The days that followed were busy ones. There were shots for typhoid, smallpox and all the rest, with many a sore arm.

They marched until their legs ached and their feet were sore, but all the time their officers were so kind and all their companions so friendly that it did not seem to matter.

Long hours were filled with classes. They learned history of the Navy from the beginning, a glorious story of which they could all be proud. Navy customs came in for their full share of discussion.

“Boy, am I glad I am getting this first!” Sally exclaimed one day. “Without it I’d be completely lost aboard a ship.”

“But we’re not sailing on a ship, at least not the way things stand now,” said Nancy.

“All the same we’re going in for Communications and you can’t communicate with anyone unless you speak his language,” Sally laughed.

“You’ve got something there,” Nancy agreed.

As for Barbara, besides her regular assigned work, she was taken to an airfield where paratroopers were being trained.

As she watched ten boys, one by one, slip from a captive balloon hundreds of feet in the sky, she exclaimed:

“Oh! I could never do that!”

When she saw the parachutes, white against a blue sky, come drifting down and watched the boys drop to the ground as if they were dead, then spring up laughing, she exclaimed:

“That’s wonderful! I’ll do anything, just anything to have a part in that!”

For a time the two black boxes were neglected. Then, one night, they came back with a bang. That was the night following the receipt of a letter from Sally’s old friend, C. K. It ran:

“Dear Sally: Received yours of the 17th. Note what you say about the black boxes.

“Your recent discovery may be of the greatest importance. I refer to the disturbances you think may be messages in code. On that wave-length it can hardly be anything else. Keep it up. You may make a startling discovery. I have definite theory regarding those supposed messages, but will not tell you about it until you have further details.

“You don’t know how to receive in code, do you? It’s not difficult. Get someone there to teach you.

“I agree with you that an outside aerial will help bring out the sounds. But don’t take too many chances just to make an old man’s dream come true.

“Too many chances!” Sally exploded after reading the letter. “There couldn’t possibly be too many chances.”

That very night she started taking the chances.

It was a cloudy, windy night. “Just the night for a murder,” Sally whispered to Nancy as they embarked on their enterprise.

“Or something,” Nancy agreed.

It was Saturday. All the WAVES have Saturday afternoon and night off for shore leave. Most of them would be away so there would be few prying eyes. That was why they had picked on this night for connecting the black boxes with the aerial set up on the roof.

The wires running from Sally’s room up to Nancy’s and to the attic were in place. The lock to the attic door was old. Nancy had solved that with a skeleton key bought at the five and ten.

“There’s no counting of noses at bedcheck tonight,” Sally said. “So we’ll start work at ten. You can be the lookout and I’ll do the work.”

“Don’t forget you’re going to be quite a way up in the air,” Nancy cautioned.

“Oh, I’ve always been a tomboy.” Sally did a cartwheel. “I’ll put on gray slacks and a gray sweater, just in case the moon comes out. The roof is gray, you know.”

“You’d better wear sneakers.”

“Oh, sure!”

And so everything was set for the hour of ten.

“All clear!” Nancy whispered, tiptoeing down the hall. “Deck Three is deserted. Come on up.”

Armed with two pairs of small pliers, a coil of wire, a flashlight and the key to the attic, Sally followed in silence to the floor above. A swift glide, the rattle of a key, the silent opening and shutting of a door and Sally found herself tiptoeing up the attic stairs.

It was a dark and gloomy spot, that attic. As Nancy had put it: “A hundred years look at you up there.”

This was true, for an accumulation of furniture, long outmoded, was stored there. There, too, were all manner of stage drops and settings left over from amateur plays. With her flashlight aimed low, Sally picked her way with care to the nearest gable window.

The window was nailed down but her pliers soon took care of that.

As she stepped out on the roof, clinging to the gable, she took one good look at the world beneath and above her, then shuddered.

With dark clouds rolling through a black, windy sky it was one of those nights that always seemed to depress Sally.

Shaking herself free from her moodiness, she gave close attention to the problem that lay before her.

