The last of the stores, provisions and supplies were put in the big car of the airship, a route had been carefully mapped out, and Tom, after saying good-bye to Mary Nestor, his father, the housekeeper, and Eradicate, took his place in the pilot house of the airship one pleasant morning at the beginning of Summer.
"Don't you wish you were going, Rad?" the young inventor asked, for the colored man had decided to stay at home.
"No indeedy, Massa Tom," was the answer. "Dat's a mighty cold country in Shebeara, an' I laik warm wedder."
"Well, take care of yourself and Boomerang," answered Tom with a laugh. Then he pulled the lever that sent a supply of gas into the big bag, and the ship began to rise.
"I guess we've given those spies the slip," remarked Ned, as they rose from the ground calling good-byes to the friends they left behind.
"I hope so," agreed Tom, but could he have seen two men, of sinister looks, peering at the slowly-moving airship from the shelter of a glove of trees, not far off, he might have changed his opinion, and so would Ned.
Then, as the airship gathered momentum, it fairly sprang into the air, and a moment later, the big propellers began revolving. They were off on their long voyage to find the lost platinum mine, and rescue the exile of Siberia.