Five members of the “D” club had gathered in Jack Straw’s room on the top floor of Phillip’s Hall the last Saturday afternoon before the end of the Spring term. They had not assembled in official conclave, indeed they had not intended to assemble at all. They had merely gravitated there one by one in search of something to take their minds off the worst disappointment they had been compelled to face that year. The Drueryville-Seaton baseball game, the one that was to have settled the preparatory school championship of Vermont, had been scheduled for that Saturday afternoon, and, lo and behold, in spite of the importance of the day, Jupiter Pluvius or whoever it was that controlled the rain supply,[2] had made the game impossible by deluging everything in sight since early morning. And there was no chance of postponing the contest either as school closed the following Friday. The championship would have to remain undecided. And this was just the year Drueryville stood a better chance than ever of adding the “prep” cup to her trophy case. It was enough to make anyone glum. “They should have named this place Drearyville instead of Drueryville,” muttered Toad Fletcher, the stocky little catcher of the team, as he looked across the deserted campus at the dripping eves of Bradley Hall.
John Monroe Strawbridge, who was known to every boy in school as Jack Straw, shifted his position on the window seat so that he could take another look at the weather.
“It is pretty gloomy on a day like this,” he answered after searching the leaden sky for some signs of a break in the low hanging storm clouds.
Jack and Toad were too dejected in spirit for conversation and since Bunny Baily was deeply engrossed in a book of fiction and Dick Cory[3] and Harvey Maston were working out an absorbing game of checkers silence reigned in the room for some time. In fact a stranger passing the door would never have suspected that five perfectly normal, healthy boys were within. But then the “D” club was composed of the honor boys of Drueryville Academy and for that reason if no other, they were bound to be more dignified at times. You see the “D” club was made up of the students who had won the privilege of wearing a white and blue initial, the insignia of the school, on their caps or jersey; and in order to earn that distinction a boy must needs work hard both in the class room and on the athletic field. When a youth successfully attained such laurels the crown was apt to weigh heavily.
How long the clicking of checkers would have remained the only sound is hard to tell had not Tommy Todd happened to see Jack Straw curled up in the window seat. He paused a moment before Phillip’s Hall and waved his hand in friendly greeting. Then he splashed across the muddy road and came up the stairs three steps at a time. Like a small[4] portion of the storm itself (for Tommy was by no means a big boy) he burst into the room, his yellow raincoat and rubber hat dripping wet.
“Say, don’t flood the place!” shouted Jack as he noted two growing pools of water on the rug.
But Tommy only grinned as he removed his wet garments and draped them over the back of a chair so that they would drip on the hearthstone.
“Sort of hard luck to have a day like this happen along just when it isn’t wanted,” he suggested to no one in particular. Then without waiting for a response he looked at Jack and spoke.
“Say old man, I can’t think what on earth you’ve been up to recently, but there’s something in the wind. Dr. Moorland wants to see you as soon as possible. I just came from his house and he asked me to look you up. I was going on downtown first because the last place on earth I ever expected to find you was in your own room. What’s the trouble anyway? You haven’t done something that will keep[5] you from getting through next week, have you? It’s mighty close to the end of the term and I hope you’ve been careful.”
At this Cory and Maston suspended their game for a moment and Bunny Baily put down his book. All eyes were turned on Jack Straw. And as for Jack, it must be confessed he looked startled and somewhat worried. Hastily he ran through his mental diary, but so far as he could see no one entry stood out above the rest as warranting reprimand from the principal.
“I haven’t the slightest idea what he can want of me,” he assured his guests as he hastened into his bedroom and donned raincoat and rubbers. A few moments later he hurried out into the hall and down the broad stairs toward the main entrance. As he passed the mail rack in the hall he noticed a letter waiting for him. Hastily he seized it and crammed it into his pocket, noting as he did so that the address was written in his father’s hand.
Dr. Theodore Moorland, the principal, lived in a modest little cottage on the north side of the campus. It was almost hidden in a grove[6] of tall maples and, as if to make itself more inconspicuous, it had permitted woodbine and ivy to clothe its gray stone walls in a cloak of soft green. A graveled road that wound between fat old maples showed the way to the front door, and it was up this much used path that Jack Strawbridge hastened, his mind still puzzled over the reason for such an unusual command. The heavy old-fashioned door to the cottage was equipped with a ponderous brass knocker of quaint design which thumped with such resonance as to spread consternation in the soul of youngsters summoned thither. Thus they were thoroughly disturbed before they even faced the austere old master.
