3. Try the following experiment and relate the results to the matter of automatic control brought about by habit: Draw a star on a sheet of cardboard. Place this on a table before you, with a hand-mirror so arranged that you can see the star in the mirror. Now trace the outline of the star with a pencil, looking steadily in the mirror to guide your hand. Do not lift the pencil from the paper from the time you start until you finish. Have others try this experiment. 4. Study some group of pupils for their habits (1) of attention, (2) of speech, (3) of standing, sitting, and walking, (4) of study. Report on your observations and suggest methods of curing bad habits observed. 5. Make a list of "mannerisms" you have observed, and suggest how they may be cured. 6. Make a list of from ten to twenty habits which you think the school and its work should especially cultivate. What ones of these are the schools you know least successful in cultivating? Where does the trouble lie? CHAPTER VI SENSATION We can best understand the problems of sensation and perception if we first think of the existence of two great worlds--the world of physical nature without and the world of mind within. On the one hand is our material environment, the things we see and hear and touch and taste and handle; and on the other hand our consciousness, the means by which we come to know this outer world and adjust ourselves to it. These two worlds seem in a sense to belong to and require each other. For what would be the meaning or use of the physical world with no mind to know or use it; and what would be the use of a mind with nothing to be known or thought about? 1. HOW WE COME TO KNOW THE EXTERNAL WORLD There is a marvel about our coming to know the external world which we shall never be able fully to understand. We have come by this knowledge so gradually and unconsciously that it now appears to us as commonplace, and we take for granted many things that it would puzzle us to explain. KNOWLEDGE THROUGH THE SENSES.--For example, we say, "Of course I see yonder green tree: it is about ten rods distant." But why "of course"? Why should objects at a distance from us and with no evident connection between us and them be known to us at all merely by turning our eyes in their direction when there is light? Why not rather say with the blind son of Professor Puiseaux of Paris, who, when asked if he would like to be restored to sight, answered: "If it were not for curiosity I would rather have long arms. It seems to me that my hands would teach me better what is passing in the moon than your eyes or telescopes."