1898— 1902. No. 4.] TEMPERATURE. DAILY PERIOD. 



Ill 



Month 



Minimum 



Maximum 



Range 



M. O. 



January . 

 February 

 March 

 April . . 

 May . . 

 June . . 



July • ■ 

 August . 

 September 

 October . 



November 



December 



hour 

 h m 



5 44 P-m- 

 8 12 p. m. 

 7 24 a. m. 

 3 34 a. m. 

 2 48 a. m. 



2 22 a. m. 



3 33 a- m- 



4 34 a- m- 

 o 15 a. m. 

 o 30 a. m. 

 7 22 a. m. 

 2 43 a. m. 

 o 43 p. m. 



4 13 a. m. 



5 42 p. m. 



hour 

 h m 



6 48 a. m. 



I o p. m. 



1 38 p. m. 



2 54 p.m. 



3 12 p. m. 

 2 40 p. m. 



2 40 p. m. 



3 57 P- m- 



1 16 p. m. 



4 o a. m. 

 3 30 p. m. 



8 22 a. m. 



7 o p. m. 



2 IS p. m. 



9 50 p. m. 



am. 



o 

 + 0.14 



+0.18 



+ 1.10 



+ 1.79 



+ 1-45 

 + 0.81 

 40.88 

 + 0.97 

 + 0.52 

 — 0.09 

 + 0.25 



-f O.II 



+ 0.07 

 4-0.08 

 4-0.17 



0-34 

 0-37 

 1.91 



3-47 

 3-09 

 1. 71 

 1.76 



1-75 

 0.89 

 0.41 



0.26 



0.32 



0.08 



O.II 



0.51 

 1. 14 

 0.96 



0-53 

 0.52 

 0.51 

 0.26 

 0.16 



0.06 



0.08 



The Table shows that there is no regular solar diurnal period 

 in the months October, November, December and January. The last 

 row in the foregoing Table, headed "Dark Season" shows the mean for 

 November, December and January, or the dark season, in which the 

 sun is totally below the horizon. It will be seen that no regular daily 

 period comes out. In the months from February to October we have 

 the ordinary period with minimum (except in February) in the morning 

 or night, and maximum some hours after noon. 



The daily range has an annual period. It is greatest (3.47) in 

 April, and vanishes in the dark season. The three summer months have 



o o 



nearly the same range of 1.7 to 1.8. 



The mean ordinate has the same period. Its amount is about one 

 fourth of the daily range in the winter months, and about one fourth 

 to one fifth in the summer months. 



The effect of the amount of cloud upon the daily period of the tem- 

 perature of the air is shown in the following Tables. The bi-hourly 

 observations of the temperature have been taken out separately for the 

 clear days (daily mean of amount of cloud less than 2) and for the 

 days with sky overcast (d. m. o. a. 0. c. above 8) and their means 

 taken for each hour, and reduced to noon. The number of clear and 

 overcast days is given in the Table. The Table also' shows the daily 

 means of the 12 bi-hourly observations, the daily minimum and maxi- 

 mum, hour and value, and their difference or the daily range. The 

 minimum and maximum have been taken from smoothed curves. The 



