
them; and by this arrangement nature seems to have saved weight and space, as well as to have obtained the object for which they were more especially intended, that of restraining backward motion, as in the sea-gull, (See Plate 2, <s>Fig:<\s> letters a). And as Dr Roget has observed, of the vane of the feather in the wings of birds “they derive this power of resistance from their flattened shape, which allows them to bend less easily in the direction of their flattened surfaces, than in any other; in the same way, that a slip of card cannot easily be bent by a force acting in its own plane, though it easily yields to one at right angles to it. Now it is exactly in the direction in which they do not bend, that the filaments of the feather have to encounter the resistance and impulse of the air; it is here, that strength has been wanted, and it is here, that strength has been bestowed.” Bridgewater Treatise, Vol. 1.:p. 569. The motion of the spine forwards is prevented by strong flat ligaments, in color very like the ligamentum nuchae, which is situated between each spinous process, and attached to the thin edge of each, the whole of its length. The long flat bones, which I have just des- cribed, exert their influence too, in restraining the forward motion of the spine; and in some birds, as the
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Manuscript details
- Author
- George Oakley Fleming
- Reference
- AP/28/6
- Series
- AP
- Date
- 1846
- IIIF
-
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Cite as
On Motion in the lumbar division of the spine of birds, by George Oakley Fleming , 1846. From The Royal Society, AP/28/6
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