To discover the end of a wire they had thrust up along the heat pipe and to attach the end of her coil to it was simple enough. From there it was to be a trifle difficult. The roof was not too steep but shingles do not offer much chance for a hand grip. As Nancy had said, it was quite a distance to the ground from there and, though she would not have admitted it for worlds, Sally found herself a little dizzy.

One fact gave her a little comfort. Just beneath the part of the roof where she must do her climbing was an elm tree. Its top was broad and its strong, flexible branches all but brushed the building.

As she stood there hesitating, a group of freshman boys came marching by, singing.

Flattening herself against the gray roof she waited for them to pass. Then, having steeled herself for her task, she thrust her tools into her pockets, held the loose end of the wire in her teeth and began to climb. Clutching with her hands and pushing with her feet, she crept upward. She made slow progress. Now the ridge seemed not so far away. She dared not look back or down.

She was halfway up, when, with startling suddenness, the moon came from behind a cloud.

“Gosh!” she exclaimed, flattening herself against the shingles. She went so flat that she started slowly to slide. After digging in with toes and fingers she managed to hold her ground. And then the moon hid its face.

One more desperate struggle and she found herself sitting triumphantly astride the ridge.

“Now,” she breathed, “all I have to do is to pull the wire tight, attach it to the aerial and then slide down.”

Yes, that was all there was to it, just to slide down.

With fingers that trembled slightly she drew the gray wire tight against the roof, cut it at the right place and then, with the skill of a lineman, wound it tight, round and round the original wire leading to the aerial.

She had twisted herself back to a place astride the roof when again the moon showed its face.

At the same instant she thought she heard someone far below let out a low whistle. She couldn’t let herself be seen sitting there, just couldn’t. That might mean catastrophe.

Then it happened. In attempting to throw herself flat, she overdid the matter. Missing a grip on the ridge, she heard her flashlight go rolling down the roof. And, in quite an involuntary manner, she came gliding, clawing and kicking after it.

Recalling the tree and at the same time realizing that she was powerless to check her slow glide, she managed somehow to swing half about. When she left the roof, she rolled off, felt the brush of a leafy branch, struck out desperately with her hands, gripped a branch, clung there and found herself at last dangling in mid-air. Or was she two-thirds of the way down? There was no way of knowing.

Clinging desperately to the cracking branch, she dared not call for help. What was to be done? Feeling a larger branch against her back, she tried to turn about. She had made half the swing just as her slender branch gave an ominous crack.

At the same time a voice from below said: “Come on down, sister. I’ll catch you.”

“Good grief!” she thought. “It’s a man.” And then the branch broke.

She landed rather solidly in a pair of strong arms. Then her feet hit the ground. Also the moon came out.

“What were you doing up there?” The man held her, as if she were a sack of wheat that might fall over.

The moonlight was on his face. He was young and wore a heavy blue coat. His cap had been knocked off.

“That,” she replied slowly, “is a military secret. But the way I came down, it seems, is common knowledge.” She did not try to escape.

“Rather uncommon knowledge, I’d say,” he drawled. “You might have broken your neck.”

“Yes, or been caught.”

“You were that,” he chuckled. “And you’re not a bad catch, at that. This is a rather lonesome college for some folks. Tell me who you are and I’ll let you go.

“I will anyway,” he said dropping his hands.

“I’m Sally Scott and I’m a WAVE!” she confessed.

“A WAVE! Then we belong to the same outfit. I’m a flying sailor. Shake!” He put out a hand for a good handclasp.

“Oh! A flying sailor!” she exclaimed. “Then you could teach me to receive in code.”

“Certainly I could and will, in my spare time.”

“We have an hour after supper.”

“Suits me. But, say, now that I have you, how about a coke and a chat somewhere?”

She did not reply at once. “We—we have to be careful. Mind taking my pal along?”

“Not a bit.”

“Then it’s a go. I—Oh, boy! Nancy will think I’m dead, or something! Wait. I’ll be back.”

“I’ll wait.”

She was gone.

“Sally Scott! How did you get down that way?” Nancy exclaimed as Sally came racing up the second story ladder, instead of coming down from the attic.

“I—I found a new way to get down and, and I found a nice new boy,” Sally panted. “He wants to buy us a coke. Come on, let’s go.”

