They then both set to work trying to discover some way of fastening it by which it would not slip down the rope.

They made many fruitless attempts; each time that a strand was fastened with a loop large enough for them to pass a leg through, it slid down the rope when their weight was applied to it.

At last they succeeded in finding out a knot which would hold.

This was done by tying a knot close to one end of a piece of the strand, then sufficient was left to form the loop, and the remainder was wound round the rope in such a way that the weight only served to tighten its hold.
"Shall we begin at once ?" Ralph said, when success was achieved.
"No, we had better wait until nightfall.

The vibration of the rope when our weight once gets on it might be noticed by anyone crossing the courtyard." "Do you think we have sufficient bits of rope," Ralph asked.
"Just enough, I think," Walter replied; "there were six strands, and each has made six pieces, so we have thirty-six.