You have often told me, Sir, that the sun did not move, but the earth on which we live goes round the sun. If so, why do you say, the sun sets? DR. BARTLETT. That is a manner of speaking which has been taken from the earliest times, and the term is generally used, though the same sense is not annexed to it. They thought formerly that the sun moved round the earth, which it seems to do; but we now know better, after further enquiries, and various observations. CHARLES. Should we then say that the sun moves? DR. BARTLETT. If you were in a boat, you would say with as much propriety, that the land and the trees moved, by which you failed; and yet they do not move. CHARLES. That is true, I have often observed it; but how comes it, that we do not feel the motion of the earth? DR. BARTLETT. Because you are accustomed to it from your birth, and the motion of so vast a body cannot be felt by so small a creature as man is, in proportion. The sun is much larger than the earth; thus it is most reasonable to conceive, arguing from what we know of the wisdom of the great Mover, that the earth goes round the sun, than that the sun moves round the earth. WILLIAM. And is the sun, Sir, so very large? DR. BARTLETT. It is well known to astronomers, that the sun is above a million of times bigger than the earth: judge then how large it must be. WILLIAM. But how do you know all this? DR. BARTLETT. By careful investigation; and as you are fond of reading, you may yourself be convinced of it; Charles will lend you the Spectacle de la Nature[1]. In that excellent book you will find instruction delivered in an easy manner. Footnote 1: On this subject a more useful book has been lately published, entitled, An Introduction to Astronomy. CHARLES. But I must yet ask you, Sir, how can the sun, which you say is about ninety-five millions of miles from us, give us so much warmth and light? DR. BARTLETT. That is truly a great miracle of almighty Power. WILLIAM. I am glad I know that the sun is so large. Many think it is not larger than it appears to us. DR. BARTLETT. The further any thing is from us, the smaller it appears; as that kite for instance, it will appear much less in the air, than it does on the ground. CHARLES. Certainly; and this is also a proof, that the sun must be amazingly great, because that it is at such an immense distance from us. The moon, by the same rule, must be very large. DR. BARTLETT.