“Sally, you didn’t,” Nancy protested. “Besides, there’s a scratch on your face. It’s bleeding.”

“All right then, I didn’t.” Sally dabbed at her cheek. “You won’t believe me if I tell you the truth.”

“Try me.”

“All right then, after I got the wire all fixed. I fell off the roof, landed in a tree and hung to a branch as long as I could and what do you think?”

“A nice boy caught you. And you expect me to believe that?”

“All right, then don’t. Anyway the wire is up.”

“And now we can get London, Paris, and Berlin. Come on. Let’s try.”

“No,” Sally seized Nancy’s arm. “The nice boy is real. Come on, let’s go.”

“You wouldn’t go looking like that?”

“I’ll wash the blood off my face. We’ve got to get in uniform. Must wear them even off duty, you know!”

So Sally was off to the washroom to bathe her cheek.

“Now I ask you,” Nancy challenged the empty air, “how can they hope to make a WAVE out of a girl like that?”

Sally was back in a minute and slipped into her uniform. Nancy was ready a moment later and then they were down the stairs and out into the night.

“This is Nancy McBride.” Sally introduced her companion to the flying sailor who had stepped out into the moonlight.

“I’m pleased to meet you, Nancy. I’m Danny Duke,” he said. “Distant relative of the famous Dukes, so distant that they never even sent me a package of Duke’s mixture. Do you also walk in your sleep? And may I be looking for you on the roof tops?”

“Sally wasn’t walking in her sleep,” said Nancy, “but tell me, did she really fall off the roof and did you catch her?”

“Shall I tell her?” Danny turned to Sally.

“Sure. Tell her. She wouldn’t believe me.”

“Well, then,” said Danny, in a mock-solemn voice, “it’s really true. I made a real catch that time. But then, the elm helped out a lot.”

“Good old elm!” Sally exclaimed. “I’ll never forget it! And now,” she added, “I feel in need of reviving.”

The reviving came with good steaming cups of coffee.

Danny Duke could stand the glare of a neon light, Sally found as she looked at his strong, friendly face.

“I’m just past twenty,” he told them with a touch of boyish pride. “And my training is about finished right now.”

“How is it you’re here so far from the Navy flying schools?” Nancy asked.

“I was back on some math, so they sent me here to brush up. I’ve about got it now. Another two weeks will do it.”

“Too bad,” Sally sighed. “But that will be time enough to teach me to receive code, won’t it?”

“Oh, sure,” Danny grinned. “But say, are you the practical young miss! Here I save your life, and first thing you insist that I do something more for you.”

“It’s not for me.” Leaning across the table Sally allowed her voice to drop. “It’s much more important than that, I hope. It’s for our old friend Uncle Sam. The things I did up there on the roof are part of it, just as my learning code will be. You are such a nice boy, I want you to have a part in it.”

“Well, thanks—” Danny was visibly embarrassed. “Thanks a lot: I’ll help all I can.”

The truth is that Danny was to have a much greater part in the undertaking than either he or Sally knew.

“And now for one more try at the two black boxes,” Sally whispered excitedly after the girls had said good-bye at the gangplank of their ship that really wasn’t a ship at all.

“It works! And it’s going to help a lot, that aerial is,” Sally exclaimed a few minutes later.

This was true. They were able now to catch the “put-put-put-put” of those secret broadcasts sent from radios out somewhere on land or sea very plainly. That night they stayed up till midnight, and were able to locate seven different broadcasters.

“They are all part of something big, I know that,” Sally insisted. “But is it a sub pack, a flight of planes, or a convoy of ships?”

“Only time will tell,” was Nancy’s reply.

Just then they caught the sound of voices in the hall and suddenly their secret listenings to the great unknown were at an end. For if the secret radio were to remain just that, they must take great care not to expose either the black box or the purpose of their own midnight meetings. The two conspirators did not intend to be found out.

There was a glorious hour at sunset in every day of work when Sally was free to do as she chose. What she chose more often than not, in the days that followed, was to visit a certain radio lab in one of the school’s regular buildings. Here she found Danny waiting to help her with her problems. She discovered at once that he did know a very great deal about communication and about radio in particular.

