Dr. Ward, provided with guides, two large lamps, a compass and refreshments, descended a pit forty feet in depth, and one hundred and twenty in circumference; having a spring of fine water at the bottom, and conducting to the entrance of the cavern. The opening, which is to the north, is from forty to fifty feet high, and about thirty in width. It narrows shortly after, but again expands to a width of thirty or forty feet, and a hight of twenty, continuing these dimensions for about a mile, to the first _hoppers_,[2] where a manufactory of saltpeter had recently been established. Thence to the second of these hoppers, two miles from the entrance, it is forty feet in width, and sixty in hight. Throughout nearly the whole of the distance handsome walls had been made by the manufacturers, of the loose limestone. The road was hard, and as smooth as a flag pavement. In every passage which the doctor traversed, the sides of the cavern were perpendicular, and the arches, which have bid defiance even to earthquakes, were regular. In 1802, when the heavy shocks of earthquakes came on which were so severely felt in this part of Kentucky, the workmen stationed at the second hoppers, heard about five minutes before each shock, a heavy rumbling noise issue from the cave, like a strong wind. When that ceased, the rocks cracked, and the whole appeared to be going in a moment to final destruction. However, no one was injured, although large portions of rock fell in different parts of the cavern. ----- Footnote 2: A hopper is an inverted cone, into which corn is put at a mill before it runs between the stones. ----- In advancing into the cavern, the avenue leads from the second hoppers, west, one mile; and thence, south-west, to the chief area or city, which is six miles from the entrance. This avenue, throughout its whole extent from the above station to the cross-roads, or chief area, is from sixty to one hundred feet in hight, of a similar width, and nearly on a level, the floor or bottom being covered with loose limestone and saltpeter earth. “When,” observes the doctor, “I reached this immense area (called the chief city) which contains upward of eight acres, without a single pillar to support the arch, which is entire over the whole, I was struck dumb with astonishment. Nothing can be more sublime and grand than this place, of which but a faint idea can be conveyed, covered with one solid arch at least one hundred feet high, and to all appearance entire.” Having entered the area, the doctor perceived five large avenues leading from it, from sixty to one hundred feet in width, and about forty in hight. The stone walls are arched, and were from forty to eighty feet perpendicular in hight before the commencement of the arch.