MADE AT BRUNSWICK, MAINE. 



39 



Where the letters S, S W, W, etc., represent the sum of all velocity numbers, 

 expressed in miles per hour, during the given period, or the quantity of air moved 

 in the directions S, SW, W, etc., respectively. E^ represents the total quantity of 

 air transported to the northward, and R^ the quantity transferred to the eastward. 

 These formulae for practical application may be used under the following form: — 

 Let S—N^a SW—NE^G 



W—E =z b NW—SE ■= d 



Then • , • 



R,=Rcos^ = a+ 0.707 {c—d) 



R^=R sin ^ = & + 0.707 (c-^d) 

 Since R^, R^, R, represent the quantity of air passed over during the given 

 period in the direction 0° 90° 4-° respectively, we must, in order to find the average 

 velocity for any resulting direction, divide by 7i, or by the number of observations 

 during that period; we have consequently: — 



R, 



R„ 



and V=— 



" ?^ n n 



A particle of air which has left the place of observation at the commencement of 



the period, of a day for instance, will be found at its close in a direction 180° + 4-, 



R 

 and at a distance of R miles, equal to a movement with an average velocity of — _ 



this supposes an equal and parallel motion of all particles passing over ; the length 

 of the path described by each can be found by summation of all the v's during the 

 period. 



In the present case the above formulae become simplified for want of recorded 

 velocities which may .all be put equal unity, consequently the summations wiU give 

 at once the relative frequency with which each wind occurred during a given period. 



Owing to the great variability in the observed directions of the wind, periods less 

 than a month are not suitable for combination. 



The following Table X contains 54,09.7 observations arranged for each month 

 according to eis^ht directions. 



Table X. — Relative Frequency of each Wind recorded during 50^ Years, three 



TIMES A DAY. 



■ 



S. 



N. 



W. 



E. 



s. w. 



N. E. 



N. W. 



S. E. 



No. of years. 



January . 

 February . 

 March 

 April 

 May . 

 June 

 July . 

 August 

 September 

 October 

 November 

 December . 







42 



63 



109 



160 



206 



194 



236 



166 



138 



147 



67 



39 



253 

 214 

 194 

 183 

 149 

 141 

 136 

 136 

 136 

 177 

 229 

 250 



254 

 247 

 221 

 185 

 116 

 163 

 251 

 246 

 193 

 275 

 297 

 301 



91 

 92 

 153 

 171 

 268 

 149 

 111 

 110 

 116 

 106 

 113 

 83 



912 



930 

 1188 

 1312 

 1619 

 1797 

 2154 

 2049 

 1645 

 1351 

 931 

 921 



1071 

 817 

 646 

 645 

 565 

 395 

 297 

 352 

 448 

 575 

 813 



1107 



1717 

 1646 

 1768 

 1409 

 1064 

 1118 

 1127 

 1139 

 1260 

 1484 

 1821 

 1782 



161 

 178 

 372 

 447 

 620 

 533 

 378 

 437 

 297 

 337 

 249 

 136 



50 

 51 

 51 

 51 

 51 

 51 

 51 

 51 

 48 

 49 

 51 

 51 



Year. 



1567 



2198 



2749 



1563 



16809 



7731 



17335 



4145 





Proportional number 

 in 1000 winds 



29 



40 



51 



29 



311 



143 



320 



77 





