MANUFACTURING TESTS OF COTTON 
15 
IRREGULARITY OF YARNS 
The specifications for the .purchase of yarns are usually based 
upon the average strength and size. The average strength alone, 
however, is not always a true index of the quality of the yarn. Two 
yarns may have the same average strength but differ in uniformity. 
There are several methods of determining the irregularity of yarns, 
two of which are used herein: (1) Plotting the range of strength 
STRENGTH 
IN OUNCES 
SINGLE 
STRAND TEST 
13 
12 
10 
6 5 4- 
GRADE NUMBERS 
Fig. 8. — Strength in ounces per single strand of 22s gray and treated warp yarns spun from the 
western upland cotton. (21.1 turns per inch in yarn.) The gray yarn is stronger than the 
treated yarns. The double bleach has decreased the strength of the yarn from that of the single 
bleach 
from the corrected breaks, and (2) calculating the percentages of 
average deviation and extreme variation of the breaks. 
» 
22s WARP YARN (SKEIN) 
Figures 11 and 12 show graphically the irregularity of the skein 
break of the 22s single yarn spun from the eastern and western cottons 
respectively (method 1). This irregularity is indicated by the angle 
the curve makes with the horizontal — the greater the angle of the 
curve, the more irregular the yarn, the smaller the angle, the more 
uniform the yarn. The percentage of extreme variation of the cor- 
rected breaks, represented by any one of the curves on Figure 11 or 
