This is a very unusual item. It appears from the Victorian era.
This is what is called a boat, the container for incense that a priest blessed and then with a spoon places incense resin granules on hot coals in the censor or thurible used in Christian worship.

It is solid brass and heavy. It is very intricately detailed with ornate scrolly engravings on the top, sides and base. The top of it where the lid lifts up also has a Cherub with wings. It has a lid that does not close all the way - meant to be this way - since the small openings at the side of the lid would allow incense to stay lit and the smoke to escape. It is heavy and solid. The inside does look like it had incense burning in there. There is some discoloration and staining inside. The outside of the piece is in fine condition with a nice natural aged patina. It measures 3 1/8" tall, 5 1/2" long and 2 3/4" wide. So neat!!