SEVENTH ANNUAL MEETING 59 



Day, Francis, 1886. The Effects of an Elevated Temperature 

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Heath, Neil, 1883. Effect of Cold on Fishes. U. S. F. C. Vol. 4, pp. 

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Kidder, J. H., 1879. Report of Experiments on Animal Heat of 

 Fishes. Proceedings U. S. Nat. Mus. 1879, p. 306. 



Pictet, Raoul De, l'emploi methodique des basses temperatures 

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Shelford, V. E. and Allee, W. C, 1913. The Reactions of Fishes 

 to Gradients of Dissolved Atmospheric Gases. Jour. Exp. Zool., Vol. 

 14, No. 2, February 1913. 



Wells, M. M., 1913. The Resistance of Fishes to Different Con- 

 centrations and Combinations of Oxygen and Carbon Dioxide. Biol. 

 Bull. Vol. XXV., No. 6, Nov. 1913. 



EVAPORATION AND SOIL MOISTURE IN FORESTS 

 AND CULTIVATED FIELDS 



J. F. GROVES, UNIVERSITY OF CHICAGO 



I. Evaporation. Considerable work has recently been done 

 in the Chicago region by Fuller 1 and others on the evaporating 

 power of the air in such natural plant associations as the Cot- 

 tonwood, Pine and Oak dunes, Edaphic prairie and Beech- 

 Maple forest. In this work the beech-maple forest has been con- 

 sidered the most satisfactory standard for comparison of other 

 plant associations and it has therefore been used in this paper 

 as a basis for comparing the evaporating power of the air in 

 cultivated fields. The region near Otis, Indiana, offers ex- 

 cellent conditions for such a study and is accessible to Chicago, 

 therefore it has been selected for this work. The beech-maple 

 forest for this investigation is bordered by cultivated fields of 

 wheat and oats which have soils of a similar nature. The 

 methods of cultivation in the wheat field are evidently superior 

 to those in the oat field, as indicated by the greater depth of 

 humus and the texture of the soil. The evaporating power of 

 the air and the soil moisture of these habitats has been de- 

 termined during the season extending from May 3 to August 

 23, 1913. 



In determining the evaporation power of the air the Living- 

 ston 3 porous cup atmometer was used according to the usual 

 methods employed. All instruments were properly standard- 

 ized before being set up and at frequent intervals during the 

 season. By comparison of these coefficients with that of a 

 standard atmometer, all readings were reduced to a common 



