482 



H. MOHN. METEOROLOGY. 



[noRW. POL. EXP. 



The mean minima and maxima of the temperature in the different months 

 stand thus (Tables, pp. 403-468 and PI. III. 1 mm. = 1° C): 



The aperiodic diurnal range of the temperature of the air has an 

 annual period with maxima in February and October, and minima in July 

 and December. The summer time has the smallest range, the most constant 

 temperature. We find the greatest range in the winter half-year, particularly in 

 February, and at the equinoxes. December has a secondary minimum. The 

 smallest range occurs in July. The time about the equinoxes is the most 

 unsteady as regards the diurnal temperature; the time about the solstices 

 is steadier, that about the summer solstice being the steadiest. The aperio- 

 dic diurnal range is measured by from 2° to 8°, the periodic range from 

 0°2 to l-°7. (PI. III. 1 mm. = 1 ° C). 



