Slim as the chance was, the captain was reluctant to leave while any hope remained, and it was only a signal ordering the _Flash_ to join in some other work that had turned up (a destroyer is subject to as many kinds of summons as a country doctor) that took him off in the end. Mooring a buoy to mark the spot for "future reference," the captain saw her headed off on the course she was to hold till daybreak, and then took me down to the Chart House for a bowl of ship's cocoa before turning in. It was some question I asked about the practice of placing buoys over possible U-boat graveyards, to make it easy to resume investigations if desired, that started him on a train of anti-submarine reminiscence that led back to one of the smartest achievements of its kind in the whole course of the sea war. "There are times," he said, leaning back on the narrow couch that served as his "sea-bed," and bracing with outstretched legs against the twisting roll, "that a Fritz will do things that would lead a superficial observer to think that he had a sense of humour. Of course, we know that he hasn't anything of the kind (any more than he has honour, sportsmanship, decency, or any other of the attributes of a normal civilised human being). But the illusion is there just the same, especially when he tries on such little stunts as the one he incubated a couple of months ago in connection with a buoy I dropped to mark the spot where there was a chance that my depth-charges might have sent him to the bottom. "It was just about such an 'indeterminate' sort of a strafe as the one we've just had--no chance for gun-fire, not much to go by for planting depth-charges, and, in the end, nothing definite to indicate that any good has been done. So, in case it was decided that my report was of a nature to justify further looking into, I left a securely moored buoy to furnish a guide as to where to begin, quite as we have to-night. Well, it chanced that the S.N.O. at Base reckoned that there was just enough of a hope to warrant following up. Indeed, you may be sure there isn't much that isn't followed up these days, now that we've got our whole comprehensive plan into operation and adequate craft to support it with. So he sent out quite a little fleet of us--craft fitted to do all the various little odds and ends of things that help to make sure one way or the other what has really happened to Fritz. Luckily, _Flash_ was able to return with them. If she had not--if someone who had not seen the lay of things after the strafe the night before had not been along to 'draw comparisons'--Fritz's little joke might have turned out a good deal more pointed than it did.