170 



ANIMAL MECHANISM. 



The figure which represents it is rather strange ; the eye is 

 but little accustomed to see this time of the gallop, which is 

 doubtless very rare. When considering this ungraceful figure, 

 we are tempted to say with De Curnieu, *^the province of 

 painting is what one sees, and not what really exists." 



The gallop in four- time differs from that which has just 

 been described only in this point, that the impacts of the 

 diagonal biped, which constitute the second time, are disunited 

 and give distinct sounds ; we see an example of this in fig. 62. 



^TEMPS. A 



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^ ■ ■ /I 



1 



2| 



1.3^1 3 l2l 



1 





Fig. 62.— Notation of the gallop in four- time. (A) determination of eacii 

 of the successive times. (B) determination of the number of feet which 

 support the body at each instant. 



According to this notation, the body, at lirst suspended, is 

 borne successively on one foot, on three, on two, on three, and 

 on one, after which a new suspension recommences. 



Of the full gallop. — This very rapid pace could not be 

 studied by means of the apparatus which we have employed 

 hitherto. It was necessary to construct a special registering 

 instrument, and new experimental apparatus. 



To leave the two hands of the rider free, the registering 

 instrument was enclosed in a flat box, attached to the back of 

 the horseman by straps like the knapsack of the soldier. We 

 shall not attempt the detailed description of this instrument, 

 which carried five levers, tracing on smoked glass the curves 

 of the action of the four legs, and the reaction of the withers. 

 The violence of the impacts on the ground is such that they 

 would instantly have broken the apparatus before employed. 

 We have substituted for this a copper tube, in which moves a 

 leaden piston, suspended between two spiral springs. The 

 shocks given to this piston at each footfall, produce an effect 

 like that of an air-pump acting on the registers. A ball of 

 india-rubber, which can be pressed between the teeth, sets the 



