Meanwhile the converter which we saw emptied has not been idle. The American steel engineer has genius for mechanical efficiency and all parts of a great steel plant are so co-ordinated that enormous quantities of material can be handled with not a moment lost between trips. Almost before the ladle of steel had swung away from the converter’s mouth, any remaining slag was dumped from the converter by further tipping, the vessel returned to receiving position and the ladle car, back again from the mixer, poured in the next charge. Thus blow after blow is made without loss of time. Repairs are allowed to take no longer than is absolutely necessary. When the lining around the tuyères gets too badly cut by the action of the air and metal the bottom is removed, another one is quickly substituted and the steel making goes on. Blowers, ladlemen, cranemen, pourers, patchers, vesselmen, sample boys and the other workmen are relieved by their “partners” at the end of each shift, each man of necessity working until relieved—twelve, twenty-four, or even thirty-six hours, for there must be no delay. So day and night, through the entire week from Monday morning at six, when they begin, until the next Sunday morning at six, when the plant shuts down for a brief spell, the converters go on turning out three heats per hour or four to five hundred per week each. It has been mentioned that most of Bessemer’s first licensees failed with the new process. The reasons for this were various, but one in particular was the attempt of many to use metal of high phosphorus content. Bessemer soon discovered that no phosphorus was removed during the “blow” and that, as phosphorus in quantity over one-tenth of one per cent was detrimental to steel, it was necessary to use raw material which had little of this element. This could be done, but it barred many pig irons otherwise good. Fortunately Swedish and many English irons had low phosphorus. Germany’s vast beds of high phosphorus ores, however, were useless for the purpose. For twenty years this situation existed, during which time many metallurgists endeavored to make the process applicable to irons which contained high phosphorus. After long study and many experiments the problem was solved by Sidney Thomas, an English metallurgist. With a cousin, Percy Gilchrist, he made hundreds of blows with a toy converter holding only eight pounds of iron. Bessemer’s linings had been of sand, clay and other earths which are known chemically as “acid” materials. By using “basic” materials such as limestone, dolomite, etc., for the converter lining and additions of limestone or burnt lime to the charge before and during the blow to make and keep the slag “basic,” Thomas was able to make the phosphorus burn after the carbon had been removed. Therefore, a three or four minute “after blow” following the “drop” of the carbon flame took out the phosphorus,—again, with generation of heat.