PRESSURE OF THE WIND. 287 
TABLE XXIV.—Daily, Weekly, and Monthly Means of the Pressure of Wind in Pounds on the 
Square Foot of Surface, deduced from the greatest Pressures observed within 10™ az the hours 
of Observation. 
March. 
0-03 
0-25 
0:39 
The means in this Table have been obtained from the nine observations by the formula already given, 
Table I., for the temperature of the air. The daily means in the first week of January are the means of the 
four daily observations. 
Annual Variation of the Means of the Maximum Pressures of Wind at the Hours of Observation.—Naming 
these pressures the mean pressures, for which they may be taken approximately, we find the same law of varia- 
tion as for the maximum pressures. ‘The mean pressure is greatest for January, the mean being 1-29 Ib.; it 
diminishes till March, in which there is a minimum, the means for the four months following being greater ; 
the least pressures occur in August and September, the mean for the latter being 0°16 lb. ; the pressure then 
increases till December. The following are the means for the three groups of seasons :-— 
Seasons. Mean Meteorological. Meteorological for 1843. Astronomical. 
1b. lb. lb. 
Spring, 2 0-40 0°43 0°56 
Summer, ; é 0°31 0°23 0:38 
Autumn, ; a 0°35 0°54 0°25 
Winter, ae “OE 0-83 0.83 
"Range of Means, . 0°65 0-60 0-58 