When she complimented him on his knowledge he threw back his head and laughed.

“It’s no fault of mine,” he exclaimed. “I’ve had it drilled into me from the very start. We’re in the Navy. Don’t forget that. Most of us will be on aircraft carriers. That means we’ll be out over the sea in small planes.”

“Alone?” Sally asked.

“Sometimes, sometimes not. You may have a radioman and may not. Anyway, he may get killed. So you have to know all about radio, blinking lights, waving flags, and a lot more.

“Say!” he laughed. “I could propose to a good signal girl in ten different ways.”

“Wait till I get up on all the codes,” Sally laughed.

“Oh, yes. Well, then, let’s get busy.”

He picked up a booklet entitled, “International Code” and; turning to page twelve, said:

“Morse code isn’t half bad. See! Here it is.” Sally looked over his shoulder. “A is dot, dash; B is dash, dot, dot dot, and so on down the line. You can learn all that in about no time. But receiving takes longer. Those birds send out messages like greased lightning. You’ve got to think fast and be accurate at the same time. That’s tough. But it’s absolutely necessary, especially in your work. To read a message wrong, skip a dot here and miss a dash there, may sink a ship, or even a half dozen ships.”

“Oh!” Sally held her head. “That sounds serious!”

“It is. But see here, why do we waste a beautiful sunset hour on code? You’ll get that in your next school anyway.”

“Yes, I know, but I want it now. It,” she hesitated, “it’s not my secret alone so I can’t tell you too much.”

“You don’t have to tell me anything,” he replied with a generous smile.

“But I want to. That night when I fell off the roof I was running a wire from my room to the aerial on the roof. I’ve been working for a long time with a dear old man who’s a real genius. He invented a special kind of radio and he gave me two of them to try out.”

“I see. That’s what you’re doing now. Did the outside aerial help?”

“Oh, yes, a whole lot. The ‘put-puts’ come in a whole lot more distinctly.”

“The what?” He stared.

“The ‘put-puts’. That’s what we call them. I suppose it’s some special form of code, but it’s not like any I’ve ever heard on the short wave section of our radio.”

“I wish you’d tried to write it down,” he said thoughtfully. “Perhaps they have a secret code. They may substitute numbers for letters. See, here are the numbers in Morse Code. Dot, dash, dash, dot are for one, for two you add two dots and drop a dash-dot, dot, dash, dot. Three is dot, dot; dot, dash, dot, and so on.”

“That doesn’t sound too hard,” interrupted Sally.

“It’s simple. Take this book home and learn the numbers. Then listen to your radio and try to write down the ‘put-puts’ in dots and dashes.”

“I will if they are there tonight. Sometimes they’re not there at all and sometimes there are a lot of them, five, six, or a dozen, all talking to one another like frogs in a pond.”

“Is that right!” He suddenly became excited. “Say, perhaps they are in a pond, the big pond. Perhaps they are wolves instead of frogs.”

“Wolves?”

“Sure, enemy subs, wolf-packs of them, you know. Wouldn’t that be a break?”

“I—yes, I suppose so.”

“You suppose so! Say! You don’t know the half of it! These wolf-packs are known to have some means of talking to one another under the water.”

“They’d almost have to.”

“Sure they would, but all the bright minds in Europe and America can’t find out how they do it.

“But then,” his voice dropped, “probably your ‘put-puts’ come from a flight of planes crossing to North Africa.”

“Or from a convoy.”

“Sure. We, too, have our secret methods of communication, but if your old friend has invented a new one, they’ll make him an admiral.”

“It’s up to me to prove it. That’s why I’m so anxious about it.”

“It is? Well, then, we’ll really dig in. Try out my code idea. Then we’ll meet again at sunset tomorrow.”

“It’s a date.” She left the lab with a smile. Even if nothing came of this code idea she had made a grand friend and that was always worth while.

Late that evening while others wrote letters, read or slept, Sally gave herself over once more to solving the riddle of the secret radio and its “put-puts.” She had made very little progress when the signal sounded for lights out.

