Rob was a courageous boy, but a thrill of fear passed over him in spite of his bravest endeavor as he gazed upon the wondrous apparition that confronted him. For several moments he sat as if turned to stone, so motionless was he; but his eyes were nevertheless fastened upon the Being and devouring every detail of his appearance.  
And how strange an appearance he presented!
 
His jacket was a wavering mass of white light, edged with braid of red flames that shot little tongues in all directions. The buttons blazed in golden fire. His trousers had a bluish, incandescent color, with glowing stripes of crimson braid. His vest was gorgeous with all the colors of the rainbow blended into a flashing, resplendent mass. In feature he was most majestic, and his eyes held the soft but penetrating brilliance of electric lights.
 
It was hard to meet the gaze of those searching eyes, but Rob did it, and at once the splendid apparition bowed and said in a low, clear voice:
 
"I am here."
 
"I know that," answered the boy, trembling, "but WHY are you here?"
 
"Because you have touched the Master Key of Electricity, and I must obey the laws of nature that compel me to respond to your summons."
 
"I—I didn't know I touched the Master Key," faltered the boy.
 
"I understand that. You did it unconsciously. No one in the world has ever done it before, for Nature has hitherto kept the secret safe locked within her bosom."
 
Rob took time to wonder at this statement.
 
"Then who are you?" he inquired, at length.
 
"The Demon of Electricity," was the solemn answer.
 
"Good gracious!" exclaimed Rob, "a demon!"
 
"Certainly. I am, in truth, the Slave of the Master Key, and am forced to obey the commands of any one who is wise and brave enough—or, as in your own case, fortunate and fool-hardy enough—to touch it."
 
"I—I've never guessed there was such a thing as a Master Key, or—or a Demon of Electricity, and—and I'm awfully sorry I—I called you up!" stammered the boy, abashed by the imposing appearance of his companion.
 
The Demon actually smiled at this speech,—a smile that was almost reassuring.
 
"I am not sorry," he said, in kindlier tone, "for it is not much pleasure waiting century after century for some one to command my services. I have often thought my existence uncalled for, since you Earth people are so stupid and ignorant that you seem unlikely ever to master the secret of electrical power."
 
"Oh, we have some great masters among us!" cried Rob, rather nettled at this statement. "Now, there's Edison—"
 
"Edison!" exclaimed the Demon, with a faint sneer; "what does he know?"
 
"Lots of things," declared the boy. "He's invented no end of wonderful electrical things."
 
"You are wrong to call them wonderful," replied the Demon, lightly. "He really knows little more than yourself about the laws that control electricity. His inventions are trifling things in comparison with the really wonderful results to be obtained by one who would actually know how to direct the electric powers instead of groping blindly after insignificant effects. Why, I've stood for months by Edison's elbow, hoping and longing for him to touch the Master Key; but I can see plainly he will never accomplish it."
 
"Then there's Tesla," said the boy.
 
The Demon laughed.
 
"There is Tesla, to be sure," he said. "But what of him?"
 
"Why, he's discovered a powerful light," the Demon gave an amused chuckle, "and he's in communication with the people in Mars."
 
"What people?"
 
"Why, the people who live there."
 
"There are none."
 
This great statement almost took Rob's breath away, and caused him to stare hard at his visitor.
 
"It's generally thought," he resumed, in an annoyed tone, "that Mars has inhabitants who are far in advance of ourselves in civilization. Many scientific men think the people of Mars have been trying to signal us for years, only we don't understand their signals. And great novelists have written about the Martians and their wonderful civilization, and—"
 
"And they all know as much about that little planet as you do yourself," interrupted the Demon, impatiently. "The trouble with you Earth people is that you delight in guessing about what you can not know. Now I happen to know all about Mars, because I can traverse all space and have had ample leisure to investigate the different planets. Mars is not peopled at all, nor is any other of the planets you recognize in the heavens. Some contain low orders of beasts, to be sure, but Earth alone has an intelligent, thinking, reasoning population, and your scientists and novelists would do better trying to comprehend their own planet than in groping through space to unravel the mysteries of barren and unimportant worlds."
 
Rob listened to this with surprise and disappointment; but he reflected that the Demon ought to know what he was talking about, so he did not venture to contradict him.
 
"It is really astonishing," continued the Apparition, "how little you people have learned about electricity. It is an Earth element that has existed since the Earth itself was formed, and if you but understood its proper use humanity would be marvelously benefited in many ways."
 
"We are, already," protested Rob; "our discoveries in electricity have enabled us to live much more conveniently."
 
"Then imagine your condition were you able fully to control this great element," replied the other, gravely. "The weaknesses and privations of mankind would be converted into power and luxury."
 
"That's true, Mr.—Mr.—Demon," said the boy. "Excuse me if I don't get your name right, but I understood you to say you are a demon."
 
"Certainly. The Demon of Electricity."
 
"But electricity is a good thing, you know, and—and—"
 
"Well?"
 
"I've always understood that demons were bad things," added Rob, boldly.
 
"Not necessarily," returned his visitor. "If you will take the trouble to consult your dictionary, you will find that demons may be either good or bad, like any other class of beings. Originally all demons were good, yet of late years people have come to consider all demons evil. I do not know why. Should you read Hesiod you will find he says:
 
'Soon was a world of holy demons made,
Aerial spirits, by great Jove designed
To be on earth the guardians of mankind.'"
 
"But Jove was himself a myth," objected Rob, who had been studying mythology.
 
The Demon shrugged his shoulders.
 
"Then take the words of Mr. Shakespeare, to whom you all defer," he replied. "Do you not remember that he says:
 
'Thy demon (that's thy spirit which keeps thee) is
Noble, courageous, high, unmatchable.'"
 
"Oh, if Shakespeare says it, that's all right," answered the boy. "But it seems you're more like a genius, for you answer the summons of the Master Key of Electricity in the same way Aladdin's genius answered the rubbing of the lamp."
 
"To be sure. A demon is also a genius; and a genius is a demon," said the Being. "What matters a name? I am here to do your bidding."