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[January, 
EXPLANATORY REPORTS ON NEW 
SCIENTIFIC PROCESSES AND INVENTIONS. 
[These Reports will not partake of the nature of an Advertisement, but will 
be impartial descriptions, written and signed by well-known Specialists. — 
Ed. J. S.] 
The Thomas and Gilchrist Process for Eliminating 
Phosphorus in the Manufacture of Steel. 
Until recently the puddling of pig-iron was regarded simply as 
a process of oxidation, and it was not until the practical working 
of the Bessemer converter revealed the facft that neither sulphur 
nor phosphorus are effectively removed in it, that the mere 
oxidation theory was abandoned. 
Now we know that puddling does something more, that oxida- 
tion alone, though fully effectual in removing silicon and carbon, 
fails in the elimination of sulphur and phosphorus. It is on this 
account that special “ Bessemer pigs ” have to be made from 
haematite or other rich ores nearly free from these impurities. 
Such are scarce in this country (they amount to only about 12 
or 13 per cent of our native ores), while clay ironstones con- 
taining much phosphorus are very abundant. Now that mild 
Bessemer steel is so largely superseding wrought-iron, and the 
iron-masters of the North have eredted huge blast-furnaces in 
the midst of the impure phosphoric Cleveland ores, very large 
interests are involved in any effort to render the Cleveland pig 
available for Bessemer or Siemens-Martin purposes. 
The theory of the failure of oxygen in removing phosphorus 
is not yet fully cleared up, though it has been much discussed. 
Knowing the extreme readiness with which our old chemical 
plaything, the stick of phosphorus, unites with oxygen, it was 
theoretically regarded as the first to be driven off in the course 
of the vivid combustion of a Bessemer “ blow,” but such is not 
the case ; the silicon burns freely, the carbon follows, and then 
the iron itself ; while the phosphorus and sulphur remain, as 
though they were incombustible substances. The probable cause 
of this anomaly is, that at very high temperatures iron is able 
to reduce both sulphurous and phosphoric acids, just as carbon 
at high temperatures reduces the oxides of metals which at lower 
temperatures have much stronger affinities for oxygen than 
carbon has. Thus the phosphoric acid may be formed and im- 
mediately reduced, and its phosphorus re-combined with the iron 
as before. But if we can put something else in the way that shall 
