472 



II. MOHN. METEOROLOGY. 



[NORW. POL. EXP. 



October has the lowest minimum at 7 a. m. and the highest maximum 

 at from 1 to 2 a. m. A second maximum occurs at 3 p. m. and a third at 

 10 a. m. In general the day is colder than the night. 



November and January have the minimum in the afternoon, and the 

 maximum in the morning hours. 



December has a lowest minimum at 9 a. m. and a highest maximum 

 at 1 — 2 a. m. There is a second maximum at 2 p. m. The day is colder 

 than the night. 



February has two minima, at 1 p. m. and at 9 p. m., a highest maximum 

 at 7 a. m., and a second maximum at 5 p. m. The day is colder than the night. 



Taking the means of D. f. m. for the 12 months in which the sun was 

 entirely below the horizon (Oct. 1895, Nov. 1893, 94, 95, Dec. 1893, 94, 95, 

 Jan. 1894, 95, 96, Febr. 1895, 96) we obtain 



Minimum — 0-°23 at 2'^18'^p. m. Maximum + 0-°20 at 0'>49'» a. m. 



Mean ordinate 0-°14. Range 0-°43. 



Mean Latitude 82°53'. Mean Longitude 90°59'. 



The march of the temperature during 24 hours comes out very regularly, 

 and with a single period. Day is colder than night. The range is small, 

 but distinctly defined both in amount and direction. (PI. IIL 1 cm. = 1°). 



The solar diurnal period of the temperature of the air vanishes in the 

 dark season. The period shown by the observations during this time must 

 be ascribed to other causes than the radiation from the sun. The radiation 

 from the twilight may have some effect, and this must tend in the same 

 direction as the radiation of the sun. A period with the day colder than 

 the night must have a different origin. We have seen (p. 278) that in 

 the dark season the north component of the wind's frequency exceeds the 

 south component uninterruptedly from 7 a. m. to 8 p. m. The wind-roses 

 for the temperature of the air show, as will be found later, that in the dark 

 season the northerly winds are colder than the southerly winds. It seems 



