1849.] exercised by Trees 071 Clunate. 453 



Dr. Forry remarks on the above passage that " it is unsustained 

 by any well observed facts." 



Dr. Webster, another American writer on the climate of N. 

 America, arrives from a most extensive investigation of historical 

 facts at the conchision, " that the winters have been from the first 

 settlement of America variable ; now mild, now severe, just as 

 they are in the present age." A leading object with him is to 

 show the error of Dr. WiUiams, who, having maintained that the 

 mean temperature of Italy " has increased 17^, wished to establish 

 some analogous change in our climate since its occupation by Eu- 

 ropeans, and Doctor Webster proves most conclusively, that, if 

 Doctor Williams is unfortunate in his facts, he is still more so in 

 his reasonings and deductions." 



Dr. Webster concludes with the following passage as ' the re- 

 sult of clearing the forests. — From a careful comparison of these 

 facts he says, it appears that the weather in modern winters is 

 more inconstant, than when the earth was covered with wood at 

 the first settlement of Europeans in the country ; that the warm 

 weather of autumn extends farther into the winter months, and the 

 cold weather of winter and spring encroaches upon the summer," &c. 



Dr. Forry concludes his interesting paper with the following re- 

 marks : that climates are susceptible of melioration by the ex- 

 tensive changes produced on the surface of the earth, by the labors 

 of man, has been pointed out already; but these effects are extreme- 

 ly subordinate, compared with the modifications induced by the strik- 

 ing features of physical geography, the ocean, lakes, mountains, the 

 opposite coasts of continents, &c." 



Again: " The fallacy of the opinion which ascribes the mild cli- 

 mate of Europe to the influence of agricultural improvement becomes 

 at once apparent, when it is considered, that the region of Oregon 

 lying west of the rocky mountains, which continues in a state of pri- 

 mitive nature, has a climate even milder than that of higlily cultivat- 

 ed Europe in similar latitudes; and again, China situated like the 

 United States on the eastern coast of a continent, though subjected 

 to cultivation for several thousand years, possesses a climate as ri- 

 gorous, and some assert even more so, than that of the United States 

 on similar parallels." 



It is singular, however, that in the foregoing elaborate paper, no 



