376 THE SCIENTIFIC PAPERS OF 



and sulphur in the final result, because taking the half of nothing, 

 it was again nothing. But if they had an impure pig metal to 

 deal with, the simple diminution in weight must, as it was well 

 known it did, increase the percentage of phosphorus and sulphur 

 in the Bessemer metal, whereas the ore in acting upon the bath 

 not only substituted for every pound of carbon and silicon it took 

 away a pound of pure iron, but the slag took away at least a small 

 portion of the impurities from the metal, especially if lime were 

 used in the process. One of the essential differences between the 

 two metals was this (and it was well known in practice at those 

 works where the open-hearth furnace was carried on), that if they 

 wanted a certain ductility, they must put T Vth per cent, more 

 carbon into the open-hearth metal than they would require in the 

 Bessemer metal. That was common practice. It was alluded to 

 in Mr. Akerman's paper, but with a doubt thrown upon it. He 

 could inform them that it was a positive fact, and it was a signifi- 

 cant fact also ; because if for the attainment of a certain degree 

 of ductility they could put in T Vth per cent, more carbon, it meant 

 that they had the extra strength due to the -j^th per cent, of 

 carbon in their metal, and for that reason he believed that the 

 open -hearth metal would have its own special application, in 

 which it would take the first position, whereas the Bessemer metal 

 was very excellent indeed for perhaps the majority of purposes. 

 He thought it was but right that he should call attention to this 

 difference without wishing in any way to detract from the value 

 of the paper. Mr. Barnaby, the Chief Constructor of the British 

 Xavy, was, he believed, in the room, and as he was a very large 

 user of steel and iron, they would be glad to hear his views. 



In closing the Discussion, 



The PRESIDENT said he only wished to refer to two points in 

 the discussion. One was an observation by Mr. Kitson, to the 

 effect that steel did not stand heating and cooling as well as iron. 

 Now, he had received from Messrs. Easton and Anderson, only the 

 previous day, a statement of some very interesting experiments 

 which they had made with steel boilers. The cylindrical bodies 

 were heated to redness, then plunged into cold water, and again 

 reheated and flanged. In other experiments they were flanged 



