is essentially applicable in modern naval warfare when single-ship actions take place at comparatively short range. The days of courteous exchange of compliments between doughty antagonists before opening fire are past. The first shot may decide, and frequently has decided, the contest. Therein, especially during night encounters between destroyers in the Straits of Dover and off the Belgian coast, the Huns held an important advantage. Every vessel afloat was to them an enemy craft, while the British had to withhold their fire until they made certain that they were not attacking a friendly or neutral ship. "She's flying the White Ensign!" exclaimed Macquare. "By Jove, she's been at it!" The approaching submarine turned out to be one of the E Class returning from observation patrol. She was showing a considerable amount of freeboard. Most of her water-ballast had been started. Just abaft her conning-tower, on the port side, a tarpaulin and a "thrum mat" had been lashed over a rent extending from just above her water-line to half-way across her curved deck. Pumps were steadily ejecting water--a circumstance that told of strained plates and shattered rivets. Of her twin periscopes, one had been shorn off close to the top of the conning-tower; the other, bent at an acute angle, trailed drunkenly over the side. Dive she could not, unless once and for all time. Only by running on the surface and keeping the leaks under control could she hope to make port. With her ensign proudly displayed, and most of her officers and crew drawn up on her narrow deck, she held on her course, the passing submarines saluting each other according to the honourable and long-standing custom of the seas. The Hon. Derek Stockdale raised a megaphone to his lips. "Been strafed?" he enquired laconically. "Aye, aye," was the reply, shouted in clear, decisive tones. "Scrapped with a Zepp., crocked her, and then took on a U-boat. She won't trouble you, but keep your weather eye lifting for Zepps. S'long and good luck!" Ten minutes later the E Something was out of sight. Her cruise had been honourably accomplished. She was bound for home and a well-earned rest. R19's had just begun, and already the prospect of imminent excitement was in store. Dark, rugged clouds, scudding rapidly in the upper air, betokened a gale as surely as did the steadily-falling mercury of the barometer. With luck R19 ought to overhaul the crippled Zepp. as she strove to battle her way against the rising storm. CHAPTER VI The Zeppelin Hunt Before long the wind rose, blowing strongly from the nor'west. In less than an hour it had increased to half a gale and had veered due east. Vicious white-crested waves were slapping against R19's snub bows and surging in green cascades as far as the base of the conning-tower.