Some way ahead of us rose and fell the dark outlines of the two other Handley-Pages, and we could notice that curious optical delusion of the air, the apparently slow revolution of their propellers, blade after blade appearing to go round in a jerky fashion, though in reality they were whirling invisibly at a speed of 1600 revolutions a minute, or even more. The only explanation of this spectacle, which can often be seen by an airman, is that the vibrations of his machine affect his eyes like the rapid shutters of a cinema camera, and he has continual momentary glances of the propeller in a fixed position. Soon we were abreast of Ostend, and we could see the inland lake of its Bassin de Chasse lying beyond the edge of the coast. We passed Ostend, and far ahead of me to my right I could see the curve of the Zeebrugge Mole, very small and dim in the distant haze. I scanned the sea with my eyes, looking in vain for submarines or destroyers or seaplanes. No mark of any kind broke the shining surface of the water. Now and then a triplane or a "D.H._{4}," flying on some coastwise expedition, slid up to us and dived down past us, or flew a hundred feet above our heads, showing its distinguishing letters and its red, white, and blue cockade. The pilot sat beside me, his huge body almost half out of the machine, his aquiline nose and pronounced chin driving firmly through the rush of the wind, which flapped and fluttered our silk caps; the sunlight shone with the pale gold of spring across our shoulders and arms, and though I was ten miles out to sea in a land machine off an enemy shore, I felt curiously safe, curiously unafraid. The sea seemed to be a safeguard. Little did I know that I was passing over the scene of my midnight tragedy a year later, when I was to regard the sea in a different aspect--when I was to learn by a bitter lesson its pitiless power. The machines in front of us swung round to return. We swung round too, to give ourselves a chance of gaining height before we were passed. This was not needed, for to our amusement we saw that whereas, as was only natural, the other machines had flown up the coast with their nose well in air, climbing steadily, now they were returning homewards with their noses well down, getting out of the danger zone (and it _was_ a danger zone for a slow cumbersome Handley-Page) as quickly as possible. They passed nearly a thousand feet beneath us, and this time we followed them easily. When we were almost abreast of the Nieuport piers once more I suddenly saw a little puff of hard black smoke appear in the air in front of us. Its clean-cut outlines grew less distinct and more hazy as it spread and grew thinner. Another puff appeared near it and a little above it, and in turn began to enlarge and dissipate. "Why! They're shelling us!" exclaimed my pilot. I looked below. There lay the two destroyers steaming slowly in circles.