Most valuable art for a pitcher is the change of pace, in which the moundsman. varies the speed of his throws while seeming to maintain the same full sweep of his arm. Batters judge their step to meet the pitch, with the arm motion of the pitcher, so that a good change of pace often catches them between strides and throws them off balance. Stainback of the Cubs, however, has mastered the art of closely studying the various pitching speeds, such as a fast ball, then a slow one, and setting himself firmly for the swing.