84 



ANIMAL LOCOMOTION. 



their movements are slowed, an arrangement which reduces 

 the degree of friction experienced by the several parts of the 

 limbs when they are, as it were, being drawn off the water 

 preparatory to a second extension. 



There are several grave objections to the ordinary or old 

 method of swimming just described. 1st, The body is laid 

 prone on the water, which exposes a large resisting surface 

 (fig. 4:1, A, B, C, p. 82). 2d, The arms and legs are spread 

 out on either side of the trunk, so that they are applied very 

 indirectly as propelling organs (fig. 41, 5, C). 3d, The most 

 effective part of the stroke of the arms and legs corresponds 

 to something like a quarter of an ellipse, the remaining three 

 quarters being dedicated to getting the arms and legs into 

 position. This arrangement wastes power and greatly in- 

 creases friction ; the attitudes assumed by the body at B and 

 C of fig. 41 being the worst possible for getting through the 

 water. 4th, The arms and legs are drawn towards the trunk 

 the one instant (fig. 41, A), and pushed away from it the next 

 (fig. 41, B). This gives rise to dead points, there being a 

 period when neither of the extremities are moving. The 

 body is consequently impelled by a series of jerks, the swim- 

 ming mass getting up and losing momentum between the 

 strokes. 



In order to remedy these defects, scientific swimmers have 

 of late years adopted quite another method. Instead of 

 working the arms and legs together, they move first the arm 

 and leg of one side of the body, and then the arm and leg of 

 the opposite side. This is known as the overhand movement, 

 and corresponds exactly with the natural walk of the giraffe, 

 the amble of the horse, and the swimming of the sea bear. 

 It is that adopted by the Indians. In this mode of swimming 

 the body is thrown more or less on its side at each stroke, 

 the body twisting and rolling in the direction of its length, 

 as shown at fig. 42, an arrangement calculated greatly to 

 reduce the amount of friction experienced in forward motion. 



The overhand movement enables the swimmer to throw 

 himself forward on the water, and to move his arms and legs 

 in a nearly vertical instead of a horizontal plane ; the ex- 

 tremities working, as it were, above and beneath the trunk, 



