THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 



295 



Hence of all seasous of the year winds from N., E., and N.E. have a pressure above 

 the mean, and those from W. and S.W. below it. Barometric pressure with W. and 

 S.W. winds falls below the mean to a greater extent in Spring than at any other season, 

 while in Summer the excess of pressure with N. winds is more than three times greater 

 than in Winter, which for the wind in question has the next greatest excess. 



The mean temperature experienced with different winds is shown in the following 

 table : — 



On the mean of the year the warmest wind is N., with an average temperature of 

 43°'9, and the coldest S., with a mean of 40°, the range being only 3°"9. At all seasons 

 the conserving influence of the surrounding ocean is shown in the small difference 

 between the coldest and warmest winds. Except in winter the N. is the warmest 

 wind, but the direction from which the lowest temper-ature is experienced varies, being 

 S. in Spring and Autumn, S.E. in Summer, and W. in W'^inter. 



The divergence from the mean is shown iu the foUowino- table : — 



Hence it will be seen that the effect of the warmest — viz. the N. — wind is to raise 

 the temperature only 1°'3, while the coldest wind S. depresses it as much as 2^'6,the 

 amount being greatest 4°"2 in Autumn and least I°"7 in Winter. In Summer, W. and 

 N.E. winds respectively have practically the mean temperature of the season, but 

 in "Winter the former is 3° below the average, while the latter is 2°7 above it. It is 

 ])robable that the comparative higli temperature experienced with W. winds in 

 Summer is due to the heating of the land mass of the Falklands lying in thiit direction, 

 while in Winter the chilling effects of radiation strongly influence air currents from the 

 W. Strictly oceanic winds, probably at all seasons of the year, have a temperature 

 closely approximating to that of the sea surface over which they have blown before 

 reaching the point of observation. 



VOL. II. 40 



