RURAL ENGINEERING. 385 



Seepage measurements were made ou the main canal and several of the 

 laterals, the results in average percentage of loss per mile being as follows : 

 Main canal. 1.17 per cent; low line, 1.95 per cent; high line, 1.41 per cent; 

 main laterals, 3.29 per cent ; coolies, 0.9 per cent. The natural channels therefore 

 show the smallest loss, and the percentage of loss in the artificial channels 

 increases as the volume of water decreases. 



Weir experiments, coefficients, and formulas, R. E. Morton ( U. S. Geol. 

 Siirrci/. Wdtcr-SiiitpUj aud Irruj. Paper Xo. 2(iO. pp. 193, pis. 38, figs. 17). — This 

 is a revision of Paper No. 150 of the same series, the change consisting in the 

 addition of tables giving the discharge over thin-edge weirs by Bazin's formula, 

 and tables giving multipliers for the determination of the discharge over broad- 

 crested weirs, all prepared by E. C. Murphy. 



Report on the drainage of the eastern parts of Cass, Traill, Grand Forks, 

 Walsh, and Pembina counties. North Dakota, J. T. Stewart ( f '. *S'. Dcpt. Agr., 

 Office Expi. Stas. Bid. ISO, pp. 77, pis. 6. figs. 2). — The surveys reported in this 

 bulletin dealt with lands which represent an area of about 3.0()(),0(M) acres in 

 the valley of the Red River of the North, which has so little fall that in many 

 years the soil is too wet for crop production. 



The surveys were made for the purpose of determining the feasibility of 

 draining the valley, the location and size of drains necessary, and the cost of 

 their construction. The work was done by this Office in cooperation with the 

 State of North Dakota, the counties in which the surveys were made, and the 

 Great Northern Railway Company. 



The report deals with the general topographical and climatic conditions and 

 characteristics of streams tributary to Red River, the size, form, and silting of 

 ditches, the erosion of channels, the effect of straightening natural drainage 

 channels, and estimates and recommendations in general and in detail for each 

 separate county represented. It is shown that faulty drainage can, in great 

 measure, be overcome by increasing the efficiency of existing natural water 

 courses, by sti*aightening the channels, removing obstructions, and building 

 levees at low points. 



" Where banks of streams are higher than the land a short distance away 

 from them, as is true of nearly all of the streams in the valley, they act as 

 natural levees to hold the streams within their channels and should not be cut 

 to furnish an outlet for a drainage ditch unless it is impossible to secure such 

 outlet in any other way. There are usually coulees and natural channels 

 running parallel to the streams, back of the bank ridge, which finally enter the 

 main stream, into which ditches may be discharged. Wherever it is possible all 

 ditches should enter the streams through these natural channels. It would 

 greatly facilitate drainage movements in the area surveyed if tributary streams 

 were declared drainage channels and placed under the supervision of drainage 

 authorities." 



Examination and classification of rocks for road building, including the 

 physical properties of rocks with reference to their mineral composition 

 and structure, E. C. E. Lord {I. H. Dcpt. Agr., Office Pub. Roads Bui. 31. pp. 

 2!), pis. 10, fig. 1). — This bulletin describes in some detail the more important 

 quantitative methods of microscopic rock analysis used in the Office of Public 

 Roads, and reports the results of such examinations, proposes a classification 

 of road material suited to the requirements of road builders and engineers, and 

 discusses the relation of the physical properties of rocks to their mineral com- 

 l)osition and structure. 



The road-making rocks examined are graded into classes, types, families, 

 and subfamilies or varieties, and the various distinguishing features of each 

 group explained at length. 



