miles of air pass over the sbitioii. The sensitiveness of the machine to 

 the action of the wind may be judged of from the fact, that there were 

 only nineteen hours in the year 1852, during which the horizontal 

 windmill ceased to record the motion of the air, and it is remarkable 

 that four of these hours occun*ed on the 9th of November, the day 

 on which the shock of an earthquake was felt in this neighbourhood. 



The worked paper is preserved for future reference, but the principal 

 results are tabulated. I have the pleasure of exhibiting to the Society 

 this evening both the original records and the tabulated results. Those 

 for the year 1852, which I have the honour to present to the Society, 

 have been deduced from the tabulated hourly results. In table I, they 

 ai-e arranged according to the hours of the day. Column 2, contains 

 the average horizontal motion of the air for the year, between any 

 one hour of the day and the next hour following, from which it will 

 be seen that the minimum velocity of the air is between midnight 

 and 1 a.m., and the maximum velocity between the hours of 1 and 2 p.m. 

 the former is eleven miles and two- tenths of a mile, and the latter 

 fifteen and a half miles an hour. The velocity of the air appears to 

 gradually increase from a little after midnight to a little after noon, 

 and to gradually diminish from a little after noon to a little after mid- 

 night. The mean hourly horizontal motion of the air for the year is 

 thirteen miles; and if we consider this to equal 1*00, the minimum 

 velocity will be represented by 0'86, and the maximum by 1*19, as 

 shewn in column 8 ; therefore the horizontal motion of the air between 

 the hours of 12 and 1 a.m. is thirty-three per cent, less than it is 

 between the hours of I and 2 p.m. ; column 4 shews the whole quantity 

 of rain, in inches, which fell between any one hour of the day and the 

 next hour following during the year, and column 6 the time in hours 

 during which rain fell; column 5 shews the relative fall of rain, and 

 column 7 the relative time duiing which rain fell, on the assumption 

 that the average is equal to unity ; column 8 shews the average hourly 

 rate at which rain fell between any one hour of the day and the next 

 hoiur following. 



In table II the results are arranged according to the direction of the 

 wind. Column 2 shews the whole amount of air which passed over the 

 observatory during the year, referred to sixteen points of the compass, 

 and column 4 the number of hours that the wind blew from each point. 

 13y an inspection of these two columns, it will be seen that the direction 

 of the wind was referred to the S.S.E, point one thousand five hundred 

 and six hours, or sixty-two days eighteen hours, and that the whole 

 amount of air which passed over the observatory from that point was 

 eighteen thousand one hundred and eleven miles ; the largest amount of 



