ECOLOGICAL CROSS SECTION OF THE MISSISSIPPI. 



131 



From the temperature table given (A) the following data 

 have been calculated. The mean covers the period from 

 1874 to 1907. The seasonal division here made is: spring, 

 March, April, May; summer, June, July, August; autumn, 

 September, October, November; winter, December, January, 

 February. 



TABLE D. 



Seasonal Mean 



Annual 

 Mean 



Extremes 



^ 



Winter 



Spring 



1 



Summer 



1 



Autumn 



Maximum 



1 



Minimum 



33.94 



55.55 



' 77.18 



52.67 



56.47 



107 



-22 



AVERAGE AND EXTREME TEMPERATURE. 



A comparison of normal temperature and precipitation 

 for St. Louis, given by Fippin and Drake,* is reproduced as 



Table E. 



TABLE E. 



f Month 



Temper- 

 ature 



Precipi- 

 tation 



1 



Month 



Temper- 

 ature 



Precipi- 

 tation 



January 



February 



March 



April 



May 



June 



30.5 

 35.1 

 43.1 



56.2 

 65.8 

 75.2 



2.18 

 2.78 

 3.49 

 3.79 

 4.58 

 5.08 



July 



A ugust 



September 



October 



November 



December 



78.8 

 76.8 

 69.4 

 57.5 

 43. G 

 35.6 



3. 76 

 3.50 

 3.12 



2.89 

 3.10 

 2.81 



1 



NORMAL TEMPERATURE AND PRECIPITATION. 



It is almost unnecessary to state that figures obtained 

 for various stations in our section show marked differ- 

 ences. Even where conditions are fairly uniform the 

 differences are striking. This is well illustrated by Table F, 

 containing figures taken from a paper by Nipher.f 



* Fippin, E. 0. and J. A, Drake. Soil Survey of the OTallon Area, 

 Missouri-Illinois. Rept. U. S. D. A. Bureau of Soils. 6 : 817. 1904. 



t Niplier, F. E. Report on Missouri Rainfall, witli Averages for ten 

 Years ending December, 1887. Trans. Acad. Sci. St. Louis. 5: 383. 

 1889. 



