402 



H. MOHN. METEOROLOGY. 



[nORW. POL. EXP. 



The spirit minimum thermometer and the mercury maximum thermometer were set 

 every day at 8 a. m. and at 8 p. m. Immediately before setting the minimum thermometer, 

 the top of the spirit column and the outer end of the index were read. The first of these 

 readings, compared with the simultaneous corrected reading of the dry thermometer, gave the 

 correction of the minimum thermometer. This correction was applied, and the lowest 

 temperature thus found between midnight and midnight was taken as the day's minimum. 

 When observations with the minimum thermometer were wanting, the minimum adopted 

 has been taken from the corrected thermograph-curve. When the minimum tempera- 

 ture, found from the corrected reading of the minimum thermometer, was higher than 

 the lowest temperature from the corrected thermograph-curve, the latter has been adopted. 

 In some cases the lowest temperature was found at midnight. This minimum tempe- 

 rature has been taken for both the preceding and the following 24 hours. 



The maximum thermometers proved to be remarkably correct when compared 

 with the dry thermometer at rising temperatures. When the temperature was below 



TEMPERATURE OF THE AIR. C 



1893. OCTOBER. 



