He reared up with an ugly roar, and his little eyes shot flames of fire at his adversaries.

He offered a fair mark as he stood erect, and Jack had an inspiration. Hanging over the side of the Water Sprite was one of the life-preservers, the round type, a circle with a very large opening in the center, so that it could be easily slipped over the head.

Jack snatched it up and threw it with the motion of a quoit-thrower. It covered the short intervening distance and went over the bear’s head, settling on his neck and looking for all the world like a gigantic ruff. It gave the animal a most grotesque appearance, and the spectators roared with laughter.

It was easier for it to go on than it was for the bear to get it off, and his antics were comical as he rubbed his head against the trees and, failing in that, took his paws to it. He succeeded at last, but his naturally surly nature had not been improved by the operation, and the instant the life-preserver was dislodged, he rushed to the edge of the shore and plunged into the water.

The action was so sudden that the party was taken by surprise. The girls screamed, and the boys had to do some quick work to get the Water Sprite under way. They succeeded, however, and once the engine was going, it was an easy matter to keep out of the bear’s reach, although for so clumsy a creature he swam with amazing swiftness.

They could have distanced him without trouble, but with deliberate purpose Jack kept just far enough ahead of him to encourage him in thinking that he might overtake his quarry. In this way, he drew him down along the shore of the lake for more than half a mile. By that time, Bruin’s ardor had cooled and his strength began to fail. He gave a wrathful snort and made for the shore.

The instant he did so, Jack turned the boat about and made all speed back to the place where they had been surprised.

“Now’s our chance, fellows,” he said. “We can get there long before the bear does, even if he makes a bee line for it as soon as he gets to shore. I’ll hold her bow against the bank, while you jump out and gather up the provisions and bring them on board. That thief may have got our fish, but he won’t have the laugh on us altogether.”

It was very quick work that Paul and Walter did, for they had no mind to be caught there when the bear should make his way back, as they had no doubt he would. They regained the life preserver, which was so scratched and torn that it was no longer good for its original purpose, but they wanted it as a memento of the adventure.

As the bear had not had time to meddle with the food laid out by the girls, they were not so badly off after all, although it was exasperating to have to go without the fish, whose appetizing aroma was still in the air.