When iron is simply melted and run into any mould, its texture is
granular, and it is so brittle as to be quite unreliable for any use
requiring much tensile strength. The process of puddling consisted in
stirring the molten iron run out in a puddle, and had the effect of so
changing its atomic arrangement as to render the process of rolling it
more efficacious. The process of boiling is considered an improvement
upon this. The boiling-furnace is an oven heated to an intense heat by a
fire urged with a blast. The cast-iron sides are double, and a constant
circulation of water is kept passing through the chamber thus made, in
order to preserve the structure from fusion by the heat. The inside is
lined with fire-brick covered with metallic ore and slag over the bottom
and sides, and then, the oven being charged with the pigs of iron, the
heat is let on. The pigs melt, and the oven is filled with molten iron.
The puddler constantly stirs this mass with a bar let through a hole in
the door, until the iron boils up, or "ferments," as it is called. This
fermentation is caused by the combustion of a portion of the carbon in
the iron, and as soon as the excess of this is consumed, the cinders
and slag sink to the bottom of the oven, leaving the semi-fluid mass on
the top. Stirring this about, the puddler forms it into balls of such a
size as he can conveniently handle, which are taken out and carried on
little cars, made to receive them, to "the squeezer."

[Illustration: THE ROLLS.]

To carry on this process properly requires great skill and judgment in
the puddler. The heat necessarily generated by the operation is so great
that very few persons have the physical endurance to stand it. So great
is it that the clothes upon the person frequently catch fire. Such a
strain upon the physical powers naturally leads those subjected to it to
indulge in excesses. The perspiration which flows from the puddlers in