REPORT BY DR. W. LAWRENCE BALLS 161 



cross section, and hence, other things being equal, tlie finer the count 

 which can be spun witliout reducing the number of hairs in cross 

 section too low. 



(E) SORTING 



All the samples were put through the Sledge Sorter,* an illustration 

 of which will be found in the advertisement pages of this volume, 

 and the curves shown express the percentage distribution by weight 

 for the various lengths of staple found in each sample. Duplicate 

 tests were made on each sample, so that in this way some idea of 

 the error of the test can be gathered. 



It may he noted that the Ceara samples were difficult both to 

 draft and sorb owing to their extreme fineness. 



It will be noticed that all the curves show an apparent tail of 

 long hairs, but this — as explained in the handbook of the Sorter* — is 

 fictitious ; and to obtain a true idea of the composition of the samples, 

 the rapidly falling front portion of the curve should be projected 

 downwards to cut the base line. 



GENERAL COMMENTS ON OBSERVATIONS 



It will be seen that the Ceara samples (from the Jaguaribe valley) 

 are extremely fine, whether judged by hair weight, or even more so 

 by ribbon width. Their hair break is, at first sight, rather low, but 

 upon correcting for fineness, they are seen (in the " Relative Hair 

 Break "' column) to l)e greatly superior to the samples of Moco and 

 Verdao. 



At the same time, this superiority is not abnormal. On comparing 

 the Ceara with Sakel and No. 77 in this respect, they will be seen to 

 be about equal thereto, whereas the Moco and Verdao samples are 

 not only inferior to Egyjjtian in this essential characteristic but also 

 to the American. Although this fact appears unfavourable to the 

 Moco samples, it should be carefully observed that we are comparing 

 country cotton from Brazil with crop cotton from experimental plots 

 in America, and it is probable that better cultivation would lessen 

 the difference. 



This '■ Relative Hair Break "' comparison is really the essential 

 thing, and the other features of the tests are of comparatively minor 

 interest ; but it must be carefully observed that while " Relative 

 Hair Break " shows the intrinsic strength of the yarn which the cotton 

 may be expected to produce, it does not indicate whether the cotton 

 will draft smoothly or not ; and it is quite possible for a cotton which 

 is intrinsically strong to behave so badly in drafting as to produce 

 weak yarn. For this we have, as yet, no direct test, except the test 

 of actual spinning ;| and it should be noted that, as mentioned above, 

 the Ceara samples were decidedly difficult to draft in preparation for 

 sorting. In this respect, however, they merely resemble other very 

 fine cottons. 



* " A Method for Measuring the Length of Cotton Hairs " by W. Lawrence Balls 

 (MacMillan & Co., London, 1921). 



t " A Handbook of Spinning Tests for Cotton Growers " by W. Lawrence Balls 

 (MacMillan & Co., London, 1920). 



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