is that a chain draped across it? the really cool ones had a system of pulleys, long chain and a lever system in the kitchen that would connect to the air shutter.. in the coal days you could control the draft/fire/temperature all from the comfort of the kitchen!
in any old house, keep an eye out for little pulleys on the joists. cool stuff
and yes, comfortable. " we dont need no stinking 35 deg td efficiency" try 130 deg temp rise! as 200 deg was the usual limit setting