374 
REPORT—1847. 
Upsides the correction already noticed for the diurnal variation of i! 
temperature corresponding to the particular hour or hours at which 
observations at a station have been made (which has only been appiiedui 
few sjvcified instances in the subjoined tables, as it appeare<l prefenblft 
give generally the original determinations independent of the currecw* 
the mean temperatures derived from the particular year or years dsw: 
which the observations were continued at each station, will require in ad 
case to be corrected for the non-periodic variation of the teraiterature i» 
year or years in (|uestion. On this subject the reader is referred to'-" 
preface and to pp, to 59 of Profe^r Dove's fourth memoir (euettW* 
above) in the Transactions of the Herlin Academy for 1847. Fwo t 
moan temperatures corrected for the diurnal and for the non^pm* 
variations, Professor Dove proposes to construct isothermal curvw ixai: 
moritii of the year, and lias expressed his inleiitiou of taking a future p(P 
tufiity of communicating the curves to the British .“issociaiioD; bulk* 
desirous that iu the mean time a few of the more striking phaenomeMshtJ 
have been brought into notice by this extensive assemblage and iuUtconip 
*u>n <)f the results of observation should be briefly indicated. 
I. The most novel at least, if nut the most important of these, htli*'' 
markable cosmical fact which they establish, of the existence of aaMi* 
variation in the aggregate mean temperature at the surface oftbp^ 
having its period of maximum during the sun’s northern declination, wd* 
nilniniutn during liis southorn declination. 
It we compare the temperatures at stations in the soutliern 
with Uiose of stations of corresponding latitude in tJie nortliei'i' 
we nud that it is generally the fact, that the sura of the siinultanpM*^ 
tempemturcs at the two stations iu the months of June, .hilyandAiJ^ 
(or ot those months wJiich constitute the northern summer and tlie s®" 
winter), is greater than the sum of the simultaneous mean tempers^’ ‘ 
cceniber, January and I’ebruary, or in the months which _ 
northern w-inter and southern summer. Let us take for exanipkl^ . 
Too**/!?/ temperatures in the seasons at Toronto, # 
♦J W and Ilobarton, latitude 42° 53' S., derived in each 
years of hourly observation at the magnetical and meteorologies 
^ stations; we have from 37,296 observations at Towoto> 
. 20 at Hobarton (Sundays not being days of observation) lhcwc*n 
perutures of the different seasons as follows 
Toronto. Hobarton. Sums. 
December, January, February. 
iVIarcli, April, May. 
September, October, NiverabVr 
June, July, August. 
25-43 
42-34 
46-81 
64-63 
61-79 
53*88 
53*76 
45*29 
87-22 
96*22 
100-57 
109*92 
fiwatl* 
-ii-ai 
^ ‘i-jti 
+ g<8 
+ I14t 
iNIean .. 98’48 
of comparison that the mean temperature of 
the Toronto + the mean 
the nTo^hs Tt exceeds by 22°-7 the mean 
or the .a.„e monr'at H^barLf 
a similar CQmpari.son be made of stations in South Amerio-^ 
