114 



TRANSPORTATION OF DEBBIS BY RUNNING WATER. 



appeared to be zero. For another it fell between 

 the values which had been assigned to the finer 

 and coarser components of the mixture. For 

 the remaining third it exceeded the values asso- 

 ciated with the components. When the load 

 was a mixture of many grades combined in ap- 

 proximately natural proportions, and also when 

 it consisted of unsorted debris from a river bed, 



the values of a were small and for the most part 

 zero. 



These features were scrutinized with special 

 interest because the properties of grade (E) 

 had suggested that great range of fineness 

 might determine very low values of a. On the 

 whole, the data from mixtures favor that view, 

 but their support is by no means unanimous. 



TABLE 17. Values o/i,/or mixtures of two or more grades of debris. 



