so that it
should be continuous and homogeneous throughout, without the least flaw,
seam, or crevice, required unremitting attention, as well as great
experience and skill. The welders formerly received twelve cents for
each barrel welded by them, but if, in proving the barrels, any of them
burst, through the fault of the welders, they were charged one dollar
for each barrel which failed to stand the test. This method has now,
however, been abandoned, and a much more economical and rapid process
adopted in its place. Instead of plates of two feet in length, those of
one foot are now used. These are bent around an iron rod as before; but
in place of the anvil and tilt-hammer, they are run through
rolling-machines, analogous in some respects to those by which
railway-iron is made. The scalps are first heated, in the blaze of a
bituminous coal furnace, to a white-heat,--to a point just as near the
melting as can be attained without actually dropping apart,--and then
passed between three sets of rollers, each of which elongates the
barrel, reduces its diameter, and assists in forcing it to assume the
proper size and taper. The metal by this process is firmly compacted,
becoming wholly homogeneous through its entire length.

This operation of rolling the barrel is not only a very important and
valuable one, but very difficult of acquisition, the knowledge
appertaining to its practical working having been wholly confined to one
person in this country previously to the breaking out of the Rebellion.
The invention is English, and has been used in this country but a few
years. Only one set of rollers was used at this armory until the present
emergency demanded more. About half a dozen years ago the superintendent
of the works here sent to England and obtained a set of rollers, and a
workman to operate it, bargaining with him to remain one year at a
stipulated salary. At the expiration of the time engaged for, the
workman demanded, instead of a salary, to be paid eleven cents for each
barrel rolled by him. As he had allowed no one to learn the art of
rolling the barrel in the mean time, his demand was acceded to; but
after the breaking out of the Rebellion four additional rolling-mills
were imported, and of course new men had to be taught, or imported, to
work them. The art is now no longer a secret. There are forty men
employed, day and night, running the rolling-mills, but, instead of
twelve cents, which was paid for welding, t