1869.] on the Mechanical Properties of Steel. 23 



quality, as everything depends on tlie skill of tlie operator in closing 

 the furnace at the precise moment of time, before the mass is 

 deprived of its carbon. This precaution is necessary in order to 

 retain the exact quantity of carbon in the puddled bulb, so as to 

 produce by combination the requisite quality of steel. It will be 

 observed that in the Bessemer process this uncertainty does not 

 exist, as the whole of the carbon is volatilized or burnt out in the 

 first instance; and by poming into the vessel a certain quantity 

 of crude metal containing carbon, any percentage of that element 

 may be obtained in combination with the iron, possessing qualities 

 best adapted to the varied forms of construction to which it may 

 be applied. Thus the Bessemer process is not only more j)erfect 

 in itself, but admits of a greater degree of certainty in the results 

 than could possibly be attained by the mere employment of the 

 eyes and hands of the most experienced puddler. Thus it aj^pears 

 that the Bessemer process enables us to manufacture steel with 

 any given proportion of carbon, or other eligible element, and 

 thus to describe the compound metal in terms of its chemical 

 constituents. 



Important changes have been made since Mr. Bessemer first 

 announced his new principle of conversion, and the results obtained 

 from various quarters bid fair to establish a new epoch in metallurgic 

 manipulation, by the production of a material of much greater 

 general value than that which was produced by the old process, 

 and in most cases of double the strength of iron. 



These imj^rovements are not exclusively confined to the Bessemer 

 process, for a great variety of processes are now in operation pro- 

 ducing the same results, and hence we have now in the market 

 homogeneous and every other description of iron, inclusive of steel, 

 of such density, ductility, &c., as to meet all the requirements of the 

 varied forms of construction. 



The chemical properties of these different kinds of steel have 

 been satisfactorily established ; but we have no rehable knowledge 

 of the mechanical properties of the different descriptions of homo- 

 geneous iron and steel that are now being produced. To supply this 

 desideratum, I have endeavoured, by a series of elaborate experiments, 

 to determine the comparative values of the different kinds of steel, 

 as regards their powers of resistance to transverse, tensile, and 

 compressive strain. 



These experiments have been instituted not only for those 

 engaged in the constructive arts, but also to enable the engineer to 

 make selections of the material as will best suit his purpose in any 

 work proposed. In order to arrive at correct results I have 

 applied to the first houses for the specimens experimented upon, and 

 judgitig from the results of these experiments, I venture to hope 

 that new and important data have been obtained, which may safely 



