Aerial J^avigation. 21 



of wings, to give it an easier illustration, let a stiff, thin board, two feet 

 wide, and ten long, be perfectly balanced and moveably hung to the 

 sharp edge of another, let a handle be attached to one of its extreme 

 ends to move it. Now the fluid or air in which it is, being of a uniform 

 density, it is evident that the least possible power or force that can 

 be applied to this handle, either upwards or downwards, will move it 

 notwithstanding its size and weight. If this board were valved and 

 moved or balanced swiftly its percussion would grow more power- 

 ful by the alternate and constant reaction of the air on its under sides. 

 Having described the manner of constructing, hanging and moving 

 wings upon a principle which will render their motion easy and almost 

 independent of weight, shape, or size ; and percussion powerful and 

 constant ; I shall now proceed to illustrate the manner of suspending 

 or fastening the wings to a balloon, filled with rarefied or inflammable 

 air, whose ascensive power must be nearly sufficient to overcome or 

 balance all the gravity or weight of the whole apparatus, including the 

 balloon, net-like envelope, pilot car, passenger or observer car, pilot, 

 passengers or observers, ballast, and all other things intended to be 

 carried or conveyed. It is evident from observation, that a vessel or 

 body that will move with the least resistance in any one fluid, will 

 move equally well in another, in proportion to their density, if that 

 only is variable. Therefore vessels or bodies that move with the 

 least resistance in water, will likewise move the easiest in the air, the 

 water being only a fluid of considerably greater density than air. 

 The shape of the balloon should, therefore, be oval or basi-conical, 

 or that of two cones joined together at their bases, or partly resem- 

 ble the hulk of the vessel to insure progression. A balloon being 

 made of a sufficient size, of the shape or form of the least resistance 

 to progression, and filled with rarefied or inflammable air, so as to 

 balance, by its ascensive power, nearly all the weight intended to be 

 carried is to be surrounded by a net-like envelope of small cords, so 

 as to cover about four fifths of its whole surface, while the remain- 

 ing fifth, uncovered, is to be on its under side. The wings repre- 

 sented in figure 1, are to be hung or fastened about five or six feet 

 below the balloon, by their axles EE, ee, being attached longitudi- 

 nally to the ends of the cords of the net-like or reticulated envelope ; 

 and at equal distances. The wing or wings, represented in figure 2, 

 are to be suspended at the same distance below the balloon, by means 

 of the ends of the cords of the envelope, being fastened at the 

 middles of the flattened shafts 1, J, K, L, M, N, O, P, in equal num- 

 bers and at equal distances, all around the car SS. 



