Its almost perpendicular walls were bristling with innumerable projections which would facilitate the descent.

But if there was no want of steps, still there was no rail.
A rope fastened to the edge of the aperture might have helped us down.

But how were we to unfasten it, when arrived at the other end?
My uncle employed a very simple expedient to obviate this difficulty.
He uncoiled a cord of the thickness of a finger, and four hundred feet long; first he dropped half of it down, then he passed it round a lava block that projected conveniently, and threw the other half down the chimney.

Each of us could then descend by holding with the hand both halves of the rope, which would not be able to unroll itself from its hold; when two hundred feet down, it would be easy to get possession of the whole of the rope by letting one end go and pulling down by the other.

Then the exercise would go on again _ad infinitum_.
"Now," said my uncle, after having completed these preparations, "now let us look to our loads.