gg2 EXPERIMENT STATION RECORD. 



lowing general topics are discussed: Farm buildings and building materials, 

 farm water supply and sewage disposal, farm power, drainage and irrigation, 

 the cost of road building, the working principles of orchard heaters, and the 

 forms of electricity. A final section gives useful tables for engineering 

 calculations. 



Irrigation laws of the State of New Mexico {Santa Fe, N. Mex.: State Bd. 

 Water Comrs., 19U, pp. 67).— The text of the laws is given. 



The Colorado statute inch and some miner's inch measuring devices, V. M. 

 Co^E (Colorado Sta. Bui. 207 {1915), pp. 3-16, figs. 5).— This bulletin, based 

 on a cooperative agreement between the Office of Experiment Stations and the 

 Colorado Station, reports the results of a series of experiments on box tubes, 

 thin-edged orifices with free flow, and the so-called Uncompahgre orifice, the 

 object of which was to secure definite information concerning the Colorado 

 statute inch and experiments on the so-called Azusa hydrant, a miner's inch 

 device used in southern California (E. S. R., 32, p. 683). 



In the box-tube experiments the boxes used were 16 ft. long and were given 

 a descending grade of i in. to the foot, the discharge end being, therefore, 2 in. 

 lower than the intake end. Metal strips J in. thick were placed around the 

 intake end of each box so the inside dimensions of the orifice could be accu- 

 rately determined. The inside depth of the box was practically 6 in. in every 

 case and the water surface was 5 in. above the top of the orifice. A thin metal 

 slide was made to fit between the metal strips on the end of the box, and 

 this was adjusted to give any width of opening from 2 to 16 in. It was found 

 in general that the discharge for any certain size of orifice increased as the 

 width of the boxes increased, except for a slight reduction when the orifice 

 was nearly the same size as the box. " The number of statute inches to one 

 second- foot, therefore, decreases with a decrease in the size of the box, and 

 also the number of statute inches to one second-foot increases as the size of 

 the orifice is increased, which means that the discharge of each square inch 

 of orifice decreases as the size of the orifice is increased. This is the opposite 

 to the results obtained with thin-edged orifices having free flow. Box tubes with 

 orifices from 12 to 96 sq. in. gave discharges with the number of statute inches 

 to 1 second-foot varying from 33.7 to 38.4, and a greater number would no 

 doubt be obtained for still larger orifices." 



In the experiments with thin-edged orifices with free-flow sizes of orifice rang- 

 ing from 1 in. square to 6 in. deep by 6 in. wide were used. The depth of water 

 above the top of the orifice was 5 in. in every case. A concrete box was used 

 having a cross section of 10 ft. by 6 ft. It was found that the discharge for 

 each square inch of opening increased as the size of the opening was increased. 

 " For a constant depth of orifice the discharge per square inch of opening is the 

 greatest for a width of 1 in., decreases as the width is increased for a few 

 inches, or approximately until the orifice is square for the larger sizes of 

 orifices, and then increases as the width is increased. The number of statute 

 inches to 1 second-foot varies from 42.9 to 35.5, but for the sizes of orifices com- 

 monly used for measuring water to the individual irrigator it is probable the 

 value would be from 36 to 37, and as low as 35 might be obtained for wider 

 orifices. . . . The discharge through full contraction, thin-edged, free-flow 

 orifices having a depth or vertical dimension of 6 in. and a head of 5 in. above 

 the top of the orifice, is represented by the formula 



Q-0.1696-0.0e+j^»lp-. 



in which Q is in second-feet and b is the breadth or horizontal dimension of the 

 orifice in inches." 



