1. A COMBUSTION INCINERATOR AND HOT WATER HEATER COMPRISING A HOUSING, A FUEL BURNER POSITIONED AT ONE END OF SAID HOUSING WITH ITS FLAME DIRECTED HORIZONTALLY WITHIN SAID HOUSING, A COMBUSTION CHAMBER FOR SAID FLAME, SAID CHAMBER OPEN AT THE TOP AND HAVING AN APERTURE THROUGH THE SIDE THEREOF REMOTE FROM THE BURNER AND ALIGNED WITH THE BURNER FLAME, AN INCINERATOR COMPRISING A GRATE BEYOND SAID COMBUSTION CHAMBER AND WITHIN SAID HOUSING, A DOOR THROUGH A WALL OF THE HOUSING THROUGH WHICH MATERIAL TO BE INCINERATED MAY BE DEPOSITED ON SAID GRATE, SAID GRATE BEING NOT HIGHER THAN SAID APERTURE WHEREBY MATERIAL ON SAID GRATE WILL BE ENGAGED DIRECTLY BY THE FLAME PASSING THROUGH SAID APERTURE THEREBY TO BE IGNITED, A WATER TANK IN SAID HOUSING OF SUCH LENGTH THAT IT EXTENDS OVER SAID COMBUSTION CHAMBER AND GRATE SO THAT HEAT FROM SAID BURNER AND BURNING MATERIAL ON THE GRATE WILL INDIVIDUALLY WHEN IN SOLE OPERATION OR TOGETHER WHEN IN JOINT OPERATION BE DIRECTLY EFFECTIVE TO HEAT THE UNDER SIDE OF SAID TANK, THE END OF SAID TANK ABOVE SAID GRATE BEING SPACED FROM THE ADJACENT WALL OF SAID HOUSING, THE TOP OF SAID TANK BEING SPACED FROM THE TOP OF SAID HOUSING BAFFLES EXTENDING LATERALLY FROM THE SIDES AND OTHER END OF SAID TANK TO THE ADJACENT WALLS OF SAID HOUSING AND A FLUE FROM SAID HOUSING AT THE BURNER END THEREOF AND ABOVE SAID BAFFLES, AND A SCREEN POSITIONED WITHIN SAID HOUSING ABOVE SAID GRATE THROUGH WHICH ALL PRODUCTS OF COMBUSTION FROM THE INCINERATED MATERIAL MUST PASS ON THE WAY TO SAID FLUE, WHEREBY HEAT FROM SAID BURNER AND BURNING MATERIAL WILL BE COMPELLED TO PASS ALONG THE UNDER SIDE OF THE TANK TO THE ENE OPPOSITE THE BURNER, THENCE UPWARDLY AROUND THE TANK END AND HORIZONTALLY ALONG THE UPPER PART OF THE TANK TO THE FLUE.