20 Aerial JYavigation. 



while those beyond open, and let the incumbent air through. Both 

 wings being fastened together moveably by the hinges at 5, t, u, v ; 

 when the handles are raised up, the axles advance towards the car, 

 and when brought down from it, to allow their motion by means of 

 the joints \i, li, in the semi-circular rods G^, Gg. The aeronaut, 

 in moving wings on this plan, has a purchase of one half of each 

 wing to strike the air beyond the axles, and his own weight suspend- 

 ed on the other, the air within, besides the alternate reaction, arising 

 from their percussion, which is proportional to the power applied on 

 each side of the axles EE, ee. Whether the handles are moved 

 upwards or downwards, the wings strike the air equally and con- 

 stantly on each side of the car, and alternately on each side of 

 their axles, during their motion, and the reaction of the air assists 

 so as to move them equally and constantly. The wings being bal- 

 anced on their axles and the valves nearly so on their wires, it is evi- 

 dent that their weight is no impediment to their motion. Wings of 

 any shape and size, being wired, valved, and balanced equally on 

 each side of their axles, can be governed and moved by a small 

 power or force, and the better and the more effectually as the power 

 or force is increased. This principle of a balance can be likewise 

 beneficially applied in submarine navigation, either to ascend, de- 

 scend, or move forward in the water. In figure 2, when the aero- 

 naut raises the hoop efgh, quickly, all the valves between it, and the 

 middles of the flattened shafts I, J, K, L, M, N, O, P, or where the 

 upper ends of the braces 1,2, 3, 4, 5, 6, 7, 8, are moveably hung to 

 them, will open and let the incumbent air through ; while those be- 

 yond will close, air tight, and strike the air proportionally to the quick- 

 ness of the motion; when he brings the hoop quickly down, all the 

 valves between it and the middle of the flattened shafts will close air 

 tight and strike the air similarly ; while those beyond will open and 

 Jet the incumbent air through. When the hoop is raised, (as all the 

 flattened shafts are moveably hung to it,) the upper ends of all the 

 braces, (being likewise moveably hung at both ends,) move inwards 

 towards the car, while when it is brought down, they move outwards and 

 thus -allow the motion of a balance to the whole surface of the wing or 

 wings. The percussion being equal all around the car, there is properly 

 but one wing on this construction. This wing strikes the air equally 

 all around the car, at equal distances, when moved and prevents the' 

 escape of the air at any part within its circumference.. Having de- 

 scribed two applications of the principle of a balance to the motion 



