59297	----	YOUR TIME IS UP BY WALT SHELDON _The Colonel was a career man; and knowing what would happen within his lifetime promised to be an invaluable asset.... But he had never heard of that ancient legend of Faust...._ [Transcriber's Note: This etext was produced from Worlds of If Science Fiction, June 1955. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] At first I thought it was just another wrong number. Well, it was, in a sense--but not the kind of wrong number I thought it was. The ringing signal burred against my ear in the usual way, then there was a click, and somebody said, "Office of Historical Research. Zon Twenty speaking." "Oh. 'Scuse me," I said. "I must have dialed wrong." That was euphemism--misplaced loyalty, maybe. I didn't dial the wrong number, and I knew it. But high brass had installed a new automatic dialing system in the Pentagon as an economy measure, and it produced so many wrong numbers and entanglements that I think it actually must have cost more money in the long run than the old-fashioned live operator system--but then that shouldn't surprise you if you've ever been connected with the military. I was about to hang up after my apology. The voice on the other end said: "Wait! Did you say--_dialed_?" "Sure," I said. "Then--" and he seemed surprised, if not downright startled--"what kind of a phone are you speaking from?" "Huh?" I said. "What kind? The regular kind. Phone, desk, dial, M-1--or whatever the Army calls it." This time his voice went off like a small bomb. "The _Army_?" he said. "Sure," I said. "What's the matter with the Army?" And thought: Navy or Air Force type, no doubt. Our allies. Have to put up with them in the Pentagon. Have to put up with a lot of things--even being Colonel Lawrence Boggs didn't save you from a snafu dialling system. I thought: somebody is out to needle armchair colonels this week. I'll play around with it for a while, maybe find out who's got the sense of humor. The voice said, "Look here, are you joking with me?" "Perish it," I said. "But this talk about--about _dial_ phones. About _armies_. Why, you sound like one of those historical tri-vids about the twentieth century!" I smiled, without too much humor, shook my head at the phone, and said, "Look, fellow, come off it, will you? I haven't got time to play games." I hoped he wasn't some general or equivalent rank in a pixie mood. "Wait!" he said. "Wait--please--don't think off! Tell me, what year is it? Where you are, I mean." "What year? It's 1955, of course." "Why," he said, "this is remarkable!" "It is?" "Do you know what I think has happened? A quantum inversion." "Beg pardon?" I said. "Karpo Sixteen predicted the possibility just the other day! Listen, my friend, let me ask you just a few questions--" Then the mechanical voice of the operator cut in. It wasn't a real operator, of course, just a recorded voice, part of the new automatic system. These voices gave all the standard phrases and usually at the wrong time, the way the system was working. The worst of it was you couldn't argue with them or curse them--at least you always felt a little foolish afterward if you did. The operator's voice said, "_I'm sorry. Your time is up!_" "Now, wait!" said my communicant, his voice fading a little, "Don't cut us off! Don't think off yet!" Again: "_I'm sorry. Your time is up!_" And after that a click, and after that silence. I jiggled the hook a few times. No result. I shrugged. I hung up and rearranged the papers on my desk and went back to work, forgetting for the moment the party I'd been trying to call in the first place. And forgetting the odd conversation I had just had. No--not quite. Not quite forgetting it. Queerly, it clung to my mind. What had he said his name was? Zon Twenty. Sounded like that, anyway. Odd name. Of course I still thought it was a gag of some kind. Yet it bothered me. Zon's manner, his tone of voice had been so convincing. What he had said suggested that in some queer way I had managed to place a telephone call into the future. But as a sane, normal, recently promoted colonel, I knew this was impossible. At lunch I was still thinking about it. I ate in the officers' mess on my floor and steered my tray through the line. I saw, among other acquaintances Major "Clipper" Moskowitz at a far table, and remembered that he was a great science fan, always talking about rockets and reaching the moon, and that sort of thing--we had one argument about why a rocket works in a vacuum, such as space, and he hammered the table and drew diagrams and quoted Newton, and I'm still not convinced. Anyway, I went over and sat next to Clipper. "'Lo, Larry. How's it?" he said. "Routine," I said. "Latest request for overseas duty turned down. I'll probably die in the Pentagon with my pencil still behind my ear." We talked of such things for several minutes. "Clipper," I said finally, "you're the G.L.E. on this future science stuff--" "The what?" "Greatest Living Expert. Latest Pentagonese. Tell me, what do you think of the possibility of ever being in touch with the future?" "You mean time travel?" "I guess that's what you'd call it." "Time travel is nonsense," he said. "A logical absurdity. By definition, time is a series of infinitesimally small moments in succession. Once a point in time is established, it can't be changed, any more than energy can be destroyed." "I didn't say anything about changing anything. I was thinking about--well, talking with somebody in the future." "Just as paradoxical," he said, shrugging, and taking a huge bite of braised beef tongue. "If you go into the future--or talk to the future--the future affects the change, through you. In other words, if you can't go back into the past, neither can people from the future. And it's inconceivable that such a thing wouldn't make changes. Maybe only small ones, but they'd multiply in time. '_Thou canst not change a flower, without troubling of a star._' That's Francis Thompson. You step on one spider today, and you affect the evolution of spiders, the ecology of all other things in the distant future. By a simple act like that you could destroy or create a whole species to come." "My head swimmeth," I said. "All I want to know is--" He wasn't even listening to me. He enjoyed spouting this kind of thing. "Of course, it's theoretically possible for you to _witness_ events out of the past, without being party to them. If, for instance, you could travel away from Earth at more than the speed of light, overtaking the light waves of an event--say, the Monitor and Merrimac fight--" "Or the Battle of Gettysburg," I said, loyal to the core. "--you could look back and see it happen. The future? I doubt it. Unless in some way time and space actually curve back upon themselves, as some think." "Uh huh," I said, and drank my coffee and finally left Clipper Moskowitz. * * * * * After that I did manage to forget about Zon Twenty temporarily. It was a busy week. The draft quota had gone up, and Personnel Planning had worked out new criteria for classification, and I had to study these to apply them to analysis. This won't make much sense to you unless you've worked in a military headquarters yourself. I worked. I had a dim idea that if I worked hard enough somebody would favorably regard one of my requests to get sent overseas. I've got to explain something right here. I don't want anybody to get the idea I'm a hero type--a professional volunteer. But I'm a career officer, and overseas duty is the quickest way to tactical unit command, which is important on the record. The lack of it has kept many a perfectly good colonel from getting his first star and making that final big step. So I worked hard, and of course, sent in another request for transfer, this time under the provisions of a different set of regulations. And I didn't think about Zon Twenty again until about a week later, one afternoon, when the phone rang. "Personnel Analysis. Colonel Bog--" He didn't even let me finish. "Well! I've found you again! The man from the past!" "Oh, no," I said. "Don't tell me. Not Zon Twenty--" "Yes, it's I, of course! Seems we've had another lucky accident, and been connected again. I was despairing of it for a while. Now, for machine's sake, don't go away this time! I've _got_ to talk to you!" "It's your dime," I said. "Dime!" He pounced on it. "That was a monetary unit, when you had money, wasn't it?" "Look, mister--" "You haven't guessed what's happened, have you? We have it pretty well analyzed at this end. But we didn't really suppose your technology would be equal to it back there." "Look, just who are you, and where are you?" I said. "My name is Zon Twenty, as I told you. I'm an historical technician in the Office of Ancient Research in Washington, the capital of the planet, Earth. I'm an Earthman myself, of course. My job is to prepare studies of ancient civilizations such as yours--" "Now, wait--what kind of a gag is this?" "A gag? Oh--that's the ancient term for a joke. Good! I'll make a note of that!" "Come on. Who is it? Did Clipper Moskowitz put you up to this?" "Oh, dear," said Zon Twenty, and I could hear his heavy sigh. "I was afraid you wouldn't be able to grasp the situation. I'm going to have to offer proof, I suppose. Look here--exactly what date is it where you are?" "I told you. 1955." "I mean what month and year?" "It's August 23, 1955--and I think you know that as well as I do." "August 23. Just a minute ... we'll make a quick tape on the cyb, here. Ah, yes, here we are. August 23. All right. The nearest date of significance is September 1st. On the date twenty-one of your so-called nations reached--or should I say will reach--a new trade and tariff agreement in the U.N., and this will eventually lead directly to the free nation federation in--" "_I'm sorry! Your time is up!_" It was that blasted recorded voice of the mechanical operator again. "Hey! Don't cut us off!" I said. "Hello? Are you still with me? Look here--I'll try to call back! It's difficult, but I think I can!" said Zon Twenty. "_I'm sorry! Your time is up!_" And again the click, and silence. This time I didn't forget Zon Twenty, neither quickly nor easily. If it was a gag, it was a beauty: crazy and elaborate, and the acting was superb. If it wasn't a gag--well, I couldn't yet quite believe that it wasn't a gag. A week streamed by in a sea of paperwork. My latest overseas transfer request came back disapproved. Then, on the morning of September 2nd I opened the newspaper and saw the headline: TWENTY-ONE NATIONS REACH TRADE ACCORD IN U.N. I read the story. It was essentially what Zon had predicted--or remembered--or whatever you want to call it. I was confused now. That day I didn't work very well. I couldn't concentrate. I am not a deep thinker, and have no illusions that I am. But one idea presented itself, starting as kind of hypnotic little glow in the bottom of my mind, and this grew until I could scarcely think about anything else. Put it under the heading of temptation. Ask yourself if you would have been able to resist. Or just forget all the moral and ethical implications, and accept that I was tempted in this way. If I could be in touch with this Zon character--if he really was from the future, and an historical expert, at that--he could tell me all sorts of things that were going to happen. I could then either predict them or otherwise adjust my actions to fit them. I could go up so fast it would make Caesar's career look like a misfit reservist's. I could-- Well, then I started justifying and rationalizing. I could do my country all sorts of good. I thought along those lines for a while, and presently even managed to convince myself that my original purpose had been altruistic all along. Of course I tried to get in touch with Zon Twenty again. Over and over again I dialed the number I had dialed the first time I had become connected with him by apparent accident. I dialed random numbers. I listened to a long and boring dissertation on permutation of numbers by Clipper Moskowitz in an effort to devise a system of hitting all possible combinations. There were an awful lot of possible combinations. * * * * * My phone rang again nearly ten days later. It was Zon. He said, "Oh, _there_ you are! I'd about given up! Look--the quantum inversion is swinging back to normal! This is the last time we'll be able to talk! So we've got to make every moment count!" "Sure," I said. "You bet. Only I don't exactly get it. I don't understand just how all this happens. If you'd explain--" "That's not important. Briefly, we use telepathic induction for message selection. That's why I was startled when you mentioned the ancient dial phone. And of course we don't have armies any more." "Yes, but--" "Listen, Colonel--what was your name? Never mind. You can be most valuable to me in my research. You can supply details about your time that simply don't exist any more--" "Don't exist? Don't you have movies, recordings, magazines, all that stuff?" "Of course not. They were all destroyed in the Final War." "The what?" "The Final War. You'll hear about it soon enough. If you survive, that is. Only three hundred thousand did, out of the entire population. They were the seed of our present civilization." "Hey, now, wait a minute! What about this war? When was it? When's it going to be, I mean?" "There's no point in your asking," said Zon. "You can't change it, you know. If you could change it, I wouldn't be here. My world as I know it wouldn't exist. The fact that my time does exist proves, therefore, you never changed it. Now, if you'll just calm down--" "Calm down?" I shouted it across the centuries at him. "How can I? How would _you_ feel? Look, this Final War, as you call it. Is it going to be soon? You can at least tell me that, can't you?" "All right. Soon, as all time is reckoned. In your lifetime, I would say. Now, I suggest that you adjust yourself emotionally and accept what is inevitable. The best thing you can do is answer a few questions I've prepared." I took his advice. I calmed down. "Questions? Well, Mr. Zon, or whatever your name is, I'll tell you what I'll do. I'll make a bargain with you. I'll answer your questions if you'll answer mine. I'll tell you what's happening here--anything you want to know--if you look in that little file of yours and tell me what's _going_ to happen in my time. A deal?" He was silent for a moment, and at first I thought we'd been cut off again. "Hello? Zon? You still there?" "Yes, I'm still here." His voice had become oddly quiet. "So it's the old Faust legend all over again, is that it?" "I don't know what you're talking about," I said. I didn't--then. "You just answer my questions, and I'll answer yours. Mine first." "All right," he said. "Very well." And I started my barrage. When