Dorothy donned her overalls while Bill spoke to the mechanic who was waiting by the plane. Then the man got into a car and drove away, and Bill beckoned her to him.

"All set?"

"All set."

"Then we'll begin. First of all, you must know the names of the different parts of the plane. Some you know already, but we'll go over them just the same. That hinged movable auxiliary surface on the trailing edge of the wing is an aileron. Its primary function is to impress a rolling movement on the airplane. Got that?"

"Yes."

"Then repeat what I just said."

Dorothy did so.

"Good. Now this is a drag wire."

After twenty minutes of this kind of thing he asked her to point out an aileron and explain its use.

"K.O." he said at last. "We'll go over parts each day for a while and the book work you must do at home will help to refresh your memory. Now nip into the forward cockpit and I'll explain the working of the controls."

He gave Dorothy a hand up and when she was seated, swung himself on to the cowl of the cockpit.

"First of all--and let this become habit--" he ordered, "adjust your safety belt. Yes, that's the way. Now we'll go ahead. That's the stick there. Take hold of it. You'll notice it is pivoted at its base. Forward movement of the stick increases the angle of attack of the elevators and depresses the nose. Backward movement decreases angle and raises the nose. Lateral movement of the stick operates the ailerons, movement to the right depressing the right wing, and to the left, the left wing."

When she was sure she understood the functions of one thing he explained the next.

"Now tell me just what I have told you--" he commanded.

Fully an hour had gone by before he was satisfied that she understood thoroughly.

"Tired?" he asked at last.

"Not a bit," she smiled. "I'm afraid I'm kind of dumb--but all these gadgets, as you call them, are a little confusing at first."

"Oh, you're catching on in first rate order," he told her. "Nothing but practice will make you letter perfect. And that comes soon enough when you handle the plane yourself. Now I'll fly us home. All I want you to do is to fold your arms and listen. Keep your eyes in the cockpit and watch the movements of the stick and rudder bar. My cockpit aft is equipped with similar controls. When I move my stick--yours moves--and vice versa. All right?"

"You bet."

He reached in his pocket and drew forth a small leather-bound book which he handed her.

"Here's your Flight Log Book, Dorothy. Write it up after every flight. There are columns for the date, type of plane, duration and character of flight, passengers or crew carried (if any) and remarks. A commercial pilot should have his log book certified monthly by an official of the company. For a student it is a good thing to commence during training. Stick it in your pocket," he advised as she thanked him. "And put on this helmet. It's a Gosport, with phones in both ear flaps, connected by a voice tube to this mouthpiece. I'll use that end of it to coach you through during flight."

"But this helmet is hard and stiff," objected Dorothy. "I'll bet it isn't nearly as comfortable as that nice soft leather one you're wearing."

"Possibly not. But until you're through with your instruction I want you to wear a 'crash' helmet. They're a lot of protection for the head in case of minor accident. No instructor worth his salt permits a student to use a soft leather helmet until you've had a lot of experience."

"Oh, very well then," she said, adjusting her heavy headgear, "you're the boss!"

"You bet I am when it comes to this kind of thing. If I weren't sure you were willing to give me strict obedience, I'd never propose teaching you. And please remember that this isn't a joy hop. The more attentive you are to instruction--the quicker you'll learn."

"I'm your willing slave, sir," she mocked good-humoredly, and drew the helmet strap tight beneath her chin.

Then as the engine roared and the plane rolled forward she felt the same thrill she had experienced the afternoon before when she and Bill had taken off in the amphibian. The same tightening of her muscles and beating throb of the pulse in her neck. They were soaring upward now and the sensation of smoothness became apparent after the jars and bumps of taxiing over the rough field. The sting of the wind on her face was exhilarating, but her eyes were streaming. Realizing that she had forgot to adjust her goggles, she pulled them down from the front of her helmet.

"I've been wondering how long it would be before you did that," came Bill's voice through the headphones. "Never mind--it's a grand thrill while it lasts--you'll lose it soon enough."

Dorothy, for the first time in her life, found a retort impossible to make.

"Now that we've got enough air under us," Bill's voice continued, "I'm going to fly straight for home. Remember what I said about watching your stick and rudder bar. Also keep an eye on the bank-and-turn indicator as well as the fore and aft level indicator and inclinometer."

