"Certainly," Virginia exclaimed, "if I had not heard of a similar effect produced in the Mammoth Cave, I should never have believed that marvellous chorus was sung by a single voice!"
"A single woice!" repeated Carl, incredulous. "There vas more as a dozen woices!"
"Right, Carl!" laughed Penn. "The first was Cudjo's; and all the rest were those, of the nymph Echo and her companions."
They continued their course through the halls of the echoes, and soon came to an arched passage, at the entrance of which Penn paused and placed the torch in a niche. A projection of the rock prevented the light from shining before them, yet their way was softly illumined from beyond, as by a dim phosphorescence. They advanced, and in a moment their eyes, grown accustomed to the obscurity, came upon a scene of surprising and magical beauty.
"The Grotto of Undine," said Penn.
It was, to all appearances, a nearly spherical concavity, some thirty yards in length, and perhaps twenty in perpendicular diameter. Carl's torch was concealed in the niche, and Cudjo's was nowhere visible; yet the whole interior was luminous with a dim and silvery halo. A narrow corridor ran round the sides, and resembled a dark ring swimming in nebulous light, midway between the upper and nether hemispheres of the wondrous hollow globe. Within this horizontal rim, floor there was none; and they stood upon its brink; and, looking up, they saw the marvellous vault all sparkling with stars and beaming with pale, pendent, taper, crystalline flames, noiseless and still; and, looking down, beheld beneath their feet, and shining with a yet more soft and dreamy lustre, the perfect counterpart of the vault above.
Penn held Virginia upon the verge. A bewildering ecstasy captivated her reason as she gazed. They seemed to be really in the grotto of some nymph who had fled the instant she saw her privacy invaded, or veiled the immortal mystery and loveliness of her charms in some mesh of the glimmering nimbus that baffled and entangled the sight. Save one or two stifled cries of rapture from Virginia and Carl, not a syllable was uttered: perfect stillness prevailed, until Penn said, in a whisper,—
"Wouldst thou like to see the face of Undine? Bend forward. Do not fear: I hold thee!"
By gentle compulsion he induced her to comply. She bent over the brink, and looked down, when, lo! out of the hazy effulgence beneath, emerged a face looking up at her—a face dimly seen, yet full of vague wonder and surprise—a face of unrivalled sweetness and beauty, Penn thought. What did Virginia think?—for it was the reflection of her own.
"O, Penn! how it startled me!"