Page:My Airships.djvu/160

 a straight horizontal course (as in Fig. 8) I should desire to rise. I would have but to pull in the guide rope shifter. It would pull the guide rope itself back (Fig. 9), and thus shift back the centre of gravity of the whole system that much. The stem of the air-ship would rise (as in Fig. 9), and, consequently, my propeller force would push me up along the new diagonal line. The rudder was fixed at the stern as usual, and water-ballast cylinders, accessory shifting weights, petroleum reservoir, and the other parts of the machinery, were disposed in the new keel, well balanced. For the first time in these experiments, as well as the first time in aeronautics, I used liquid ballast. Two brass reservoirs, very thin,