TEMPERATURE OF THE AIR. 265 
and considerably later in the other months, being about 25 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, .: 
Autumn, ........ 
WWYATEELS ia sia siesonacasamete an ncesede. slisich oaks 
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™ an. 
Se gnIRGOSE inset eeteristcceiseesicas c'scatgars-e beset On OOTME Ne 
The interval between these periods is 10" 37 m 
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. 
—_—_—_—_—_——ank eee ee 
Approximate Means (+) greater, or (—) less than true Means. 
. True 
Periods. Mean. || Max. 1gh 18h 19» 20 20 21 22h 22h 23h 18h 
and and and and and and and and and and and 8h, 
Min. 5h, 64, 6h, 7, 8h, CL 9h, 104, 104, oh, 
° ° ° o ° ° ° ° ° ° fo} ° ° 
January 38-72 || +0-3 |+0-15 |—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 | —0-12| — 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]—0-16 
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 |—0-10|—0-92 | —0-13 |—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 | —1-01 | —0-70 | — 0-45 |—0-51 + 0-08 | + 0-67 | — 1-10 
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 | — 0-03 
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 |—0-13 | —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 months, a 
Mean of Errors 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 Errors 15 | 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 evidently be determined by 
1st, The smallness of the mean of the monthly errors, 
2d, The smallness of the range of the monthly errors. 
MAG. AND MET. obs. 1843. 3x 
