4 



BULLETIN 946, U. S. DEPARTMENT OF AGRICULTURE. 



The greater part of this difference in waste occurred at the pickers 

 and cards, and may be partly accounted for by the lower grade of 

 the Meade selected for the test. 



On averaging the results of the tests for the three seasons, it was 

 found that on the pickers, the Meade cotton was 0.82 per cent more 

 wasty than the Sea Island ; on the cards, 1.40 per cent ; on the combers, 

 1.94 per cent ; and for all three processes, 3.50 per cent. The differ- 

 ence on the comber could be eliminated by slight adjustments of this 

 machine, so that the difference in the wastiness of the two cottons 

 might be reduced to an almost negligible amount. 



BREAKING STRENGTH OF YARN. 



Both growths of cotton were spun into 23's, 40's, 60's, 80's, and 

 100's yarn. Each number of yarn was produced with three different 

 twists, namely those indicated by the twist multipliers 3.25, 3.50, 

 and 3.80. That is, these figures multiplied by the square root of the 

 number of yarn being spun give the turns of twist per inch in the 

 yarns. The results of the twist tests were not conclusive in that they 

 show some cases in which the strength of the yarn increased on 

 changing the twist multiplier from 3.5 to 3.8, and other cases in 

 which the strength decreased with the greater twist. The same facts 

 were evident when the twist multiplier was changed from 3.5 to 3.25. 



A comparison of the breaking strengths of the Meade and Sea 

 Island cottons is shown in Table 2, in which the breaking strength 

 in pounds per skein of 120 yards for the various numbers of yarn 

 having a twist equal to 3.5 times the square root of the number of 

 yarn is given. 



Table 2. — Breaking strength, in pounds, per skein of 120 yards of various sizes 

 of yarns spun from Meade and Sea Island cotton grown in different seasons. 



(3.50 twist multiplier used.) 



Season. 



Size of 

 yarn. 



Meade cotton. 



Sea 

 Island 

 cotton. 



1910-17 



1918-19. 



/23's 



\100's 



f23's 



10's 



eo's 



80's 



100's... 



129.7 

 15.2 



109.2 

 60.1 

 35.4 

 24.1 

 16.3 



1919-20. 





Sandy soil. 





103.8 



40's 



54.6 



60's 



33.7 



80's 



22.6 



[100'S.... 



15.5 



Clay soil. 

 107. 69 

 53.5 

 30.7 

 19.6 

 12.8 



144.7 

 17.4 



128.7 

 69.8 

 39.4 

 25.9 

 17.6 



122.6 

 58.5 

 34.8 

 22.3 

 15.6 



During the seasons of 1916-17 and 1918-19, when the Meade and 

 Sea Island cottons were grown under normal conditions, the break- 

 ing strength of the yarns spun from Meade cotton was weaker than 



