on of the well known flameless
combustion, how to light a coke furnace without either paper or wood, and
without disturbing the fuel, by the use of a blowpipe which for the first
minute is allowed to work in the ordinary way with a flame to ignite the
coke. I then pinch the gas tube to extinguish the flame, allow the gas to
pass as before, and so blow a mixture of unburnt air and gas into the
fuel. The enormous heat generated by the combustion of the mixture in
contact with the solid fuel will be appreciable to you all, and if this
blast of mixed air and gas is continued, there is hardly any limit to the
temperatures which can be obtained in a furnace. I shall be able to show
you the difference in temperature obtained in a furnace by an ordinary air
blast, by a blowpipe flame directed into the furnace, and by the same
mixture of gas and air which I use in the blowpipe being blown in and
burnt in contact with the ignited coke. In each case the air blast, both
in quantity and pressure, is absolutely the same; but the roar and the
intense, blinding glare produced by blowing the unburnt mixture into the
furnace is unmistakable. The heat obtained in the coke furnace I am using,
in less than ten minutes, is greater than any known crucible would stand.
I am informed that this system of air and gas or air and petroleum vapor
blast, first discovered and published by myself in a work on metallurgy
issued in 1881, is now becoming largely used for commercial purposes on
the Continent, not only on account of the enormous increase in the heat,
and the consequent work got out of any specified furnace, but also because
the coke or solid fuel used stands much longer, and the dropping, which is
so great a nuisance in crucible furnaces, is almost entirely prevented; in
fact, once the furnace is started, no solid fuel is necessary, and the
coke as it burns away can be replaced with lumps of broken ganister or any
infusible material. Few, if any, samples of firebrick will stand the heat
of this blast, if the system is fully utilized. You will find it a matter
of little difficulty, with this system of using gas, to melt a crucible of
cast iron in an ordinary bed-room fire grate if the front bars are covered
with sheet iron, with a hole (say) three inches in diameter, to admit the
combined gas and air blast. The only care needed is to see that you do not
melt down the firebars during the process. I will also show you how, on an
ordinary table, w