Mr Barlow.—What, then, does the same thing sometimes appear small and sometimes great?
Tommy.—Yes, sir; it seems small when it is at a great distance; for I have observed even houses and churches when you are at some miles' distance,
seem to the eye very small indeed; and now I observe that the vessel is sailing towards us, and it is not, as I imagined, a little fishing-boat, but a ship with a mast, for I begin to distinguish the sails.
Mr Barlow walked on a little while by the side of the sea, and presently Tommy called out again: "I protest I was mistaken again; for it is not a vessel with one mast, as I thought a little while ago, but a fine large ship with three great masts, and all her sails before the wind. I believe she must either be a large merchantman or else a frigate."
Mr Barlow.—Will you then take notice of what you have now been saying? What was first only a little dusky speck became a vessel with one mast, and now this vessel with one mast plainly appears a ship of a very large size, with all her masts and sails, and rigging complete. Yet all these three appearances are only the same object at different distances from your eye.
Tommy.—Yes, sir; that is all very true indeed.
Mr Barlow.—Why, then, if the ship, which is now, full in sight, were to tack about again, and sail away from us as fast as she approached just now what do you think would happen?
Tommy.—It would grow less and less every minute, till it appeared a speck again.
Mr Barlow.—You said, I think, that the sun was a very small body, not bigger than a round table?
Tommy.—Yes, sir.