54 On the Climate of the Valley of the Mississippi. 



SuluLgo ' I « hr. Golden rod) Prairies, Aug. 13. July 28. 



Eupatorium c • sti-- mi, /. (Blue bone set) Barrens & bills, Aug. 15. Aug. 3. 



Helenium aulumrale, L. (Fake sun flower) Prairies & barrens, Aug. 23. Sept 7. 



From this comparison we obtain die mean result, that vegeta- 

 tion at St. Louis is less than two days earlier than at Washington 

 city. And allowing the correctness of the conclusion of Dr. Big- 

 elow, that a difference of about four days, correspond to a differ- 

 ence of one degree of latitude, we have here another striking proof 

 of the similarity of climate in these two different situations. 



If any importance can be attached to the observations and com- 

 parisons which I have detailed, I flatter myself that I have satisfac- 

 torily proved the truth of the position which I have laid down. I 

 invite a free and full examination of all that has been advanced, 



