"We are not at all fed up with your hospitality, Tress," replied Fuller, "only we ought to have been on board the old 'Hippo' long ago. I think, if there's a chance, we ought to get ashore, report to the Commander-in-Chief and await orders." The "Antipas" was steaming at a good twenty knots. It was late in the afternoon; the sea calm, the sky slightly overcast. With a steadily-rising glass the weather showed indication of continuing fine, notwithstanding the presence of patches of sea-fog. Towards sunset the fog increased until it was no longer safe for the destroyer to maintain her speed. Fishing boats, dauntlessly risking the submarine menace, were frequently in these waters. To tear blindfold through the dense mist would be courting disaster. The slowing down of the engines brought the three airmen on deck. "Fog!" exclaimed Kirkwood. "Rough luck. I thought that we were entering port when the skipper rang down for easy ahead." "Pretty thick, too," added Barcroft. "It's as much as I can do to see the bridge. Beastly calm, too; what do you say to returning to our little rubber of dummy?" "Now I'm here I'll stop," decided Fuller, drawing his coat across his chest. "Hullo! they're taking soundings. That looks as if we were nearing shore." For nearly an hour the "Antipas" literally "smelt her way." Darkness had fallen, and with it the fog bank increased in density and dimensions. No longer was it possible to discern anything beyond a couple of yards. No discordant hoot blared from the syren, no navigation lights were shown. Beyond slowing down nothing more could be done, owing to war conditions, to safeguard the destroyer from risks of collision. "Hullo, you fellows!" exclaimed the lieutenant of the destroyer as, clad in oilskins, sou'wester and sea boots, he groped his way for'ard. "Have we made it too comfortable for you down below?" "Didn't know that it was your 'trick,'" remarked Barcroft. "Neither is it. That's one of the penalties of serving on a destroyer. You never know when you're off duty. The skipper's just spoken through: we're on the track of a strafed U-boat. Picked her up by microphone." "Here's to the bridge, then," decided Fuller. "Come on, you would-be card-players. Let's see the fun." "One of the advantages of going dead slow, I suppose," commented Tressidar as his guests rejoined him. "We've cut across the trail of a submarine, that's certain. Come in, and see how things are progressing." The lieutenant-commander opened the door of the chart-room. Against one bulkhead stood the receiver of the submarine-signalling apparatus. Standing in front of it was a bluejacket with both ear-pieces clipped to his ears. With his left hand he was alternately actuating the switch that connects both receivers. "Right dead on, sir," he reported. "Less than a couple of cables' lengths ahead, I'll allow."