6 TABLE OF CONTENTS. 



PAOB. 



III. Relation of forests to water supplies. By B. E. Fernow 123 



Tie total waf er supply 123 



Influence of forests upon precipitation 125 



Results of observations near Nancy, France 126 



Results obtained in Bohemia 126 



Results of observations in India and Brazil 128 



Supposed influence of forests upon bailstonns 129 



Influence of forests upon the disposition of the water supply 130 



Elements of dissipation 130 



Interception 130 



Evaporation 132 



Transpiration *. 136 



Elements of conservation 137 



Efl^ects of forests in case of snow 137 



General effect of forests in reducing evaporation 138 



Summation of the conservative and dissipative influences 140 



Distribution of terrestrial waters 141 



Analysis of determining influences 141 



Water capacity and water conductivity of soils and soil-cover.i .. 144 



Water conductivity of soils 148 



Formation of springs and conditions attecting their flow 153 



Influence of forests upon surfiice drainage 157 



Retardation of the waterflow 158 



Experience in the French Alps 159 



Examples of the influence of forests on waterflow 162 



IV. Notes on the sanitary significance of forests. By B. E. Fernow 171 



APPENDICES. 



I. Determination of the true amount of precipitation and its bearing on 



theories of forest influences. By Cleveland Abbe 175 



Relation of pattern and altitude of guages to accuracy of rainfall measure- 

 ments 1'76 



Elimination of errors of the rain guage 180 



Variations in geographical distribution of rainfall 182 



Chronological variations of rainfall 184 



Recommendations 185 



A]»p]icatiou to forestry 1^5 



II. Analysis of the causes of rainfall with special relation to surface condi- 



tions. By George E. Curtiss 187 



Climatic illustx'utions 189 



