444 



Dr A. Buchan. 



now arrived at by the various workers in meteorology, and of the 

 opinions and theories promulgated by different meteorologists in 

 different departments of the science. The book is largely used in 

 secondary schools and colleges of the United States, and the views 

 there stated are widely held in America and are spreading into other 

 countries. 



The following extracts from Davis's book fairly represent these 

 views : — 



" The surface winds of the temperate latitudes, and the high level 

 currents above them, sidling swiftly along on their steep poleward 

 gradients, must all be considered together. They combine to form a 

 vast aerial vortex or eddy around the pole. In the northern hemi- 

 sphere this great eddy is much interrupted by continental high 

 pressure in winter or low pressure in summer, and by obstruction 

 from mountain ranges, as well as by irregular disturbances of the 

 general circulation in the form of storms " (p. 110). 



Now the facts of observation do not support the theory of the 

 existence at any season of the year, of a low barometric pressure, or 

 an eddy of winds, round or in the neighbouring regions of the North 

 Pole. Observations show us no prevailing winds blowing home- 

 wards to the region of the North Pole at any time of the year. 

 No low barometric pressure occupies the immediate polar region in 

 any month ; but instead the opposite holds good for the four months 

 from April to July. In April and May the mean atmospheric pres- 

 sure is higher in the region of the Pole than it is anywhere in the 

 northern hemisphere north of 43° lat. N. ; and in June and J uly 

 also higher than it is anywhere north of 55° lat. N. Now the 

 higher pressure in these four months necessitates the existence of 

 upper currents in order to maintain this high pressure about the 

 North Pole. These upper currents towards the pole are exactly 

 opposed to the requirements of the theory that the upper currents 

 in the region of the Pole must necessarily blow not towards but 

 from the Pole. 



The actual centre, in this hemisphere, north of the tropic towards 

 which the winds on or near the surface of the earth blow, is not 

 the North Pole; but in the winter months the low barometric de- 

 pressions in the north of the Atlantic and Pacific respectively, and 

 in the summer months the low barometric depressions in the Eura- 

 sian and North American continents; and the sources out of which 

 the prevailing winds blow in the winter months, the high-pressure 

 regions in Siberia and North America ; and in the summer months 

 the high-pressure regions lying northward of these continents, 

 which, as already explained, are virtually the polar region itself. 

 These are the facts in all regions where the winds, according to 

 the theory, become winds blowing over the earth's surface. 



