Apparatus for lighting, heating, steam generating, cooking, refrigerating, drying, ventilating, water supply and sanitary purposes; metal melting and holding furnaces (not for experimental use); furnaces and ovens, none for experimental use; boilers (other than parts of machines); industrial crucibles; burners; tubes, shaped linings, cupola syphon blocks, slag-hole blocks, taphole blocks, launders, hot metal pouring chutes, stream dividers, kiln saggars, skimmer blocks, slag notch cooler linings, slag or iron lips, slag notch surrounds, blast furnace troughs, blast furnace sub-hearths, blast furnace trough linings, charging door surrounds, rotar segments, spouts, spout covers, spout burner blocks, spout inserts, orifice rings, flue blocks, burner blocks, stirrer sleeves, damper blocks, channel blocks, arch anchor blocks, arches, arch blocks, stirrers, jamb walls, back and breast walls, shadow walls, port crowns, port openings, overcoat blocks, pyrometer blocks, muffles, industrial retorts and saggars, all for use with the aforesaid furnaces, ovens, boilers and burners; kiln furniture (element supports) of ceramic material; shaped linings and muffles, and pottery kiln furniture; refractory articles, including such articles in brick or block form; goods made of refractory materials for use in heating apparatus, including clay-bonded graphite, carbon-bonded graphite, silicon carbide, or mixtures of the aforesaid materials, for use in the treatment, handling or casting of molten metals or to contain or protect articles during heat treatment; goods for use in heating apparatus made wholly or partially of consolidated aggregates or masses comprising carbon or metal, or carbon and metal.