COTTOX PRICES AND MARKETS / 
valuable for spinning purposes than cotton which has no predomi- 
nating length of fiber. Cotton that lacks uniformity is said to be 
"wasty," which means that many short fibers must be removed be- 
fore it spins satisfactorily. 
THE GRADE 4 
The number of pounds of yarn made from a given bale is deter- 
mined largely by the grade and humidity of the cotton and the uni- 
formity in length of the fibers. The higher grades of good charac- 
ter have comparatively little waste, but waste makes up an appre- 
ciable part of the weight of a low-grade bale of poor character. 
Waste may be either visible or invisible. Invisible waste has no 
value and consists of such things as loss of moisture, dust, and short 
fibers which are lost in the air. Visible waste consists of trash and 
dirt which have little or no value ; and motes, neps, and short fibers, 
which have some value. Thus, with the same set of machinery it 
takes longer to run a bale of 500 pounds of low-grade cotton through 
the mill than a high-grade bale of the same weight, and at the end 
of the process the spinner has fewer pounds of a less valuable article. 
The machines must be run slower and must be cleaned oftener, and 
the thread breakage increases in the lower grades. In spinning tests 
conducted by the United States Department of Agriculture in co- 
operation with textile schools and private mills, it was found that 
the breakage on the spinning frame (not due to mechanical defect) 
was 12.1 per cent of the number of threads in the Middling Fair 
grade, 13.8 per cent in the Good Middling, 14.4 per cent in the Mid- 
dling, 27.5 per cent in the Low Middling, and 32.2 per cent in the 
Good Ordinary. 
The value of yarn from high-grade cotton is greater than the 
value of yarn from the lower grades, because of its comparative ten- 
sile strength. The breaking strength in pounds per skein 5 of yarn 
is shown in Table 8. 
Table 8. — Comparative tensile strength of 22s yarns from specified grades of 
Upland cotton in pounds per skein of 120 yards a 
Eastern Upland 
Western Upland 
Twist con- 
stant b 
Mid- 
dling 
fair 
Good 
mid- 
dling 
Mid- 
dling 
Low 
mid- 
dling 
Good 
ordi- 
nary 
Av- 
erage 
Mid- 
dling 
fair 
Good 
mid- 
dling 
Mid- 
dling 
Low 
mid- 
dling 
Good 
ordi- 
nary 
Av- 
erage 
4.20 
4.54 
4.74 
Lbs. 
75.9 
75. 7 
74.1 
Lbs. 
76.0 
76.4 
75.8 
69.8 
Lbs. 
75.2 
74.4 
70.5 
69.8 
Lbs. 
72.3 
73.1 
71.0 
69.6 
Lbs. 
70.4 
67.5 
68.4 
67.6 
Lbs. 
74.0 
73.4 
71.6 
Lbs. 
84.1 
86.3 
82.4 
Lbs. 
85.7 
82.1 
79.0 
Lbs. 
83.7 
82.3 
79.1 
78.5 
Lbs. 
72.2 
73.3 
69.7 
69.1 
Lbs. 
76.6 
75.9 
75.1 
71.9 
Lbs. 
80.5 
80.0 
77. 1 
4.95. . 
72.5 
69. 9 1 82. 7 1 78. 9 
76 2 
Average 
74. 6 i 74. 5 | 72. 5 
1 1 
71.5 
68.0 
72.2 
83.9 J 81.4 
80.9 
71.1 
74.9 
78.4 
Adapted from Department Bulletin 591, United States Department of Agriculture, page 6. 
° As shown by mill tests. 
* Twist constant 4.75 is considered as standard for warp yarns, Upland cotton. The twist per inch in 
serted in the yarn will be found by multiplying the square root of the number of yarns by the twist con- 
stant. 
* See also p. 62. 
5 In commercial practice, the strength of yarn is determined by winding a skein of 120 
yards (80 rounds on a 1%-yard reel) and breaking this skein on a standard strength- 
testing machine. 
