If the wing is large, I employ steel tubes, bent to the proper shape. In some cases I secure additional strength by adding to the oblique ribs or stays (_g h i_ of fig. 122) a series of very oblique stays, and another series of cross stays, as shown at _m_ and _a_, _n_, _o_, _p_, _q_ of fig. 123, p. 241.
This form of wing is made to oscillate upon two centres viz. the root and anterior margin, to bring out the peculiar eccentric action of the pinion.
If I wish to produce a very delicate light wing, I do so by selecting a fine tapering elastic reed, as represented at _a b_ of fig. 124.
To this I add successive layers (_i_, _h_, _g_, _f_, _e_) of some flexible material, such as parchment, buckram, tracing cloth, or even paper. As the layers overlap each other, it follows that there are five layers at the anterior margin (_a b_), and only one at the posterior (_c d_). This form of wing is not twisted upon itself structurally, but it twists and untwists, and becomes a true screw during its action.
FIG. 123.--_Artificial Wing with Perpendicular (r s) and Horizontal (t u) Elastic Bands_ attached to ferrule (_w_).
_a_, _b_, Strong elastic reed, which tapers towards the tip of the wing.
_d_, _e_, _f_, _h_, _i_, _j_, _k_, Tapering curved reeds, which run obliquely from the anterior to the posterior margin of the wing, and which radiate towards the tip.
_m_, Similar curved reeds, which run still more obliquely.
_a_, _n_, _o_, _p_, _q_, Tapering curved reeds, which run from the anterior margin of the wing, and at right angles to it. These support the two sets of oblique reeds, and give additional strength to the anterior margin.
_x_, Ball-and-socket joint, by which the root of the wing is attached to the cylinder, as in fig. 122, p. 239.--_Original._]
FIG. 124.--Flexible elastic wing with tapering elastic reed (_a b_) running along anterior margin.
_c_, _d_, Posterior margin of wing. _i_, Portion of wing composed of one layer of flexible material. _h_, Portion of wing composed of two layers. _g_, Portion of wing composed of three layers. _f_, Portion of wing composed of four layers. _e_, Portion of wing composed of five layers. _x_, Ball-and-socket joint at root of wing.--_Original._]