judges five hundred thousand pounds of faltpetre might be collected annually. MEDICINAL SPRINGS. There are feveral medicinal springs, fome of which are indubitably efficacious, while others feem to owe their reputation as much to fancy, and change of air and regimen, as to their real virtues. None of them have undergone a chemical analysis in fkilful hands, nor been fo far the fubject of obfervation, as to have produced a reduction into claffes, of the diforders which they relieve; it is in our power to give little more than an enumeration of them. The most efficacious of thefe are two fprings in Augusta, near the fources of James river, where it is called Jackson's river. They rife near the foot of the ridge of mountains, generally called the Warm Spring mountain, but in the maps Jackson's mountains. The one is diftinguished by the name of the Warm Spring, and the other of the Hot Spring. The Warm Spring iffues with a very bold stream, fufficient to work a grift mill, and to keep the waters of its bafon, which is thirty feet in diameter, at the vital warmth, viz, 96° of Fahrenheit's thermometer. The matter which these waters is allied to is very volatile; its fmell indicates it to be fulphureous, as alfo does the circumftance of turning filver black: they relieve rheumatisms: other complaints also of very different natures have been removed or leffened by them. It rains here four or five days in every week. The hot fpring is about fix miles from the warm, is much smaller, and has been fo hot as to have boiled an egg. Some believe its degree of heat to be leffened: it raises the mercury in Fahrenheit's thermometer to 112, which is fever heat; it fometimes relieves where the warm fpring fails. A fountain of common water, issuing within a few inches of its margin, gives it a fingular appearance. Comparing the temperature of thefe with that of the hot springs of Kamfcatka, of which Krachininnikow gives an account, the difference is very great, the latter raising the mercury to 200°, which is within 12° of boiling water. Thefe fprings are very much resorted to, in fpite of a total want of accommodation for the fick. Their waters are strongest in the hotteft months, which occafions their being visited in July and Auguft principally. The sweet springs are in the county of Botetourt, at the eastern foot of the Allegany, about forty-two miles from the warm fprings, They They are ftill lefs known. Having been found to relieve cafes in which the others had been ineffectually tried, it is probable their compofition is different: they are different alfo in their temperature, being as cold as common water; which is not mentioned, however, as a proof of a diftinct impregnation. This is among the first fources of James river. On the Potomack river, in Berkeley county, above the North mountain, are medicinal fprings, much more frequented than those of Augufta: their powers, however, are lefs, the waters weakly mineralised, and scarcely warm. They are more vifited, because fituated in a fertile, plentiful and populous country, provided with better accommodations, always fafe from the Indians, and nearest to the more populous States. In Louisa county, on the head waters of the South Anna branch of York river, are fprings of fome medicinal virtue; they are, however, not much used. There is a weak chalybeate at Richmond, and many others in various parts of the country, which are of too little worth, or too little note to be enumerated after those before mentioned. We are told of a fulphur spring on Howard's creek of Greenbriar. In the low grounds of the Great Kanhawa, feven miles above the mouth of Elk river, and fixty-feven above that of the Kanhawa itfelf, is a hole in the earth of the capacity of thirty or forty gallons, from which issues constantly a bituminous vapour, in so strong a current, as to give to the fand about its orifice the motion which it has in a boiling Spring. On prefenting a lighted candle or torch within eighteen inches of the hole, it flames up in a column of eighteen inches diameter, and four or five feet in height, which sometimes burns out in twenty minutes, and at other times has been known to continue three days, and then has been left burning. The flame is unfteady, of the denfity of that of burning fpirits, and fmells like burning pit coal. Water fometimes collects in the bafon, which is remarkably cold, and is kept in ebullition by the vapour iffuing through it; if the vapour be fired in that state, the water foon becomes fo warm, that the hand cannot bear it, and evaporates wholly in a fhort time. This, with the circumjacent lands, is the property of Prefident Washington and of General Lewis. There is a fimilar one on Sandy river, the flame of which is a column of about twelve inches diameter and three feet high. Gene ral Clarke kindled the vapour, ftaid about an hour, and left burning. The mention of uncommon fprings leads to that of Syphon fountains there is one of thefe near the interfection of the Lord Fairfax's boundary with the North mountain, not far from Brock's gap, on the ftream of which is a grift mill, which grinds two bufhels of grain at every flood of the spring. Another near the Cow Pasture Fiver, a mile and a half below its conflunce with the Bull Pasture river, and fixteen or feventeen miles from the hot springs, which intermits once in every twelve hours. One alfo near the mouth of the North Holfton. After these may be mentioned, the Natural Well on the lands of a Mr. Lewis, in Frederick county; it is fomewhat larger than a common well; the water rifes in it as near the furface of the earth as in the neighbouring artificial wells, and is of a depth as yet unknown. It is faid, there is a current in it tending fenfibly downwards; if this be true, it probably feeds fome fountain, of which it is the natural refervoir, diftinguished from others, like that of Madifon's cave, by being acceffible; it is ufed with a bucket and windlafs as an ordinary well. CAVERNS AND CURIOSITIES. In the lime-stone country there are many caverns of very confifiderable extent. The most noted