captain’s own job, and we naturally hint a desire that he should pursue the subject. ‘There is no difficulty about it--the Germans already know all that they can ever know of our convoy system--how it is organised in the form of group-sailings on definite routes, and worked, as far as possible, at night, with extra protection given by daylight and during moonlight hours--above all, how successful it is, and how, little by little, they have given up the chase of mercantile convoys for the attack of transports and single ships of great size and value. In one month, for instance, of the present year, 690 vessels were convoyed from England to France, of which only three were attacked, and only two sunk, including one small sailing ship. More astonishing still, out of 693 convoyed from France to England in the same month not one was touched, or even attacked. Then there are the Dutch and Scandinavian lines.’ We should like to know exactly how it is done, and especially what part the destroyers play in the game. Briefly, but very sharply, the picture is drawn for us. You see a fine August day, off the coast of Scotland, with white summer clouds over a rippling sea; a compact convoy of eight ships sailing in two columns, with a ninth lagging on the left, three times her proper distance to the rear. Their speed is slow; they are flanked on both sides, fore and aft, by armed trawlers, with one just ahead of the two columns, and they are covered by two fast destroyers. The first of these is ahead of the convoy, zigzagging continuously from side to side across the whole front. The second is zigzagging in another direction. Suddenly, from this second destroyer, a signal is seen to fly. Her look-out has spotted the wake of a periscope 1000 yards away on her starboard bow, moving to cut off the convoy, from the right column of which it is already not more than 1500 yards distant. A torpedo fired at this moment should cross the convoy formation exactly in the middle, and would have an excellent chance of sinking either of the centre ships in either column--it could hardly miss all four. But the destroyer has in a moment altered course 8 points to starboard, and is prolonging this zigzag directly towards the enemy at thirty-odd knots, with her forward guns blazing. The U-boat captain, no doubt, longs to take his shot into the brown; but he has less than one minute in which to perform the more urgent duty of saving his own ship. Down he goes, with a depth-charge after him, and is not seen or heard of again in this story. The convoy calls up its lame duck and goes safely to its destination. ‘Yes,’ says the Captain, ‘we get them through, and it all looks very simple; but it’s mostly a matter of ten seconds, and you can’t grow fat on a daily margin of ten seconds.’ ‘But the Admiral has something to say on your report?’