1138 EXPERIMENT STATION RECORD. 



degree of purification attained with the best intermittent filters under the best 

 operating conditions. . . . 



"Along with this recognition of the varying requirements of sewage treatment are 

 many new suggestions concerning the methods to be followed. The most interesting 

 of these to the engineer who has not been following the development of the subject, 

 is the closer connection which is gradually appearing between the principles of water 

 purification and sewage treatment." 



Present practice in sewage disposal (Engin. Rec, 53 (1906), No. 4, pp. 97, 98). — 

 This is a summary of a paper presented by G. W. Fuller at a recent meeting of the 

 New Jersey Sanitary Association. 



The paper emphasizes the desirability of preparatory treatment with raw sewage 

 to remove the sludge, combinations of methods of purification, and treatment of the 

 effluents with copper sulphate or other germicides, and describes comparative tests 

 which have been made by the city of Columbus, Ohio, of various methods of sewage 

 disposal. The preparatory treatment found most effective in these trials was afforded 

 by septic tanks holding an average flow of about 8 hours, followed by the use of 

 sprinkling filters operating at an average rate of 2,000,000 gal. per acre daily. 



The collection and preservation of samples of sewage for analysis, S. DeM. 

 Gage and G. 0. Adams (Jour. Infect. Diseases, 1906, Feb., Sup. 2, pp. 139-148).— 

 Chloroform in amounts of 10 to 25 cc. to each gallon bottle is stated to"beagood 

 preservative for samples of sewage which are to be kept for some time before analysis. 



SOILS— FERTILIZERS. 



Some new properties of soils, J. Konig, J. Hasenbaumer, and E. Coppenrath 



(Landw. Vers. Stat., 63 (1906), Xo. 5-6, pp. 471-478). — This article discusses briefly 

 the effect of steam on soils and the catalytic power and osmotic pressure of soils. 



It is shown that by heating 250 gm. of a soil with 3 to 4 liters of water for 3 hours 

 under a pressure of 4 atmospheres the solubility of the" mineral constituents was 

 increased to a considerable extent. Similar treatment acts like mercuric chlorid, 

 chloroform, etc., in reducing the oxidizing or catalytic power of soils, which is 

 ascribed to the action of oxydases (catalase) as well as bacteria. A device consisting 

 of a Chamberland-Pasteur filter coated with gelatin rendered insoluble by the action 

 of formaldehyde fumes for study of the osmotic power of soils is described, but no 

 experiments with it are reported. 



A study of rock decomposition under the action of water, A. S. Cushman 

 (Chem. News, 93 (1906), No. 2410, pp. 50-53).— This is a discussion of this subject 

 based largely upon investigations which have already been noted (E. S. R., 17, p. 301). 



Data are presented to show that electrical endosmosis offers an efficient means of 

 separating not only water but also acids or alkalis from slimy, colloidal, and other- 

 wise unfilterable mixtures such as are obtained with very fine rock powders. It is 

 shown that by successive grindings and treatment with an electric current the potash 

 can be removed irom orthoclase and other minerals containing potash. 



In the experiments reported "definite weights of the rock powders were slimed 

 w r ith a measured quantity of water, and the slime placed inside an ordinary unglazed 

 porcelain cup such as is used lor certain common types oi bell batteries. An ordi- 

 nary arc-light carbon was then inserted and the porcelain cup set down inside a glass 

 cylindrical vessel containing distilled water to the depth of 2 or 3 cm. Another car- 

 bon electrode was then inserted in the outside compartment. The cell was then con- 

 nected with a direct current of about 110 volts, the inner or slime chamber being in 

 connection with the positive pole. 



" Under the action of electrical endosmosis all the liquid from the anode or slime 

 chamber passed into the cathode chamber, while at the same time, owing to elec- 

 trolysis, the free alkali passed out in a condition in which it could be easily titrated 

 or otherwise estimated. In the course of a few hours the slime had been transformed 