Dorothy shifted her gaze to the instrument board before her. Unconsciously she ticked off the other instruments. There were the two Bill had just mentioned; a magneto switch, oil pressure gauge, earth inductor, compass indicator, altimeter, 8-day clock, primary pump and tachometer. It pleased her that she could so readily recall their names and uses. Then she heard Bill's voice in her ear again:

"The reason that I keep pulling the stick back slightly so often, Dorothy, in level flight, is because the old bus is a bit nose heavy. You'll notice it when you handle her later on. It's nothing to worry about. Very few planes are perfectly balanced."

Dorothy turned her eyes guiltily on the stick again. She had been caught napping that time! One really needed half a dozen pairs of eyes for a job like this. And--how different Bill's manner aboard an airplane, she thought. He was certainly all business. But she respected and admired his knowledge and his ability as an airpilot which left no opening for argument.

"You can look overside now," came his voice again interrupting her thoughts. "We're going to land."

Below them she saw the Bolton's house. The nose of the plane dropped suddenly as the stick went forward and they shot down to land on the field near the Bolton's hangar.

Bill spoke again from the rear cockpit. "If you're ready for more flight instruction, hold up your right hand."

Dorothy held up her right hand.

"Good. Then we'll practice taxiing," came back the even voice. "Remember that a land plane with engine idling will remain at rest on the ground in winds of normal force. That means that all movement of the plane must be made by use of the engine. When your bus begins to move you control it primarily by using the rudder. In a wind as strong as the one blowing now, you'll notice the plane's tendency to turn into it. That's due to the effect on the tail. It tends to swing like a weathervane until the nose is headed directly toward the point of the compass from which the wind is blowing. Your experience in sailing is going to be a great help.

"Now, just one thing more and we'll shove off. While taxiing, you must hold the stick well back of neutral. That will prevent any tendency of the tail to rise and cause the plane to nose over. Grasp the stick lightly with your fingers. Never freeze onto anything. If you feel me wiggle the stick sharply--let go at once. I may or may not have my hands and feet on the controls, but you cannot know that. Act just as if you were alone in the plane. Got all that?"

Dorothy raised her hand again.

"Then snap on the ignition and get going."

For the next hour she taxied the N-9 around the field while Bill issued commands from the rear cockpit. So interested was she in her lesson that it seemed no time at all before he told her to shut off the engine.

"Take off your helmet and get down," he said as the plane came to a stop. And he helped her overside.

"Gee, Bill, it's wonderful!" she cried, jumping lightly to the ground beside him.

"You did splendidly," he encouraged. "This field is pretty rough in spots--makes it bumpy going. How are you--stiff?"

"Not a bit!"

"You need a rest, just the same."

"But I'm not in the least tired. Can't I go up now?"

Bill looked at her and shook his head. "Nothing doing," he said with pretended sternness. "That is--not for the next fifteen minutes. Here comes Frank with something cold to drink on his tray--horse's neck, probably. There's nothing like iced ginger ale with a string of lemon peel in it when you're real thirsty!"

"My, you're thoughtful!"

"Don't thank me--it's all Frank's idea."

They sipped their drinks in the shade of the old barn that had been turned into a hangar for the Bolton's planes.

"While you're resting, I want you to study this paper, Dorothy. It's a routine I want you to follow in preparing for every flight you take--with me, or soloing," he explained, handing it over. "When you've got it by heart, repeat it to me and then we'll carry on. Your first job for the next hop will be to do exactly what I've written there."

For perhaps ten minutes both were silent and Bill closed his eyes and turned over on his back.

"Asleep?" asked Dorothy presently.

"No--just relaxing. Got that dope down pat?"

"Sure. I mean, yes, instructor."

"Give me back the paper then, and shoot!" he said, sitting up.

"Preparations for flight:" recited Dorothy. "First, inspect the plane and engine as necessary. Second, observe the wind direction. Third, observe the course direction (if a course is being flown). Fourth, set the altimeter. Fifth, see that helmet, goggles and cushions are properly adjusted. Sixth, see that cloth to wipe goggles is handy. Seventh, give the engine a ground test. Eighth, see that the gas valve is properly set. Ninth and last--Buckle the safety belt!"

"One hundred per cent! Good work, Dot. Now come over to the plane and show me how you do it."

