not cleaned it at all and it has a great patina. It stands 6 cm tall and measures 12.5 cm across its widest point.