IMPROVED COTTOK AIRPLANE FABRIC. 
11 
Table 6. — Weight, breaking strength, and stretch of 2/60's, 80 by 80, plain-weave 
fabric made from mercerized yarn, (Twist multiple of 4 used in the single 
and ply yarn.) 
Ounce 
per 
square 
yard. 
Strength in 
pounds. 
Stretch in inches at different loads. 
Warp. 
2/60's. 
Warp. 
Filling. 
Fining. 
10 
pounds. 
20 
pounds. 
70 
pounds. 
10 
pounds. 
20 
pounds. 
70 
pounds. 
American Egyptian 
4.23 
87 
98 
90 
85 
89 
100 
99 
91 
0.53 
.32 
.40 
.48 
0.75 
.49 
.61 
.66 
1.20 
.83 
1.00 
1.03 
0.19 
.20 
.18 
.19 
0.30 
.27 
.27 
.29 
0.62 
Sakellaridis high grade 
Sakellaridis lower grade 
Sea Island 
4.15 
4.22 
4.00 
.50 
.51 
54 
By comparing the combined strengths of the warp and filling as 
given in Tables 5 and 6, it was found that in the 3/80's cloth the 
breaking strength of the high-grade Sakellaridis was 10.7 per cent 
greater than that of the American Egyptian and 5.4 per cent greater 
than that of the Sea Island. However, in the 2/60's fabric the break- 
ing strength of the high-grade Sakellaridis was 12.5 per cent greater 
than that of either the American Egyptian or the Sea Island, the 
latter two, as in the case of the yarns, being equal in strength. 
The results of the tests as to stretch as shown by Tables 5 and 6 are 
not conclusive. 
VARIATION OF TWIST. 
Having compared the three varieties in regard to strength and 
stretch, using the mill's twist multiple of four, the effect of varying 
the twist in the single and three-ply yarns was investigated. Single 
80's were spun from the American Egyptian cotton with twist mul- 
tiples x varying from 3.39 to 4.27. In plying a part of the 80's yarn 
the same multiple was used as had been used in spinning the cor- 
responding single yarn. The remaining 80's yarn was plied to give 
approximately two turns more or less twist than this basis, thus pro- 
ducing 3/80's yarns of different twists from which selections could 
be made. After carefully determining the size and tensile strength 
•of the yarns made with each different twist multiple, the strongest 
ply yarn was found to result from a combination of 3.83 twist mul- 
tiple in the singles with 3.63 in plying. The results of these tests 
are shown in Table 7. 
1 A twist multiple is an arbitrary number by which the square root of the hank or 
size of the yarn is multiplied. The product thus obtained shows the twist per inch in 
the resulting yarn. 
