ADJUSTMENT OF OBSERVATIONS. 87 



TABLE 12. Adjusted values of capacity, based on data of Table 4, with corresponding values of duty and efficiency Con. 



OBSERVATIONS ON DEPTH. 



MODE OF ADJUSTMENT. 



To adjust the observations of depth it is 

 necessary to deal with their relations to another 

 variable, and either slope or capacity might be 

 used. The selection of the particular variable 

 for comparison was a matter of convenience 

 only, because adjustment to either one would 

 bring the depth values into orderly relation to 

 the adjusted values of the other also; but the 

 question of convenience was not unimportant. 

 A fairly thorough preliminary study was there- 

 fore made, in which the depth measurements 

 for many series were plotted in relation, sever- 

 ally, to measurements of capacity and measure- 

 ments of slope. 



In figure 27 the horizontal scale is that of 

 slope, the vertical of depth. The round dots 

 represent observations made with grade (C), 



width 1.32 feet, and discharge 0.734 ft. 3 /sec. 

 Despite irregularities, the grouping suggests as 



FIGUKE 27. Observations of depth of current, in relation to slope, 

 plotted as dots. The crosses show logarithms of the same depths 

 and slopes. 



the representative lino some such curve as that 

 drawn. On taking account of the physical con- 



