large roller, termed a weaver's beam, while the weft yarn has to be
prepared in suitable shape for the shuttle. These two distinct
conditions necessitate two general types of winding:

(_a_) Spool winding or bobbin winding for the warp yarns.

(_b_) Cop winding or pirn winding for the weft yarns.

For the jute trade, the bulk of the warp yarn is wound from the
spinning bobbin on to large rolls or spools which contain from 7 to
8 lb. of yarn; the weft is wound from the spinning bobbin into cops
which weigh approximately 4 to 8 ounces.

Originally all jute yarns for warp were wound on to flanged bobbins
very similar to, but larger than, those which are at present used
for the linen trade. The advent of the roll-winding machine marked a
great advance in the method of winding warp yarns as compared with
the bobbin winding method; indeed, in the jute trade, the latter are
used only for winding from hank those yarns which have been bleached,
dyed or similarly treated. Fig. 22 illustrates one of the modern
bobbin winding machines for jute made by Messrs. Charles Parker,
Sons & Co., Dundee. The finished product is illustrated by two full
bobbins on the stand and close to a single empty bobbin. There are
also two full bobbins in the winding position, and several hanks of
yarn on the swifts. Each bobbin is driven by means of two discs, and
since the drive is by surface contact between the discs and the
bobbin, an almost constant speed is imparted to the yarn throughout
the process. An automatic stop motion is provided for each bobbin;
this apparatus lifts the bobbin clear of the discs when the bobbin
is filled as exemplified in the illustration.