DATA OF PRECIPITATION. 

 Average number of rainy days. 



829 



Station. 



Jan. 



Feb. 



Mar. 



Apr. 



May. Jun<\ 



July. 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



An- 

 nual. 



Norfolk 



Capo Henry 



Hatteras 



Wilmington 



12.7 

 ll.fi 

 15. U 

 12.8 



11.0 

 9.8 

 10.2 

 10.2 



11. ti 

 12.fi 

 11.9 

 11.1 



10.7 

 11.6 



8.4 

 9.3 



11.2 

 11.8 

 10.0 

 9.9 



10.4 

 10. 5 

 9.6 

 1LI 



12.4 



Ki. i> 



10.2 

 12. C 



12.7 

 10.7 

 10.2 

 UA 



9.4 

 7.7 

 13.7 



9.9 



8.9 

 7.8 

 7.5 

 8.0 



9.9 

 9.8 

 l>. 7 

 8.3 



10.4 

 10.2 

 9.5 

 11.1 



131.3 

 125. 

 123. 8 

 128.8 



Shokk — The precipitation of snow during the winter is normally very 

 small, both in quantity and in the number of days upon which snow 

 falls. The snowfall during the winters of 1895-UO and 1806-97 was 

 as follows: 



Examples of snowfall. 



Station. 



Norfolk 



Cape Henry 

 Hatteras ... 

 Wilmington 



1895-sh;. 



1896-97. 



14.2 cm. (5.7 in.) 



9.0 cm. (3.fi in.) 



None. 



30.2cm. (12.1 in.) 



31. 2 cm. ( 12.5 ia. ) 

 28.0cm. (11.2 in.) 



None. 



None. 



The number of days in the year ended December 'A\> 1891}, upon 

 which snow fell to a depth of 2.5 mm. (0.1 inch) or more, was at 

 Norfolk, 5; at Cape Henry, U; at Hatteras, 0; at Wilmington, 2. 



Precipitation thus means chiehy rainfall in the Dismal Swamp 

 region, where the normal fall of snow in winter is too small to be of 

 any noteworthy importance to the vegetation. The normal annual 

 quantity of precipitated water is large as compared with that of most 

 other temperate regions, although it is considerably less than at Cape 

 Hatteras. The average number of days with rainfall during the year 

 is more than one-third of the whole. The distribution of precipitation 

 throughout the year, like that of atmospheric humidity, is remarkable 

 for its uniformity. The normal variation in rainfall between the 

 month of greatest; {.Inly) and that of least (November) amounts to 

 only 7 centimeters at Norfolk and about 5 at Cape Henry. The varia- 

 tion in number of days on which rain falls between the month with 

 most and that with least is likewise slight, being about four days at 

 Norfolk and five at Cape Henry. 1 



Dew. — No data regarding the amount of dew deposited could be 

 obtained, nor is this factor of primary importance to vegetation in a 

 region which possesses such an abundant and equally distributed 

 atmospheric humidity and rainfall. 



"The Dismal Swamp region belongs to Schimper's " immerfeucht Gebiet " of 

 the warm-temperate belt (Pflanzengeogiaphie, p. 500), which is characterized by 

 its rainfall being pretty equally distributed throughout the year. It is exceptional, 

 however, in that its large forest trees (excepting Pinus and Ohamaecyparis) are 

 all deciduous. Most hygrophile forest in the division thus characterized by 

 Schimper is evergreen. 



