"Oh, Robert!" cried his mother, with tears in her loving eyes, "you don't know how we've all worried about you for the past week!"
"A week?" asked Rob, with surprise.
"Yes; it's a week to-morrow morning since you flew into the air and disappeared."
"Then," said the boy, thoughtfully, "I've reached home just in time."
"In time for what?" she asked.
But he did not answer that question. He was thinking of the Demon, and that on the afternoon of this very day he might expect the wise and splendid genius to visit him a second time.
At luncheon, although he did not feel hungry, he joined the family at table and pleased his mother by eating as heartily as of old. He was surprised to find how good the food tasted, and to realize what a pleasure it is to gratify one's sense of taste. The tablets were all right for a journey, he thought, but if he always ate them he would be sure to miss a great deal of enjoyment, since there was no taste to them at all.
At four o'clock he went to his workshop and unlocked the door. Everything was exactly as he had left it, and he looked at his simple electrical devices with some amusement. They seemed tame beside the wonders now in his possession; yet he recollected that his numerous wires had enabled him to strike the Master Key, and therefore should not be despised.
Before long he noticed a quickening in the air, as if it were suddenly surcharged with electric fluid, and the next instant, in a dazzling flash of light, appeared the Demon.