BULLETIN 359, U. S. DEPARTMENT OF AGRICULTURE. 
Table VII. — Average breaking strength of single threads arranged in order, for comparison 
according to grade relations. 
[With twist per inch as indicated by the twist constant.] 
Twist constant. 
Num- 
bers of 
yarn. 
Extra 
Ari- 
zona. 
Fancy 
Sea 
Island. 
Choice 
Ari- 
zona. 
Extra 
choice 
Sea 
Island. 
Good 
Sakel- ' 
laridis. 
Stand- 
ard 
Ari- 
zona. 
Fully 
good 
fair 
Sakel- 
laridis. 
Medi- 
um 
Ari- 
zona. 
Fair 
Sakel- 
laridis. 
3.80 
30's 
60s 
60 2 
100's 
100's 
14.88 
4.29 
11.54 
2.09 
1.77 
15.35 
4.53 
12.02 , 
2.23 
2.02 
15.13 
3.88 
10.85 
2.01 
1.82 
14.99 
4.50 
11.43 
2.14 
1.92 
15.87 j 
4.35 
11.91 j 
2.03 | 
2.00 
14.96 1 15.31 
4.18 4.60 
11.85 12.25 
2.13 2.16 
1.94 1.78 
14.54 
4.10 
12.08 
2.02 
1.92 
14.93 
3.80 
4.25 
3.25 
12.01 
3.80 
1.98 
3.25 
1.69 
6.91 
7.23 j 
6.74 
7.00 
7.23 
7.01 
7.22 
6.93 
6.97 
Table No. VII gives the results obtained from a single thread- 
testing machine. The table is arranged for comparing the different 
yarns with the various kinds of cotton according to grade. The 
results here seem to be somewhat in favor of the Sakellaridis-Egyptian 
cotton, with Sea Island coming second, but where extra choice Sea 
Island is compared with good Sakellaridis, out of five numbers of 
yarn produced, the Sea Island is stronger than the Sakellaridis in 
two cases. 
The single-thread tests 1 were made more for the purpose of ascer- 
taining the relative uniformity in the strength of the different yarns 
than for the average breaking strength. From this point of view 
there was no decided difference between the cottons tested. 
The tensile strength of the yarn was obtained in the laboratory at 
Washington by reeling off skeins of 120 yards each from the various 
grades and kinds of cotton. These skeins were placed on racks in 
order to keep them separate and untangled. A power yarn tester 
was used, the downward stroke of the traverse moving at the rate of 
approximately 12 inches per minute. The humidity was kept as 
nearly constant as possible by taking records with a sling psychrom- 
eter every half hour and regulating the humidifier in the testing 
room. The desired point of relative humidity was 65 per cent. The 
skeins were taken one at a time in rotation from the different racks 
and broken. They were then weighed and the results recorded. 
This operation was repeated, usually 24 times, until the average 
breaking strengths shown in Tables VIII and IX were ascertained. 
From these tables it will be seen that there is no significant relation- 
ship between the breaking strength of the different grades of Ari- 
zona-Egyptian cotton. 2 
1 All single-thread tests were made at the New Bedford Textile School, New Bedford, Mass., by 
William Smith, principal in charge of the carding and spinning department of this school, who also fur- 
nished generous assistance throughout all these tests. 
2 See Bureau of Plant Industry Circular No. 110. 
