Yarn for Warps.
The selection of suitable yarn is obviously important. Warp yarn is generally stronger than weft, and the hardness is obtained by extra twisting of the thread: owing to this peculiarity, warp yarn is generally called “twist.” For heavy sizing purposes, a soft spun twist is advisable, and one made out of the harder and wiry stapled cottons. Brazilian is of this character, and is often mixed with American for “shirting” warps. The spongy and size-absorbent properties are obtained at the expense of the strength of the yarn, and therefore a good sizing twist often winds badly. The colour of the warp yarn is not important, and therefore whiter cottons are often reserved for weft. Fine twists are spun out of longer and finer cottons forming a close spun thread, which is used for better classes of cloth lightly sized. Strength and elasticity are great advantages in twist, and these properties should be obtained and preserved for the last process of weaving.