As Frank finished, a voice in the back of the hall cried:
Merry looked in the direction from whence the sound seemed to come.
"I have no educated rats," he said, quietly; "but if the person who called for them will come forward, I will show the audience an educated monkey."
This caused a laugh, and several persons in the rear of the theater turned to look toward the one who had uttered the cry, a flashily-dressed youth who had entered a few minutes before.
This person grinned a bit, but did not accept Frank's invitation to come forward.
Merry retired, and the curtain was dropped for a few moments.
When the professor finished playing on the piano, the curtain rose swiftly, showing on the stage an easel, against which rested a large mirror in a gilt frame. This mirror was about four and a half feet wide, and three feet high.
"You will see, ladies and gentlemen," he said, "that I have had this mirror placed in a position where the light falls strongly upon it, and I think you will be able to follow the movements of the fly from any part of the house. First, I wish to show you the mirror."
He then took the mirror down from the easel, and, having shown both sides to the audience, rested it on the floor, leaning it against the easel.
Next he took the glass from the frame and showed that to the audience.
"It is just an ordinary mirror, as you can all see," he said.
Having shown the glass, he rested that against the easel, and took up the frame, which had a wooden back, and showed that to the audience. Then the frame was placed on the easel in its proper position, while the glass still leaned against the bottom part, which it covered up as far as the lower edge of the frame.
As it stood thus, Frank talked glibly a few moments, then he picked up the glass and returned it carefully to the frame.
"Now," he said, taking a piece of soap, "I am going to divide this mirror into twenty-eight even squares."
"Next," explained Merry, "I will number twenty-six of those squares in order as they come, like this."
"The next square I will mark zero--thus. The last one I will leave blank. That shall be a starting point. Now we will letter those squares in the same manner from 'a' to 'z.'"
"At last," he smiled, "we are ready for the wonderful fly."