Manufacture of Iron and Steel Wire . 149 
inches) in height, exclusive of its parobolic arch and 
chimney. The interior of this furnace is divided into 
three parts ; the first receives the cinders ; the second is 
the fire place ; and the third receives the wire, which is 
placed between two cylinders, situated within each other, 
and made air tight. The diameter of the larger cylinder 
is about one metre four centimetres (near 55 inches) and 
that of the inner one about one metre (39.371 inches ;) 
and the fire circulates about the exterior surface of the 
former, and within the latter. Several pairs of cylinders 
are provided, in order that they may be changed every 
hour, which is effected by means of a lever, that ena- 
bles one man to draw them out or push them in at plea- 
sure. These cylinders are not opened till some time af- 
ter they are drawn out of the fire, which prevents the 
oxidation that would take place if the atmospheric air 
was admitted while the wire was hot. This new furnace 
is more expensive than that which was previously used ; 
but its advantages more than counterbalance this ex- 
pense, It is used for all wire intended for cards ; and 
the large furnace for that of a larger and harder kind ; 
but in order to diminish the formation of the oxyd, the 
bundles of wire are dipped into a quantity of wet clay, 
and then put into the furnace, and suffered to dry before 
the fire is lighted. 
These authors make use of two sorts of drawing 
plates ; large and small ; in the formation of which great 
care is necessary, as much depends upon the ability with 
which this is executed. The method they employ for 
this purpose is to put pieces of iron of a proper size and 
quality, into a furnace with cast steel, and increase the 
heat until the latter is fused ; then the iron is taken out, 
and the steel that adheres to it is amalgamated with it by 
, gentle blows. 
It is then permitted to cool, and the same process re~ 
