12 BULLETIN 591, U. S. DEPARTMENT OF AGRICULTURE. 
TABLE V.—Tensile-strength comparisons of 22’s yarn in pounds per skein of 120 yards 
each (textile-school tests). 
i Aver- 
Zone. M.F. |} G.M. M. L.M. | G. O. age. 
2 } 71.9 73.4 70.0 64.0 70.0 
IPicdmontrelateateecas-a sees Se eee eee a < h 73.2 75.6 74.7 69. 2 73.3 
7 70.0 71.3 68.3 64.7 68.8 
INAV) ys SS ae ee ee Pe nes 3 es Se fs TUS? 73.4 71.0 66. 0 70.7 
: 3 5 owk 70.5 68. 4 68. 2 71.3 
AtionticiCostal PlaMSanc- eos -eetcee nese eee : : 77.3 73.4 69.6 69. 2 73.4 
: 74.7 70.4 67.2 67.5 70.7 
PANVOTARO ites cae oe eee nae Ce eee is 75.7 71.4 68. 4 68.3 71.8 
70.3 68.1 8.5 63.5 68. 6 
Eastern Gulf Coastal Plains................-- 76.8 71.7 78h 7 65.1 73.0 
73.0 68. 6 69. 6 63. 4 69.5 
ERVETAPO oc cok Sac Me CON) Perak ears : 73.4 69. 5 70.6 64.0 70.4 
Average of easterm stock -..--.....-..-..-----. 6] 73.6 71. 4 70. 0 66.1 71.0 
F : 74.7 77.6 66.8 69.9 75. 5 
Western Gulf Coastal Plains.................. : if 75.3 78. 2 67.6 72.5 75.8 
72.6 75.8 67.5 68. 2 73.1 
AV CTA RC nice sree He ate coe nee aoee eee é 74.2 77.2 67.3 70. 2 74.8 
Western Prarie Lands and Plateau 
PAS CLA? C aera eee sean iQaene IpGHS ee ase : 84.8 81.9 74.6 76.0 79.5 
Average of western stock ---........----|...----- : 79.5| 79.6| 71.0] 73.1 77.2 
The variations in the tensile strength of yarn made from cotton 
originating in the Piedmont Plateau, Atlantic Coastal Plas, and 
eastern Gulf Coastal Plains conform closely to the grade of the cot- 
ton, but the tensile strength of yarn made from cotton originating in 
the western Gulf Coastal Plains or western Prairie Lands and Plateau 
does not bear the same relationship to the grade. The same rela- 
tionship in the tensile strength of Low Middling and Good Ordinary 
is shown as in the tensile strength of yarn made from the same grades 
of western upland cotton in the mill tests. (See Table IIT and dis- 
cussion on p.6.) Cotton from crops of several seasons must be tested 
before a safe basis for comparison can be established. - 
It will be observed also that in the textile-school tests the twist 
constant 4.76, which was the nearest obtainable to 4.75, known as 
the twist standard for upland cotton of approximately 1-inch staple, 
did not produce yarn with a maximum tensile strength. The average 
tensile strength of the five grades in the different zones shows that 
the constant 4.53 produced stronger yarn than either 4.76 or 4.29. 
Constants 4.29, 4.53, and 4.76 represent, respectively, 20.12, 21.25, 
and 22.32 turns per inch for twist for 22’s yarn. Practically the 
same results were found in the mill tests. (See Table III.) The 
twists per inch in the yarn were verified by untwisting the yarn and 
counting the turns per inch. 
