18 Aérial Navigation. 
axles EE, ee, advancing towards, and receding from each other 
equally. JJ and jj represent two strong rods which connect, or are 
fastened to the two strong semi-circular rods Gg, Gg, at equal dis- 
tances from their center. L represents the car which is firmly fas- 
tened to the rods JJ, jj, at their center. Ef represent the space be- 
tween the wings, which the aéronaut or their mover occupies, who 
is to stand upright in the car and take hold of the handles of the 
wings, K, &, or the middle of their sides BF'B, fb, on each side of 
him, when he wishes to move them. Having now illustrated one ap- 
plication of the principle of a balance to the motion of wings, and 
the manner of constructing them, I shall now proceed to illustrate 
another, on the best possible construction, before I explain how they 
are moved. 2 : 
Figure 2. 
ees ey vr G. 
_ Figure 2.—I, J, K, L, M, N, O, P represent strong flattened shafts. 
The circular jagged line, EFGH, represents a strong spiral wire, 
which is to be fastened to the circumferential ends of all the fattened 
shafts. efgh represent a light, strong hoop to which the other ends 
of the flattened shafts are to be firmly connected by hinges or small 
staples so as to admit of motion upwards and downwards; its size 
