RAIN. 



RAIN. 



tity that falls, and the manner in which it falls, 

 are the circumstances to be attended to. A 

 great number of rainy days are more injurious 

 to the soil, even where the quantity is not 

 great, than heavy falls at distant intervals of 

 time; the ground, in the first case, being con- 

 stantly over-saturated, its fertility is much less- 

 ened ; in the other, the superfluous moisture 

 being soon drained off, only the portion neces- 

 sary for the nourishment of plants is left, which 

 is gradually given out in dry weather, during 

 which the ground for a time is in its most pro- 

 ductive state. 



In general, more rain falls in the north of 

 England than in the south. The east and 

 southeastern counties have usually the driest 

 seasons and years. The fall of rain is various, 

 however, at any period of the year, as may be 

 seen from the annexed tables. The mean quan- 

 tity falling annually in England is reckoned to 

 be 32 inches, or, according to Dalton, 31-3; but 

 this is unequally distributed. 



The annual amount in Westmoreland and 



Lancashire, according to Mr. Whistlecraft, 

 usually ranges from above 40 to nearly 70 

 inches, while that noted by the gauge in Essex 

 and Suffolk is as low as from 14 Io32 inches ; 

 seldom, however, does it exceed 25 inches. It 

 may, indeed, be fairly inferred, that these two 

 parts of England produce extremes. 



Mr. Howard gives the annual average al 

 London equal to 24-9 inches ; Professor Phil- 

 lips at York 25-7; and Mr. Adie at Edinburgh 

 25 inches. 



At Keswick, in Cumberland, the depth on an 

 average of 7 years was found to be 67 inches; 

 at Baverstock, near Salisbury, during the same 

 period, 32$ inches ; and at Plymouth, in De- 

 vonshire, 45 inches. In the western parts of 

 Scotland the depth is from 30 to 35 inches, 

 which is from 6 to 10 inches more than that 

 on the east coast. 



The mean monthly and annual quantities of 

 rain at various places, deduced from the ave- 

 rage for many years, by Dalton, is given in the 

 following table : 



The greatest depth of rain which has been 

 registered at any place in a year, is at Maran- 

 ham, lat. 2$ S., and which is stated by Hum- 

 boldt to be 277 English inches. But this is 

 greatly above the average, and, indeed, more 

 than double the annual quantity which has 

 been observed at any other locality. At St. 

 Domingo, the annual fall is estimated at 120 

 inches; at Cayenne, 116 inches; at the Ha- 

 vana, 91; at Calcutta, from 76 to 118; at Bom- 

 bay, from 83 to 96; the island of Martinique, 

 87 inches ; and at Sierra Leone, 86. Of Eu- 

 ropean countries, Portugal appears to be the 

 most humid, 123 inches having been observed 

 at Coimbra in a year. 



Although winter usually produces more rainy 

 days than summer, the quantity of rain which 

 falls is greater in the latter season. Dr. Dal- 

 ton has ascertained that the first six months of 

 the year may be regarded as dry, and the last 

 six as wet months. Another ingenious author 

 has inferred, from long observation, that in 

 spring it rains oftener in the evening than in 



the morning, but that towards the end of sum- 

 mer, oftener in the morning than in the even- 

 ing. At St. Petersburg, rain and snow fall on 

 an average 84 days of the winter, and the 

 'quantity amounts to about 5 inches; on the 

 contrary, the summer produces 11 inches in 

 the same number of days. In Canada, the 

 average fall of rain usually is about 3 feet, 

 which furnishes about 20 gallons of water for 

 each square foot of surface during the year. 



In the United States, the quantity of rain 

 falling per annum increases in going south. At 

 Philadelphia, a medium point, the results of 

 33 years' observation of the rain-gauge have 

 been estimated by Mr. Owen Evans as fol- 

 lows: Whole quantity, from 1810 to 1842 in- 

 clusive, 1276-435 inches; annual mean or ave- 

 rage, 38-68 inches; greatest amount in any one 

 year, 55-278 inches (in 1841); smallest quan- 

 tity, 23-354 inches (in 1819). 



Mr. Evans has also constructed the follow- 

 ing table, showing the monthly averages of. 

 rain, estimated for 5 years (1838 to 1842 in- 



939 



