"Available as far as the Germans would permit," corrected the sub deferentially. "They've had full control here for years. I'm not referring to the lagoon, but to the river. The depths, too, are inaccurate." "I suppose you wouldn't object to a job to-morrow?" asked the senior officer, after he had listened intently to Denbigh's explanations and descriptions of the details of the Mohoro River. "Not in the least, sir," replied the sub promptly. "In a sea-plane?" "Just my mark, sir; but I've had no flying experience." "We would want you for registering duties," continued Captain Holloway. "You will have a flight sub-lieutenant as pilot. With your knowledge of the shore batteries and torpedo stations you will be able to render further important service. Very good; I'll arrange for the sea-plane to pick you up at dawn; that is, if it is not too misty. These tropical mists play the deuce with aerial observations." It was arranged that the attack should open at seven on the following morning. The _Crustacean_ was to lead the way over the inner bar, and devote her attention to the torpedo station. The _Paradox_ was to shell the batteries concealed in the mangrove forest, while the _Eureka_ was to patrol the lagoon and to cut off any attempt at flight on the part of the German troops, whose line of retreat would be pretty certain to be along the coast, since the thick forests and marshes to the westward made retirement to the hinterland almost a matter of impossibility. Two hours before sunrise the crews of the monitors were called to "action" stations. They had previously bathed and changed into clean clothes, and had been given ample time to enjoy their breakfast. Clearing ship for action took but little preparation, since the monitors carried only what was necessary as floating batteries. At the hour specified a sea-plane taxied gracefully to within fifty feet of the _Crustacean_. A boat was lowered from the monitor, and into this Denbigh stepped, to the accompaniment of the somewhat irrelevant remarks of his brother officers. "Fine mornin'," was the flight-sub's greeting, as nonchalantly as if he were passing the time of day with a casual acquaintance. "Hop in. You'll find a belt fixed to the back of your seat. There's the wireless gear. See that lever on your left? That releases the paying-out gear of the aerial. Don't pay out too smartly. Ready?" The blades glittered in the morning light as the propeller revolved and rapidly increased the number of revolutions. Slowly at first, then with accelerated movement, the sea-plane skimmed the placid surface of the lagoon. Then, almost before Denbigh was aware of it, the machine leaped upwards. The slight tilt of the seat was the only intimation that the sea-plane had parted company with the water, until the sub noticed the surface of the lagoon apparently receding with great rapidity.