130 MR. F. C. CALVERT AND MR. R. JOHNSON ON THE 



which it has a great affinity ; whilst the silicium and a small 

 portion of iron are oxidized and combined 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 at 1 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 0.226 0.168 0.197 



It had the same white silvery appearance as No. 1, but with 

 this difference, that it was slightly malleable under the 

 hammer, instead of being brittle like No. 1. The scoria 

 also is on the upper surface of the mass when cold, and 

 not mixed with the metallic iron as in preceding samples. 



Third Sample, taken out of the furnace at 1 5 p.m. 



The mass in the furnace having become very fluid and 

 beginning to swell or enter into the state called " the boil," 

 a small quantity was ladled out. The appearance of the 

 sample when cold was quite different from that of the two 

 previous ones, being composed of small globules adhering 

 to each other and mixed with the scoria ; the mass therefore 

 was not compact like the former ones, but was light and 

 spongy, its external appearance was black, and the small glo- 

 bules, when broken, presented a bright metallic lustre, and 

 were very brittle under the hammer. 



We had, for some time, considerable difficulty in separating 

 the scoria from the globules of iron, but we found that by 

 pulverizing the whole for a long time, the scoria was reduced 

 to impalpable powder, and by sieving we could separate it 



