The Historic District

This is a cast iron box mounted in the walk-in pantry wall. (Not the butler's pantry)The top vents into the fireplace chimney. We think maybe it was used to hold hot coals so you could let the oven cool down over the heat of the day and not have to start your fire from scratch. Does anyone else have one of these and what are they called?

Looks like a clean-out of some kind

They guy why came to inspect/clean our fireplaces/chimneys said that he had never seen one.
Pretty much all he does are houses over 75 years old. He was sure it had something to do with the kitchen.

Clarification- the door is cast iron, the inside is fire brick.

I'm with Mick - it looks like some kind of cleanout. It's too small to be a trash incinerator or anything like that and I don't think anyone in their right mind would carry hot coals through a house. What's on the other side of the chimney and directly above it on the next level of the house?

Just a long shot, could it be for warming the chimney to get the draft going before lighting the main fire places. The first up in the morning would light a small fire in there.

It is right behind the main floor fireplace. Above it is the servants stairs to upstairs. It is just a few feet from where the wood stove would have been, which is why we thought it might have to do with the stove. The fireplace guy was very surprised at the construction of our chimneys, they are lined with clay tile. According to him, that was not common around here for another 15-20 years. This house has all kinds of stuff ahead of it's time though. (Like fire hoses and its own generator) It was built by the richest dude in the county. Too bad it didn't rub off on the current owners.

Is it large enough to have been used for baking? Maybe like a bread oven since its right next to the kitchen? Holding hot coals seems to fit right - how old is your house?

Not nearly big enough for an oven. House was built 1907. My husband is pretty sure a fire was actually built in the box. Maybe they kept a small fire in there so they did not have to start a fresh one in the morning.

it's a secret door to dump the bodies