144 THE ADDRESSES, LECTURES, ETC., OF 



form severances within the metallic mass, to the prejudice of the 

 uniform strength of the finished forging. 



In casting steel containing more than *5 per cent, of carbon, 

 the defect of honey-combing can easily be avoided if care is taken 

 to have the metal "dead melted" before pouring it into the 

 mould ; and that of piping by continuing the inflow of fluid 

 metal for a sufficient length of time while it is setting. But in 

 dealing with mild steel containing only say *2 per cent, of carbon, 

 the difficulty of making a sound casting is greatly increased. 

 Much may be done, however, by careful manipulation of the fluid 

 metal, and by the judicious addition to it of manganese or other 

 oxidizable metals, such as silicon or lead, by which occluded 

 oxygen is removed. 



Sir Joseph "Whitworth, who, as you well know, has given much 

 attention to this subject, has overcome the evil mechanically by 

 subjecting the steel, while setting in the mould, to great hydraulic 

 compression. He has thus succeeded in producing, in large masses, 

 mild steel of extremely uniform strength, and the only doubt 

 which could possibly be raised against the advisability of pro- 

 ducing steel for ordinary applications by this method is founded 

 on considerations of cost. 



The subject of producing sound steel castings is one which we 

 shall have an opportunity to discuss in reference to a paper which 

 will be presented by M. Gautier. 



APPLICATIONS OF STEEL. The employment of steel for general 

 engineering purposes dates only from the year 1851, when Krupp, 

 of Essen, astonished the world by his exhibits of a steel ingot 

 weighing 2,500 Ibs., and of his first steel gun, and introduced a 

 comparatively mild description of pot steel for steel tyres, axles, 

 and crank shafts. For the production of these he constructed his 

 celebrated monster hammer, with a falling weight of 45 tons, 

 which, at that time, far surpassed in magnitude and power our 

 boldest conception, and is now only being exceeded by a still more 

 powerful hammer in course of erection at the Essen Works. 

 Krupp's steel was, however, not cheap steel, and it is to our past 

 president, Mr. Henry Bessemer, and to the important addition 

 made to his process by Mr. Mushet, that we are indebted for the 

 production of steel at such a reduced cost as to make it available 

 for railway bars and structural purposes in substitution for iron, 



