SERIES D.— MONTHLY DEFLECTIONS. 



167 



SERIES J).— Continued. 



No. 135. — Madagascar (Tananarivou). 



Mean direction of 

 Wind. 



January 

 February 

 March . 



N. 62° 5' E. 

 S. 82 42 E. 

 N. 71 53 E. 



28 

 79 

 53 



By combining in succession the resultants for the several months at any place, 

 as given in the preceding series of tables, a general outline is obtained of the track 

 pursued by the wind in the course of a year. The results, at a considerable num- 

 ber of places, are exhibited in Plates VII., VIII., and X. Each of the twelve 

 parts, into which the curve is divided, shows the mean path of the wind in the 

 corresponding month, the curve commencing in all cases with January, and ending 

 with December. 



It is obvious that much more extensive data would be needed, to secure accuracy 

 in the form of the annual curve, than in the mean annual direction merely ; and 

 hence it was not thought worth while to exhibit in the plates any results based on 

 less than three years' observations, except in a few rare localities. The numbers 

 at the origin of the curves correspond with those in Series D, and may serve as 

 references. 



In order to render the form of the curves more distinct to the eye, they are 

 drawn on a scale four times larger than the arrows which represent the mean 

 annual directions, as may, in most cases, be seen by comparing the distance between 

 the two extremities of any curve with the straight arrow for the same place. A 

 few of the curves, however, are not computed from the same data as the mean 

 annual direction, one embracing a greater number of years than the other, which 

 produces slight discrepancies in the results. 



In some few instances, where the general form of the curve was obvious, and 

 where combining the results of two or three successive months would cancel irre- 

 gularities, it has been done, and the tracks for the separate months preserved by 

 means of dotted lines. As, for example, in the curve for Jerusalem (Plate VII. 

 No. 117), the tracks for the months of November and December are united. 



