464 



NATURE 



[March 20, 1879 



which probably remain submerged for ever ; I have not 

 yet ascertained whether these submerged flowers are 

 fertile ; if they are so, they can hardly fail to be cleisto- 

 gamic. Fritz Muller 



A STUDY IN LOCOMOTION'^ 

 II. 

 III. The Paces of the Horse. — Every one can recognise 

 whether a horse is walking, trotting, or galloping, and 

 yet few would be able to point out the rhythm and order 

 of succession of the movements of the limbs in different 

 paces. These movements, in fact, succeed each other 



Fig. 8. — Registering apparatus for horse's pace?. 



too rapidly for the eye to follow them, and their rhythmic 

 succession is more readily perceived by the ear than by 

 the eye. It is indeed ordinarily by the ear that we 

 become aware of a horse's pace. When at each return 

 of the step {revolution dii pas) we hear two distinct 

 strokes of the hoofs, we call it an amble, or a trot ; three 



8 



1 





Fig. 9. — Synoptic table of the different paces cf the hor.-e, after the classic 

 authors: i, amble; 5, foot-pace; 8, trot, &c. 



Strokes unequally separated denote a gallop ; lastly, four 

 strokes indicate a foot pace. But these paces may be 



"Moteurs animus; Experiences de Physiolcgle graphique." Lecture 

 by Prof. Marey at the Paris meeting of the French Association, August 20, 

 1878. 



more or less irregular, variable, or crippled ; besides that, 

 when an animal passes in a very short space of time from 

 one pace to another, how shall we decide upon the 

 manner in which the transition is effected ? To ctear up 

 these points great efforts have been made by horsc- 



FiG. 10. — Notations of two airs, a and b, executed upon the keyboard of a 

 harmonium. 



trainers and veterinary surgeons, to whom the questions 

 involved are of considerable importance. 



Now, as I have just said, the ear judges better than the 

 eye as to the rhythm of successive movements, but in 

 order to demonstrate the production of these rhythmic 

 strokes in twos, and threes, and fours, it is essential to 

 know to which foot each separate sound is to be attri- 

 buted. Ingenious experimenters have attached to the 

 four feet of the horse bells of different tones, but in 

 perfect harmony with each other. Varied melodies or 

 harmonies are thus produced, according to the succession 

 or synchronism of the strokes. But such an arrangement 

 would certainly not give the length of time each foot 

 remained upon the ground, therefore the question of the 

 paces of the horse has not been entirely resolved even by 

 this method. Turn to any special treatises on the subject, 

 and you will see that beyond the amble, the downright 



Gallop of 3 stefs. a, ind.cations of the three s eps ; h, indxatlons of the 

 number of feet which form the supp'.rt of the body at each instant of 

 the gaU p of 3 steps. 



Fig. 



Gall p or 4 src; s. 

 -Xctations of the gallop of 3 and 4 steps. 



trot, and the three-step gallop, there is, perhaps, not a 

 single pace respecting which contradictory theories are 

 not held. In face of the difficulties of this problern, you 

 will doubtless foresee what will be my conclusion ; it will 

 be necessary to have recourse to the graphic method 

 which will solve the question in the simplest manner 

 possible. 



