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.
Very simple and ordinary technique. This, however, reduces the length of the rope by half. Some knots could have served the purpose better.
