"It puzzles me," remarked Trehallow to Cavendish as they stood under the lee of the chart-room, the only possible spot on the otherwise exposed bridge where they could converse without having to shout in a howling wind, "it puzzles me to know where these blighters hail from. You can't hide even a disguised cruiser and a submarine in your coat pocket. They must have a base somewhere--but where? There's no port on this part of the coast that isn't under the control and jurisdiction of one or other of the South American republics. It's fishy--very. There's something pretty big behind this. Only the other day----" The appearance of the yeoman of signals, with a signed pad in his hand, interrupted the Lieutenant-Commander's words. "By smoke!" he ejaculated. "Here, Carfax!" The officer thus addressed laid down his telescope and joined his chief behind the chart-house. "Look here, Carfax," continued the Lieutenant-Commander, "what do you make of this?" "This" was a crudely pencilled report, almost obliterated in places where the flying spray had played havoc with indelible pencil. It was to the effect that both seaplanes had been compelled to alight on the surface for the second time in half an hour. On each occasion they had got well to the west'ard of their quarry, hoping to keep in the eyes of the setting sun and thus approach without being observed. They had succeeded in getting within three miles of the fugitive, when unaccountably their engines "konked". "Alighted and made examination," proceeded the report. "Everything O.K. Restarted; came down again. Are now up again. Will----" Here the message ended. "Why didn't the silly owl finish?" inquired Trehallow testily. "'Cause, sir, he's probably had to come down again," hazarded Carfax. "Can't wireless with the aerial trailing in the water and all hands trying to find out what's wrong with the old 'bus. 'Tany rate, we're only fifteen miles astern." "And a stern chase is a long one," commented the Lieutenant-Commander, glancing at a western sky. "Where is the pirate making for, I wonder?" inquired Cavendish, turning to Carfax, when the skipper had gone into the chart-room. "According to what I've heard, he's making for the estuary of the Rio Guaya," replied the Sub of the _Messines_. "Goodness only knows what for. There are three potty little republics somewhere there, and they wouldn't dare to give shelter to a filibustering blighter like that. But what is puzzling me is, why do our seaplanes keep failing? We've had 'em up for eight hours on a stretch many a time and they've never had any trouble up to now. And when they're most wanted they're broken reeds. Give me something that floats, any old time," he added, with sublime youthful confidence in the omnipotence of sea power.