320 Meteorological Observations at Hudson, Ohio. 



arbitrary scale, explained in this Journal, vol. xxxvi, p. 173, may 

 possess some interest. The mean of the extreme excursions of 

 the vane during an interval of five minutes, I call its true direc- 

 tion ; and the force I regard as the distance. This is resolved 

 in the direction of the four cardinal points by the usual method. 

 Each observation is resolved separately, and the sum of the north- 

 ings and southings, eastings and westings, for a month, furnishes 

 its mean direction. The following table exhibits the sum of 

 these quantities for the corresponding months of the three years. 



Sum of 9 A.M. and 3 p. m. ] 1297.50 ] 1088.07 | 642.53 | 2387.87 



Course. 



N. 8309'W. 



It appears then that during a period of three years, the pro- 

 gress of the wind in spring and summer has been at 9 A. M. 

 from north to south, in autumn and winter from south to north, 

 the latter motion being slightly in excess so as to produce a re- 

 sulting motion from the south. At 3 P. M. the wind's progress 

 has been from the north during nine months of the year, and 

 this excess of northerly winds has been such, that taking the 

 sum of observations at both hours, the absolute progress has 

 been from a point seven degrees north of west. Dividing this 

 absolute progress from north to south by the whole number of 

 observations, we obtain .0991 for the mean motion in this direc- 

 tion corresponding to each observation. The mean force of the 

 wind has been 2.04, making the actual progress of the wind 

 from north to south about five per cent, of the total motion ; and 

 if we assume with Mr. Redfield (Am. Jour. vol. xxv, p. 125) 

 the average velocity of the wind at eighteen miles an hour, we 

 arrive at the following important conclusion, that at this place 

 the absolute progress of the vjind, in the direction of the mei'id- 

 ian, is from north to south at the rate of seven eighths of a mile 

 per hour. 



