218 ANNUAL OF SCIENTIFIC DISCOVERY. 



Third Sample, taken out at Ih. 5m. 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. 

 "When cold, it 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 globules, 

 when broken, presented a bright metallic lustre, and were ver) 7 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 siev- 

 ing we could separate it from the iron, which was much less friable. The 

 iron thus cleansed from its scoria gave us the following results : 



First analysis. Second analysis. Mean. 



Carbon, 2-466 2-421 2444 



Silicium, 0-188 0-200 0-194 



Fourth Sample, taken out at Ih. 20m. p. M. 



As soon as the last sample had been taked out, the damper of the furnace 

 was slightly raised, so as to admit a gentle current of air, which did aAvay 

 with the smoke which had been issuing from the puddler's door, and a clear 

 and bright flame was the result. This was done, no doubt, to facilitate the 

 oxidation of the carbon of the iron, and to increase this action the puddler 

 quickly agitated the mass. Under these two actions, the mass swelled up 

 rapidly, and increased to at least four or five times its original bulk ; and at 

 Ih. 20m., the mass being in full boil, this fourth sample was taken out. 

 Whilst cooling, it presented the interesting fact, that in various parts of it 

 small blue flames of oxide of carbon were perceived, no doubt arising from 

 the combustion of carbon by the oxygen of the atmosphere. It is curious 

 that this phenomenon was not observed in the previous samples. It is due 

 probably to the following causes: first, that the cast iron, having been 

 brought by the boil to a state of minute division, offers a large surface to the 

 action of the oxygen of the air, and thus the combination of the oxygen 

 with the carbon of the iron is facilitated : and second, that at this period the 

 carbon seems to possess little or no affinity for the iron; for one of us has 

 often observed that when pig iron, rich in graphite, is puddled, the carbon is 

 liberated from the iron; for if a cold iron rod is plunged into the mass of 

 melted iron in the puddling furnace, it is covered with iron and abundant 

 shining scales of graphite carbon. 



The appearance of this No. 4 sample was most interesting; and the best 

 idea that we can give of it is, that it is so light, and formed of such minute 

 granules, as to be exactly like an ant's nest. The particles have no adherence 

 to each other, for by merely handling of the mass it falls into pieces. This 

 is due to each particle of iron being intimately mixed with scoria. The 

 granules of iron have a black external appearance, are very brittle under the 

 hammer, and when broken they present a bright, silvery, metallic fracture. 

 The scoria was separated by the method above described for No. 3, and the 

 quantities of carbon and silicium which the iron contained were as follows : 



