"It was!" and the lad was now almost as excited as was his friend.

"Then I've seen it and, what's more, this morning! Bless my spark
plug, I've seen it!"

"Tell me about it!" pleaded the young inventor, and Mr. Damon, calming
himself after an effort, resumed:

"I was out for an early spin in my auto," he said, "and was traveling
along a road that bordered the lake, about fifteen miles above here. I
heard a motor-boat puffing along near shore, and, looking through the
trees, I saw one containing three men. It had a red arrow on the bow,
and that's why I noticed it, because I recalled that your boat was
named the DART."

"ARROW," corrected Tom.

"The ARROW. Oh, yes, I knew it was something like that. Well of
course at the time I didn't think that it was your boat, but I
associated it in my mind with yours. Do you catch my meaning?"

Tom did and said so, wishing Mr. Damon would hurry and get to the
point. But the eccentric character had to do things in his own way.

"Exactly," he resumed. "Well, I didn't think that was your boat, but,
at the same time, I watched the men out of curiosity, and I was struck
with their behavior. They seemed to be quarreling, and, from what I
could hear, two of them seemed to be remonstrating with the third one
for having taken some sort of a piece of wood from the forward
compartment. I believe that is the proper term."

"Yes!" Tom almost shouted. "But where did they go? What became of
them? What was the man doing to the forward compartment--where the
gasoline tank is?"

"Exactly. I was trying to think what was kept there. That's it, the
gasoline tank. Well, the boat kept on up the lake, and I don't know
what became of the men. But about that piece of wood. It seems that
one of the men removed a block, from under the tank and the others
objected. That's why they were quarreling."

"That's very strange," exclaimed the lad. "There must be some mystery
about my boat that I don't understand. But that will keep until I get
the boat itself. Good-by, Mr. Damon. I must be off."

"Where to?"

"Up the lake after those thieves. I must lose no time," and Tom
started to go back to where he had left the RED STREAK.

"Hold on!" cried Mr. Damon. "I have something to propose, Tom. Two
heads are better than one, even if one doesn't know how to adjust a
nutmeg grate. Suppose I come along with you? I can point out the
direction the men took, at any rate."

"I'll be ver