IRON AND STEEL. 
77 
penknives ; a yet deeper orange is required for table cutlery, 
and joiners’ edge-tools ; and a blue for watch-springs. These 
colours have been referred to oxidation ; but it is by no means 
satisfactorily shown that they are not due to a molecular 
arrangement, quite independent of any chemical change. 
Our process of preparing this useful metal is, to subject 
selected iron — usually Russian or Swedish — in contact with 
small pieces of wood-charcoal, in closed vessels, to a very high 
temperature, for some time, with a total exclusion of air. 
Different kinds of iron produce steels of different characters ; 
therefore the persons who possess this knowledge are enabled 
to prepare steel fitted for any required purpose. The Bessemer 
process has been employed with considerable success in the manu- 
facture of steel. One advantage is, that the decarbonization of the 
iron can be regulated with great accuracy. A given amount of 
ah’ passed through the incandescent iron, produces a known 
result, and this is registered by a dial. This process has advanced 
but slowly in England ; in Sweden, it has been extensively em- 
ployed. Large steel circular-saw-plates have been made by 
Mr. Groranson, the ingot being cast direct from the fluid metal, 
within fifteen minutes of its leaving the furnace. At Bordeaux 
furnaces are at work especially on this principle; and at Liege, 
from the native coke-iron, beautiful steel is made by the appli- 
cation of the discovery of Mr. Bessemer. At Sheffield, however, 
not only at the inventor’s works, but in some other large es- 
tablishments, the process of blowing' air through the molten 
iron to produce malleable iron and steel is now in use. 
All that has been attempted in this sketch is to give a 
sufficiently intelligible description of the processes by which 
our iron ores are converted into those metals which are so 
important to our manufacture and commerce, our main purpose 
being to indicate the large field of inquiry which is yet open to 
any zealous investigator. The iron ores of the United Kingdom 
have been analyzed with the most scrupulous care. These 
analyses, published in the “Memoirs of the Geological Survey,” 
may be regarded as the first step in the larger inquiry. Within 
the last year, considerable attention has been directed to the 
phenomena of steel manufacture, from the publication of the 
investigations of M. Fremy. In his researches, this eminent 
chemist has arrived at the conclusion, pointed to previously by 
M. Despretz, that nitrogen exercises an important influence 
over the phenomena of steeling, and that carbon plays a less 
necessary part. M. H. Caron, M. H. St. Claire Deville, and 
others, differ from M. Fremy, and still refer the formation of 
steel to the chemical combination of the iron with carbon. 
Iron ore is raised from the earth at a cost of three or four 
shillings the ton. After an outlay of thousands in the building 
