CONTENTS AND ARGUMENT. 



FAOE. 



Index to Authorities Cited, xi 



Pbbfaob, xiii 



States circumstances in which the volume is published. 



Inteoduction, - - - - 5 



States subjects to be discussed as being more particularly the effect of 



forests on the humidity of the climate, including the rainfall ; but 



treating this only as accessary to other effects, and these such as 



may be produced by every blade of herbage according to its 



PAET I. — Phenomena of Vegetation on which the Mbtbor- 

 OLOGioAL Effects of Forests affecting the Humidity 

 OF Climate depend, 3 



Chapter I. — Primary Phenomena of Vegetation, 3 



Primary phenomena of vegetation are expounded as seen in the Hed 

 Snow, the Yeast plant, Confervie, and Alges (pr. 3), and' thus is 

 illustrated the absorption of moisture by endosmose (p. 5), which 

 process is more fully detailed (p. 6). The liquid ab&orbel is^ traced 

 from the rootlets to the leaves (p. lOj ; the rise of the sap is ex- 

 plained in accordance with the supposition of its being attributable 

 to endosmosic action (p. 12). The difference between this and 

 capillary attraction is explained (p. 13), and the difference between 

 this and what is called vis a tergo (p. 15). The structure of the 

 leaf is described (p. 17), and the process of the evaporation of the 

 moistmre by the stomates of the leaves is illustrated (p; 19). 



