132,262. Basset, L. P. Sept. 3, 1918, [Convention date]. Rotary furnaces.-A furnace for use in the production of iron or steel consists of a long inclined body a having at its lower end an enlarged chamber b into which a mixture of air and finelydivided carbon is projected in such proportions that an atmosphere of carbon monoxide is produced in the furnace. In the construction shown finely-divided carbon from a hopper h is blown into the furnace by air from a blast pipe g. Tap. holes j, k for metal and slag respectively are provided in the end of the chamber b. In operation, the ore, preferably finely crushed, is fed to the furnace by the conveyer n, and, after reduction has been effected in the body portion a, the metal and slag collect in the chamber b. The slag overflows through the holes k, and the metal may be tapped for further treatment in another furnace. Alternatively, the refining may be effected in the chamber b by adding first an oxidizing and basic slag for the removal of carbon, silicon, manganese, and phosphorus, and after. wards a highly basic reducing-slag for the removal of sulphur. The air blast may be heated by combustion of a portion of the furnace gases. Specification 158,523 is referred to. In the Specification as open to inspection under Sect. 91 (3) (a) it is stated that a hydrocarbon may be used as the heating-agent. This statement does not appear in the Specification as accepted.