ABSTRACT
In the last chapter, we considered the transmission of a motion, but one initiated by the child himself and one in which the moving bodies were contiguous. The situation we shall now consider involves the motion of three balls. The first of these A (a red ball) is released by a mechanical device from the top of a slope. It then hits the wooden plug P 1, whch is fixed to the slope (a fact to which the child's attention is drawn) and transmits the motion to a second (green) ball B, which, in turn, hits the stopper Pa made of Plasticine. The Plasticine is removed, whereupon the ball B hits the second (fixed) plug P2
behind which lies a third ball C, but at some distance from the plug. The ball C therefore remains immobile.