“Oh, dear!” she sighed. “No day is ever long enough.”

She had been in bed for a half hour but had not fallen asleep when suddenly she caught a gleam of light from Barbara’s bed.

“Barbara!” she exclaimed. “What are you doing?”

The light blinked out and Barbara’s head came out from beneath the covers.

“I’m sorry!” Barbara whispered back. “These studies are so hard and there are so many of them I never get caught up. So I’ve been studying with a flashlight under the covers. No one would know it but you.”

“Such determination!” Sally exclaimed in a low voice. “You should have a medal or something. But you’ll smother!”

“Oh, no!” Barbara laughed. “I’m like a seal. I come up for air.”

“Anyway it’s an idea,” said Sally. Hopping out of bed, she gathered in her precious radio and, with a bed cover for a tent, studied the “put-puts” for another hour.

The close of that hour found her thoroughly disgusted. On a paper she had made a few marks. When she had compared these to the code marks for letters and figures, they added up to exactly nothing.

“Terrible,” she thought. “I know what I’ll do. I’ll take the radio over to the lab and show it to Danny. I’m sure he can be trusted. We’ll work things out together.”

“What’s that black box?” Danny asked, when she arrived next evening.

“That’s my secret radio. I couldn’t do a thing last night. I want you to help me.”

“It’s nice of you to trust me.” He beamed. “People have said I was simple but could be trusted. Only time will tell.”

“Time doesn’t need to tell me. I know it.”

“Do you? Well, then that’s fine. How do you open this black box?”

She snapped it open. “Oh! We need an aerial!”

“There’s one on this building, much better than the one you’ve been using. There’s a connection over in the corner.”

In a few minutes the radio was ready to operate. Sally turned the switches. Nothing came out, not a sound.

“What’s up?” Danny asked.

“Those gremlins, subs, or whatever they are, are not always there.”

“Turn the dial. Get something else. That will tell us whether our connections are okay.”

“There’s nothing else on the air for us.”

“That’s a queer radio.”

“Yes, it is. But if we wait five minutes Station NANCY will be on the air.”

“And in the meantime?”

“Tell me about parachutes,” she begged. “You’ve dropped a time or two, haven’t you?”

“Naturally. I’m a flier.”

“How does it feel to drop for the first time?”

“Just fine if you think of something else most, of the time. It helps to sing:

“But why all the interest in parachutes?”

“My roommate is going to be a parachute rigger.”

“I hope she’s a careful sort of lady. I saw a boy drop two thousand feet straight down. His rigger had failed him.”

“I’ll rig my own.” Sally’s lips were a straight line.

“Why should you go in for parachutes? But then—oh, yes—you go in for all sorts of falling.” He laughed.

“No,” she said, “I don’t. I get dizzy. But I promised Barbara that I’d go down with her it they asked her to try parachuting.”

“You did! That takes courage!”

“Where’s the war job that doesn’t?”

“Oh, it’s not so bad.” He blew an imaginary smoke ring. “You just sit on the edge of a hole until they give you the word. Then you look up, slide through the hole, and down you go. When the parachute is open it is really swell, like dreams we have of flying just with our hands. When you land you curl up like a sleepy kitten, roll on the ground, then get up.”

“You make it sound so nice!”

“Why not?”

Sally turned a knob on the radio. She snapped on a headset and said: “Hello, are you there?” Then she listened.

“How do you get me?” she spoke into the mouthpiece again. “Good as ever? That’s fine. This is Sally signing off.

“See!” She turned to Danny.

“Pete’s sake! What wave-length do you use?”

“I don’t know.”

“What?”

“Only one person in the world knows that. He’s the man who made it. My old friend C. K. All I know is, it’s very short. Watch!”

She snapped off the lights, then pulled down the shades. The radio’s tubes glowed red.

“Say! A radio with its own private wave length is worth a fortune! I know a man high up in Communications. Let me show it to him.”

“Not for worlds.”

“You’ll be rich and famous.”

“No! No! Oh, I wish I hadn’t brought it here. Can’t you see that it was loaned to me by a very dear friend and that he alone can release it?”

“Yes,” he replied soberly. “I won’t breathe a word about it until you give me the sign.”

“Thanks—oh, thanks!” she stammered. “You really had me worried.”

“And now,” he said, “how about having another try at the ‘put-put’ of the gremlins, or subs?”

For ten minutes more they sat there in the dark watching the red glow of the strange radio tubes but hearing just nothing at all.

Then, suddenly, it came, a low “put-put-put-put-a-put-put-put-put-a-put.”

For a long time Danny sat there silently listening. “It’s code, all right,” he murmured once. “There’s a sort of rhythm to it, just as there is to all code.”

“If you turn this dial,” Sally whispered, “it will throw them out.” She turned the dial. Silence followed, but not for long. Again came “put-put-put-a-put.”

“They’re back,” he whispered.

“No, that’s another one. Listen! You can tell the difference.” She brought the first one back, then switched to the second.

“What do you know about that!” He was all ears.

“Perhaps the ‘put’ stands for dot, and ‘put-a-put’ for dash,” he suggested. “I’ll just try it that way.”

“Might be the opposite!”

“Sure, just anything.” He snapped on a small light and then began marking down dots and dashes as he listened. For a long time neither of them spoke.

“That might be it,” he breathed at last. “It’s hard to take down, but I’ve got dot, dot, dot, dash, dot. That’s three, dash, dash, dash for five and dash, dash, dot, dot, for seven. Then there are some numbers that seem like seventeen, twenty-three, and thirty-one. I can’t be sure—”

“Give me a pencil and paper,” she suggested. “Let me play the game.”

For a long time after that they listened and marked down dots and dashes. When one sender went off the air they switched to another. In time they came to believe that number one and number two were holding a conversation. Then number two went off the air, followed by number one.

A little search found a third. When number three went dead, number one was at it again. It became an interesting game of hide-and-go-seek, in the air.

“Could it be one of our convoys?” Sally asked.

“Hardly that. They maintain radio silence, I’m told. But with such a radio, who knows? But if they are subs, a whole wolf-pack of them!” he exclaimed a moment later.

“And if we could spot them!”

“While we were on a ship, an aircraft carrier! Spot them some distance away and go after them with a dozen planes loaded with depth-bombs. I’ll tell you what!” he exclaimed, becoming greatly excited. “I’ll be ready to sail in a month or two, on an aircraft carrier. You get a radio job on my ship. Then we’ll really try this radio out.”

“They’re not sending WAVES on ships yet,” she reminded.

“Oh! We’ll manage it,” he insisted, “We’ll just have to.”

“We may discover that we’re mostly just duplicating one of Uncle Sam’s secrets.” Sally was cautious by nature. “These code signals may come from American ships or airplanes.”

“Tell you what!” he exclaimed. “We’ve just got to de-code their messages so we can tell what they say. Then we’ll know. But that,” he sighed heavily, “looks like a long, long job.”

They pitched into that job once more and had been working for some time when he said: “By the way, did you have a class tonight?”

“Yes, from eight to nine.”

“Never mind then, it’s nine now.”

“Oh!” she exclaimed. “I must go! I’ll get a black mark. Unhook my radio and let me go.”

“There you are,” he said a moment later, as he handed her the radio, “but you’ll be back?”

“Oh! Sure! It’s been exciting. Just think what it will mean if we really do something big with old C. K.’s radio.”

“I have been thinking,” he replied soberly. “Just keep trying, and mum’s the word. We’ll get there yet!”

During the week-days that followed, there were no more long night trysts over the secret radio. Sally had a record to maintain. She had resolved at the very beginning to be one of the best WAVES ever entrusted with a job in Communications. She had decided, too, to move heaven and earth to get a spot on some ship sailing the seven seas. She knew quite well that the best way to get what you want is to earn it. Classes must always come first.

For all that, she and Danny did each day spend one glorious twilight hour working away at the secret radio. When Saturday night came, the WAVES one free night, Nancy joined them, and working both radios at once, they really went places and did things. Using both radios, they spotted as many as eight broadcasters of the mysterious pack on a single night.

