These sounds eventually developed into a perfect nightmare. Every swish and creak seemed to pierce our brains. Eventually we climbed up into the seats again for a while and stared our eyes out scanning the horizon with our powerful glasses. Every piece of flotsam seen we dubbed a boat, till it drifted near enough to make out detail. The wind got up a little and died down again, but it shifted the haze somewhat. In the afternoon we saw a sight which gladdened our hearts. High up to the nor'-west, and dropping towards us, was a bird-like machine. Nearer and nearer it came, till we could hear the engines clearly. Soon we identified her marks, which set our fears at rest. It was a British 'plane. We sprang up, gesticulated wildly, and fired a few pistol-shots just to relieve our excitement. She was a rescue seaplane from our own base, it appeared, and presently she dropped on the water beside us and "taxied" as close as she might. Her pilot steered within twenty yards or so of us, and the observer heaved overboard in our direction a huge vacuum flask. Then, without stopping their engine, and waving cheerily, they droned along the surface and tilted into the air again. We watched her until the machine became a mere speck and finally faded into the blue. Then, and not till then, we remembered the flask. We were fated never to taste its contents, however, for it floated past out of reach, in the midst of a great school of giant jellyfish. I have never been stung by one of these loathsome-looking creatures, and I had no desire to be on this occasion. Neither had the pilot, so the bottle floated out of sight without giving us anything but moral support. After this interlude our long impatient wait recommenced. The episode had instilled hope into us, but the hours seemed to drag more heavily than ever. There was nothing but sea on every hand--a great circular expanse of glaring, shimmering water. Presently schools of porpoises began to put in an appearance, sporting about in their own unmistakable style. There must have been hundreds of them. One group frolicked close around us, and several times a glossy black tail caught one or other of the floats a resounding smack. The fabric of these floats is exceedingly frail, and we were rather concerned about them. It seemed a pity to shoot the playful creatures, particularly as their antics created a diversion, but we trembled for the safety of the floats every time they were struck. As the tide went down, several dark, spheroidal objects commenced bobbing up by twos to the surface--on our starboard beam, as we were floating at that time. Through our glasses we could spot scores more of them in the distance. No need to tell one another what they were. We _knew_--deadly contact mines! The nearest pair were only a matter of half a cable's length away, and presently our worst ordeal commenced.