1 28 MR. F. C. CALVERT AND MR. R. JOHNSON ON THE 



current of air is not managed with great care the iron itself 

 is oxidized, or, as it is technically termed, "burnt;" and thus 

 not only does great loss ensue in the quantity of malleable 

 iron produced, but also the iron containing a certain quantity 

 of oxide of iron is brittle and of bad quality. 



We shall now examine the various chemical changes which 

 pig iron undergoes during its conversion into wrought iron. 



The iron we took for our experiments was a good cold 

 blast Staffordshire iron, the pig was rather grey, being of 

 the quality used for making iron wire, or a grey No. 3. Its 

 composition was as follows : — 



First Analysis. Second Analysis. Mean. 



Carbon 2.320 2.230 2 275 



Silicium 2.770 2.670 2.720 



Phosphorus 0.580 0710 0.645 



Sulphur 0.318 0.288 0.301 



Manganese and Aluminum... Traces 



Iron 94.059 94.059 94.050 



100.047 99.957 100.000 



First Sample, taken out of the furnace at 12 40 p.m. 



Two hundred and twenty-four pounds of the above pig 

 iron were introduced at twelve o'clock, on the 14th of April, 

 1856, into a puddling furnace, which had been cleaned out 

 with wrought iron scraps. After 30 minutes the pigs began 

 to soften and to be easily crumbled, and 10 minutes more had. 

 hardly elapsed when they entered into fusion. A sample was 

 immediately taken out from the centre of the melted mass, 

 with a large iron ladle, and poured on a stone flag to cool. 

 The flue of the furnace, which had hitherto been kept open, 

 was now, nearly closed by a damper at the top of the chimney, 

 so that the products of combustion came out by the door of 

 the furnace and other openings, whilst little or none escaped 

 by the chimney. 



