learned to preserve his equilibrium in ordinary walking he proceeds to complicate the problem by trying to walk on curbstones, in a rut, on a beam, on a balustrade or narrow wall. Unusual facility in these leads on to rope walking, and afterward turns out to be of great service to the mountain climber on narrow ridges and snow-covered ledges. A famous architect was so foolhardy as to walk round the narrow leads of the Königstuhl tower in Heidelberg, and it is recorded of the ancient Norse king Olav Tryggvason that he possessed the accomplishment, among others, of being able to run across the oars of a boat while the men were rowing. Another form of self-imposed difficulty and consequent conversion of locomotion into play is the attempt to step on all the cracks in the pavement or floor or on certain figures in a carpet. Something of this kind must have led to the game of Paradieshüpfen in Germany, hop-scotch in England, la Marelle in France, in which certain spaces are marked out in the sand or on a floor, on whose outlines the foot must not be set. Running games will form our next subject, and we find that the child’s earliest efforts for locomotion are as much like running as walking. His first steps alone are, it is true most hesitatingly made, but the nearer the goal, especially if it happens to be his mother kneeling with outstretched arms, the more rapid are his movements. Gradually the distinction between running and walking becomes more marked. For an example of genuine practice for a quick run Preyer’s observations may again be cited. He says that on the four hundred and fifty-ninth day the boy stopped short several times in his rapid course and stamped. In his seventy-seventh week this child ran nineteen times without stopping around a large table, calling out “mama,” and “bwa, bwa, bwa,”[178] the while. This simple running soon loses its charm, and is not much used later in play until it is transformed into a contest and acquires a new and higher meaning, of which we shall speak presently. Yet there are many running games whose attraction consists in the difficulties to be overcome, and very rapid running is a delight in itself, throwing us into a sort of transport and exciting in us “je ne sais quelle idée d’infini, de désir sans mesure, de vie surabondante et folle, je ne sais quel dedain de l’individualité quel besoin de se sentir aller sans se retenir, de se perdre dans le tout.”[179]