There was a lot to stir the imagination in that sight--aye, fairly to grip you by the throat as a dawning sense of what it portended sank home. In the abstract it was the living, breathing symbol of the relentless progress of America's mighty effort, a tangible sign of the fact that her aid to the Allies would not arrive too late. What it stood for concretely is best expressed in the words of the young R.N.R. sub-lieutenant who was officer of the watch at the time. "It looks to me," he said, with a pleased smile, as he lowered his glass after a long scrutiny of the advancing lines of ships, "as though there'd be jolly near forty thousand new Yanks to be catered for in Liverpool by to-morrow evening." "Yes," I said somewhat dubiously, my mind suddenly assailed by a misgiving awakened by the thousands of yards of torpedo target presented by the sides of those placidly ploughing ships, "that is, assuming that they get there safely. But they're only just entering the danger zone now, and there's a lot of water got to stream under their keels before they berth in the Mersey. "I don't know anything about convoys, or the ways of protecting them; but all the same, it looks to me as though that bunch of troopers would offer a mark like the map of Ireland to a U-boat, and a lot more vulnerable one." Young P---- laughed as he bent, squint-eyed, to take a bearing on a destroyer zigzagging jauntily with high-flung wake in the van of the approaching fleet. "That's what everyone--even an old sailor--says the first time he sights one of the big transatlantic convoys," he said; "and if there are any skippers new to the job in that lot there, that's just what _they're_ saying. It's all through failure to appreciate--indeed, no one who has not seen the ins and outs of it would be in a position to appreciate--the effectiveness of the whole anti-submarine scheme, and, especially, what almost complete protection thoroughly up-to-the-minute screening--with adequate destroyers and other light craft--really affords. As a matter of fact, every soldier in that convoy is probably a good deal safer now--and right on in through this so-called danger zone to harbour--than he was marching down Broadway to the pier--at least, if Broadway is like it was when I used to put in to New York as a kid in the _Baltic_." "But will you tell me," I protested, "how a U-boat, firing two or three torpedoes from, say, just about where we are now, could possibly miss a mark like that?" "Well, it would take a bit of missing from hereabouts, I admit," was the reply; "only, if there is any Fritz still in the game with the nerve to try it, he would also be missing himself." "What would happen to him?" I asked. "One or all of two or three things might happen,----" P---- answered, after ordering a point or two alteration in course to give safe berth to the nearing destroyer.