Aerial Navigation. 23 



Having explained my theory of aerial navigation, I will now endeav- 

 or to illustrate its princples more clearly by an example. Suppose an 

 oval balloon, thirty feet long and twenty two feet high or wide, was 

 filled with the lightest inflammable air, so as to raise four hundred 

 and twenty pounds, independently of the weight of itself, net-like en- 

 velope, pilot and passenger cars, and wings, as represented in figure 

 2, sixteen feet in diameter. Two men enter the passenger car, both 

 weighing two hundred and eighty pounds, and one the pilot car weigh- 

 ing one hundred and forty, making in all four hundred and twenty. 

 Now it is evident that the ascensive power exactly balances or equals 

 that of gravity and that the smallest weight added to either, will give 

 it the ascendency or the least percussion of the wings, and consequent- 

 ly reaction of the air, will cause the whole to ascend till equilibrated 

 in the air. Now both being in equilibrium, suppose- twenty pounds of 

 ballast, (as any number can be added that can be raised with ease 

 by the percussion of the wings,) to be put in the passenger car, which 

 will give to gravity so much the ascendency. In order to descend, 

 vertically, in a calm atmosphere, the pilot, standing upright in 

 the center of his car, must, by the wings, strike the air, with suf- 

 ficient force to raise the twenty pounds. Having ascended sufl5- 

 ciently to descend vertically, the pilot has only to cease moving the 

 wings, and the gravity of the twenty pounds will bring the whole ves- 

 sel or machine down. If he wishes to descend slowly, he must keep 

 the handles of the wings raised, and all the air under them will have 

 to pass through the space he occupies at their center, while, if fast, 

 the handles must be held down and all the air under them will rush 

 out at their sides, as the valves of the wings on each side of the 

 axles, all close air tight, in descent. 



Having now shown the manner of vertical ascent and descent, I 

 will explain the manner of progression. There are four ways of dri- 

 ving or impelling this vessel or machine through the air ; by gravity, 

 oblique percussion, the wind, and percussion from vertical wings, and 

 three kinds of progression, ascensive, descensive and direct. The 

 balloon being elevated as far as required to reach any place ; the pi- 

 lot, in order to impel it there, must stop moving the wings and step a 

 litde from the center of his car or line of gravity toward it, which will 

 cause the v/ings to incline, while the twenty pounds will impel it for- 

 ward, as it were, down an inclined plain to the intended place. The 

 faster it is required to move forward, the inclination must be the greater. 

 This is descensive progression. Having descended, the pilot, to reach 



