450 EXPERIMENT STATION RECORD. 



nitrogen rarried by tin- iliaiii waters is only a little more jx-r acre-foot tlian the 

 potash, it ])eing o.S lbs. . . . 



"We tiiid the total solids in tlie return waters lower tlian in the ground waters, 

 and having the same range as found for the drain waters We find them charaeter- 

 ized by the same salts, and in the same order in regard to their relative quantities, 

 i. e., calciimi sulphate, magnesium sulj)hale, and sodium carbonate, with sodium 

 sulphate irregular in its cpiantity, Init always subordinate, except in the samjjle of 

 Arkansas River water taken at Rockyford, April 24, 1903, concerning which some 

 doubts maybe c~ntertained, but which is probably correct, T)ecause the ground waters 

 of that section are extremely rich in sodium sulphate. . . . The cliief difference 

 between the drain waters and the return waters taken from the rivers is in the potash 

 I)resent, whit-h is greater in the return waters than in the drain waters. While some 

 of the drain waters contain almost as much potash as the return waters, the latter 

 are, as a rule, ri('her in potash than the former. The inain features of these two 

 classes of waters are, however, identical." 



The amount of suspended matter in the water of the Cache la Poudre with a flood 

 flow of 12,000 second-feet was found to be 2,800 tons per hour. Chenncal analyses 

 of this sediment showed it to differ but slightly in composition from the soils from 

 which it was derived, being slightly richer in organic matter. 



The underground ■waters of Arizona — their character and uses, W. W^. Skin- 

 ner [Arlzomi Stu. Bui. 4'>, PP- '-71-.'96, Ji<jx. ^) . — "This l)ulletinis a compilation and 

 discussion of the results of an examination of the ground waters of the Territory as 

 to their suitability for sanitary, irrigation, and tec-hnical uses." The results of 

 analyses of 235 miscellaneous samples of water collected in different parts of the Ter- 

 ritory are reported. Some of these analyses are of special interest from sanitary and 

 technical points of view, but there is not a sufficient number from any one point to 

 permit of definite conclusions regarding the character of any local supply. 



The purification of water supplies by slow sand filtration {Jour. Aiiier. Med. 

 Assoc, 51 {1903), Nos. 14, pp. 850-853; 15, pp. 909-911; 10, pp. 965-967; 17, pp. 1025- 

 1027,fifjs. 9). 



Report of the chemical laboratory of the Ploti Agricultural Experiment 

 Station, B. M. Wklbel {Rap. An. Sia. Expt. Agron. Plotij, 8 {UiO.i), pp. 69-116, 

 chart 1). — The work of this laboratory during 1902 followed substantially the same 

 lines as in previous years (E. S. R., 14, p. .340). The data reported show that the 

 average nitrogen content of the atmospheric precipitation during 3 years, 1900-1902, 

 was 0.924 mg. per liter, or 3.9 kg. per hectare (3.5 lbs. per acre) in 1900, 5.2 kg. 

 (4.6 lbs.) in 1901, and 3.7 kg. (3.3 lbs.) in 1902. The larger proportion of the 

 nitrogen was in the form of ammonia. The ammonia content of different kinds 

 of precipitation was found as an average of 3 years' observations to be as follows: 

 Snow 0.915 mg. per liter, rain 0.964, rain with storms 1.229, early and late frost 

 {geUe hlanche) 2.7, hail 2.75, hoar frost {givre) 4.2, dew 5, and fog 5.57. 



A study of the progress of nitrification in the soil under different conditions, by 

 means of lysimeters 50 by 50 cm. in size, showed that from one-fifth to one-fourth 

 of the water received in form of precipitation was recovered in the drainage. 

 Taking only the days during which the temperature to a depth of 10 to 25 cm. did 

 not fall below 5° C, the daily jiroduction of nitric nitrogen per hectare is calculated 

 to have been 501 gm. in soil on which summer wheat had l)een grown and which had 

 received no fertilizer or manure, 821 gm. in manured soil under sunmier wheat, and 

 876 gm. in soil bearing alfalfa. The production of nitric nitrogen in black fallow was 

 about the same as in the manured soil. 



Assuming that there are 125 days favorable to the production of nitric nitrogen in 

 the soil during the period of growth of winter wheat, the author estimates that the 

 first soil above referred to would furnish for this crop 63 kg. of nitric nitrogen per 

 hectare (56.1 lbs. per acre), the second 103 kg. (91 lbs. ), and the third 110 kg. (98 lbs. ). 



