340 EXPERIMENT STATION RECORD. 



considered best to allow it to accumulate in considerable quantity since precipitation 

 is more complete in its presence. 



Purification and sterilization of drinking- water by means of calcium 

 peroxid, L. Fkeyssinge and R. Roche {Rev. Internal. Falsi/., 18 (1905), pp. 49-51; 

 a/**. in Jour. Chem. S<>r. [London], 88 (1905), So. 51\, II, p. 515).— It is stated that 

 water can be completely sterilized by adding 0.4 gm. of calcium peroxid per liter. 

 The action is not instantaneous, hut in most cases takes about 2 hours. 



The process is hastened ( requiring about 15 to 20 minutes) by the addition of a 

 small amount of sodium hydrogen carbonate which rapidly decomposes the peroxid. 

 The hydrogen peroxid as well as the precipitate of calcium carbonate formed by the 

 decomposition of the calcium peroxid maybe removed by filtering through manga- 

 nese dioxid. The hardness of the water is generally reduced by this treatment. 



SOILS FERTILIZERS. 



Studies on the properties of an unproductive soil, B. E. Livingston, J. C. 

 Brittox, and F. R. Reid { U. S. Dept. Agr., Bur. Soils Bui. 28, pp. 39).— -The soil used 

 in these experiments is described as "a brownish-yellow coarse sandy loam, 3 ft. or 

 more in depth, resting upon material similar to the Susquehanna clay. Samples 

 taken at intervals from the surface downward show a gradually increasing proportion 

 of silt and clay." 



The mechanical analysis shows that "the soil is rather peculiar in that it possesses 

 relatively large amounts of coarse and of fine material, but only small quantities of 

 medium-sized particles." Chemical analysis ( by digestion in hydrochloric acid, sp. 

 gr. 1.115) showed potash 0.135, lime 0.145, and phosphoric acid 0.11 per cent. The 

 water extract of the soil contained calcium 11.7 parts per million of air-dry soil, 

 potassium 22.7 parts, phosphate (P0 4 ) 7.0 parts, and nitrate (N0 3 ) 5.5 parts. The 

 soil contained 3 per cent of organic matter and 0.1 per cent of nitrogen. Native and 

 cultivated plants growing on the soil exhibited peculiar structures similar to those 

 observed in case of a soil subject to drought. 



A series of experiments was made with this soil in small wire baskets described in 

 previous publications of the Bureau (E. S. R., 17, p. 227). In these experiments the 

 influence of the water supply and of different manurial substances was studied. The 

 results show that wheat seedlings were much stunted even when the water content 

 was kept at the optimum (14-17 per cent) throughout the period of growth, indi- 

 cating that the unproductive character of the soil is not due to lack of water. 



It was showm that the soil was "improved to a great extent by the addition of fer- 

 mented stable manure, green manure (consisting of the stems and leaves of cowpeas), 

 sumac and oak leaves, tannic acid, pyrogallol, calcium carbonate, and ferric hydrate. 

 . . . With the exception of nitrate of soda, ordinary fertilizers have no beneficial 

 effect. When wheat seedlings are grown in aqueous extracts of this soil they make 

 the same kind of growth as in the soil itself. The stunting power of the extract can 

 be corrected by the addition of extract of stable manure, pyrogallol, calcium carbon- 

 ate, ferric hydrate, and carbon black." 



The authors conclude that these facts show that the soil "contains a water-soluble 

 nonvolatile substance or substances, probably organic in their nature, which are 

 toxic to wheat plants, causing a stunting of their growth. The toxicity of the soil 

 is corrected by the use of stable manure, green manure, leaves of sumac, oak, etc., 

 tannic acid, pyrogallol, calcium carbonate, ferric hydrate, and carbon black." 



A method for the mechanical analysis of soils, T. Crook (Econ. Proc. Roy. 

 Dublin Soc, 1 (1904), Xo. 5, XIII, *>}>. 267-280, figs. 2).— In the method here pro- 

 posed the separations are performed by means of a modification of the Schone appa- 

 ratus, the essential features of which are (1) a constant-level water reservoir which 

 can be adjusted to any desired height; (2) an elutriator which differs from the 

 Schone apparatus in being conical both above and below the cylindrical portion; 



