many cases risen to 18 per cent.; so that an unpleasant ratio
exists between the wages of the workmen and the amount of sulphur in
the coal raised. It is therefore not remarkable that, even when ores
fairly free from sulphur are treated, it easily happens that a
sulphureted pig iron is obtained.

In order to effect satisfactory desulphurization, attention has been
bestowed on the fact that iron sulphide is converted by manganese into
manganese sulphide and iron. If sulphureted pig iron, poor in
manganese, is added in a fluid condition to manganiferous molten pig
iron, poor in sulphur, the metal is desulphurized, and a manganese
sulphide slag is formed. It may be urged that it does not seem
necessary to effect the desulphurization by means of the reaction of
the manganese and iron sulphide outside of the blast furnace, as it is
possible, by suitably directing the blast furnace, by the employment
of manganiferous ores or highly basic slag, so to desulphurize the
iron in the blast furnace itself that it would be unnecessary further
to lower the percentage of sulphur. Every blast furnace manager,
however, will have observed that, even with every precaution in the
blast furnace practice, pig iron will often be obtained with so high a
percentage of sulphur as to render it useless for the Bessemer acid or
basic processes. If the desulphurization in the blast furnace is
carried sufficiently far, it is always necessary to work the furnace
hot, and thus to obtain hotter iron than is desirable for further
treatment in the converter. On the other hand, the method of further
desulphurization outside the blast furnace, described in this paper,
presents the double advantage that part of the blast furnace can be
kept cooler, and thus lime and coke be saved, and that there is a
certainty that no red-short charges are obtained in the treatment in
the converter, while the pig iron passes to the converter at a
suitable temperature.

[Illustration: FIGS. 1 through 5]

A further advantage presented by the direct process described in this
paper is that the Bessemer works is independent of the time at which
the individual blast furnaces are tapped, as the pig iron required for
the Bessemer process can be taken at any moment from the
desulphurizing plant. In Hoerde, where the mixing and desulphurizing
process has for a considerable time been regularly in use, it has been
found that all the chief difficulties formerly encountered in the
meth