"If there is any risk, I'd rather you wouldn't take it, sir," urged the sailor. "Thank you, but I'll stand by. Swing the axe," ordered Dave. A few blows knocked in the panelling, revealing, beyond, a room of considerable size. Into this stepped the two officers, followed by the seamen with them. Unlike any part of the ship they had previously seen, this place was lighted by electricity. Burton found the switch, and turning it on, let in a flood of light. "Sir, did you ever!" gasped the ensign. The purpose of this room was all too plain. It was fitted with compressors, leading to a tube that left the ship under water. A small but powerful crane was in place over a closed hatchway. The latter, when opened, was found to lead down into a second hold, also electrically lighted. The two officers explored this second hold. "Mines were kept here," Dave nodded, "and were hoisted above as needed. They were dropped astern by means of a compressed air apparatus which, when the mine tube was open, kept the sea from entering. This ugly looking little steamer, outwardly a wood pulp carrier, is really a very capable mine-layer. She has been busy, too, on this cruise to England, but had sown all her mines before we overhauled her." "It's plain enough, sir," agreed Ensign Burton. "Confound this rascally skipper!" blazed Darrin, wrathfully. "While naval craft have been searching everywhere for submarine mine-layers, this skipper has been sailing openly on the seas and sowing mines right under the eyes of our allies! The accursed power of gold! This skipper, his mate and crew have been selling their very souls to the Hun for a bit of his miserable money!" "They won't do it again, sir!" uttered Burton, grimly. "Mr. Burton, you will remain aboard as prize officer, and take the 'Olga' into the nearest British port and turn her over to the British Admiralty authorities. On receiving competent orders you will rejoin." "Very good, sir." "And now we'll hurry above and try to get hold of this ship's papers before any rascal has a chance to destroy them." Boatswain's Mate Runkle had kept the officers and crew of the "Olga" under such close guard that they were unable to get at their papers, which were quickly found by Darrin in the cabin to which he had first been invited on boarding the "Olga." Out on deck, herded forward, were master and mate, seamen, engineers and stokers, a motley-looking outfit of twenty-one men all told. "Bring that fellow here," Dave directed, coming on deck after having examined the ship's papers and then turning them over to Ensign Burton. The master, purple-faced and ugly-looking, his eyes cast down, was brought before Darrin. "Well, sir," announced Dave Darrin, eyeing the man grimly, "we have seen the cargo you have on board, and we have been able to judge the character of the cargo that you have dropped overboard." The skipper started, but did not make any reply in words.