“It ought to be an easy matter to trace them,” said the lawyer. “Their motor boat must be registered and licensed, as ours must be. We can trace them through that, I think. Neale, would you know the men if you saw them again?”

“I might,” answered the boy. “I didn’t have a very good look at them, though. They both had their backs toward me, and their hats were pulled down over their faces. As Ruth says, however, they looked rough and desperate.”

“We must take some action,” declared the lawyer, with his characteristic energy. “The authorities must be notified and that motor boat traced. We shall have to stop here to register our own craft and get a license, and it will give us an opportunity to make some inquiries.”

“Meanwhile those men will get away!” exclaimed Ruth. “And we’ll never get our jewelry back. If we could get mother’s ring,” she added, “it wouldn’t be so bad.”

“They can’t get very far away if they stick to the river,” said Mr. Howbridge. “The river flows into Lake Macopic and there is no outlet from that. If we have to pursue the men all the way to the lake we’ll do it.”

“Well, then let’s get busy,” suggested Neale. “The sooner we have our boat registered and licensed, the sooner we can start after those men. Of course we can’t catch them, for their boat goes so much faster than ours. But we can trace them.”

“I hope we can,” murmured Ruth, gazing up the river, on which there was now no trace of the boat containing the rough men. “We have two quests, now,” she added. “Looking for our jewelry box, and your father, Neale. And I hope we find your father, whether I get back my things or not—anything but the ring.”

“Let us hope we get both,” said the boy.

Then followed a busy hour. Certain formalities had to be gone through with, in order to enable the Bluebird to make the voyage on the river and lake. Her motor was inspected and passed. Neale had seen to it that the machinery was in good shape.

Mr. Howbridge came back from the boat registry office with the necessary permit and license, and Ruth asked him: