ox THE MECHANICAL PROPERTIES OF STEEL. 103 



" ' This result sho-n-s that a large proportion of phosphorus is extracted by 

 the oxidizing ialiuence of the nitrate, and that a certain amount of the irou 

 is mechanically diifused through the slag. 



" ' The proportion of slag to the yield of crude steel iron was not ascertained 

 by direct experiment; but, calculating from the materials employed, its maxi- 

 mum amount could not have exceeded 23 per cent, of the weight of the charge 

 of molten metal. Consequently tlie 12-6 per cent, of irou in the slag would 

 not be more than 3 per cent, of the iron operated on. 



" ' In conclusion, I have no hesitation in stating that Heaton's process is 

 based upon correct chemical principles ; the mode of attaining the result is 

 both simple and rapid. The nitric acid of the nitrate in this operation imparts 

 oxygen to the impurities always present in cast iron, converting them into 

 compounds which combine with the sodium ; and these are removed with the 

 sodium in the slag. This action of the sodium is one of the peculiar features 

 of the process, and gives it an advantage over the oxidizing methods in com- 

 mon use.' 



"The slag produced is akeady utilized at the works, and forms the subject 

 of a new and valuable patent. There is every reason to believe that the 

 products of combustion may, by the means of a mechanical arrangement, 

 devised by Mr. Heaton, be further utilized and afford a large set-off on the 

 original cost of the nitrate. It is also a great question whether the phosphorus 

 may not be most profitably reduced from the slag for commercial purposes." 



In addition to Mr. Miller's statement, Mr. Robert Mallet reported on the 

 subject and expressed himself highly satisfied with the results, both as regards 

 the chemical and physical properties of the metal ; and having been present 

 at the experiments made on Mr. Kirkaldy's testing machine, he states the 

 results as under : — 



The results recorded in the above Table for cast steel are somewhat 

 below the results obtained in my own experiments, being in the ratio (for 

 the breaking strain) as 41-73 : 44-94, or as -936 : 1, 



The whole of these experiments appears to be correct ; and assuming the 

 statement of cost to be equally satisfactory, we arrive at the conclusion that 

 " taking steel from the furnace in ingots, or made into steel rails, or bar iron, 

 or in any other form of ordinary manufacture, the net cost of production, after 

 adding 10 per cent, for management, including all cost of labour, fuel, and 

 material, and making all allowances for wear and tear and the like, is several 

 jjounds sterling ])er ton imder the present market prices of similar descriptions 

 of the metal." And this will cease to be a matter of surprise when it is 

 taken into consideration that, to repeat the words of Mr. Mallet, " steel can 

 be produced from coarse, low-priced brands of crude pig-irons, rich in phos- 

 phorus and sulphur." " Thus," continues Mr. Mallet, " wrought iron and 

 cast steel of very high quality have been produced from Cleveland and Jforth- 

 amptonshire pig-irons, rich in phosphorus and sulphur ; and every iron- 

 master knows that first-class wrought iron has not previously been produced 

 from pig-iron of either of these districts, nor marketable steel at all." 



