6—DIMENSIONAL RELATIONS IN UNSTRAINED AND STRAINED WOOL FIBRES

The cross-sectional area, ellipticity, and ‘natural-twist’ variations are given for different types of pen-grovvn wool fibres, and it is shown that large changes may take place over short lengths. Measurements on stretched fibres have shown that the stretching process is complex. There is evidence to indicate that equal cross-sectional areas do not necessarily behave similarly. During stretching, a large amount of redistribution and removal of natural twist takes place. It is shown that thinner sections twist more than thicker sections and that it is easier to twist the fibre against the direction of natural twist.