AQUEOUS ATMOSPHERIC PHENOMENA. 



473 



An interesting table, given by Dalton, throws light upon the phenomena of rain and 

 wind in our own country. It states, for one year, the number of days that each wind 

 prevailed at London ; the quantity of rain that fell during its prevalence ; and the rela- 

 tive humidity of the winds, or the quantity of moisture which each would deposit in the 

 same space of time. 



Thus two-thirds of the rain that fell during the year at the Metropolis, the whole 

 amount being 27'11 inches, fell with the south-west wind. The west wind was the next 

 in point of humidity, but this is the rarest after the east wind in ,our locality, while the 

 north and south winds were the driest. We should naturally expect the gales that blow 

 from the Atlantic Ocean to bring a more abundant supply of vapour than those which 

 proceed from the direction of the European continent, and also anticipate that the south- 

 western counties of England, first experiencing their influence, would be the scene of the 

 most copious rains. The preceding table confirms the former presumption, and from 

 observations made at Penzance in Cornwall, it appears that the rains which accompany the 

 west and south-west winds at that place exceed in the ratio of about three to one those 

 produced by the easterly breezes. Mr. Leslie expresses the opinion, founded upon a com- 

 parison of data obtained from various sites, that as much rain falls on the western, 

 as falls on the eastern side of the island. The smallest observed quantity is 19*5 

 inches for the year at Upminster in Essex ; the largest is 67'5, at Keswick in Cumberland. 

 A report presented at the meeting of the British Association for the present year, containing 

 the amount of rain with the different winds for five consecutive years at Toomanara, near 

 Limerick, confirms the preceding statements respecting the humidity of the winds from the 

 Atlantic, which, in that locality, include the south, south-west, and west. The following 

 are the yearly mean results deduced from the whole series of observations : 



South. 

 6-548 



S. West. 

 10-639 



West. 

 6-034 



N. West. 

 2-789 



North. 

 2-352 



N.East. 

 2-172 



East. 

 2-251 



S. East. 

 3-173 



Total. 

 35*958 inches. 



Dalton estimates the average annual quantity of rain for the whole of England at 3T3 

 inches, but this has been deemed too high. Mr. Leslie rates it at 30 inches ; and, 

 according to this estimate, 1,944,633. or nearly two millions of tons of water, are annually 

 discharged from the clouds on every square mile of surface, or 3000 tons for each English 

 acre, a quantity equal to 630,000 imperial gallons. 



Taking a larger area of our part of the hemisphere, Professor Schow estimates the 

 annual amount of rain north of the Alps to be 26 inches, and 37 inches south of the chain ; 

 but it must be remembered that the greater proportion of snow falls on the northern 

 side. 



It may be useful and interesting to throw into a tabular form the results of observations 

 respecting the yearly deposit of water in different parts of the globe. 



Sweden 



Russia 



England 



Upsal ; - 

 St. Petersburg 

 London - 

 Manchester 

 Liverpool 

 Dover * 



Inches. 



- 16--92 



- 18-11 



- 22 '7 



- 33-07 



- 33-85 



- 374 



Scotland 



Norwich - 

 Upminster 

 Kendal - 

 Keswick - 

 Edinburgh 

 Glasgow - 



Inches. 



- 25-5 



- 19-5 



- 60 



- 67-5 



- 22 



- 22'32 



