CHEMICAL EFFECTS OF PUDDLING. 129 



Appearance or the Sample. — On breaking the sample 

 as taken out of the furnace, it had no longer the appearance 

 of grey No. 3 pig iron, but had 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 fol- 

 lowing is the amount of carbon and silicium which the above 

 sample contained per cent. 



First Analysis. Second Analysis. Mean. 



Carbon 2.673 2.780 2.726 



Silicium 0.808 0.938 0.915 



These results are highly interesting, as they show that the 

 iron had undergone, during the 40 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 20 minutes 

 later than the last sample analysed, as is shown in this 

 table. 



Carbon. Silicium. 



Pig Ironuaad ... 2.275 2.720 



First Sample taken out at 12.40 2.726 0.915 



Second Sample taken out at 1 p.m 2.905 0.197 



Therefore the carbon had increased 0.630 or 21.5 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 state of minute division, or 

 in a nascent state, in the furnace, and that under the influ- 

 ence of the high temperature it combines with the iron, for 

 s 



