AN ESSAY ON SOUTHEKLY BURSTERS. 155 



PARTIAL TO COAST OF NEW SOUTH WALES. 



Not only during the summer, but in all seasons of the year, the 

 southerly has a remarkable partiality for the sea-board of New 

 South Wales. 



OVER STEP ISOBARS. 



So much is this the case in the hot months that the approaching 

 currents from the south have been observed on the coast when the 

 isobars indicated northerly winds. 



BLOW CONTRARY TO ISOBARS. 



Sometimes, too, for several consecutive days, the wind has blown 

 with appreciable velocity from this quarter when the isobaric 

 lines — from their relation to the centre of the anti-cyclone — should 

 be producing northerly winds. This latter peculiarity is most 

 noticeable in winter months and with necessarily small gradients. 



THE AREA OVER WHICH THE BURSTER EXTENDS. 



The land area over which the burster exercises its influence may 

 be generally described as including all the country east of the 

 mountains in New South Wales, from the extreme south-east 

 point of the colony to a little above Port Macquarie on the north 

 coast. It occasionally oversteps this northern limit, but when it 

 does so it is usually the result of a cyclonic disturbance on the 

 north coast, such as existed, for example, in the " Dandenong " 

 burster, the effects of which were felt considerably north of 

 Brisbane. The northern boundary of the burster may be defined, 

 as limited by the south-east trade winds, which blow almost 

 incessantly north from about 30° S. latitude. Other areas of 

 actual experiences are given on page 145. 



CHANGE OF TEMPERATURE. 



Bursters always result in a diurnal drop in temperature, the 

 said drop ranging between 37*5° and 4*2° with an average fall of 

 18'1°. The greatest diminution of temperature takes place during 

 the first hour, and the fall is most sudden when the burst comes 

 at midday. The steepest drop on record was that registered at 

 1*50 p.m. on the 30th December, 1891. The maximum then read 

 97*5° ; five minutes after the change to south it read 80*3°, being 