would the Final War start? He told me. How would it start? He told me that. Who would be the belligerents, and what weapons and techniques would be used at first, and what new ones would be developed? He knew. Where would the major campaigns be fought--how many troops would be involved? I got the whole story. I scribbled furiously and put it on paper. Afterwards, he asked his questions. They were innocuous, compared to mine. He wanted to know about taboos and marriage customs and slang expressions and education and eating habits and articles of clothing. I told him. I was in the midst of an explanation of the game of Bingo, of all things, when there was a sudden whooshing and crackling in the earpiece of the telephone. "Hello? Zon? Still with me?" "Yes--but I think the signal's going out. This may be the inversion passing! We probably won't be able to talk again. Hello? Do you still hear?" "I do. Look--one more thing before we go. You said this dictator--the one everybody hated so much--survived the final series of blasts. He and his staff. Where were they? Where were they when the blasts came?" "In a country at that time called Canada. Little place named Resolution, on Great Slave Lake. They'd dug in there--very elaborate underground installation." "And the date you gave me is correct?" "As far as I know. You're determined to be in that place at that time, I suppose." He seemed amused. "You can say that again," I said. There were more rumblings of static on the line. "Well, since you're so determined," said Zon Twenty, "one more word of advice. The dictator and all his followers were afterwards imprisoned by what populace remained. Small wonder, since they were mainly responsible for all the carnage. It was a pretty horrible thing. They were slowly and most savagely tortured continuously for nearly two decades. So if you mean to be there, at Great Slave Lake, I suggest you arrange to be on the right side." "Don't worry," I said. "I'll arrange it somehow. Larry Boggs is going to live through this, if anybody is--" "What's that? What's that you said?" "I said I'm going to live through this--" "No, no, the name. Boggs. Is that your name?" "Certainly that's my name. Colonel Lawrence E. Boggs, United States Army, and--" He was laughing. He was laughing loudly, uproariously, and, I thought, hollowly. The background noise in the receiver had been steadily getting worse. Now it swelled, like an angry sea. Interference of some sort snarled and crackled. A sick feeling began to grow like fungus in my stomach. Suddenly his voice came through again. He was still laughing. "Generalissimo Lawrence E. Boggs survived all right Colonel, he--" All the noise cut away suddenly. There was a pinpoint of silence. Then the mechanical operator: "I'm sorry! Your time is up!" 
32324	----	SAM, THIS IS YOU By MURRAY LEINSTER Illustrated by MEL HUNTER [Transcriber Note: This etext was produced from Galaxy Science Fiction May 1955. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] [Sidenote: Sam had led a peaceful and impecunious life--until a voice cut in on a phone and said: Sam, this is You] You are not supposed to believe this story, and if you ask Sam Yoder about it, he is apt to say that it's all a lie. But Sam is a bit sensitive about it. He does not want the question of privacy to be raised again--especially in Rosie's hearing. And there are other matters. But it's all perfectly respectable and straightforward. It could have happened to anybody--well, almost anybody. Anybody, say, who was a telephone lineman for the Batesville and Rappahannock Telephone Company, and who happened to be engaged to Rosie, and who had been told admiringly by Rosie that a man as smart as he was ought to make something wonderful of himself. And, of course, anybody who'd taken that seriously and had been puttering around on a device to make private conversations on a party-line telephone possible, and almost had the trick. It began about six o'clock on July second, when Sam was up a telephone pole near Bridge's Run. He was hunting for the place where that party line had gone dead. He'd hooked in his lineman's phone and he couldn't raise Central, so he was just going to start looking for the break when his phone rang back, though the line had checked dead. [Illustration] Startled, he put the receiver to his ear. "Hello. Who's this?" "Sam, this is you," a voice replied. "Huh?" said Sam. "What's that?" "This is you," the voice on the wire repeated. "You, Sam Yoder. Don't you recognize your own voice? This is you, Sam Yoder, calling from the twelfth of July. Don't hang up!" * * * * * Sam hadn't even thought of hanging up. He was annoyed. He was up a telephone pole, trying to do some work, resting in his safety belt and with his climbing irons safely fixed in the wood. Naturally, he thought somebody was trying to joke with him, and when a man is working is no time for jokes. "I'm not hanging up," said Sam dourly, "but you'd better!" The voice was familiar, though he couldn't quite place it. If it talked a little more, he undoubtedly would. He knew it just about as well as he knew his own, and it was irritating not to be able to call this joker by name. The voice said, "Sam, it's the second of July where you are, and you're up a pole by Bridge's Run. The line's dead in two places, else I couldn't talk to you. Lucky, ain't it?" [Illustration] "Whoever you are," Sam said formidably, "it ain't going to be lucky for you if you ever need telephone service and you've kept wasting my time. I'm busy!" "But I'm you!" insisted the voice persuasively. "And you're me! We're both the same Sam Yoder, only where I am, it's July twelfth. Where you are, it's July second. You've heard of time-traveling. Well, this is time-talking. You're talking to yourself--that's me--and I'm talking to myself--that's you--and it looks like we've got a mighty good chance to get rich." Then something came into Sam's memory and every muscle in his body went taut and tight, even as he was saying to himself, "It can't be!" But he'd remembered that if a man stands in a corner and talks to the wall, his voice will sound to him just the way it sounds to somebody else. Being in the telephone business, he'd tried it and now he did recognize the voice. It was his. His own. Talking to him. Which, of course, was impossible. "Look," said hoarsely, "I don't believe this!" "Then listen," the voice said briskly. And Sam's face grew red. It burned. His ears began to feel scorched. Because the voice--_his_ voice--was telling him strictly private matters that nobody else in the world knew. Nobody but himself and Rosie. "Quit it!" groaned Sam. "Somebody might be listening! Tell me what you want and ring off!" The voice told him what it wanted. His own voice. It sounded pleased. It told him precisely what it wanted him to do. And then, very kindly, it told him exactly where the two breaks in the line were. And then it rang off. * * * * * He sweated when he looked at the first of the two places. A joining was bad and he fixed that. It was where his voice had said it would be. And that was as impossible as anything else. When he'd fixed the second break, Sam called Central and told her he was sick and was going home, and that if there were any other phones that needed fixing today, people were probably better off without phone service, anyhow. He went home and washed his face, and made himself a brew of coffee and drank it, and his memory turned out to be unimpaired. Presently he heard himself muttering. So he said defiantly, "There ain't any crazy people in my family, so it ain't likely I've gone out of my head. But God knows nobody but Rosie knows about me telling her sentimental that her nose is so cute, I couldn't believe she ever had to blow it! Maybe it was me, talking to myself!" Talking to oneself is not abnormal. Lots of people do it. Sam missed out the conclusion to be drawn from the fact that he'd answered himself back. He reasoned painfully, "If somebody drove over to Rappahannock, past Dunnsville, and telephoned back that there was a brush fire at Dunnsville, I wouldn't be surprised to get to Dunnsville and find a brush fire there. So if somebody phones back from next Tuesday that Mr. Broaddus broke his leg next Tuesday--why, I shouldn't be surprised to get to next Tuesday and find he done it. Going to Rappahannock, past Dunnsville, and going to next Thursday, past next Tuesday, ain't so much difference. It's only the difference between a road-map and a calendar." Then he began to see implications. He blinked. "Yes, sir!" he said in awe. "I wouldn't've thought of it if I hadn't told myself on the telephone, but there _is_ money to be made out of this! I must be near as smart as Rosie thinks I am! I'd better get that dinkus set up!" He'd more or less half-heartedly worked out an idea of how a party-line telephone conversation could be made private, and just out of instinct, you might say, he'd accumulated around his house a lot of stuff that should have been on the phone company's inventory. There were condensers and transmitters and selective-ringing bells and resistances and the like. He'd meant to put some of them together some day and see what happened, but he'd been too busy courting Rosie to get at it. * * * * * Now he did get started. His own voice on the telephone had told him to. It had warned him that one thing he had intended wouldn't work and something else would. But it was essentially simple, after all. He finished it and cut off his line from Central and hooked this gadget in. He rang. Half a minute later, somebody rang back. "Hello!" said Sam, quivering. He'd broken the line to Central, remember. In theory, he shouldn't have gotten anybody anywhere. But a very familiar voice said "Hello" back at him, and Sam swallowed and said, "Hello, Sam. This is you in the second of July." The voice at the other end said cordially that Sam had done pretty well and now the two of them--Sam in the here and now and Sam in the middle of the week after next--would proceed to get rich together. But the voice from July twelfth sounded less absorbed in the conversation than Sam thought quite right. It seemed even abstracted. And Sam was at once sweating from the pure unreasonableness of the situation and conscious that he rated congratulation for the highly technical device he had built. After all, not everybody could build a time-talker! He said with some irony, "If you're too busy to talk--" "I'll tell you," replied the voice from the twelfth of July, gratified. "I am kind of busy right now. You'll understand when you get to where I am. Don't get mad, Sam. Tell you what--you go see Rosie and tell her about this and have a nice evening. Ha-ha!" "Now what," asked Sam cagily, "do you mean by that 'ha-ha'?" "You'll find out," said the voice. "Knowin' what I know, I'll even double it. Ha-ha, ha-ha!" There was a click. Sam rang back, but got no answer. He may have been the first man in history to take an objective and completely justified dislike to himself. But presently he grumbled, "Smart, huh? Two can play at that! I'm the one that's got to do things if we are both goin' to get rich." He put his gadget carefully away and combed his hair and ate some cold food around the house and drove over to see Rosie. It was a night and an errand which ordinarily would have seemed purely romantic. There were fireflies floating about, and the Moon shone down splendidly, and a perfumed breeze carried mosquitoes from one place to another. It was the sort of night on which, ordinarily, Sam would have thought only of Rosie, and Rosie would have optimistic ideas about how housekeeping could, after all, be done on what Sam made a week. They got settled down in the hammock on Rosie's front porch, and Sam said expansively, "Rosie, I've made up my mind to get rich. You ought to have everything your little heart desires. Suppose you tell me what you want so I'll know how rich I've got to get." * * * * * Rosie drew back. She looked sharply at Sam. "Do you feel all right?" He beamed at her. He'd never been married and he didn't know how crazy it sounded to Rosie to be queried on how much money would satisfy her. There simply isn't any answer to the question. "Listen," said Sam tenderly. "Nobody knows it, but tonight Joe Hunt and the Widow Backus are eloping to North Carolina to get married. We'll find out about it tomorrow. And day after tomorrow, on the Fourth of July, Dunnsville is going to win the baseball game with Bradensburg, seven to five, all tied till the ninth inning, and then George Peeby is going to hit a homer with Fred Holmes on second base." Rosie stared at him. Sam explained complacently. The Sam Yoder in the middle of the week after next had told him what to expect in those particular cases. He would tell him other things to expect. So Sam was going to get rich. Rosie said, "Sam! Somebody was playing a joke on you!" "Yeah?" Sam answered comfortably. "Who else but me knows what you said to me that time you thought I was mad at you and you were crying out back of the well-house?" "Sam!" "And nobody else knows about that time we were picnicking and a bug got down the back of your dress and you thought it was a hornet." "Sam Yoder!" wailed Rosie. "You never told anybody about that!" "Nope," said Sam truthfully. "I never did. But the me in the week after next knew. He told me. So he had to be me talking to me. Couldn't've been anybody else." Rosie gasped. Sam explained all over again. In detail. When he had finished, Rosie seemed dazed. Then she said desperately, "Sam! Either you've t-told somebody else everything we ever said or did together, or else--there's somebody who knows every word we ever said to each other! That's awful! Do you really and truly mean to tell me--" "Sure I mean to tell you," said Sam happily. "The me in the week after next called me up and talked about things nobody knows but you and me. Can't be no doubt at all." Rosie shivered. "He--he knows every word we ever said! Then he knows every word we're saying now!" She gulped. "Sam Yoder, you go home!" Sam gaped at her. She got up and backed away from him. "D-do you think," she chattered despairingly, "that I--that I'm g-going to talk to you when s-somebody else--listens to every w-word I say and--knows everything I do? D-do you think I'm going to _m-marry_ you?" Then she ran away, weeping noisily, and slammed the door on Sam. Her father came out presently, looking patient, and asked Sam to go home so Rosie could finish crying and he could read his newspaper in peace. * * * * * On the way back to his own house, Sam meditated darkly. By the time he got there, he was furious. The him in the week after next could have warned him about this! He rang and rang and rang, on the cut-off line with his gadget hooked