282 THE SCIENTIFIC PAPERS OF 



chemical reason and the same practical result applied to silicon, 

 although he would quite admit certain drawbacks, which Mr. Bell 

 had alluded to, to the presence of much silicon in the pig metal. 

 The silicon in the pig metal had to be combined with oxide of 

 iron to form a tribasic slag, and this oxide of iron had to be 

 supplied by the fettling. Therefore, if they puddled an iron con- 

 taining much silicon they would require an extra amount of 

 fettling to dissolve the silicon afterwards in the slag, and in the 

 absence of this extra supply of fettling the operation would not 

 progress favourably ; but the chemical reasoning still held good. 

 They could obtain from pig metal rich in silicon a larger yield 

 than from the same pig metal containing no silicon, the simple 

 reason being that the atomic weight of silicon was considerably 

 less than the atomic weight of iron. In his paper read before the 

 British Association he had shown that in puddling ordinary forge 

 pig iron the theoretical increase of weight was about 8 per cent., 

 and that he had already obtained weight for weight in practical 

 puddling taking the average result of six months' working 

 without using more fettling ore than was necessary under all 

 circumstances to accomplish the operation. 



ME. SIEMENS said he had certainly misunderstood the remarks 

 made by Mr. Jones on the previous day, perhaps it was because 

 he had not explained them fully. He had understood that 

 Mr. Jones thought it possible that the Siemens-Martin process of 

 making steel could be carried out in the Danks furnace. If the 

 question was one of puddling Cleveland pig so as to make it 

 suitable for this process, he would not say a word against it, except 

 that he must see the analysis of the puddled material before he 

 made up his mind as to its merits. If that analysis were shown to 

 him he would be able to say at once whether the metal was suit- 

 able or not for the Siemens-Martin process, because he knew 

 exactly how much phosphorus and how much sulphur he could do 

 with ; and if in the first instance Mr. Samuelson had put clearly 

 to him the question whether he would be able to make steel from 

 Cleveland pig, he (the speaker) would most decidedly have told 

 him that he did not believe he could. He thought it could not 

 be done unless they could show him that they could remove 

 phosphorus to a much greater extent than the ordinary puddling 



