10 AVINDS OF THE NORTHERN HEMISPHERE. 



Series A, contains a list of the stations, or places of observation, with their 

 latitudes and longitudes from Greenwich, and the names of the observers as far as 

 known. ^ 



Series B, contains abstracts of the observations on the direction of the wind at 

 the different stations. With a view to greater condensation, months of the same 

 name in difierent years are often united, so as to make but a single table of monthly 

 abstracts, even though the observations extend through a number of years. The 

 wind-roses, in the Plate of this series, exhibit to the eye the relative predominance 

 of the different winds, the width of the shading at the different points of compass 

 being proportional to the time during which the winds prevailed from those points. 



Series C, shows the mean direction and rate of progress of the wind at the dif- 

 ferent stations, computed in the manner already described, from the data contained 

 in series B. Besides the general results for the whole time, there is given also, at 

 a tew places, the separate results for each year. I undertook, at first, to do the 

 same for all the stations, but the labor was so great that it became questionable 

 whether the results would be worth the cost, and the idea was relinquished. Ac- 

 companying the tabular statements is a series of maps, on which the mean direction 

 and rate of progress of the wind at the different stations is exhibited to the eye by 

 means of straight arrows. The length of the arrow, exclusive of the point, shows 

 the ratio of the progressive motion of the wind to the whole distance traveller!, 

 the unit being one inch. That is to say, if the wind were to blow uniformly in 

 one direction, it would be represented by an arrow one inch long; if the pro- 

 gressive motion were fifty miles, for every hundred miles travelled, the length of 

 the arrow would be half an inch, and so on. 



Series D, shows the deflections of the wind from its mean annual course in the 

 different months of the jear, together with the direction and amount of the forces 

 which jDroduce these deflections. For a more full description of the process em- 

 ployed, the reader is referred to the Introduction to this series. The tabular 

 statements are illustrated by two series of plates, one showing the monthly direc- 

 tion of the wind, and the other the deflecting forces. The former are shown by 

 means of curves, divided into 12 parts, each part showing the mean path of the 

 wind for one month, and, consequently, the whole the annual curve. The latter 

 are represented by means of arrows, twelve for each station, corresponding to the 

 months of the year. The direction and length of the arrow for any given month 

 shows the direction and amount of the deflecting force in that month, the scale 

 being the same as in the plates following Series C. 



Series E, shows the average relative force, or velocity, or both, of winds from the 

 several points of compass, and is accompanied by wind-roses exhibiting the same 

 facts to the eye, the width of the shading at each point of compass being propor- 

 tional to the average velocity of the wind at that point. 



' When tLis investigation was first undertaken, the author had no idea of ever publishing the results, 

 and proper care was not taken to preserve the name of the person by whom, or under whose direction, the 

 observations were taken, so that in many cases, particularly on the Eastern Continent, I am not able now 

 to give appropriate credit. 



