LIMITS AND METHOD OF EXPOSITION. 47 



properly so called, in its most restricted sense. We here 

 consider phsenomena only in their mutual connection, and 

 in their relations to the different zones of our planet, 

 and to its general physical constitution. The specialities 

 either of inanimate substances or of organic beings, classed 

 according to analogy of form and composition, do indeed 

 form a highly interesting subject of study, but quite foreign 

 to the present work. 



Particular descriptions of countries are, it is true, the most 

 available materials for a general physical geography ; but the 

 most careful successive accumulation of such descriptions 

 would be as far from affording a true picture of the general 

 conformation of the irregular surface of our planet, as a 

 series of all the floras of different regions would be from 

 forming what I should designate by the term of a " Geo- 

 graphy of Plants." It is the work of the intellect, by 

 comparing and combining isolated observations, to extract 

 ^om the specialities of organic formation (morphology and 

 the descriptive natural history of plants and animals,) that 

 which is common to them in regard to their climatic distri- 

 bution ; to investigate the numerical laws, or the proportion 

 of certain forms or particular families to the whole number 

 of species ; to assign the latitude or geographical position of 

 the zone where (in the plains) each of these forms reaches 

 its maximum number of species, and its highest orgpnift 

 development. These considerations will lead us to perceive 

 the manner in which the picturesque character of the land- 

 scape in different latitudes, and the impression which it pro- 

 duces on the mind, depend principally on the laws of the 

 geography of plants, or the relative number and more vigorous 

 growth of those wLich predominate in the general mass. Tha 

 YOL, J, * 