He grinned, awaiting a quick retort--but Dorothy, intent on the business of learning to fly, walked at his side in a fit of concentration.

"She sure is keen," he said to himself. "I never got a rise--and 'Dot,' to Dorothy, is like waving the American flag at a Mexican bull!"

Dorothy continued to prove her aptitude for she went through the flight preparations with but one mistake. She entirely forgot the matter of the cloth to wipe her goggles!

Presently he took her up again and started in with his coaching.

"You now have thirty-five hundred feet registered on your altimeter," he announced through her phone. "Enough air below to get us out of trouble if we should happen to get into it. The higher one flies, the safer one is. Now you are going to get straight flight instruction. I am moving the stick backward--now forward--now backward--now forward. See how the nose of the plane rises and falls in response? Watch closely--I'm going to do it again. There, now--take the stick and do it yourself."

Dorothy did as he bade her. It was thrilling to feel the huge plane respond to her will.

Then followed instruction in moving the stick successively right and left by which means the right wing and then the left are correspondingly depressed. After that came rudder instruction. First Bill pushed the right and left sides of the rudder bar successively, forward, thereby swerving the nose first to the right and then to the left.

Dorothy, of course repeated these movements after him.

Then he explained that to hold a steady course, to fly straight, constant right rudder must be maintained to overcome the torque, or drag of the propeller blades tending to swing the nose to the left. While to fly level longitudinally, some point on the engine is kept in line with the horizon. That to fly level laterally, up aileron and opposite rudder are applied whenever a wing drops. He told her numerous other things, such as that when flying straight, the nose should frequently be dropped momentarily, or the course changed a few degrees in order to look ahead. Otherwise, an approaching plane may be hidden by the engine.

"Good night!" thought Dorothy as she strained her ears to catch every word, while she watched the controls and saw how the plane reacted to their manipulation by her instructor. "If it takes all this detail to fly straight and level, I'll get the heebie-jeebies when it comes to acrobatics!"

"Take over controls," came Bill's voice. "Fly straight for that white church tower on the horizon."

Dorothy's body stiffened, but she took hold of the stick again bravely enough, and placed her feet on the rudder bar at the same time. She could feel her temples throbbing, and her heart was beating faster than the clock on her instrument board. At last she was actually flying an airplane--all by herself. But was she? Suddenly there came a check in the forward speed of the plane and Dorothy felt it start to slew off sideways as the nose dropped.

Then before she knew exactly what was happening, the stick in her hand seemed to spring back, then to the right, while right rudder increased considerably without help from her foot. Up came the nose, followed by the left wing, and down went the right. The slewing stopped as suddenly as it had begun. Then she felt left aileron and left rudder being applied--and once more the N-9 was flying straight and level.

"Forgot what I said about checking a skid just now, didn't you?" said Bill's voice in her ear. "Here's the news again. Any swinging of the nose to the left can be promptly recognized and checked--but,--and here's where you went wrong--the nose cannot be swung back to the right without applying a small bank. Any attempt to do so will cause your plane to skid. That naturally results in a loss of flying speed forward and the heavier end drops. If not checked at once, it means going into a spin. Carry on again now, and please try to keep your wits about you. This is not a kiddie-car. Mistakes are apt to be costly!"

Dorothy bit her lips in anger. More than ever did she regret the lack of a mouth piece on her head phone. Her temper flared at his sharp tone, and what seemed to her unfair criticism so early in the game. But she took over again as he ordered and gradually her vexation disappeared in her effort to concentrate every faculty on the job of flying the plane and keeping to her course. She was gradually gaining confidence. She made the same maneuvers which had caused the skid before, and carried through perfectly.

Bill told her so in no stinted terms, and the last shreds of her anger disappeared.

"The man who put me over the bumps," he added, "always said: 'when a student aviator makes a mistake, give him blazes--make him mad. He'll remember what he should have done all the better--and live longer!' That advice applies to either sex, Dorothy. Naturally, I hope you'll live to a ripe old age."

Dorothy liked him for this apology. She wanted to thank him but of course that was out of the question.

"I'll take her over now." She heard his even tones once more, above the engine's roar. "Time for lunch. This afternoon, if you like, we'll take up another end of this business. And you can get even by teaching me how to become an honest-to-goodness sleuthhound!"