BELATION OF CAPACITY TO SLOPE. 



107 



(12) The position of the minimum is related 

 to fineness. For the finer debris it is associated 

 with relatively great width; for the coarser, 

 with smaller width. 



The curves of the fourth group support the 

 ninth inference, that the minimum is most 

 strongly marked for the gentlest slope. 



In the study of the data many other com- 

 parisons of the influence of width were made, 

 but they are not here illustrated. Their chief 

 service was in indicating the comparative value 

 of different divisions of the body of data. The 

 general fact brought out and one emphasized 

 in various other ways is that the measures of 



.093 .183 



.363 



.734 



.545 

 Discharge 



FIGURE 33. Variations of ij in relation to discharge. 



1. 119 



precision derived from discrepancies of observa- 

 tions within a single series by no means cover 

 the whole field. The discrepancies discovered 

 when properties of different series are compared 

 are quite as important and must be given con- 

 sideration in connection with the broader gen- 

 eralizations. 



Let us now consider the relations of the vary- 

 ing value of ij to discharge. These are illus- 



trated by figure 33. The curves of the upper 

 group all pertain to grade (C) and slope 1.0 

 per cent but differ in respect to width of chan- 

 nel. Those of the second group pertain to 

 grade (C) and slope 1.8 per cent; those of the 

 third group to grade (G) and slope 1 .8 per cent. 

 The general fact is that 



(13) As discharge increases the value of i t di- 

 minishes. There are three exceptions, of which 



