reached a trolley line that ran into
Atlantis, and they arrived at the city before Mr. Damon and Tom got
there, as the latter had to go by a circuitous route. Mr. Berg lost no
time in calling up his firm by telephone.

"I have had another talk with Mr. Swift," he reported to Mr. Bentley,
who came to the instrument in Philadelphia.

"Well, what does he say?" was the impatient question. "I can't
understand his not wanting to try for the Government prize. It is
astonishing. You said you were going to discover the reason, Mr Berg,
but you haven't done so."

"I have."

"What is it?"

"Well, the reason Mr. Swift and his son don't care to try for the fifty
thousand dollar prize is that they are after one of three hundred
thousand dollars."

"Three hundred thousand dollars!" cried Mr. Bentley. "What government
is going to offer such a prize as that for submarines, when they are
getting almost as common as airships? We ought to have a try for that
ourselves. What government is it?"

"No government at all. But I think we ought to have a try for it, Mr.
Bentley."

"Explain."

"Well, I have just learned, most accidentally, that the Swifts are
going after sunken treasure--three hundred thousand dollars in gold
bullion."

"Sunken treasure? Where?

"I don't know exactly, but off the coast of Uruguay," and Mr. Berg
rapidly related what he had overheard Tom tell Mr. Damon. Mr. Bentley
was much excited and impatient for more details, but his agent could
not give them to him.

"Well," concluded the senior member of the firm of submarine boat
builders, "if the Swifts are going after treasure, so can we. Come to
Philadelphia at once, Mr. Berg, and we'll talk this matter over. There
is no time to lose. We can afford to forego the Government prize for
the chance of getting a much larger one. We have as much right to
search for the sunken gold as the Swifts have. Come here at once, and
we will make our plans."

"All right," agreed the agent with a smile as he hung up the receiver.
"I guess," he murmured to himself, "that you won't be so high and
mighty with me after this, Tom Swift. We'll see who has the best boat,
after all. We'll have a contest and a competition, but not for a
government prize. It will be for the sunken gold."

It was easy to see that Mr. Berg was much pleased with himself.

Meanwhile, Tom and Mr. Damon had reached Atlantis, and had purchased
the oil. They started back, but Tom took a street leading