CONTENTS. 



r> v, 



Preface 



Abstract 



Notation 



CHAPTER I. The observations 



Introduction 



General classification 



Stream traction 



Outline of course of experimentation 



Scope of experiments 



Accessory studies 



Flume traction 



Apparatus and material 



Experiment troughs 



Water supply 



The water circuit 



Discharge 



Sand feed 



Sand arrester 



Settling tank 



Gage for depth measurement 



Level for slope measurement 



Pitot-Darcy gage 



Sand and gravel 



Methods of experimentation 



General procedure for a single experiment. 



Details of procedure 



Width of channel 



Discharge 



The feeding of sand 



The collection of sand 



Determination of load 



Determination of slope 



Contractor 



Measurement of depth 



Measurement of velocity 



Modes of transportation 



Movement of individual particles 



Rolling . 



Saltation 



Collective movement 



Units 



Terms 



Load 



Capacity .* 



Competence 



Discharge 



Slope 



Size of debris 



Form ratio 



Duty and efficiency 



Symbols 



Table of observations on stream traction. . 



Tage. 



9 CHAPTER II. Adjustment of observations 55 



10 Observations on capacity and slope 55 



13 The observational series 55 



15 Errors 56 



15 Intake influences 56 



15 Outfall influences 56 



15 Changes in apparatus 57 



17 Rhythm 58 



17 Slopes of debris and water surface 59 



18 The logarithmic plots 59 



18 Selection of an interpolation formula 60 



19 The constant a and competent slope 65 



19 Interpolation 72 



'19 Precision 73 



19 Duty 74 



20 Efficiency 75 



20 Observations on depth 87 



20 Mode of adjustment 87 



21 Precision 94 



21 Mean velocity 94 



21 Form ratio 94 



21 Graphic computation 94 



21 CHAPTER III. Relation of capacity to slope 96 



22 Introduction 96 



22 In channels of fixed width 96 



22 The conditions 96 



22 The sigma formula 96 



22 The power function and the index of rela- 



23 tive variation 97 



24 The synthetic index 99 



24 Application to the sigma function 99 



25 Variation of the index 104 



25 Formulation with constant coefficient 109 



25 Effect of changing the unit of slope 112 



26 Precision 113 



26 Evidence from experiments with mixed 



26 debris 113 



26 Relation of index to mode of traction 115 



26 In channels of similar section 116 



30 The conditions 116 



34 Sigma and the index 117 



35 The synthetic index 119 



35 Summary 120 



35 Review 120 



35 Duty and efficiency 121 



35 CHAPTER IV. Relation of capacity to form ratio 124 



35 Introduction 124 



35 Selection of a formula 124 



35 Maximum 124 



36 Capacity and width 125 



36 Capacity and depth -. . 127 



36 Capacity and form ratio 128 



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