3L'S 



UOTANICAL SUKVKY OF DISMAL SWAMP REGION. 



It thus appears that the percentage of possible sunshine and number 

 of hours of sunshine are high as compared with other parts of the 

 Atlantic slope in North America, although generally considerably 

 lower than those recorded for stations west of the Mississippi River. 



ATMOSPHERIC HUMIDITY. 



Normal humidity in percentages of .saturation. 



Station. 



Jan. 



Norfolk 



76 

 77 

 84 

 73 



Capo H"nry 



Wilmington 



Feb. 



Mar. Apr. 



May. 

 71 



Juno. 

 71 



July. 



72 



Auk- 

 70 



Sept. 



77 



Oct. 



Nov. 

 73 



Doc. 



74 



88 68 



7") 



73 72 



78 



74 



76 



78 



7« 



74 



71 



74 



79 80 



82 



83 



83 



82 



81 



81 



79 



82 



69 68 



72 



74 



76 



80 



78 



75 



72 



73 



An- 

 nual. 



The quantity of atmospheric water normally present in the Dismal 

 Swamp region is not notably greater nor smaller than that which pre- 

 vails in other parts of the northern and middle Atlantic slope in the 

 United States, although falling considerably below the normal per- 

 centages of the coast from Charleston, in South Carolina, to Galves- 

 ton, in Texas (78 to 82 per cent). The high percentage at Cape Ilat- 

 teras is due to a local cause, the proximity at that point of the warm 

 Gulf Stream and the cold Arctic Current. On the other hand, the 

 humidity is of course far greater than in the arid and semiarid regions 

 of the Western States (42.1) per cent at Yuma, Ariz.; 4<>.2 per cent 

 at Pueblo, Colo., etc.). The distribution during the year is remark- 

 ably uniform, varying only to an extent of i) per cent between the 

 mouth of least and that of greatest normal humidity. 



PRECIPITATION. 



Ruin. — The rain-bearing storms of this region usually approach 

 from the west,. The character of the rainfall (as to intensity) varies 

 at different seasons. The winter and spring rains are usually light 

 and long continued, while the summer and fall rains are more often 

 heavy and of short duration, hence of the torrential type. 



Normal precipitation, chiefly rain. 



Station. 



Jan. 



Feb. 



Mar. 



Apr. 

 10. 17 



May. 



June. 



July. 



Aur. 



Sept. Oct. 

 11.40 ! 9.67 



Nov. 



l>l>C. 



An- 

 nual. 





9. 57 



9. 62 



11. 47 



10.7 



10.57 



14.8 



15.27 



7. 75 



9.17 



130. 2 



Norfnlk ^j n 



3.83 



3.85 



4.59 



4.07 



4.28 



4. 23 5. 92 



6.11 



4.56 | 3.87 



3. 10 



3. 67 



52.(18 



Cape Henry j m " 



10. 6 8. 9 



12 8 11.15 



1(1.17 



9.87 14.07 



13. 85 



11.37 9.47 



8.92 



9. 67 



130. 85 



4. 24 3. 56 



5. 13 



4.46 



4.<i; 



3.95 1 5.63 



5. 54 



4.55 ! 3.77 



3.57 



3. s7 



52. 34 



Hattoras... .{? m 



14.77 ,1.17 



15.25 



11.8 



11.5 



11.42 16.(17 



15.87 



16.1 15.42 



12.95 



13. 67 



166.02 



5.91 4.47 



6. 10 



4.72 



4.60 I 4.57 i 6.43 



6. 35 



6.44 ■ 6.17 



5. 18 



5. 47 



66.4] 





9.85 8.1)7 



9.87 



7.4 



10.4 14.25 18.1 18.07 



16.05 | 9.6 



6.12 



7. 45 



135. 85 



Wilmington JJ" 



3. 94 3. 23 



3. 95 



2.96 



4.16 5.70 7.24 7.47 



i ; 



6.42 3.84 



2.45 



2.98 



54. 34 



