Antique chamber stove (gasless)

I pick up this cool chamber stove. What I read about it is. It is a stove they call gasless. You can is the Thermodome. My understanding is you begin cooking with has which also heats the water in the Thermodome, once that is hot you would shut of gas and the steam from the Thermodome will finish cooking foot, thus gasless. Please if I'm not correct let me know.