SPINNING TESTS OF UPLAND LONG-STAPLE COTTONS. 15 



bale in favor of the Carolina staple cottons as against the Delta, while 

 on the 23 to 25 per cent setting the average of the Carolina cotton 

 shown in the last column in Table IX is $6.95, and that of the Delta 

 $7.85, a difference of 90 cents per bale, in favor of the Delta on the 

 wider setting. 



The grade of the samples being tested does not appreciably affect 

 the quantity of the comber waste, as is shown by comparing Durangu 

 and Lewis, both of which are good middling, but which show a dif- 

 ference of 8.28 per cent in comber waste on the 23 to 25 per cent 

 setting. 



ACCURACY OF THE MACHINE WORK. 



The following mathematical formulae show that the variations in 

 percentages between the 13 to 15 per cent and 23 to 25 per cent set- 

 tings on the bales showing highest and lowest waste are consistent 

 with the mechanical changes involved : 

 25-^-15=1.66, the ratio between the two settings. 

 21.81-^-13.07=1.668, the ratio between the two percentages actually 



obtained on the Webber No. 1. 

 12.15-f-8.08 = 1.504, the ratio between the two percentages actually 

 obtained on the Lewis cotton. 



The mechanical construction of the comber is such that all fibers 

 up to any desired length are taken out, so that these results repre- 

 sent fairly the inherent value of each bale tested, when used 

 for fabrics which require combed yarns. If later tests substantiate 

 the findings of this report, namely, that these bales are representative* 

 of inherent differences in the varieties represented, as there is every 

 reason to assume, the great importance to the spinner of knowledge 

 concerning the varieties of cotton purchased for his mills will be 

 fully demonstrated. It is not safe to assume, however, that the same 

 differences will be found between representative bales of these vari- 

 eties when the latter are grown under radically different climatic 

 conditions. In other words, uniformity may prove to be a much 

 more constant characteristic of some varieties than of others. 



FACTORS INFLUENCING WASTE. 



There are a multitude of factors which influence the percentage of 

 waste in such tests as those here discussed. If cotton is picked and 

 ginned while damp, or is ginned at too high speed, even the best 

 varieties may be so damaged as to show large percentages of card 

 and comber waste. The mixing of long and short staple seed, at the 

 gin or otherwise, results in the production of cotton lacking uni- 

 formity or " body." 



