"This is our wireless room," said the captain, raising his voice to make it audible above the succession of sharp reports like the crack of a whip. "No overhead gear to be carried away in action or in a gale; our wireless messages are received by an electrical current passing through water. The apparatus is merely an extension of the submarine signalling system. We are in touch with our agents at Swanage in England, Plougastel in Brittany, Cape Cod in the U.S.A., and ere long with Sydney, N.S.W., and Antofagasta in Chili. Thus we are well informed of events that are likely to call for our intervention." "Then that is how you learned the result of your experiments with the _Zietan_, is it not?" asked Tregarthen. "A shrewd guess, only it happens to be wrong," replied Captain Brookes. "However, I'll enlighten you on this point." From the wireless room he led the way for'ard, between walls of steel that doubtless contained more wonders of mechanical triumph. Passing the cable lockers he dived down a narrow hatchway, leading still deeper into the bowels of the ship, till he arrived at the door of a wedge-shaped room corresponding with the bow of the vessel. Here was a table on which were several electrical coils and a pair of dials resembling galvanometers. "Here you are," continued the captain. "What do you make of this contrivance?" "I cannot say," replied Gerald, still nettled by the failure of his previous conjecture. "That apparatus gives us warning when we are passing over a submarine cable. It used to be an accepted fact that the insulation of our deep sea cables is so perfect that the 'leakage' is infinitesimal, but by this instrument we can detect their presence in any depth down to one hundred fathoms. This done, it is a comparatively simple matter to grapple for the cable, hoist it to the surface and tap it. The great disadvantage is that the ship must be brought almost to a standstill to enable the 'detector' to act, and, of course, wholly so while the wire is being brought on board." "Then you tapped the Borkum and Lowestoft cable--I remember the newspaper report stated that it was interrupted." "No, I did not. If anything went wrong with that cable it was merely a coincidence. What would be the use of tapping a cable if by so doing it was made useless for transmitting messages? No, it was the Middlekerke and Dumpton Gap lines we took on board, and consequently heard the whole of the business concerning the _Zietan_, and a considerable amount of other intelligence as well. Now I think you have seen all that there is to be seen for the present," continued Captain Brookes, after the engine-room had been inspected. "There is one more marvel, on which I pride myself not a little, but until the finishing touches are completed it would be better to say nothing about it. Some day, and at no distant date, I hope to enlighten you on that subject."