286 ABSTRACTS OF THE MAKERSTOUN OBSERVATIONS, 1843. 
TABLE XXIII.—Continued. 
The means in this Table have been obtained from the daily observations by the following formula :—The 
observation at 18" being that of the maximum pressure of wind which has occurred from 10 of the previous 
evening (excepting Monday mornings, when it is the maximum pressure which has occurred from about noon 
of the previous day), the observation at 18" may be used as the maximum pressure belonging to some one 
couple of hours in the previous morning (excepting on Mondays), M being the daily means of ‘the maxima in 
the previous Table, S the sum of the nine daily observations, 10, the maximum observed at the 10" preceding 
the 18" observation, 10, the maximum obseryed at the 10" succeeding the 18" observation, then 
mS +10, #20 + 10, 
For Mondays the means have been obtained by the formula 
9 4+ 3 x 20 + 10, 
12 
M = 
where S’ is the sum of the eight observations from 20 till 10"; the observation at 18" obviously could not be 
used for the daily means on Mondays. 
The means of the four daily observations were taken for the daily means in the first week of January. 
Annual Variation of the Means of the Maximum Pressures of the Wind.—The greatest monthly mean is 
that for January, being 2-02 Jb., and the least is that for September, being 0°321b. The pressure diminishes 
from January till March, when there is a minimum, the means for the four months following being greater ; it 
increases from September to December, The following are the means for the three groups of seasons, namely, 
The mean meteorological seasons, for which June, July, and August constitute summer. 
The meteorological seasons for 1843, for which July, August, and September constitute summer. 
The astronomical seasons, for which May, June, and July constitute summer. 
Seasons. Mean Meteorological. Meteorological for 1843. Astronomical, 
Ib. Ib. lb. 
Spring, cD ian 0-76 0:96 
Summer, ‘ ; 0°58 0°45 0-68 
Autumn, 4 ; 0-72 1:08 0°52 
Winter, : ‘ 1:62 1:34 1:47 
Range of Means, . 1:04 0-89 0:95 
The pressure is greatest in the coldest quarter and least in the warmest quarter of 1843. 
The mean for the year of the maximum pressures = 0°91 lb. 
