Fan. 12, 1871 | 
NATURE 
2II 
ee 
PAPERS ON IRON AND STEEL 
No. Il.—THE BESSEMER PROCESS. 
‘ie this paper I propose to describe the general phe- 
nomena of the Bessemer process, and then to 
examine the chemical actions producing these phenomena 
and the changes they effect in the material operated 
upon. 
In the first place the pig-iron is melted in a suitable 
furnace, usually in that form of furnace known as the 
“cupola.” The melted iron is run from this by means of 
moveable troughs into the “ converter,” which is a pear- 
shaped spouted vessel, lined with fire-clay, “ ganister,” or 
other refractory substance. 
This pear-shaped vessel, a vertical section of which in 
the upright position and without mechanical details is 
represented in the annexed figure, is truncated at the 
Jower end, and thus a flat circular bottom is formed. This 
bottom, which is readily detached and renewable, is fitted 
with longitudinally perforated fire-clay cylinders shown in 
section at cd, cd, cd, ci’, each perforation or clay tube being 
about one-half or three-quarters of an inch in diameter, 


















and all communicating with the space @ d, into which 
opens the blast tube from a powerful blowing engine. The 
number of these blast holes varies from fifty or sixty to a 
hundred or more, according to the size of the converter. 
The converter is mounted on trunnions so arranged 
that it may turn on a transverse axis crossing about the 
middle of the vessel, as shown by the dotted circle 0. The 
turning is effected by hydraulic machinery, controlled by | 
levers readily worked by a man who stands on a platform | 
in full view of the converter. In order to receive the 
charge of melted iron, the converter (the lining of which 
has been previously raised to a bright red heat) is turned 
over so that the dotted line e f becomes horizontal, and 
corresponds to the surface ofa full charge. The belly ¢ 
of the converter is so curved that it shall in this position 
retain the whole charge without any of it reaching the 
blast holes at /, or the inouth at e¢, and yet allow the whole 
charge to be readily “teemed” by turning the converter 
a little further down. j F 
When the full charge is thus received in the belly of the 
converter, the blast is turned on, after which the converter 
is turned to the upright position, as shown in the figure, 

| 
and the melted metal then stands directly over the per- 
forated bottom. As wi'l thus be seen, all the fluid metal 
above the openings is now resting upon a bed of air, and 
is only prevented from falling through by the blast being 
maintained at a pressure exceeding the falling force of the 
column of liquid above it. It would fall through these 
orifices into the blast-way and do serious mischief should 
the blast be stopped or slackened for an instant, or should 
the converter be turned upright or overcharged before the 
commencement of the blast. An accident of this kind 
but rarely happens, though it is by no means an unknown 
casualty. 
The “ blow,” as it is termed, now commences ; the hun- 
dred streams of air tear through the pool of melted iron, 
and a huge flame roars furiously from the mouth of the 
converter. At irregular intervals magnificent cascades of 
brilliant coruscating sparks are belched forth, and the 
dazzling spray as it dashes against the walls of the flame- 
shaft rebounds with redoubled splendour, each glowing 
globule being shattered by the shock and bursting into 
rescintillating fragments. The loud-bellowing blast roars 
on monotonously, but the flame becomes brighter and 
brighter continuously, and grows in length and breadth as 
it increases in brilliancy, until at the end of about ten 
minutes it attains its maximum, when its splendour is 
painful to the eye, and yet so fascinating that few who see 
it for the first time can turn their dazzled eyes away. The 
spark eruptions still burst upwards from time to time, and 
still dash against the brickwork and the ground, and still 
reverberate in fiery splinters, but their appearance has 
changed. They are now no longer red hot, or yellow hot, 
or white hot, but have a curious purple luminosity different 
from anything one has ever seen before. If it is daytime 
and the sun shining, the sunlight out of doors has a 
sickened partial-eclipse aspect when viewed directly after 
gazing at the flame, and at night the ordinary gas lights 
appear red and smoky. 
After five or ten minutes’ continuance of this maximum 
splendour, the flame is seen to contract somewhat, and 
presently the ponderous vessel turns a very deliberate 
summersault, the flame disappears, but the uninitiated 
spectator is startled by a new display ; for as the converter 
rolls smoothly over, it disgorges a continuous stream of 
sparks which its rotation spreads out in a fan-shaped 
volley, extending from end to end of the building, and 
reaching the roof, descends in a broad sheet of fiery hail. 
This is the transformation scene which concludes the first 
part of the performance ; for now the dazzle of the flame 
and the roar of the blast ceases, and a general lull inter- 
venes. 
The trough from the cupola is now swung round to the 
mouth of the converter, a red glow is seen to creep alone 
it, and starry sparks dance above as it advances. This 
is the spiegelcisen coming from its cupola by the same 
path as conducted the main charge. The spectator 
should now change his position, and if possible find a 
standing place from which he may look into the 
mouth of the converter. At first he will distinguish 
nothing but a yellow glare, but by steadily fixing his gaze, 
he will presently, and rather suddenly, distinguish the 
surface and limits of the pool of melted metal. He will 
see that as the spiegeleisen pours into it, a furious ebullition 
takes place. At the same time a great mass of pale blue 
flame issues from the mouth of the converter, but with a 
quiet, leisurely waving that contrasts curiously with the 
previous roaring jet of white flame. This flame has but 
very little intrinsic luminosity, yet at night it lights up all 
the surrounding objects with a singular brilliancy, a sort 
of exaggerated theatrical moonlight effect, which is the 
most remarkable to a spectator outside, who on a misty 
night sees the long streams of ghostly light pouring 
through every opening of the building in pallid beams, 
that under favourable conditions may be traced for above 
a quarter of a mile. I have seen them projected in bright 
