THEORETICAL EFFECTS OF PRESSURE WAVES. 



229 



(a) (6) 



Fig. 73. Moditied pleasure distribution. = 360°. 



e = 360°, figure 73. — The high pressure is still over the Barrier and just to the south 

 of Cape Evans where the wind must still be southerlj^ In fact, southerly winds exist over 

 the whole area. The area of high pressure is steadily movijig northwards and in a short 

 time after this epoch it passes over Cape Evans when there is a sudden reversal of the 

 wind from the south to the north. The blizzard is over and a northerly wind sets in. The 

 whole series then repeats itself as the next wave comes along. 



