Opening Address. 13 



wards a point on the right hand of the region of lowest pressure ; 

 and it would appear that the wind in approaching this region 

 tends to turn round it, or to become vorticose. One of mj 

 correspondents in Scotland has recently sent out to me a rule 

 laid down by Dr. Ballot, by which to forecast the direction of the 

 wind on any day, from barometer readings taken on the same 

 morning at a number of near stations. The rule is to stand with 

 the place where the barometer is highest on your right hand, and 

 lowest on your left, and you will have your back to the wind that 

 may be expected during the day. This rule may perhaps require 

 to be reversed in the southern hemisphere. The force of the wind 

 is said to depend mainly on the amount of difference in the barom- 

 etrical readings at near stations. Thus a westerly gale never 

 blows with any severity over the British Islands unless, at least 

 a few hours beforehand, the pressure in the north of Scotland is 

 half an inch less than in the South of England. 



It must be apparent from these observations that no satisfac- 

 tory theory of our winds is likely to be attained without a much 

 more systematic and extensive collection and comparison of facts 

 respecting pressure, temperature, and winds than has yet been 

 attempted, and I commend this inquiry to some active member of 

 our Society who may be gifted with sufficient leisure and zeal. 



Before concluding, I wish to call your attention to a letter that 

 has been addressed to the President of our Society (His Excel- 

 lency the Grovernor) by the President of the Royal Society of 

 Yictoria, on the subject of the approaching total eclipse of the 

 sun. It is as follows : — 



Melbourne, 22nd April, 1871. 



SiE, — A proposition has been brought before this Society for a joint expe- 

 dition from the seve;'al Australian colonies to Cape York Peninsula, to 

 observe the total eclipse of the sun which will take place on the 12th of De- 

 cember next. The scientific interest of this phenomenon is very great, and 

 the points to be determined are important. As far as is known, there will be 

 no further total eclipse of the sun readily accessible from Australia during the 

 remainder of the present century. The proposal is that a steamer should be 

 chartered to start from Melbourne about the 20th of November, and, touching 

 at intermediate points, to convey such persons as may desire to witness the 

 eclipse. It is expected that the total cost will not exceed £25 per head of 

 those who form the party. It is proposed that the expedition should be under 

 the charge of the Government Astronomer, so far as the control of the steamer 

 is necessary to prevent undue delay. A Committee of this Society has been 



