. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. MOTION. 475 Fig. a many of the small insects leap a greater dis- tance in proportion to their masses than the larger animals; for example, if the Flea, which can leap two hundred times its own height, were as large as the Cricket, it could only leap as far as it does at present; but the latter can leap much higher than the former, and there- fore, of these two insects, the Cricket is the best organized for leaping. We shall now pro- ceed to investigate the effect of the extension of the legs of insects in leaping.
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. MOTION. 475 Fig. a many of the small insects leap a greater dis- tance in proportion to their masses than the larger animals; for example, if the Flea, which can leap two hundred times its own height, were as large as the Cricket, it could only leap as far as it does at present; but the latter can leap much higher than the former, and there- fore, of these two insects, the Cricket is the best organized for leaping. We shall now pro- ceed to investigate the effect of the extension of the legs of insects in leaping. and the muscular force equals \ /, during the time t' of its spiing, .•.4s=^t'3 . (36) and, The velocity of the cat will be, r = JWs hence, that of the tiger is, (37) r' — ^1 — 4s — t/2/s 4 that is, the tiger and cat have the same velocity, and therefore the same height of spring, reckoned from the positions of their centres of gravity at the instant of their quitting the ground. Let / g (Jig. 267) be the axis of the body, passing through the centre of gravity o; a b, the tarsus; b c, the leg; c d, the thigh, with the troehanter; and d e, the hip. All these articulations being flexed, the tarsal extremity b of the leg is advanced forwards under the centre of gravity o, which is a little above it. In this state, if the tarsus a b, which is di- rected backwards, become flexed, the angle a b c opens, and as the tarsus rests against the ground, the leg b c begins to move, and raising its crural extremity, draws with it the whole body. Now, as the centre of gravity is placed before the point b, instead of being elevated, it is, on the contrary, urged forwards and downwards, describing an arc of a circle, of which the centre is b, and the action of the flexor muscle of the tarsus continuing during the whole time that the limb is resting against the ground, the direction of the motion which it impresses on the centre of gravity changes at each point of the arc which the latte
Size: 1269px × 1968px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, booksubjectanatomy, booksubjectphysiology, booksubjectzoology
