"Yes; you may do that--if you hear the signal shots," agreed Marshall. "But," he added, "I shall need to be very hard pressed indeed to fire my pistols. For shots at night-time anywhere near a battery would be certain to put everybody on the alert, and probably bring a bigger hornet's nest about my ears than you and all hands could beat off. Still, if I want help very badly I shall know what to do. And now, I'll be off. Keep a sharp lookout, and don't allow yourself to be surprised. Good night!" As Dick murmured an answering "Good night" the Captain turned and disappeared in the darkness. All through the night a careful watch was maintained, but nothing in the slightest degree alarming occurred; and about an hour before daybreak Captain Marshall returned, having accomplished his mission to his own complete satisfaction. "I had no difficulty whatever," he explained to Dick, "nor did I encounter a single soul; indeed I am strongly of opinion that the island, or at least the southern half of it, is uninhabited, except for the garrisons of the fort and battery. I tackled the battery first, making my way to it by passing round the base of the hill until I reached the shore-line of the next bay, which I then followed for the remainder of the distance. And heavy walking I found it, with a murrain on it; for the sand was loose and deep, except where I came upon mangroves, and there the mud was even deeper than the sand, while, as for the mosquitoes, they were as eager for my blood as the Spaniards themselves would be if they but knew what my business is here. However, I was not to be turned back by the mosquitoes, even though they assailed me in legions; and after trudging through the heavy sand for a full hour or more I found myself beneath the walls of the battery.