SCIENTIFIC METALLURGY AND MINING. II3 



nation, the fact that lie had discovered a new method of producing steel 

 direct from pig iron. The general practice to produce steel at this time 

 was first by converting pig iron into wrought iron, and then by a slow 

 and expensive process to change wrought iron into steel. This was a 

 very circuitous way of ultimately making steel, for steel, speaking 

 roughly, is intermediate in comparison with pig iron on the one hand 

 and wrought iron on the other. The old process is something analagous 

 to the action of the man who wishes to travel from Dunedin to Welling- 

 ton, and who, to faciltate matters, goes first to Auckland. Bessemer saw 

 this very clearly, and not only this, but the fact that steel could not be 

 applied to many ordinary purposes unless some other process were 

 invented. To convei"t pig into wrought iron a puddling furnace is 

 used. In this furnace the iron is melted and exposed for a considerable 

 time to the oxygen of the atmosphere and to the influence of a special 

 furnace lining composed of oxide of iron, by this means the various 

 impurities in the iron are burnt out. In this process considerable fuel 

 is used to keep the iron in a molten state. With characteristic boldness 

 BesBemer said in effect, why should not the heat given out in burning 

 these impurities be used for keeping the iron in a molten state. If 

 instead of passing the air over the surface of the metal, it could be 

 urged through the metal so that the oxygen could come into contact 

 with every particle almost simultaneously, then the process that now 

 requires considerable labour and time could be completed much more 

 efficaciously in a few minutes and with very little labour. For boldness 

 of conception such a suggestion has perhaps never been equalled in the 

 metallurgical art. The thought of urging air through tons of molten 

 iron was rash enough to frighten the most courageous of iron smelters. 

 How will the iron be kept molten, how will you prevent the burning of 

 the iron and its consequent utter deterioration I Bessemer heeded not 

 these gloomy forebodings, but for 15 years worked at his great 

 invention, and ultimately overcame those enormous mechanical diffi- 

 culties which beset every proposed change in the treatment of large 

 masses of metal, and particularly so, when that metal has a high 

 melting point. The effects of this invention upon the steel industry 

 were simply marvellous. Steel at this time was selling at mor - e than 

 £50 per ton, and could only be obtained in small quantities. The price 

 has since fallen to £10 per ton, and the increase in its use is most 

 extraordinary. There is perhaps no article of commerce the use of 

 which has inci-eased so rapidly. It is said that at the time of this 

 invention, 51,000 tons of steel were produced annually in Sheffield. 

 Now the production has to be estimated by millions of tons. Steel is 

 thus rapidly replacing cast and wrought iron for all conditions where 

 strength and homogeneity are required. It would require a considerable 

 length of time to enumerate the many ways in which this invention has 

 benefited the engineering profession. How it has given to them greater 

 possibilities, and a much wider field for their ingenuity I will merely 

 mention one that you are all familiar with. The Forth bridge may, 

 perhaps be regarded as one of the finest structures erected during this 

 century, and one of which Scotland may justly be proud. I am not 

 overstepping the mark, indeed, I am only repeating the words of a 

 great authority on this subject, when I say that it could never have 

 been built if the inventions of Bessemer, and of his equally famous 