in to call July the twelfth. But there was no answer. When morning came, he rang again, but the phone was still dead. He loaded his tool-kit in the truck and went off to work, feeling about as low as a man could feel. He felt lower when he reported at the office and somebody told him excitedly that Joe Hunt and the Widow Backus had eloped to North Carolina to get married. Nobody would have tried to stop them if they had prosaically gotten married at home, but they had eloped to make it more romantic. It wasn't romantic to Sam. It was devastating proof that there was another him ten days off, knowing everything he knew and more besides, and very likely laughing his head off at the fix Sam was in. Because, obviously, Rosie would be still more convinced when she heard this news. She'd know Sam wasn't crazy or the victim of a practical joke. He had told the truth. It wasn't the first time a man got in trouble with a woman by telling her the truth, but it was new to Sam and it hurt. He went over to Bradensburg that day to repair some broken lines, and around noon, he went into a store to get something to eat. There were some local sportsmen in the store, bragging to each other about what the Bradensburg baseball team would do to the Dunnsville nine. Sam said peevishly, "Huh! Dunnsville will win that game by two runs!" "Have you got any money that agrees with you?" a local sportsman demanded pugnaciously. "If you have, put it up and let somebody cover it!" Sam wanted to draw back, but he had roused the civic pride of Bradensburg. He tried to temporize and he was jeered at. In the end, philosophically, he dragged out all the money he had with him and bet it--eleven dollars. It was covered instantly, amid raucous laughter. And on the way back to Batesville, he reflected unhappily that he was going to make eleven dollars out of knowing what was going to happen in the ninth inning of that ball game, but probably at the cost of losing Rosie. * * * * * He tried to call his other self that night again. There was no more answer than before. He unhooked the gadget and restored normal service to himself. He rang Rosie's house. She answered the phone. "Rosie," Sam asked yearningly, "are you still mad at me?" "I never was mad at you," said Rose, gulping. "I'm mad at whoever was talking to you on the phone and knows all our private secrets. And I'm mad at you if you told him." "But I didn't have to tell him! He's me! All he has to do is just remember! I tried to call him last night and again this morning," he added bitterly, "and he don't answer. Maybe he's gone off somewheres. I'm thinking it might be a--a kind of illusion, maybe." "You told me there'd be an elopement last night," retorted Rosie, her voice wobbling, "and there was. Joe Hunt and the Widow Backus. Just like you said!" "It--it could've been a coincidence," suggested Sam, not too hopefully. "I'm--w-waiting to see if Dunnsville beats Bradensburg seven to five tomorrow, tied to the ninth, with George Peeby hitting a homer then with Fred Holmes on second base. If--if that happens, I'll--I'll die!" "Why?" asked Sam. "Because it'll mean that I can't m-marry you ever, because somebody else'd be looking over your shoulder--and we wouldn't ever be by ourselves all our lives--night or day!" She hung up, weeping, and Sam swore slowly and steadily and with venom while he worked to hook up his device again--which did not make a private conversation on a party line, but allowed a man to talk to himself ten days away from where he was. And then Sam rang, and rang, and rang. But he got no answer. The following day, in the big fourth of July game, Dunnsville beat Bradensburg seven to five. It was tied to the ninth. Then George Peeby hit a homer, with Fred Holmes on second base. Sam collected his winnings, but grimly, without joy. He stayed home that night, worrying, and every so often trying to call himself up on the device he had invented and been told--by himself--to modify. It was a nice gadget, but Sam did not enjoy it. It was a nice night, too. There was moonlight. But Sam did not enjoy that, either. Moonlight wouldn't do Sam any good so long as there was another him in the middle of the week after next, refusing to talk to him so he could get out of the fix he was in. * * * * * Next morning, though, the phone woke him. He swore at it out of habit until he got out of bed, and then he realized that his gadget was hooked in and Central was cut off. He made it in one jump to the instrument. "Hello!" "Don't fret," said his own voice patronizingly. "Rosie's going to make up with you." "How in blazes d'you know what she's going to do?" raged Sam. "She won't marry me with you hanging around! I've been trying to figure out a way to get rid of you--" "Quiet!" commanded the voice on the telephone irritably. "I'm busy. I've got to go collect the money you've made for us." "_You_ collect money? _I_ get in trouble and _you_ collect money?" "I have to," his voice said with the impatient patience of one speaking to a small idiot child, "before you can have it. Listen here. Where you are, it's Wednesday. You're going over to Dunnsville today to fix some phones. You'll be in Mr. Broaddus' law office about half-past ten. You look out the window and notice a fella setting in a car in front of the bank. Notice him good!" "I won't do it," said Sam defiantly. "I ain't taking any orders from you! Maybe you're me, but _I_ make money and _you_ collect it. For all I know you spend it before I get to it! I'm quitting this business right now. It's cost me my own true love and all _my_ life's happiness and to hell with you!" "You won't do it?" his own voice asked nastily. "Wait and see!" So, that morning, the manager told Sam, when he reported for work, to drive over to Dunnsville and check on some lines there. Sam balked. He said there were much more important lines needing repair elsewhere. The manager explained politely to Sam that Mr. Broaddus over in Dunnsville had been taken drunk at a Fourth of July party and fallen out of a window. He'd broken his leg, so it was a Christian duty to make sure he had a telephone in working order in his office, and Sam could get over there right away or else. On the way to Dunnsville, Sam morosely remembered that he'd known about Mr. Broaddus' leg. He had told himself about it on the telephone. At half-past ten, he was fixing Mr. Broaddus' telephone when he remembered about the man he was supposed to get a good look at, sitting in a car in front of the bank. He made an angry resolution not, under any circumstances, to glance outside of the lawyer's office. He meditated savagely that, by this resolution, the schemes of his other self in the future were abolished. Naturally, he presently went to the window and looked to see what he was abolishing. * * * * * There was a car before the bank with a reddish-haired man sitting in it. A haze came out of the exhaust, showing that the motor was running. None of this impressed Sam as remarkable. But as he looked, two other men came running out of the bank. One of them carried a bag and both of them had revolvers out and they piled into the car and the reddish-haired man gunned it and it was abruptly a dwindling speck in a cloud of dust, getting out of town. [Illustration] Three seconds later, old Mr. Bluford, president of the bank, came out yelling, and the cashier came after him, and it was a first-rate bank robbery they were yelling about. The men in the get-away car had departed with thirty-five thousand dollars. All of it had taken place so fast that Sam hardly realized what had happened when he went out to see what it was all about, and was instantly seized upon to do some work. The bankrobbers had shot out the telephone cable out of town with a shotgun, so word couldn't get ahead of them. Sam was needed to re-establish communications with the outside world. He did, absorbedly reflecting on the details of the robbery as he'd heard them. He was high up on a telephone pole and the sheriff and enthusiastic citizens were streaking past in cars to make his labors unnecessary, when the personal aspect of all this affair hit him. [Illustration] "Migawd!" gasped Sam, shocked. "That me in the middle of next week told me to come over here and watch a bank robbery! But he didn't let on what was going to happen so's I could stop it!" He felt an incredulous indignation come over him. "I woulda been a hero!" he said resentfully. "Rosie woulda admired me! _That other me is a born crook!_" Then he realized the facts. The other him was himself, only a week and a half distant. The other him was so far sunk in dastardliness that he permitted a crime to take place, feeling no more than sardonic amusement. And there was nothing he himself could do about it! He couldn't even tell the authorities about this depraved character! They wouldn't believe him unless he could get his other self on the telephone to admit his criminality. Even then, what could they do? Sam felt what little zest had been left in living go trickling out of his climbers. He looked into the future and saw nothing desirable in it. He painstakingly finished the repair of the shot-out telephone line, but then he went down to his truck and drove over to Rosie's house. There was but one thing he could do. * * * * * Rosie came suspiciously to the the door. "I come to tell you good-by, Rosie," said Sam. "I just found out I'm a criminal, so I aim to go and commit my crimes far away from my home and the friends who never thought I'd turn out this way. Good-by, Rosie." "Sam!" said Rosie. "What's happened now?" He told her about the bank robbery and how his own self--in the week after next--had known it was going to happen, and told Sam to go watch it without giving him information by which it could have been stopped. "He knew it after it happened," said Sam bitterly, "and he could've told me about it before! He didn't, so he's a accessory to the crime. And he is me, which makes me a accessory, too. Good-by, Rosie, my own true love! You'll never see me again!" "You set right down here," Rosie ordered firmly. "You haven't done a thing yet, so it's that other you who's a criminal. You haven't got a thing to run away for!" "But I'm going to have! I'm doomed to be a criminal! It's that me in the week after next! There's nothing to be done!" "Says who? _I'm_ going to do something!" "Like what?" asked Sam. "I'm going to reform you," said Rosie, "before you start!" * * * * * She was a determined girl, that Rosie. She marched inside and put on her blue jeans, then went to her father's woodshed where he kept his tools and got a monkey wrench and stuck it in her hip pocket. When she came to the truck, Sam said, "What's the idea, Rosie?" "I'm riding around with you," replied Rosie, with a grim air. "You won't do anything criminal with me on hand! And if that other you starts talking to you on the telephone, I'm going to climb that pole and tell him where he gets off!" "If anybody could keep me from turning criminal," acknowledged Sam, "it'd be you, Rosie. But that monkey wrench--what's it for?" Rosie climbed into the seat beside him. "You start having criminal ideas," she told him, "and you'll find out! Now you go on about your business and I and the monkey wrench will look after your morals!" This tender exchange happened only an hour or so after the robbery and there was plenty of excitement around. But Sam went soberly about his work as telephone lineman. Rosie simply rode with him as a--well, it wasn't as a bodyguard, but a sort of M.P. escort--Morals Police. Where he worked on a line, he called the central office to report, and he heard about the hunt for the bank robbers, and told Rosie. * * * * * It was good fortune that he'd been in Dunnsville when the robbery happened, because his prompt repair of the phone wires had spoiled the robbers' get-away plans. They hadn't gone ten miles from Dunnsville before somebody fired a load of buckshot at them as their car roared by Lemons' Store. They were past before they realized they'd been shot at. But the buckshot had punctured the radiator, and two miles on, they were stuck. They pushed their car off the road behind some bushes and struck out on foot, and the sheriff ran right past their car without seeing it. Then rain began to fall and the bank robbers were wet and scared and desperate. They knew there'd be roadblocks set up everywhere and they had that bag of money--part bills, but a lot of it silver--and all of Tidewater was up in arms. Taking evasive action, they hastily stuffed their pockets with small bills--there were no big ones--but dared not take too much lest the pockets bulge. They hid the major part of their loot in a hollow tree. They separated, going to nearby towns--while rain fell heavily and covered their trails--and went to bed with chest colds. They felt miserable. But the rain washed away the scent they had left and bloodhounds couldn't do a thing. None of this was known to Sam, of course. Rosie had taken charge of him and she kept charge. She rode with him all the afternoon of the robbery. When quitting time came, he took her home and prepared to retire from the scene. But she said grimly, "Oh, no, you don't! You're staying right here! You're going to sleep in my brother's room, and my pa is going to put a padlock on the door so you don't go roaming off to call up that no-account other you and get in more trouble!" "I might mess things up if I don't talk to him," Sam objected. "He's messed things up enough by talking to you! The idea of repeating our private affairs! He hadn't ought to know them! And I'm not sure," she said ominously, "that you didn't tell him! If you did, Sam Yoder--" Sam didn't argue that point, for there was no argument to make. He was practically meek until he discovered after supper that the schedule for the evening was a game of cribbage played in the living room where Rosie's mother and father were. He mentioned unhappily to Rosie that they were acting like old married people without the fun of getting that way, but he said that only once. Rosie glared at him. And when bedtime came, she shooed him into her brother's room and her father padlocked him in. He did not sleep well. * * * * * Next morning, there was Rosie in her blue jeans with a monkey wrench in her pocket, ready to go riding with him. She did. And the next day. And the next. Nothing happened. The state banking association put up five thousand dollars reward for the bank robbers and the insurance company put up some more, but there wasn't a trace of the criminals. There wasn't a trace of criminality about Sam, either. Rosie rode with him, but they exchanged not one single hand-squeeze, nor one melting glance, nor did they even play footsie while they were eating lunch in the truck outside a