ENVIRONMENT OF THE BOLL 107 



Consequently, the breaking strain of a fibre is very 

 largely determined, if not entirely, by its weight, or, in 

 other words, by the thickness of its cell wall. This 

 holds good between very different types of Egyptian 

 cotton, and is independent of the lint length or of the 

 site in which the cotton is grown. The sample marked 

 310 N. was grown at Neguileh, in the Northern Delta, over 

 a hundred miles away from Giza, where the others were 

 grown. The two sample" marked with a star (77 G. and 

 310 N.) were respectively of Nubari and Sea Island type, 

 and were both graded as extremely strong, or SSSS on the 

 grader's scale, but 310 N. was much " finer " than 77 G. 



This last result carries us on to the gradings of the 



dated flowers, but before leaving the subject of weight 



Number of ^ sm ^ e nn ^ nau?s ^ may be interesting to 



Hairs per note that the mean lint length of 310 N., 

 Seed. taken hair by hair, is just over 41 milli- 

 metres, and that the weight of lint on a single seed is 

 about 0-033 gramme; since 10 millimetres of a single lint 

 hair in its thickest part weighs 0-00122 milligramme, one 

 hair will weigh about 0-00400 milligramme, and there must 

 consequently be about 8,000 hairs on a single seed, whose 

 aggregate length at 41 millimetres per hair must be 

 328,000 millimetres, or 328 metres. 



The hairs from five seeds only of 310 N. would there- 

 fore extend for a mile if placed end to end. 



It is rather interesting to notice also that the sample 

 77 G. also works out at about 8,000 hairs per seed; for 

 though each hair weighs more, the lint weight per seed 

 happens to be greater. 



