12i ANIMAL MECIIAMSM. 



each instant. T5ut we know tliat these shocks are very un- 

 favourable, to the full utilization of mechanical force; we have 

 explained (page 49) the inconvenience which would arise 

 from them in the work of living motive agents, and the 

 manner in which these shocks are lessened by the elasticity 

 of muscular fibre. 



Under the conditions in which a man dragging a load is 

 placed, if he is attached by a rigid strap to the mass which 

 lie has to draw, the shocks of which we have spoken will be 

 produced, and he will feel their reaction on his shoulders. In 

 order to avoid these painful jerks, and to utilize more fully 

 the effort which he makes, we have placed between the car- 

 riage and the traction strap an intermediate elastic portion, 

 the effect of which has answered our expectations. 



We are endeavouring to construct analogous contrivances, 

 which may be adapted to the traces of ordinary carriages, so 

 as to lessen the violence of the pressure on the collar, and to 

 utilize more fully the strength of the horse. 



CHAPTER III. 



TIIK nilTKUENT .M<MES OF PROGRESSION USED DY MAN. 



Description of the apparatus for the purpose of studying the various modes 

 of progression used l>y man Portable registering apparatus Experi- 

 mental apparatus for vertical reactions Walking Running Gallop 

 Leaping on two feet and hopping on one Notation of these various 

 methods Definition of a puce in any of these kinds of locomotion 

 Synthetic reproduction of the various modes of progression. 



TIIK principal modes of progression employed by animals, 

 are H-iilkiiKj, which we have already described at some length 

 as far as it relates to man, rwniiinj at different rates of speed, 

 t lie ijallop, and lett^iug on one or two feet. 



The act of walking varies at cording to the nature or the 

 slope of the ground; \ve shall have to treit of these dill'erei.t 



influences. 



in this new study it is no longer p ibbible to employ the 



