1868.] On the Mechanical Properties of Iron and Steel. 11 
applied a strong blast of air, which combines with the carbon at an 
intense white heat. This is continued for about eight or ten 
minutes, until the whole of the carbon is consumed, when the blast 
is stopped. In this stage a quantity of metal, containing the 
requisite percentage of carbon necessary to form the exact quality 
of the steel required, is poured into the vessel, and this combining 
with the refined iron gives to the mass all the properties and 
characteristics of steel. 
To show the facility with which the crude iron may be converted 
into refined iron or steel, the converting vessel may be placed if 
necessary so near to the blast furnace as to allow the iron to flow 
direct into it; or the metal in the shape of pig-iron may be melted 
in reverberatory furnaces, as is now generally the case, and thence 
run direct into the converting vessel. This vessel is of the shape 
shown in the Plate, supported on trunnions at a, which enable it 
to turn upon its centre and discharge its contents into a large ladle 
when the process is complete. The general apparatus will, how- 
ever, be better understood by referring to the Plate, which is a view 
of the interior of the converting house. It will be seen that two 
vessels, A A, are employed; they are placed in such a position as to 
throw the sparks and slag away from each other, and into the lower 
part of the chimneys, B B, which have hoods at B* to conduct the 
flame into them. The casting pit is semicircular in front, and 
central to it is placed the casting crane c, which supports the ladle 
into which the steel flows, and from which it is delivered through a 
cone valve, a, at the bottom of the ladle. One of the vessels is 
shown in section in the act of pouring out the fluid steel into the 
ladle, while in the other the process of conversion is going on. 
When necessary both vessels may be worked at the same time, and 
their contents poured into one large ladle, so that an ingot of 20 
tons may be made from what is usually styled a 10-ton apparatus. 
It will be observed that the hydraulic casting crane, c, is brought 
so far from the line formed by passing through the centres of the 
converting vessels as to allow one vessel to be moved round if 
necessary, while the ladle is in front of the other vessel. This 
position of the crane enables the casting pit to be made larger, and 
gives more space for the moulds. 
In the act of pouring the steel from the converter into the 
casting ladle, the crane is steadily lowered and its bend moved 
round to accommodate the curved path in which the spout of the 
converting vessel moves. This lowering of the crane is effected by 
a boy on the valve stand, which is situated at a distance of about 
twenty feet from the casting pit, and in a line with the centre of 
the casting crane. On this stand the cocks for the moving of the 
vessel are placed; here also are the handles of two large balanced 
air-valves by which the blast is regulated. 
