AN ESSAY ON SOUTHERLY BURSTERS. 163 



Queensland inland stations, In Sydney, for three days previous 

 to the arrival of the burster, the sky was hazy and almost tropical 

 in its aspect. The barometer at Sydney fell three-tenths during 

 the twenty-four hours immediately preceding the burst, and rose 

 rather sharply after it had passed, the lowest point making half- 

 an-inch in twenty-four hours. The temperature was moderate 

 immediately before the change, the thermometer stood at 75°, and 

 at 2 p.m., rather less than one hour after, it had fallen to 65°* 

 A roll of cumulus cloud of a rather undefined character was first 

 seen at 12*30 p.m., with a line of ragged cirrus beneath. The 

 latter, as the storm advanced, rose in front of and obscured the 

 cumulus. Five minutes later, cirrus were moving horizontally, 

 vertically, and in every other direction from a point in the cloud 

 lying due south. The change of wind at Sydney came at 1 p.m., 

 and was attended by much dust, and some rain which was entirely 

 owing to electrical influences, it was generally light from the 

 western slopes to the coast. 



Passing from this record of the double burster, it is now neces- 

 sary to consider various facts relating to the time taken by 

 bursters in travelling along the coast. 



RATE OF TRANSLATION OF BURSTERS. 



From the preceding remarks and the figures quoted in the table 

 page 161, as well as other figures appended to page 164, it will appear 

 that no definite relation can be traced between the rate of trans- 

 lation and velocity of the wind in bursters. As already demon- 

 strated, it is quite possible for two bursts to occur on different 

 jparts of the coast at the same time, and it is also possible for a 



BURST SIMULTANEOUS OVER A WIDE AREA. 



burst to be felt at the same moment over an extensive area. (See 

 table 28th November, page 165. Since there is no visible con- 

 nection between the velocity of the wind and the ratio of transla- 

 tion of the burst itself, it may throw light on the matter if we 

 look for some explanation of the fact that the southerly change is 

 generally first experienced on the south coast of the Colony. 



