ANNEALING METHOD.--Forgings which are too hard to machine are put in pots with a little charcoal to cause a reducing atmosphere and to prevent scale. The covers are then luted on and the pots placed in the furnace. Carbon steel from 15 to 25 points is annealed at 1,600 deg.F. Nickel steel of the same carbon and containing in addition 3-1/2 per cent nickel is annealed at 1,450 deg.F. When the pots are heated through, they are rolled to the yard and allowed to cool. This method of annealing gives the best hardness for quick machining. The requirements in the machine operations are very rigid and, in spite of great care and probably the finest equipment of special machines in the world, a small percentage of the product fails to pass inspection during or at the completion of the machine operations. These pieces, however, are not a loss, for they play an important part in the hardening process, indicating as they do the exact depth of penetration of the carburizing material and the condition of both case and core. HEAT-TREATING DEPARTMENT.--The heat-treating department occupies an L-shaped building. The design is very practical, with the furnace and the floor on the same level so that there is no lifting of heavy pots. Fuel oil is used in all the furnaces and gives highly satisfactory results. The consumption of fuel oil is about 2 gal. per hour per furnace. The work is packed in the pots in a room at the entrance to the heat-treatment building. Before packing, each gear is stamped with a number which is a key to the records of the analysis and complete heat treatment of that particular gear. Should a question at any time arise regarding the treatment of a certain gear, all the necessary information is available if the number on the gear is legible. For instance, date of treatment, furnace, carburizing material, position of the pot in the furnace, position of gear in pot, temperature of furnace and duration of treatment are all tabulated and filed for reference. After marking, all holes and parts which are to remain uncarburized are plugged or luted with a mixture of kaolin and Mellville gravel clay, and the gear is packed in the carburizing material. Bohnite, a commercial carburizing compound is used exclusively at this plant. This does excellent work and is economical. Broadly speaking, the economy of a carburizing compound depends on its lightness. The space not occupied by work must be filled with compound; therefore) other things being equal, a compound weighing 25 lb. would be worth more than twice as much as one weighing 60 lb. per cubic foot. It has been claimed that certain compounds can be used over and over again, but this is only true in a limited way, if good work is required. There is, of course, some carbon in the compound after the first use, but for first-class work, new compound must be used each time.