274 



Winds of the Globe. 



sion of his earlier treatise on the Winds of the Northern Hemi- 

 sphere. Its design is to show 



\f ™ e mean direction of the wind in all parts of the earth. - 

 Zd. J he ratio that the progressive motion bears to the total 

 distance traveled. 



^ 3 j*- £ ? he modifica tions that the mean current undergoes in 

 the different seasons of the year. 



4th. The directions in which the forces act that produce 

 these modifications. 

 5th. The amount of their intensities. 



6th. To show, by separate solutions for the surface winds 

 and those indicated by the motion of the clouds, how the two 

 (Jitter, and how they differ according as we do, or do not, take 

 into account the difference in the velocity of the different winds. 

 I he data used for elucidating these points consist of series 

 ol observations on winds made at 3,223 different stations on 

 iand and during numerous voyages at sea, extending from the 

 para lei of 83° 16' north latitude, to beyond the parallel of 75° 

 south latitude, the extreme points ever reached by man, altogether 

 embracing an aggregate period of over 18,500 years. If the area 

 between latitude 60° N. and 60° S., where observations are more 

 abundant, be divided into geographical squares, by drawing 

 meridians and parallels of latitude 5° apart, of the 1728 squares 

 so tormed 1410 are represented in this work. The 318 vacant 

 squares, from which no observations have been obtained, are as 

 toJlows: Twenty-one in North America, mostly in British Amer- 

 ica; torty in the interior of South America ; none in Europe; 

 seventy m Central Asia ; sixty-three in Africa ; fifteen in the 

 p T' Austr alia; one hundred and eight in the North 

 1-acinc Ocean; and one in the South Pacific Ocean. ' 

 ^;J e ?> mS ^ em ^ nentlj desirabl e that the great paucity in the 

 ™I? rw fi( l 0cean ' sbould be filled ; particularly as it is sup- 

 posed that the material for doing so exists, though entirely 

 unreduced, among the archives of the United States Naval 

 -department 



r P n^t f T i r tate 1 CODdensation in the results > the stations that 

 2S - dl f reCtl -7 t0 the Smithsonian Institution have been 

 grouped into convenient districts, about 100 miles square, and 

 ine total number of observations has been given for at least 

 Tn tL P °l the com P ass , during each of the four seasons. 



serifS p^TV^ T St ° ther Stations ' and Particularly when the 

 hP !fnr i through a lon S P eriod of years, the total num- 

 ber of observations is given for each month of the year, and 

 >mts of the compass. By this summary the dis- 



tinctive feat^of' the ^sZTof ZLin 72,' 



i of the 

 whpn 7r " uu , ,JUllier atea by condensation, excepting of course, 

 when those of a particular epoch are sought, i 



