INSIDE 157

rises above the water... As to the length of the submarine
tunnel that puts the inside in communication with the
outside, and through which the tug passes, I calculate that
it must be about forty yards.

These figures give some idea of the size of the cavern.
But vast as it is, I am aware that the Old and the New
Worlds possess others considerably larger which have
been carefully surveyed.

It is important, however, to make a aisnnction between
Backcup and all the famous caverns of the world. It is
this: the majority of these caves are easily accessible, and
must consequently have been discovered one day or
another. Now here that is not so. Indicated on the
maps of these latitudes as an island of the Bermuda group,
how could it be imagined that an enormous cavern yawned
in its interior? To know it one must enter it; and to
enter it a submarine boat analogous to the tug belonging
to Count d’Artigas is requisite.

I feel sure it was only by chance that the strange
yachtsman was led to discover this tunnel, by which he
has been enabled to found this queer colony at Backcup.

On devoting myself to the examination of the sheet of
water enclosed within the walls of the cavern, I ascertained
. that it measures three hundred to three hundred and fifty:
yards in circumference. It is in reality only a lagoon framed
in perpendicular rocks, but quite sufficient for the tug’s
manceuvres, for its depth, so far as I can discover, is not
less than forty yards.

It goes without saying that this crypt, on account of its