266 



THE PLANT COVERING OF OCRACOKE ISLAND. 



WIND. 



The average annual maximum velocity of the wind is 21.4 kilome- 

 ters (13.3 miles) per hour, as compared with 23.2 kilometers at Cape 

 Henry, 15.1 at Norfolk, and 15.4 at Wilmington. The average monthly 

 maximum velocities, stated in kilometers and miles, are as follows: 



Month. 



January. 

 February 

 March . . . 

 April 



Month. 



May ... 

 June . . . 

 July... 

 August 



Month. 



September 

 October . . . 

 November 

 December. 



Kilo- 

 me- 

 ters. 



17.2 



18.4 

 19.8 

 24.0 



Miles 



10.7 

 11.4 

 12.3 

 14.9 



In regard to direction, the winds of midwinter are usually from the 

 north, while those of midsummer are usually from a little west of 

 south. 



As thus shown, the average velocity of the wind is considerable, and 

 the amount of its variation from month to month is remarkably" slight. 

 The highest average of course prevails in winter and early spring. In 

 midwinter, when the winds are normally strongest and therefore most 

 affect the perennial, especially the woody vegetation, their prevailing 

 direction is almost due south (from the north), hence, in the case of 

 Ocracoke, from tlie mainland. 



In regard to temperature, rainfall, and atmospheric humidity the 

 climate of Ocracoke and Hatteras is suitable for a vigorous forest 

 growth. But the exposure to strong winds, and the peculiar soil con- 

 ditions, neutralize these favorable factors and give it a typical strand 

 vegetation, which much resembles that of deserts. In the neighbor- 

 hood of Norfolk and of Wilmington, where conditions of temxjerature 

 and of humidity are really somewhat less suitable than at Hatteras to 

 the most luxuriant develo]3ment of j^lants, the virgin growth is almost 

 eveiywhere dense forest, because there the inimical conditions are 

 absent. 



PHYSIOGRAPHY. 



Ocracoke Island is part of that long chain of narrow sand reefs 

 which fringes the southern Atlantic Coast of the United States, and 

 which forms the eastern bariier to a series of almost land-locked bays 

 and sounds. Ocracoke lies in longitude 76° west and latitude 35° 10' 

 north, and is therefore somewhat south of the center of the North 

 Carolina coast. It is separated from Hatteras Reef by the 0.8 kilo- 

 meter (one-half mile) wide strait known as Hatteras Inlet, and from 

 Portsmouth, the next island below, by Ocracoke Inlet, 3 kilometers 

 (nearly 2 miles) wide. Ocracoke itself is about 26 kilometers (16 

 miles) in length, and extends from that great bulge of the coast line 



