134 THE SCIENTIFIC PAPERS OF 



them to consist of about -ifchs of carbonic oxide and -J-th of car- 

 bonic acid, and if this proportion was invariable, it would be 

 possible to say with great precision what would be the amount of 

 heat developed by a given amount of blast of a given temperature. 

 There were several duties to be performed by the heat thus 

 developed. The iron oxide had to be deoxidized or reduced, 

 and the iron had to be melted. The " gang " and flux had 

 to be combined and melted; and the products of combustion 

 themselves escaped at the top at a certain temperature, which im- 

 plied a loss of heat. But, without going into a priori calculations 

 of these separate duties, he found that the necessary consumption 

 of coke to smelt a ton of iron from Cleveland iron-stone, contain- 

 ing 40 per cent, of iron, could not be less than 19'6 cwt. This limit of 

 economy could not be surpassed, however much the capacity of the 

 furnace might be increased ; it was the limitation which could be 

 approached but never exceeded, except by raising the temperature 

 of the blast to a higher point. In doing that there was heat im- 

 parted from without the furnace, which necessarily saved a similar 

 amount of heat that had to be developed inside the furnace, by com- 

 bustion of coke by means of the blast. In continuing this argument 

 it might be thought, at first sight, that the burning of 1 pound of 

 fuel in the stoves would save 1 pound of coke in the blast furnace ; 

 and this would really be the case, if the products of combustion 

 of the blast furnace were carbonic acid, as in the stove ; but in- 

 asmuch as the escaping gases were a mixture of carbonic acid with 

 carbonic oxide, in the proportion of 1 to 4, the number of units of 

 heat produced within the furnace per Ib. of fuel would be reduced in 

 the proportion of 14,000 : $ 4,000 + 14,000 or of 14,000 : 6,000 ; 

 that was to say, the number of units of heat produced by each 

 pound of carbon consumed in the blast furnace did not exceed 

 6,000 ; whereas each pound of carbon burned in the stove would 

 produce 14,000 units. It was evidently, therefore, important to 

 raise as much heat in the stove as possible, in order to save more 

 than double the amount in the blast furnace ; and when it was 

 borne in mind, that the fuel in the stoves was obtained for 

 nothing by burning the waste gases from the top of the blast 

 furnace, it was obvious that there was the strongest argument for 

 getting as much heat as possible in that way. The argument in- 

 sisted upon by some ironmasters, that it would be no use to go 



