1. A COAL FIRED FURNACE OR THE LIKE HEATING APPARATUS, COMPRISING, IN COMBINATION, A HOUSING; A GRATE SUPPORTED WITHIN SAID HOUSING; A COAL CONTAINER POSITIONED WITHIN SAID HOUSING SUBSTANTIALLY ABOVE AND IN VERTICALLY SPACED RELATION WITH SAID GRATE; MEANS DEFINING A COMBUSTION ZONE ABOVE SAID GRATE, SAID CKJOAL CONTAINER COMMUNICATING WITH SAID COMBUSTION ZONE TO PROVIDE FOR PASSAGE OF COAL FROM SAID CONTAINER INTO THE COMBUSTION ZONE; FLUE GAS DISCHARGE PASSAGE MEANS COMMUNICATING WITH SAID COMBUSTION ZONE ADJACENT THE UPPER END THEREOF AND BELOW SAID COAL CONTAINER; MEANS FORMING AN ADJUSTABLE COMBUSTION AIR INLET OPENING INTO SAID COMBUSTION ZONE; A PLURALITY OF HEAT CONDUCTING VERTICAL PLATES ARRANGED IN HORIZONTALLY SPACED PARALLEL RELATION TO EACH OTHER AND EXTENDING TRANSVERSELY OF SAID GRATE, SAID PLATES BEING POSITIONED IN VERTICALLY SPACED RELATION WITH SAID GRATE AND EXTENDING FROM THE UPPER END OF THE COMBUSTION ZONE INTO SAID COAL CONTAINER; EACH OF SAID PLATES BEING FORMED WITH A DOWNWARDLY OPENING CHANNEL-LIKE MEANS ALONG ITS LOWER EDGE FOR RESTRICTING FLOW OF COAL FROM SAID CONTAINER INTO SAID COMBUSTION ZONE AND FOR ENTRAPPING HOT COMBUSTION GASES OF SAID COMBUSTION ZONE FOR HEATING OF SAID PLATES TO IMPART HEAT TO COAL PASSING THEREBETWEEN FOR DEGASSING OF THE COAL.