ON THE MECHANICAL PROPERTIES OF STEEL. 99 



wherein consists their superiority as regards deflection, elongation, and com- 

 pression, from all of which may be inferred their nature and properties, and 

 the uses to which they may be applied. It is for this purpose wo have 

 appHed the same formulae of reduction to each particular class of experiments 

 as in the former cases, and the results have been embodied in the summaries. 

 If, for example, it were required to know the modulus of elasticity, the 

 work of deflection, or the unit of working strength, these will be found in 

 their respective columns, carefully deduced from the experiments as given in 

 the Tables. The same principle for ascertaining the amount of work done to 

 produce rupture from tension has been followed, and the force required to 

 produce compression wdth a given load has also been calculated with the 

 same degree of care and attention to facts. 



" As the Bessemer principle of manufacturiug direct from the ore is calcu- 

 lated to jiroduce great improvements and important changes in the produc- 

 tion of refined iron and steel, and as the homogeneous properties of the ma- 

 terial thus produced are of the highest importance as regards security, &c., 

 it is essential to construction that we should be familiar with the mechanical 

 properties of the material in every form and condition to which it may be 

 applied. 



" For this purpose I have given aU the various forms of strain, excepting only 

 that of torsion, which is of less moment, as the strains already described in- 

 volve considerations which apply with some extent to that of torsion, and from 

 which may be inferred the fitness of the material for the construction of shafts 

 and other similar articles to which a twisting strain applies. 



" The great advantage to be derived from the Barrow manufacture of steel 

 is its ductility combined with a tensile breaking strain of from 32 to 40 tons 

 per square inch. With these qualities I am informed that the proprietors are 

 able to meet aU the requirements of a demand to the extent of lOUO to 1200 

 tons of steel i)er week, which, added to a weekly produce of 4500 tons of pig- 

 iron, will enable us to form some idea of the extent of a maniifacture destined 

 in aU probabihty to become one of the most important and one of the largest 

 in Great Britain"*. 



From the above statement it may be inferred that the description of manu- 

 facture practised at Barrow is carried on upon a large scale, and the products 

 have reference to certain properties almost exclusively adapted to the formation 

 of wheel-tyres, rails, and jjlates. To the attainment of these objects the 

 greatest care and attention is devoted by the Company, as may be seen by com- 

 paring the reduction of the experiments in the simimary of results. 



In this extended inquiry I have endeavoured to deduce true and correct results 

 from the specimens with which I have been favoured from the Barrow Steel 

 Company. In the same manner I have now to direct attention to the products 

 of an entirely new system of manufacture introduced by Mr. Heaton of the 

 Langley MiUs, near Nottingham. The experiments on this peculiar manu- 

 facture require a separate introductory notice, as the process of conversion is 

 totally different to that of Bessemer, the Puddling-furuace, or that of the old 

 system of the Charcoal-beds. 



For the finer description of steel the old process of conversion is still prac- 

 tised at Shefiield, from a fortnight to three weeks being required for the con- 

 version of wrought iron into steel ; and, with the exception of Mr. Siemens's 

 Eeverberatory Gas-furnace, there no improvements had been made on it until 



* In round numbers, it is stated tliat the produce of the Barrow Mines is 000,000 tons 

 of ore per annum ; of the Barrow Blast-furnaces 230,000 tons of pig-iron ; and of the 

 Eolling Mills 60,000 tons of steel rails, tyres, plates, &e. 



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