"I also found that when explosions had taken place in the M.L., or when it was heavily afire by the time the U-boat drew near, it was the practice of the latter to come boldly up and finish the good work at leisure, with the addition of any of the inimitable little Hunnisms--such as firing on the boats, or ramming them, or running at full speed back and forth among the wreckage so as to give the screws a good chance to chop up the swimming survivors--of which _Unterseeboot_ skippers were even then becoming past masters. [Illustration: A DEPTH CHARGE] [Illustration: DISABLED DESTROYER IN TOW] "In short," here D---- paused for a moment while he lifted the little electric heater and lighted a fresh cigarette on one of the glowing bars, "in short, I studied the vermin in just the same way I did the gophers and prairie-dogs when I started to exterminate them on my Kansas farm. I found out when they were most likely to come up, when to stay down; what things attracted them, and what repelled. Then I went after them. Of course, there was no chance for the clean sweep I made of the gophers and prairie-dogs, but we've still managed to keep our own little section of the beat pretty clear. "Having satisfied myself regarding the Hun's penchant for stealing up, submerged, to gloat over the dying agonies of his victim, it seemed to me that the obvious thing to do was to lead him on with an imitation death-agony, and then have a proper surprise waiting for him when he came up to gloat. The first thing I started working on was how to 'burn up' and 'blow up' with sufficient realism to deceive the skipper of a submerged U-boat, and still be in shape to spring an effective surprise if he could be tempted into laying himself open to it. "My first plan proved too primitive by far. I reckoned that the 'blowing-up' touch might be provided by dropping a depth-charge, and that of 'burning up' by playing my searchlight on the surface of the water on the side the approach was to be expected from. Neither was good enough. The 'can' might have been set to explode on the surface, but that could not be affected without running the chance of blowing in my own stern. But the bing of a depth-charge detonating well under the water is quite unmistakable, and the first U-boat I tried to lure with one made off forthwith, plainly under the impression that it was the object of an active attack. As for the searchlight, I saw that it wouldn't do the first time I went down and took a peep at a trial of it through the periscope of one of our own submarines. The beam did cast a patch of brightness discernible through the upturned 'eye' at a depth of from sixty to eighty feet, but it was neither red enough nor fluttery enough to suggest anything like a burning ship. I set to work to devise something more life-like, without ever waiting for a chance to draw a Fritz with it.