But when, almost simultaneously, he heard the shriek of a projectile, his interest became aroused. It was part of his duty to warn ships, when, as sometimes happened, the ricochetting shells pitched against the chalk cliff, of the possible danger to life and property of His Majesty's liege subjects. "Bill!" he shouted to his opposite number, who was industriously engaged in mending frayed signal flags in the room under the look-out place. "Stand by to 'oist 'height nought nine'. The _Spanker_--'er wot went out this mornin'--is a-lobbin' 4.7's ashore." Having shared the responsibility of taking action, the signalman applied his eye to a large telescope mounted on a tripod. From his elevated post, the look-out hut being 350 feet above sea-level, the horizon line was roughly twenty-five miles away. The sea was calm, the atmosphere clear, except for a few patches of mist that threatened to develop into a sea-fog. There was but one vessel in sight. She proved to be a tramp bound up-channel. There were no signs of the light cruiser _Spanker_. Even as he looked, came another faint report. The man, by reason of long experience, knew that it was not a quick-firer. The interval was too great for that. The unusual pitch of the whine of the projectile puzzled him. Suddenly a long, low-lying dark object appeared in the field of the high-powered telescope. "Gosh!" ejaculated the bluejacket, "s'elp me if she ain't a perishin' submarine." Even as he looked, he saw a long, slender object rise from the for'ard deck of the distant vessel. Slowly but unhesitatingly it moved until the watcher found himself gazing down the muzzle of a gun. Instinctively he shut his eyes, forgetting that a distance of about fifteen miles separated him from that menacing ring of metal. When he looked again, the gun had been trained to an elevation of nearly forty-five degrees. There was a flash... thirty seconds later he heard the report. Twice more the gun was discharged; then the mysterious vessel submerged. The spell was broken as far as the signalman was concerned. Clamping the telescope, so that it remained trained upon the spot where he had seen the submarine disappear, he shouted to his mate, who was leisurely bending the hoist of flags to the signal halliards. "Belay there," he exclaimed excitedly. "Get on the telephone to the C.-in-C. There's a bloomin' submarine been shellin' Pompey." His opposite number looked up languidly and solemnly winked his eye. "'Tain't the fust of April, mate," he remarked in mild reproof. "D'ye want ter get me 'ung, or what not?" Ten minutes later, the Commander-in-Chief at Portsmouth was informed by wireless telephony from Culver Cliff of something that he was already well aware of--that five shells had been fired at the principal naval port of the British Empire. In addition, he learnt that the shells came from a submarine, nationality unknown, operating 16 miles S. 1/2 E. magnetic from Culver Cliff Signal Station.