_Mr Barlow._--Why, then, if the earth were to sink down from under our feet, lower and lower, what would happen? Would it have the same appearance? _Tommy._--No, sir; I think it must appear less and less, like the ship that is sailing away. _Mr Barlow._--Very right, indeed; but now attend to what I asked you just now. If a person could rise slowly into the air, and mount still higher and higher towards the sun, what would happen? _Tommy._--Why the same as if the earth were to sink from under us; it would appear less and less. _Mr Barlow._--Might not the earth then at least appear as small as the sun or moon does? _Tommy._--I can hardly conceive that, and yet I see it would appear less and less the farther we went. _Mr Barlow._--Do you remember what happened to you when you left the island of Jamaica? _Tommy._--Yes, I do. One of the blacks held me upon the deck, and then I looked towards the island, and I thought that it began to move away from the ship, though in reality it was the ship moving away from the land; and then, as the ship continued sailing along the water, the island appeared less and less. First, I lost sight of the trees and houses that stood on the shore; and then I could only see the highest mountains; and then I could scarcely see the mountains themselves; and at last the whole island appeared only like a dark mist above the water; and then the mist itself disappeared, and I could see nothing but a vast extent of water all round, and the sky above. _Mr Barlow._--And must not this be exactly the case if you could rise up into the air, higher and higher, and look down upon the earth? _Tommy._--Indeed it must. _Mr Barlow._--Now, then, you will be able to answer the question I asked you a little while ago: Could a person travel straight forward from the earth to the sun, how would they both appear to him as he went forward? _Tommy._--The earth would appear less and less as he went from it, and the sun bigger and bigger. _Mr Barlow._--Why, then, perhaps it would happen at last that the sun appeared bigger than the earth. _Tommy._--Indeed it might. _Mr Barlow._--Then you see that you must no longer talk of the earth's being large and the sun small, since that may only happen because you are nearer the one and at a great distance from the other; at least, you may now be convinced that both the sun and stars must be immensely bigger than you would at first sight guess them to be. As they were returning home they happened to pass through a small town on their way, and saw a crowd of people going into a house, which gave Mr Barlow the curiosity to inquire the reason. They were told that there was a wonderful person there who performed a variety of strange and diverting experiments. On Tommy's expressing a great desire to see these curious exhibitions, Mr Barlow took them both in, and they all seated themselves among the audience.