filling station. Their conduct was exemplary and it wore on Sam. Possibly it wore on Rosie, too. One day Sam said morosely, as he chewed on a ham sandwich at lunch, "Rosie, I'm crazy about you, but this feels like I been divorced without ever even getting married first." And Rosie snapped, "If I told you how I feel, that other you in the week after next would laugh his fool head off. So shut up!" Things were bad, and they got no better. For nearly a week, Rosie rode everywhere with Sam in his truck. They acted in a manner which Rosie's parents would in theory have approved, but didn't even begin to believe in. They did nothing the world could not have watched without their being embarrassed, and they said very little that all the world would not have been bored to hear. It must have been the eleventh of July when they almost snapped at each other and Rosie said bitterly, "Let me drive a while. I need to put my mind on something that it don't make me mad to think about!" "Go ahead," Sam invited gloomily. He stopped the truck and got out the door. "I don't look for any happiness in this world any more, anyway." He went around to the other side of the truck while she slid to the driver's seat. "Tomorrow's going to be the twelfth," she said. "Do you realize that?" "I hadn't given it much thought," admitted Sam, "but what's the difference?" "That's the day where the other you was when he called you up the first time." "That's right," said Sam morbidly. "It is." "And so far," added Rosie, jamming her foot viciously down on the accelerator, "I've kept you honest. If you change into a scoundrel between now and tomorrow--" She changed to second gear. The truck jerked and bounced. "Hey!" cried Sam. "Watch your driving!" "Don't you tell me how to drive!" "But if I get killed before tomorrow--" * * * * * Rosie changed gear again, but too soon. The truck bucked, and she jammed down the accelerator again, and it almost leaped off the road. "If you get killed before tomorrow," raged Rosie, "it'll serve you right! I've been thinking and thinking and thinking. And even if I stop you from being a crook, there'll always be that--other you--knowing everything we say and do." She was hitting forty miles an hour and speeding up. "So there'd still be no use. No hope, anyway." She sobbed, partly in fury and partly in grief. And the roadway curved sharply just about there and she swung the truck crazily around it--and there was a car standing only halfway off the road. [Illustration] Sam grabbed for the steering wheel, but there wasn't time. The light half-truck, still accelerating, hit the parked car with the noise of dozens of empty oil-drums falling downstairs. The truck slued around, bounced back, and then it charged forward and slammed into the parked car a second time. Then it stalled. [Illustration] Somebody yelled at Sam. He got out of the truck, looking at the damage and trying to figure out how it was that neither he nor Rosie had been killed, and trying worriedly to think how he was going to explain to the telephone company that he'd let Rosie drive. The voice yelled louder. Right at the edge of the woodland, there was a reddish-haired character screaming at him and tugging at his hip pocket. The words he used were not fit for Rosie's shell-like ears--even if they probably came near matching the way she felt. The reddish-haired man said more nasty words at the top of his voice. His hand came out of his hip pocket with something glittering in it. Sam was swinging when the glitter began and he connected before the gun fired. There was a sort of squashy, smacking sound and the reddish-haired man lay down quietly in the road. "Migawd!" said Sam blankly. "This was the fella in front of the bank! He's one of those robbers!" He stared. There was a loud crashing in the brushwood. The accident had happened at the edge of some woodland, and Sam did not need a high I.Q. to know that the friends of the red-haired man must be on the way. A second later, he saw them. Rosie was just getting out of the car then. She was very pale and there wasn't time to tell her to get started up if possible and away from there. One of the two running men was carrying a canvas bag with the words BANK OF DUNNSVILLE on it. * * * * * The men came at Sam, meanwhile expressing opinions of the state of things, of Sam, of the Cosmos--of everything but the weather--in terms even more reprehensible than the first man had used. They saw the reddish-haired man lying on the ground. One of them--he'd come out into the road behind the truck and was running toward Sam--jerked out a pistol. He was about to use it on Sam at a range of something like six feet when there was a peculiar noise behind him. It was a sort of hollow _klunk_ which, even at such a time, needed to have attention paid to it. He jerked his head around to see. The _klunk_ had been made by Rosie's monkey wrench, falling imperatively on the head of the second man to come out of the woods. She had carried it to use on Sam, but she used it instead on a total stranger. He fell down and lay peacefully still. Then Sam swung a second time, at the second man to draw a pistol on him. Then there was only the sweet singing of birds among the trees and the whirrings and other insect-noises of creatures in the grass and brushwood. Presently there were other noises, but they were made by Rosie. She wept, hanging onto Sam. He unwound her arms from around his neck and thoughtfully went to the back of the truck and got out some phone wire and his pliers. He fastened the three strangers' hands together behind them, and then their feet, and he piled them in the back of the light truck, along with the money they had stolen. They came to, one by one, and Sam explained severely that they must watch their language in the presence of a lady. The three were so dazed, though, by what had befallen them that the warning wasn't really necessary. Rosie's parents would have been pleased at how completely proper their behavior was, while they took the three bank robbers into town and turned them over to the sheriff. That night, Rosie sat out on the porch with Sam and they discussed the particular event of the day in some detail. But Rosie was still concerned about the other Sam. So Sam decided to assert himself. About half-past nine, he said firmly, "Well, Rosie, I guess I'd better be getting along home. I've got to try one more time to call myself up on the telephone and tell me to mind my own business." "Says who?" demanded Rosie. "You're staying locked up right here tonight and I'm riding with you tomorrow. If I kept you honest this far, I can keep it up till sundown tomorrow! Then maybe it'll stick!" Sam protested, but Rosie was adamant--not only about keeping him from being a crook, but from having any fun to justify his virtue. * * * * * She shooed him into her brother's room and her father locked him in. And Sam did not sleep very well, because it looked as though virtue wasn't even its own reward. He sat up, brooding. It must have been close to dawn when the obvious hit him. Then he gazed blankly at the wall and said, "Migawd! O'course!" He grinned, all by himself, practically from head to foot. And at breakfast, he hummed contentedly as he stuffed himself with pancakes and syrup, and Rosie's depressed expression changed to a baffled alarm. He smiled tenderly upon her when she came doggedly out to the truck, wearing her blue jeans and with the monkey wrench in her pocket. They started off the same as any other day and he told her amiably, "Rosie, the sheriff says we get five thousand dollars reward from the bankers' association, and there's more from the insurance company, and there's odd bits of change offered for those fellas for past performances. We're going to be right well off." Rosie looked at him gloomily. There was still the matter of the other Sam in the middle of the week after next. And just then, Sam, who had been watching the telephone lines beside the road as he drove, pulled off the road and put on his climbing irons. "What's this?" asked Rosie frightenedly. "You know--" "You listen," said Sam, completely serene. He climbed zestfully to the top of the pole. He hooked in the little gadget that didn't make private conversations possible on a party line, but did make it possible for a man to talk to himself ten days in the future. Or the past. "Hello!" said Sam, up at the top of the telephone pole. "Sam, this is you." A voice he knew perfectly well sounded in the receiver. "_Huh? Who's that?_" "This is you," said Sam. "You, Sam Yoder. Don't you recognize your own voice? This is you, Sam Yoder, calling from the twelfth of July. Don't hang up!" He heard Rosie gasp, all the way down there in the banged-up telephone truck. Sam had seen the self-evident, at last, and now, in the twelfth of July, he was talking to himself on the telephone. Only instead of talking to himself in the week after next, he was talking to himself in the week before last--he being, back there ten days before, working on this very same telephone line on this very same pole. And it was the same conversation, word for word. * * * * * When he came down the pole, rather expansively, Rosie grabbed him and wept. "Oh, Sam!" she sobbed. "It was you all the time!" "Yeah," said Sam complacently. "I figured it out last night. That me back there in the second of July, he's cussing me out. And he's going to tell you about it and you're going to get all wrought up. But I can make that dumb me back yonder do what has to be done. And you and me, Rosie, have got a lot of money coming to us. I'm going to carry on through so he'll earn it for us. But I'm warning you, Rosie, he'll be back at my house waiting for me to talk to him tonight, and I've got to be home to tell him to go over to your house. I'm goin' to say 'ha-ha, ha-ha' at him." "A-all right," said Rosie, wide-eyed. "You can." "But I remember that when I call me up tonight, back there ten days ago, I'm going to be right busy here and now. I'm going to make me mad, because I don't want to waste time talking to myself back yonder. Remember? Now what," asked Sam mildly, "would I be doing tonight that would make me not want to waste time talking to myself ten days ago? You got any ideas, Rosie?" "Sam Yoder! I wouldn't! I never heard of such a thing!" Sam looked at her and shook his head regretfully. "Too bad. If you won't, I guess I've got to call me up in the week after next and find out what's cooking." "You--you _shan't_!" said Rosie fiercely. "I'll get even with you! But you shan't talk to that--" Then she wailed. "Darn you, Sam! Even if I do have to marry you so you'll be wanting to talk to me instead of that dumb you ten days back, you're not going to--you're not--" Sam grinned. He kissed her. He put her in the truck and they rode off to Batesville to get married. And they did. But you're not supposed to believe all this, and if you ask Sam Yoder about it, he's apt to say it's all a lie. He doesn't want to talk about private party lines, either. And there are other matters. For instance, Sam's getting to be a pretty prominent citizen these days. He makes a lot of money, one way and another. Nobody around home will ever bet with him on who's going to win at sports and elections, anyhow. 
33154	----	THE TELEPHONE By Professor A. E. Dolbear _THE TELEPHONE_ With directions for making a Speaking Telephone Illustrated 50 cents _THE ART OF PROJECTING_ A Manual of Experimentation in Physics, Chemistry, and Natural History, with the Porte Lumière and Magic Lantern New Edition Revised Illustrated $2.00 _MATTER, ETHER, AND MOTION_ The Factors and Relations of Physical Science Illustrated $1.75 Lee and Shepard Publishers Boston THE TELEPHONE: AN ACCOUNT OF THE _Phenomena of Electricity, Magnetism, and Sound,_ AS INVOLVED IN ITS ACTION. WITH DIRECTIONS FOR MAKING A SPEAKING TELEPHONE. BY PROF. A. E. DOLBEAR, TUFTS COLLEGE, AUTHOR OF "THE ART OF PROJECTING," ETC. BOSTON: LEE & SHEPARD, PUBLISHERS. COPYRIGHT, 1877, BY A. E. DOLBEAR. PREFACE. THE popular exhibitions of the speaking-telephone during the past six months, together with numerous newspaper articles, have created a widespread interest in the instrument; and it has been thought that a small book explanatory of its action would meet a public want. It has seemed to be necessary to call attention to the various phenomena and inter-actions of the forces involved; and hence the author has attempted to make plain and intelligible the phenomena of electricity, magnetism, and sound. Cuts have been inserted where they could be useful in making the mechanical conditions more intelligible; and a table of tone-composition has been devised, which shows at a glance the constituents of the sounds of various musical instruments. As the speaking-telephone, in which magneto-electric currents were utilized for the transmission of speech and other kinds of sounds, was invented by me, I have described at some length my first instrument, and have also given explicit directions for making a speaking-telephone which I know, by trial, to be as efficient as any hitherto made; but nothing in the book is to be taken as a dedication of the invention to the public, as steps have already been taken to secure letters-patent according to the laws of the United States. A. E. DOLBEAR. COLLEGE HILL, MASS. THE TELEPHONE. ELECTRICITY. SOME of the phenomena of electricity are manifested upon so large a scale as to be thrust upon the attention of everybody. Thus lightning, which accompanies so many showers in warm weather in almost every latitude, has always excited in some individuals a superstitious awe, as being an exhibition of supernatural agency; and probably every one feels more or less dread of it during a thunder-shower, and this for the reason that it affects so many of the senses at the same time. The flash may be blinding to the eyes if near to us; the thunder may be deafening to the ears, and so powerful as to shake the foundations of the hills, and make the ground upon which we stand to sensibly move: these with the remembered destructive effects that have been witnessed, of buildings demolished and large trees torn to splinters in an instant, are quite sufficient to raise a feeling of dread in the strongest mind. In the polar regions, both north and south, where thunder-storms are less frequent, the atmospheric electricity assumes the form called the aurora borealis, or the aurora australis, according as it is seen north or south of the equator. More than two thousand years ago it was noticed by the Greeks that a certain kind of a mineral which was thrown up on the shores of the Mediterranean Sea, when rubbed would attract light bodies, such as shreds of silk or linen and bits of paper. To this substance they gave the name of Elektron, and