therefore, one of the original pieces of iron has any flaw or defect, it
will form only a hundred and twelfth part of the thrice-rolled bar. The
uniformity of texture and the toughness of the bars which have been
thrice rolled are so great that they may be twisted, cold, into a knot
without showing any signs of fracture. The bars of iron, whether hot or
cold, are sawn to the various required lengths by the hot or cold saws
shown in the illustrations, which revolve with great rapidity.

[Illustration: FURNACE AND HYDRAULIC DIE.]

For the columns intended to sustain the compressive thrust of heavy
weights a form is used in this establishment of their own design, and to
which the name of the "Phoenix column" has been given. They are tubes
made from four or from eight sections rolled in the usual way and
riveted together at their flanges. When necessary, such columns are
joined together by cast-iron joint-blocks, with circular tenons which
fit into the hollows of each tube.

To join two bars to resist a strain of tension, links or eye-bars are
used from three to six inches wide, and as long as may be needed. At
each end is an enlargement with a hole to receive a pin. In this way any
number of bars can be joined together, and the result of numerous
experiments made at this establishment has shown that under sufficient
strain they will part as often in the body of the bar as at the joint.
The heads upon these bars are made by a process known as die-forging.
The bar is heated to a white heat, and under a die worked by hydraulic
pressure the head is shaped and the hole struck at one operation. This
method of joining by pins is much more reliable than welding. The pins
are made of cold-rolled shafting, and fit to a nicety.