“Are they really enemy subs?” Nancy asked.

“Who knows?” was all Danny would say. “If they are we’ve really got something.”

“But they may be cargo ships in a convoy or airplanes going to Europe,” said Nancy. “Then why don’t we ask our Communications people in Washington whether they are using that wave-length.”

“Two good reasons,” Danny grinned. “We don’t know the wave-length we’re using and if we did the folks in Washington wouldn’t tell us.”

“Probably send an F. B. I. agent to look us up,” Sally said. “No, dearie! We’ve got to work it out all by ourselves.”

“Just give us time and we’ll make it,” Danny declared. Ah, yes, there was the rub. All too soon the bugle would blow and they would be scattered far and wide to new fields of endeavor.

They made some progress. One evening Danny exclaimed: “See here! The numbers they are sending—if they are numbers—are all odd. Seven, seventeen, thirty-one, forty-three. There’s not an even number in the lot.”

“That narrows it down,” said Sally.

“It sure does.”

Two evenings later Sally made a more important discovery.

“Look!” She jumped to her feet in her excitement, to point at a row of numbers. “Not one of them is evenly divisible. Seven, seventeen, thirty-seven, fifty-three, every last one of them. Does that mean anything?”

“It may mean a lot,” was Danny’s excited comment.

“Oh, there’s the bell!” she exclaimed. “Time for class. Think of dropping this discovery just like that.”

“It’s not dropped.”

Danny dragged out a tall stack of papers. “I’ll still be working on that when you’re fast asleep.”

“Danny, you’re a treasure!” she exclaimed, giving his hand a quick squeeze.

“It’s all part of the game,” he grinned. “We’ll be famous, both of us, and your old friend C. K., as well.”

The hour was striking midnight when at last Danny stacked the papers in a neat pile.

“Got it!” he breathed. “It’s the berries. Can’t be any mistake about that. We’re really making progress. But we’ve still got a long way to go.”

That very night one more major problem brought Sally’s radio experimentation to an abrupt halt.

She returned to her room, after her late hour of study, to find Barbara sitting in her bed staring gloomily at the floor.

“What’s the matter?” she asked. “Been caught out of bounds, or something?”

“I haven’t done a thing,” Barbara replied gloomily. “Perhaps it would be better if I did. When you never step off the beaten path, just plug along day by day, people ask you to do such terrible things.”

“Why? What have they asked you to do now?”

“It’s that parachute drop.” Barbara stared gloomily at her feet. “They say it’s not really required that a parachute rigger should take parachute training, but that if they do take it, and if they do take just one drop, they make better riggers.”

“Of course they do,” Sally agreed. “They know what it’s all about.”

“That sounds all right. But would you want to go to an airfield where only men are training, and go through all the practice and finally take the drop, all by yourself?”

“No, of course not. Are they asking you to do that?”

“Not asking, just suggesting.”

“Which in this war is the same thing. Tell you what—” Sally came to a sudden decision. “If Lieutenant Mayfare will let me, I’ll go through the training with you.”

“You wouldn’t!” Barbara stared.

“I said I would, didn’t I?”

“Yes, but you don’t have to.”

“No, of course not, but I want to. If I’m to go in for Radio and Communications I want to be prepared to serve anywhere, on land, on the sea, or in the air.”

“You’re the daffiest person I ever knew—and the dandiest!” At that big Barbara hugged Sally until she thought her ribs would crack.

“But, Sally, you don’t have to go in for parachute jumping if you’re going in for Radio,” Lieutenant Mayfare protested when Sally made her unusual request next day.

“But I want to,” Sally insisted.

“You’re doing it to help Barbara. Is that fair to yourself?”

“Who knows what is fair?” Sally asked quietly. “It’s not fair to ask a boy to give up his college work right in the middle of his first year to go to war. Or is it? It’s not fair to ask a father to leave two small children for the same reason. Or is it? Who knows—

“Anyway I’d like the experience,” she added after a brief silence. “There are several things we are not being asked to do now. Perhaps tomorrow or next month we will be asked. I want to be prepared. And after all, I think it’s a small matter.”

