The sharks had grown bolder, too, now. All about them they could see the flash of greeny-white bodies as the sea monsters slowly circled the boat, as if making up their minds from which side to attack it first.
"Beadt on der vater mit your hands," counselled the German. "Dose sharks iss pig cowards undt maype vee scare dem off for a vile."
Nat beat his hands furiously on the water, churning it into foam, and, as Captain Nelsen had predicted, the sharks—even the boldest of them—sheered off. But it was only for a short time. They presently reappeared and seemed to be bolder than before.
Nat gazed at them with frank alarm, and Captain Nelsen was scarcely less perturbed. Although they both beat on the water now and made all the noise they could, the sharks seemed to be growing less and less afraid of them. Nat could almost see a contemptuous gleam in the creatures' piggy little eyes as they swam round the boat.
All at once one of them, seeming to tire of this aimless circling, made a sudden dash at the craft. Nat fairly shouted with alarm and perhaps his cry scared the creature off. At any rate, they were saved for that time, but it grew very evident that before long a moment would arrive when they could no longer hold the creatures at bay.
It was just then that the captain gave a shout.
"Idiotcy dot I voss," he yelled, so that Nat thought he had lost his mind under the stress of their situation; "idiotcy dot I voss. Dere is somedings in dis very boadt dot vill drive dose fellows avay."
"What do you mean?" demanded the astonished Nat.
"Dot der last time dis boat vos used vos ven ve vos painting der ship sides. Ve didt not finish der chob before ve had to sail, undt a big can of acid vot vee use for cleaning off der oldt paint vos put in dot stern locker."
"In that box under the seat?" asked Nat excitedly, half guessing what the captain was driving at.