RECORD AND DISCUSSION OF FORCE OF WIND. 



81 



The greatest quantity of air moved over the place during the year comes from 

 a quarter bounded by the true directions S. E. by E. and N. N. E.; the prevailing 

 wind also comes from this quarter. With the exception of true S. W. by S. winds, 

 there is comparatively hardly any wind from the remaining directions; the quad- 

 rant between (true) west and north is particularly defective in this respect. 



The calms greatly predominate, there being during the year more hours of calm 

 (5063) than hours of wind from any direction (3697)— a circumstance quite cha- 

 racteristic of the locality. 



Average Duration of the Winds.— 1\\e number of consecutive hours during which 

 any one wind blew is given in the table below. It contains average values made 

 out from all observations during the seventeen months. The number of consecu- 

 tive hours during which, on the average, calms lasted, is likewise given. 



Magnetic direction. 



s. . 

 s.w. 

 w. . 



N.W. 



N. . 



Mean duration. 



. 2''-.8 



. 3.4 



. 2.0 



. 3.4 



. 2.t 



Magnetic direction. 



N. E. 

 E. . 

 S. E. 



Mean duration. 



. 2'M 

 . 2.1 

 . 3.3 



Calm 



T.8 



Rotation of TFt'nfZs.— Owing to the great number of calms, and partly, also, to 

 the generally small quantity and velocity of the winds between the (true) S. and 

 (true) N. W. directions. Dove's laws of rotation cannot well be verified in this 

 locality. There is, however, a tendency of the magnetic S., S. E., and E. (E. N. E., 

 N. N. E., and N. N. W., true) winds to shift, in accordance with the law, in the 

 proportion of three cases for to one case against it, or with a relative probability 

 of three-fourths in favor of the law. 



Note on the Occurrence of feZes.— Between September 1st, 1853, and January 

 24th, 1855, there were recorded thirteen gales (with a force of 7 and above, and a 

 duration of not less than two hours). The date, direction, and duration of these 

 gales is shown in the following table. 



1858 



1854 



Date. 



Dec. 10 

 Dec. 28 

 Feb. 7 

 Feb. 15-16 

 April 15-16 

 June 11 

 July 28 



General (mag.) 

 direction. 



S. E. 

 S. E. 

 S. E. 



S. 



s. w. 

 s.w. 

 s.w. 



Duration. 



2li- 

 22 



3 

 4 



1 

 3 

 G 



1854 



1855 



Date. 



Sept. 30 

 Oct. 15 

 Nov. 20 

 Dec. 18 

 Jan. 13 

 Jan. 18-19 



General (mag.) 

 direction. 



S.W. 



S. E. 

 S.W. 



S. E. 

 S. E. 

 S. w. 



Duration. 



10"- 



3 

 10 



5 



3 



4 



These gales do not appear to be confined to any particular season of the year. 

 On the average they last seven hours, and in summer they have a tendency to 

 blow from the S. W. (true E. S. E.), and in winter from the S. E. (true N. N. E.). 

 These two directions are the only ones from which gales were observed. 



Thermometric and Barometric Wind Rose.-Th^ investigation of the connection 

 of the temperature and weight of the atmosphere with the direction of the wmd, 

 will be found in the discussion of the observations for temperature and barometric 

 pressure, parts I and III of this paper. 

 11 



