34 STEAM AND HOT WATER BOILERS, WATER HEATERS, TANK CAR HEATERS, COMBINATION TANK CAR HEATING AND PUMPING APPARATUS, EVAPORATORS, STILLS FOR PRODUCING PURE WATER FROM IMPURE WATER, OIL BURNING HEATERS FOR BITUMINOUS AND LIKE MATERIALS, AND CONVERSION OIL AND GAS BURNERS, AND PARTS THEREOF