In the early part of the year 1829, the use of hot air in the smelting furnace, for the manufacture of cast iron, was introduced at the Clyde Iron Works, near Glasgow; and at the fourth meeting of the British Association, held at Edinburgh in 1834, Dr. Clark gave an account of its success as follows:—
“That in their previous operations with cold air, 8 tons 1 cwt. 1 qr. of splint coal (made into coke, at a loss in weight of fifty-five per cent.), was required to make 1 ton of iron.
With the use of air heated to about 300° Fahrenheit, 5 tons 3 cwt. 1 quarter of coal (in coke) produced a ton of iron, in addition to which, 8 cwt. of coals were used for heating the air.
In 1833, the temperature of the air used being 600° Fahrenheit, it was found that raw coal (not coked) might be used, which circumstance further reduced the quantity of coal required in the furnace to 2 tons 5 cwt. 1 qr. per ton of iron made.”
Not having been present at Edinburgh, on the Association’s meeting the following year in Dublin, I stated that the case had not been correctly represented to Dr. Clark, * 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 ...
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