Such was not the attitude of Jack Straw, however. He had not been able to remember a single reason why he should expect to face a scolding from Dr. Moorland. Every examination paper had come back with excellent markings and his conduct for some time past had been beyond reproach. He thumped the old door knocker twice in his eagerness to find out just what the master wanted. Perhaps it was news from home, he thought, and he comforted[7] himself by the fact that nothing serious had happened to his father, for the letter in his coat pocket attested to the fact that he was still well enough to write. But while he was speculating thus the door was opened by Dr. Moorland himself.
The dignified pedagogue greeted the boy with a broad smile and a hearty hand shake.
“I didn’t know but what you and some of the rest of the boys had about grieved yourselves to death over your ill luck at having the championship game broken up by the weather,” he said as he ushered Jack into his study in a secluded wing of the house.
“It is rather hard on us,” said Jack with a smile. “Here we’ve been working since February to get our team in shape for the trophy contest and then a little thing like the weather spoils it. Next year I think we will have to arrange to have the championship game a little earlier so there will be enough time to play it in case of an emergency like this one.”
“Never mind, Jack, my boy,” said the principal, “I have a mission for you that is calculated[8] to take your mind off baseball and similar troubles for some time to come.”
The boy was plainly puzzled at this remark. He looked curiously at the principal who was striding the room nervously. Dr. Moorland was a tall, broad shouldered man of sixty. His hair was snow white and so long in back that it curled down over his coat collar. A pair of horn rimmed spectacles that were constantly sliding forward on his nose made him appear to be a testy individual, but in reality he was a genial old gentleman who loved his boys as much as if he was the father of every one of them. The State of Vermont counted him among the best of its educators and he was famed throughout the country, indeed throughout the world as a chemist.
“Jack,” he said after a long silence, “how would you like to go to Mexico?”
“To Mexico!” gasped Jack.
“Yes, to Mexico. It will be an opportunity for you to see a wonderful country and also to make enough money to pay your tuition at Drueryville next year. Do you care to go?”
“Why—why—Oh, I’d be delighted—but—well[9] I’d have to get father’s consent first, you know.”
“Ah, Jack, you don’t suppose I would have suggested the subject before consulting your father about it, do you? I wrote him several days ago and asked his permission to let you go. I received word this morning that he was perfectly willing to have you avail yourself of the chance to see a little of the world providing you cared to go. I wonder that he hasn’t written to you about it.”
“Why, perhaps the letter I have in my pocket now is about that very thing,” said Jack, searching in his pocket for the envelope.
“Very likely,” said the principal, “but you can read it after. Let me explain exactly what I want you to do. When you have heard the details you can decide better whether you want to go.”
Dr. Moorland had ceased pacing the room and settled deep in his comfortable study chair. With what seemed exasperating deliberateness to Jack, he removed his huge glasses and polished them thoroughly on his handkerchief before he was ready to talk. Then just as he[10] was about to begin he seemed to remember something else of importance, for he began to search drawer after drawer of his desk until he finally brought to light a large yellow envelope bulging with what appeared to be blueprints. He tossed the package on the desk before him and once again resumed his comfortable attitude.
“Perhaps you never heard of my nephew, Harry Ryder. In fact, I am quite certain you haven’t, for he has never visited Drueryville since you’ve been at school. Harry Ryder is the chief engineer of the enormous hydro-electric power plant at Necaxa where light and power is supplied for Mexico City, the capital, one hundred and twenty-five miles away. He was appointed to that important position by President Madero a year ago, and he has done his best to keep Mexico City lighted in spite of all the trouble in that turbulent republic, and the recent change to the Huerta régime.
