CHEMICAL SCIENCE. 217 



had been cleaned out with malleable iron scraps. After thirty minutes, the 

 pisrs betran to soften and to be easily crumbled, and ten minutes more had 

 hardly elapsed when they entered into a state of fusion. The first sample 

 was taken out of the furnace at 12h. 40m. P.M., from the centre of the 

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



On breaking the sample as taken out of the furnace, it had no longer the 

 appearance of gray No. 3 pig iron, but a white, silvery, metallic fracture, 

 similar to that of refined metal. The rapid cooling of the sample was no 

 doubt the cause of the change noticed, for it contained quite as much carbon 

 as the pig iron used; and further, the carbon was in a very similar condition, 

 as in both cases a large quantity of black flakes of carbon floated in the acid 

 liquors in which the iron was dissolved. The following is the amount of 

 carbon and silicium which the above sample contained per cent. : 



First analysis. Second analysis. Mean. 



Carbon,. 2-673 2780 2-726 



Silicium, 0'893 0938 0-915 



These results are highly interesting, as they show that the iron had under- 

 gone, during the forty minutes which it had been in the furnace, two opposite 

 chemical changes; for whilst the proportion of carbon had increased, the 

 quantity of silicium had rapidly decreased. This curious fact is still further 

 brought out by the sample which we took out of the furnace at 1 p. M., or 

 twenty minutes later than the last sample analyzed, as is shown in this table : 



Carbon. Silicium. 



Pig iron used, 2-275 2-720 



First sample taken out at 12h. 40m., 2-726 915 



Second sample taken out at Ih. Om., 2-905 0-197 



Therefore the carbon had increased 0'625, or 21 "5 per cent, of its own 

 weight, and the silicium had decreased in the enormous proportion of above 

 90 per cent. It is probable that these opposite chemical actions are due, in 

 the case of the carbon, to the excess of this element in a great state of di- 

 vision, or in a nascent state in the furnace, and that under the influence of 

 the high temperature it combines with the iron, for which it has a great 

 affinity, whilst the silicium and a small portion of iron are oxidized and com- 

 bined together, to form protosilicate of iron, of which the scoria or slag 

 produced during this first stage of puddling consists, and which plays such 

 an important part in the remaining phenomena of the puddling process. 



Second Sample, taken out of the furnace at Ih. Om. p. M. 

 This sample contained the following quantities of carbon and silicium: 



First analysis. Second analysis. Mean. 



Carbon 2-910 2-900 2.905 



Silicium, 0226 0-168 0-197 



It had the same white, silvery appearance as No. 1 ; but had this differ- 

 ence, that it was slightly malleable under the hammer, instead of being 

 brittle like No. 1. The scoria also was on the upper surface of the mass 

 when cold, and not mixed with the metallic iron, as in succeeding examples. 



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