204 KEPOKT— 1869. 



While science and meclianical skill combine to produce these wondrous results, 

 the germs of furtlier and still greater achievements are matured in our mechanical 

 workshops, in our forg-es, and in our metallurgical smelting works ; it is there that 

 the materials of construction are prepared, refined, and put into such forms as to 

 render greate]- and still greater ends attainable. Here a great revolution of our 

 constructive art has been prepared by the production, in large quantities and at 

 moderate cost, of a material of more than twice the strength of iron, which, instead 

 of being fibrous, has its full strength in every dii'ection, and which can be modu- 

 lated to every degree of ductility, approaching the hardness of the diamond on the 

 one hand, and the proverbial toughness of leather on the other. To call this ma- 

 terial cast steel seems to attribute to it brittleness and uncertainty of temper, which, 

 however, are by no means its necessary characteristics. This new nuiterial, as 

 prepared for constructive purposes, may indeed be both hard and tough, as is illus- 

 trated by the hard steel rope that has so materially contributed to the practical 

 success of steam ploughing. 



Machinery-steel has gradually come into use since about ISoO, when Ivj'upp of 

 Essen commenced to supply large ingots that were shaped into railway tyres, axles, 

 cannon, &c., by melting steel in halls containing hundreds of melting-crucibles. 



The Bessemer process, in dispensing with the process of puddling, and in uti- 

 lizing the carbon contained in the pig-iron to effect the fusion of the final metal, 

 has given a vast extension to the application of cast steel for railway bars, &c. 



This process is limited, however, in its application to superior brands of pig-iron, 

 containing much carbon and no sulphur or phosphorus, which latter impurities are 

 so destructive to the quality of steel. The puddling process will still have to be 

 resorted to, unless the process of decarburization proposed by Mr. Ileaton should 

 be able to compete with it, to purify these inferior pig-irons which constitute the 

 bulk of our productions, and the puddled iron cannot be brought to the condition 

 of cast steel except through the process of fusion. This fusion is accomplished 

 successfully in masses of from three to five tons on the open bed of a regenerative 

 gas furnace at the Landore Siemens-Steel "Works and at other places. At the same 

 works cast steel is also produced, to a limited extent as yet, from iron ore which, 

 being operated upon in large masses, is reduced to the metallic state and liquified 

 by the aid of a certain proportion of pig metal. The regenerative gas furnace, the 

 application of which to glass-houses, to forges, iSrc, has made considerable progress, 

 is unquestionably well suited for their operations, because it combines an intensity 

 of heat limited only by the point of fusion of the most refractory material, with 

 extreme mildness of draught and chemical neutrality of flame. 



These and other processes of recent origin tend towards the production at a com- 

 paratively cheap rate of a very high-class material that must shortly supersede iron 

 for almost all structural puiijoses. As yet engineers hesitate, and very properly so, 

 to construct their bridges, their vessels, and their rolling-stock[of the'materiarpro- 

 duced by these processes, becau.se no exhaustive experiments have been published 

 as yet fixing the limit to which they may safely be loaded in extension, in com- 

 pression, and in torsion, and because no sufficient information has been obtained 

 regarding the tests by which their quality can best be ascertained. 



This great want is in a fair way of being supplied by the experimental researches 

 that have been carried on for some time at Her Majesty's Dockyard at AVoolwich 

 under a committee appointed for that purpose by tlie Institute of Civil Engineers. 

 In the mean time excellent service has been rendered by Mr. Kirkaldy in giving 

 us, in a perfectly reliable manner, the resisting-power and ductility of any sample 

 of material which we wish to submit to his tests. 



The residts of Mr. '\\ liitworth's experiments, tending to render the hammer and 

 the rolls partly mmecessary, by consolidating cast steef while in a semifiuid state, 

 in strong iron moulds, by hydraulic pressure, are looked upon with general interest. 



But, assuming that the new material has been reduced to the utmost degi-ee of 

 uniformity and cheapness, and that its limits of strength are fidly ascertained, 

 there remains still the task for the ci^ il and mechanical engineer to-prepare designs 

 suitable for the development of its peculiar qualities. If, in constructing a girder, 

 for example, a design were to be adopted that had been worked out for iron, and 

 if all the scantlings were simply reduced in the inverse proportion of the absolute 



