A correspondent, writing from Cracow, says that the famous : gait mine of Wieliczka, which brings a net annual revenue to the Austrian government of upwards of 00,000, is threat-[ ened with total destruction by a stream of water which made l its appearance on the 19th of January, while the workmen were digging in one of the lower shafts in search f potash. All the means hitherto adopted of preventing the water from inundating the mine have been unsuccessful; it flows at the rate of 120 cubic feet a minute, and has already almost filled the lower passages, rapidly dissolving the salt with which it comes in contact. A government engineer has arrived from Vienna, and a channel is being built under his directions for confining the water and leading it out of the mine, but it is feared that the salt columns which support the transverse shafts may be undermined before tin- work can be completed. These salt, mines the most renowned in the world, are situated about 8 miles from I lie city of Cracow, having their month or principal entrance in the pleasant village of Wieliczka, which lies on the slope of a wooded hill, and is very picturesque. Tin; superintendents of these mines reside here, and their dwellings, togeth r with the government ollices and large storehouses for salt, occupy a pretty eminence, and are conspicuous from a distance. A great many people from various countries visit these remarkable excavations, and are well rewarded for their trouble. Every year for many centuries having added to their depth and extent, tile mines are now of immense and almost inconceivable magnitude. In order to visit them the traveler must procure a permit from the government, which is easily done, the proper officer being on the spot. The opening or square shaft, through which the descent is made, is covered by a building or office; and here the visitor is dressed in a long coarse linen blouse, to protect his clothing while underground. A door is opened and he goes down by stairs, preceded by boys, who carry lamps only to make the darkness more visible. Or, if he is so disposed, he can descend by the windlass and ropes suspended in the center of the shaft. More frequently visitors descend by the stairways and come up by the ropes. No salt is seen for a depth of more than 200 feet; then the veins i begin to appear in a bed of clay and limestone: 50 feet further down the stairs terminate, and the salt is everywhere; nothing but salt; overhead, un der foot, on every sideare dark grey masses of solid salt, whose points and surfaces sparkle in the lamp light. Galleries now branch offin all directions. Lights twinkle, and groups of laborers are seen hacking the floors, or removing in wheelbarrows blocks that have already been cut oat. Passing on through one of these galleries a chapel is reached, which is only the first and oldest of many apartments thus designated, differing only in size and decorations. It is called the chapel of St. Anthony, and is supported by columns of salt left in quarrying the solid rock. It has an alter, crucifix, statues of saints large as life, all ot pure salt. The air in this part of the mines, near the surface, is much more moist than that of the deeper excavations, so that the process of dissolving goes on slowly, and in consequence some of these statutes of salt are gradually losing their shape. The head of one is nearly gone, the limbs of another, while dee]) furrows are observable in many places upon their bodies, making them present a very grotesque ap-; pearance when lighted up or exhibition. The smoke of the torches and lamps, added to the dampness of the air, blackens the surface of all objects not recently cut, so that these statutes might be mistaken for black marble. Onward and downward goes the visitor, through halls, chambers, tunnels innumerable. Stairs descend lower and lower, and similar apartments re-appear, till In: loses all sense of distance or direction, blindly following his conductors, who point out from time to time localities or objects of peculiar interest where all is surpassingly wonderful. Every thing 146 is solid salt, except where some insecure roof is supported by huge timbers, or a wooden bridge ia thrown over some vast chasm from which thousands of tuns of salt have been quarried and removed. The air grows drier and purer the deeper you go; the points and faces of the rock more crystalline and brilliant. One enormous hall, out of which has been cut a million hundred weight of salt, has the appearance of a theater. It is over 100 feet high, and the blocks, taken out in regular layers, represent the seats for the spectators. In another spacious vault stand two obelisks of salt, which commemorate the visit of the Emperor Francis I. and his empress. Further on you come to a lake more than 20 feet deep, intensely salt, of course, which is crossed in a heavy square boat. In this you paddle through a tunnel which connects two immense halls. While in the middle of the tunnel the walls behind you and before you are brilliantly lighted up, and a gun is discharged, which, with its echoes and reverber ations, almost deafens you. Both air and water tremble visibly under the strange and frightful concussion, and you are only too thankful to reach the end of your voyage and stand once more on solid salt. Francis Josephs ballroom is another of the wonders of this subterranean world. It is an immense apartment, both in hight and extent, and on some festive occasions is used in dancing. It is lighted by six: large chandeliers, which resemble cut glass, but are in reality of crystalline rock salt, statues of Vulcan and Neptune, sculptured from salt, al3o adorn this hall, which, well illuminated, exhibits a marvelous splendor, the light being reflected from innumerable brilliant points and angles of the glittering rock. Down, down, down hundreds of feet further, through labyrinths ot shafts, galleries and chambers, crooked passages, vaulted archways, and openings which have no name and seemingly on end. Groups of miners, naked to the hips, are everywhere busy with the implements of their darksome labors; pick, mallet, and wedge are employed incessantly in blocking out aid separating the solid mass. Their manner of work is the same simple process in use centuries ago, perhaps by the remotest ancestors of these very men, in these very mines, for they are immensely old. The blocks are marked out on the surface of the rock by grooves. One side is then deepened to the required thickness, and wedges being inserted under the block, it is soon split off. It is then divided into pieces of a hundred pounds each, and in this shape in ready for sale. It is removed in carts or barrows to the sliaft, where it is hoisted up, stage after stage, to the surface. Horsos and mules are employed, and it is said that some of these animals are born and raised in the mines. The number of laborers constantly at work is from 1,000 to 2,000. They all live outside the excavations at the present day, although traditions exist of times when the families of some of the miners had their abodes in these fearful depths, and where children were born and reared to the occupation of their parents, seldom or never visiting the outside world. The thing is neither impossible nor incredible, as the air in tie lowest part of the mines is considered more salubrious tlian in their upper regions. But the practice was long ago discontinued, if it ever existed to any extent. The miners, who are fine muscular and healthy men, are divided into gangs for work, and relieve each other every six hoars. A gang will quarry in that time about 1,000 lbs. weight. The temperature is very even all the year round, aud the preservative power of the air is such that wood never decays, but retains its qualities for centuries. People with pulmonary affections are said to have been much benefited by inhaling freely the atmosphere of the mines. When and how this wonderful deposit of salt was originally discovered is unknown. It was worked in the 12th century, and how much earlier none can tell; Some traditions are held by the ignorant and superstitious peasants of the country, which ascribe the discovery to miraculous or supernatural agency. Others say that a certain Queen of Poland, on visiting the spot, commanded her subjects to dig there, assuring them that there was a most precious treasure beneath them. After a while a crystal of salt was found, which, as an earnest of the abundance afterwards discovered, this princess had set in a ring as a royal gem, and wore to the day of her death. The extent of the deposit has not yet been fully ascertained. It commences, as we have before stated, about 200 feet below the surface, and has a solid depth of nearly 700 feet, and rests on a bed of compact limestone, such as forms the peaks of the Carpathian Mountains, which it seems to follow. It has already been explored to the continuous length of 2J miles; and it is estimated that the aggregate length of all the innumerable excavations of these- mines amounts to more than 400 rrnlee.—Mining Journal.