250 



AERONAUTICS. 



81, p. 157, and fig. 88, p. 166. A continuous movement 

 begets a continuous buoyancy ; and it is quite remarkable to 

 what an extent, wings constructed and applied to the air 

 on the principles explained, elevate and propel — how little 

 power is required, and how little of that power is wasted in 

 slip. 



If the piston, which in the experiment described has been 

 working vertically, be made to work Jwnzontalhjy a series of 

 essentially similar results are obtained. "When the piston 

 is worked horizontally, the anterior and posterior elastic 

 bands require to be of nearly the same strength, whereas 

 the inferior elastic band requires to be much stronger 

 than the superior one, to counteract the very decided ten- 

 dency the wing has to fly upwards. The power also requires 



Fig. 127. 



Fig. 127. — Path described by artificial wave wing from right to left. x,xf, 

 Horizon, m, o, Wave ti-aek traversed by wing from right to left, p, 

 Angle made by the wing with the horizon at beginning of stroke, q. Ditto, 

 made at middle of stroke, h, Ditto, towards end of stroke. c, Wing in 

 the act of reversing ; at this stage the wing makes an angle of 90° with the 

 horizon, and its speed is less than at any other part of its course, d, Wing 

 reversed, and in the act of darting ux) to u, to begin the stroke from left to 

 right {vide u of fig, 128). — Original. _ 



Fig. 128. —Path described by artificial wave wing from left to right, x, xf. 

 Horizon, u, v, w. Wave track traversed by wing from left to right. t, 

 Angle made by the wing with horizon at beginning of stroke, y. Ditto, 

 at middle of stroke, Ditto, towards end of stroke, r. Wing in the act 

 of reversing ; at this stage the wing makes an angle of 90° with the horizon, 

 and its speed is less that at any other part of its course, s, Wing reversed, 

 and in the act of darting up to m, to begin the stroke from right to left [vide 

 m of fig. 127). — Original. 



to be somewhat differently applied. Thus the wing must 

 have a violent impulse communicated to it "when it begins the 

 stroke from right to left, and also when it begins the stroke 

 from left to right (the heavy parts of the spiral line repre- 

 sented at fig. 71, p. 144, indicate the points where the impulse 

 is communicated). The wing is then left to itself, the elastic 

 bands and the reaction of the air doing the remainder of the 

 work. When the wing is forced by the piston from right to 



