ECOLOGY OF ISLE ROYALE. 



43 



TABLE NO. 2.— PORT ARTHUR, 1896-1905. 

 Rainfall. 



Snowfall. 



These climatic records are likely to mean little when taken by them- 

 selves, but when compared with the conditions found in the other extreme 

 of the state, interesting relations become apparent. Transeau ('05 b, 

 pp. 356-358) has summarized the temperature and precipitation means 

 for certain localities in southeastern Michigan, and these means have 

 been placed in the table with the Port Arthur data. The most striking 

 difference (Table 1) is the much higher temperature throughout the 

 jear in southern Michigam; the mean July maximum is 71.9° as contrast- 

 ed with 62.24° at Port Arthur; the annual mean is 47.2° as contrasted 

 with 36.07° for Port Arthur. The northern mean is between the tem- 

 perature of the maximum density of water (39.2°) and the freezing point. 

 "The precipitation presents almost equally striking differences. The rain- 

 fall instead of being largely confined to the summer months, as at Port 



