298 



Absteacts of the Makerstoun Observations, 1843. 



After the number of the times which the wind blew, and the sums of the pressures for the observation 

 hours, the sums of the times blowing and pressures for all the 9 observations are given, and next the sums of 

 the times blowing and pressures for 12 observations, three times the mean of the sums for IS** and lO*' being 

 taken as the sums for the three observations wanting to complete the day. The following quantities have also 

 been made use of in forming the sums for 12 observations : — 



Direction. 



Times. 



Sums of Pressures. 



Direction. 



Times. 



Sums of Pressures 



NNW. 



NW by N. 



NW. 



W. 



I 



6 



5 



12 



lb. 

 0-2 

 2-7 

 4-3 



7-7 



Why S. 

 SW by W. 



SSW. 



2 



18 



5 



lb. 



30 



14-9 



3-2 



These being estimated for the first week of January, and for the observation at 1 8^, omitted in the second week. 



Diurnal Variation of the number of the times which the Wind blew in 1843. — The following are the sums 

 of the number of times which the wind blew, at each observation hour, with a pressure of one-tenth of a pound 

 or upwards on a square foot of surface, as obtained from Table XXXI. : — 



5h lOn.. 7h 10m. 9h 10m. Hb 10m ^.M. \^ lO-" P.M. S^ lO™. 



5h 10.n. 



7h lO"-. 



9^ 10« 



138 166 205 233 256 242 212 171 126 



Differences, 28 39 28 23 14 30 41 45 



The number of times which the wind blew increased from 5^ 10"° a.m. till !•* 30™ p.m., the interpolated 

 period of maximum, and diminished from I'* 30'*i p.m. till 9^ 10™ p.m. The number increases most rapidly 

 about 8*" A.M., and diminishes most rapidly about 8^ p.m. The wind, therefore, blew most frequently exactly 

 at the time of the maximum temperature of the air. 



Diurnal Variation of the number of Points of the Compass in which the Wind blew. — The numbers of the 

 points of the compass in which the wind blew at the observation hours, are — 



51, lOm 

 27 



71, 10m 



27 



9'^10'». llh 10" A.M. II" 10m P.M. 3h 10m. 



30 



29 



31 



30 



Si 10n>. 



30 



1^ 10"-. 

 26 



9^ 10"'. 



25 



The wind, therefore, seems to blow less steadily from 9 a.m. till 5 p.m. than before the former and after 

 the latter of these hours. 



Diurnal Variation of the Sums of Pressures of the Wind. — This, of course, is the same as that of the 

 means, Table XXVII., or a maximum about 25™ after Noon. The sums are as follow : — 



o^ 10". 



7^ 10". 



gi" 10". 



ll"" 10" A.M. 1"" 10" P.M. 



3^ 10". 



oh 10". 



7^ 10". 



9h lOm. 



lb. 



lb. 



lb. 



lb. 



lb. 



lb. 



lb. 



lb. 



lb. 



59-5 



133-5 



170-4 



211-5 



224-0 



192-1 



156-1 



118-7 



103-8 



Diurnal Variation of the Mean Pressure of the Wind while blowing. — This is obtained by dividing the 

 sums of the pressures by the number of times which the wind blew, and is as follows : — 



SI" 10". 

 lb. 



1-01 



7>' 10". 

 lb. 



0-80 



9^ 10". 

 lb. 



0-83 



111" 10" A.M. 1^ 10" P.M. 



lb. 



0-91 



lb. 



0-88 



31= 10". 

 lb. 



0-79 



St 10". 

 lb. 



0-74 



7" 10". 

 lb. 



0-69 



gt 10". 



lb. 



0-82 



The wind, while blowing, was a minimum about 7** 40™ a.m. 



maximum at Noon. 



minimum about 7** 10™ p.m. 



The greatest force occurred at 5*" 10™ a.m. ; the maximum pressure of the wind while blowing probably 

 occurs, therefore, at or after midnight. 



The fact that the wind blows vdth the greatest force at Noon, but the greatest number of times at l*" 30™ 

 p.m., the time of the maximum temperature, explains why the sums of the pressures attain their maximum be- 

 tween these two periods. 



