Meteorological Summarij for 1824. — Hampshire. 157 



Least monthly quantity in January .... 0*77 In. 

 Total amount for the year 32*75 



Rai7i. 



Greatest monthly depth in November . . 5*305 



Least monthly depth in January .... 0*990 



Total depth tor the year near the ground . 40*057 



Total depth for the year 23 feet high . . 35*549 



N. B. The barometer is hung up in the observatory 50 feet 



above the low-water mark of Portsmouth Harbour; and the 



self-registering horizontal day and night thermometer, and De 



Luc's whalebone hygrometer, are placed in open-worked cases, 



in a northern aspect, out of the rays of the sun, 10 feet above 



the garden ground. The pluviameter and evaporator have 



respectively the same square ai-ea : the foi'mer is emptied every 



morning at 8 o'clock after rain, into a cylindrical glass gauge 



accurately graduated to y^oth of an inch ; and the quantity 



lost by evaporation from the latter is ascei'tained at least every 



third day, and sometimes oftener, when great evaporations 



happen by means of a high temperature and dry northerly or 



easterly winds. 



Barometrical Pressure. — The maximum pressure was 

 higher this year by g jth of an inch than it was in 1823, and the 

 minimum pressure was less by g'o'-'^ ^^ ^" inch. The mean 

 pressure this year is j^^ths of an inch less than that of last 

 year, but it agrees with the mean pressure for the last 10 years 

 within yjj'y ^ths of an inch. The aggregate of the spaces de- 

 scribed by the alternate rising and falling of the mercury is 

 S\ inches greater than that of last year ; and the number of 

 changes is 21 more. — For 173 days in which the moon ranged 

 in North declination, the mean pressure was j§yths of an inch 

 greater than that in the 1 83 days in which she ranged in South 

 declination. 



The mean barometrical pressures for the last six years, while 



the moon was in North and South declination, are as follow : 



With the moon in North declination . 29*885 inches. 



With tlie moon in South declination . 29*845 inches . 



Increased pressure for her position North 1 „^ 



of the Equinoctial J 



Here I must observe that this difference of j'jth of an inch 

 in the elevation of the barometer, by the superior weight of 

 the atmosphere while the moon was in iwrlh declination, is 

 not sullicient, in a local point of view, to produce any sensible 

 effects over the atmospliere in respect to the weather in this 

 latitude ; and that the difference in the course of a longer 

 series of years might, perhaps, become inconsiderable, and 



thus 



