HKB
to me that much of this could be avoided by employing some other means for getting rid of the superfluous carbon, and bringing the molten cast-iron into a malleable condition.
The method that occurred to me was the substitution of a small steam pipe in the place of the puddler's rabbling bar. By having the end of this steam pipe bent downwards so as to reach the bottom of the pool, and then to discharge a current of steam beneath the surface of the molten cast iron, I thought that I should by this simple means supply a most effective carbon-oxidating agent, at the same time that I produced a powerful agitating action within the pool. Thus the steam would be decomposed and supply oxygen to the carbon of the cast-iron, while the mechanical action of the rush of steam upwards would cause so violent a commotion throughout the pool of melted iron as to exceed the utmost efforts of the labour of the puddler. All the gases would pass up the chimney of the puddling furnace, and the puddler would not be subject to their influence. Such was the method specified in my patent of l854* [footnote... Specification of James Nasmyth--Employment of steam in the process of puddling iron. May 4, 1854; No. 1001. ...]
My friend, Thomas Lever Rushton, proprietor of the Bolton Ironworks, was so much impressed with the soundness of the principle, as well as with the great simplicity of carrying the invention into practical effect, that he urged me to secure the patent, and he soon after gave me the opportunity of trying the process at his works. The results were most encouraging. There was a great saving of labour and time compared with the old puddling process; and the malleable iron produced was found to be of the highest order as regarded strength, toughness, and purity. My process was soon after adopted by several iron manufacturers with equally favourable results. Such, however, was the energy of the steam, that unless the workmen were most careful to regulate its force and the duration of its action, the waste of iron by undue oxidation was such as in a great measure to neutralise its commercial gain as regarded the superior value of the malleable iron thus produced.
Before I had time or opportunity to remove this commercial difficulty, Mr. Bessemer had secured his patent of the l7th of October, 1855. By this patent he employed a blast of air to do the same work as I had proposed to accomplish by means of a blast of steam, forced up beneath the surface of the molten cast iron. He added some other improvements, with that happy fertility of invention which has always characterised him. The results were so magnificently successful as to totally eclipse my process, and to cast it comparatively into the shade. At the same time I may say that I was in a measure the pioneer of his invention, that I initiated a new system, and led to one of the most important improvements in the manufacture of iron and steel that has ever been given to the world.