Chapter VI: Real Progress!

After going on duty that night, Johnny came upon Samatan, leader of the boat's native crew. He was seated in a corner, but one of the ship's lamps lighted his face. He was staring at the steel ball and there was unmistakable animosity in his expression.

"Looks as if he'd like to eat it," Johnny mused. "Wonder what it's all about."

A little later he heard the natives talking in their quarters below deck.

"Sounds as if they were angry about something," he told himself. More than once he heard Samatan's voice rising above the rest, as if he were making some sort of speech. He wondered if it could be possible that the European spies had somehow inspired these natives with hate for _all_ Americans.

"That would be bad," he thought. "It might spell disaster." He resolved to cultivate Samatan's acquaintance to find out, if possible, just what his grievance was. Then he might put things to rights.

Maybe some superstition is connected with the steel ball, Johnny reflected. When you are among primitive people you never know quite what to expect.

That night the green arrow blinked again. Johnny saw it, shortly after midnight. The boat was closer in, now, and he could make out the separate lights of the arrow as they flashed, up there on the hillside. If there was another light out at sea, it must have been far away--or too low to be visible. He caught no sight of it.

When the arrow appeared, Johnny got busy at once. With small circles, like coins in a row, he sketched an arrow, in pencil.

From the tip of the flashing arrow to the other end, there were thirteen lights. Besides, there were two lights slanting back on each side, at the tip. These four helped form the head of the arrow. Four others, in pairs, made the feather end.

As he watched intently through powerful binoculars loaned him by the professor, Johnny noted that the thirteen lights blinked separately, but the eight which comprised the head and feather of the arrow, blinked in unison.

"Those eight lights must stand for a period," he concluded. "The thirteen are letters, or code numbers. I wonder how they work."

For some time, as on that other occasion, Johnny recorded the winking and blinking of the lights. When at last the green arrow became dark, he took a turn about the deck, then settled down to the task of trying to figure that code. Dawn found him still figuring, but seemingly no nearer the solution.

"Dumb!" he exploded at last, as he crammed the notebook into his pocket and went to breakfast. When he returned to the deck late that afternoon he found Doris and Dave working over some notes.

"Hello, Johnny. How about those pictures we took yesterday?" It was Dave who spoke.

"Oh, yes," Johnny exclaimed. He had forgotten them. "Come on to the darkroom, if you like. I'll develop them right away."

Doris accompanied them to the darkroom. There, fascinated, they watched strange creatures of the depths come out on the film.

The great, shadowy creature which had peered out from a rocky cavern was, the picture revealed, a veritable deep-sea monster.

"If only I could bring him up!" Dave exclaimed. "But then, he'd never live at surface levels. But our great, sea-green octopus, I do believe, could live anywhere. I'm going after him!"

Most interesting of all--and most baffling--was the picture Johnny had taken of the great, slow-moving thing seen in the open water far from the rocks.

"Oh, that!" exclaimed Dave, as it began coming out in the film, "that's really a monster for you!"

"If it _is_ a monster," said Johnny, in a tone of mystery.

Whatever it might be, the picture only added to the mystery. Too far away, too indistinct to be seen clearly, the thing might have been a whale, or some other form of deep-sea monster. Truth was--deep down in his heart Johnny believed it to be neither. His theories were too fantastic to be put into words--at the moment.

* * * * * * * *

Their afternoon ashore the following day proved interesting, inspiring, and exciting.

They were served a grand meal of native wild turkey, baked sweet potatoes and all manner of delicious, tropical fruits. After that, Mr. Kennedy took Dave, Doris and the professor for a look at some unusual wild birds, nesting at the edge of the jungle.

Johnny settled himself comfortably in a split-bamboo chair and gave himself over to wondering and dreaming.

Mildred had gone to supervise the washing of her precious dishes--some of which dated back to ancient buccaneer days--so Johnny was alone with his thoughts. And strange thoughts they were.... He recalled having heard the bearded giant Kennedy saying to the professor--too much absorbed in research to pay much attention--"Those men, those Europeans! They starve their own people, and use the money to buy gunboats and cannon. They are slaves--those people--slaves! If we don't watch out _we'll_ be slaves, too!... Look at this Caribbean Sea! More important than the Mediterranean ever was! And who's to stop them from taking possession of these islands? Why, even the president of this poor little Republic is in debt to them! Up to his ears!"

Was Kennedy right? Johnny wondered, dreamily. What of that signal up there on the ridge--the signal of the green arrow? Was _it_ operated by spies? And if so--what had they been saying with those blinking lights? What--

"Penny for your thoughts!" Mildred was back.

"Not worth it." Johnny stood up. "Tell you what, though--I'll play you a game!"

"What sort of game?"

"Game of the Green Arrow. The object is to discover what it says!"

Drawing up a small table, Johnny spread a notebook and some papers on it.

"Now," he said. "Here's a drawing of the green arrow. Twenty-one green lights make the arrow. Thirteen in a row," he pointed out, "two here, two there, and two more on each side at the other end. The last eight blink all at the same time, but the thirteen--only one at a time. By their blinking they are conveying messages. But what do they say? Here's a set of papers with records of their blinking, all marked with numbers. If you can work that out, you go to the head of the class!"

"I see. Easy as that!" Mildred laughed, and promptly seated herself across from him.

After that, save for the lazy hum of bees or the sudden whir of humming birds' wings, there was silence in the place....

Suddenly the girl sprang up. "Why, I--I've got it!" she cried, excitedly.

"Just like that!" Johnny smiled.

"Well, I certainly have! Listen! This is what that first message says:

"_Keep a sharp lookout. There are counter-spies afloat._"

"WHAT! Gee willikens!" Johnny gazed at her, truly amazed. "How could you make it read like that?"

"Because that's the way it _does_ read!" she raced on. "It's really easy. There are twenty-six letters in the alphabet. Having thirteen lights suggests that they have split that twenty-six _in two_. Each light must stand for _two_ letters. But the question is--which two? Well, the _top_ thirteen stand for A, B, C, etc. But what about the bottom ones?

"The simplest way," she leaned forward, smiling, "would be to put the _last_ thirteen letters under the _first_ thirteen! Then, blinking _one_ light for _two_ letters, let the fellow receiving the message see _which_ of the two letters makes sense.

"I tried that," she went on "and it didn't make any sense at all, so I ran the _last_ thirteen, backwards. By trying each of the two possible letters in each instance, I got the message I just read to you."

"Which must be just about right," Johnny breathed. "Mildred--you're a wonder! Now let the old green arrow blink! We'll always know what it's saying--and we may make some startling discoveries." With that he seized her hands and whirled her wildly about the broad porch.

"List--listen," she panted, as, quite out of breath, she dropped into a chair, "what's that?"

"Natives singing, I suppose" said Johnny, "they are fond of singing."

"Those singers are not natives!" The girl held up a hand for silence. "They never sing like that. Besides--all those voices are men's!"