Then pulling the transmitter toward him, he began to reply. This two-way set for both transmitting and receiving was of the boys’ own design. Simpler, more compact, than any device turned out by the great companies manufacturing radio supplies, it had served them well in other lands and climes and in the most perilous of circumstances had proven their staunchest support. The impact of the voice against a sensitive diaphragm acted to automatically close the receiver. It was this which constituted the chief feature of the device, making the jump from transmission to reception and vice versa a matter of no account at all.

Bob and Frank, unable to hear what Mr. Hampton had to say, but listening to Jack’s remarks, gathered the drift of the conversation. As Frank had surmised, the main party had been so delayed in pushing down river through the jungle growth along the bank that only a couple of miles had been made. Then, finding no trace of the runaway raft, Mr. Hampton had returned to their old camp site and obtained the radio which had not been set up for some days. Rigging it up with Niellsen’s aid, he had at once begun calling. When no reply was received, he had continued to call at fifteen-minute intervals. And it was one of these calls which had caught Jack’s ear.

Jack was outlining their situation on the island to his father. And after having heard how matters stood, the latter apparently, so far as Bob and Frank could gather from Jack’s replies, was of their opinion regarding a method of rescue. Consequently, he intended again to essay the crossing of the river at the old camp site, after which he would make his way down the right bank which was higher ground and freer of jungle growth to the point opposite the island where the boys believed a swimmer could cross the channel with a rope.

Finally, Jack closed communication and turned to his comrades. Relief at this quick opening of communication with the main party was uppermost in the minds of all. Once more they had reason to be thankful that radio was at their command.

“And a mighty good thing, too,” said Jack, “that we took Frank’s advice, and split our equipment, so that both Dad and ourselves are supplied.”

The attempt at rescue, however, could not be made until the following morning. The better part of the day already was sped. Mr. Hampton would spend the balance in crossing the river and starting downstream. He might, of course, reach a position opposite them before nightfall, as four hours of daylight yet were left. But the crossing could not be attempted except in daylight and so he would have to wait until the following day.

At length, after turning the matter over and considering it from all angles, the boys decided to go ashore and prepare some food. They had not eaten since their early morning breakfast. Matse, accordingly, was aroused and sent to stir up the bearers. A case of tinned foods was opened, and the boys tossed materials for a meal to the bearers on shore.

CHAPTER XV
RESCUED

Not until shortly after dusk that night was Mr. Hampton heard from. Then a hail from the right bank of the river near the head of the island was heard by the boys who had taken up their position about a fire, for the night had become chilly. Calls sounded back and forth across the water. Finally, assured of each other’s safety, both parties retired for the night, prepared to attempt the work of rescue as soon as dawn should bring sufficient light.

Bob as the strongest swimmer of the three boys was eager to make the crossing. But two obvious enough reasons were adduced to make him abandon the idea. In the first place, the boys did not possess rope. That Mr. Hampton had, and it would have to be carried to the island by a member of his party. In the second place, even though the current in the right hand channel was less swift than the other side of the island, yet a swimmer setting out for shore from the tip of the island would be hard put to it to escape being carried down stream into the rapids. On the other hand, a swimmer taking to the water from the river bank at a point considerably above the island, could count upon making the crossing in safety. Moreover, he would have the rope from shore and, if he became endangered, his comrades could pull him to safety.