Ned headed them off running toward the west edge of the crater. All at
once a new note sounded. With an unearthly howl Ned Rector disappeared.
They heard his voice growing fainter, too, just as Stacy's had done.

"They've fallen in!" cried Tad.

"Everybody stand still!" commanded Dad.

Recognizing that he was right, the others obeyed, with the exception of
Tad Butler, who crept cautiously forward, feeling his way with the toes
of his boots, that he too might not share the fate of his two companions.

Dad, from somewhere about his person, produced a bundle of sticks which
he lighted. He was prepared for just such an emergency. A flickering
light pierced the deep shadows, just enough to show the party that two
of their number had disappeared.

"There is the place," cried Tad. "It's a hole in the ground. They've
fallen in."

"Chunky's always falling in," laughed Walter half hysterically.

With his rope in hand, Tad sprang forward.

"Light this way, please," called Butler. "Hello, down there!" he cried,
peering into the hole in the ground.

"Hello!" came back a faint answer from Ned Rector. "Get us out quick."

"What happened?"