Among the steels, those that are softer are more serviceable and reliable than the harder ones, especially whereever shocks and concussions or rapidly alternating strains are to be endured. In other words, the more nearly steel resembles good wrought iron, the more certain it is to render lasting service when used within appropriate limits of strain. Indeed, a wrought iron of fine quality is better calculated to endure fatigue than any steel. This is particularly noticeable in steam hammer pistons, propeller shafts, and railroad axles. A better quality of wrought iron, therefore, has long been a desideratum, and it appears now that it has at last been found. Several years since, a pneumatic process of manufacturing wrought iron was invented and patented by Dr. Chapin, and an experimental plant was erected near Chicago. Enough was done to demonstrate, first, that an iron of unprecedentedly good qualities was attainable from common pig; and second, that the cost of its manufacture would not exceed that of Bessemer steel. Nevertheless, owing to lack of funds properly to push the invention against the jealous opposition which it encountered, the enterprise came to a halt until quite recently, when its merits found a champion in Gustav Lindenthal, C.E., member of this club, who is now the general manager of the Chapin Pneumatic Iron Co., and under whose direction this new quality of iron will soon be put upon the market. The process of manufacture is briefly as follows: The pig metal, after being melted in a cupola and tapped into a discharging ladle, is delivered into a Bessemer converter, in which the metal is largely relieved of its silicon, sulphur, carbon, etc., by the ordinary pneumatic process. At the end of the blow the converter is turned down and its contents discharged into a traveling ladle, and quickly delivered to machines called ballers, which are rotary reverberatory furnaces, each revolving on a horizontal axis. In the baller the iron is very soon made into a ball without manual aid. It is then lifted out by means of a suspended fork and carried to a Winslow squeezer, where the ball is reduced to a roll twelve inches in diameter. Thence it is taken to a furnace for a wash heat, and finally to the muck train. No reagents are employed, as in steel making or ordinary iron puddling. The high heat of the metal is sufficient to preserve its fluidity during its transit from the converter to the baller; and the cinder from the blow is kept in the ladle.