They marched on, and presently launched the catamaran. It would only support one at a time astride and half in the water, but it was a capital thing. Sitting on it, Bevis paddled along the shore nearly to the rocky wall and back, but he did not forget his promise, and was not out of his depth; he could see the stones at the bottom all the time. Mark tried to stand on the plank, but one edge would go down and pitch him off. He next tried to lie on it on his back, and succeeded so long as he let his legs dangle over each side, and so balanced it. Then they stood away, and swam to it as if it had been the last plank of a wreck.
"Look!" said Mark, after they had done this several times. He was holding the plank at arm's length with his limbs floating. "Look!"
"This is the way. We ought to have held the jumping-pole like this. This is the way to hold an oar and swim."
"So it is," said Bevis, "of course, that's it; we'll have the punt, and try with a scull."
Held at arm's length, almost anything will keep a swimmer afloat; but if he puts it under his arm or chest, it takes a good-sized spar. Splashing about, presently the plank forgotten for the moment slipped away, and, impelled by the waves they made, floated into deep water.
"I'm sure I could swim to it," said Bevis, and he was inclined to try.
"You stupe--I know that; but if there's a plank, that's not dangerous then."
"Stupe" was their word for stupid. He waded out till the water was over his shoulders, and tried to lift him.
"Don't--don't," said Mark. Bevis began to lean his chest on the water.
"If you're captain," cried Mark, "you ought not to."
"No more I ought," said Bevis, coming back. "Get my bow."
Mark was caught by his own argument, and went out on the sward for the bow.
"Tie the arrow on with the string," shouted Bevis. Mark did it, and brought it in, keeping it above the surface. Bevis climbed on the railings, half out of water, so that he could steady himself with his knees against the rail.
"Now, give me the bow," he said. He took good aim, and the nail, filed to a sharp point, was driven deep into the soft deal of the plank. With the string he hauled the catamaran gently back, but it would not come straight; it slipped sideways (like the boomerang in the air), and came ashore under the aspen bough.