

SfK WILLIAM SIEMENS, F.R.^ 263. 



necessary for the smelting of ono ton of iron. The complets con- 



Kiiiii|itiini was therefore as follows : 



Cwte. 



Melting tin; iron 1'Ou 



Melting the cinder 4'18 



Meat rendered latent by reduction of the ore 3'19 

 Carbon for combining with oxygen in ore 

 and for carbonising pig metal . . 7'43 



16-35 



Ashes and water in the coke, 10 per cent. . . 1'63 

 Calcining the limestone, &c., 10 per cent. . . l'G3 



Total quantity of coke required . . 19-61 cwts. 



In this calculation he had left out of consideration on the one 

 hand the heat that was carried off from the furnace by the escaping 

 gas, and on the other hand the heat brought into the furnace by 

 the hot blast entering at 1000 Fahr. ; but on comparing these 

 two quantities of heat it would be found that they balanced each 

 other very nearly indeed. For the 8"9 2 cwts. of carbon made up 

 by the first three items in the foregoing estimate would require, 

 in order to produce blast-furnace gas consisting of fths carbonic 

 oxide and |th carbonic acid, 14' 2 7 cwts. of oxygen, which would 

 be contained in 62*04 cwts. of atmospheric air entering as hot 

 blast ; while on the other hand the gas escaping at the furnace 

 top would contain the whole of these 8'92 cwts. of carbon and 

 62'04 cwts. of air, together with the 8'50 cwts. of oxygen existing 

 in the ore and the 5'31 cwts. of carbon supplied into the furnace 

 to combine with it, making altogether 84'77 cwts. of gas, to which 

 had to be added about 10 per cent, or 8*47 cwts. of carbonic acid 

 and vapour of water generated from the limestone and other 

 materials, thus making up a total weight of 93'24 cwts. of gas 

 escaping from the furnace top, in the form of carbonic oxide, 

 carbonic acid, and nitrogen mixed together. Assuming the tem- 

 perature of this escaping gas to be 600 Fahr. and the specific 

 heat of the mixture to be the same as that of air or 0*267, the 

 total quantity of heat thus carried off from the furnace would be 

 93-24 x 112 x 600 x 0'267 = 1,672,949 units of heat per ton of iron 

 made ; and at the same time the heat brought into the furnace 



