Again the atmosphere quickened and pulsed with accumulating vibrations. Again the boy found himself aroused to eager expectancy. There was a whirl in the air; a crackling like distant musketry; a flash of dazzling light--and the Demon stood before him for the third time.
"I give you greetings!" said he, in a voice not unkindly.
"Good afternoon, Mr. Demon," answered the boy, bowing gravely.
"I see you have returned safely from your trip," continued the Apparition, cheerfully, "although at one time I thought you would be unable to escape. Indeed, unless I had knocked that tube from the rascally Turk's hand as he clambered to the top of the wall, I believe you would have been at the Yarkand oasis yet--either dead or alive, as chance might determine."
"Were you there?" asked Rob.
"To be sure. And I recovered the tube for you, without which you would have been helpless. But that is the only time I saw fit to interfere in any way."
"I'm afraid I did not get a chance to give many hints to inventors or scientists," said Rob.
"True, and I have deeply regretted it," replied the Demon. "But your unusual powers caused more astonishment and consternation than you, perhaps, imagined; for many saw you whom you were too busy to notice. As a result several able electricians are now thinking new thoughts along new lines, and some of them may soon give these or similar inventions to the world."
