FURNACES AND PARTS THEREOF, MUFFLES AND PARTS THEREOF, RETORTS AND PARTS THEREOF, LEHRS AND PARTS THEREOF, HEARTHS AND PARTS THEREOF KILNS AND PARTS THEREOF, RECUPERATORS AND PARTS THEREOF, RECUPERATORS AND PARTS THEREOF, REGENERATORS AND PARTS THEREOF, AIR AND GAS HEATERS AND PARTS THEREOF, COMBUSTION CHAMBERS AND PARTS THEREOF, FURNACE ARCHES, FURNACE ROOFS, FURNACE LIDS, FURNACE-ROOF SECTION SHAPES, FURNACE-LID SECTION SHAPES, SECTION SHAPES FOR COMBUSTION CHAMBERS, BLOCKS ADAPTED TO PROVIDE OR FORM COMBUSTION PORTS, FURNACE TUYERES, RECUPERATOR TUBES, RECUPERATOR BLOCKS, REGENERATOR BLOCKS, REFRACTORY CYLINDER SECTIONS, KILN-CAR TOPS, REFRACTORY POTS, RABBLES OF REFRACTORY MATERIAL, REFRACTORY TUBES FOR USE IN FURNACES, PYROMETER PROTECTION TUBES, FURNACE LININGS, FURNACE-LINING BLOCKS, KILN-LINING BLOCKS, CUPOLA BLOCKS, GAS-GENERATOR BLOCKS, AIR-COOLED FURNACE-LINING BLOCKS, SUSPENDED-FURNACE-ARCH BLOCKS, HEARTH-SUPPORT BLOCKS, COMBUSTION TUBES, BURNER BLOCKS, BAFFLE BLOCKS, GLASS TANK BLOCKS, OPEN HEARTH WALL BLOCKS, AIR AND FUEL PORTS AND PARTS THEREOF, CEMENT KILN LININGS, GLASS FEEDERS AND PARTS THEREOF, FURNACE-WALL VENEER BLOCKS-I.E., FACING BLOCKS KEYED, INTERFITTED, OR OTHERWISE SECURED ON A SUPPORTING WALL TO BE PROTECTED, FURNACE-ARCH VENEER BLOCKS-I.E., FACING BLOCKS KEYED, INTERFITTED, OR OTHERWISE CARRIED ON A FURNACE ARCH STRUCTURE TO BE PROTECTED, MUFFLE SECTION SHAPES, RETORT SECTION SHAPES, AND MEANS FOR SURROUNDING OR SUPPORTING WARE IN A KILN AND GENERALLY KNOWN AS KILN FURNITURE