Each of these cans of drawn sliver is then taken to a slubbing machine, which draws out the sliver still more. This machine has spindles which twist and wind the material on to bobbins.
The bobbins are now placed on a roving frame, where the thread—now referred to as a “roving”—is further drawn out, twisted, and wound on to smaller bobbins. These small bobbins then go to a fine roving frame, where the process is repeated. Each successive machine delivers a finer roving than it receives, and after the final roving the bobbins are taken to the spinning frame, where they are mounted, and the strands of cotton receive their final drawing. The spinning ring on the frame gives the cotton the necessary twist, and it now becomes yarn. The more twist that can be imparted to the thread during spinning, the firmer the yarn becomes.
Lisle. This is a hard, twisted cotton yarn—sometimes of the Sea Island type—having a twist (or turn) per inch higher than that put into ordinary cottons. The yarn is a two-ply, one thread has a right-hand, and the other a left-hand twist, and the two threads are finally twisted together. Because of its high twist, lisle is strong, and fine counts of yarn are obtainable, the thread having plenty of resilience, and possessing cool, absorbent, and evaporating qualities. Because of the additional process of twisting, lisle yarn is more expensive than ordinary cotton.
Mercerised Lisle is a yarn processed exactly as lisle except that the cotton is chemically treated. While under tension in a solution of caustic soda, the fibres are stretched, and swelling out, they regain their original tubular shape, this enabling the light to be reflected more readily, resulting in an appearance of lustre. This process is called “Mercerising”—after its inventor, John Mercer.
Mercerised lisle is largely used for reinforcing the heels and toes of stockings so as to give extra strength at these points of wear. (See Chapter 10.) This yarn is also used in the manufacture of Fine-Gauge