MANUFACTURING TESTS OP COTTON 
17 
signs), dividing this result by the average break and then multiplying 
by 100 (method 2). The percentage of extreme variation is deter- 
mined by subtracting the minimum from the maximum and dividing 
by the average break and then multiplying by 100 (method 2). 
Similarly, the irregularity of the size or number of the yarn may be 
determined. (See Tables 6 and 7 for data.) Method 1 has some 
advantage over method 2, for the reason that the results may be 
more readily grasped from a graph than from a table of figures. 
STRENGTH 
IN OUNCES 
SINGLE 
STRAND TEST 
m 
23 
21 
21 
20 
I 9 
IS 
I 7 
I 6 
I 5 
• 
• 
/ 
\ 
• 
• 
• 
• 
• 
• 
/ 
• 
• 
• 
/ 
• 
• 
• 
• 
• 
\ 
• 
i 
• 
• 
• 
4 
/ 
• 
1 
Bleached 
and Mercer 
~i- 
••■ 
/ 
• 
• 
• 
/ 
"*•••*». 
•**.. 
Gray -v, / 
-> 
/ 
// 
S 
/ I 
/ / 
"\ 
\ 
/ 
// 
A 
/ Bleac 
hed (Single) 
N 
/ 
*N 
1 
• 
/ 
987654321 
GRADE NUMBERS 
Fig. 10. — Strength in ounces per single strand as determined by 32 observations of each grade of 
28s two-ply yarn spun from western upland cotton. (21.1 turns per inch in yarn.) The mercer- 
ized yarns were stronger than the gray and the gray yarns were stronger than the bleached 
except on grade No. 3 
The results of these calculations indicate that there is no definite 
relation between the grade and the uniformity of the 22s yarn. 
Averaging the nine grades together (method 2) gave the results 
shown in Tables 9 and 10. These figures indicate that this par- 
ticular double bleach caused the yarn to become more irregular. 
