The Rev. T. E. Robinson's Description of an improved Anemometer. 177 



Data 



March 29, 10 p.m. 

 11 

 12 



1 A. M. 



2 

 3 

 4 

 5 

 6 

 7 

 8 

 9 

 10 



Space. 



33" -5 

 320 

 311 

 29-4 

 30-3 

 31-5 

 30-5 

 31 1 

 3M 

 32-9 

 33-6 

 37-5 



Directioa 



303° -8 

 313-8 

 320-5 

 307-3 

 314 

 294-7 

 77-2* 

 78-8 

 66-7 

 69-1 

 88-2 

 88-2 

 99-9 



w. 



-26'"-l 



-21-8 



-22-4 



-22-3 



-25-0 



-19-9 



+ 29-9 



+ 29-7 



+ 28-8 



+ 24-5 



+ 33-4 



+ 37-5 



+ 21'' -0 

 + 23-4 

 + 21-5 

 + 19-1 

 + 17-1 

 -24-4 

 + 6-3 

 + 9-3 

 + 11-7 

 -220 

 + 1-0 

 - 0-3 



Sum, 



385-5 



+ 46-3 + 83-7 



1 



The means for the two irregular houz-s are taken from the reading for 

 each tenth. We have tan D = g|, which, as both are positive, must be in 

 first quadrant, therefore, 



D.= 28?-95, and 2 = -^ 



46-3 



sin 28°-57' ~ ^^■^^■ 

 It appears therefore, that during these twelve hours, the real movement of 

 the air was only 956 miles, from a point 29° west of south. 



For all purposes of physical investigation, this method of exhibiting the 

 results IS fully efficient ; at the same time it is much to be desired, that some 

 graphic method could be devised which would exhibit to the eye the relation 



• At 3" -30" the wind veered suddenly 217° -5, against the order of graduation, which is shown 

 by the sign _. The mean direction for the hour = 219° -2. There also was at r exactly another 

 Teer, in the same direction, of 210° -5. The mean direction for the hour = 13-^° -0 



