406 



Results of Makeestoun Observations, 1844. 



TABLE II. — Hourly Means of the Temperature of the Air for each Month in 1844. 



It should be remarked, that the changes of temperature l>ctween ll"^ 10'" p.si., and 12'' 10"' a.m., are 

 slightly inaccurate in Table II.; this is due to the variations of temperature between 11'' 10"" p.m. of the 

 Saturdays, and 12'' 10"' a.m. of the ilondays, and to the dift'erence between the temperature at 12'' 10'" a.m., 

 the first hour of the month, — and ll"" 10" p.m., the last hour. The changes of temperature between ll"" 10'" 

 P.M., and 12'' 10"' a.m., as determined by the observations for eacli month, where the interval was only one 

 hour, are as follow, namely, temperature at 12'' 10"" a.m., minus temperature at 11'' 10'" p.m.: — 



Jan. Feb. March. .Vpril. 



O'.OO -0°-15 -0°'20 -0°-24 



May. .lune. -'uly. 



_0°.85 -0'-39 -0°-77 



Aug. Sept. Oct. Nov. Dec. Year. 



-0'-.33 -0°-47 -0°-36 +0°-18 + 0°-05 -0°-30 



The changes actually exhibited in Table II. are — 

 -0'-9 -0^-9 -C-T -0°-l -T-1 -0°-7 -T-S 



O'^'O 



.0°-6 -C-S +0"1 +0'-4 -0°-55 



Diurnal Variation of Temperature. — When the true changes of temperature at midnight are remembered, 

 it will be seen that in the three months of November, December, and January, the temperature varies little 

 more than 0''5 for five or six hours before and after midnight ; the minimum in these months, therefoi-e, is not 

 very distinctly marked. The following are the approximate epochs for each month of 1844 : — 



.Ian. Feb. March. April. May. .lune. .IliIv. -^"g. .Sept. Oct. 



Min. A.M. o''10"' 2''— 4'' 6'' 10™ 4'' 30™ 3*^ W" S"" 10" 3'' 30'" 4'' 30™ 4'' 30™ S*" 10" 

 Max. P.M. 1'' 30™ l*" 40™ 2'' 20'" 2'' 10™ 2'' 10™ l"" 10™ 3'' 10™ 1'' 30™ 1'' 30"' 2'' 0™ 



Nov. Dec. 



10i'_4'' 10''— G* 

 P 20™ 1'' 20™ 



The following Table contains the means for the astronomical (juarters (November, December, and January 

 being winter), and for the year. 



