loaded into the aeroplane. But here an unanticipated difficulty
manifested itself. Obviously the aeroplane would be too heavily
laden if she attempted to carry all or even a good part of the
ivory.

"Now we are stuck," cried Harry.

"Hold on," exclaimed Frank with a smile, "I anticipated this. We
are going to turn the Golden Eagle into a tow-boat."

"A tow-boat?"

"That's what I said."

"What do you mean?"

Frank, in reply, bent over the stem-locker of the aeroplane and drew
out what Harry instantly recognized as the silk envelope of an
experimental dirigible they had built the year before.

"Now then," said Frank, "give a hand here."

They all three pulled and hauled till the envelope was spread level
on the ground, all folds and creases having been carefully shaken
out.

"Well," said Harry, "this would carry an awful weight of ivory, but
how are you going to inflate it?"

"With these cylinders," was the answer as Frank opened the