AN ESSAY ON SOUTHERLY BURSTERS. 161 



accordingly. When the wind is light these storms are often 

 carried to sea by the general easterly motion of the atmosphere, 

 and may be seen passing by, the peculiar clouds indicating unmis- 

 takably their position." 



APPARENT DOUBLE BURSTERS. 



The following is a detailed account of a double burster, or of 

 two distinct simultaneous bursts on different parts of the coast. 

 It will be convenient to commence with a table, showing the 

 hours at which the burst reached various points on the coast-line, 

 with relative rates of travel from place to place : — 

 10th October, 1893. 



Stations, 



Eden ... 

 Moruya 

 Jervis Bay 

 Wollongong 

 Sydney- 

 Newcastle 



Rate of Travel. 



Distances. Hour. Interval. Miles 



— 2 a.m. — — g 



79 8-30 6 30 12-2 <s ft 



47 10*36 2 6 22-4 £>J 



41 11-45 1 9 32-8 .§'§ ^ 



41 1 p.m. 1 15 328 % «5 g 



. 62 3-40 2 40 233 > " A 



Mean rate of travel 25*3 

 Port Macquarie... 110 2 p.m. 





Clarence 122 5"30 3 30 34*9 ^ £ 



From this table it will be seen that the wind changed to south 

 at Eden, the southern point of the coast at 2 a.m., and made its 

 way gradually up the coast, reaching Sydney at 1 p.m. and New- 

 castle at 3 # 40 p.m. in the mean time that is at 2 p.m. Port 

 Macquarie, one hundred and ten miles north of Newcastle, reports 

 the change at 2 p.m., or one hour and forty minutes before it got 

 to Newcastle, or to put it another way, when one burster reached 

 a point on the coast twenty miles north of Sydney, another made 

 itself felt at Port Macquarie, one hundred and ten miles farther 

 north, it appears then that there were two bursters separated by 

 one hundred and ninety miles and simultaneously making their 

 way along the coast. It is probable, however, that the southerly 

 burster is a line storm, and that the change of wind occurs along 

 a certain isobar, and if this be the true explanation it is entirely 

 in accordance with what has already (page 151) been shown as to 

 the trend of the isobars in certain cases. When the approaching 

 anti-cyclone flattens its isobars against our dividing range, and. 



K— July 4, 1894. 



