86 



ANIMAL LOCOMOTION. 



is the most expeditious yet discovered, but it is fatiguing, and 

 can only be indulged in for short distances. 



An improvement on the foregoing for long distances is 

 that known as the side stroke. In this method, as the term 

 indicates, the body is thrown more decidedly upon the side. 

 Either side may be employed, some preferring to swim on the 

 right side, and some on the left ; others swimming alternately 

 on the right and left sides. In swimming by the side stroke 

 (say on the left side), the left arm is advanced in a curve, 

 and made to describe the upper side of an ellipse, as repre- 

 sented at (X & of fig. 43. This done, the right arm and legs are 

 employed as propellers, the right arm and legs making a 

 powerful backward stroke, in which the concavity of the hand 



Fia. 43. — Gide-stroke Swimming. — Original, 



is directed backwards and outwards, as shown at c d of the 

 same figure.-^ The right arm in this movement describes 

 the under side of an ellipse, and acts in a nearly vertical 

 plane. When the right arm and legs are advanced, some 

 swimmers lift the right arm out of the water, in order to 

 diminish friction — the air being more easily penetrated 

 than the water. The lifting of the arm out of the water 

 increases the speed, but the movement is neither graceful 

 nor comfortable, as it immerses the head of the swimmer 

 at each stroke. Others keep the right arm in the water 

 and extend the arm and hand in such a manner as to 

 cause it to cut straight forward. In the side stroke the left 

 arm (if the operator swims on the left side) acts as a cutwater 

 (fig. 43, h). It is made to advance when the right arm 



^ The outward direction given to the arm and hand enables them to force 

 away the back water from the body and limbs, and so reduce the friction to 

 forward motion. ' 



