son machines now shown, the needle bars consist really of
steel tubes. Small moving parts are made as light as possible, but rigidity
is secured by the free use of strengthening ribs. Many of the parts are of
cast iron, rendered malleable by annealing, and finally casehardened. Such
parts are found to be quite as durable as if made of forged steel, and are,
of course, less costly. As to the automatic tools now used in the
construction of the machines, it may be said that scarcely a file, hammer,
or chisel touches the frame or parts while they are being assembled to work
together. The interchangeable system of construction is, of course, the
only one possible for the accurate production of the millions of sewing
machines now manufactured annually.

_High Arm Construction_.--Sewing machines, as now constructed, exhibit a
rather short and very high arm, a form of framework that has been found to
contribute in no small degree to the light running capabilities of fast
speed machines. While it reduces the length of the various parts concerned
in the transference of the motive power, it adds to their rigidity and
diminishes their weight, maintaining at the same time the capacity of the
machine to accommodate the largest garments beneath the arm.

But the specific improvements in plain sewing machines, to which I have had
the honor of drawing your attention, do not exhaust the list, and, time
permitting, it might be considerably augmented. Nor must it be inferred
that advancement has taken place exclusively in those systems of sewing
machinery now before us.

_Accessories to Sewing Machines_.--The number of special attachments that
have been successfully adapted to plain sewing machines has multiplied so
rapidly of late, that only one or two of the more notable can be spoken of
on this occasion. Perhaps the most generally useful of these is the
trimmer, an arrangement consisting of a vibrating knife, which trims off
the superfluous edge of a seam as the machine stitches it. These are in
extensive use in the factories at Leicester, Nottingham, and elsewhere,
while Northampton and Norwich use the same device for paring the seams in
boot upper manufacture. The chisel-like knife is usually actuated by a cam
rotating with the main shaft, and one or two of the usual forms of this
attachment are to be seen here this evening on both lock and loop stitch
machines.

When machines are moved by the foot, there are many objections to runn