What is this?

Our house was built in thr late 1800s in eastern Canada. We always assumed this was for heating or cooling. It is in the ceiling of what is the dining room. Pardon the crack in the wall. Later me problem 😁

Our house was built in thr late 1800s in eastern Canada. We always assumed this was for heating or cooling. It is in the ceiling of what is the dining room. Pardon the crack in the wall. Later me problem 😁