Temperature of the Air. 



265 



and considerably later in the other months, being about 2*' 40™ in June. If we group the months into the 

 astronomical quarters, we arrive at the following result : — 



Spring, maximum temperature, occurs at 1'' 40™ p.m. Makerstoun mean time. 



Summer, 1^ SO-" 



Autumn, l'' 50" 



Winter, 1^ 0™ 



Or, that the maximum temperature occurs later in the day at the equinoxes than at the solstices. It will re- 

 quire other years observations to prove the generality of this fact ; but it seems to bear some relation, and 

 that apparently not of difficult explanation, to the amount of the diurnal range of temperature. 



The mean temperature for the year occurs at 8^ 22™ a.m. 

 6^ 59™ P.M. 



The interval between these periods is lO'* 37™ 



The critical interval varies with each month, and is greatest in June, being 11^ 46™, and least in Feb- 

 ruary, being 8^ 11™. 



TABLE IV. — Errors of the Approximate Mean Temperatures for each Month and Quarter in 1843, 



deduced from one or two Daily Observations. 



Periods. 



True 

 Mean. 



Approximate Means ( + ) greater, or (-) less than true Means. 



Max. 



181" 



isl- 



191" 



SOI- 



sc 



21t 



22'» 



221' 



23h 



18'' 









and 



and 



and 



and 



and 



and 



and 



and 



and 



and 



and 



8^. 







Min. 



5^. 



6K 



6\ 



7". 



8\ 



Si. 



9i>. 



101-. 



10''. 



Qi. 







o 



o 



o 



O 



o 











O 



O 



O 



o 



o 



O 



January 



38-72 



+ 0-3 



+ 015 



-0-02 



-0-10 



-0-36 



-0-55 



-0-48 



-0-54 



-0-65 



-0-22 



+ 0-23 



-0-18 



February 



32-98 



+ 0-4 



+ 0-08 



-0-38 



-0-34 



-0-65 



-0-90 



-0-73 



-0-59 



-0-63 



-0-06 



+ 0-41 



-0-80 



March 



39-07 



+ 1-2 



+ 0-03 



-0-61 



-0-36 



-0-92 



-1-73 



-0-88 



-0-28 



-0-51 



+ 0-45 



-012 



-0-23 



April 



44-55 



+ 0-7 



-0-52 



-1-20 



-0-34 



-0-31 



-1-13 



+ 0-03 



+ 0-74 



+ 0-33 



+ 0-84 



-0-17 



-0-40 



May 



46-57 



+ 0-4 



-0-33 



-0-62 



+ 0-15 



+ 0-25 



-0-42 



+ 0-40 



+ 0-55 



-0-11 



+ 0-43 



-0-21 



+ 0-56 



June 



51-97 



+ 0-1 



+ 0-13 



-0-06 



+ 0-60 



+ 0-64 



+ 0-02 



+ 0-62 



+ 0-61 



-0-65 



-0-24 



-0-27 



+ 1-02 



July 



56-83 



+ 0-3 



-0-53 



-0-94 



+ 0-11 



+ 0-42 



-0-33 



+ 0-52 



+ 0-72 



+ 0-08 



+ 0-47 



-0-13 



-016 



August 



57-29 



+ 0-6 



-0-49 



-1-12 



-0-08 



-0-12 



-1-21 



+ 0-10 



+ 0-73 



+ 0-06 



+ 0-98 



-0-68 



+ 0-63 



September 



55-22 



+ 0-5 



-010 



-0-92 



-013 



-0-67 



-1-99 



-0-59 



+ 0-09 



-0-63 



+ 0-67 



-0-44 



+ 0-28 



October 



42-27 



+ 1-1 



-0-12 



-1-05 



+ 0-86 



-1-27 



-1-86 



+ 0-93 



-0-19 



-0-39 



-0-46 



+ 0-79 



-1-32 



November 



39-59 



+ 0-2 



-0-19 



-0-91 



-0-79 



-0-84 



-101 



-0-70 



-0-45 



-0-51 



+ 0-08 



+ 0-67 



-MO 



December 



45-26 



-0-3 



-0-23 



-0-53 



-0-52 



-0-58 



-0-66 



-0-27 



+ 0-07 



+ 0-02 



+ 0-24 



+ 0-36 



-0-49 



Spring 



43-40 



+ 0-8 



-0-28 



-0-82 



-0-19 



-0-33 



-1-10 



-0-16 



-0-34 



-0-11 



+ 0-57 



-0-18 



-003 



Summer 



55-36 



+ 0-3 



-0-29 



-0-70 



+ 0-21 



+ 0-31 



-0-50 



+ 0-41 



+ 0-58 



-0-17 



+ 0-40 



-0-36 



+ 0-50 



Autumn 



45-69 



+ 0-6 



-013 



-0-96 



-0-59 



-0-92 



-1-66 



-0-74 



-0-18 



-0-50 



+ 0-41 



+ 0-34 



-0-71 



Winter 



38-99 



+ 0-1 



0-00 



-0-31 



-0-32 



-0-52 



-0-70 



-0-50 



-0-36 



-0-42 



-0-02 



+ 0-33 



-0-49 



The Year 



45-86 



+ 0-5 



-0-17 



-0-70 



-0-25 



-0-36 



-0-98 



-0-24 



+ 0-09 



-0-30 



+ 0-34 



+ 0-04 



-0-18 



The 12 mon 



ths. 



























Mean of Ei 



•rors 



0-5 



0-24 



0-70 



0-36 



0-59 



0-98 



0-52 



0-46 



0-38 



0-43 



0-37 



0-60 



Range of E 



rrors 



1-5 



0-68 



1-18 



1-65 



1-91 



2-01 



1-81 



1-33 



0-98 



1-44 



1-47 



2-34 



The quantities given as the true means are from Table III. ; they are, therefore, only approximate, but 

 they must be very near the truth. The errors of the mean from the maximum and minimum thermometer are 

 obtained from Table II., after deleting the means for Sundays. The means for the odd hours were obtained 

 by taking the mean of the even hours between which the odd hours lie. 



The couple of hours best fitted for observations, in order to obtain the best approximation to the monthly 

 means, must CAadently be determined by 



1st, The smallness of the mean of the monthly eiTors, 

 2c?, The smallness of the range of the monthly errors. 



MAG. AND MET. OBS. 1843. 



3x 



