264 
furnace tends to counteract red shortness. With respect 
to others of the defects to which I have alluded, we can 
explain some by the process of manufacture, some we can 
only guess at, and of the causes of some we are quite 
ignorant. Two conclusions alone appear to be undisputed, 
namely, that extremely small quantities of extraneous sub- 
stances in chemical combination with iron, produce most 
striking alterations in its quality, although such quantities 
of extraneous substances may be so minute as almost to 
elude the analysis of the scientific chemist ; also that many 
of the qualities of iron depend on the particular arrange- 
ment of its molecular particles, which may be influenced and 
altered by merely mechanical operations. 
Mr. Blackwell says that the gross annual production of 
iron in Great Britain at the present time is upwards of 
2,250,000 tons; of this quantity South Wales furnishes 
700,000 tons, South Staffordshire and Worcestershire 
600,000 tons, and Scotland 600,000 tons. The remaining 
350,000 tons are from North Staffordshire, Shropshire, 
Derbyshire, Yorkshire, and various smaller districts. 
The first process in making iron is its reduction from the 
ore, which is roasted or calcined in a heap with coal to expel 
water, sulphur, arsenic, and such other extraneous matters 
as can be easily volatilized, especially carbonic acid. The 
ore is mixed with certain proportions of fuel, (charcoal, 
coke or coal,) and smelted in a large and lofty furnace, 
termed a blast furnace, so called because the combustion 
is supported by a powerful blast of air driven into the furnace 
by a steam engine. Charcoal is now almost entirely discarded 
in England as a fuel, on account of its cost, though it unques- 
tionably produced better iron. I am disposed to believe that 
the principal advantage of charcoal arises from its being the 
purest fuel, because the next best iron is that made with 
anthracite coal, the next best with coke, and lastly with raw 
