512 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



rivers and larger creeks, cool the surrounding atniospherc during- the night, 

 while the waters of the streams, retaining their warmth, send upward a 

 plentiful evaporation. The vapor which is thus formed, rising into contact 

 with the overhanging colder air, is condensed into fog and floats above the 

 streams till the morning sun sets it in motion, m- dissipates it by increas- 

 ing the temperature of the air along the mountain sides. 



The phenomena of the fog at Olayton can now be easily explained. The 

 Little Tennessee River takes its rise in Rabun Gap, and runs northwest. 

 By the junction of several large creeks, heading in the Blue Ridge, the 

 river, soon after emerging from that mountain, becomes quite a considera- 

 ble stream. It is walled in on each side by other mountains, of fifteen 

 hundred to twenty-five hundred feet in height, which extend northward, as 

 cross-ties, from the Blue Ridge to the Great Smoky Mountain. These 

 mountains are covered with forest-trees from the base to the summit. The 

 sun, during the hottest hours of the day, teems down its rays into the val- 

 ley, and imparts a great amount of heat to the waters of the river, as well 

 as to the rocks among which it runs. The temperature of the water is 

 thus kept up during the night, while at the same time, the surrounding 

 mountains cool the overhanging air. The vapor which rises rapidly from 

 the heated water coming into contact with the cold atmosphere above, is 

 converted into fog. As the sun rises in the morning his rays at once act 

 upon the air south of the Blue ridge, where no obstruction exists; but his 

 heat cannot affect that of the narrow valley of the Tennessee, till the sun 

 attains a sufficient elevation to overcome the altitude of the mountain upon 

 its eastern side. The rarefaction of the atmosphere on the south side of 

 the Blue Ridge, while that of the Tennessee valley remains at a lower 

 temperature, produces a current of air from north to south that bears the * 

 fog along with it through Rabun Gap. But here the increased heat expand- 

 ing the air or gas, in the globules of vapor composing the fog, bursts the 

 bubbles, and the fog is dissolved by absorption into the warmer atmos- 

 phere, as transparent vapor. 



The fog which rolled through the notch into Tuskegee Cove, had, no 

 doubt, formed the night previous in the valley of Cheoah River, lying to 

 the west and running northward. Overshadowed by high mountains, the 

 atmosphere of that river must have been cooler than that of the Cove into 

 which the sun was brightly shining. Two masses of air, both of which 

 must have been saturated with vapor, being thus brought into contact, 

 the temperature was diminished and the e.vcess of moisture precipitated. 



Tellulah Creek taking its rise southward, near Nantahala River, is the 

 main branch of the Cheoah River. Big Snow-bird, Little" S no w-Bird and 

 other considerable streams are its tributaries. The Lidiaa names are of 

 Cherokee origin. 



Water Spouts. 



In this connection another meteorological phenomenon, occurring in the 

 mountains of North Carolina and Tennessee, may bo noticed. It is not 

 one of the peaceful nature of the fog and rain, but, though limited in its 

 range, must be terrific bej'ond conception. An eye witness describing one 

 of these scenes to the writer, conveyed a most vivid impression of the , 



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