the property developed thus by friction was afterwards called electricity. In 1600 Dr. Gilbert, physician to Queen Elizabeth, published a book in which he described numerous experiments demonstrating that electricity could be developed by friction upon a great variety of substances, such as stones, gems, and resins. The first machine for developing electricity was made by Otto von Guericke of Magdeburg, about 1680. His machine consisted of a ball of sulphur about six inches in diameter, which could be rotated. If the dry hand were held against the sulphur while it was being turned in a dark room, the sphere appeared to emit light: it also gave out a peculiar hissing or crackling sound. Newton experimented a little with electricity, and noticed that the rubber was an important element in developing electricity. He does not seem to have given to the subject the same attention that he gave to some other departments of science. Had he done so, it is probable that he would have advanced the study a hundred years; that is to say, he would probably have left it at the place where it actually was in 1790. So great were his abilities that in one lifetime he made greater additions to human knowledge than all the rest of mankind had made during the preceding thousand years. In the month of June, 1752, Franklin made that memorable experiment which immortalized him. He flew his kite to the thunder-cloud, practically asking the question of the lightning whether or not it was identical with electricity. The lightning came down the wetted twine to his hand, and proclaimed its identity. For the next forty years the natural philosophers in both Europe and America only rung the changes upon what was known. They flew kites to the clouds; they made and charged Leyden jars, and discharged them through wires and chains and circuits of clasped hands, and studied the attractions and repulsions manifested by electrified bodies; but they added nothing of importance in the way of experiments. In 1791 Galvani, a professor of anatomy at Bologna, announced a manifestation of electricity that was new and of a remarkable character, having its origin in the muscles of animals, and so was called animal electricity. He had some frogs' legs prepared for eating; by chance they were placed near an electrical machine with which Galvani was experimenting, so that a spark would occasionally pass to the legs, when they would contract as often as a spark passed to them. The motion was first observed by his wife, who called his attention to the phenomenon; and he very soon discovered that the thighs of a frog, skinned and suspended, made a very good electroscope. While experimenting in this way he made another and more important discovery; namely, that, when the muscles and nerves of the frog's leg were touched by pieces of two different metals, the leg would contract as before. Alexander Volta, another Italian professor, who had invented the electrophorus, and was possessed of great experimental skill, now turned his attention to the experiment of Galvani, and very soon discovered that the origin of the electricity that moved the frogs' legs was not in the legs themselves, but in the metals used. The first form of the galvanic battery was the result of Volta's investigations, and was called the Voltaic pile. This pile consisted of alternate disks of zinc, flannel, and copper, piled one on top of the other in constant succession in that order. The flannel was moistened with salt and water, or with diluted sulphuric acid. When the first zinc was connected with the last copper by means of a wire, a powerful current of electricity was obtained. This form of battery is not in use at all now, as much more efficient means are known for producing electricity; but this in 1800, when it was first made known in England, was very startling, and was one of those surprises which have been so frequent since then in the history of electricity. Surprising things were done by Sir Humphry Davy, with a large Voltaic battery. Water was decomposed, and the metals potassium and sodium were first separated from their compounds with oxygen. Bonaparte had offered a prize of sixty thousand francs "to the person who by his experiments and discoveries should advance the knowledge of electricity and galvanism as much as Franklin and Volta did," and of "three thousand francs for the best experiments which should be made in each year on the galvanic fluid." This latter prize was awarded to Davy. After Davy's successes in 1806, there was nothing of importance in an experimental way added to the knowledge of electricity, until 1820, when Oersted of Copenhagen announced that "the conducting wire of a Voltaic circuit acts upon a magnetic needle," and that the needle tends to set itself at right angles to the wire. This was a kind of action altogether unexpected. This observation was of the utmost importance; and at once the philosophers in Europe and America set themselves to inquire into the new phenomenon. The laws of the motion of the magnetic needle when acted upon by a current of electricity traversing a wire were successfully investigated by M. Ampère of the French Academy. He observed that whenever a wire through which a current of electricity was passing was held over and parallel with a magnetic needle which was free to move, and therefore pointed to the north, if the current was moving _towards_ the north, the north pole was deflected to the west; if the current was moving towards the south, the south pole of the magnet was deflected towards the west; and that in all cases the magnet tended to set itself at right angles to the current; also that this angular displacement depended upon the strength of the current. Thus originated the _galvanometer_, an instrument that not only detects the existence of an electric current, but enables us to determine its direction and its strength. Our present knowledge of electrical laws is due, in a very large measure, to observations made with this instrument. Of course it has been very much modified, and made almost incredibly sensitive: yet, in all galvanometers, the fundamental principle involved in their structure is that of the action of a current of electricity upon a magnet, which was first noticed by Oersted. MAGNETS. It is related by Nicander that among the shepherds who tended their flocks upon the sides of Mount Ida was one named Magnes, who noticed, that, while taking his herds to pasture, his shepherd's crook adhered to some of the rocks. From this man's name some have supposed the name _magnet_ to have been derived. It is, however, generally believed to have received its name from the ancient city of Magnesia in Asia Minor, near which the loadstone or magnetic substance was found. This rock, which possesses the remarkable property of attracting and holding to itself small pieces of iron or steel, is now known to be one of the ores of iron, and is called magnetite by mineralogists. The iron is chemically combined with oxygen, and forms 72.5 per cent of its weight. There is another ore of iron, known as hematite, which contains seventy per cent of iron; but the difference of two and a half per cent of iron in the ore is enough to make the difference between a magnetically inert substance, and one which may be able to lift a mass of iron equal to many times its own weight. Sir Isaac Newton is said to have worn in a finger-ring a small loadstone weighing three grains, which would lift seven hundred and fifty grains, which is equal to two hundred and fifty times its own weight. The most powerful magnet now known is owned by M. Obelliane of Paris. It can lift forty times its own weight. Large pieces, however, do not support proportionally greater weights, seldom more than one or two times their own weight. There are in many places in the world immense beds of magnetic iron-ore. Such are to be found in the Adirondack region in Northern New York, and in Chester County, Pennsylvania. The celebrated iron-mines of Sweden consist of it, and in Lapland there are several large mountains of it. It must not be inferred, that, because the mineral is called magnetite, all specimens possess the property called magnetism. The large masses seldom manifest any such force, any more than ordinary pieces of iron or steel manifest it: yet any of it will be attracted by a magnet in the same way as iron will be. The most powerful native magnets are found in Siberia, and in the Hartz, a range of mountains in Northern Germany. When a piece of this magnetically endowed ore is placed in a mass of iron-filings, it will be seen that the filings adhere to it in greatest quantity upon two opposite ends or sides, and these are named the poles of the magnet. If the piece be suspended by a string so as to turn freely, it will invariably come to rest with the same pole turned towards the north; and this pole is therefore called the north pole of the magnet, and the action is called the directive action. This directive action was known to the Chinese more than three thousand years ago. In traversing those vast steppes of Tartary they employed magnetic cars, in which was the figure of a man, whose movable, outstretched arm always pointed to the south. Dr. Gilbert affirms that the compass was brought from China to Italy in 1260, by a traveller named Paulus Venetus. When a piece of hardened steel is rubbed upon a natural magnet, it acquires the same directive property; and, as the steel could be easily shaped into a convenient form for use, a steel needle has generally been used for the needle of a compass. The directive power of the magnet has been and still is of incalculable value to all civilized nations. Ocean navigation would be impossible without it, and territorial boundaries are fixed by means of it; but there are other properties and relations of a magnet, which have been discovered within the last fifty years, which are destined to be as important to mankind as that of the compass has been. In 1825 William Sturgeon of Woolwich, Eng., discovered that if a copper wire were wound around a piece of soft iron, and a current of electricity sent through the wire, the soft iron would become a magnet, but would retain its magnetism no longer than while the current of electricity was passing through the coil. The magnetism developed in this way was called electro-magnetism, and the iron so wound was called an electro-magnet. The first electro-magnet was made by winding bare wire upon the soft iron. This method will not produce very strong magnets. In 1830 Prof. Henry insulated the wire by covering it with silk, and was the first to produce powerful magnets. On a soft iron bar of fifty-nine pounds weight he used twenty-six coils of wire, thirteen on each leg, all joined to a common conductor by their opposite ends, and having an aggregate length of seven hundred and twenty-eight feet. This apparatus was found able to sustain a weight of twenty-five hundred pounds. This electro-magnet is now owned by Yale College. The power of the electro-magnet is enormously greater than that of any permanent magnet. A permanent magnet made by Jamin of Paris, which is made up of many strips of thin steel bound together, and weighing four pounds, is able to support a weight of one hundred pounds; but Dr. Joule made an electro-magnet, by arranging the coils to advantage, that would support thirty-five hundred times its own weight, or one hundred and forty times the proportionate load of Sir Isaac Newton's ring magnet. THE GALVANIC BATTERY. The original form of the galvanic battery as devised by Volta, and modified but little during thirty years, consisted of a cell to contain a fluid, which was usually dilute sulphuric acid, in which two plates of different metals were immersed: the metals used were generally plates of zinc and copper, or zinc and silver. Such plates, when first placed in the liquid, will give a very good current of electricity; but it will not last long. The reason of this is easy to understand. Whenever a current of electricity is generated by chemical action of a liquid upon two different metals, there is always some decomposition of the liquid, and this decomposition takes place upon the plates themselves; and the liberated gases _adhere to the plates, and prevent further contact with the acid_; at the same time, the gases themselves act upon the plates, and generate a current of electricity in the opposite direction. This will of course interfere with the first current; and very soon the battery is useless until the plates have been withdrawn from the liquid. This physico-chemical process that takes place in such a battery is called the _polarization of the plates_. [Illustration: FIG. 1.] The accompanying figure will help one to understand the actions going on in a battery cell of the kind mentioned. Let Pt represent a plate of platinum, and Zn a plate of zinc, both placed in a vessel containing hydrochloric acid, which is also represented by the symbols HCl. As such molecules are extremely minute, there will of course be an immense number of them between the plates. The plates are now to be connected by a wire running between them through the air. As soon as these conditions are fulfilled, a hissing sound will be heard coming from the cell, and bubbles of gas will be seen to rise from the platinum plate: these bubbles prove upon analysis to be bubbles of hydrogen. At the same time the zinc will begin to dissolve, forming what proves by analysis to be the chloride of zinc; and at the same time a current of electricity travels through the wire from the platinum to the zinc. The quantity of electricity that is thus generated is strictly proportionate to the quantity of hydrogen liberated, which is also proportionate to the weight of zinc dissolved; and this, in turn, is proportionate to the surface of the metals exposed to the action of the acid. Now, it happens under such circumstances as the above, that the liberated hydrogen adheres very strongly to the platinum, as there is nothing for it to unite with chemically; and therefore the plate will very soon be visibly covered with bubbles, which may be scraped off with a feather or a swab, but only to have the same thing repeated. This coating of bubbles will prevent the acid from touching the plate, and so practically diminishes the surface of it; but the quantity of electricity generated being proportionate to the surface exposed to the chemical action, it will be understood at once how such polarization of the plates must soon bring the battery to a standstill. In 1836 Prof. J. F. Daniell of London contrived a battery, which has been called the Daniell Cell, in which the metal (copper) that had the hydrogen liberated upon it was separated by a porous cell from the zinc. The zinc