WILLIAM SIEMENS, F.R.S. 465 



paper. As an official referee of Lloyd's it would have 

 been much easier for Mr. Parker to continue on the old lines, 

 which would have saved him a great deal of trouble and a great 

 deal of responsibility ; and he (Sir William Siemens) thought it 

 was a most welcome thing to find a gentleman in Mr. Parker's 

 position corning forward and asserting the advantages in favour of 

 a new mode of practice. There could be no doubt that a steel 

 casting, if made without blow-holes, and if properly annealed, was 

 more reliable than a forging, if the form was at all of a compli- 

 cated kind. It had already been shown to them in forgings of 

 large shafts, and especially where a large shaft was suddenly con- 

 tracted down to a narrow throat or changed its direction in 

 order to form a crank, that the act of forging was productive 

 of a very great evil. A blow could not be struck sufficient 

 to penetrate the whole of the mass, and a light blow must 

 necessarily have the effect of extending the surface and thereby 

 producing cavities in the interior where strength was wanted. 

 On the other hand, if a casting be cooled in the mould, it must 

 contract unequally, and must have within itself the germs of 

 destruction ; and it must therefore be most advantageous to cool 

 it right down, whereby these differences of tension would be 

 brought to a maximum and very likely cause an evil that was 

 preventable. In order to anneal the casting to the best advan- 

 tage, it should be removed from the mould to the annealing stove 

 without allowing it to cool ; they would thus give time for the 

 different parts, while at a uniform temperature, to adjust them- 

 selves to one another. 



Oil hardening had been alluded to, and very remarkable results 

 had been obtained through it which had never been satisfactorily 

 explained. Why steel should be increased in its ultimate strength 

 without losing its ductility was a matter requiring further investi- 

 gation. The oil did not seem to enter chemically into the process 

 at all ; the result could only be due to that degree of surface 

 cooling, which, while it did not amount to cracking or injuring 

 the surface of the metal, produced the effect of compression on 

 the inner portions of it, a compression which they knew was 

 favourable to a dense structure of the metal such as they found 

 suited best for resisting great strains. Nor could he agree quite 



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