384 EXPERIMENT STATION RECORD. 



untbrax spores on skins in tanneries it is considered necessary that they be 

 treated with formaldebyde for from 6 to 14 days by the addition of 0.5 to 1 per 

 cent of formaldehyde to the liquid in which the skins are kept. This strength 

 of formaldehyde will destroy the anthrax spores, but unfortunately it injures 

 the skins to such an extent that they are not suitable for commercial use there- 

 after. Formaldehyde is, therefore, not a practical disinfectant for use in this 

 connection. Similarly in using corrosive sublimate, lysol, lysoform, and cresols 

 the objection is found that poisonous effects are experienced by workmen who 

 handle skins treated in this manner, and also that the leather is somewhat 

 injured. The experiments thus far carried on have not led to a practical 

 method for the disinfection of skins. 



RURAL ENGINEERING. 



Irrigation, J. J. Vernon (Xeic Mexico 8ta. Rpt. 1906, pp. 2-9-38).— This 

 report covers the irrigation experiments made at the New Mexico Station in 

 cooperation with this Office during 190.5. The experiments included a compari- 

 son of cost and results in irrigating with river water and with water pumped 

 from wells. With alfalfa the yields were slightly larger where river water was 

 used, although the cost of producing the alfalfa was but 62 cts. per ton with 

 river water and $4.40 per ton with pumped water. On the other hand, the 

 yield of tomatoes irrigated with well water was three times as large as that 

 from i)lants irrigated with river water, while the expense was but 50 per cent 

 larger. 



Evaporation records were kept, the total evaporation for the year being 58 

 in., estimating the evaporation for two weeks in July not covered by the records. 



Tests were made of four pumping plants, one using a steam engine and three 

 with gasoline engines, in two of which naphtha, was used for fuel instead of 

 gasoline. Efficiencies of the engines were remarkably uniform, varying from 

 71 to 78.54 per cent. The efficiencies for the entire plants are not given. The 

 fuel cost per foot-acre-foot with the steam engine with coal at .$5 per ton was 

 G.89 cts., with gasoline at 19.5 cts., 7.27 cts., and with naphtha at 1.3.5 cts., 5 cts. 

 for one of the plants, and 17 cts. for the other. 



Irrigation investigations, E. Nelson (Idaho *S7o. Bill. 58. pp. J/G, ftos. 2). — 

 This bulletin gives the results of irrigation investigations carried on in 1900 in 

 cooperation with this Office. The work was confined to the Twin Falls tract in 

 south central Idaho on the Snake River and included soil-moisture determina- 

 tions before and after irrigating, in connection with observations on the condi- 

 tions of the crops to determine the water-holding capacity of the soil, the 

 degree of wetness most conducive to plant growth, and the amount of w^ater 

 which can be applied at a single irrigation without waste. 



It v,'as found that the maximum water capacity of the Twin Falls vsoils was 

 24.72 per cent by weight and 43.69 per cent by volume, or sufficient to cover 

 the land to a depth of 5.24 in. for each foot of soil. The unbroken soil was 

 found to be moist at a depth of only 18 in. and contained 5.78 in. of water in 

 the first 3 ft. Land irrigated the preceding season contained in the spring 10 

 in. of water in the first 3 ft. It was found that irrigated land can hold by 

 capillarity 10 in. of water in 3 ft. The average quantity of water used on first- 

 year land was 21.88 in. and on the second-year land 17.84 in., the average 

 amount applied in a single irrigation being 7.84 in. 



The furrow system of irrigation is used on 90 per cent of the land in the 

 Twin Falls tract, the furrows being made 20 to 24 in. apart. The cost of clear- 

 ing land and preparing it for irrigation and for seeding is given as $10.50 per 

 acre. The average yields per acre reported are : Wheat, 45 bu. ; oats. 80 bu. ; 

 potatoes, 250 bu. ; corn, 30 bu. ; alfalfa, first year, 1 ton ; second year, tons. 



