FISHERIES, GAME AND FORESTS. 425 



A detailed study of the Iowa tests shows that clover makes a very constant demand 

 upon the soil for moisture, due possibly to some extent to the nature of the soil, but 

 also due to the fact that clover is a uniform feeder, sending its roots to a great depth 

 in the soil. The experiments in the corn field indicate that the demands of corn from 

 August 6 to 20 were very large. The experiments on the oat field indicate that the 

 demand for water is the largest near the surface. The root crop yielded 17.5 tons per 

 acre, which indicates a consumption of 1.2 1 inches of water on the ground area per 

 ton of crop. In the blue grass meadow the consumption of water was very large, 

 being somewhat greater than for clover. 



In regard to the preceding experiments at the Wisconsin and Iowa Agricultural 

 Colleges, it may be pointed out that probably in the dry climate of those States the 

 amount of water transpired by plants is greater than under the more humid conditions 

 of the eastern states. In any case the figures are valuable, not only as verifying the 

 results of foreign investigators, but because they give results obtained under the 

 conditions of climate in the United States. 



EXPERIMENTS OF BALDWIN LATHAM. 



Baldwin Latham, the English Sanitary Engineer, has stated* that beginning in 

 June, 1870, he discharged sewage upon a definite area, planted with ray-grass, at the 

 Beddington-Croydon sewage farm, the grass being so placed in a water-tight tank six 

 inches deep, and provided with suitable underdrains, with means of collecting the run- 

 off of the drains, that definite results could be obtained. From June 18, 1870, to 

 June 12, 1 87 1, a period of 360 days, during which time 20.03 inches of rain fell, the 

 water evaporated from a square yard of surface amounted to a depth of 186.3 inches 

 over the area in a year. Experiments on another plat during the year 1871-72, gave 

 for a period of 370 days, with a rainfall of 24.98 inches, a total application of water 

 amounting to a depth of 91.2 inches over the area. These experiments indicate what 

 large quantities of water may be evaporated by grass crops, provided a full 

 supply is furnished. 



EVAPORATION FROM LONG AND SHOi^.T GRASS. 



Observations as to the evaporation from grass crops have been made at Emdrup, 

 Denmark.f According to these observations the mean evaporation from a water 

 surface for a period of eleven years was 27.9 inches. The mean evaporation from 



* In discussion of Mr. O'Meara's paper "On the Introduction of Irrigation in New Countries, as 

 Illustrated by Northern Colorado." Proc. Inst. C. E., Vol. LXXIII (1893). 

 f See Beardsmore's Manual of Hydrology, p. 296. 



