"Well, your men will find the body of Lieutenant Scott lying on a couch there. In that case, they will doubtless arrest the two boys I left on watch there?"
"Certainly."
"And that will give the man who left this blur on the arm of this chair not long ago a chance to make off with the boat. I reckon you'll do well to look after that part of the case, for the submarine belongs to the Secret Service department of the Government, and Uncle Sam has use for it just at this time."
"The Secret Service department?" repeated the chief. "He said she was a scout boat Lieutenant Scott was going to coast south with."
"Did he say why he suspected that Lieutenant Scott was in danger?" asked Ned.
"He said you boys were suspicious characters who claimed to be able to operate a submarine, and that Scott was inclined to try you out."
Ned took a long envelope from a pocket of his coat and passed it, unopened, to the chief.
"Read the letter inside," he said, "and then get me to the Sea Lion as quickly as possible."
The chief opened the envelope and read the single sheet of typewritten paper it held.
"From the Secretary of the Navy!" he exclaimed.