put in the small cannon, together with the primer. Then the wires were attached to it, and extended off for some distance.
"But we won't attach the battery until the last moment," Tom said. "I don't want a premature explosion."
The projectile was also put in, and Tom once more looked to see that the armor plate was in place. Then he adjusted the various gauges to get readings of the power and energy created by his new explosive.
"Well, I guess we're all ready," he announced to his friends. "I'll hook on the battery now, and we'll get off behind that other hill. I had Koku make a sort of cave there—a miniature bomb-proof, that will shelter us."
"Do you think the blast will be powerful enough to make it necessary?" asked Mr. Damon.
"It will, if this larger quantity of explosive acts anything like the small samples I set off," replied the young inventor.
The electric wires were carried behind the protecting hill, whither they all retired.
"Here she goes!" exclaimed Tom, after a pause.
His thumb pressed the electric button, and instantly the ground shook with the tremor of a mighty blast, while a deafening sound roared
