254 Dependence of the Geographical Belations of Gauntries 



America ; that they had a temperature lower by at least 4° or 

 5° R. (from 9° to 11° F.) than it is now ; that the banks of the 

 Tiber were as cold as those of the River Seine, at present ; 

 that the banks of the Po, in point of temperature, resembled 

 those of the Caspian Sea ; and that, in general, the large forests 

 of Italy and of the southern parts of France, formerly gave 

 rise to a climate entirely different from what it is now-a-days. 

 In accordance with these facts, Italy, owing to the quantity of 

 moisture produced by its forests, may have resembled the 

 United States ; and France, the woody territories of the 

 northern parts of Europe. 



By careful comparisons we may gain a knowledge of the 

 changes, which, in virtue of the contrasts visible in the phy- 

 sical condition of countries, have affected the various relations 

 of the races occupying the different portions of our globe. 

 All the material interests of nations are intimately connected 

 with that physical condition, nay, they positively depend on it. 

 Through the medium of this latter, they are also influenced 

 by the variations in atmospheric moisture, which are, as we 

 have seen, in a great measure, the direct result of the action 

 of forests. Moreover, the immaterial interests are thus indi- 

 rectly brought under its control, a circumstance deeply affect- 

 ing the welfare of all the European, and, in particular, the 

 German nations. Comparative geography furnishes the most 

 satisfactory evidence of this peculiar and thorough connec- 

 tion between the physical condition of countries and all the 

 geographical relations of the population, and it deduces these 

 proofs especially from the influence which forests exert on 

 the elements just alluded to ; as also on the fertilization of 

 the soil, which, on account of the importance recently at- 

 tached to the seriously and broadly discussed population-ques- 

 tion, play a very prominent part in modern science. We 

 ought not to neglect the circumstance, that forests contribute 

 in various ways to the production, preservation, and accumu- 

 tion of a fruitful soil, either by preventing the rich mould and 

 alluvial soil from being washed and carried off the slopes of 

 mountains, the waters of the sea from making irruptions, the 

 sand of deserts from being scattered about, and the ground 

 from becoming exhausted ; or by influencing the condition of 



