430 SCIENTIFIC ADVANTAGES OF AN ANTARCTIC EXPEDITION. 



importance to note that averages of pressure and prevailing winds arb 

 published with the report — an accompaniment to the maps of mean 

 atmospheric pressure and prevailing winds of the globe not yet given 

 in any other series of maps of mean pressure and prevailing winds. 



This, then, is the work undertaken and published in these reports, 

 which occupied seven years in preparing, as time could be spared from 

 official duties. The result of the charting of the pressure and prevail- 

 ing winds is this : Stand with your back to the wind, then the center of 

 lowest pressure that causes the wind will be to the left in the Northern 

 Hemisphere and to the right hand in the Southern Hemisphere, a 

 relation well known as Buys Ballot's law. In charting the 1,366 jores- 

 sures and the relative prevailing winds, no exception was found in any 

 of the two hemispheres. This is one of the broadest generalizations 

 science can point to. 



Some years ago a theory of atmospheric circulation was published by 

 the late Professor Ferrel, which, as it is not accordant with the broad 

 results arrived at in the report of atmospheric circulation in the Chal- 

 lenger reports, calls for serious consideration on account of its bearing 

 on any attempt proposed to be undertaken for the exploration of the 

 Antarctic regions. 



One of the more recent expositors of this theory is Professor Davis,, 

 of Harvard College, who, in his Elementary Meteorology, gives an 

 admirable exposition of the results now arrived at by the various 

 workers iu 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 these views are all but universally held there, and 

 are now sj)reading over other countries. 



The following extract from Davis's book fairly represents these views 

 as generally entertained : 



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

 currents above them, sliding swiftly along on their steep ijoleward 

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

 vast aerial vortex or eddy around the pole. In the Northern Hemis- 

 phere this great eddy is much interrupted by continental high pressure 

 in winter or low pressure iu 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 exist- 

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

 eddy of winds, round or in the neighboring regions of the North Pole. 

 Observations do not show us any prevailing winds blowing homeward 

 to the North Pole at any time of the year. Further, no low barometric 

 pressure occupies the immediate polar region in any month; but, 

 instead, the opposite holds good for the four mouths from April to 

 July. In April and May the mean atmospheric pressure is higher in 

 the region of the pole than it is an;y where in the northern hemisphere 



