Early on the following morning the Holland went back to her old resting place near Provincetown, and the young captain reported to his superiors what had occurred.
"You have done well," said the commodore, who received his report. "You beat them at their own game. But we must be very careful in the future, for there may be more fraudulent messages afloat."
"I would like to make a suggestion to the department," replied Oscar, modestly.
"What is it?"
"Why not have every real message marked in some peculiar and secret manner known only to those who can be trusted? Then every commander would know at once whether a message was genuine or not."
"An excellent suggestion," answered the commodore. "I will recommend that this be done."
Later on Oscar's plan was carried into effect, and by it three false messengers were caught, and later on these men were hung as spies.
Nothing had been seen of the foreign fleet since they had run to sea, but it was not long before the warships were discovered about thirty miles outside of Boston harbor.
The new Holland was at once ordered to that vicinity, "To do as much damage as possible," so the order read.
"And we'll do it," said Captain Oscar. "They'll clear out for good when we're done with them."