*15 
SECOND REPORT- 1832. 
The mean hour of minimum temperature for the year is 5 h O' 
a.m. ; that of maximum temperature, 2 h 40' p.m. 
The deviation of any pair of hours of the same name* from 
the mean of the day, is less than 0°*5 Fahr. And of all pairs 
of hours, 4 a.m. and p.m. are the most accurate. 
The reduction of the results of any register made at regular 
hours, in this climate, to the mean temperature of the day, is 
readily deduced. 
The mean annual temperature of any hour never differs more 
than 3°*2 from the mean of the day for the whole year. 
The mean daily range is a minimum at the winter solstice, 
and a maximum in April. The mean daily range in this climate 
is 6 o, 065. The result of the two years agree within of a 
degree, though the mean temperature was considerably dif¬ 
ferent. 
By dividing the curve of daily temperature into four parts, 
by the maximum and minimum points and the points of mean 
temperature, the intermediate portions of the curve may be 
accurately represented by parabolic arcs. 
On the whole, these most interesting results give us an in¬ 
sight into what may be done, by multiplying observations, to¬ 
wards bringing the science of Temperature under calculation. 
An interesting series of comparative observations were under¬ 
taken at Christiana under the superintendance of Professor 
Hansteen, during the warmest and coldest month of the year 
1827f. The result is very striking. The daily variation of 
temperature at Christiana is in February 12°*01 F. ; in July, 
12°*09. At Leith, in the former month it is only 3°*57 ; in 
the latter, 9 0, 68. The annual variation is also immensely greater 
at Christiana than at Leith : 
Christiana. Leith. 
Mean of February . . 16 0, 224 40°*621 
-——-July . . . 61 *690 60 *361 
Difference . . 45 *466 19 *740 
These are striking illustrations of the difference of a conti- 
nental and an insular climate. 
The curves of diurnal and annual temperature have been 
investigated by Professor Hallstrbm of Abo, but before the 
appearance of the above-mentioned observations ; he was led to 
* “ Heures homonymes,” Humboldt. This author has observed that the 
same results are deducible from the Padua observations. Fragments Asiatiques, 
iis 420. 
f Edinburgh Journal of Science, ix. 309. 
