1032 EXPERIMENT STATION RECORD. 



use to both the general and the engineering public, all the available hydrographic 

 information in regard to this important area." 



Irrigation in the Karroo, P. J. Du Toit (Agr. Jour. Cape Good Hope, 26 (J 905), 

 No. 1, pp. 62-68). — Descriptions are given of successful and unsuccessful schemes, 

 especially those along the Visch, Zak, and Orange rivers. The unsuccessful schemes 

 include those in which flood water is conserved in a large dam and led on to land 

 below the wall; the successful schemes include those in which flood waters are 

 impeded jn their course and spread over. the land above the wall, and those in which 

 irrigation is done by diversion from perennial streams. The first are largely gov- 

 ernment enterprises; the second mainly private; the third both public and private. 



The utilization of Karroo flood waters ( Agr. Jam-. Cape Good Hope, 96 (1905), 

 No. 1, pp. 88-100, ph. 2, fig*. 7). — The work and methods used on a large farm near 

 Schoombie to divert and spread flood waters over the land are described and the 

 results of the practice are discussed. 



Land treatment of sewage: I. General report, G. McGowan, A. C. Houston, 

 and G. B. Kershaw. II. Chemical report, G. McGowan. III. Bacteriological 

 report, A. C. Houston. IV. Engineering and practical report, G. B. Kershaw 

 (Roy. Com. Sewage Disposal [Great Britain] RpL, 4 (1904), pis. 1, pp. 116, dgms. 18; 

 2, pp. IV+328, dgms. 40; 3, j>j>. 214, pis. 4, dgms. IS; 4, pp. 129, dgms. 53).— This 

 report gives the results of a general inspection and detailed observations on 8 repre- 

 sentative sewage farms by the Royal Commission on Sewage Disposal. The 8 farms 

 were classified and studied according to the type of soil employed, 7 fairly represent- 

 ative soils being included as follows: Sand, sand and gravel, light loam, heavy loam, 

 clay, peat, and chalk. The data recorded relate to situation, size, and irrigated area 

 of the farms; the population supplying the sewage; amount, dry-weather flow, char- 

 acter, and method of treatment of the sewage; character of soil and subsoil; length 

 of time the farm has been in operation; the method of handling the sewage and dis- 

 posing of the effluents; chemical and bacteriological examinations of the sewage and 

 effluents; mechanical analyses of the soils and subsoils of the farms, etc. 



The report also reviews previous work of the Rivers Pollution Commission in its 

 bearing upon this subject. Data are given in detail in numerous tables and are 

 shown graphically in colored diagrams. 



The more important points brought out in the report are summarized as follows: 



"In the first place, the best kind of soil for filtration purposes (e. g., light sandy 

 loam overlying gravel and sand) can certainly purify to a remarkable extent, at the 

 rate of 23,000 gals, of a strong mixed sewage per acre per 24 hours (a) at a given 

 time; and over 10,000 gals, per acre per 24 hours (b) on the year's working of the 

 total irrigable area. Further, under (a) and (b) sets of conditions, over 100,000 and 

 over 30,000 gals., respectively, of a rather weak sewage can be purified to a fair 

 although not to an altogether satisfactory extent. 



"Secondly, with soil less well suited for filtration purposes (e. g., sand and par- 

 tially peaty soil lying upon sand and gravel), from about 25,000 to 46,000 gals, of 

 sewage per acre per 24 hours (a) at a given time; and from about 8,000 to 23,000 

 gals, per acre per 24 hours (b) on the year's working of the total irrigable area, 

 can be treated so as to yield effluents fairly good, but, on the whole, not quite 

 satisfactory. 



"Thirdly, with soils passing from gravelly loam to heavy loam or clay, all being 

 worked as combined surface irrigation and filtration farms, from about 12,000 to 

 57,000 gals, of sewage per acre per 24 hours (a) at a given time; and from about 

 4,000 to 9,000 gals, per acre per 24 hours (b) on the year's working of the total irri- 

 gable area can be treated so as to yield effluents moderately good, but still not alto- 

 gether satisfactory. 



" To summarize all the results within the limits of a few sentences is impossible, 

 bul we may say in conclusion, and speaking in general terms, that wedoubt whether 

 even the most suitable kind of soil worked as a filtration farm should be called upon 



