More than ten years ago a serious accident, which threatened the destruction of the mine, occurred. While boring, to obtain some potash salts, through an aquiferous stratum, a spring was tapped, which poured an immense quantity of water into the lower galleries. The inhabitants feared not only the ruin of the mine, but the falling in of their houses from the melting of the salt pillars; but fortunately the inundation was confined to the lower galleries, and a powerful steam-engine being set to work, the water was again pumped out, and the spring blocked up. However, so vast are the excavations that it would have taken many years to fill them. Contrasting with the bright glitter of the salt mines of Wieliczka are the gloomy slate quarries of Saint Peter's Mount, near Maestricht, in the Netherlands, the most extensive in the world. For centuries they have been worked, both for building and manuring, and probably benefiting the agriculturist more than the architect. In spring and summer the labourers occupy themselves in their fields above ground, and not until winter approaches do they begin to burrow in the entrails of the earth. The two travellers followed a trusty guide through those endless passages, which constantly crossed each other, either to the left hand or to the right. Darkness to be felt, silence profound, reigned everywhere, even the human voice seemed to die away without awakening an echo--the only sound to be heard being an occasional dropping of water from the roof into a small pool below. Suddenly the guide extinguished his torch, when, bold as they were, and well accustomed to subterranean regions, a sensation of awe crept over them. Their first impulse was to feel for the wall, for in vain their eyes sought a ray of light, as in vain, also, their ears listened for the slightest sound. Neither spoke for some minutes, and they experienced a sensation of relief when the guide relit his torch. Numbers of hapless beings have been lost in these trackless galleries, and here and there are inscriptions on the walls, notifying that a corpse was found on the ground below. One poor workman lost his way, and roamed about until his torch died out of his burnt fingers. The lamp of another was overturned, and he in vain endeavoured to find his way out of some remote gallery.