BY THE REV. W. B. CLARKE, M.A., F.G.S., &c., V.R 173 



conditions consequent on the passage of the eastward edge of the 

 gale. 



Similarly, if gales come in from the N".E., unless they are verti- 

 cally thick enough, they also travel southwardly along the eastern 

 slopes of the Cordillera, and never water the western interior. 



I have collected examples of numerous gales which, although 

 violent along the coast and up to the slope of the mountains, 

 deluging the sea board with rain, have only been recognised at 

 Bathurst or Wellington by a slight shower or Scotch mist, or a 

 gently disturbed atmosphere. Such was the case during some 

 of our late tempestuous weather ; for, whilst the Coast was under 

 floods, patches of the western country were suffering from drought, 

 being cut off by the high lands from access of the easterly winds. 



Mr. Tebbutt's mention of scud at Windsor when there is a 

 storm at Sydney, and of only rare westerly gales at the former 

 place, is thus to be explained. The scud beiag probably only 

 evaporated moisture is borne on the very top of a thin gale ; and 

 he, no doubt, rightly admits such local influences from the coasts 

 and mountains. 



Mr. Tebbutt quotes the case of the storm of 25th and 26th 

 October, 1863, showing that the same changes of wind and 

 barometrical oscillations occurred between Adelaide and Windsor 

 at an interval of 26 hours, and about a day later at Brisbane. 



Now, these successive changes prove that that gale was a Cy- 

 clone, having probably a diameter of about 250 miles, and a mean 

 progress of about 24 miles per hour (which is in remarkable 

 agreement with the rate of numerous great East Pacific storms 

 and cyclones), the eastern edge of which grazed and came over 

 the summit of the Cordillera where it was about 4000 feet above 

 the sea ; the thickness of the storm being about 5000 feet, which 

 is the height, as obtained by measurement by myself, of very many 

 of the gales in this colony. Mr. Redfield and Mr. Piddington 

 assume a thickness of a mile (280 feet more) for several known 

 cyclones. 



On the east coast the gales appear to me to be at certain 

 seasons of an equally cyclonic character. And Mr. Tebbutt quite 

 co-incides in opinion with me as to the nature of those gales, 

 as resulting from the combined forces of polar aerial currents and 



M 