“Time and again rebels have tried to break down the four transmission lines that carry the current to the city but they have never yet been successful and I judge from Harry’s letters[11] that he never intends they shall. But besides rebels, Harry has other important things to contend with. Up there in the mountains where the plant is located, thunderstorms are quite frequent and lightning is the troublesome element. Lightning is electricity in its most dangerous form, because of its very high voltage. Voltage, you know, is the pressure which causes it to travel. One of our scientists once tried to measure lightning and found that its voltage mounted well into the millions. This is tremendous force when you consider that the current used in lighting houses and stores is supplied at one hundred and ten volts.
“During thunderstorms the lightning plays about the transmission lines, often causing a great deal of trouble. If it should by any chance get into the station it would raise havoc with the generators and other machinery. To prevent this, lightning arresters have been constructed that will waylay the lightning, as it were, and send it into the ground before it reaches the vital machinery.”
Here Dr. Moorland paused and began to[12] sketch rapidly on a piece of paper while Jack looked on, still very much mystified.
 
Dr. Moorland’s Sketch
 
“The usual transformer is arranged something like this. First a choke coil is put in the transmission line near the end. When the lightning strikes this coil it piles up and is forced back exactly like a flying wedge of football players that suddenly tries to break through an impregnable defense. The lightning[13] that is thus forced back rushes into line ‘A,’ which is the point of least resistance, jumps the horn gap and plunges through the arrester tank and into the ground. When the excessive electricity has left the line and the flow is normal, the current is checked at the horn gap and arrested. This combination of gap and arrester does not permit current to flow into the ground during normal operation and does not actually become active until lightning gets into the line and there is danger of the plant being wrecked by an overload of electricity.”
“My, but that is interesting,” said Jack Straw as he fingered the master’s sketch. Indeed, he had been so carried away with the description of that interesting piece of engineering work that for the moment he had completely forgotten about Mexico. But Dr. Moorland revived his interest with his next sentence.
“And now for my reason for wanting you to go to Mexico. The lightning arresters now in use are not entirely satisfactory, and Harry Ryder has been trying to build one on completely[14] new lines. Indeed, he has perfected the contrivance, except for a neutral chemical solution of a new nature for which he asked me to construct a formula. He forwarded his drawings for me to look over and now I am ready to send them back. But a few weeks ago, Harry communicated with me and asked me to take particular care that the drawings reach him safely. In fact, he suggested that they be sent to him by messenger instead of by the mails. You see, Mexico is in a state of extended turmoil now with Villa, Carranza and Zapata all carrying on campaigns against Huerta, and under such conditions the mails are not trustworthy. In fact, I understand from Harry that three-quarters of the mail is destroyed by revolutionary forces and that the rest of it is left lying in almost any corner of the republic until it can be distributed.
“These drawings,”—Dr. Moorland fingered the bulky yellow envelope as he spoke,—“are far too valuable to trust to such mail service and since Harry is willing to meet the expenses of a messenger and at the same time pay him for his services, I can see no reason why[15] you should not be the one to take them safely to Necaxa.”
“Why, I’d be delighted with the undertaking, if you think I can do it satisfactorily,” said Jack.
“And why can’t you do it satisfactorily?” demanded the principal rather bruskly. “Any boy whom the students of Drueryville honor by electing captain of the football team for two successive seasons certainly must have some good qualities. You are strong and healthy. You are not a coward and above all you are reliable. These are qualifications that I could not find in every man. Will you go, Jack?”
“Yes, I will. When do I start?” asked the boy enthusiastically, and from the expression on his face it was evident that he was pleased with the confidence the old master had in his ability to carry out the mission.
“A steamer sails from New York on Saturday next. I would like to have you be on board when it leaves the dock for I am more than eager to have the drawings back to their owner and the responsibility off my mind.[16] Then, too, I am afraid the hostilities in Mexico might become more serious. You will have a week to prepare for the journey, and since I have looked up all your examination papers and found them above the proper rating I will excuse you from school for the last week of the term and you can spend that time with your father, for I know he has many things to say to you. You can leave Drueryville on the ten o’clock train to-morrow morning after you have called here to receive final instructions and the precious drawings. And now you must hurry back to your room and pack. Good afternoon and good luck to you.”
It was a rather serious moment for Jack when he shook hands with Dr. Moorland. He realized that the old schoolmaster was putting great trust in him. It was in truth a struggle for him to hide his emotions as he bade the old man good afternoon.