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led the Blowing cave. It is in the side of a liill, is of 

 about 100 feet diameter, and emits constantly a current 

 of air, of such force, as to keep the weefls prostrate to 

 the distance of twenty yards before it. This current is 

 strongest in dry, frosty weather, and in long spells of 

 rain weakest. Regular inspirations and expirations of 

 air, by caverns and fissures, have been probably enough 

 accounted for, by supposing them comliined with in- 

 termitting fountains; as they must of course inhale air 

 while iheir reservoirs are emf)tying themselves, and 

 again emit it while they are filling. But a constant is- 

 sue of air, only varying in its fi)rce as the weather is 

 drier or damper, will require a new hypothesis. There 

 is another blowing cave in the Cuml)erlafid mountain, 

 about a mile from where it crosses the Carolina line. 

 All we know of this is, that it is not constant, and that 

 a fountain of water issues from it. 



The JVafural Bridge, the most sublime of nature's 

 works, though .not comprehended under the present 

 head, must not be pretermitted. It is on the ascent of 

 a hill, which seems to have been cloven throufrh its 

 length by some great convulsion. The fissure, just at 

 the bridge, is by some admeasurements, 270 feet deep, 

 by others only '205. It is about 45 feet wide at the bot- 

 tom, and 90 feet at the top : this of course determines 

 the length of the brirlire, anrl its heiirht from the water, 

 its breadth in the middle is about 60 feet, but more at 

 the ends, and the thickness of tne mass, at the summit 

 of the ar(di, about 40 feet. A part of this thickness is 

 constituted by a coat of earth, which gives jrrowth to 

 many large trees. The residue, with the hill on both 

 sides, is one soliil rock of lirrie-stone. — The arch ap- 

 proaches the senii-eliptical form ; but the larger axis 

 of the elipses, which would be the cord of the andi, 

 is many times longer than the transverse. Thougli tlie 

 sides of this bridge are [)r'v. ided in some parts with a 

 parapet of fixed rocks, yet few men have resolution to 

 walk to them, and look over into the abyss. You in- 

 voluntarily fall on your hand-^ and feet, creep to the 

 parapet and peep over it. Looking down from this 



