Edwin. — Meteorology of New Zealand. 



561 



movement of an anticyclone, followed by a cyclone from a 

 north-westerly direction. Each vertical space represents one 

 day. Each oval shows a decrease of two-tenths pressure 

 toward the central one. The small arrows indicate the wind- 

 rotation ; the long feathered arrow on the left shows that the 

 cyclone is travelling towards south-east, and the one on the 

 right that the anticyclone is progressing eastwards. The left- 

 hand side or rear part of the high pressure is shown slightly 

 indented as the effect of the approaching cyclone, whose front 

 curves are compacted in the line of its advance. 



Cyclone and Anticyclone (Southern Hemisphere). 



Using three positions — viz., a, b, and c — situated upon a 

 line from north-east to south-west, the diagram shows that 

 the movement of the high pressure to the eastward has caused 

 a decrease of pressure accompanied by northerly winds at 

 each station, and that as the cyclone approaches pressure 

 continues to decrease, and has at a fallen to 2990, wind 

 about north-north-east ; at b to 29 - 85, wind north-north-east ; 

 and at c to 29-90, wind north-east. The continued advance 

 of the cyclone causes further changes ; at a the decrease is to 

 29-60, wind north-west ; at c the wind has changed from 

 north-east through east to south-east, and pressure has 

 fallen to 29 - 40. The minimum pressure of the cyclone is 

 now at its nearest to both of these positions, but at b, which 

 lies directly in the track of the cyclone centre, pressure 

 has fallen rapidly to 29-05, and the wind, which remained 

 at about north-east, varies rapidly from all directions while 

 the centre is passing over b, finally steadying in the south- 



36— Trans. 



