Part 17 (1/2)

It was the voice of the mountain once more.

With yells of dismay and terror the remainder of the gorilla band instantly dashed up the rocky mountain-side dragging with them, in grotesquely human fas.h.i.+on some of their wounded. Several of these, however, still lay on the ground and the boys put them out of their misery with a few well-directed shots. A pathetically human look lingered in the eyes of some of the injured gorillas and Harry burst out with:

”This is awful work. I'd rather fight a dozen bands of cannibals than have to do this.”

”And yet,” replied Frank, ”if we hadn't killed them they'd have killed us.”

At last the unpleasant work was over and the ivory was rapidly loaded into the aeroplane. But here an unantic.i.p.ated 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 antic.i.p.ated 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 store-room below the floor of the Golden Eagle and pointed to a dozen cylindrical steel receptacles. ”They contain more than enough pure hydrogen gas at a high pressure,” he explained, ”to inflate the bag.”

In his enthusiasm Harry waved his helmet and Ben did the same.

”An aerial express, hurray!”

The inflation hose was soon connected to the first of the cylinders and with a hiss the gas rushed into the bag when a turn of the wrench set free the precious stuff. Slowly the big yellow envelope swelled and a.s.sumed shape until by the time the last cylinder was empty it was tugging and straining to rise. But the boys had weighted it down with rocks and pegged its net ropes to the ground.

The ivory was loaded into a sort of rope basket, like those used to hoist cargo aboard a s.h.i.+p, and in a short time, so quickly did they work, they were ready for the air, so far as what Harry called ”the airbarge” was concerned.

”We shall have to strip the Eagle,” decided Frank, when the inflation job was finished.

”Of everything that we can spare,” added Harry, setting to work at once to rip the transoms and detach the bolts that held the heavy wireless apparatus in place. As he did so, Frank was moved by a sudden thought.

”Hold on a second, Harry,” he shouted, ”I'll call up the river camp before we cut off all communication.”

Rapidly he sent out the call. Again and again his nervous finger agitated the key--but there was no response.

”They--they don't answer,” gasped Frank at last--heavy anxiety in his tones.

”Oh, Frank, do you think anything serious is the matter?” cried Harry.