90 



THE HORSE IN MOTION. 



Fig. 4. 



In No. 4 the upward impulse given by the fore leg may be supposed 

 to have reached its limit, the croup having passed above the gauge- 

 line marking the elevation, and the feet are all gathered under the 

 trunk more than a foot above the ground. There is now an oppor- 

 tunity for the animal to change their order; for, as has been stated, 

 he cannot change the order of his feet when one of them is on the 

 ground, and he is going at a rapid rate, without subjecting himself to 

 a fall. Although the distance passed over from the time the last foot 

 left the ground until the next one reaches it is only equal to the 

 interval of any of the feet, and the time that has elapsed while this 

 has been taking place does not exceed perhaps a fifth part of a 

 second, still it is sufficient to enable the animal to choose whether 

 he shall lead with one foot or the other in the next stride. But the 

 time, short as it is, is sufficient to cause a descent of four inches, and 

 the momentum acquired makes the contact with the earth a much 

 more serious matter than in any other portion of the stride. To make 

 it with either of the anterior extremities, or both, as is popularly be- 

 lieved to be the case, would seriously check the momentum, if it did 

 not result disastrously to the unlucky member. But this has been 

 shown over and over, by numerous observations at Palo Alto, never to 

 take place in running. The first check to the descent of the centre 



