216 STEEL, AND THE BESSEMER PROCESS. 
nozzles, &c, and in more convenient access to ovens and depositories of 
fire materials. 
But the grand American improvement in the Bessemer process is the 
adaptation of the cupola for melting the iron. In the reverberators a 
pound of best bituminous coal will melt but two pounds of iron. In 
the cupola a pound of best anthracite will melt from seven to ten 
pounds of iron. The sulphur, if any, communicated by melting with 
"best anthracite, has not been discoverable in working some fifty tons of 
the material into boiler plates, rivets, pistol and rifle steel, and other 
forms that put its malleability and soundness to the severest tests. The 
structure and arrangement of the cupola, to better adapt it to this 
particular service, is the subject of experiments now going on at Troy. 
It is expected that from nine to twelve charges of steel, of from five to 
seven tons each, will be made per day. In the old works four charges 
have been made per twelve hours. 
The Bessemer process is, to the casual observer, almost ridiculously 
simple. It is, in fact, very simple ; and it is conducted without any 
risk or difficulty, always providing that the iron used is of good quality, 
as most American iron is. Indeed, it is almost impossible to make bad 
steel, or steel that is not uniform, out of good uniform iron, if ordinary 
attention is paid to the manufacture and the machinery, because the 
quality of the steel is not in a great degree dependent on the skill or 
judgment of the operator. The ingredients are mixed by weight. 
Bessemer steel cannot be economically made, however, without first-rate 
blowing machinery, good and convenient apparatus, and constant vigi- 
lance on the part of two or three skilled operatives who have charge of 
the tuyeres and linings. 
The great commercial advantage of the Bessemer process over all 
other steel processes, and considering the quality of the product, over 
puddling, is its cheapness. The only fuel used is that for melting the 
pigs in a cupola, for heating the converter at the commencement of a 
series of charges, and the small amount for heating ladles, &c. The 
fire material costs something more than in iron-making. The pig-iron 
required is more expensive than the average irons used in puddling. 
Very little skilled labour is required. Some steel products are produced 
at about the cost of wrought-iron products of the same shape and 
weight. 
The grand advantage of Bessemer steel over wrought-iron, especially 
in large masses, is its perfect homogeneity — the absence of welds and 
consequent imperfections, such as the laminations in rails, blisters in 
boiler plates, and cold -shuts in heavy forgings. Its tenacity is double 
that of wrought-iron, considering the above-mentioned and unavoidable 
defects of wrought-iron in welded masses. In the bar it is one-half 
greater than that of wrought-iron, or from 90,000 to 120,000 lbs. per 
square inch, according to the degree of carbonisation required for different 
purposes. The nature of the Bessemer process renders the product more 