was immersed in dilute sulphuric acid, and the copper in an acid solution of blue vitriol (copper sulphate). The porous cup did not prevent the electricity from passing, nor the decomposition from taking place; but the hydrogen, which in this case would have been liberated at the copper plate, at once united with oxygen there, which it got by decomposing the copper sulphate: hence water was formed, and copper was deposited upon the copper plate; and, being an excellent conductor, the battery would keep up a strong action for a long time. Mr. Grove, also of London, in 1839 invented a battery which still goes by his name, in which the hydrogen plate is of platinum immersed in strong nitric acid, enclosed also in a porous earthen cell; and this, in turn, is plunged into a vessel containing dilute sulphuric acid and the zinc. In this case the liberated hydrogen immediately decomposes the nitric acid, which readily parts with its oxygen; water is the product, as in the other case, and the nitric acid loses strength. Strips of carbon have been substituted for the platinum, and this is called the Bunsen battery. It is otherwise like the Grove battery; it gives a very powerful and constant current and it is by the use of one or the other of these batteries, that most of the experiments in electricity are performed in institutions of learning, and, until lately, most in use for telegraphic purposes. OTHER MEANS FOR GENERATING ELECTRICITY. THERMO-ELECTRICITY. IF two strips of different metals, such as silver and iron, be soldered together at one end, and the other ends be connected with a galvanometer, on heating the soldered junction of the metals it will be found that a current of electricity traverses the circuit from the iron to the silver. If other metals be used, having the same size, and the same degree of heat be applied, the current of electricity thus generated will give a greater or a less deflection, which will be constant for the metals employed. The two metals generally employed are bismuth and antimony, in bars about an inch long and an eighth of an inch square. These are soldered together in series so as to present for faces the ends of the bars, and these often number as many as fifty pairs. Such a series is called a thermo-pile. This method of generating electricity was discovered by Seebeck of Berlin in 1821, but the thermo-pile so much in use now in heat investigations was invented by Nobili in 1835. The strength of this current is not very great, a single Daniell cell being equal to nine pairs of the strongest combination yet discovered, namely, the artificial sulphuret of copper with German silver. MAGNETO-ELECTRICITY. [Illustration: FIG. 2.] It has already been mentioned, that Oersted found that a magnet when free to turn tended to set itself at right angles to a wire in which a current of electricity was passing, thus demonstrating some inter-action between electricity and magnetism; but it remained for Faraday to discover the converse fact, namely, that a magnet moving across a wire, the ends of which were connected with a galvanometer or otherwise closed, originated a current of electricity in the wire, the direction of which depended upon the direction of the movement of the magnet. If the wire was coiled into a hollow helix, the magnet in moving through the helix moved across, that is, at right angles to all the turns of the helix; and each complete turn added to the intensity of the current. This will be understood by reference to the diagram, Fig. 2. Let G be a galvanometer connected with the wires from a helix; N S, a permanent bar magnet. If the magnet be thrust into the coil, a current of electricity will traverse the helix, wire, and galvanometer, and the needle will indicate its direction. If the magnet be now withdrawn, a current will move in the opposite direction through the whole circuit. The electricity that is thus originated is said to be induced. The quantity of electricity that can be induced thus is almost unlimited, depending upon the size and strength of the magnet, the size of the wire, and the length of wire in the coil. There are now many forms of machines for developing electricity from the motion of coils of wire in front of the poles of permanent magnets. They are generally called magneto-electric machines. The action involved in these machines is so important in its bearing upon telephony as to necessitate a fuller description of them. MAGNETIC INDUCTION. [Illustration: FIG. 3.] Let N S, Fig. 3, be a bar of hardened steel rendered permanently magnetic. If now there be brought near to it a board-nail, the latter will become a magnet through the _inductive_ action of the first magnet. This induced magnetism may be demonstrated by bringing a tack or other bit of iron to the end that is farthest from the permanent magnet; the tack will adhere to the nail, but will fall off when the nail is removed from the neighborhood of the magnet. By testing the polarity of the nail, it will be found that the end nearest the magnet will be a south pole if the magnet has its north pole towards it, in all cases having a polarity opposite to that of the pole acting upon it. The strength of this induced magnetism thus developed depends upon the distance apart of the magnet and the iron, being at its maximum when the two touch. But the tack itself is also made a magnet, and will attract another tack, and that one still another, the number which can be thus supported being dependent upon the strength of the first or inducing magnet. Suppose now that we should wind a few feet of wire about the nail, and fasten the two ends of the wire to an ordinary galvanometer, and then make the nail to approach the permanent magnet. The galvanometer needle would be seen to move as the nail approached; and, if the latter were allowed to touch the magnet, the movement of the needle would suddenly be much hastened, but would directly come to rest, showing that, so long as there is no motion of the nail towards or away from the magnet, no electricity is moving in the wire, although the nail is a strong magnet while it is in contact with the permanent magnet. If the nail be now withdrawn, the two phenomena happen as before: that is to say, as the nail recedes it loses its magnetism; and the giving-up of its magnetism induces a current of electricity through the wire in the opposite direction to that it had when the nail approached. The current of electricity in the opposite direction is indicated by the galvanometer needle, which moves according to Ampère's law mentioned on a preceding page. It may be noted here that we have an effect quite analogous to that already mentioned on page 21 as the experiment of Faraday. In one case a permanent magnet is thrust into a coil of wire, and in the other a piece of iron is made a magnet while enclosed in a coil. In each case there is generated a current of electricity _which lasts no longer than the mechanical motion of the parts lasts_. MAGNETO-ELECTRIC MACHINES. Such transient currents are practically useless, and several devices have been invented to make the flow continuous. The common form of machine for doing this may be understood by reference to the diagram. [Illustration: FIG. 4.] N S, Fig. 4, is the permanent magnet, which is bent into a U form in order to utilize both poles. N´ and S´ are short rods of soft iron fastened into a yoke-piece Y, also of soft iron. Coils of wire surround each of the rods as represented, the ends of the wires connecting with each other and with what is called a pole-changer. The whole of this part is capable of revolving upon an axis P Y by a pulley at P. The action is as follows: From their position, the soft-iron rods N´ S´ must be magnets through the inductive action of the permanent magnet, just as the nail was made a magnet in like position. So long as the parts have the relative position shown in the figure, and there is no motion, no electricity can be developed; but, if the axis P Y be turned, S´, which represents the polarity of the rod opposite N, will be losing its induced magnetism; and, when half a revolution has been made, that same pole will be where N´ now is; but it will then have N´ polarity instead of S´; that is, it has been losing south polarity as it receded from N, and gaining north polarity as it approached S: hence a current of electricity has steadily been flowing through the coil in one direction. At the same time, the other rod N´ has passed through similar phases; and its enveloping coil has had a current of electricity induced in it in the same direction as in the first coil. This doubles the intensity of the current; and the whole is conducted by the connecting-wires where the current is wanted. Machines have been built upon this plan, that contained fifty or sixty powerful compound permanent magnets, and as many wire coils, needing a steam-engine of eight or ten horse-power to run them. A less cumbersome and much more efficient magneto-electric machine has been made by changing the form of the soft iron armature to something like a shuttle, and winding the wire inside of it. This is called the "Siemen's Armature." The latest pattern of such machines is known as the _Gramme_; and its peculiarity consists in the substitution of a broad ring of soft iron for the armature. About this ring a good many coils, of equal lengths, of insulated copper wire are wound in such a manner that one-half of any turn in the wire goes through the inside of the ring, making the coils longitudinal. The whole of the armature thus prepared is fixed upon a shaft, so as to permit rotation, and fixed between the poles of a powerful Jamin magnet. The ends of the coils are connected with conductors upon the axis; and, when the armature thus constructed is rotated, a very constant and powerful current of electricity flows in a single direction, unlike the other forms. It is stated, that, with one-horse power, a light can be obtained equal to that from a battery of fifty Grove cells. SECONDARY CURRENTS. So long ago as 1836 it was noticed by Prof. Page of Salem, that, whenever a current of electricity was made to flow in a coil of wire, another current in the opposite direction was induced in a coil that was parallel with the first; and also, when the current in the first was broken, another current in the second coil would flow in the opposite direction to the former one. These currents, which are called secondary currents, are very transient. No current at all flows save at the instant of making or breaking the current. In this respect, we are reminded of the behavior of the soft iron within the coil, which gives origin to a current of electricity when it is made to approach a magnet or recede from it, but gives no current so long as it is still. These secondary currents were investigated by Prof. Henry, resulting in the discovery of many curious and interesting phenomena. It will be sufficient here for me to refer to what are called induction coils, which are developments of the principles involved in electro-magnetism and electro-induction. Imagine a rod of soft iron of any size to be wound with a coil of wire, the ends of the wire to be so left that they may be connected with a galvanic battery. Around this coil let another coil be wound of very fine and well-insulated wire; the terminal wires of it to be left adjustable to any distance from each other. Now, upon making connection with a battery to the primary coil, there will be two results produced simultaneously. First, the soft iron will be rendered magnetic; and, second, a current of electricity will be generated in the secondary coil; and the strength of this secondary current is very much increased by the inductive action of the soft iron that has been made a magnet. When the battery current is broken, the iron loses its magnetism, and a current of electricity is again started in the secondary coil in the opposite direction. The energy of this derived current is so great that it will jump some distance through the air, and thus is apparently unlike the electricity that originates in a battery. An induction coil made by Mr. Ritchie for the Stevens Institute at Hoboken, N.J., has a primary coil of 195 feet of No. 6 wire. The secondary coil is over fifty miles in length, and is made of No. 36 wire, which is but .005 of an inch in diameter. This instrument has given a spark twenty-one inches in length, with three large cells of a bichromate battery. Mr. Spottiswood of London has just had completed for him the largest induction coil ever made. It has two primary coils, one containing sixty-seven pounds of wire, and the other eighty-four pounds, the wire being .096 inch in diameter. The secondary coil is two hundred and eighty miles long, and has 381,850 turns. This coil is made in three parts, the diameter of the wire in the first part being .0095 inch; of the second part, .015; and the third part, .011. With five Grove cells this induction coil has given a spark forty-two inches long, and has perforated glass three inches thick. The electricity thus developed in secondary coils is of the same character as that developed by friction; and all of the experiments usually performed with the latter may be repeated with the former, many of them being greatly heightened in beauty and interest. Such, for instance, are the discharges in vacuo in Geisler tubes, exhibiting stratifications, fluorescence, phosphorescence, the production of ozone in great quantity, decomposition of chemical compounds, &c. The electricity developed by friction upon glass, wax, resin, and other so-called non-conductors, has heretofore been called static electricity, for the reason that when it was once originated upon a surface it would remain upon it for an indefinite time, or until some conducting body touched it, and thus gave it a way of escape. Thus, a cake of wax if rubbed with a piece of flannel, or struck with a cat-skin or a fox-tail becomes highly electrified, and in a dry atmosphere will remain so for months. Common air has, however, always a notable quantity of moisture in it; and, as water is a conductor of electricity, such damp air moving over the electrified surface will carry off very soon all the electricity. Again, the electricity developed through chemical action in a battery and through the inter-action of magnets and coils of wire has been called dynamic electricity, inasmuch as it never appeared to exist save when it was in motion in a completed circuit. This, however, is not true; for if one of the wires from a galvanic battery be connected with the earth, and the other wire be attached to a delicate electrometer, it will be found that the latter gives evidence of electrical excitement in the same manner as it does for the electricity developed by friction in another body. This is sometimes called _tension_, and is very slight for a single cell; but in a series of cells it becomes noticeable in other ways. Thus when the terminals of a single cell are taken in the hands, no effect is perceived: if, however, the terminals of a battery consisting of forty or fifty cells be thus taken, a decided shock is felt, not to be compared though with the shock that would be felt from the discharge of a very small Leyden jar. The shock from several hundred cells would be very dangerous. It was formerly doubted that the electricity would pass between the terminals of a battery without actual contact of the terminals. Gassiot first showed that the spark would jump between the wires of a battery of a large number of cells before actual contact was made. Latterly Mr. De La Rue has been measuring the distance across which the spark would jump, using a battery of a large number of cells. I give his table as taken from the "Proceedings of the Royal Society:"-- Cells. Striking distance. 