1882.] on Animals in Motion. 49 



the aid of electro-photographic exposures, are repeated by permission 

 of the President and Council from a paper read by the author before 

 the Royal Society, and are rendered more perfectly intelligible by the 

 reproductions of the actual motions projected on a screen through 

 the zoopraxiscope. 



The Walk, 



Selecting the horse for the purposes of illustration, we find that 

 during his slowest progressive movement — the walk — he has always 

 two, and, for a varying period, three feet on the ground at once. 

 With a fast walking horse the time of support upon three feet is 

 exceedingly brief ; while during a very slow walk all four feet are 

 occasionally on the ground at the same instant. 



The successive order of what may be termed foot fallings are 

 these. Commencing with the landing of the left hind foot, the next 

 to strike the ground will be the left fore foot, followed in order by 

 the right hind, and right fore foot. So far as the camera has revealed, 

 these successive foot fallings during the walk are invariable, and are 

 probably common to all quadrupeds. But the time during which 

 each foot, in its relation to the other feet, remains on the ground, 

 varies greatly with different species of animals, and even with the 

 same animal under different conditions. During an ordinary walk, 

 at the instant preceding the striking of the left hind foot, the body is 

 supported on the right laterals, and the left fore foot is in act of 

 passing to the front of the right fore foot. The two hind feet and 

 the right fore foot immediately divide the weight. The right hind 

 foot is now raised, and the left hind with its diagonal fore foot 

 sustains the body ; the left fore next touches the ground and for an 

 instant the animal is again on three feet ; the right fore foot is 

 immediately raised and again the support is derived from laterals — 

 the left instead of as before the right. One half of the stride is now 

 completed, and a similar series of alternations, substituting the right 

 feet for the left, completes the other half. These movements will 

 perhaps be more readily understood by a reference to the longitudinal 

 elevation, Fig. 7, No. 1, which illustrates some approximate relative 

 positions of the feet of a rapid walking horse, with a stride of 

 5 feet 9 inches. The positions of the feet indicated in this, and also in 

 the other strides illustrated in Fig. 7 are copied from photographs, 

 and from them we learn that during an ordinary walk the consecutive 

 supporting feet are : 



1. The left hind and left fore — laterals. 



2. Both hind, and left fore. 



3. Right hind and left fore — diagonals. 



4. Right hind and both fore. 



5. Right hind and right fore — laterals. 



6. Both hind, and right fore. 



7. Left hind and right fore — diarfonals. 



8. Left hind and both fore. 



Vol. X. (No. 75.) e 



