In 1831, Neilson's hot blast specification had been published for two
and a half years only. The Butterly Company had tried the hot blast
for the first time in the November preceding the meeting of the
British Association. The heating of the blast was coming very slowly
into use, and the temperature attained when it was employed was only
some 600 degrees. The ordinary blast furnace of those days was 35 to
40 feet high, and about 12 feet diameter at the boshes, and turned out
about 60 tons a week. It used about 21/2 tons of coal per ton of iron,
and no attempt was made to utilize the waste gases, whether escaping
in the form of gas or in the form of flame, the country being
illuminated for miles around at night by these fires. The furnaces
were also open at the hearth, and continuous fire poured out along
with the slag.
In 1881, blast furnaces are from 90 ft. to 100 ft. high, and 25 ft. in
diameter at the boshes; they turn out from 500 to 800 tons a week. The
tops and also the hearths are closed, and the blast--thanks to the use
of Mr. E.A. Cowper's stoves--is at 1,200 degrees. The manufacture of
iron has also now enlisted in its service the chemist as well as the
engineer, and among those who have done much for the improvement of
the blast furnaces, to no one is greater praise due than to Mr.
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