580 EXPERIMENT STATION RECORD. [Vol.35 



Irrigation investigations, G. E. P. Smith and A. L. Enger {Arizona 8ta. 

 Rpt. 1915, pp. 570-577, figs. 2). — The work in irrigation investigations at the 

 station for the year is reviewed. Data on tlie economics of pump irrigation in- 

 dicate tliat " in general, the most advisable practice consists in wells of 600 

 to 2,000 gal. capacity, pumps of the sizes from 4 to 8 in., 4-cycle oil engines of 

 from 12 to 60 horsepower, and enough farmers cooperating — two,three, or four — 

 to utilize fully the plant 140 hours each week through the good growing months 

 from April to August." 



Tests of a 15-in., 5-stage, 110-ft. pump with the bottom of the bowls 28.5 ft. 

 below normal water level are also reported. " The tests show that a very 

 high efficiency can be obtained with this type of pump if the pump is working 

 under its best conditions of head and discharge, but that at other heads or other 

 discharges the efficiency may be low. This emphasizes the importance of know- 

 ing the operating conditions in advance and of buying a pump especially de- 

 signed for those conditions." 



The irrigation of sugar cane in Mauritius, F. A. Stockdale {Dept. Agr. 

 Mauritius, Gen. Ser., Bui. 6 {1916), [English Ed.], pp. 12, pi. 1, fig. i).— This 

 pamphlet deals with the scientific principles and the essentials of practice of 

 irrigation with special reference to the irrigation of sugar cane on the island. 



The operations of the Boyal Commission of Irrigation in the first trien- 

 nium, O. Bordiga {Atti R. 1st. Incoragg. Napoli, 6. ser., 66 {1915), pp. 1-16). — 

 The first three years' activities of the commission are reported, which deal 

 briefly with defects in the irrigation laws of Italy ; irrigability of lands ; irri- 

 gation economics ; and irrigation water, its quality and action on crops and soil. 



Annual irrigation revenue report of the Government of Bengal for the 

 year 1914-15 {Ann. Irrig. Rev. Rpt. Bengal, 191^-15, pp. 11+71, pi. i).— This 

 report covers the year 1914-15. 



Report of the state drainage commission of Minnesota {Rpt. State Drain. 

 Com. Minn., 1915, pp. 68, j:>ls. 11). — This reports the activities of the state 

 drainage commission of Minnesota and the work and expenditures of the state 

 drainage engineer's office. The text of the laws prescribing the duties and 

 defining the powers of the state drainage commission is also given, together 

 with engineering information regarding drainage areas in Minnesota, evapora- 

 tion, precipitation, run-ofC waters and formulas, state ditches, and maximum, 

 minimum, and average discharge of various streams of the State. 



Tests show strength of corrugated culvert pipe, G. L. Fowler {Engin. Rec, 

 75 {1916), No. 21, pp. 668, 669, figs. 4; abs. in Engin. News, 75 {1916), No. 20, 

 p. 958). — Tests under hydrostatic pressure of 12-, 24-, and 4S-in. corrugated iron 

 pipes with corrugation depths of J and i in. and uniform pitch of corrugations 

 of 2§ in., and sand bed tests of the same, are reported. Considering the three 

 variables, diameter of pipe, thickness of metal, and depth of corrugation, the 

 following formula was developed : 



, 5,960Cr / „ ,, D\ 



where P=collapsing pressure in pounds per square inch, C=corrngation depth 



in inches, !r=thickness of metal in inches, and /)=inside diameter in inches. 



For sizes from 10 to 24 in., metal thicknesses of from 0.0025 to 0.141 in., and 



working pressure of half the collapsing strength, the formula was simplified to 



34 00007" 

 working pressure== —^-jy — • on the assumption that for this range of sizes the 



collapsing pressure varies inversely as the diameter. 



