286 EXPERIMENT STATION RECORD. [Vol. 37 



" Willows are cut by men with grubbing hoes and brush scythes. Men 

 equipped with grubbing hoes go ahead for cutting out larger willows, and men 

 with scythes follow and cut the remainder." 



Drainage {Minnesota Sta., Rpt. Crookston Substa., 1910-1916, pp. 20-27, 

 figs. S). — This is a brief report on a seven years' test of a tile drainage system 

 at the Northwest Substation at Crookston, Minn. The soil is a dark, sticky 

 clay loam with a heavy compact bluish gray clay subsoil. 



" Tile drainage is limited in operation to the period after the frost is out 

 above them. This makes shallow surface ditches necessary for early spring 

 drainage. Cib.>^ervations have emphasized the necessity of supplementing tile 

 drains with surface ditches during the entire growing season in order to secure 

 the best results. . . . The drainage system has been fimnd to be of the greatest 

 service. The two detailed inspections whicli have been made, in 1912 and 

 1916. showed the tile in as good r ndition as in other localities." 



By-products of land clearing (ilinnesoia Stn., Rpt. Dtiluth Substa., 1916, 

 pp. 9, 10). — The receipts per acre for lumber, cordwood, and fence posts were 

 found to be .$G2.08, with a total cost for clearing up to the stumping stage of 

 $57.39 per acre. 



The soil saving dam. W. H. Baker {J'niv. .Mitfioiin Agr. Ext. Scrv. Circ. 14 

 (1917), pp. -}• ^g^- ^^■' — This circular descrihos and illu'=;trates the construction 

 of dams the purpose of which is to hasten the filling up of washed ditches on 

 farms by preventing the sudden rnn-off of storm water. 



A comparative bacteriological study of the water supply of the city and 

 county of Denver. Colo., W. G. Sackett (Colorado Sta. Bttl. 225 (1917), pp. 

 S-lJf, pis. 4, figs. 2). — This bulletin describes the water supply system of the 

 city and county of Denver, Colo., and the methods of purification in use and 

 reports comparative bacteriological tests of samples of the purified water 

 made by four different experimenters, of which the author reported for the 

 Colorado Station. 



In these tests the results from the four sources were very uniform. Attention 

 Is called "to the excellent and safe condition of the filtered and treated waters^ 

 as shown by the low gelatin and agar counts and by the total absence of 

 Bacillus coli from the main supply, compT>ing ;n all respects with the standard] 

 adopted by the Public Health Service of the U. S. Treasury Department." 



Data on the prevalence of typhoid in the city and county of Denver and thej 

 text of the ordinance protecting the watershed arc also given. 



The activated sludge process of sewage purification, E. Akdekn (JourJ 

 Soc. Chem. Indus., SB (I'Jll). No. 2, pp. 65-68; Surveyor, 51 (1917), Xo. ISHA 

 pp. 298-300). — Further studies on the activated sludge process (E. S. R., 34,j 

 p. 888), including experiments on the effect of trade effluents on the process, 

 reported. 



It was found " that, contrary to the opinion formed as the result of earlier| 

 experiments when working with a strong trade sewage, the maintenance ol 

 the activity of the sludge is not dependent on the stage to which nitrificatioi 

 is carried. When dealing with a sewage free from inhibitory trade effluent 

 no appreciable loss of eflicicncy need be anticipated in this country [England] 

 during the winter months. While the problem of disposal of the sludge remair 

 to be fully developed, it would certainly appear from kno^^^l data that tht 

 cost of dewatering and drying will be more than repaid by the value of the 

 resultant dried sludge." 



Sewage disposal for village and niral homes. C. S. Nichols (loira Engit 

 E.rpt. Sta. Dill. 1,1 (1916). pp. 29. figs. 10. pis. 5).— It is the pun>osc of this bul- 

 letin to correct dangerous misconceptions recently published about septic tanks,| 

 to point out the general principles covering the proper disposal of househok 



