IMPROVED COTTON AIRPLANE FABRIC. 
atmosphere of 65 per cent relative humidity at 70° F. (21° C.) and then tested 
in this atmosphere. 
15. The distance between the jaws or clamps of the testing machine at the 
beginning of the test shall be eight (8) inches (20 cm.). The pulling jaw shall 
move at the rate of twelve (12) inches per minute during the test. 
16. The average breaking load of the five (5) specimens cut in the direction 
of the warp and the average breaking load of the five (5) specimens cut in the 
direction of the filling, as shown in figure 1, must each be at least 80 lbs. 
17. The elongation shall be observed when the sepcimens are subjected to each 
of the loads given in Table 1. 
18. Whenever practicable an autographic record shall be taken. 
19. The elongation must not exceed the values given in Table 1 by more than 
ten (10) per cent. 
20. The average results for both warp and filling shall be reported separately. 
Table 1. 
Tension 
in 
pounds. 
Elongation in 
inches. 
Warp. | Filling. 
10 
20 
70 
0. 65 0. 32 
.80 .40 
1.20 .64 
1 
21. Test for sizing. Tests for sizing shall be conducted as follows : 
(«■) Dry samples weighing approximately 0.18 oz. (5 gm.) in tared 
weighing bottles at 221 to 230° F. (105 to 110° C.) to constant 
weight. 
(6) Boil the samples in water for ten (10) minutes and rinse thor- 
oughly. 
(c) Digest each sample in a solution containing 15 cc. commercial 
diastofor in 500 cc. water at 140° F. (60° C.) for two (2) 
hours. • 
(d) Wash thoroughly in hot water and then boil for one (1) hour in 
500 cc. distilled water and wash again. 
( e ) Dry in tared weighing bottles to constant weight. 
(f) Percentage sizing- ^ ^ weight xm 
original weight 
22. The fabric must not contain more than 3.5 per cent of sizing, as determined 
by the above method. 
23. Mercerization test. Take approximately one-fourth (|) square foot, of 
the cloth, immerse in boiling distilled water, and stir occasionally while cooling. 
At the end of ten (10) minutes place a strip of blue and a strip of red litmus 
paper into the liquid with the fabric and allow them to remain five (5) minutes. 
At the end of this time the litmus papers must have retained their original colors. 
Any cloth showing either an acid or alkaline reaction shall be rejected. This 
test may be made on the yam before weaving by substituting a small handful of 
the yarn for the cloth sample. 
Inspection and eejection : 
24. The Signal Corps inspector shall mark all accepted material close to the 
end of each bolt with the official acceptance stamp. Rejected material shall be 
marked with the rejection stamp and shall not be resubmitted without the ex- 
press consent of the Signal Corps. The acceptance and rejection stamps shall 
