260 THE SCIENTIFIC PAPERS OF 



was given to the cooling material or regenerator, equilibrium 

 would never be established, and it would not be possible to cool 

 down the escaping current to the temperature of the entering 

 draught ; or, applying this argument to the case of the blast 

 furnace, it would not be possible to cool down the escaping gas to 

 the temperature at which the fresh materials were charged into 

 the furnace, owing to the inferior total capacity for heat of the 

 latter. 



With regard to the amount of chemical work which was required 

 to be performed in a blast furnace for smelting a ton of iron, he 

 had made a calculation, the results of which it might be interest- 

 ing to compare with those that had been arrived at by adapting 

 to the Cleveland furnaces the investigations of the foreign writers 

 referred to, whose researches upon the subject he had not previ- 

 ously been acquainted with. In the case of Cleveland ironstone 

 containing 40 per cent, of metallic iron in the calcined ore, the 

 iron being in the state of peroxide had 17 per cent, of oxygen 

 combined with it, and the remaining 43 per cent, of the ore would 

 be silica. To fuse this 43 per cent, of silica, which was equal to 

 21| cwts. per ton of iron made, 7 cwts. of calcined limestone 

 would theoretically be required, but in reality he believed 8 or 9 

 cwts. of limestone was the quantity generally added in the Cleve- 

 land district ; these would take up about 2| per cent, of iron, 

 giving a total of about 31 cwts. of cinder per ton of iron made. 

 The 17 per cent, of oxygen combined with the 40 per cent, of 

 iron in the ore was equivalent to 8'50 cwts. of oxygen per ton of 

 iron, and this would require 5 '31 cwts. of carbon to produce the 

 mixture of f ths carbonic oxide and ^th carbonic acid which he 

 believed actually resulted from the chemical reactions in the 

 furnace ; for although it had been calculated in the paper that the 

 proportions in which these two gases passed off at the furnace top 

 were about frds carbonic oxide to |rd carbonic acid, he thought 

 the difference should be allowed for the amount of carbonic acid 

 evolved from the limestone, and that there would therefore be no 

 material error in assuming the result of the combustion to be -f-ths 

 carbonic oxide and ^-th carbonic acid. 



The heat necessary to be produced in the blast furnace was 

 therefore that required for performing the three distinct opera- 

 tions of melting the iron itself, melting the cinder accompanying 



