LOCOMOTION OF ANIMALS. 



LOCOMOTION OF ANIMALS. 



60t 



(dilating, and the figure is consequently an illustration of very slow 

 walking, agreeably to what ha* been already mentioned. It should 

 alto be remarked that 6, the period of twinging, is the middle of the 



paoe -, 4, , which together constitute a single step. la Jig. 15 an 



outline of the human skeleton is represented in twelve positions as 

 iVnigned by Professor Weber, on a scale of one-tenth the natural size 

 of man. The simultaneous relative positions of the head, trunk, and 

 legs an piesenedjtt each of these twelve instants, as viewed through 

 a revolving optical instrument like a stroboacope, which has been 

 adapted for this purpose by Stampfer. By means of this instrument 

 the consecutive positions of the trunk and legs may be taken at very 

 minute intervals of time, a subject of great importance to the sculptor 



described. This excellent figure is necessarily complicated owing to 

 the number of positions depicted, but it is easily understood if studied 

 with the attention it deserves. 



In very slow walking the centre of gravity is borne along in a more 

 elevated position than in quick walking ; indeed, whatever tends to 

 elevate the centre of gravity tends also to decrease the velocity of 

 walking ; for the length of the hindmost leg, which is nearly the same 

 in all paces, is equal to the square root of the sum of the squares of 

 the height of the centra of gravity from the ground, and of the length 

 of the step ; and consequently, the shorter the step the greater is the 

 height of that centre, and vice versa. This is observable in corpulent 

 persons, and in porters bearing burdens on the head and shoulders 

 the scientific law being thus confirmed by experience. 



and painter of animals, but which under ordinary circumstance! 

 could not be accomplished. In fg. 15 the numbers 1, 2, 3 show the 

 right leg on the ground, and the left log swinging in advance of it, 

 pint before it reach?* the earth at the end of the step seen at number 4. 

 The number* 6, 6, and 7, which are omitted to prevent coiifunion, are 

 the successive positions of the two Irgs resting on the ground before 

 UM next stop commence* with raising the right leg : during thix pi-riod 

 the centre of gravity move* forward, and the right leg when raised is 

 a* it wr left behind, and i* found in the position of number 8. 

 Numbers 9, 10, and 1 1 show the successive positions of the right leg 

 winging behind the left; and 12, 13, 14 iU positions when it overtakes 

 and ftmn the left leg, until it reaches the last position, number 15, 

 correspond* with the number 1 of the other leg, a* above 



ind pass** 

 .hicTcor. 



In slowest walking, the swinging leg passes through a less curve 

 than in quick walking, la fig. 16 we observe the leg is placed on the 

 ground in advance of the vertical line passing through the head of the 

 thigh-bone ; and as a vertical line passing through the centra of gravity 

 falls behind the bane of support, the posterior leg cannot be lifted 

 from the ground until the swinging leg has partially swung back again 

 into a vertical position. During this period, both legs being on the 

 ground, the time of the step is a maximum, because the duration of 

 a step consists of the time employed by the swinging leg in describing 

 its curve, and the time wherein both legs are on the ground, both 

 which quantities increase as the velocity diminishes. In this case the 

 straight lines, a, fig. 14, have the greatest relative length with respect 

 to the curved lines, 6. 



