This is a Thermatic fireless cooker manifactured by The Diller MFG Co. Patented Nov. 17, 1914 and 1915. The fireless cooker was designed in the early 1900 to save the women precious time from cooking all day in preparing a meal for the end of the day. It was basicaly designed as we see a crock pot today. It cooked without fire and provided an effortless hot meal at the end of the day. Soup, stew or porridge could be half cooked during the morning and than placed in the cooker. During this time the food would continue to cook from it's own residual heat and be ready to eat in a few hours. They also had soapstone plates that were heated up and placed inside to cook unheated food. If you search the internet you can find more information on the stoves.