294 
Abstracts of the Makerstoun Observations, 1843. 
In forming the sums for January in Table XXIX., the following quantities, estimated from the four daily 
observations, were used as belonging to the first week in that month : — 
Wind. 
Times. 
Sums of Pressure. 
Wind. 
Times. 
Sums of Pressure. 
lb. 
lb. 
NNW. 
1 
0-2 
W by S. 
2 
3-0 
NW by W. 
4 
2-4 
SW by W. 
15 
13-4 
NW. 
5 
4-3 
ssw. 
5 
3-2 
W. 
9 
6-2 
Annual Variation of the number of times which the Wind blew, as deduced from the observations made 
at 9 two hourly intervals. The following are the sums of the times which the wind blew at the observation 
hours for each month, as obtained from Table XXIX. : — 
Jan. Feb. March. April. May. June. July. Aug. Sept. Oct. Nov. Dec. 
177 149 127 135 170 187 161 113 113 159 126 173 
The number of times which the wind blows is a maximum in January, the number diminishes to March 
when it is a minimum, it increases to June when it is a maximum, diminishes again to August and Septem- 
ber when it is a minimum, and increases till December when the number is nearly the same as in January. 
The only exception to the regularity of this increase and diminution is in November, in which month the num- 
ber is less than in October. In the year 1843 the ivind blew most frequently at the solstices and most seldom 
at the equinoxes. The range of the variation of the numbers is 74, or § of the greatest number, 187, that for 
June. 
Annual Variation of the number of points of the compass in which the Wind blew. — The following are the 
number of points of the compass in which the wind blew for each month : — 
Jan. Feb. March. April. May. June. July- Aug. Sept. Oct. Nov. Dec. 
17 17 24 27 20 25 24 21 29 24 20 9 
The wind, therefore, seems to be least variable at the Winter solstice, and more variable at the equinoxes 
than at the summer solstice. 
Annual Variation of the sums of the Pressure of the Wind. — This, of course, is the same as has been 
already obtained, Table XXIV., for the means of the pressures ; or the maximum near the winter solstice, 
minima at the equinoxes, and a secondary maximum near the summer solstice. The sums, as obtained from 
Table XXIX., are as follow : — 
Jan. Feb. March. April. May. June. July. Aug. Sept. Oct. Nov. Dec. 
lb, lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. 
261-6 191-4 82-9 122-9 111-6 106-4 91-4 52-2 45-8 100-3 111-6 171 5 
Annual Variation of the Mean Pressure of the Wind when blowing. — The means, Table XXIV., are tin- 
mean pressures throughout the 24 hours. The following means are obtained by dividing the sums of the 
pressures by the number of times which the wind blew :— 
Jan. Feb. March. April. May. June. July. Aug. Sept. Oct. Nov. Dec. 
lb. lb. lb. lb. lb. lb. lb. lb. Ib. lb. lb. lb. 
1-48 1-28 0-65 0-91 0-66 0-57 0-57 0-46 0-41 0-63 0 89 0-99 
The mean pressure of the wind when blowing is a maximum in January and December ; it is a minimum 
in September. There is also a minimum in March, but it is not sufficiently marked to produce a distinct maxi- 
mum near the summer solstice, as shewn by the sums of the pressures. From this the wind seems to blow 
with the greatest force near the coldest, and with the least, force near the hottest period of the year. The range 
«0f the Monthly means of the pressure of wind while blowing is 1-07 lb. 
