Proceeding onward about one-hundred feet, we reached a door, set in a rough stone wall, stretched across and completely blocking up the Cave; which was no sooner opened, than our lamps were extinguished by the violence of the wind rushing outwards. An accurate estimate of the external temperature, may at any time, be made, by noting the force of the wind as it blows inward or outward. When it is very warm without, the wind blows outwards with violence; but when cold, it blows inwards with proportionate force. The temperature of the Cave, (winter and summer,) is invariably the same—59° Fahrenheit; and its atmosphere is perfectly uniform, dry, and of most extraordinary salubrity.
Our lamps being relighted, we soon reached a narrow passage faced on the left side by a wall, built by the miners to confine the loose stone thrown up in the course of their operations, when gradually descending a short distance, we entered the great vestibule or ante-chamber of the Cave. What do we now see? Midnight!—the blackness of darkness!—Nothing! Where is the wall we were lately elbowing out of the way? It has vanished!—It is lost! We are walled in by darkness, and darkness canopies us above. Look again;—Swing your torches aloft! Aye, now you can see it; far up, a hundred feet above your head, a grey ceiling rolling dimly away like a cloud, and heavy buttresses, bending under the weight, curling and toppling over their base, begin to project their enormous masses from the shadowy wall. How vast! How solemn! How awful! The little bells of the brain are ringing in your ears; you hear nothing else—not even a sigh of air—not even the echo of a drop of water falling from the roof. The guide triumphs in your look of amazement and awe; he falls to work on certain old wooden ruins, to you, yet invisible, and builds a brace or two of fires, by the aid of which you begin to have a better conception of the scene around you. You are in the vestibule or ante-chamber, to which the spacious entrance of the Cave, and the narrow passage that succeeds it, should be considered the mere gate-way and covered approach. It is a basilica of an oval figure—two-hundred feet in length by one-hundred and fifty wide, with a roof which is as flat and level as if finished by the trowel of the plasterer, of fifty or sixty or even more feet in height. Two passages, each a hundred feet in width, open into it at its opposite extremities, but at right angles to each other; and as they preserve a straight course for five or six-hundred feet, with the same flat roof common to each, the appearance to the eye, is that of a vast hall in the shape of the letter L expanded at the angle, both branches being five-hundred feet long by one-hundred wide. The passage to the right hand is the "Great Bat Room;" (Audubon Avenue.) That in the front, the beginning of the Grand Gallery, or the Main Cavern itself. The whole of this prodigious space is covered by a single rock, in which the eye can detect no break or interruption, save at its borders, where is a broad, sweeping cornice, traced in horizontal panel-work, exceedingly noble and regular; and not a single pier or pillar of any kind contributes to support it. It needs no support. It is like the arched and ponderous roof of the poet's mausoleum:
"By its own weight made stedfast and immoveable."
The floor is very irregularly broken, consisting of vast heaps of the nitrous earth, and of the ruins of the hoppers or vats, composed of heavy planking, in which the miners were accustomed to leach it. The hall was, in fact, one of their chief factory rooms. Before their day, it was a cemetery; and here they disinterred many a mouldering skeleton, belonging it seems, to that gigantic eight or nine feet race of men of past days, whose jaw-bones so many vivacious persons have clapped over their own, like horse-collars, without laying by a single one to convince the soul of scepticism.
Such is the vestibule of the Mammoth Cave,—a hall which hundreds of visitors have passed through without being conscious of its existence. The path, leading into the Grand Gallery, hugs the wall on the left hand; and is, besides, in a hollow, flanked on the right hand by lofty mounds of earth, which the visitor, if he looks at them at all, which he will scarcely do, at so early a period after entering, will readily suppose to be the opposite walls. Those who enter the Great Bat Room, (Audubon Avenue,) into which flying visitors are seldom conducted, will indeed have some faint suspicion, for a moment, that they are passing through infinite space; but the walls of the Cave being so dark as to reflect not one single ray of light from the dim torches, and a greater number of them being necessary to disperse the gloom than are usually employed, they will still remain in ignorance of the grandeur around them.
Such is the vestibule of the Mammoth Cave, as described by the ingenious author of "Calavar," "Peter Pilgrim," &c.
From the vestibule we entered Audubon Avenue, which is more than a mile long, fifty or sixty feet wide and as many high. The roof or ceiling exhibits, as you walk along, the appearance of floating clouds—and such is observable in many other parts of the Cave. Near the termination of this avenue, a natural well, twenty-five feet deep, and containing the purest water, has been recently discovered; it is surrounded by stalagmite columns, extending from the floor to the roof, upon the incrustations of which, when lights are suspended, the reflection from the water below and the various objects above and around, gives to the whole scene an appearance equally rare and picturesque. This spot, however, being difficult of access, is but seldom visited.
The Little Bat Room Cave—a branch of Audubon Avenue,—is on the left as you advance, and not more than three-hundred yards from the great vestibule. It is but little more than a quarter of a mile in length, and is remarkable for its pit of two-hundred and eighty feet in depth; and as being the hibernal resort of bats. Tens of thousands of them are seen hanging from the walls, in apparently a torpid state, during the winter, but no sooner does the spring open, than they disappear.
Returning from the Little Bat Room and Audubon Avenue, we pass again through the vestibule, and enter the Main Cave or Grand Gallery. This is a vast tunnel extending for miles, averaging throughout, fifty feet in width by as many in height It is truly a noble subterranean avenue; the largest of which man has any knowledge, and replete with interest, from its varied characteristics and majestic grandeur.
Proceeding down the main Cave about a quarter of a mile, we came to the Kentucky Cliffs, so called from the fancied resemblance to the cliffs on the Kentucky River, and descending gradually about twenty feet entered the church, when our guide was discovered in the pulpit fifteen feet above us, having reached there by a gallery which leads from the cliffs. The ceiling here is sixty three feet high, and the church itself, including the recess, cannot be less than one hundred feet in diameter. Eight or ten feet above and immediately behind the pulpit, is the organ loft, which is sufficiently capacious for an. organ and choir of the largest size. There would appear to be something like design in all this;—here is a church large enough to accomodate thousands, a solid projection of the wall of the Cave to serve as a pulpit, and a few feet back a place for an organ and choir. In this great temple of nature, religious service has been frequently held, and it requires but a slight effort on the part of a speaker, to make himself distinctly heard by the largest congregation.