166 Results, of a Meteorological Journal, [March, 



EVAPORATION. 



Indies. 



Greatest quantity, in June 6-60 



Smallest ditto, in January 0-30 



Total quantity evaporated in the year 34-13 



RAIN. 



Inches. 



Greatest quantity, in August 4-67 



None in April (see the state of the Winds.) 



Total quantity that fell here in the year 30-57 



N. B. The barometer is hung in the Observatory, about 30 

 feet above the level of the sea ; and the thermometer is placed 

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

 the garden ground. The pluviameter stands clear of all obstruc- 

 tions on the top of the Observatory, 22 feet above the garden 

 ground ; and the evaporation vessel, near the same place, is 

 exposed to the sun and wind in dry weather. For brevity's sake, 

 the four cardinal points only are put down in the table, to show 

 the number of days the winds have blown from each quarter in 

 each month. 



With regard to the difference in the state of the weather 

 between 1816 and 1817 ; this year we find that the quantity of 

 rain is two inches less than that of the preceding, and the quan- 

 tity of evaporation 1 1-J- inches more. Now, the comparative 

 difference in the two years' rain is not of much consequence ; 

 but it must be admitted that the additional quantity of evapora- 

 tion, which is nearly half as much more as in 1816, is a surpris- 

 ing difference, and will, in some measure, account for the 

 retardation of solar influence that year, perhaps from the spots 

 on the sun, or the cavities in his atmosphere, which were veiy 

 numerous in the spring and summer months, and in some 

 instances prodigious, as ascertained by our own observations. 

 The number of rainy days is also less this year than the preced- 

 ing, by 15 ; but the number of brilliant and cloudless days is 

 nearly on a par. 



The annual mean state of the barometer is *171, or nearly 

 •^ -ths of an inch higher ; and the annual mean height of the 

 thermometer between 2° and 3° more : these favourable indica- 

 tions further corroborate the ungenial weather of that year. 



The annual mean barometrical pressure from three observations 

 each day is as follows : at eight o'clock A.M. 30-002 inches ; 

 at two P.M. 30-005 inches j and at eight in the evening, 30-017 

 inches. Thus, from eight in the morning- till eight in the even- 

 ing, a small rise of the mercury has been discovered ; but 

 notwithstanding the increase from eight A.M. till two P.M. the 

 jnercury, from one hour before till two hours after noon, suffers 

 % simultaneous depression of about -j-^th of an inch (in summer 



