792 
a hundred and twenty-five thousand to a hun- 
dred and forty thousand tons. This wonder- 
ful gain has been entirely due to American 
genius, and principally to the splendid engineer- 
ing of the late A. L. Holley, who told his 
friend Thomas, the inventor of the ‘ basic 
process’ (who, when visiting the steel-works at 
Troy, looked for an ingot-mould on which to 
seat himself after a fatiguing tour of the estab- 
lishment), that, if he wished to find an ingot- 
mould cool enough to sit upon, he must go 
back to England for it. 
A sketch of Sir William Siemens follows 
that of Sir Henry Bessemer, and a very good 
account is given of the so-called Siemens pro- 
cess of making steel. For a short outline of 
the life of this wonderfully versatile inventor 
and engineer, the reader may turn to the col- 
umns of Science for Jan. 11; but he will find 
a more detailed story of his life in the Crea- 
tors of the age of steel. 
The Siemens process of steel- making differs 
from the Bessemer process, of which it is in 
some sense a rival, but with which it is more 
strictly a coadjutor, in being a slow and gradual 
operation, conducted upon the hearth of a rever- 
beratory furnace, — an ‘ open-hearth ’ furnace, 
as it is often called,—#éinstead of being a 
process of rapid reduction in a closed vessel, in- 
accessible to the operator at any time during the 
period of change. ‘This slowness of transition 
from the condition of cast to that of wrought 
iron, and the perfect accessibility permitted by 
the use of the open-hearth furnace, afford the 
workman an opportunity to watch the process 
of evolution of carbon, and to check it, if he 
desires, at any stage; to increase or diminish 
the proportions of any element, as he may find 
it necessary ; and thus to obtain with certainty 
precisely the quality that he seeks. In the 
Bessemer process, the right proportions must 
be hit upon at the right instant, or the error 
permanently injures the product, and cannot 
be rectified. 
metal is not right when ready to tap off, the 
operator can readjust the proportions of carbon 
or of manganese until he finds, by test of 
samples taken from the furnace, that it is pre- 
cisely as he wishes it; and he can then cast it 
into ingots with a positive certainty that he will 
obtain a marketable product. In this process, 
too, the refuse scrap, the rail-ends, and other 
waste from the Bessemer converter, can be 
worked up; and by it a great market for scrap 
wrought-iron is made. 
A long and sometimes sharp controversy has 
arisen between the friends of the two great 
inventors, and especially between the friends 
SCIENCE. 
In the Siemens process, if the 
ie 
of Siemens and of Martin, who introduced 
this process in France, as to the priority and 
the relative merits of the inventions. The 
true facts of this case are probably correctly 
given by a committee of the Styrian metal- 
lurgical association, who voted that the prin- 
ciple of making cast-steel on the hearth of a 
reverberatory furnace was known at the begin- 
ning of the century, and that it was success- 
fully practised in France in 1860; that Sir 
William Siemens invented the process of mak- 
ing steel in the Siemens regenerative furnace ; 
that Martin discovered the proper mixtures. 
for the commercial grades of steel; that the 
processes devised by the latter have been now 
superseded, and are of no present use. There 
is and can be no rivalry between the Bessemer 
and the Siemens processes, or their inventors. 
They occupy entirely different fields of pro- 
duction; and each is peculiarly adapted to 
making a special kind of steel, and to working 
up materials such as the other is least fitted 
to handle. Each has its place in our indus- 
trial system, and each is of direct and sub- 
stantial value to the other. The Bessemer 
process will probably make the bulk of our 
steel rails, and the Siemens process will prob- 
ably supply us with the best of boiler-plate, 
for an indefinite period of time. We shall 
always find a field open to both, and shall al- 
ways see each taking its own place, and filling 
it in a manner that the other cannot imitate. 
The original Siemens process was one in 
which the carbon was removed from cast-iron, 
partly by dilution with wrought-iron scrap- 
metal, and partly by oxidation in the flame of 
the reverberatory furnace of Siemens, and 
also, perhaps, to some extent by ‘ dissociation.’ 
This method of making ‘ mild steel’ involved 
the use of a large quantity of scrap, and al- 
though at first a very economical process, 
and continuing to be economical so long as 
scrap-iron flooded the market, as it did at the 
first, became uneconomical, comparatively, 
as the price of wrought-iron scrap advanced. 
Siemens then introduced his so-called ‘ ore 
process,’ in which the reduction of the carbon 
was effected by the use of the ores of iron. 
The process as now usually conducted, under 
the direction of the agents of the inventor, is" 
a mixed ore and scrap process. 
The peculiarity of the product of the Siemens 
process is the wonderful uniformity, toughness, 
and purity of the metal. The most stringent. 
demands of the engineer are readily met by 
the open-hearth steel-maker; and the most. 
delicate shades of quality are obtained with 
an ease and accuracy that are approached by 
[Vou. IIL, No. 73.5 7 
