1868. | Mechanical Science. 543 
sumption of coal, which, on good authority, threatens at no very 
distant period to outstrip our resources ; it was not surprising that 
the papers on this subject read before the mechanical section were 
looked forward to and listened to with the greatest possible interest. 
The paper, by Mr. C. W. Siemens, “On Puddling Iron,” was an 
attempt to trace the course of the chemical action which takes place 
during the puddling process; and the deduction drawn was, that 
the present method, which has now been maintained for many years 
without change or improvement, involves great loss of metal, waste 
of fuel and human labour, and an imperfect separation of the two 
noxious ingredients, sulphur and phosphorus. Experiments on a 
large scale, and a series of analyses of the iron in different stages of 
the process of puddling, appear to show that the molten metal is 
mixed intimately, in the first place, with a molten portion of the 
oxide or cinder (technically called the fettling) which forms the 
lining to the iron tray of the puddling chamber ; that the silicon is 
first separated from the iron, that the carbon only leaves the iron 
during the “boil,” and that the sulphur and phosphorus separate 
last of all while the iron is “coming to nature.” The object of Mr. 
Siemens was to show that much of the waste which takes place 
during this complicated action could be avoided by the use of a 
puddling hearth, heated by means of one of his regenerative furnaces, 
to the advantages of which he drew particular attention. These 
are, that the heat can be raised to an almost unlimited degree, that 
the flame can be made at will—oxidizing, neutral, or reducing— 
without interfering with the temperature, that draughts of air and 
cutting flames are avoided, and that the gas-fuel is free from pyrites 
and other impurities which are carried into the puddling-chamber 
from an ordinary grate. A furnace erected, on this principle, which 
has been in operation at the Bolton Steel and Ironworks for eighteen 
months, has given most excellent results; and the process is about 
being adopted by Messrs. Kitson, of Leeds, and others in this 
country. 
The production of steel by means of the mutual reaction of pig- 
iron, and wrought or other decarbonized iron, has been often at- 
tempted, but in consequence of the insufficient means of ensuring a 
very high temperature, without any practical success. Lately, how- 
ever, Messrs. Martin, of Paris, have succeeded by means of the 
Siemens’ regenerative furnace in obviating this defect, and it was to 
their process under the name of the Siemens-Martin process, that 
Mr. Ferdinand Kohn drew attention in his paper ‘“ On the Recent 
Progress of Steel Manufacture.” 
To the Messrs. B. Samuelson and Co., of the Newport Works, 
Middlesborough-on-Tees, is due the credit of being the first in 
the United Kingdom to manufacture steel for commercial purposes 
by this method, and, as yet, these are the only works established 
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