It is now possible to describe, as a completed craft, the Wright power-driven plane; Fig. 34 shows its appearance; and in looking at it one is struck by the fact that, save for one or two modifications, and the fitting of motor and propellers, the machine is practically a glider, such as the Wrights used for soaring tests. Of the changes to be observed, the most interesting concern the elevator and rear-rudder. The former, it will be seen, has a double plane; it is, in fact, a smaller biplane on the principle of the main-planes. Needing to increase the surface of the elevator, the brothers fixed one plane above another so as to make the construction stronger and occupy less space. The rear-rudder, acting like that of a ship, worked upon the system described in Fig. 14. With this, as with the elevator, in order to economise space and obtain rigidity, two narrow planes were fitted side by side. So now the practical aircraft stood complete--each part adapted and perfected; and, having traced its development step by step, we see how the pioneers had helped the Wrights to their conquest. Sustaining planes, propellers, controlling surfaces--all had been foreshadowed, all hinted at and sketched crudely; but what had been lacking was the skill which should put these theories into shape; and this skill, and also this patience, Wilbur and Orville Wright provided to the full. Having discussed the construction of the machine, the method by which it was controlled when in the air may be described. In Fig. 35 the operator is seen in the driving seat; and near him will be observed the motor which drives the craft. In his left hand--that is to say in the one nearest us--he grasps the lever which operates the elevating planes. The rod from lever to plane can be seen, and the motions the pilot makes are these: should he wish to rise, he draws the lever towards him and tilts up the elevating planes in the manner already described, increasing the lifting power of the main-planes and so causing the machine to ascend; by a reverse movement of the lever--by pushing it away from him, that is to say--he makes the craft glide downward. [Illustration: FIG. 35.--Driving seat of Wright Biplane. A. Motor; B. Lever operating elevating planes; C. Lever working rudder and wing-warp.]