"The force of repulsion, which is little known, but just as powerful, is another that mankind may direct. Then there are the Polar electric forces, attracting objects toward the north or south poles. You have guessed something of this by the use of the compass, or electric needle. Opposed to these is centrifugal electric force, drawing objects from east to west, or in the opposite direction. This force is created by the whirl of the earth upon its axis, and is easily utilized, although your scientific men have as yet paid little attention to it.
"These forces, operating in all directions, absolute and immutable, are at the disposal of mankind. They will carry you through the atmosphere wherever and whenever you choose. That is, if you know how to control them. Now, here is a machine I have myself perfected."
The Demon drew from his pocket something that resembled an open-faced watch, having a narrow, flexible band attached to it.
"When you wish to travel," said he, "attach this little machine to your left wrist by means of the band. It is very light and will not be in your way. On this dial are points marked 'up' and 'down' as well as a perfect compass. When you desire to rise into the air set the indicator to the word 'up,' using a finger of your right hand to turn it. When you have risen as high as you wish, set the indicator to the point of the compass you want to follow and you will be carried by the proper electric force in that direction. To descend, set the indicator to the word 'down.' Do you understand?"
"Perfectly!" cried Rob, taking the machine from the Demon with unfeigned delight. "This is really wonderful, and I'm awfully obliged to you!"
"Don't mention it," returned the Demon, dryly. "These three gifts you may amuse yourself with for the next week. It seems hard to entrust such great scientific discoveries to the discretion of a mere boy; but they are quite harmless, so if you exercise proper care you can not get into trouble through their possession. And who knows what benefits to humanity may result? One week from to-day, at this hour, I will again appear to you, at which time you shall receive the second series of electrical gifts."
"I'm not sure," said Rob, "that I shall be able again to make the connections that will strike the Master Key."
"Probably not," answered the Demon. "Could you accomplish that, you might command my services forever. But, having once succeeded, you are entitled to the nine gifts--three each week for three weeks--so you have no need to call me to do my duty. I shall appear of my own accord."
"Thank you," murmured the boy.
The Demon bowed and spread his hands in the form of a semi-circle. An instant later there was a blinding flash, and when Rob recovered from it and opened his eyes the Demon of Electricity had disappeared.
4. Testing the Instruments
There is little doubt that this strange experience befallen a grown man he would have been stricken with a fit of trembling or a sense of apprehension, or even fear, at the thought of having faced the terrible Demon of Electricity, of having struck the Master Key of the world's greatest natural forces, and finding himself possessed of three such wonderful and useful gifts. But a boy takes everything as a matter of course. As the tree of knowledge sprouts and expands within him, shooting out leaf after leaf of practical experience, the succession of surprises dulls his faculty of wonderment. It takes a great deal to startle a boy.
Rob was full of delight at his unexpected good fortune; but he did not stop to consider that there was anything remarkably queer or uncanny in the manner in which it had come to him. His chief sensation was one of pride. He would now be able to surprise those who had made fun of his electrical craze and force them to respect his marvelous powers. He decided to say nothing about the Demon or the accidental striking of the Master Key. In exhibiting to his friends the electrical devices he had acquired it would be "no end of fun" to mark their amazement and leave them to guess how he performed his feats.