FIFTH ANNUAL MEETING. 



41 



From the preceding table it will be seen that the monthly tem- 

 peratures are subject to considerable variation. Thus, March and 

 November are sometimes winter months, while May and September 

 are occasionally summer months. The second half of May and the 

 first half of September almost invariably belong to the summer 

 season. 



The mean temperatures of the different seasons, together with 

 the mean annual temperature, are shown in the following table : 



Table II. — Mean Temperatures of Seasons and Years at Lawrence, Kansas. 



The mean annual temperature, as given in the preceding table, 

 does not differ essentially from that of the States to the east of 

 Kansas in the same latitude, viz.: Missouri, Southern Illinois, South- 

 ern Indiana, Southern Ohio, Kentucky, Virginia, and Maryland. 



The summers of Kansas, however, are somewhat warmer and the 

 winters considerably colder than those of the states just mentioned, 

 which is to be explained by the fact that the warm winds from the 

 heated, treeless plains on the southwest, arid the cold winds from 

 the snow-clad mountains on the northwest, sweep over Kansas with 

 little diminution of their original intensity of temperature. 



THE SUMMER SEASON. 



The average number of days on which the mercury reached or 

 exceeded ninety degrees during the five summers observed, was 

 thirty-eight. In the cool summer of 1869 there were only twenty- 

 three such days, while in the hot summer of 1870 there were forty- 

 six. But though the thermometer indicates a higher temperature 

 on a greater number of days in Kansas than in States in the same 

 latitude on the east, there are important compensations by which the 

 summer heat is, on the whole, as easily borne as in the eastern States. 

 In July, 1870, for instance, though the mean temperature at 2 p. m. 

 was nearly ninety-one degrees for the entire month, the nights were 

 invariably cool, the mean temperatures at 7 a. m. and 9 p. m. being 

 seventy-four and seventy-six degrees respectively. Another com- 

 pensation is the constant circulation of the air, which rarely becomes 

 calm in the summer season. Still another, and most important 

 modifier of the heat, is the dryness of our Kansas atmosphere, 



