NO. 17.] 



TEMPERATURE OF THE AIR. 



489 



The columns 1, 2 and 3 show a very decided annual period (PI. III. 

 1 mm. = 1 ° C). The interdiurnal variability is greatest in the winter time ; 

 the maximum lies in February, and is lowest in July. The numbers form 

 a very regular curve. The mean rising for the year is a little lower than 

 the falling. The time during which the temperature is rising, is longer than 

 its time of falling; it rises more slowly than it falls. The means for the 

 3'"'^ column are 



Winter Spring Summer Autumn 



± 3°-85 ± 2°-83 + 0°-83 ± 3°-27 



The next Table gives the mean number of cases (days) in which the 

 mean diurnal temperature has changed from one day to the next from 0° 

 to 0-°9, from 1 to l-°9, etc. 



o o 



0-1 



o o 



2-3 



o o 



3-4 



o o 



4-5 



O O 



5-6 



O o| O O 



6-7 7-8 



O O 



8-9 



9-10 



10-11 



11-12 



12-13 



13-14 



15-16 



16-17 



17-18 



21-22 



Jan. 



Febr. 



Mar. 



Apr. 



May 



June 



July 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



Winter 

 Spring . 

 Summer 

 Autumn 



Year . . 



8-7 



5-7 



5-3 



7-0 



11-3 



18-0 



26-0 



22'0 



8-5 



4-8 



4-7 



4-7 



4-7 

 3-7 

 6-0 

 7-3 

 8-3 

 8-0 

 5-0 

 4-5 

 5-5 

 6-0 

 5-3 

 5-7 



3-3 



3-7 

 3-7 

 4-7 

 4-0 

 2-3 



2-5 

 8'0 

 7-2 

 4-7 

 4-3 



3-3 



2-7 

 3-7 

 3-3 



2-7 

 1-0 



1-5 

 3-5 



2-4 

 4-0 

 6-0 



2-7 

 2'7 

 2-0 

 3-7 

 1-3 

 0-7 



0-5 

 20 

 2-0 

 3-0 

 2-3 



3-3 



1-7 

 2-7 

 2-3 

 2-3 



0-5 



2-8 

 2-3 

 "3-3 



ro 



1-3 

 1-3 

 0-7 

 0-7 



10 

 2-4 

 1-3 

 10 



1-7 

 1-3 



2-0 

 0-3 



0'5 

 20 

 2-0 

 1-0 



1-3 

 1-3 

 2-0 

 0-3 



0-8 

 0-3 

 10 



0-3 

 1-0 

 1-0 



0-3 



0-5 

 0-8 

 1-0 

 10 



1-0 

 0-3 



0-3 



0-7 



ro 



1-0 

 0-3 



0'3 



0-3 



0-4 

 0-3 

 0-3 



0-8 



0-3 



0-3 



Per month. 



0-3 



0-3 



01 



002 



The smallest interdiurnal variations are of the greatest frequency. In 



winter the variation reaches 21°. This was the case from the 20**^ to the 21^* 



February, 1896, when the mean diurnal temperature rose 21'° 8, from — 40'°8 



62 



