with oxides is red-short. In practice, blooms made
by this process have been so red-short that they could not be hammered
at all.

It would be impracticable in this process to employ ore and carbon in
as fine particles as Wilson does, as a very large portion of the
charge would be carried off by the draught, and a sticking of the
material to the sides of the rotating furnace could scarcely be
avoided. I do not imagine that a division of the material into
anything like the supposed size of molecules is necessary; we know
that the graphitic carbon in the pig-iron employed in puddling is not
so finely divided, but it is much smaller particles than bean or pea
size, and by approximating the size of the graphite particles in pig
iron, Wilson has succeeded in obtaining good results.

If we examine the utilization of the heat developed by the combustion
of a given quantity of coal in this process, and compare it with the
result of the combustion of an equivalent amount of fuel in a blast
furnace, we shall soon see the theoretical economy of the process. The
coal is burned on the grate of the puddling-furnace, to carbonic acid,
and the flame is more fully utilized than in an ordinary
puddling-furnace, for besides the ordinary hearth there is the second
or rear hearth, where additional heat is taken up, and then the
products of combustion are further utilized in heating the retorts in
which the ore is partly reduced. After this the heat is still further
utilized by passing it under the boilers for the generation of steam,
and the heat lost in the gases, when they finally escape, is very
small. In a blast furnace the carbon is at first burned only to
carbonic oxide, and the products of combustion issue mainly in this
form from the top of the furnace. Then a portion of the heat resulting
from the subsequent burning of these gases is pretty well utilized in
making steam to supply the power required about the works, but the
rest of the gas can only be utilized for heating the blast, and here
there is an enormous waste, the amount of heat returned to the furnace
by the heated blast being very small in proportion to the amount
generated by the burning of that portion of carbonic oxide expended in
heating it, and the gases escape from both the hot-blast and the
boilers at a high temperature.

In the direct process under consideration the fuel burned is more
completely utilized than in the puddling process, to which the cast
iron fr