is called Maddifon's cave, and is on the north fide of the Blue ridge, near the interfection of the Rockingham and Augufta line with the fouth fork of the southern river of Shenandaoh. It is in a hill of about two hundred feet perpendicular height, the afcent of which, on one fide, is fo fteep, that you may pitch a biscuit from its fummit into the river which washes its bafe. The entrance of the cave is, in this fide, about two-thirds of the way up. It extends into the earth about three hundred feet, branching into fubordinate caverns, fometimes afcending a little, but more generally defcending, and at length terminates in two different places, at bafons of water of unknown extent, and which appear to be nearly on a level with the water of the river. The water in these bafons is always cool, it is never turbid, nor does it rife or fall in times of flood or drought. It is probably one of the many refervoirs with which the interior parts of the earth are fuppofed to abound, and which yield fupplies to the fountains of water, diftinguifhed from } from others only by its being acceffible. The vault of this cave is of folid lime-stone, from twenty to forty or fifty feet high, through which water is continually percolating. This, trickling down the fides of the cave, has incrufted them over in the form of elegant drapery; and dripping from the top of the vault, generates on that, and on the base below, ftalactites of a conical form, fome of which have met and formed maffive columns. Another of these caves is near the North mountain, in the county of Frederick. The entrance into this is on the top of an extenfive ridge. You defcend thirty or forty feet, as into a well, from whence the cave then extends, nearly horizontally, four hundred feet into the earth, preserving a breadth of from twenty to fifty feet, and a height of from five to twelve feet. Mr. Jefferson obferves, that after entering this cave a few feet, the mercury, which in the open air was at 50°, rose to 57° of Fahrenheit's thermometer, answering to 11° of Reaumur's, and it continued at that to the remotest parts of the cave. The uniform temperature of the cellars of the observatory of Paris, which are ninety feet deep, and of all fubterranean cavities of any depth, where no chymical agents may be supposed to produce a factitious heat, has been found to be 10° of Reamur, equal to 54 of Fahrenheit. The temperature of the cave above mentioned fo nearly correfponds with this, that the difference may be ascribed to a difference of inftruments. At the Panther gap, in the ridge which divides the waters of the Cow and Calf pafture, is what is called the Blowing Cave. It is in the fide of a hill, is of about an hundred feet diameter, and emits constantly a current of air of fuch force, as to keep the weeds proftrate to the distance of twenty yards before it. This current is frongest in dry frosty weather, and weakeft in long periods of rain. Regular infpirations and expirations of air, by caverns and fiffures, have been probably enough accounted for, by fuppofing them combined with intermitting fountains, as they muft of course inhale the air while the refervoirs are emptying themfelves, and again emit it while they are filling. But a conftant iffue of air, only varying in its force as the weather is drier or damper, will require a new hypothefis. There is another blowing cave in the Cumberland mountain, about a mile from where it croffes the Carolina line. All we know of this is, that it is not conftant, and that a fountain of water iffues from it. The The Natural Bridge is the moft fublime of nature's works. It is on the ascent of a hill, which seems to have been cloven through its length by fome great convulfion. The fiffure, juft at the bridge, is by fome admeasurements two hundred and feventy feet deep, by others only two hundred and five. It is about forty-five feet wide at the bottom, and ninety feet at the top; this of course determines the length of the bridge, and its height from the water. Its breadth in the middle is about fixty feet, but more at the ends, and the thicknefs of the mafs at the fummit of the arch about forty feet, but more at the ends, and ninety feet at the top. A part of this thickness is constituted by a coat of earth, which gives growth to many large trees. The refidue, with the hill on both fides, is folid rock of lime-ftone. The arch approaches the femielliptical form; but the larger axis of the ellipfis, which would be the cord of the arch, is many times longer than the tranfverfe. Though the fides of this bridge are provided in fome parts with a parapet of fixed rocks, yet few men have refolution to walk to them and look over into the abyfs. You involuntarily fall on your hands and feet, creep to the parapet and peep over it. If the view from the top be painful and intolerable, that from below is delightful in an equal extreme. It is impoffible for the emotions arifing from the fublime, to be felt beyond what they are here: fo beautiful an arch, fo elevated, fo light, and fpringing as it were up to Heaven, the rapture of the fpectator is really indefcribable! The fiffure continuing narrow, deep and ftraight, for a confiderable distance above and below the bridge, opens a short but very pleafing view of the North mountain on one fide, and Blue ridge on the other, at the distance each of them of about five miles. This bridge is in the county of Rockbridge, to which it has given name, and affords a public and commodious paffage over a valley, which cannot be croffed elsewhere for a confiderable diftance.* The stream paffing under it is called Cedar creek. It is a water of James river, and sufficient in the driest seasons to turn a grift mill, though its fountain is not more than two miles above. There is a natural bridge fimi Don Ulloa mentions a break, fimilar to this, in the province of Angarez, in South-America. It is from fixteen to twenty-two feet wide, one hundred and eleven deep, and of one mile and three quarters continuance, English meafure. Its breadth at top is not fenfibly greater than at bottom. lar |