bound hand and foot, and were preparing to carry him toward the fire
when there came a startling interruption to their plans.

With a roar as if the desolate mountains about them were toppling
about their ears one of the dynamite bombs carried by the boys was
dropped and exploded a short distance from the camp. A huge hole was
torn in the earth and a great cloud of dust arose.

Shrieks and cries filled the air and, although none of them was hurt,
the Patagonians rushed about like ants when some one has stirred up
their nests. Suddenly one of them happened to look upwards and gave a
wild yell.

Instantly the tribesmen, without waiting to pick up any of their
possessions, fled for their horses and mounting them rode out of sight
without daring to look round. To accelerate their progress the boys
sent another dynamite bomb and two rockets after them, and then
descended to pick up the professor who, bound as he was, had been left
on the ground and was quite as much in the dark as to what he owed his
escape to as the Indians were.

"Oh, boys!" he exclaimed, as the machine glided to earth and the boys
stepped out, "you were just in time. I really believe they meant to
make soup out of me. They were worse than the electric ray, a great
deal. Oh, dear, I wish I had obeyed Captain Hazzard, but I wanted to
get a specimen of a Patagonian dog-flea. They are very rare."

"Did you get one?" asked Frank, laughing in spite of himself at the
woe-begone figure of the professor, who, his bonds having been cut,
now stood upright with his spectacles perched crookedly on his nose.