shadow. If now I raise the smaller ball a little, you observe a portion of the light from the candle falls upon its upper part, while the lower part is still in the shadow, thus representing a partial eclipse.

From this, it will be plain to you, that by changing the situation of the smaller ball, and bringing it between the larger one and the candle, in a direct line, a total eclipse of the sun would be represented; but as the moon is so much smaller than the sun, we always observe in this case a ring of light surrounding the darkened part; on which account such an eclipse of the sun is termed an annular eclipse. An eclipse of the sun can only happen at the time of a new moon; and an eclipse of the moon can never take place but at the time of the full.

But here is a further figure, representing the doctrine of the eclipses, which you will readily comprehend, if have attended to my remarks; and this figure shows also, at one

you

view, the manner of the eclipses, both of sun and moon. Let S represent the sun, E the

earth, and M M the moon, it is obvious, that when the moon is in a line between the earth and the sun, she will conceal part of that luminary from the view of the spectators on the earth's surface; and, on the contrary, when the earth is in a line between the sun and the moon, the moon will be immersed in the dark shadow of the earth.

K

CHAP. XXIII.

SOMETHING MORE ABOUT ECLIPSES.

THE eclipse of which I have now told you was an eclipse of the sun; that is, the moon came between the earth and sun, and prevented the sun from shining on the earth. A total eclipse of the sun does not frequently happen. Sometimes, too, an eclipse takes place in one country and not in another.

For instance, suppose an eclipse of the sun to take place in China about noon. Now you remember that when it is noon in China, it is nearer night with us. Of course, the eclipse of the sun in China might not be visible here, for at the time of the eclipse, it might be nearer night here.

But sometimes the earth gets exactly between

Can an eclipse of the sun here, be seen in China? Why not?

the sun and moon. The consequence of this is, that the moon is eclipsed. The earth being between the sun and moon, prevents the sun from shining on the moon, or deprives the moon of its light.

I

The moon being deprived of its light, cannot shine upon the earth. Eclipses of the moon are much more frequent than eclipses of the sun. have seen many eclipses of the moon. It is interesting to witness them; but they are not so striking as eclipses of the sun.

Some of the other planets are subject to eclipses. In the various movements of these heavenly bodies round the sun, one planet occasionally passes between the sun and another planet, and thus transiently deprives it of the light for which it is dependent upon that great luminary.

What causes an eclipse of the moon?

Do eclipses ever happen to the other planets? How?

CHAP. XXIV.

A WORD OR TWO MORE ABOUT THE ECLIPSES OF THE SUN. CENTRAL ECLIPSES. TOTAL ECLIPSES. ANNULAR ECLIPSES.

Now that we are again talking of the sun, I will add a little to what I have already said concerning its eclipses.

You understand that an eclipse of the sun, or the hiding of a greater or less proportion of the whole face of the sun, from that part of the earth upon which the eclipse is seen, has its cause in the passing, either of the whole of the moon, or of a part of the moon, between the earth and the sun. You understand that all the three great bodies (the earth, the moon, and the sun) are at immense distances from each other, and the moon between the other two; so, that the moon, when, in whole or in between the earth and the sun, will hide the sun

part, it passes