t^all of Bain and Snov) at Wallingford^ Conn. 259 



The mean of the maxima for the year is nearly one-half greater at 

 Philadelphia than at Wallingford ; and the mean of the minima is 

 more tlian double. The ratio of the maxima to the minima is nearly 

 one-half greater at Wallingford than at Philadelphia. 



Mean direction of the Wind's progress. 

 In considering the circulation of the atmosphere for the entire globe, 

 it is important to know for each place, the average direction of the 

 wind's progress., and this is not necessarily the same as the average 

 direction of the wind, for its progress depends upon velocity as well 

 as direction. If we could construct a polygon, all of whose sides but 

 one shoiild represent the successive directions of the wind for any 

 assumed time, and the lengths of those sides should be proportional 

 to the wind's force in these several directions, the remaining side ol 

 the polygon would represent the direction and amount of the wind's 

 progress for that time. In order to reduce the Wallhigford observa- 

 tions upon this principle, the angles given in Table II, Part 1, were 

 regarded as the directions of a ship's course, and the numbers repre- 

 senting the wind's force for the given hour and month, as show^n in 

 Table YIIl, were regarded as the distances sailed. For these courses 

 and distances, the Northings and Southings, Eastings and Westings 

 for each hour were taken from a traverse table, and the total difference 

 of latitude and departure for each month were computed. Tlie result- 

 ing course was thence deduced by the j^rinciples of Trigonometry. 

 The following table shows the results of this computation. 



Table X. — Mean direction of the Wind^s progress. 



The mean direction of the wind's progress for the entire year is 

 from a point N. o5°-8 W., being 4°-l more southerly than the direction 

 obtained without regarding the wind's force. The difference arises 

 from the fact that the wind's force is generally greatest at that hour 

 of the day when its direction is most southerly. 



Fall of Raix and Snow at W^allixgford, Conn., 1856-1870. 



The observations on the fall of rain and snow began April, 1856, 

 and continued to August, 1862. They were resumed in November, 

 1864, and are continuous to the close of 1870. The rain-gauge em- 



