of Reducing Observations of Temperature. 25 
The names of stations are entered in the order in which 
they occur in the Society’s Reports, being nearly that of lati- 
tude, proceeding from north to south. 
The first column of numbers contains the values of A, or 
the mean annual temperature obtained in the usual manner. 
In the second and third columns are the values of a and e 
(amplitude and epoch) determined in the manner already ex- 
plained. 
The fourth column shows the number of days and tenths of 
a day by which each station is earlier or later (as regards the 
phases of its temperature) than the mean of all; days earlier 
than the mean being denoted by +, and days later by —. 
The fifth column exhibits the difference between the mean 
temperatures of the warm and cold halves of the year. 
The numbers in the 4th column have been obtained from 
those in the 3d, by taking the difference from the mean value 
of e for all the stations (79° 20’), and converting it into days 
at the rate of 1° to 1,,d day. (Since 360 : 365: : 72: 73). 
The numbers in che oth column are proportional to those 
in the 2d, and have been obtained from them by the formula 
log. a + :1099 = log. n. (Since :1099 is the logarithm of 
1:2879). 
To find the centres of the warm and cold halves of the year, 
we may proceed as follows. The mean value of e for all the 
stations is 79° 20’. To reduce to the beginning of the year, 
subtract 15°, since our reckoning has been taken from the 
middle of the first month. This leaves 64° 20’, which is the 
interval from the beginning of the cold half to the end or 
beginning of the year. The complement of this, or 25° 40’ 
is the interval from the beginning of the year to the centre of 
the cold half, which again is 180° distant from the centre of 
the warm half. 
25° 40’ corresponds to 26 days (nearly.) 
205° 40’ 55 209 is 
The 26th and 209th days of the year are January 26th and 
July 28th, which are therefore the centres of the cold and 
warm halves of the year for the mean of the stations. The 
corresponding dates for any particular station will be earlier 
_or later than these by the amount shown in column 4. 
NEW SERIES.—VOL. XIV. No. 1.—JsuLy 1861. D 
