816 EXPERIMENT STATION EECOED. 



June 5. 1912, is reported. The average of free ainmoiiia in snow was 3.35 

 parts per million, in rain 0.931 part per million; alluminoid ammonia in snow 

 3.84 parts, in rain 1.13 parts; nitrite nitrogen in snow 0.0021 part, in rain 

 0.0018 part ; nitrate nitrogen in snow 0.19 part, in rain 0.15 part. The average 

 of the chlorin in the rain and snow was about 4.8 parts per million. It is 

 estimated that the total amount of nitrogen carried down to the soil in rain 

 and snow during the period named was 6.27 lbs. per acre. 



The sterilization, of water by ultraviolet rays, A. Silbebmann {Ztschr. 

 Hyg. u. InfekPionskrank., 77 {1914), No. 2, pp. 189-216, fig. I). — The general 

 conclusion reached from the investigations here reported is that sterilization 

 of drinking water by means of the quartz mercury vapor lamp is entirely 

 practicable provided precautions are taken to insure the proper working of the 

 apparatus. These precautions are set forth in some detail. 



A bibliography of references to the literature of the subject is given. 



Metropolitan sewage farm, A. M. Laughton (Victorian Yearbook, 33 {1912- 

 13), pp. 260-264)- — This is a brief account of the farm used in purification of 

 the sewage of Melbourne, with data regarding its operation and efficiency. 



The total area of this farm is 9,153 acres. The land is prepared for sewage 

 disposal by division into paddocks of 20 acres each, seeded to alfalfa or peren- 

 nial grasses (mainly prairie or rye grasses). "With the exception of a few 

 hundred acres of lucern reserved for hay, the land is grazed with sheep, cattle, 

 and horses, the practice being to keep the stock shifting from block to block to 

 eat the feed down in front of the sewage water." The principal business is 

 " the fattening of store sheep, but the grazing and farming operations are sub- 

 servient to the main object of the farm, viz, the filtration of the equivalent of 

 about 7.1 ft. of sewage per acre per annum." 



The area actually under irrigation in 1911-12 was 4,932 acres; the area 

 available for sewage disposal was 5,894 acres. The average daily quantity of 

 sewage delivered to the farm was 31,066.653 gal. The revenue from grazing 

 amounted to £15,245 ($76,225). The net cost of sewage purification during the 

 year was £8,736 ($43,680) or 3.7 d. (7.5 cts.) per capita of population. 



SOILS— FERTILIZERS. 



Estimation of the surface of soils, J. A. Hanley (Jour. Agr. Sci. [England], 

 G (1914), No. 1, pp. 58-62, fig. 1; abs. in Jour. Soc. Chem. Indus., 33 (1914), 

 2io. 4^ V- 210). — Several methods of estimating the surface area of soils are 

 noted and tests of the dye method described by Ashley (see p. 807) and by 

 Konig, Hasenbaumer, and Hassler (E. S. R.. 26, p. 519) are reported. 



Comparisons of the quantities of dye removed by sandy loam, loam, and clay 

 loam soils from methyl violet dye solutions of 12 different strengths varying from 

 0.25 gm. to 3 gm. per liter showed that in all cases the dye absorbed increased 

 rapidly with an increasing strength of dye solution up to a certain point when 

 the soil appeared to become almost saturated, indicating " that if dye solution of 

 one strength be used the three figures obtained can not be comparable. ... To 

 obtain relative values indicating the active surfaces of different soils it is 

 necessary that each soil be brought into equilibrium with a solution of the 

 same strength. ... It is necessary to use . . . not the same strength of dye 

 solution throughout but such a strength for each soil as will leave it when dyed 

 in equilibrium with the same dye solution. . . . [Also] the relative values for 

 different soils ought to be the same whatever the concentration of the final 

 solution." Curves indicating the quantities of dye absorbed by the same soils 

 " when in equilibrium with solutions of strengths varying by 0.0125 gm. per 100 

 CO. from 0.0125 to 0.125 gm. per 100 cc. . . . [show] that the values on the 



