354 Annual Report Agricultural Experiment Station 



A few years ago pump irrigators had available an engine fuel 

 oil of suitable quality, but of low cost. This oil has been called by 

 various names, including tops and gas oil. Gas oils with a flash 

 point of about 100° F. and with a gravity of about 44° B. were to 

 be bought at five to six cents a gallon. Recently, while the price 

 has been going up the quality has been going down. The tops now 

 being furnished by many refineries is of about 37° gravity and is 

 very troublesome in engines of the ordinary type and size. Mean- 

 while engine distillate has depreciated in quality until it is no better 

 for irrigation pumping than was the gas oil of five years ago, altho 

 the price is three times as great. The increase in cost is due in part 

 to the fact that the engine distillate is classified as a finished product 

 and therefore takes the same freight rate as gasoline. The Fuel 

 Administration offers no relief. A few of the smaller oil companies 

 continue to furnish a satisfactory tops at a reasonable price. Pump 

 irrigators should demand an unrefined distillate of 40° to 44° gravity 

 and with flash point under 120° F. This oil takes a low freight 

 rate, and moreover the cost of refining will be saved. Unless some 

 relief is obtained in this matter, pump irrigation will be more re- 

 stricted and less profitable than has been thought hitherto. 



CEMENT PIPE FOR IRRIGATION PIPE LINES 



CEMENT pipe; failures 



Several important studies of cement irrigation pipe have been 

 made during the past year. 



The study of failures of cement pipe was necessitated by failure 



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SEiTlvetrf FORMS TfOT 



CB.ACK£D 



fV£.3T ^IDB 30UTH ^JDB BAST ^IDB NOB.TH ^IDB 



Fig. 6 — A cracked gate pit at Continental, caused l.y exiiansion of i>ii)e line. 



of a long line of 20-inch pipe at Continental, Arizona. Sections of 

 this line, from 20 to 1000 feet at a time, failed by longitudinal cracks. 

 An example of a break is shown in Fig. 5. The photograph was 



