I have been waiting eagerly for this invitation and I follow Captain Hodgson from the control-platform, stooping low to avoid the bulge of the tanks. We know that Fleury's gas can lift anything, as the world-famous trials of '89 showed, but its almost indefinite powers of expansion necessitate vast tank room. Even in this thin air the lift-shunts are busy taking out one-third of its normal lift, and still "162" must be checked by an occasional downdraw of the rudder or our flight would become a climb to the stars. Captain Purnall prefers an overlifted to an underlifted ship; but no two captains trim ship alike. "When _I_ take the bridge," says Captain Hodgson, "you'll see me shunt forty per cent. of the lift out of the gas and run her on the upper rudder. With a swoop upwards instead of a swoop downwards, _as_ you say. Either way will do. It's only habit. Watch our dip-dial! Tim fetches her down once every thirty knots as regularly as breathing." So is it shown on the dip-dial. For five or six minutes the arrow creeps from 6,700 to 7,300. There is the faint "szgee" of the rudder, and back slides the arrow to 6,500 on a falling slant of ten or fifteen knots. "In heavy weather you jockey her with the screws as well," says Captain Hodgson, and, unclipping the jointed bar which divides the engine-room from the bare deck, he leads me on to the floor. Here we find Fleury's Paradox of the Bulkheaded Vacuum--which we accept now without thought--literally in full blast. The three engines are H. T. &. T. assisted-vacuo Fleury turbines running from 3,000 to the Limit--that is to say, up to the point when the blades make the air "bell"--cut out a vacuum for themselves precisely as over-driven marine propellers used to do. "162's" Limit is low on account of the small size of her nine screws, which, though handier than the old colloid Thelussons, "bell" sooner. The midships engine, generally used as a reinforce, is not running; so the port and starboard turbine vacuum-chambers draw direct into the return-mains.