MECHANICS AND USEFUL ARTS. 27 



which may be supplied at 13 per ton. The tensile strength of the 

 Bessemer steel is great, and the metal is now obtained of very uniform 

 quality. Out of twenty-eight pieces taken at random in one estab- 

 lishment, the extreme of difference in tensile strength was about 

 five pounds or so. Mr. Bessemer also exhibited a twenty-four 

 pounder gun in the rough,- and another of the same rate in the fin- 

 ished state. That in the rough is a solid forging of Bessemer steel, 

 forged from an ingot eighteen inches square, and weighing twenty- 

 eight hundred-weight. It was stated that the material of which 

 these guns were composed possessed nearly double the strength of 

 the best " Low-moor" iron, and that their cost was less than wrought 

 iron in the same shape. Steel was also shown in the Exhibition 

 produced by the so-called process of " Ucliatius" which consists in 

 melting together granulated pig iron and oxide of iron, when the car- 

 bon of the former is more or less burnt out at the expense of the 

 oxygen of the latter, with a corresponding reduction of iron. The 

 proportions should be so regulated that sufficient carbon may be left 

 to form steel. This process, which excited much attention a few 

 years ago, has not, as yet, come into extensive use, it is said for two 

 reasons : First, the difficulty of obtaining uniform results ; and, 

 secondly, the high cost. 



There was also shown, in the British and Swedish departments, 

 steel produced by melting together charcoal, pig iron, and scrap 

 wrought iron. Here the product retains the whole of the carbon, and 

 the relative amounts of the ingredients used must be such as to pro- 

 duce steel. It is requisite for this purpose that the pig iron should be 

 of good quality. The reader should bear in mind that all steel, by 

 whatever process it may have been produced, is termed cast steel 

 after having been melted. The variations in quality of the different 

 kinds of steel in commerce are innumerable, and in many cases the 

 reasons for such variation are quite unknown. They are undoubtedly 

 chemical, but have hitherto bafHed the efforts of chemists to detect 

 them. Much attention has, however, of late been directed to this 

 most interesting subject, and there is now some hope that we shall 

 not much longer remain in our present state of ignorance concern- 

 ing it. 



In the Austrian department, specimens of the so-called " wolfram " 

 steel were shown, made by melting together cast steel and the mineral 

 wolfram, by which addition it is believed the quality is greatly im- 

 proved. Steel thus produced breaks with a very fine grain, and is 

 hard and tough ; but we have learned, on excellent authority, that this 

 alloy has not been found practically successful. 



Much has been said of late respecting the value of titanium and 

 other elements in steel ; but we learn that the best practical authori- 

 ties in England do not as yet consider that any satisfactory evidence 

 of the good effects of the presence of such foreign matters in steel has 

 been presented. 



Krupp's Cast Steel. But one of the most extraordinary and most 

 important collections of the Exhibition, and one the like of which 

 has never before been witnessed, was a display of cast steel made by 

 Mr. Krupp, of Essen, Germany. The special points of interest about 

 this manufacturer's exhibit are the wonderful soundness and the enor- 



