The "flexibility" of the Grand Fleet, in spite of its increasing size--it has seldom if ever gone to sea but what it was stronger by many thousands of tons than when it last emerged--is a source of never-ending wonder to one to whom it has not become a commonplace by endless repetition, and the swiftness and ease with which it changes form at the will of the Commander-in-Chief never fails to remind me of one of those fascinating wire toys which an ingenious child can push or pull into a great variety of geometrical shapes. A few points' alteration of course changes a squadron--or a half dozen of them steaming abreast--into any desired "Line of Bearing," which might be what would happen in case it was deemed advisable to start zigzagging to avoid a submarine. A squadron may go from "Line Ahead" to "Line Abreast" in anywhere from a few seconds to a few minutes, according to the course the latter is going to hold, and so on through other formations, simple and complex. How this works in practice I had a good opportunity to see before we returned to Base. The general practice on a "P.Z." for the Grand Fleet is to make a comprehensive sweep around the North Sea for two or three or four days, and then--if none of the enemy has been caught up in the net--to chivy together as large a force as possible of battle cruisers, light cruisers, and anything else available and have a sham fight with them. Failing in the former on this occasion, recourse had been had to the latter, and our Squadron was just getting ready to "open" on some dusky, mist-masked shapes suspected of being the "enemy," when the incident occurred to which I have referred. "To 'equalise' the opposing forces," Admiral Sturdee was explaining to me, "it is laid down that each ship in the Fleet we are meeting shall represent a Squadron of the enemy. For instance, that light cruiser to the right--the one making all that smoke--represents an 'enemy' Battleship Squadron, which, incidentally, is steaming hard in the hope of getting in a position to waft us a breeze on a 'windy corner' when we begin to turn. Incidentally"--and the lines of his firm mouth relaxed in a quick smile--"I think we shall have turned before he gets to the place he's driving for. Now that ship there (I think she's a battle cruiser) represents----" Just then his Flag Lieutenant, stepping rather more quickly than usual, handed him a signal. "Now fancy that," he said, after running his eye over the laconic message; "there's an enemy submarine ahead of us." "And what might she represent, sir?" I asked, my mind still engrossed with the intricate strategy of the "battle" into which we were rushing at twenty knots an hour. The Admiral had turned to read a second signal--this one from the Flagship--after which he was busy giving some orders on his own account. My very natural query would have remained unanswered had it not been overheard by the Commander, who had just come up from below.