Paula waited. The whistling noise went on. It was vaguely discordant, and it was monotonous, and it was more than a little irritating. Again it changed timbre, going up to the shrillest of squealings, and back nearly to its original sound an instant later.

Bell began to paw over maps. The plane had been intended for flight over the vast distances of Brazil, and there was a small supply of condensed food and a sporting rifle and sh.e.l.ls included in its equipment. Emergency landing fields are not exactly common in the back country of South America.

"Here," said Bell sharply. "Here is where we are. It must be where we are! No towns of any size nearby. No railroad. No boat route. Nothing!

Nothing but jungle shown here!"

He frowned absorbedly over the problem.

"What is it?" asked Paula.

"Someone near," said Bell briefly. "That's another radio receiver, an old fashioned regenerative set, sensitive enough and reliable enough, but a nuisance to everyone but its owner--except when it's a G.o.dsend, as it is to us."

The music ended, and a voice announced in laboriously cla.s.sic Portuguese, with only a trace of the guttural tonation of the _carioca_, that the most important news items of the day would be given.

Paula paled a little, but listened without stirring. The voice read--the rustling of sheets of paper was abnormally loud--a bit of foreign news, and a bit of local news, and then....

She was deathly pale when the announcement of her father's death was finished, and she had heard the official view of the police reported--exactly what Ribiera had told her it would be. When the voice added that a friend of the late Minister of War, the Senhor Ribiera, had offered twenty contos for the capture of the fugitive pair, who had escaped in an airplane stolen from him, she bit her lip until it almost bled.

"I know," he said abstractedly. "It's as you said. But listen to that whistle."

The news announcement ceased. Music began again. The whistling abruptly died away.

"I just found some coils," said Bell feverishly, "that plug in to take the place of the longer-wave ones. I'm going to try them. It's a hunch, and it's crazy, but...."

There were sharp clickings. The radio receiver was one of those extraordinarily light and portable ones that are made for aircraft. In seconds it was transformed into a short-wave receiver. Bell began to manipulate the dials feverishly. Two minutes. Three. Four.

The speaker suddenly began to whine softly and monotonously.

"Regeneration," said Bell feverishly, "on a carrier-wave. It can't be far off, that receiving set."

Suddenly a voice spoke. It was blurred and guttural. Infinitely delicate adjustments cleared it up. And then....

Bell listened eagerly, at first in triumph, then in amazement, and at last in a grim satisfaction. Reports from Rio on a short-wave band of radio frequencies were pa.s.sing from Ribiera to some other place apparently inland. It was Ribiera's own voice, which quivered with rage as he reported Bell's escape.

"_I do not think_," he snapped in Portuguese, "_that full details should be spoken even on beam wireless. I shall come to the_ fazenda _to-morrow and communicate with The Master direct. In the meantime I have warned all sub-deputies in Brazil. I urge that all deputies be informed and instructed as The Master may direct._"

Another voice replied that The Master would be informed. In the meantime the deputy for Brazil was notified.

This list of bits of information chilled Bell's blood. This man, of Venezuela, had been denied the grace of The Master by the deputy in Caracas. He would probably use the pa.s.swords and demand the grace of The Master of sub-deputies in the State of Para. To be seized and Caracas informed. The deputy in Colombia desired that the son of Colonel Garcia--upon a hunting-party with friends in the Amazon basin--should be attached to the service of The Master. His father had been so attached, and it was believed had smuggled a letter into the foreign mail warning his son. If possible, that letter should be intercepted. And from Paraguay the deputy requested that the family of Senor Gomez, visiting relatives in Rio, should be induced to regard the service of The Master as desirable....

The orders ceased abruptly. Ribiera acknowledged them. The whining whistle cut off. And Bell turned to Paula very grimly indeed.

"Pretty, isn't it?" he asked in a vast calmness. "Apparently every nation on the continent has some devil like Ribiera in charge of the administration of this fiendish poison. Every republic has some fiend at work in it. And they're organized. My G.o.d! They're organized! The Master seems to supply them with the mixture of poison and its antidote, and they report to him...."

Paula nodded.

"That was what my father had written down for you," she said quietly.

"Any man who can be lured to eat or drink anything these men have prepared is lost. He gains no pleasure, as a drug might give. He is entrapped into a lifetime of awful fear, knowing that a moment's disobedience, a moment's reluctance to obey whatever command they give, will cause his madness."

