CONTENTS. 



FIGURE 17. Diagrammatic longitudinal section of 

 outfall end of trough, illustrating 

 influence of contractor 



18. Profiles of channel bed, illustrating 



fractional rhythms associated with 

 dunes of greater magnitude 



19. Logarithmic graph of C=f(S), for grade 



(G), -=0.66 foot, Q=0.734 ft. 3 /aec... 



20. Extrapolated curves of C=f(S) for vari- 



ous tentative equations of interpola- 

 tion and for slopes greater than 2.1 

 per cent 



21 . Extrapolated curves of C=/(S) for vari- 



ous tentative equations of interpola- 

 tion and for slopes less than 0.8 per 

 cent 



22. The relation of a in C=f(S-a) to the 



curvature of the logarithmic graph. . 



23. Diagrammatic sections of laboratory 



troughs, illustrating relation of cur- 

 rent depth to trough width 



24. Ideal curve of competent slope in rela- 



tion to width of trough 



25. Logarithmic plot of competent slope in 



relation to fineness of debris 



26. Illustration of the method used to ad- 



just values of capacity in relation to 

 slope by means of a logarithmic plot 

 of observed values of capacity in re- 

 lation to slope minus a 



27. Observations of depth of current in re- 



lation to slope 



28. Logarithmic computation sheet, com- 



bining relations of capacity, mean 

 velocity, form ratio, and slope 



29. Logarithmic locus of the exponential 



equation 



30. Locus of log .y=/(log x), illustrating the 



nature of the index of relative varia- 

 tion 



31. Variations of i, in relation to slope 



32. Variations of t, in relation to width of 



channel 



33. Variations of i, in relation to discharge. 



34. Variations of i, in relation to fineness of 



debris 



Variations of exponents i, , j, . and k in 

 relation to slope 



35. 

 36. 



form mode of traction and uniform 

 slope 



37. Curves of C=f(S) for three trough 



widths 



38. Illustration of the relation of capacity 



to width of channel and to form ratio, 

 when slope and discharge are constant 



39. Cross sections of stream channels 



40. Capacity for traction in relation to 



width of channel, when depth and 

 slope are constant 



41. Plot of equation (55) 



42. Logarithmic plots of 



Page. 

 57 



58 

 61 



62 



63 

 65 



67 

 67 

 69 



72 

 87 



95 

 98 



98 

 105 



106 



107 



108 

 113 



116 

 118 



124 

 125 



127 

 129 



130 



Page. 

 FIGURE 43. Relation of capacity, C, to form ratio, 



R. The variation of the function 

 C=b 2 (l+nR)Rm w ith slope 131 



44. Relation of capacity, C, to form ratio, 



R. The variation of the function 

 0=62(1-0-^)^ with discharge 132 



45. Relation of capacity, C, to form ratio, 



R. The variation of the function 

 C=b,(l-aR)Rm w ith fineness of de- 

 bris 133 



46. Relation of capacity, C, to form ratio, 



R. The variation of the function 

 C=b,(l-aR)Rm with slope and dis- 

 charge 134 



47. Logarithmic plots of the relation of 



capacity to discharge 139 



48. Ideal cross section of a stream in the ex- 



periment trough, illustrating the rela- 

 tion of competent discharge to width . 140 



49. Logarithmic plot of K=f(D) 141 



50. Logarithmic plots of capacity for trac- 



tion in relation to fineness of de'bris. . 150 



51. Average departures of original values 



of capacity from system of values 

 readjusted in relation to fineness of 

 debris 152 



52. Vertical velocity curve, drawn to illus- 



trate its theoretic character near the 

 stream's bed 155 



53. Ideal profile 'of a stream bed composed 



of debris grains 155 



54. Ideal curves of velocity in relation to 



depth, illustrating their relation to 



the zone of saltation 161 



55. Tractional capacity for mixed de'bris, 



in relation to proportions of compo- 

 nent grades, with associated curves of 

 fineness and of percentages of voids. . 173 



56. Tractional capacities of components of 



mixed grades in relation to the 

 percentages of the components in the 

 mixtures 174 



57. Curves of capacity in relation to slope 



for grade (A), grade (G), and mixtures 



of those grades 175 



58. Curves of capacity in relation to slope 



for grade (B), grade (F), and mixtures 



of those grades 175 



59. Curves of capacity in relation to slope 



for grade (C), grade (E), and mixtures 



of those grades 176 



60. Curves of capacity in relation to slope 



for a mixture of five grades, (C, D, E, 

 F, G). Comparison of mixture curves 

 for three discharges and of mixture 

 curve with curves for component 

 grades 176 



61. Capacity-slope curves for related mix- 



tures and capacity-discharge curves 



for mixture and component grades. . 177 



62. Capacity-slope curves for a natural 



grade of debris, compared with curves 



for sieve-separated grades 178 



