In the hot sun the balloon bag expanded quickly. At length the bag was almost full.
"Everything ready?" cried Jack, at length, when all were on board.
"Ready," said Tom at the engines.
"Then off we go!"
Tom pulled the clutch lever and the propellers whirled. Jack gave the steering and controlling wheel an impulse and like a huge bird the Wondership shot up. But she rose slowly, for besides the unusual number of passengers, she was also carrying a great weight in supplies.
As the craft rose three figures watched it from under the concealment of a clump of mesquite.
"There they go, boys," said Masterson, for it was he and his two cronies.
"Yes, they're off for Rattlesnake Island," sneered Eph. "I hope they get bitten."
"I'll bet they don't dream that we know everything about their plans," chuckled Sam. "I'd like to get even with that red-headed kid."
"Well, you'll get a chance before long," declared Bill Masterson. "I don't see that there's any use in hanging around here any longer," he went on. "The thing to do now is to get our boats and go down the river."