File:Animal mechanism- a treatise on terrestrial and aërial locomotion (1874) (18010406600).jpg

Title: Animal mechanism: a treatise on terrestrial and aërial locomotion
Identifier: animalmechanis00mare (find matches)
Year: 1874 (1870s)
Authors: Marey, Etienne-Jules, 1830-1904
Subjects: Animal locomotion; Flight
Publisher: New York, D. Appleton and co.
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Biodiversity Heritage Library

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342 ANIMAL MECHANISM. at almost every flight of the bird, we succeeded in obtaining, satisfactory results. During the whole of the bird's flight the registering lever described a kind of ellipse. This ellipse, registered on a plate having an advancing movement from right to left, gave figure 100. In order to under- stand this figure, we must imagine the bird flying from left to right (as the tracing is to be read), and rubbing the extremity of its left wing against a wall blackened with smoke; the tracing which its wing would leave under these conditions would be identical with that represented in fig. 100. This curve is a kind of ellipse spread out by the advancing mo- tion of the plate which receives the tracing. Except some trem- blings of the line, which arose from the imperfection of thei apparatus, the trajectory of the bird's wing may be compared to the tracing given under the same conditions by a Wheatstone's rod, tuned in unison, and giving an elliptical vibration. Fig. 101 represents a tracing of this kind. Th e determination of the course of the wing, with the difierent phases of its velocity, is so im- portant, that we resolved to verify by various methods the reality of this elliptical form. All our ex- periments have furnished results which agree with each other; they have shown that birds of dif- ferent species describe with their wings an elliptical trajectory.
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