l filling is employed, with a view to lay two picks nicely
side by side, whereas a thread entered two ply with the taffeta weave will
always receive some twist, which may disturb the perfect evenness of the
fabric.

Fig. 18 is a Gros de Tours with two picks on four harness straight through.

Fig. 19 illustrates this weave with three picks drawn end and end on two
sections of four shafts each.

* * * * *

[Page 20]
SERGE or TWILL WEAVES

While the taffeta weave produces either an entirely smooth fabric, or one
with a distinct transverse rib as in gros-grain, the twill weave forms
diagonal lines on the cloth, running either from left to right or from
right to left.

To make a twill, not less than three ends and three picks are required, of
which each thread floats over two of the other system and interlaces with
the third. The rotation of the interlacing is always consecutive, that is
it moves with each succeeding pick one thread to the right (or to the left
if the lines are to run in that direction). If warp and filling have the
same texture, that is the same number of threads in a given space, the
twill lines will form an angle of 45 deg.; if the warp stands closer than the
filling, the incline will be steeper, and in the opposite case the angle
will approach more the horizontal.

The weaves can be expressed in numbers, for instance: the 3-end twill warp
effect would be marked 2-1, which indicates that each warp-thread goes over
two and under one pick.

Twill weaves are called _evensided_ when the arrangement of "warp up" and
"filling up" are evenly balanced, and _unevensided_ if either warp or
filling predominate on the face of the fabric; the latter class is
therefore subdivided in _Warp effects_ and _Filling effects_.

In the following a number of serge weaves are illustrated, the French
designations being added in some cases, as they are still extensively used
in the trade.

[Page 21]
* * * * *

FILLING EFFECTS

_Satin de Lyon,_ 2-1.

On 6 harness straight through.

[Illustration: Fig. 20]

* * * *

_Levantine,_ 3-1<h/5>

On 8 shafts skip draw.

[Illustration: Fig. 21]

* * * *

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