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 Pres8)ire 



NNW. 

 Why W. 

 NW. 

 W. 



1 



4 

 6 

 9 



lb. 



0-2 

 2-4 

 4-3 

 6-2 



W by S. 

 SW by W. 



SSW. 



2 



15 



5 



lb. 



3-0 



13-4 



3-2 



Annual Variation of the number of times which the Wind blew, as deduced from the obseirvations 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 wind blew most frequently at the solstices and most seldom 

 <xt the equinoxes. The range of the variation of the numbers is 74, or | of the greatest number, 187, that for 

 June. 



Amnviol 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. 



rb. 



lb. 



lb. 



lb. 



lb. 



lb. 



lb. 



lb. 



61-6 



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 the 

 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. 



lb. 



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- 

 anum 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 

 of the monthly means of the pressure of wind while blowing is 1 -07 lb- 



