urse to others only when he
finds himself really helpless, he will examine every new object for a
long time without saying a word. He is thoughtful, and not disposed to
ask questions. Be satisfied, therefore, with presenting objects at
appropriate times and in appropriate ways. When you see his curiosity
fairly at work, ask him some laconic question which will suggest its
own answer.

On this occasion, having watched the sunrise from beginning to end with
him, having made him notice the mountains and other neighboring objects
on the same side, and allowed him to talk about them just as he
pleases, be silent for a few minutes, as if in deep thought, and then
say to him, "I think the sun set over there, and now it has risen over
here. How can that be so?" Say no more; if he asks questions, do not
answer them: speak of something else. Leave him to himself, and he
will be certain to think the matter over.

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 thre