714 EXPERIMENT STATION RECORD. 



Water supply and sewerage {Ann. R/jt. Bd. Health .l/fl.s,s., SS (1906), pp. 

 69-349, j)ls. 10). — Xlie subjects discussed in this report are as usual advice 

 given to cities, towns, public institutions, and individuals regarding water and 

 ice supply, examination of public water supplies and rivers, water-supply statis- 

 tics, and experiments on the purification of sewage and water at the I^awrence 

 Experiment Station in 190G, including purification of sewage, water filtration, 

 and the significance of the numbers of bacteria in water and sewage developing 

 at different temperatures (E. S. R., 18, p. 212). 



Contribution on the role of the septic tank in the biological purification of 

 sewage, S. K. Dzerszgowski {Arch. Sci. Biol. [St. Pctersl).], 13 {1907), No. 1, 

 pp. 25-68, figa. 3). — From a somewhat detailed study of this subject at the sew- 

 age purification station at Tsarskoye-Selo near St. Petersburg, the author con- 

 cludes that the principal function of the septic tank is to remove the suspended 

 organic and mineral matter, or that, in other words, the septic tank acts pri- 

 marily as a sedimentation basin. While the biological processes bring about 

 changes which reduce the volume of this sediment and facilitate the processes 

 of purification, the rate of disintegration and solution is so slow that only a 

 small fraction of the daily product is so destroyed. As an independent agent 

 of purification the septic tank is considered of little value, a positive disad- 

 Aantage as a preparation of sewage for further treatment on contact beds and 

 filters, and useless for lai'ge purification plants provided with mechanical ap- 

 paratus for removing suspended matter. 



SOILS— FERTILIZERS. 



The soils of Tennessee, their chemical composition and fertilizer require- 

 ments, C. A. MooERs {Tennessee Sta. Bui. 7.s, pi). .'i7-90, map 1). — Chemical 

 analyses of 11.3 samples of typical soils from different parts of the State which 

 have been made since the publication of a former bulletin on soils (E. S. R., 10, 

 p. 2G) are reported, with discussion of general characteristics, classification, 

 and fertilizer requirements as indicated by analysis and fertilizer experiments. 



The samples were as a rule of two distinct classes "(1) virgin soils, either 

 from the forest or from newly cleared land, and (2) old lands, which, like the 

 majority of those under cultivation in the State, had not been modified by 

 previous manuring or fertilizing." The methods of analysis were essentially 

 those of the Association of Official Agricultural Chemists, potash, however, 

 being determined by Moore's direct method (E. S. R., 10, p. 408) and clay re- 

 moved from the ammonia extract in the determination of humus by settling and 

 repeated evaporation and resolution. 



A'general sui-vey of the State shows that " in passing from the eastern to the 

 westei'n limits of the State marked variations both in the soils and in the farm- 

 ing conditions are readily noticeable. In east Tennessee sharp contrasts occur. 

 The prevailing soils range in color from light gray to dark red, and in texture 

 from sandy loam to clay loam. Many of the valleys have the appearance of 

 being fertile and well farmed ; others are poor and abandoned. Some of the 

 hill lands are highly productive, and that others are of the oi)posite character 

 is evident at a glance. On the Cumberland Plateau is found a large area which, 

 although supporting a fair forest growth, has little durability under farm crop- 

 ping: On descending from the plateau there are found extending around tlie 

 central basin of middle Tennessee, and forming the outer part of the highland 

 rim, fertile, red-colored soils of limestone origin. Next to them, and forming the 

 inside of the rim, are the poor gray and yellow-colored soils of the barrens. A 

 marked change again takes place, however, when the rim has been crossed and 



