956 



EXPERIMENT STATION RECORD. 



WATER SOILS. 



Evaporation observations in the United States, II. H. Kimball {Mb. Weather 

 Rev., 32 {1904), No. 12, pp. 556-559, fig. 1 ). — This paper, which was read before the 

 Twelfth National Irrigation Congress at El Paso, Tex., November 16-18, 1904, sum- 

 marizes observations in the United States, especially those of D.Fitzgerald" at 

 Boston, Mass., L. G. Carpenter at the agricultural experiment station at Fort Collins, 

 Colo., T. Russell at various signal service stations, E. Stelling at St. Petersburg, and 

 by the United States Weather Bureau in different parts of the United States, par- 

 ticularly in cooperation with the United States Geological Survey. The formulas of 

 Fitzgerald, Russell, and Carpenter for computing evaporation are discussed. 



"The equations of Fitzgerald and Carpenter appear to have a quite general appli- 

 cation, provided we know the temperature of the water surface, the dew-point, and 

 the wind velocity. It would seem, therefore, that in the absence of reliable meas- 

 urements of evaporation from water surfaces, an effort should be made to determine 

 the temperature of water surfaces near Weather Bureau stations, and where the 

 evaporation is measured from tanks sunk in the ground the relation between the 

 temperature of this evaporation surface and the temperature of lakes or reservoirs in 

 the vicinity should be carefully determined. 



"Seasonal evaporation naturally varies with geographical position. Some of its 

 peculiarities are shown in the following table:" 



Evaporation in incites. 



"The above table indicates the importance to irrigation engineers of making the 

 readings throughout the entire year." 



Analyses of waters, <i. E. Colby {California Sin. Rpt. 1904, pp. 84-48). — This 

 article reports and discusses the results of analyses of 144 samples of water from dif- 

 ferent sources in the State. 



Soil investigations, H. Snyder and J. A. Hummel {Minnesota Sta. Bui. 89, pp. 

 191-212, pis. 2) . — This bulletin gives the results of 3 investigations relating to the 

 fertility of soils as follows: (1 ) The influence of crop rotations and use of farm ma- 

 nures upon the humus content and fertility of soils, (2) the water-soluble plant food 

 of soils, and (3) the production of humus in soils. 



The first of these investigations is a continuation of work previously reported upon 

 (E. S. R., 13, p. 540) and yives a summary of studies during 1900-1904, "of the effects 

 upon the fertility of 12 years continuous cropping compared with crop rotations and 

 the use of farm manures." These studies show "that when grains are grown con- 

 tinuously there is a heavy loss of nitrogen from the soil, caused by decay of the 



"Trans. Amer. Soe. Civ. Engin., 15 (1886), p. 581. 



