oasted along Mull
till we reached _Gribon_, where is what is called Mackinnon's cave,
compared with which that at Ulinish[891] is inconsiderable. It is in a
rock of a great height, close to the sea. Upon the left of its entrance
there is a cascade, almost perpendicular from the top to the bottom of
the rock. There is a tradition that it was conducted thither
artificially, to supply the inhabitants of the cave with water. Dr.
Johnson gave no credit to this tradition. As, on the one hand, his faith
in the Christian religion is firmly founded upon good grounds; so, on
the other, he is incredulous when there is no sufficient reason for
belief[892]; being in this respect just the reverse of modern infidels,
who, however nice and scrupulous in weighing the evidences of religion,
are yet often so ready to believe the most absurd and improbable tales
of another nature, that Lord Hailes well observed, a good essay might be
written _Sur la credulite des Incredules_.

The height of this cave I cannot tell with any tolerable exactness; but
it seemed to be very lofty, and to be a pretty regular arch. We
penetrated, by candlelight, a great way; by our measurement, no less
than four hundred and eighty-five feet. Tradition says, that a piper and
twelve men once advanced into this cave, nobody can tell how far; and
never returned. At the distance to which we proceeded the air was quite
pure; for the candle burned freely, without the least appearance of the
flame growing globular; but as we had only one, we thought it dangerous
to venture farther, lest, should it have been extinguished, we should
have had no means of ascertaining whether we could remain without
danger. Dr. Johnson said, this was the greatest natural curiosity he had
ever seen.

We saw the island of Staffa, at no very great distance, but could not
land upon it, the surge was so high on its rocky coast[893].

Sir Allan, anxious for the honour of Mull, was still talking of its
_woods_, and pointing them out to Dr. Johnson, as appearing at a
distance on the skirts of that island, as we sailed along. JOHNSON.
'Sir, I saw at Tobermorie what they called a wood, which I unluckily
took for _heath_. If you shew me what I shall take for _furze_, it will
be something.'

In the afternoon we went ashore on the coast of Mull, and partook of a
cold repast, which we carried with us. We hoped to have procured some
rum or brandy for our boatmen and servants, from a publick-house near