has a Barber knotter on
her hand_]
The yarn of the warp must usually be impregnated with a sizing which will
smooth out and stick down its furry surface and add as well to the
tensile strength so that the strain of weaving may be withstood. For this
the most effective and most generally used machine is the slasher, the
chief feature of which is a roller, whose lower side is immersed in the
sizing solution. Threads from the warp beam are run around this roller
through the solution and then dried, after which it is finally wound on
another beam for the loom. A considerable number of loom beams can be
filled from one set of the warper beams mounted in the slasher.
The lengthwise threads of a fabric are called the warp. The crosswise
threads are called the weft or filling. To make cloth, the warp and weft
must be interlaced with each other in a suitable manner. The operation is
called weaving, the machine in which it is performed is, of course, the
loom. The principal operations of weaving are as follows:
1. Shedding, or the raising and lowering of the alternate threads
of the warp, so that the weft may pass under and over them.
This is done by means of the harnesses and their heddles.
2. Picking, or placing a thread of the weft between the warp
threads so raised and lowered by means of the shuttle.
3. Beating-up, or pushing, each thread of the weft into its
position close against the thread which has preceded it by
means of the reed.
4. Letting-off, or permitting the warp to unwind from the beam only
just as fast as is needed by the speed of the weaving. This is
accomplished by friction bands and weights on the warp beam.
5. Taking-up, or winding upon a roller the cloth as it is
manufactured.
In addition to these primary operations, the loom has attachments for
performing several other functions, such as stop-motions for stopping the
loom when warp or filling threads break, or when the shuttle fails to
cross the loom completely; temples for holding out the cloth laterally as
the weaving proceeds; a mechanism--in the most modern looms--for changing
the shuttles, or the cops in the shuttles, as the weft thread on the cops
becomes exhausted, etc.
[Illustration: _Diagram of ring spindle_]
The modern cotton loom, which automatically removes the filling bobbins
without stopping the loom, is rapidly displacing the older types, and one
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