Peessure and Dieection of. the Wind. 



XCIX 



These numbers still present several irregularities ; on the whole, however, the wind blows with the greatest 

 force about l^ p.m., and with the least force about 'J^ p.m., or about an hour after noon and an hour after sunset 

 respectively; another minimum of force occurs at 7'' a.m., an hour after sunrise, and a secondary maximum 

 occurs between 11^ p.m. and 5"^ a.m., the exact epoch is not deducible ft-om these means ; the means for 1844 

 and 1845 only, place it near midnight. 



207. Yearly Mean Value and Direction of the Resultant Wind. — From the last line of Table 95, it appears 

 that the direction of the resultant wind was nearly constant in each of the three years, 1843, 1844, and 1845. — 

 1846 appears to have been quite anomalous ; in each of the former years there are eight or nine months in 

 which the resultant wind blows from between west and south, for only two or three of these months is the 

 resultant nearer south than west ; biit in 1846 there are ten months, for which the resultant wind blows from 

 between south and west, and for eight of these it is nearer south than west. 



If we neglect the year 1846, the winds atMakerstoun are equivalent to one continuous wind blowing from 

 nearly WSW. with a force approximately of about two-tenths of a pound on a square foot of surface. 



Table 95. — Values and Directions of the Resultant Winds, with the Sums of the Pressures of the 

 Wind resolved into the four Cardinal Points of the Compass, for each Month of the Years 1843-6. 



Month. 



1843. 



1844. 



1845. 



1846. 



1843-6. 



1843-6. 



Resultant. 



Resultant. 



Resultant. 



Resultant. 



Sums of Pressures ob- 

 served at the 24 Obser- 

 vation Hours for 100 

 Days in each Month, 

 resolved into 



Resultant. 



Mean. 



Direction. 



Mean. 



Direction. 



Mean. 



Direction. 



Mean. 



Direction. 



N. 



E. 



S. 



w. 



Mean. 



Direction. 



Jan. 



lb. 



0-9.3 



W. 



17 S. 



Vo. 



0-27 



w. as. 



lb. 

 0-36 



s. 



29 W. 



lb. 



0-37 



s. 



43 W. 



lb. 



172 



lb. 



45 



lb. 



700 



lb. 



933 



lb. 

 0-43 



W. 29-5 S. 



Feb. 



0-43 



N. 



8 W. 



014 



W. 37 K 



0-22 



w. 



9S. 



0-38 



w. 



34 S. 



534 



161 



408 



565 



0-18 



W. 17-3 N. 



Mar. 



004 



S. 



31 E, 



0-20 



W. 5 N. 



0-39 



w. 



2 S. 



0-52 



s. 



38 W. 



332 



153 



580 



667 



0-24 



W. 26-3 S. 



April 



0-26 



w. 



23 S. 



0-35 



W. 32 S. 



0-15 



N. 



7E. 



0-21 



N. 



24 E. 



423 



174 



406 



423 



0-10 



W. 3-9 N. 



May- 



0-20 



E. 



4 N. 



0-16 



N. 24 E. 



0-28 



N. 



11 E. 



0-32 



s. 



44 W. 



446 



377 



313 



317 



0-06 



N. 24-2 E. 



June 



0-12 



N. 



4E. 



0-34 



W. 30 S. 



0-34 



S. 



44 W. 



0-30 



s. 



39 W. 



223 



133 



540 



549 



0-22 



W. 37-4 S. 



July 



0-29 



W. 



37 S. 



0-06 



W. 4N. 



013 



w. 



43 S. 



0-38 



s. 



44 W. 



140 



88 



445 



451 



0-20 



W. 40-0 S. 



Aug. 



0-18 



s. 



26 W. 



0-18 



W. 15 S. 



016 



w. 



29 N. 



0-07 



s. 



30 W. 



186 



79 



292 



332 



0-11 



W. 22-7 S. 



Sept. 



0-06 



w. 



24 N. 



0-07 



W. 33 S. 



0-15 



w. 



29 S. 



0-05 



s. 



34 W. 



161 



111 



238 



267 



0-07 



Vf. 26-1 S. 



Oct. 



019 



w. 



1 S. 



0-23 



S. 43 W. 



0-45 



w. 



34 S. 



0-08 



w. 



35 S. 



249 



156 



543 



613 



0-23 



W. 32-8 S. 



Nov. 



0-33 



w. 



24 S. 



0-14 



S. 23 E. 



0-44 



s. 



32 W. 



0-28 



s. 



15 W. 



176 



192 



705 



505 



0-26 



S. 30-7 W. 



Dec. 



0-69 



w. 



40 S. 



0-06 



E. 30 S. 



0-69 



w. 



16 S. 



0-24 



N. 



40 W. 



262 



42 



546 



790 



1 



0-33 



W. 20-8 S. 



Year 



0-20 



w. 



21 S. 



0-13 



W. 21 S. 



0-23 



w. 



23 S. 



0-19 



w. 



41 S. 



274 



143 



477 



535 



0-18 



W. 27-3 S. 



208. Annual Variation of the Force and Direction of the Resultant Winds. — The details of these discus- 

 sions will be found in pages 64 and 84 of this volume, p. 295, 1843, and p. 434, 1844. From Table 95, it 

 appears that — 



\st, The sums of pressures of the northerly winds are greatest in the months of February, March, April, 

 and May ; they are least in the months of July, August, September, and November. 



2c?, The sums of pressures of the easterly winds are tmce a maximum and twice a minimum in the year; 

 they are a principal maximum in May, and a secondary maximum in November ; they are a minimum in July 

 and August, and in December and January. 



3d, The sums of pressures of the southerly winds are greatest in November and January, and they are 

 least in September. 



4:th, The sums of pressures of the westerly winds are greatest in December and January, and they are least 

 in September. 



bth, When We examine the approximate mean forces of the resultant wind for each month, we find that on 

 the whole they exhibit two maxima and two minima in the course of the year. The resultant wind is a principal 

 maximum in January, and a secondary maximum in June and July ; it is a minimum in May and in September. 



Qth, The direction of the resultant wind is from 17° north of west in February, from 4° north of west in 

 April, from 24° east of north in May, and from between west and south in the remaining nine months of the year. 



MAG. AND MET. OBS. 1845 AND 1846. 2 h 



II 



