Aérial Navigation. 17 
deal less resistance than depressed. V represents a valve, which is 
along, thin, narrow, and light strip or slip of pasteboard, stiffened 
cloth, tin or metal, a little wider than to cover one interstice between 
the wires that run parallel to the axle EE so as to overlap, and as 
long as DD or EE. The side of the valve V, m, n, 0, is to be 
moveably attached or fastened to the wire m, n, 0, on the under side 
of the frame, so as to open about thirty or forty degrees downwards, 
and then shut. The cross wires, parallel to AA and CC, are designed. 
to prevent its striking through, as well as its overlapping a little the 
side DD. The valve V being hung, another valve of the same size 
and shape is to be moveably fastened by one of its longest sides, to 
the next wire towards the axle EE; and another to the next and 
so on till valves are moveably fastened to all the parallel wires, be- 
tween the side of the frame DD and its axle EE. The valves are 
to Jap on the sides of the frame a little and overlap one another 
sufficiently to be air tight. The valves being all moveably hung be- 
tween the side of the frame DD and its axle EE by one of their 
longest sides to the wires, are to be restrained from opening any far- 
ther than is required, by small strings or cords being fastened to their 
other longest sides, and then attached to the side DD of the frame. 
The valves, being all moveably hung and restrained between DD and 
EE, the other half of the frame-of the wing is to be similarly valved 
and have the valves restrained by small strings or cords to the side of 
the frame BFB. The hanging of the valves must commence at the 
side BFB and continue to the axle EE. aa, 6f6, ce, and dd repre- 
sent another similar frame, similarly wired and valved; ee, its axle 
or pivot. W represents a balance valve, gr, its balancing wire; when 
the frame is to be hung with this kind of valves, it is to be wired only 
parallel to its axle. The valves are to be attached on the under side 
of the wings to the wires, so as nearly to balance; their greater part 
must hang down and be similarly restrained as the others; when they 
shut, they must overlap a little and the materials of which they are 
made must be pretty stiff. These two similar frames are to be hung or 
fastened together at stv, by hinges, susceptible of a motion upwards 
and downwards. Gg and Gg represent strong semi-circular rods, 
whose ends are attached or fastened to the under side of the axles 
EE, ee, at HH and hh, by hinges or small staples, so as to allow the 
axles a balancing motion. _I, #, I; i represent four j joints in these semi- 
circular rods, designed, when the sides of the wings BFB and fb 
are raised, as they are attached br hinge at 8, ty Uy B, to admit the 
Vou. XXV.—No. 1. 
