"Ship the periscope, Carclew. Directly you sight any small Government craft bearing down this way let me know. And Gwennap, get this letter ready for delivery." The periscope consisted of a double-wedge shaped instrument connected to the top of the after conning-tower by means of a flexible armoured insulated wire. Carclew, by switching off the current from an electro-magnet, allowed the float to rise to the surface, where, owing to the comparatively slow rate of the submarine, it was towed without being dragged under. As soon as this was done another switch was manipulated, and instantly a reproduction of the surrounding objects was faithfully projected by an advanced form of telephotography upon a dull white board fixed to the wall of the conning-tower. "There’s a black pinnace with a yellow awning coming down stream, sir," announced Carclew. "She’s got the letters M.P. on her bows." "Police launch evidently," said Captain Restronguet. "Now Gwennap, stand by. Are we right under her course, Carclew?" The man Gwennap had meanwhile placed the document in an oiled covering which in turn he lashed to a globular white and green buoy. This he placed in an ejector, made on the principle of a submerged torpedo tube. "All ready, sir," he announced. Captain Restronguet held up his hand, and receiving an affirmative gesture from the seaman at the periscope-board, nodded his head. There was a slight, almost inaudible hiss and the buoy with the message attached, was ejected out of the conning-tower, rising to the surface within fifty yards of the on-coming launch. "They’ve picked it up, sir," declared Carclew, after half a minute had elapsed. "That’s well," murmured the captain, as he descended the conning-tower ladder. "I wonder if the reply will be in a similar strain to the one I received five years ago. Ah! I wonder." And with a grave smile on his resolute features Captain Restronguet returned to his cabin. "Send Mr. Hythe to me," he ordered, when a seaman appeared in answer to his summons. "And tell the diving-party detailed for duty to have the boat ready for launching; warn Polglaze and Lancarrow to stand by at eleven to-night." "Now, Mr. Hythe," said Captain Restronguet, when the sub was shown into the cabin, "I may as well tell you that I have reported your presence and that of the able seaman to the Commander-in-Chief, and doubtless I shall have a reply before noon to-morrow. If you would like to see our periscope in working order now is a good opportunity. We are travelling dead slow, and there is plenty to be seen here--more so than at sea." "It is a picture," exclaimed the sub enthusiastically, as he gazed upon the electrically-depicted panorama. "The whole horizon is included; but how do you know in what direction an object is lying?"