"I'm trying to think what we can work out of this," said Bell shortly.

"Some things are clear. There's a radio receiving set nearby, which listened to those short-wave reports. Within five or six miles, at most. We're going to find that to-morrow. And there's a central point, a _fazenda_, where one may talk direct with The Master, whoever and wherever he may be. And--judging by Ribiera--my guess is that The Master has the same hold upon them that they have on their underlings.

Ribiera is too arrogant a scoundrel to make obsequious reports if he were not afraid to omit them." He was silent for a moment, thinking.

Then he said abruptly, "Try to get some sleep, if you can. That pistol of Ribiera's--you have it handy? Keep it where you can reach it in the dark. I'm going to watch, though."

Paula settled herself comfortably, and looked queerly across the dimly lit little cabin at him.

"My friend," she said with the faintest of quavering smiles, "Please do not rea.s.sure me. I have the courage of endurance, at least. And--I do not fear you."

It seemed to Bell, listening in the darkness that fell when he turned off the switch, that she stayed awake for a long time. But when she did sleep, she slept heavily.

Bell had a raft of canes afloat beside the amphibian when she waked.

He was sweat-streaked and bitten by many insects. He was tired, and his clothes were rags. But the raft was nearly twenty feet long, it would easily float two persons and what small supplies the plane carried, and it could be handled by a long pole.

"Hullo," he said cheerfully when she climbed on top of the waterlogged hull of the plane. "We're nearly ready to start off. I'm sorry I can't advise you to try to refresh yourself in the river. There are some fish in it that are fiends. One of them took a slice out of the side of my hand."

"_Piranhas!_" she exclaimed, and was pale. "You should have known!"

_Piranhas_ are small fresh-water fish of the Brazilian rivers, never more than a foot and a half long, which prove the existence of a devil. Where they swarm in schools they will tear every morsel of flesh from a swimmer's body as he struggles to reach sh.o.r.e, and leave a clean-stripped skeleton of a mule or horse if an animal should essay to swim a stream.

"I'll ask, next time," said Bell ruefully. "I'd planned a swim. But if you'll fix some coffee while I finish up this raft, we'll get going. I don't think we're far from some place or other. I heard what sounded suspiciously like a motor boat, about dawn."

She looked at him anxiously.

"Of course," said Bell, smiling, "if the boat belonged to whoever listened in on the Rio broadcast _and_ the short-wave news, he won't be especially friendly, though he should be glad to see us. But I've been studying the map, and I have a rather hopeful idea. Let's have coffee."

He grinned as long as she was in sight, and when he went into the cabin of the plane he seemed more cheerful still. But the idea of floating down this nameless little jungle stream upon a raft of canes was not one that he would have chosen. It was forced upon him. To travel through the jungle itself was next to impossible with a girl, especially as they were dressed for city streets and not at all for battling with dense and thorn-studded undergrowth. And to stay with the plane was obviously absurd. Sooner or later they had to abandon it, though the moment they did desert it they would be encountering not only the impersonal menace of the jungle, but the actual enmity of all the human race. The raft was the only possibility.

It floated smoothly enough when they started off, with Bell working inexpertly with his long pole to keep it in mid-stream. He was, of course, acutely apprehensive. In country like this a rapid could be expected anywhere. The jungle life loomed high above their heads on either side, and the life of the jungle went on undisturbed by their pa.s.sage. Monkeys gaped at them and exchanged undoubtedly witty comments upon their appearance. Birds flew overhead with raucous and unpleasant cries. Toucans, in particular, made a most discordant din.

Once they disturbed a tiny herd of peccaries, drinking, which regarded them pugnaciously and trotted st.u.r.dily out of sight as they came abreast.

But for one mile, for two, the stream flowed smoothly. A third.... And Paula pointed ahead in silence. A dug-out projected partly from the sh.o.r.eline. Bell wielded his long pole cautiously now, and drew closer and ever closer to the stream bank. Paula pointed again. There was even a small dock--luxury unthinkable in these wilds.

The raft touched bottom. And suddenly from somewhere out of sight there came a horrible and a b.e.s.t.i.a.l sound. It was a scream of blood-l.u.s.t, of madness, of overpowering and unspeakable rage.

Following it came cackling laughter.