the boy is
near death yet. I must give him heroic treatment. I will call an
ambulance."

"All right, doc. You know best. But I don't know what I'm going to do,"
and Jim Tracy shook a puzzled head. "The crowd will expect the tank
act--he didn't do more than start it. It's been advertised all over the
country. I don't know where I can get some one to take his place. This
sure is hard luck, though, of course, it isn't Ben's fault, and I want
you to take the best care of him you can. But who in the world can I
put in on the tank act?"

"Put me in," said Joe Strong in a quiet voice.

"You?" cried Jim Tracy.

"Yes," answered the young acrobat "I can fill in all right. Let me
finish out Benny's tank act."

CHAPTER III

JOE IN THE TANK

Jim Tracy seemed hardly to know whether or not Joe was in earnest. They
stood together, a little distance away from the cot on which lay Benny
Turton, only just recovering consciousness.

"Do you really mean it, Joe?" asked the ring-master.

"I certainly do," was the answer. "I don't say I can do all the tricks
Ben did, for I haven't practised them. But I may be able to improvise a
few of my own."

"But can you stay under water as long as he could, Joe? That's the
point. You know we bill him as remaining under a fraction over four
minutes, and challenge the world to produce his equal. We even invite
the public to hold their watches and keep time for themselves.

"As a matter of fact, Ben never stayed under more than four minutes,
though he once, in his earliest attempts, did make it four even. But
the public isn't very critical on that point. As a rule the women get
nervous, and I've often heard some of 'em call out to him not to drown
himself.

"But the crowd would surely expect the act to last three minutes under
water--I mean three minutes at a time. Can you do that?"

"I think I can. In fact I can do better than three minutes."

"Are you sure, Joe?"

"Yes, sure."

"Of course he is," broke in a new voice, and Joe and the ring-master
turned to see Helen Morton standing beside them. She had finished her
act some time before.

"I heard that something had happened to Benny," she said, "and I came
in to see if I could do anything. I heard what you and Joe were saying,
Jim, and I couldn't help speaking as I did. I know Joe can stay under
water more than three minutes."

"How?" asked the ring-master. He seemed dazed by the way things were
happening. "How do you kno