“Not so small.” The officer spoke slowly. “You’ll have to spend the last half of every afternoon for a week preparing for it.

“Of course,” she added, “your work here has been excellent. The time lost will not matter so much. So—”

“Then I may do it?” Sally exclaimed eagerly.

“Yes, you may!”

“Oh! Thank you! Thank you a lot!”

“It is Barbara who should be thankful. I doubt if she could take the test alone.”

“She couldn’t,” Sally agreed. “Barbara is a fine girl. She’s true blue. There are not many things she could do in our organization. For parachute rigging she’s perfect.”

“That’s right.”

“And I want her to be a great success.”

“With your help I’m sure she will be. You and she may start your training this afternoon. The sooner the better. There’s not much time left—”

And that is why Danny Duke had to wait so long to tell Sally of his grand discoveries.

That afternoon Sally and Barbara rode five miles to the training field with six boys who were to take the same training.

“Pipe the girls,” one fellow called when they were first sighted.

“Shut up!” another boy exclaimed low. “If they are going to take to the chutes, it’s not just for fun. It really takes guts. If they’ve got what it takes you have to hand it to them.”

“Ever run a children’s playground?” the director asked Sally.

“Yes, once, quite a while ago—”

“Well, this is just another one of them. Only difference is you swing on your chute straps just to get used to them instead of from the old apple tree. And if you don’t fasten your straps just right you get a good bump.”

“And you learn by bumps,” Sally laughed.

“Yes, and that way you don’t get killed later.”

“It’s the same way with the slide,” the instructor added. “It’s just a kid’s slide, only longer, and you fall harder—that is, if you don’t relax properly.”

After that, for a full week-the two girls practiced swinging, sliding, tumbling, whirling round and round.

“I feel as if I’d been put in a cement mixer and whirled round and round a thousand times,” Sally confided to Danny on Saturday afternoon. “But I do believe that Barbara will go through with it. Monday is our zero hour. We drop at dusk. And I’m keeping my fingers crossed.”

“I’ll say a prayer for you,” Danny grinned. “And now about this secret code of the gremlins, the enemy subs, or what have you.”

“Yes—yes!” Sally exclaimed eagerly. “What did you find out?”

“A whole lot and yet, not half enough. Come over just after chow, if you can. Bring the radios and I’ll tell you all.”

“Oh, no! Surely not that much!” Sally held up her hands in mock horror. “All the same, I’ll be there!”

“It’s like this,” Danny said, as they sat before the radio that night listening to the “put-put-put-a-put.” “They’ve made their code from numbers that can be divided evenly. I’m sure of that. But does one stand for the letter A, or have they arranged it all backwards?”

“They may have started in the middle and gone both ways.”

“Yes, but I don’t think they did. Why should they? They had the wave-length all to themselves. Why not have a simple code? I even think they let one stand for A, three for B, five for C, and so on.”

“What makes you think that?”

“Because eleven, which should stand for E, is used more times than any other number and E is the most-used letter in the alphabet. Other vowels stand out in the same proportion. So I think we’ve got that far. But now,” he sighed, “we’ve got to find out whether they’re sending in German or English. That is going to be hard.”

“And must be continued in our next.” There was a suggestion of gloom in Sally’s voice. She was tired and sore. Much lay ahead.

“Monday we drop from that hole in the sky. Tuesday we take our finals,” she sighed.

“And Wednesday you scatter,” he supplied. “I got that on good authority. Some of you go to other schools and some to work, depending on what you’re taking up.”

“That’s about it. We’ll just have to work and hope we meet again over this blessed, tantalizing, mesmerizing radio,” she laughed. “And now, what do you say we take the radio over to my house and then make a night of it?”

And that was just what they did.

Monday afternoon came, and with it, many a long-drawn breath.

“Sally, I’m scared,” Barbara whispered, as they piled into the car that was to take them on their last trip to the field.

“You wouldn’t be natural if you weren’t,” was the cheering response. “All the same, try to forget it.”

In the week that had passed, the eight of them, two girls and six boys, had formed the habit of singing on the way out. Now, when at last they rolled away, a youthful voice struck up: