TURE OF CRUCIBLE.
The next great inventions which made for progress in the iron industry were those of Henry Cort (b. 1740; d. 1800), who first made use of grooved rolls in 1784, and in 1785 pro duced the dry puddling process. The invention of puddling was without doubt the foundation of Great Britain's commercial greatness during the century that followed. Prior to this time cast iron had been decarbonized in small hearths, very wasteful of fuel and labor, in which only 100 pounds could be treated at a time. Cort employed the reverberatory type of furnace, in which the metal was not in contact with the fuel, hut was heated by- the flame, which was caused to reverberate, or beat down from the roof of the furnace. This process permitted the use of coal instead of charcoal, and allowed the use of 250- to 500-pound charges. The story of Cort's life is a very sad one, for through a dishonest partner, who died suddenly, his patents were seized to satisfy this partner's liabilities, and Cort died in poverty in 1800. Prominent treasury officials were impli cated in this unjust treatment of Cort. Quite recently Americans have erected a bronze tablet to his memory in the little church in Hamp stead, in the churchyard of which his grave was located with difficulty.
The invention of the hot blast by J. B. Neil son, of Glasgow, in 1828, afforded the next great advance in the metallurgy of iron. In six months the fuel consumption per ton of product was reduced from somewhat over eight tons to a little over five tons, the blast being heated to 300° F. A few years later the blast was heated to 600° F. and the fuel consumption dropped from five and one-sixth to two and one-fourth tons. At the same time there was a great in crease in output as well as decrease in fuel consumption and the production of pig iron in Scotland increased fivefold between 1830 and 1840, while the use of the hot blast became a general practice during that period. As was the case with Cort, so Neilson reaped almost no reward for his invention, although the wealth it conferred upon iron manufacturers could hardly be reckoned. The same was true of
Heath, who in 1840 patented the use of man ganese in steel. This conferred an incalculable benefit upon the manufacturers, but Heath died unrewarded after 15 years of litigation.
It was not until 20 years after the discovery of the value of the hot blast that Sir William Siemens introduced the system of regenerative gas firing—a system in which the waste prod ucts of combustion are employed to heat the incoming gas and air of a as furnace or the blast of a blast furnace. The application of this principle of regenerative heating in the Cowper and Whitwell stoves effected a still further great saving in fuel in the blast fur nace and at the same time increased the yield.
During more than one-half of the last cen tury wrought and cast iron were the only ma terials available for structural and machine con struction, boilers. engines, etc. Crucible steel owing to its high cost could not he used for any of these purposes. Such was the situation when Henry Bessemer gave to the world his wonderful invention. This was the real be ginning of the modern age of steel in which we live. Prior to Bessemer's invention there is .every reason to believe that William Kelly, an American, was working upon what may he called the °pneumatic process.° According to a recent magazine writer, Kelly was experi menting with this process fully 10 years before the date of Bessemer's invention and had built seven stationary converters prior to 1856. His claim of priority of invention was allowed by the United States Patent Office. Nevertheless the process is universally known to-day as the Bessemer process and indeed there can be little doubt hut that Bessemer made an independent discovery of the pneumatic process. Robert Hunt and James M. Swank both agree that for priority of invention William Kelly deserves all praise. See STEEL, THE BESSEMER PROCTSS.