PREFACE vii 



who first applied Mr. Blackman's methods to the study of 

 Growth, first of a fungus under the microscope, and then 

 tentatively to cotton-plants growing in the open field. 



Secondly, a statistical repetition of O'Neill's work 

 on the breaking strain of cotton lint hairs, made by 

 Mr. F. Hughes, Chemist to the Egyptian Ministry of 

 Agriculture, was of very great use. Mr. Hughes ascer- 

 tained the precise significance of such results, and showed 

 from this that an unexpectedly small number of hairs 

 was sufficient to give useful figures. It having thus 

 been shown that single-fibre testing was worth doing, 

 an automatic machine for doing it was the natural out- 

 come, and we now know not only the value of such tests, 

 but also their useless features. 



Thirdly, my own system of routine records of field 

 crop, in the form of Plant-Development Curves, accumu- 

 lated from 1904 to 1914, has provided abundant material 

 from which check data could be drawn as occasion arose. 



The scope of this volume may be criticized as embody- 

 ing much that should properly find its place in scientific 

 journals only. It must not be forgotten, however, that 

 the greater number of its probable readers have not the 

 opportunity to consult reference libraries, although the 

 subject of " Cotton " in all its manifestations is far more 

 of an entity to them than that of botany. That this asso- 

 ciation should have been injurious to research in the past 

 is not a valid reason for withholding information from 

 the growers and users of the future cotton crops. 



W. LAWRENCE BALLS. 



LITTLE SHELFOKD, 



CAMBRIDGE, 



January 1, 1915. 



