"Then you are going to release O'Shaunessey?"
"Not at present. He, too, will serve a good purpose. He will be able to corroborate my statement that you will be honourably treated."
"But that will be unnecessary. Surely my word----"
"I have every confidence in the word of an officer and a gentleman, Mr. Hythe. But my proposals are rarely influenced by circumstances other than the workings of Providence. You asked me a question concerning my shore agents. The answer is this: so long as the Government bestows licences upon private individuals to dabble in wireless telegraphy experiments it is a simple matter to keep in touch with events ashore. My principal agent lives in Highgate. He is a skilled operator, but he has contrived to keep his capabilities masked under the role of a harmless amateur. By advancing or retarding the spark of the powerful coil of his instrument he can 'tap' any messages, whether from British or foreign warships, within seven hundred miles, while on occasions he has accurately read messages from Cape Race. Of course, most of the naval messages are in code, and are unintelligible to the uninitiated. Nevertheless I can learn all outside news from this particular agent even when in the Mediterranean. For short distances we make use of wireless telephony, and by this means I can communicate with trusty agents in Devonport, Portsmouth, Sheet-ness and Chatham, and under certain circumstances with Rosyth and Dundee."
"Why did you come to a standstill here?" asked the sub.
"To partially recharge our accumulators. Our motive power is electricity. My invention in that direction is a revolution in marine and submarine propulsion. We are now anchored."
"Anchored?" echoed Hythe. "How? I saw no anchors when I examined your vessel from the outside."
"Anchoring, as we understand the term, consists of allowing the 'Aphrodite' to settle on the bottom of the sea. By lowering four steel plates, inclined at an angle of forty-five degrees--the acute angle facing aft--an almost irresistible brake, something after the principle of the spade recoil brake of the French quick-firing field guns, is formed. At this moment the ebb tide is swirling past at four knots. The force of the current is turning our propellers, which, acting for the time being on subsidiary shafting, drive the dynamos that in turn replenish our accumulators."
"Then that means that every day you must recharge? How do you manage when there is not sufficient tide to actuate the propellers?"
"My dear sir," replied Captain Restronguet, "I ought to have said that we were partially replenishing our reserve of electricity. At this moment there is sufficient power on board to drive the 'Aphrodite' at a speed of thirty-five knots on the surface or twenty when submerged, for a continuous period of at least one hundred and twenty hours. We merely take advantage of the opportunity to increase our reserve. But you are not eating. Is my meagre fare not sufficiently tempting?"