TRANSACTIONS OF SECTION G. 497 



am sure the audience will in their minds anticipate the record of the name of 

 Bessemer — a name which -will be handed down to posterity in connection with the 

 manufacture of steel as long as that manufacture exists. 



Another name which will most deservedly figure in the history of the develop- 

 ment of the steel manufacture is one, like that of Bessemer, which has been known 

 not only in that development, but in connection with many other discoveries in 

 physical science — I mean that of Siemens, who, like his compeer, has not only 

 invented processes, but has personally carried them out into practical application. 

 An expression let fall by the latter as President of the Iron and Steel Institute at 

 its meeting last year in Paris, exhibits very strikingly the absence of any other 

 feeling on the part of these two great men save that of the most friendly rivalry. 



Speaking of a comparison between the results of steel manufactured by the 

 Bessemer blowing process and the Siemens-Martin open-hearth process, Dr. Siemens 

 said, ' He did not see how the result could be the same. It might be better in the 

 Bessemer process than in the open-hearth for aught he knew, but it could not be 

 the same ;' and it seems to augur well for the advancement of science in our day 

 that so little of a contrary spirit is exhibited in the discussions which ensue from 

 time to time upon any improved process either chemical or mechanical, having for 

 its object the production of a better material and at a lower first cost. The name of 

 Robert Mushet may very properly be introduced here as one of our early inventors 

 of the improved processes for the manufacture of steel, and it is gratifying to find 

 that other countries besides England have learnt to appreciate the results obtained 

 by him during so many years of scientific and experimental research. 



It is needless that I should do more in an assembly like that before me than 

 refer in the simplest terms to the differences in the processes of manufacture con- 

 nected with these names. 



In that of Bessemer, pig-iron of a selected quality is charged into what is 

 technically called a ' Converter,' a large iron vessel lined with refractory material, 

 into which air can be blown at considerable velocity by suitable blowing machinery. 

 This goes on until the iron is thoroughly exposed to the decarbonising influence of 

 the blast, and the impurities contained in the metal are driven off. When this 

 happens the blowing ceases, and a certain proportion of Spiegel eisen or of ferro- 

 nianganese is added to the charge so as to give the required amount of carbon. 

 Blowing recommences, this time only to effect complete mixture of the materials, 

 and then the casting of the ingots takes place of a quality corresponding to the 

 metal selected for the mixtures. A mild steel — or, as it has been called, a pure 

 iron— is the resultant, and it is capable of being worked, welded, and hammered 

 very much as iu the case of the purest wrought irons ; but it possesses generally 

 a much higher tensile resistance and a greater ductility. 



In the Siemens-Martin or open-hearth process, a similar charge of pig-iron of 

 the desired quality— probably haematite pig — is put into the bed of a reverberatory 

 furnace of the regenerative system, and the necessary oxidation is produced by 

 adding to the molten mass iron ores, or oxides of iron in proportions ascertained by 

 experience, after which re-carbonisation is obtained by the addition of ferro-rnan- 

 ganese or Spiegel eisen as in the Bessemer process. 



These processes have been the great factors in that reduction in the cost price, 

 and therefore in the extension of the use of such objects as steel tyres, axles, shafts, 

 rails, &c, to which I have already referred, and which is so striking an instance of 

 the results which our men of science can accomplish by their physical and experi- 

 mental researches into the means of supplying the wants of our work-a-day 

 world. 



I will now draw attention to another product of the steel manufacture which 

 is of immense importance, and which could not have been obtained for ordinary 

 purposes but for the facilities of manufacture arising out of the inventions I have 

 just alluded to — I mean that of steel castings, i.e., castings obtained from the 

 crucible, precisely in the form in which they are to be used in the construction of 

 machinery, just as is the case in ordinary cast iron run from the cupola furnace. 

 This production of castings for engineering purposes is gaining an enormous and 

 rapid development ; and when it is considered thati n this metal we obtain castings 



1879. K K 



