"We will soon go much faster," announced Professor Roumann. "I have not yet had a chance to test my Cardite motor to its fullest speed, and I think I will do so. I wish to see if it will equal my Etherium machine. I'll turn on the power gradually now, and we'll see what happens."
"How fast do you think it ought to send us along?" asked Jack.
"Oh, perhaps one hundred and twenty-five miles a second. You know we went a hundred miles a second when we headed for Mars. I would not be surprised if we made even one hundred and thirty miles a second with the Cardite."
"Whew! If we ever hit anything going like that!" exclaimed old Andy
Sudds.
"We'd go right through it," finished Jack fervently. The professor was soon ready for the test. Slowly he shoved over the controlling lever. The Cardite motor hummed more loudly, like some great cat purring. Louder snapped the electrical waves. The air vibrated with the enormous speed of the valve wheels, and there was a prickling sensation as the power flowed into the positive and negative plates, by which the projectile was moved through space.
"Watch the hand of the speed indicator, boys," directed Professor Roumann, "while Professor Henderson and I manipulate the motor. Call out the figures to us, for we must keep our eyes on the valves." Slowly the speed indicator hand, which was like that of an automobile speedometer, swept over the dial.
"Fifty miles a second," read off Mark. The two professors shoved the levers over still more.
"Seventy-five," called Jack.
"Give it a little more of the positive current," directed Mr. Roumann.
"Ninety miles a second," read Mark a few moments later.