600 .0033 inch. 1,200 .0130 " 1,800 .0345 " 2,400 .0535 " This table shows that the striking distance is very nearly as the square of the number of cells. Thus, with 600 cells the spark jumped .0033 inch; and with double the number of cells, 1,200, the spark jumped .0130 inch, or within .0002 of an inch as far as four times the first distance. This leads one to ask how big a battery would be needed to give a spark of any given length, say like a flash of lightning. One cell would give a spark .00000001 inch long, and a hundred thousand would give a spark 92 inches long. A million cells would give a spark 764 feet long, a veritable flash of lightning. It is hardly probable that so many as a million cells will ever be made into one connected battery, but it is not improbable that a hundred thousand cells may be. De La Rue has since completed 8,040 cells, and finds that the striking distance of that number is 0.345 inch, a little more than one-third of an inch. He also states that the striking distance increases faster than the above indicated ratio, as determined by experimenting with a still larger number of cells. These experiments and many others show that there is no essential difference between the so-called static and dynamic electricity. In the one case it is developed upon a surface which has such a molecular character that it cannot be conducted away, every surface molecule being practically a little battery cell with one terminal free in the air, so that when a proper conductor approaches the surface it receives the electricity from millions of cells, and therefore becomes strongly electrified so that a spark may at once be drawn from it. WHAT IS ELECTRICITY? THEORIES. NUMEROUS attempts have been made to explain the phenomena of electricity. As a general thing, these phenomena are so utterly unlike other phenomena that have been explained and are easily intelligible, that it has quite generally been taken for granted, until lately, that something very different from ordinary matter and the laws of forces applicable to it must be involved in the phenomena themselves. Consequently the term _imponderable_ was applied to it,--something that was matter minus some of the essentials of matter; and as it was apparent that, whatever it was, it moved, apparently flowed, from one place to another, the term _fluid_ was applied to it, a term descriptive of a certain form of matter. Imponderable fluid was the descriptive name applied to electricity. Newton supposed that an excited body emitted such a fluid that could penetrate glass. When the two facts of electrical attraction and repulsion had to be accounted for, two theories were propounded,--one by Benjamin Franklin, the other by Dufay. Franklin supposed that electricity was a subtle, imponderable fluid, of which all bodies contained a certain normal quantity. By friction or otherwise this normal quantity was disturbed. If a body received more than its due share, it was said to be positively electrified: if it had less than its normal quantity, it was said to be negatively electrified. Franklin supposed this electric fluid to be highly self-repulsive, and that it powerfully attracted the particles of matter. According to Dufay, there are two electric fluids, opposite in tendency but equal in amount. When associated together in equal quantities, they neutralize each other completely. A portion of this neutral compound fluid pervades all matter in its unexcited state. By friction or otherwise this compound fluid is decomposed, the rubber and the body rubbed exchanging equal quantities of opposite kinds with each other, leaving one of them positively, the other negatively electrified. These two fluids were supposed to be self-repulsive, but to attract each other: so that, if two bodies be charged with either positive or negative electricity, such bodies would mutually repel each other; but if one was charged with positive, while the other was charged with negative electricity, the two bodies would mutually attract each other. Either of these two theories may be used to illustrate the phenomena, and so have done good service in systematizing the facts. It is evident that both of them cannot be true, and it is in the highest degree probable that neither of them is true. Some have supposed that there was a kind of electric atmosphere about every atom of matter; and still another theory, now advocated by Edlund of Stockholm, assumes that electricity is identical with the ether by which radiant energy, light and heat, is transmitted. Before a correct judgment can be formed of the nature of any force, it is necessary to know what it can do, what kind of phenomena it can produce. Let us, then, take a brief survey of what electricity can do. 1st, It can directly produce _motion_, through the attractions and repulsions of electrified bodies,--as indicated by electrometers, the rotation of the fly-wheel, the deflection of the galvanometer needle. It has been proved by the mathematical labors of Clausius, and confirmed by experiment, that, when electricity performs any mechanical work, so much electricity is lost, annihilated as electricity. 2d, It can directly produce _heat_, as shown by passing a sufficient quantity of electricity through a fine platinum wire: the wire becomes heated, and glows, and it may even be fused by the intensity of the heat. The heat developed in the so-called electric arc is so great as to fuse the most refractory substances. If a current of electricity from a battery be sent through a thermo-pile, one of the faces of the pile will be heated. The heat of the spark from a Leyden jar may be made to ignite gunpowder, and dissipate gold into vapor. The heat produced by lightning is seen when a live tree is struck by a powerful flash: the sap of the tree is instantly converted into steam of so high a tension as to explode the tree, scattering it in small fragments over a wide area. The tips of lightning-rods often exhibit this heating effect, being fused by the passage of too great a quantity of electricity. In the early part of the present century it was demonstrated by Count Rumford, and also by Sir Humphry Davy, that heat was but a form of molecular motion. Since then the exact relations between the motion of a mass of matter and the equivalent heat have been experimentally determined by Joule, so that the unit of heat may be expressed in the motion of a mass of matter. This is deducible from a more general law, known as the conservation of energy. The application in this place is, that whenever heat appears through electric action, as in the above-mentioned places, we know that it still is only _motion_ that is the product, only that this motion is now among the molecules of the body, instead of the motion of the whole body in space, as when a pith-ball moves, or a galvanometer-needle turns. 3d, It can directly produce _light_. This is seen in every spark from an electric machine, in the flash of lightning, and in the electric light. It has been shown in numberless ways, that there is no essential difference between light and heat, and that what we call light is only the active relation which certain rays of radiant energy have to the eyes. In order to make this plain, suppose that a beam of light, say from the sun, be permitted to fall upon a triangular prism of glass: at once it is seen that the beam is deflected, and instead of appearing a spot of white light, as it did before it was deflected, it now appears as a brilliant band of colors, which is called the solar spectrum. If now this spectrum be examined as to the distribution of heat, by moving a thermo-pile through it from the blue end towards the red end, it will be noticed that the galvanometer-needle will be but slightly deflected at the blue end; but, as the thermo-pile is moved, the deflections are greater until it is past the red end, where the heat is greatest. On this account it has been customary to say that the red end of the spectrum was the heating end. With various pieces of mechanism the rays may be separated from each other, and measured; and then it appears that a red ray of light has a wave length of about 1/37000 in., and the violet ray about 1/60000 in. The rays beyond the red have also been measured, and found to be greater in length uniformly as one recedes from the visible part of the spectrum. In like manner, beyond the blue end the wave lengths become shorter and shorter; and in each of these directions the spectrum that is invisible is much longer than the visible one. Now, it has also been found that where a prism of glass or other material is used to produce a spectrum, it distributes the rays very unevenly; that is, towards the red end of the spectrum they are very much crowded, while towards the blue end they are more dispersed. Hence, if one were measuring the heating power of such a spectrum, many more rays would fall upon an equal surface of the thermo-pile at the red end than at the blue end; therefore the indications of the galvanometer would be fallacious. Before any thing definite could be known about the matter, it would plainly be necessary to work with an equal dispersion of all the rays. This was effected a few years ago by Dr. Draper of New York. He took the spectrum produced by diffraction instead of refraction, and measured that. In that way it was found that the heating power of the spectrum is equal in every part of it; and hence the pictures in treatises on physics that represent the heating power of the spectrum to be concentrated at the red end is not true save where the spectrum is irregularly produced. As for vision, the mechanical structure of the eye is such that radiant vibrations having a wave length between 1/37000 in. and 1/60000 in. can affect it, while longer or shorter wave lengths can not. Such waves we call light, but it is not at all improbable that some animals and insects have eyes adapted to either longer or shorter wave-lengths; in which case, what would be perfectly dark to us would be light to them. It is a familiar enough fact, that many animals, such as dogs, cats, rats, and mice, can see in the night. Some horses may be trusted to keep in the road in a dark night, when the driver cannot see even the horse itself. This has usually been accounted for by saying that their eyes are constructed so as to collect a greater number of luminous rays. It is much better explained by supposing their eyes to be constructed to respond to wave-lengths either greater or less than those of mankind. A ray of light, then, consists of a single line of undulations of a definite wave length, such that if it falls upon the eye it will produce sight; if it falls upon a thermo-pile it heats it by just the same quantity that another wave-length would heat it; if it falls upon matter in unstable chemical relations, it will do chemical work, depending upon the kinds of matter. A red ray is as effective for some substances as a violet ray is for others. The statement, then, so often lately made to do certain analogical work, namely, that a ray of light consists of three distinct parts, which may be separated from each other, and are called heat, light, and chemical properties, is simply untrue. What a ray will do, depends upon what kind of a structure it falls on; and when it has done that work, of whatever kind it may be, it ceases to exist as a ray. If, therefore, electricity can directly produce light, it is simply producing _motion_, as in the case of heat, the motion being of such a sort that the eyes of men are affected by it. 4th, It can produce _magnetism_. A current of electricity passing through a coil of wire makes such a coil a magnet, which will set itself in the direction of the magnetic meridian of the earth; and, if a bar of soft iron be placed in the coil, it becomes the familiar electro-magnet; and, if hardened steel be put in it, it becomes a permanent magnet. This leads to the inquiry as to what magnetism is. We know that it can produce motion by its moving at a distance a piece of iron or another magnet. It will also sustain a mass of matter against gravity or some other contrary force. Through such mechanism as magneto-electric machines it produces electricity in great abundance, which again can be used to produce any of the effects of electricity,--moving bodies by attraction or repulsion, generating heat or light, or again making a magnet. But as all of these are but varied forms of motion, either of a mass as a whole, or molecular, can it be doubted for an instant, that what we call magnetism is but some form of motion? Must it not be either some form of matter, or some form of motion? If it were a form of matter, then a magnet would only be permanent so long as it was not used; for use implies consumption of the force; and, if this be matter in any form, then in a given mass of matter there can be but a definite quantity of such magnetic matter, and consumption must lessen that quantity. As a matter of fact, there is no perceptible lessening of the power of a magnet when it is properly used. It is also a matter of fact, that neither motion of a mass, nor electrical effects, nor any other, can be produced by the action of a magnet alone. It is only when some form of motion has been added to its own property, that we get any kind of an effect from it: hence all effects due to its action are _resultants_ of two forces, one of them being common motion of a mass of matter, and the other the energy of the magnet. Hence we infer that a magnet is a mechanism of such a structure as to change the direction and character of the motion which acts upon it. When the wheel of a common electrical machine is turned, the product is electricity,--a force very different from