I throw its light upon the stalactites which drape the lofty roofs.
Shut off the lamp, and you are in the blackest darkness. Turn it on, and
it is a scene from the Arabian Nights.

But there is one of these strange openings in the earth which has a
special interest, for it is the handiwork, not of nature, but of man. I
had never heard of Blue John when I came to these parts. It is the name
given to a peculiar mineral of a beautiful purple shade, which is only
found at one or two places in the world. It is so rare that an ordinary
vase of Blue John would be valued at a great price. The Romans, with
that extraordinary instinct of theirs, discovered that it was to be
found in this valley, and sank a horizontal shaft deep into the mountain
side. The opening of their mine has been called Blue John Gap, a
clean-cut arch in the rock, the mouth all overgrown with bushes. It is
a goodly passage which the Roman miners have cut, and it intersects some
of the great water-worn caves, so that if you enter Blue John Gap you
would do well to mark your steps and to have a good store of candles, or
you may never make your way back to the daylight again. I have not
yet gone deeply into it, but this very day I stood at the mouth of the
arched tunnel, and peering down into the black recesses beyond, I vowed
that when my health returned I would devote some holiday to exploring
those mysterious depths and finding out for myself how far the Roman had
penetrated into the Derbyshire hills.

Strange how superstitious these countrymen are! I should have thought
better of young Armitage, for he is a man of some education and
character, and a very fine fellow for his station in life. I was
standing at the Blue John Gap when he came across the field to me.

"Well, doctor," said he, "you're not afraid, anyhow."

"Afraid!" I answered. "Afraid of what?"

"Of it," said he, with a jerk of his thumb towards the black vault, "of
the Terror that lives in the Blue John Cave."

How absurdly easy it is for a legend to arise in a lonely countryside! I
examined him as to the reasons for his weird belief. It seems that from
time to time sheep have been missing from the fields, carried bodily
away, according to Armitage. That they could have wandered away of their
own accord and disappeared among the mountains was an explanation to
which he would not listen. On one occasion a pool of blood had been
found, and some tufts of wool. That also, I pointed out, could