4 



inasmuch as for some time previous to 1825, a saving in the 

 coking operation had been made at every well-conducted iron 

 work, by which a ton of iron could be make with 5 tons of 

 splint coal in the furnace, when cold blast was used ; so that 

 in reality a saving only took place (by increasing the tem- 

 perature of the air, so far as to enable them to use coal 

 uncoked in the smelting furnace) of 2 tons 5 cwt., that is, 

 from 5 tons to 2 tons 15 cwt. 



The account, therefore, as regards economy, by the use of 

 hot air, will stand thus : — 



Tons. Cwts. d. £. d. 



Saving in coal used in the furnace 2 5 500113 

 In Coker's Wages 0 2 3 



£0 13 6 



Against this may be set down — 

 A greater quantity of ironstone 



used per ton of iron made 0 3 860 1 3 



Extra wear on ditto 0 3 6 



Coal to heat the air used 0 8 2 0 0 010 



£0 5 7 



Saving in materials by the use of hot air, per ton 



of iron 0 7 11 



To which saving may be added a further sum of 4s. 7d. per 

 ton, for the greater quantity of iron produced from each 

 furnace, when hot air and coals are used, making the total 

 saving of 12s. 6d. per ton of pig iron. 



But in 1835 the deterioration in the value of iron so made 

 was about 17s. 6d. per ton, as I stated at Dublin, and at the 

 present time, (March, 1842) I have no recantation to read so 

 far as the above observations go. 



And in comparing this with the make by hot air, in December, 1836, (one of the 

 best months in the year for iron making), an addition of 8 cwt. of coal being 

 made for heating the air, the difference is truly so small as to be altogether 

 unworthy of consideration, on taking into account the deteriorated value of the 

 produce. 



