On the Climate of the 



The eastern mountainous region consists of ranges of mountains 

 rising above each other, the highest of which is several thousand 

 feet above the level of the sea : it divides the waters of the east and 

 west, and forms the rampart or terrace between the first and third 

 regions. Its breadth is from 70 to 100 miles. It is but very par- 

 tially cultivated, being for the most part covered with vast and im- 

 penetrable forests. 



The third region includes, as I have before remarked, the vast 

 basin or valley, formed by the two ranges of mountains. The name 

 of the Mississippi basin is perhaps the most correct, as almost all 

 the streams which irrigate it, empty either directly or indirectly 

 into this stream. This basin may be considered as one continued 

 plain having but little elevation. The eastern portion, which is all 

 that need now be described, consists of a part of the state of Penn- 

 sylvania and the whole of Ohio, Indiana, Illinois, and Missouri. 

 It contains a great proportion of natural meadow, or what is termed 

 prairie land, entirely destitute of timber. It is as yet but thinly 

 settled and partially cultivated. 



Of the two last, nothing need be said, my object being merely to 

 compare the climate of the Atlantic coast with that of the valley of 

 the Mississippi. 



These brief and general topographical remarks, form a necessa- 

 ry preface to the more minute investigation of this subject. 



Thermometrical observations constitute the most common, and 

 perhaps the most correct method of ascertaining the temperature 

 of a climate. But in order to obtain a true result, these observa- 

 tions should be made with great care and be continued for a length 

 of time. Even after this, they form no criteria by which to judge 

 of the climate of a country, unless we know at what elevation, un- 

 der what circumstances, and in what manner, they are made. 

 Without a knowledge of these facts every thing is vague and un- 

 satisfactory. It is on this account that we are unable to employ 

 many thermometrical tables which have been kept, and which in 

 other respects appear correot. Hence a very limited number of plac- 

 es, particularly in the valley of the Mississippi, can be used in this 

 comparison. I regret, moreover, that I have not been able to pro- 

 cure sets of observations made under the same parallels of latitude 

 east and west. In order to make up for this deficiency it will be 

 necessary to resort to a method, which, although somewhat arbitra- 

 ry is less liable to objection than any other. It has been adopted 



