.S7A' WILLIAM \//-;.l//-:.Y\, I-'.R.S. 143 



was discovered by Dr. Werner Siemens in 1853. A further addition 

 of tungsten produces au exceedingly hard metal (introduced into 

 the market by Mr. Mushet in 1808) which cannot be forged, but 

 which when cast into bars, and ground so as to form a sharp edge, 

 produces cutting tools capable of great endurance. 



An admixture of chromium has for many years past been known 

 to produce steel of great hardness and strength, but it is only quite 

 recently that it has been brought into practical use in America by 

 Mr. Julius Baur, and has been taken up in this country by Sir 

 John Brown & Co., of Sheffield, who claim for it very remarkable 

 properties as regards strength, malleability, and freedom from 

 corrosion. 



The formation of compounds such as these is a matter of great 

 interest in connection with the future development of the applica- 

 tions of steel, and is one of those subjects which I venture to 

 suggest might be much advanced by an organized research, under 

 the auspices of a Committee of the Iron and Steel Institute. 



The value of the material known as mild steel or ingot metal, 

 consists in its extreme ductility under all possible conditions. Its 

 ultimate strength is much inferior to that of ordinary steel, and 

 rarely exceeds 28 tons per square inch ; its limit of elasticity is 

 reached at 15 tons per square inch, whilst the limit of elasticity of 

 a harder steel may reach from 25 to 30 tons per square inch, and 

 that of hard-drawn steel wire from 45 to 50 tons. But in esti- 

 mating the relative value of these different materials by the 

 amount of work that has to be expended in causing rupture, it will 

 be found that the mild steel has the advantage over its competitors. 

 When subjected to blows or sudden strains, such as are produced 

 by the explosion of gun-cotton or dynamite, extra mild steel 

 differs in its behaviour from that of BB iron and ordinary steel, 

 by yielding to an extraordinary extent without fracturing, and it 

 is in consequence of this non-liability to rupture that it may be 

 loaded to a point much nearer to its limit of elasticity than would 

 be safe with any other material. 



Attention has been recently directed in various quarters to 

 remedy defects appertaining to steel, viz., piping and showing 

 honey-combed appearance in the ingot. It is well known that if 

 such steel is hammered and rolled, the open spaces contained in it 

 are elongated, and seemingly closed up, but in reality continue to 



