To give the child the habit of attention and to impress him deeply with any truth affecting the senses, let him pass several restless days before he discovers that truth. If the one in question does not thus impress him, you may make him see it more clearly by reversing the problem. If he does not know how the sun passes from its setting to its rising, he at least does know how it travels from its rising to its setting; his eyes alone teach him this. Explain your first question by the second. If your pupil be not absolutely stupid, the analogy is so plain that he cannot escape it. This is his first lesson in cosmography. As we pass slowly from one sensible idea to another, familiarize ourselves for a long time with each before considering the next, and do not force our pupil's attention; it will be a long way from this point to a knowledge of the sun's course and of the shape of the earth. But as all the apparent motions of the heavenly bodies are upon the same principle, and the first observation prepares the way for all the rest, less effort, if more time, is required to pass from the daily rotation of the earth to the calculation of eclipses than to understand clearly the phenomena of day and night. Since the sun (apparently) revolves about the earth, it describes a circle, and we already know that every circle must have a centre. This centre, being in the heart of the earth, cannot be seen; but we may mark upon the surface two opposite points that correspond to it. A rod passing through these three points, and extending from one side of the heavens to the other, shall be the axis of the earth, and of the sun's apparent daily motion. A spherical top, turning on its point, shall represent the heavens revolving on their axis; the two extremities of the top are the two poles. The child will be interested in knowing one of them, which I will show him near the tail of Ursa Minor. This will serve to amuse us for one night. By degrees we shall grow familiar with the stars, and this will awaken a desire to know the planets and to watch the constellations. We have seen the sun rise at midsummer; we will also watch its rising at Christmas or some other fine day in winter. For be it known that we are not at all idle, and that we make a joke of braving the cold. I take care to make this second observation in the same place as the first; and after some conversation to pave the way for it. One or the other of us will be sure to exclaim, "How queer that is! the sun does not rise where it used to rise! Here are our old landmarks, and now it is rising over yonder. Then there must be one east for summer, and another for winter." Now, young teacher, your way is plain. These examples ought to suffice you for teaching the sphere very understandingly, by taking the world for your globe, and the real sun instead of your artificial sun. Things Rather than their Signs.