“I am satisfied,” said Miss Villers, “and I thank you, and Sir David Brewster, for the lecture; and now,” continued the lady, “how will you explain the circumstance of my name having been so audibly pronounced, and from a spot which made it impossible that it should have come from any human being?” “It was the solitary spirit of the dell,” said Mr. Seymour, with a smile; “a rural spirit who is disposed to become very loquacious whenever the repose of her habitation is disturbed. I can assure you,” added he, “that you are not the first person whom her gambols have surprised and terrified in the shades of evening. I presume you have discovered that I allude to that unseen musician of the air--ECHO.” “Indeed, Mr. Seymour, the sound could not have been the effect of an echo, for I never spoke,” replied Miss Villers. “Very likely, but I happen to know that Mrs. Seymour called you by name at the orchard gate.” “Nor will that explain it,” observed Miss Villers, “for in that case I must certainly have heard her, whereas the sound came in a very different direction, from the inaccessible rocks of sandstone.” “Young lady,” said Mr. Seymour, “you must forgive me for telling you that your philosophy is at fault. It is as possible to hear an echo, without recognising the direct sound which produced it, as it is for two persons to be so placed as to see each other in a looking-glass, although objects might obstruct the direct view of themselves. Did you never walk between an irregular wall and a row of houses, or along a valley intercepted by houses during the ringing of a peal of bells? Nothing is more common under such circumstances, for the sound instead of arriving at the ear, in its true direction, to be reflected in one that is opposite to it;--now before we quit the subject of optical illusion, let me relate an incident which occurred to myself. I presume you are all acquainted with the appearance in the grass, called a _Fairy-ring_?” “To be sure,” said Tom, “a very dark circle of grass, around which there is generally a ring that looks as if the ground had been burnt.”