The letter fell from his hands.
"Well," said Wall, "this imaginary captain says nothing about coming on board. I don't believe he ever will."
"But how did this letter get here?" asked Johnson.
Shandon was silent.
"Mr. Wall is right," answered the doctor, who had picked up the letter, and who was turning it over with hands as well as in his mind. "The captain won't come on board, and for an excellent reason."
"What is it?" asked Shandon, quickly.
"Because he's on board now," answered the doctor, simply.
"Now!" exclaimed Shandon, "what do you mean?"
"How else can you explain the arrival of this letter?"
Johnson nodded approvingly.