160 ON AUSTRALIAN STOBMS, 



eight years will show that the mean force is greater at 3 p.m. 

 than at 9 a.m. or 9 p.m. The least pressure of the atmosphere 

 and the greatest activity in air currents occurring at the same 

 time as the highest temperature would seem to point to the 

 conclusion that the sun is the primary and chief agent in the 

 production of all our atmospheric commotions. 



One of the most interesting examples I have met with of the 

 propagation of storm phenomena over the colonies, was on the 

 occasion of the remarkable gales of the 25th and 26th October 

 last. In the Sydney Morning Herald of the 27th October, 

 appeared the following telegram from Adelaide : 



" Heavy gale here yesterday, (25th) commencing at JST.TO3., 

 min. bar. 29.150 at 4.15 p.m. ; wind soon after veered round to 

 W., blowing very hard throughout the night. Bar. at 10 p.m., 

 29.310, but falling after midnight ; 28.990 at 9 a.m. (26th) at 

 Mount Gambier ; 29.160 at Adelaide at 11 a.m., still falling 

 slightly." The dates in parenthesis are inserted by me for the 

 sake of explanation. Compare the above observations with the 

 state of the weather as recorded by myself at Windsor. Light 

 north-easterly winds prevailed on the 25th, with a falling 

 barometer ; at 9 a.m. on that day, it stood at 29.906, (corrected 

 for temperature) and during the following twenty-four hours, fell 

 to 29.342 or 0.564 of an inch. The wind freshened at 9 a.m. on 

 the 26th, and blew a gale, varying from ]N".E. to N.W., the 

 barometer in the meantime falling rapidly. The wind was 

 remarkable for its numerous circuitous sweeps, blowing frequently 

 from every point of the compass in succession. From half-hourly 

 observations on the 26th, the lowest corrected reading of the 

 barometer was found to be 29.021 at 3 p.m. Forty-five minutes 

 after the minimum was attained, the wind veered to west, and 

 blew in heavy gusts during the afternoon, the barometer oscilla- 

 ting, but on the whole, rising slowly. It, however, began to go 

 down rapidly again after 9 p.m., falling 0.08 inch in an hour and 

 a half, the wind, then light, having backed to IST.W. It rose 

 slowly after 2 a.m. on the 27th. Heavy W. and W.S.W. winds 

 continued throughout the 27th, the barometer still rising. Now 

 it fortunately happens, that at both Adelaide and Windsor, three 

 prominent features of the storm were recorded, viz : a first and 



