the same length of
time.

Observations on the more recent Researches concerning the operations
of the Blast Furnace in the Manufacture of Iron.

BY DR. J. L. SMITH.

The great difference existing between metallurgical operations of the
present day, and those of a former period, is owing chiefly to the
ameliorations produced by the application of the science of chemistry
to the _modus operandi_ of the various changes taking place during the
operations, from their commencement to their termination.

Copper and some other metals are now made to assume forms in the
chemist's laboratory, that formerly required great artistical skill
for their production--the chemist simply making use of such agents and
forces as are at his command, and over which he has, by close
analytical study, acquired perfect control. Our object, at present, is
only to advert to the chemical investigations more recently made on
the manufacture of iron, treating of those changes that occur in the
ore, coal and flux, that are thrown in at the mouth of the furnace,
and in the air thrown in from below. For most that will be said on
this subject, we are principally indebted to the recent interesting
researches of M. Ebelman.

The importance of a knowledge of the facts to be brought forward, in
this article, will be apparent to every one in any way acquainted with
the manufacture of iron. It will be seen that the time is not far
distant when the economy in the article of fuel will amount in value
to the present profit of many of the works. The consequences must be,
that many of those works that are abandoned will be resumed, and
others erected in localities formerly thought unfit.

It is well known that the blast furnace is the first into which the
ore is introduced, for the purpose of converting it into malleable
iron, and much, therefore, depends upon the state in which the pig
metal passes from this furnace, whether subsequent operations will
furnish an iron of the first quality or not.

In putting the blast furnace into operation, the first step is to heat
it for some time with coal only. After the furnace has arrived at a
proper temperature, ore, fuel and flux, are thrown in alternately, in
small quantities, so as to have the three ingredients properly mixed
in their descent. In from 25 to 48 hours from the time when the ore is
first thrown in, the entire capacity of the furnace, from the tuyer to
the mouth, is occupied with the ore, fuel a