They unreeled the long wire antenna and removed the lead weight, or “fish,” from the end, replacing it with a bottle from the emergency kit. In flight the purpose of the fish was to keep the wire trailing out behind as straight as possible; but now they stretched the slender braided metal thread to the top of a tree near the river and tied the bottle to the highest branch. In this manner a message could be flashed into space, they did not know how far, but none could be taken in answer, as there was no receiving equipment in the plane.

Ted switched on the battery and placed his fingers on the key.

“S. O. S., S. O. S.,” the spark was flashed into the ether; “stranded one hour north of Cuzco, in valley surrounded by ring of yellow vapor. Need propeller. Notify aviation-field, Cuzco.”

The message was repeated a number of times.

“We are wasting time and energy,” Ted said suddenly, releasing the key and cutting the switch. “In the first place, I doubt if the spark will carry beyond the valley. And I just remembered that even if they should pick it up at the flying-field, they could not possibly help us. There is no other ship in commission, and even if there were, the only persons who could handle it are the lieutenants, who certainly would not come to help us.”

“I don’t look for help from the field, but I thought there might be a station somewhere near here in the mountains, a secret government outfit. And if the facts were known, it might be possible that a ship would be sent from some other camp, perhaps even from Bolivia.”

“All right. I’ll send it again and add our names to the end of it.”

Once more the appeal was wafted into space.

“I have it,” Ted shouted, jumping from his seat. “We will get a new stick right here!”

“Get one here?”