But why do so many people dream that they are able to fly? Psychoanalysis answers diis question by stating that to fly or to be a bird in die dream is only a concealment of another wish, which one can recognize by more dian one linguistic or objective bridge. When die inquisitive child is told that a big bird like the stork brings the little children, when die ancients have formed the phallus winged, when the popular designation of the sexual activity of man is expressed in German by the word "to bird" (vogeJn), when the male member is directly called l'uccello (bird) by die Italians, all these facts are small fragments from a large collection which teaches us diat die wish to be able to fly signifies in die dream nothing more or less than die longing for the ability of sexual accomplishment. This is an early infantile wish. When die grown-up recalls his childhood it appears to him as a happy time in which one is happy for the moment and looks to die future widiout any wishes, it is for diis reason that he envies children. But if children themselves could inform us about it they would probably give different reports. It seems that childhood is not that blissful idyl into which we later distort it, diat on die contrary children are lashed through die years of childhood by the wish to become big, and to imitate the grown ups. This wish instigates all their playing. If in die course of their sexual investigation children feel that die grown up knows something wonderful in the mysterious and yet important realm diat they are prohibited from knowing or doing, they are seized with a violent wish to know it, and dream of it in the form of flying, or prepare this disguise of the wish for dieir later flying dreams. Thus aviation, which has attained its aim in our times, has also its infantile erotic roots.

By admitting diat he entertained a special personal relation to the problem of flying since his childhood, Leonardo bears out what we must assume from our investigation of children of our times, namely, diat his childhood investigation was directed to sexual matters. At least this one problem escaped the repression which later estranged him from sexuality. From childhood until die age of perfect intellectual maturity diis subject, slighdy varied, continued to hold his interest, and it is quite possible diat he was as little successful in his cherished art in die primary sexual sense as in his desires for mechanical matters, that both wishes were denied to him.

As a matter of fact the great Leonardo remained infantile in some ways throughout his whole life; it is said that all great men retain something of the infantile. As a grown up he still continued playing, which sometimes made him appear strange and incomprehensible to his contemporaries. He constructed the most artistic mechanical toys for court festivities and receptions, and we are dissatisfied thereby because we dislike to see the master waste his power on such petty stuff. He himself did not seem averse to giving his time to such things. Vasari reports that he did similar things even when not urged to it by request: "There (in Rome) he made a doughy mass out of wax, and when it softened he formed thereof very delicate animals filled with air; when he blew into them they flew in the air, and when the air was exhausted they fell to the ground. For a peculiar lizard caught by the wine-grower of Belvedere Leonardo made wings from skin pulled off from odier lizards, which he filled with mercury so that they moved and trembled when it walked; he then made for it eyes, a beard and horns, tamed it and put it in a little box and terrified all his friends with it.'"7 Such playing often served him as an expression of serious thoughts: "He had often cleaned the intestines of a sheep so well that one could hold them in the hollow of the hand; he brought them into a big room, and attached them to a blacksmith's bellows which he kept in an adjacent room, and then blew diem up until they filled up die whole room so diat everybody had to crowd into a corner. In diis manner he showed how they gradually became transparent and filled up with air, and as they were at first limited to very little space and gradually became more and more extended in the big room, he compared them to a genius.'"8 His fables and riddles evince die same playful pleasure in harmless concealment and artistic investment. The riddles were put into the form of prophecies, and almost all are rich in ideas, and devoid of wit to a remarkable degree.

The plays and jumps which Leonardo allowed his fantasy have in some cases quite misled his biographers who misunderstood diis part of his nature. In Leonardo's Milanese manuscripts one finds, for example, outlines of letters to the "Diodario of Sorio (Syria), viceroy of die holy Sultan of Babylon," in which Leonardo presents himself as an engineer sent to diese regions of die Orient in order to construct some works. In diese letters he defends himself against die reproach of laziness, he furnishes geographical descriptions of cities and mountains, and finally discusses a big elementary event which occurred while he was there.7'

In 1881, J.P. Richter8" had endeavored to prove from diese documents diat Leonardo made these traveler's observations when he really was in die service of die Sultan of Egypt, and that while in the Orient he embraced the Mohammedan religion. This sojourn in die Orient should have taken place in the time of 1483, that is, before he removed to die court of the Duke of Milan. However, it was not difficult for odier authors to recognize the illustrations of this supposed journey to die Orient as what diey really were, namely, fantastic productions of the youthful artist which he created for his own amusement, and in which he probably brought to expression his wishes to see the world and experience adventures.

A fantastic formation is probably also the 'Academia Vinciana, "die acceptance of which is due to the existence of five or six most clever and intricate emblems with the inscription of the Academy. Vasari mentions diese drawings but not the Academy.81 Miintz who placed such an ornament on the cover of his big work on Leonardo belongs to the few who believe in die reality of an "Academia Vinciana. "

It is probable that this impulse to play disappeared in Leonardo's marurer years, diat it became discharged in die investigating activity which signified die highest development of his personality. But die fact that it continued so long may teach us how slowly one tears oneself away from one's infantilism after having enjoyed in his childhood supreme erotic happiness which is later unattainable.