At this the giant grinned at his rival.
"At the same time," went on Tom, winking an eye at Mr. Damon, "Eradicate knows a little more about garden work, on account of having done it so many years."
"Ha! Whut I tell yo', Giant!" boasted the colored man. It was his turn to smile.
"And so," went on Tom, judicially, "I guess I'll let Rad finish spading the garden, and you, Koku, can come and help me lift some heavy engine parts. Mr. Damon wants to explain something to me."
"Ha! Nothing what so heavy Koku not lift!" boasted the giant.
"Go on! Lift yo'se'f 'way from heah!" muttered Eradicate as he picked up his dropped spade. And then, with a smile of satisfaction, he fell to work in the mellow soil while Tom led Koku to one of the shops where he set him to lifting heavy motor parts about in order to get at a certain machine that was stored away in the back of one of the rooms.
"That will keep him busy," said the young inventor. "And now, Mr. Damon, I can listen to you. Do you really think you have a new idea in airships?"
"I really think so, Tom. My Whizzer is bound to revolutionize travel in the air. Let me tell you what I mean. Now cast your mind back. How many ways are now used to propel an airship or a dirigible balloon through the air? How many ways?"
"Two, as far as I know," said Tom. "At least there are only two that have proved to be practical."
"Exactly," said Mr. Damon. "One with the propeller, or propellers, in front, and that is the tractor type. The other has the propeller in the rear, and that is the pusher type. Both good as far as they go, but I have something better."