24 Aérial Navigation. 
any place by ascensive progression, must step a little from the cen- 
ter of his car or line of gravity towards it, which will incline the wings 
that way ; and powerfully move them, which will strike the air oblique- 
ly, and drive the vessel along nearly in the same manner as birds im- 
pel their bodies, whose wings insure both progression and elevation 
at the same stroke. Direct progression is when the vessel moves or 
is impelled forward in a straight line either by the wind or the percus- 
sion of vertical wings. When-the wind blows or moves forward to 
any place which it is intended to reach, it will impel the vessel to it 
without any exertion, more than to keep sufficiently elevated to pre- 
vent striking, and when the balloon has arrived, it can be stopped, by 
dropping the small anchor from the passenger car and winding up its 
cord around the windlass. The vertical wings are to be attached, one 
on each side of the pilot car, above the other wings, but to their axles, 
each being about two feet wide and eight feet long, and similarly wir- 
ed, valved and balanced; but hung at right angles to the horizontal 
wings ; each wing to tats a handle at both ends, and their handles, 
when moved, must be impelled backwards and forwards, instead of up- 
wards and downwards as they can be turned quite around so as to an- 
swer any course ; they are to be moved only while the others are at 
rest. Perhaps a rudder wing of a small size, attached on the under 
side of the passenger car, nearly balanced, hung vertically but not 
valved, would help considerably to determine the motions of the bal- 
loon, and keep them regular. 
Having now given a description of what appear to me to be the 
true principles of aérial navigation, and the manner of application to 
practice, I will offer a few reasons in farther illustration and sup 
of the balancing principle, in the motion of wings, hanging theie 
valves, and governing the ascensive and gravitating powers. Wings 
of a very large size, hung on the balancing principle, perhaps, may 
be moved by steam, the elasticity of condensed air or a lever. 
The more powerful the percussion, the reaction will be greater and 
the elevation quicker. In motion and effect they will nearly resem- 
ble bird’s wings, be proportionally reactive when struck, and be less 
impeded in motion by their weight. The balance valves in their 
motion and effect in the air, will resemble, very neatly the large feath- 
ers of bird’s wings; they ought not to be more than two or three 
inches wide and the others narrower. Now it is evident, that the 
ascensive and gravitating powers, can be balanced or nearly so, as 
well as the wings and their valves; and if balanced, the least addi- 
