Once more the quest was resumed, the "Aphrodite" keeping on the surface except when a passing vessel was sighted. As secrecy was an essential point Captain Restronguet took no risks, and the submarine was submerged several times during each day. Early opportunity was taken to thoroughly overhaul the detector, and on taking the sensitive gear to pieces the fault was discovered. It was caused by a thin strand of the insulated copper wire protruding from the amalgam covering and thus setting up a short circuit. In a way that was a matter for congratulation, as it showed that the defect was no way due to magnetic disturbances caused by the heavy thunderstorm, as Captain Restronguet fully expected it to be. On the other hand the apparatus controlling the potential current of electricity that could instantaneously destroy a hostile vessel by detonating her powder was for the time being beyond remedy. This was a grave business, but the belt of electric fluid that rendered the "Aphrodite" immune from torpedo attack was still in an efficient state. Had the current been in action when the "Vorwartz" rammed her rival the effect would have been fatal to the former, since, herself a huge torpedo, the submarine would have spontaneously exploded. Shortly after rounding Cape Guadafui the "Aphrodite" once more came in touch with the "Vorwartz," the detector indicating that the latter was within eighty miles. Two hours later Kenwyn, who was keeping watch on deck, reported that he heard the distinct sound of small arms firing. Captain Restronguet, Devoran, Hythe, and several of the crew were on deck as soon as they heard the news. The sound was apparently coming from a place about twenty miles to the west. "That’s nothing to do with the ’Vorwartz,’ sir," suggested the chief officer. "I am not so sure about that," replied the captain. "It may have some connexion with that scoundrel Marburg’s villainies. We will run in and see what is amiss." "Submerged, sir?" "No; on the surface. Time and speed are to be considered." As the "Aphrodite" came in sight of the coast--a low-lying expanse of sand dunes fringed with a belt of milk-white surf--the hull of a large vessel could be distinguished. Ere long those on the submarine made out that the ship was aground and was heeling at a dangerous angle. She was funnelless, being driven by internal combustion engines. Her masts were still standing, though threatening to go by the board as each sullen roller thrashed against her lofty sides. Hoisted half way to her mainmast head was the Red Ensign--upside down--as a signal of distress.