Grey dawn revealed the battered _Rebound_, still steaming stern-foremost, within the wide estuary of the Rio Guaya. Four miles to the west'ard lay her three sister-battleships, with their attendant light cruisers and destroyers, awaiting daybreak before pushing on up the broad river as far as they could without violating the territorial waters of San Valodar and San Benito. There was a widely expressed hope amongst the officers and crew of the British fleet, that one of these republics would throw in her lot with the enemy. That would leave the admiral a comparatively free hand, since he would no longer be obliged to respect the zone over which either San Valodar or San Benito claimed jurisdiction. As things stood, there was a curious anomaly. The Rioguayan fleet had the right to the free use of the river below Sambrombon Island, although both passages were controlled by neutral states. Until the British fleet could contrive to obtain sanction, they were unable to proceed much farther without causing an international affair which might call for protests from the Powers. The British air squadron attached to the fleet was also unable to approach Rioguayan territory, owing to the republic's possession of Brian Strong's anti-aircraft rays. On their part the Rioguayan flying-boats were useless against the British fleet, armed as it was with the ray-projecting apparatus. The only course open, apparently, was to blockade Rioguay by sea, but this promised to be a most unsatisfactory operation. The republic was practically self-supporting; it could still maintain trade with the neighbouring republics despite any active interference on the part of the British navy. The defeat at sea hardly troubled President Jaime Samuda. It was a regrettable occurrence, from a national point of view, but he still hoped for great things from the powerful aerial armada of the republic. Even if air-power failed, he could still hope that the ineffectual blockade would be maintained until either the British got tired of "watching the mouse-hole", or else became involved in embarrassing complications elsewhere. His own position seemed so secure that never for one moment did President Jaime Samuda think seriously upon the possibility of a revolution. Corbold and Cavendish had completed their "trick", Their reliefs had taken over and they were on their way below to enjoy a well-earned sleep. Just as they were about to enter the battery door, there was a shout of "periscope one point on the starboard bow!" For the present, the stern of the ship was considered to be the bows for manoeuvring purposes, consequently the starboard side became the port and vice versa. The two chums ran to the rail and, leaning out, could discern the object in question at a distance of about two hundred yards from the ship.