The professor smiled, thinking how keen this young man always proved himself to be.
"You've guessed it," he replied. "And I'm sorry I can't explain more to you."
"We understand," said Jack. "And no doubt this machine is a super-catapult."
"True," was the answer. "Of untold use to the scientific world. For the present I shall confine testing its efficiency right in this place. Now is my chance."
"But of what advantage will it be to our flying machine to start it in this way?" "Stop and think, my boy," said the professor. "Just as an aeroplane can literally be shot into the air within a very short space, so can your airship. Of course, this is not necessary, but we will be able to start the ship much faster that way than we could withjust the motors."
"You'll make history, Professor," added Jack. "Exciting headlines for the papers."
"Sure enough," said Mark enthusiastically.
"The publicity doesn't interest me," replied the scientist. "Moreover, my super-catapult must remain a secret, as I told you a while ago."
"So you really propose to launch the Snowbird in this way?" asked
Jack.
"We will be shot into the air. If you are sure of your machine, I am sure of my catapult, and we will try the two contrivances together."