258 



TRANSPORTATION OF DEBRIS BY RUNNING WATER. 



edge. The brass guides and the adjacent parts 

 of the wooden shaft wall were shaped to a 45 

 bevel, which, if produced, would reach the edge 

 of the opening in the fixed plate. 



Movements of the slide were controlled from 

 the outside. A brass rod, 0, firmly attached 

 to it and running parallel to its axis (fig. 89J), 

 rested in a frame at the left of the opening 

 (fig. 89, e), where its motion was controlled by 

 rack and pinion, the rack being cut on the 

 upper side of the rod. At the left of the frame 

 and pinion the rod slid along a brass scale 

 graduated to inches and tenths; and the gate 

 was set for any desired width of aperture by 

 bringing an engraved index mark on the rod 

 opposite the proper mark on the scale. 



The operation of the gate was found to be 

 satisfactory. 



The head under which the jet issued, meas- 

 ured from the middle of the opening to the 

 water surface in the upper tank, was 6.0 feet, 

 plus or minus a small fraction observed by 

 means of the gage above mentioned. 



PLAN OF EATING. 



The method of rating was volumetric and 

 empiric. The gate having been set at a par- 

 ticular graduation, and the discharge having 

 been, continued until the rate of flow through 

 the stilling tank and experiment trough had 

 become steady, the outflow of the trough was 

 diverted for a measured time into a special 



ZS/////////X 



Section through C-D 

 5 10 



Section through E-f 

 15 20 ZS Inches 



FIGURE 89. Elevation and sections of gate for the measurement of discharge. 



reservoir where its volume was measured. The 

 special reservoir is shown in figure 88 as " sump 

 No. 2," and the diverting apparatus also is 

 indicated. The "diverting trough" was piv- 

 oted at the remote end and could be turned 

 quickly by hand. In one position it received 

 the discharge from the experiment trough and 

 delivered it to sump No. 1, containing the 

 supply for the pump; in another it permitted 

 the water to fall into sump No. 2, arranged for 

 measurement. The work of rating was per- 

 formed by J. A. Burgess, and a full report upon 

 it constituted his graduation thesis in engi- 

 neering at the University of California. The 

 details of apparatus and method were arranged 



by him, and the following account of the rating 

 is essentially an abridgment of his report. 



CALIBRATION OF THE MEASURING RESERVOIR. 



Sump No. 2, constructed of concrete, was 

 approximately rectangular but was not quite 

 regular in form. No attempt was made to 

 base computations of volume on its linear 

 dimensions, but a scale of volumes was gradu- 

 ated directly. A hook gage was first installed, 

 the hook being attached to a vertical rod, to 

 which slow motion could be given. An index 

 borne by the rod near its upper end followed a 

 smooth surface which had been prepared to 

 receive a graduation but initially was un- 



