Temperature of the Air. 



40' 



TABLE III. — Hourly Means of the Temperature of the Air for each Astronomical Quarter, 



and for the Year 1844. 



Mak. 



Nov. 



Feb. 



May 



Aug. 





Mak. 



Nov. 



Feb. 



May 



Aug. 





M T 



Dec. 



March 



June 



Sept. 



Year. 



M T. 



Dec. 



March 



June 



Sept. 



Year. 





Jan. 



April. 



July. 



Oct. 







Jan. 



April. 



July. 



Oct. 





h. 











o 



h. 









o 







12 



36-20 



35-73 



47-57 



47-13 



41-66 







39-50 



44-23 



58-67 



56-90 



49-82 



13 



36-27 



35-57 



47-10 



46-77 



41-42 



1 



40-07 



44-77 



59-17 



57-27 



50-32 



14 



36-13 



35-23 



46-57 



46-33 



41-07 



2 



39-83 



44-93 



59-07 



57-23 



50-27 



15 



35-97 



35 03 



46-20 



45-97 



40-79 



3 



38-93 



44-37 



58-83 



56-70 



49-71 



16 



35-87 



34-80 



46-43 



45-67 



40-69 



4 



37-87 



43-17 



58-07 



55-67 



48-69 



17 



35-77 



34-90 



47-53 



45-63 



40-96 



5 



37-23 



41-53 



5700 



53-67 



47-36 



18 



35-90 



35-27 



49-57 



46-53 



41-82 



6 



36-77 



40-10 



55-50 



52-30 



46-17 



19 



36-10 



36-23 



51-67 



48-07 



43-02 



7 



36-73 



38-87 



53-80 



50-83 



45-06 



20 



36-20 



37-83 



53-53 



50-37 



44-48 



8 



36-43 



38-00 



51-77 



49-70 



43-97 



21 



36-73 



4003 



54-83 



52-57 



46-04 



9 



36-37 



3713 



50-43 



48-70 



43-16 



22 



37-63 



4213 



56-37 



54-43 



47-64 



10 



36-17 



36-60 



49-33 



48-00 



42-52 



23 



38-60 



43-40 



58-07 



55-90 



48-99 



11 



36-33 



36-30 



48-60 



47-60 



42-21 



These means give the following epochs of minimum and maximum :- 





Winter. 



Spring. 



Summer. 



Autumn. 



Year 1844. 



Min. 



5 h 10 m A.M. 



4 h 30 ra a.m. 



3 h 20 m a.m. 



4 h 50™ A.M. 



4 h m A.M 



Max. 



l h 20 m P.M. 



2 h m p.m. 



l h 25 m p.m. 



l h 40 m p.m. 



l h 30 m P.M 



The minimum temperature occurs earliest in summer, and latest in winter ; it occurs about 3 hours be- 

 fore sunrise in winter, 2 hours before it in spring, ^ hour in summer, and about 1 hour before sunrise in 

 autumn. The maximum temperature occurs nearest noon in winter, and nearer noon in summer tban at 

 the equinoxes. This result was obtained from the two hourly observations for 1843, p. 265. 



In order to examine the variations of temperature about midnight in the winter group, we may connect 

 the mean at 12 h with that at ll h , by means of the corrections given above; from these, the mean at 12 b in 

 winter is greater than the mean at ll h , by o, 08; from this, and the above means for the winter group, we 

 find the variations of temperature from 9 h 10 m p.m., till 3 h 10 m , to be as follow : — 



9 h 



0°-20 



10" 

 0°-00 



lH 



0°-16 



12 h 

 0°-24 



1^ 

 0°-31 



0°-17 



3 h 

 0°-01 



From these, there appears to have been a secondary maximum of temperature in winter at l h 10 m a.m., 

 the secondary minimum occurring at 10 h 10 m p.m. This result is exhibited in the means for each of the 

 months November and December, and also in those for January, the true change from ll h to 12 h being 

 considered. 



The maximum temperature for the year 1844 occurs at the same hour as for 1843, — namely, 1 ,! 30 m p.m. 

 The mean temperature for each month occurs at the following times : — 



Jan. Feb. March. April. May. June. July. Aug. Sept. Oct. Nov. Dec. 



AM 9 h 34m p,h7m 8 h 49 m 8 h 22m 8 h 5 m 7 h 34 m 7 h 33 m 8 h ll m 8 h 10 m 8 h 51 m 8 h 56 m 10 h 5 m 



p.m.,"...... 5 55 6 8 7 4 7 8 7 42 7 28 7 50 7 18 7 16 6 41 5 5 6 



Intervals, 8 21 9 1 10 15 10 46 11 37 11 54 12 17 11 7 11 6 9 50 8 4 7 1 



The intervals are greatest in the three months constituting the astronomical summer, and least in the 

 three months constituting the astronomical winter. December has the least, and July bas the greatest, critical 

 interval. The following are the epochs of mean temperature for the astronomical quarters : — 



Winter. 



a.m., 9 h 33™ 



p.m., 5 31 



Intervals, 7 58 



Spring. 



Summer. 



Autumn. 



Year 1844. 



8 h 38 m 



^h 44 m 



8 h 23 m 



8 h 26-5™ 



7 3 



7 42 



7 10 



7 18-3 



10 25 



11 58 



10 47 



10 51-8 



