158 ON AUSTRALIAN STORMS, 



Observatory and South Head, it will be seen that tropical winds 

 prevailed throughout the 14th, 15th, and 16th. The prevalence 

 of these winds was made manifest by a falling barometer, and 

 rising thermometer. The lowest recorded reading of the former 

 instrument occurred at three p.m. on the 16fch, being 29.587, 

 differing only O064 from the minimum at Adelaide. These 

 values are at once comparable, because the heights of the Sydney 

 and Adelaide Observatories above the sea are nearly equal. During 

 the night of the 16th the polar winds were first felt at Sydney, 

 blowing strong from the west during the forenoon of the 17th, 

 the barometer rising and the thermometer falling. On referring 

 to the account of the gale at Adelaide, it will be seen that the 

 least pressure of the atmosphere and the reversal of the wind 

 occurred there many hours earlier. And probably if the wind 

 observations at Brisbane were before us, we should find that the 

 polar winds were not experienced there till the 18th, that is, if 

 the storm had not expended itself before reaching so far north. 

 However, we perceive from the diagrams that the least pressure 

 occurred on the 17th, or one day later than at Sydney. On the 

 whole, it would appear, that the barometric oscillations decrease 

 as we advance towards the tropics. An inspection of the curves 

 contained in Mr. Scott's Volume of observations for 1861, will 

 make this circumstance at once apparent. 



It is unnecessary for me to go into a consideration of the 

 other period of great atmospheric disturbance, which characterized 

 the year 1861. Those who wish to go further into the subject, 

 may profitably examine the following storm periods : May 

 21st 24th. June 15th 26th. During the latter period the 

 barometer remained low for several days, owing to the re- 

 markable persistency of the tropical winds. There is one thing 

 that cannot have escaped the observation of those who have 

 studied the winds, that their effects are different in different 

 places owing to local influences, such as coasts and mountains. 

 On comparing my own observations with those made at the 

 Sydney Observatory, I find that all winds blowing from the 

 eastern semi-circle between north and south, are felt with much 

 more effect at Sydney than at Windsor. This circumstance, I 

 have no doubt, is owing to the winds from the sea being deflected 



