. Animal mechanism: a treatise on terrestrial and aërial locomotion. Animal locomotion; Flight. CHANGES IN THP: PLANE OF THE BIRD S WING. 26$ The direction of the movement of the wing is read from above and forward, from H to Av. Fig. Ill shows that the wing during its ascent assumes an inclined position which allows it to cut the air so as to meet with the minimum of resistance ; while in its descent, on the contrary, the position of its plane is reversed, so that its lower surface turns downwards and slightly backwards. It follows, that in its period of depression, the wing, by its obliquity
. Animal mechanism: a treatise on terrestrial and aërial locomotion. Animal locomotion; Flight. CHANGES IN THP: PLANE OF THE BIRD S WING. 26$ The direction of the movement of the wing is read from above and forward, from H to Av. Fig. Ill shows that the wing during its ascent assumes an inclined position which allows it to cut the air so as to meet with the minimum of resistance ; while in its descent, on the contrary, the position of its plane is reversed, so that its lower surface turns downwards and slightly backwards. It follows, that in its period of depression, the wing, by its obliquity, acts upon the resistance of the air, and while raising the body of the bird, carries it forward. We see, also, that. Fig. 111.—Inclinations of the plane of the wing with reference to the axis (Av) of the body during flight. the inclination of the wiug changes gradually, in the different phases of its elevation and of its descent. Especially in this latter phase, the influence of the air in shaping the course of the wing is more evidently seen; it is, in fact, at the moment when the rapidity of its depression attains its maximum that we see the posterior edge of the wing turn up the more strongly. The wing, when it has reached the end of its descending course, changes its plane very suddenly. The explanation of this movement is very natural. As soon as the resistance of the air ceases to raise the feathers, these, by their elasticity, return to their ordinary position, which they occupy during all the phase of elevation. Even the ellipse which forms the trajectory of the wing can. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Marey, Etienne-Jules, 1830-1904. New York, D. Appleton and co.
Size: 1771px × 1412px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1870, booksubjectflight, bookyear1874
