“Very little,” answered the Professor, “in fact, I can again best illustrate by suggesting a row-boat held steady by a boat-hook.”

“Just so,” answered Kearns slowly and with a thoughtful air; “I think I understand. And how long,” he continued, after a moment’s reflection, “would it take you to build a machine of this character?”

“Of what size?”

“Oh, the smallest size.”

“That would depend,” answered the Professor, “upon the facilities at my command. Given a shop fully and efficiently equipped, I could turn out my air-ship in a remarkably short time. Like most good things, it presents the merit of much simplicity after once the right principles have been discovered. You see——”

“What do you call a short time,” interrupted Kearns, “assuming you had the highest facilities?”

“Oh, I wouldn’t like to specify exactly——”

“Tell me,” broke in Kearns impetuously; “would it be a day—a month—a year?”

“Since you insist,” replied the Professor, “under pressure and assuming that I was furnished with the highest facilities, my invention is so well advanced and the practical details are so clearly outlined in my mind that I could produce an air-ship of the smaller type in from two to three weeks.”

Kearns sprang forward with a joyous exclamation.