602 
MANUFACTURE OF IRON AND STEEL. 
for running in the crude metal, and on the opposite side there 
was a tap-hole stopped with loam, by means of which the 
iron was run out at the end of the process. The vessel should 
be placed so near to the discharge-hole of the blast furnace 
as to allow the iron to flow along a gutter into it. A small 
blast cylinder would be required, capable of compressing air 
to about 8 lb. or 10 lb. to the square inch. A communication 
having been made between it and the tuyeres before named, 
the converting vessel would be in a condition to commence 
work. It would, however, on the occasion of its being first 
used after re-lining with fire-bricks, be necessary to make a 
fire in the interior with a few baskets of coke, so as to dry 
the brickwork and heat up the vessel for the first operation, 
after which the fire would have to be all carefully raked out 
at the tapping-hole, which would again be made good with 
loam. The vessel would then be in readiness to commence 
work, and might be so continued without any use of fuel, 
until the brick lining in the course of time became worn 
away and a new lining was required. The tuyeres are situated 
nearly close to the bottom of the vessel ; the fluid metal will 
therefore rise some eighteen inches or two feet above them. 
It is necessary, in order to prevent the metal from entering 
the tuyere-holes, to turn on the blast before allowing the fluid 
crude iron to run into the vessel from the blast furnace. 
This having been done, and the fluid iron run in, a rapid 
boiling up of the metal will be heard going on within the 
vessel, the metal being tossed violently about, and dashed 
from side to side, shaking the vessel by the force with which 
it moves from the throat of the converting vessel. Flame 
will then immediately issue, accompanied by a few bright 
sparks. This state of things will continue for about fifteen or 
twenty minutes, during which time the oxygen in the atmos- 
pheric air combines with the carbon contained in the iron, 
producing carbonic acid gas, and at the same time evolving 
a powerful heat. Now, as this heat is generated in the 
interior of, and is diffused in innumerable fiery bubbles 
through, the whole fluid mass, the metal absorbs the greater 
part of it, and its temperature becomes immensely increased : 
and by the expiration of the fifteen or twenty minutes before 
named, that part of the carbon which appears mechanically 
mixed and diffused through the crude iron has been entirely 
consumed. The temperature, however, is so high that the 
chemically-combined carbon now begins to separate from the 
metal, as is at once indicated by an immense increase in the 
volume of flame rushing out of the throat of the vessel. The 
metal in the vessel now rises several inches above its natural 
