RURAL ENGINEERING. 885 



RURAL ENGINEERING. 



Cost of pumping from wells for the irrigation of rice in Louisiana and 

 Arkansas, W. B. (Jrixoky (U. S. Dritt. A(jr., Office E.ipt. filafi. Bid. 201, pp. 

 39, fifl!^. 2). — 111 continuation of work pi-eviously noted (E. S. 11., 19, p. 86), this 

 l)iilletiu gives the i-esults of tests made to determine the relative cost as well 

 MS the efficiency of the methods and machinery used for irrigation pumping in 

 Ivoui^iana and Arkansas, with a view to supplying data to enable rice growers 

 to decide whether to purchase water or to install individual plants. 



The 18 plants tested are described in detail, with the results of each tabu- 

 l:ited and peculiarities in conditions noted. The author notes that in cer- 

 tain plants liMving submerged centrifugal pumps the efficiency of engines, pumps, 

 and wells could not be segregated because of the lack of a vacuum gauge 

 attached to the suction i)ipe, and where there was a poor showing made the fault 

 could not be assigned. 



As a result of the tests the writer says, " it appears that under ordinary 

 conditions there is a slight financial advantage in securing water from a canal." 



Pumping for irrigation, E. Rabete (Jour. .\f/r. Prat., n. scr., 16 {1908), No. 

 Jil, pp. 6'-7-}-0".3N ) . — Two conventions were held rec-ently at Cahors and Villeneuve- 

 sur-Lot, to investigate the economic \filue and make tests of the various methods 

 of pumping water in large quantities for irrigation. The conclusions from the 

 convention at Cahors are briefly summarized in the article, among them being 

 that machines furnishing the largest output show the least cost of I'enewal, and 

 that, other conditions being equal, slow-speed motors are the most economical. 

 The results of the Villeneuve convention are given fully. 



At Villeneuve there were in all 16 pumping units tested. Of these 12 had 

 motors of the explosive type and were operated in these tests on naphtha of 

 specific gravity 0.7, 3 had electric motors operated by a continuous current of 

 230 volts, and 1 had a hot-air engine. In tables showing the experimental 

 and calculated results three classes are observed: (1) Pumping units with an 

 hourly output of more than 36 cu. meters of water lifted to a height of 5 

 meters; (2) between 5 and 36 cu. meters; and (3) less than 5 cu. meters of 

 water. Many combinations of motors and pumps were tested, as, for example, 

 in the first class were found stationary and movable motors with centrifugal 

 pumps and electric motors belt-connected to centrifugal pumps. In the second 

 class there were centrifugal, duplex, and triplex pumps with belt connections 

 and also a diaphragm pump, all of which were operated by explosive motors. 

 In the third class there were electric motors direct-connected and geared to 

 centrifugal pumps, and also a hot-air engine operating a piston pump. 



A table gives the results of cost and output by the hour, and by 100 kg. 

 raised 5 meters. The costs in each class per horsepower per hour were approxi- 

 mately 0, 22, and 26 cts., respectively, with naphtha at 30 cts. per gallon and 

 electric current at 5 cts. per kilowatt-hour. 



The high economy of units of large outimt, the advantages of electric motors 

 of small and average output, and the practical merits of hot-air engines are 

 noted as conclusions from the tests. 



Irrigation pumping, A. Chatterton {lipt. Drpf. A (jr. Mndrasi, JPOli-S, pp. 

 2.'>-.il). — This report contains infornuition on the installation of oil engines in 

 that locality, the experiments made on government plants to determine the duty 

 and a basis for the sale of water, and the governmental assistance rendered to 

 irrigators in installing pumps. In a few cases the water is taken from streams, 

 but mostly from driven wells. There is also a general account of well-boring 

 operations as carried on in this district. 



