Another great fault of the turbine is that it can only go one way, so that in order to enable a ship to go astern, she has to be fitted with an additional propeller and turbine, the blades in the latter being placed in the opposite way; when the ship is going ahead, these just revolve idly. In practice it is usual to employ two propellers and turbines for going astern instead of one. For driving other than fast ships the turbine was found not to be economical, but the reader may ask the question: “Why not let the ship go fast? Why detain her, if she is anxious to get to port?” The answer is that she wouldn’t get there as fast, for the reason that unless the ship is designed to travel at very high speeds, the propeller, revolving at a great rate, loses its efficiency; for, instead of being able to use the water, much as an oarsman uses the water for his oar to get a good grip, the water is simply carried round with the screw. In order to counteract this failing, therefore, it has been suggested that the turbine should not drive the propeller direct but drive a dynamo, the current from which should actuate electric motors for such a speed as will suit the propellers. With this would also vanish the reversing difficulty, for a motor is easily reversible. But a paper was read by the Hon. C. A. Parsons, the Vice-President, at the annual meeting of the Institution of Naval Architects, in March, 1910, in which he gave particulars of a scheme to enable a high-speed turbine to be suitable for a low-speed tramp steamer. As Mr. Parsons’ theory has actually been put into practice, and will no doubt be found to be the solution of the problem, we may here outline so interesting an experiment. In a word, the method employed is just that which we saw was used in those early days, when the screw engines were first brought in. As the reader will recollect, the difficulty was then overcome by means of gearing, instead of the engines working directly on to the shaft; so, in principle, at least, is it in the present instance.