RUKAL ENGINEERING. 387 



effective, retlucinir the loss over !)0 per cent in some cases. Cement and coal 

 tar are ne.\t in eflicienc.v, while lime and clay pnddle are least effective, the 

 latter reducing seepage about one-half. Hand methods only were cmplo.ved, 

 the lining being mixed thin and spread from a pail handled by one man. Owing 

 partly to the tendency of thin cement mortar to settle and to its great weight, 

 it was found to be much more expensive to ai)i)ly than the^oil, which runs 

 freely at a moderate temperature. Oil and tar were applied to a depth of 

 g'2 in. for each coat, being dusted over with damp earth at once and protected 

 by a backfilling of earth to a depth of 8 to 18 in. Neat cement was ai)plied 

 7;\ to t^ in. thick for each coat, two coats being used. Lime paste was put on 

 in one coat i in. thick. Clay was mixed thin and spread by hand from pans in 

 three layers, giving a total thickness of :} in. 



All the linings were covered with a foot or more of earth which was settled 

 with water, after which the channel was reexcavated to its desired size. It is 

 proposed to continue these experiments for several years, as the most important 

 consideration is the durability of the linings used. 



The exiteriments to determine waste were made on grain fields, experimental 

 plats being selected adjoining fields irrigated in the usual manner. The only 

 difference in the method of application lay in the use of smaller checks on 

 the experimental plats. The excess used by the cultivators was 41 per cent 

 for the first watering, 24 per cent for the second, 20 per cent for the third, and 

 30 per cent for the last. The total depth applied was 0.81 ft. on the plats and 

 l.O.j ft. in the fields. The yield of grain was not materially different on ac- 

 count of the amount of water applied. 



The experiments to determine the number of irrigations for wheat showed 

 that three irrigations would produce a full crop and that more than four were 

 a positive injury. 



An investigation of the natural basis of irrigation farming in North 

 America, A. Golf {Inuug. Diss., Univ. HuUe-^Vittclthcr(J, 1903. pp. SI). — A study 

 of the topography, climate, soil, and water resources of the arid region of the 

 United States in their relation to irrigation. 



Design and construction of small irrigation canals, W. L. Strange (Trans- 

 raal DvpL Irritj. and Water t^iippJij Bid. 2, pp. 7.7, pis. 39). — This is a series 

 of notes dealing with the subject in a, brief but comprehensive way, numerous 

 and valuable practical suggestions being given. In an appendix are included 

 tables of canal discharges based on Bazin's formula and a number of drawings 

 of canal structures in plan, elevation, and section. 



The utility of wind power in agriculture {linpl. and Macli. Rev., 32 (1906), 

 Ao. 317, p. 5JJ). — In commenting upon the uses to which wind power can be 

 put it is suggested that in sawing wood by the aid of a windmill a 24-in. 

 saw blade be used with a 12 to 14 ft. wheel and a 28-in. with a 16-ft. wheel. 

 It is as.serted that a 12-ft. windmill will furnish sufficient power to saw 12 to 15 

 cords per day, and that the same mill in a fair wind will grind 12 to 15 bu. 

 of grain per hour. 



The demand for windmills in British South Africa {Mascli. Ztg., .} (1906), 

 yo. 10, p. 117). — For several years past there has been an agitation in South 

 Africa to undertake the irrigation of extensive tracts of land in that country. 

 Owing to a general business depression these plans have failed of execution, 

 but an impetus has been given to private enterprise by which some excellent 

 results have been obtained. lu this connection there is a constant demand 

 for windmills, most of which are imported from the Uidted State*. 



The mills which have been sent are. according to the writer, far from being 

 modern in design, of faulty construction, and unsuited to the needs of the 



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