In the Speedwell Level, or Navigation Mine, in the vicinity of
Castleton, art has been combined with the subterraneous wonders of
nature. Being provided with lights, the guide leads the visitor beneath
an arched vault, by a flight of one hundred and six steps, to the sough
or level, where a boat is ready for his reception, and is put in motion
by pushing against pegs driven into the wall for that purpose. After
proceeding about one-third of a mile through various caverns, the level
bursts into a tremendous gulf, the roof and bottom of which are
invisible, but across which the navigation has been carried, by throwing
a strong arch over a part of the fissure where the rocks are least
separated. Here, leaving the boat, and ascending a stage erected above
the level, the attention of the visitor is directed to the dark recess
of the abyss beneath his feet; and firm indeed must be his resolution,
if he can contemplate the scene unmoved, and without an involuntary
shudder. To the depth of ninety feet all is vacuity and gloom; but
beyond that commences a pool of Stygian waters, not unaptly named the
Bottomless Pit, the prodigious range of which may in some measure be
conceived, by the circumstance of its having swallowed up more than
forty thousand tuns of rubbish, made in blasting the rock, without any
apparent diminution either of its depth or extent. The guides assert
that the former has not been ascertained; but there is reason to believe
that its actual depth in standing water is about three hundred and
twenty feet. There can not, however, be a doubt but that this abyss has
communications with others still more deeply situated in the bowels of
the mountain, and into which the precipitated rubbish has found a
passage. The superfluous water of the level falls through a water-gate
into this profound caldron, with a noise like a rushing torrent.
This fissure is calculated to be about eight hundred feet beneath the
surface of the mountain; and so great is its reach upward, that rockets
of sufficient strength to ascend four hundred and fifty feet, have been
fired without rendering the roof visible. The effect of a Bengal light
discharged in this stupendous cavity, is extremely magnificent and
interesting.