that which originates it. Ordinary mechanical motion _goes in_; electricity _comes out_, the latter being a modified motion due to the physical structure of the machine. In like manner, a magnet may be considered as a machine by means of which mechanical motion may be converted into some other form of motion. It is evident that molecular structure is chiefly concerned in this. If a bar of iron that exhibits no evidence of magnetism whatever be subjected to torsion, it will immediately become a magnet with poles dependent upon the direction of the twist. This developed magnetism will re-act upon a coil of wire, and so move a galvanometer needle. If the bar be permitted to recover its original condition, it will lose its magnetism, which will at once re-appear upon twisting the rod again. Now, when the rod is twisted, it is evident that there is a molecular strain in certain directions throughout the mass. The converse experiment illustrates the same thing. It has been found, that when a rod of iron is made magnetic by the action of a current of electricity circulating about it, and at the same time passing longitudinally through it, the rod is slightly lengthened and twisted in a direction that depends upon the direction of the current. Moreover, if a permanent magnet be heated to a red heat, its magnetism is destroyed; for such a heat allows the molecules to freely arrange themselves without any external constraint. Also, if a permanent magnet be suspended so as to give out a musical sound when it is struck, the magnetism will be much weakened by making it thus to vibrate. In this case, as in the other, the vibrations affect every molecule, and so enable them to re-adjust themselves to the positions they held before being magnetized. The same thing happens when a bar of iron is made magnetic through the inductive action of the earth. When this bar is held in the direction of the magnetic dip, it becomes but very slightly magnetized; but, if it be so held that when it is struck with a hammer it will ring, that is, give out a musical sound, it will at once become decidedly magnetic. Evidently the earth's action tends to set the molecules of the mass in a new position, but cohesion prevents them from assuming it. When the molecules are made to vibrate, they can assume such new positions more readily. The molecules of a magnet, then, are differently arranged from those in an unmagnetized piece of iron or steel; and, for every new arrangement of the molecules of a mass of any kind, we always have some new physical property developed. The same identical substance may appear as charcoal, coke, plumbago, anthracite coal, and diamond. Hence a magnet is a machine in which other forces acting upon it are transformed in character, and re-appear as attractions and repulsions of other kinds of matter: this transformation cannot take place, and hence magnetism cannot become apparent, only upon the condition of another force acting in concert with it; and, if at any time it may seem to be acting without such external force, it is done at the expense of the heat it has absorbed, and therefore the magnet must at such time be losing temperature proportional to the work done. This I have discovered to be true by making a magnet to exert its force in front of a thermo-pile, which uniformly exhibits a cooled face under such conditions. What the particular form of the motion may be that we call magnetism, is not yet made out; but that it is some form of motion, is very evident. The following experiments may throw some light upon it. Last August Mr. Kerr read a paper before the British Association of Science, in which was detailed the following experiment: The pole of an electro-magnet was nicely polished so as to reflect light like a mirror. A beam of sunlight was permitted to fall upon it, and be reflected to a convenient place for examination. A current of electricity was sent through the coil, which of course rendered the iron magnetic; and it was noticed that the light that was reflected from the pole was circularly polarized: that is, the motion of a ray, instead of being a simple undulatory movement, was now made to assume such a motion as the water from a garden-hose has when the nozzle is swung round in a circle while the water is escaping from it. After reading the account of it, it occurred to me that the converse experiment might be tried; that is to say, the effect of a circularly polarized beam of light upon a piece of steel. By concentrating a large beam of ordinary plane polarized light with a quartz lens, and passing it through a quarter wave-plate at the proper angle, a powerful beam of circularly polarized light was obtained. At the focus of this beam a fine cambric needle without magnetism was placed so that the light passed it longitudinally. Ten minutes' exposure was sufficient to make it decidedly magnetic. Hence I infer that the motions which we call magnetic attractions and repulsions may be quite analogous to such helical motions; also, that these motions exist in ether, and evidently may be either right-handed or left-handed. Wind up on a pencil a piece of wire twelve or fifteen inches long, making a loose spiral. Bring the two ends of the spiral together; and note first that one is twisted to the right, the other to the left. If they be twisted into each other, they will advance very easily; but if a right-handed spiral were to be interlocked with another like it, and both turned in the direction of their spiral, they would separate rapidly. Applying this conception to a magnet, we might suppose that such spiral motions will be set up in the ether by the magnet, and that such motions re-acting upon ordinary matter affect it as attraction and repulsion; and thus we should have at least a conceivable mechanical explanation of the phenomenon. [Illustration: FIG. 5.] There are numberless experiments which might be given to further exhibit the relation of mass motion to magnetism, but a single one more must suffice. No rotation of a magnet upon its own axis can produce any effects upon a current that is exterior to it; but if a loop of wire be kept stationary adjacent to a magnet, as in Fig. 5, while the magnet revolves, a current of electricity is produced; and if the magnet be kept stationary, and the loop revolves, a current will also be produced, but in the opposite direction. Here, as in all the other cases, no electricity is originated, save when motion is imparted to one or other of the parts. This experiment is due to Faraday. From all these cases we can come to but one conclusion, that both electricity and magnetism are but forms of motion; electricity being a form of motion in ordinary matter, for it cannot be made to pass through a vacuum, while magnetism must be a form of motion induced in the ether, for it is as effective in a vacuum as out of it; electricity always needing some material conductor, magnetism needing no more than do radiant heat and light. VELOCITY. Measurements have been made of the velocity of electricity; both that of high tension, such as the spark from a Leyden jar, and also that from a battery. The former was found to have a velocity over 200,000 miles a second, while the electricity from a battery may move as slowly as 15,000 or 20,000 miles a second; but this is very largely a matter of conductors. Its velocity is seldom above 30,000 miles a second on ordinary telegraphic lines. If the electricity be used to give signals, as in ordinary telegraphy, the time required varies nearly as the length of the line, and in any case is a much greater quantity. Prescott in his work on the telegraph states that "the time required to produce a signal on the electro-magnet at the extremity of a line of 300 miles of No. 8 iron wire is about .01 seconds, and that this time increases in a greater proportion than the length of the line; for example, on a line 600 miles in length it amounts to about .03 seconds." He also states that it varies much with the kind of magnet used, some forms of magnets being much more sensitive than others for this work. Wheatstone proved a good many years ago that the duration of the electric spark was less than one millionth of a second. When a swiftly moving body can only be seen by an electric spark, or flash of lightning, it looks as if it were quiescent. Thus a train of cars rushing along at the rate of forty or fifty miles per hour appears sharply defined,--even the driving-wheels of the locomotive can be seen in detail, which is impossible in continuous light,--and all seems to be standing still. In like manner will the sails of a windmill, which may be turning at a rapid rate, be seen apparently at rest. This is because in the short time during which they are illuminated they do not appreciably move. I am not aware that any attempt has been made to measure the velocity of magnetism. If, however, it be a form of motion in ether, it is probable that the velocity is comparable to the velocity of radiant energy, light, which is equal to about 186,000 miles a second. SOUND. BEFORE explaining the relation that sound has to telephony, it will be necessary to make quite plain what sound is, and how it affects the substance of the body through which it moves. If I strike my pencil upon the table, I hear a snap that appears to the ear to be simultaneous with the stroke: if, however, I see a man upon a somewhat distant hill strike a tree with an axe, the sound does not reach me until some appreciable time has passed; and it is noted, that, the farther away the place where a so-called sound originates, the longer time does it take to reach any listener. Hence sound has in air a certain velocity which has been very accurately measured, and found to be 1,093 feet per second when the temperature of the air is at the freezing point of water. As the temperature increases, the velocity of sound will increase a little more than one foot for every Fahrenheit degree; so that at 60° the velocity is 1,125 feet per second. This is the velocity in air. In water the velocity is about four times greater, in steel sixteen times, in pine-wood about ten times. CONSTITUTION OF A SINGLE SOUND-WAVE. If a person stands at the distance of fifteen or twenty rods from a cannon that is fired, he will first see the flash, then the cloud of smoke that rushes from the cannon's mouth, then the ground will be felt to tremble, and lastly the sound will reach his ear at the same time that a strong puff of air will be felt. This puff of air is the sound-wave itself, travelling at the rate of eleven hundred feet or more per second. At the instant of explosion of the gunpowder, the air in front of the cannon is very much compressed; and this compression at once begins to move outwards in every direction, so as to be a kind of a spherical shell of air constantly increasing in diameter; and, whenever it reaches an ear, the sound is perceived. Whenever such a sound-wave strikes upon a solid surface, as upon a cliff or a building, it is turned back, and the reflected wave may be heard; in which case we call it an echo. When a cannon is fired, we generally hear the sound repeated, so that it apparently lasts for a second or more; but when, as in the first case, we hear the sound of a pencil struck upon the table, but a single short report is noticed, and this, as may be supposed, consists of a single wave of condensed air. [Illustration: FIG. 6.] [Illustration: FIG. 7.] Imagine a tuning-fork that is made to vibrate. Each of the prongs beats the air in opposite directions at the same time. Look at the physical condition of the air in front of one of these prongs. As the latter strikes outwards, the air in front of it will be driven outwards, condensed; and, on account of the elasticity of the air, the condensation will at once start to travel outwards in every direction,--a wave of denser air; but directly the prong recedes, beating the air back in the contrary direction, which will obviously rarefy the air on the first side. But the disturbance we call rarefaction moves in air with the same velocity as a condensation. We must therefore remember, that just behind the wave of condensation is the wave of rarefaction, both travelling with the same velocity, and therefore always maintaining the same relative position to each other. Now, the fork vibrates a great many times in a second, and will consequently generate as many of these waves, all of them constituted alike, and having the same length; by length meaning the sum of the thicknesses of the condensation and the rarefaction. Suppose a fork to make one hundred vibrations per second: at the end of the second, the wave generated by the vibration at the beginning of the second would have travelled, say, eleven hundred feet; and evenly distributed between the fork and the outer limit, would be ranged the intermediate waves occupying the whole distance: that is to say, in eleven hundred feet there would be one hundred sound-waves, each of them evidently being eleven feet long. If the fork made eleven hundred vibrations per second, each of these waves would be one foot long; for sound-waves of all lengths travel in air with the same rapidity. Some late experiments seem to show that the actual amplitude of motion of the air, when moved by such a high sound as that from a small whistle, is less than the millionth of an inch. PITCH. The pitch of a sound depends wholly upon the number of vibrations per second that produce it; and if one of two sounds consists of twice as many vibrations per second as the other one, they differ in pitch by the interval called in music an octave, this latter term merely signifying the number of intervals into which the larger interval is divided for the ordinary musical scale. The difference between a high and a low sound is simply in the number of vibrations of the air reaching the ear in a given time. The smaller intervals into which the octave is divided stand in mathematical relations to each other when they are properly produced, and are represented by the following fractions:-- C D E F G A B C 1 9/8 5/4 4/3 3/2 5/3 15/8 2 [Illustration] These numbers are to be interpreted thus: Suppose that we have a tuning-fork giving 256 vibrations per second: the sound will be that of the standard or concert pitch for the C on the added line as shown on the staff. Now, D when properly tuned will make 9 vibrations while C makes but 8; but, as C in this case makes 256, D must make 256×9/8=288. In like manner G is produced by 256×3/2=384, and C above by 256×2=512, and so on for any of the others. If other sounds are used in the octave above or below this one, the number of vibrations of any given note may be found by either doubling or halving the number for the corresponding note in the given octave. Thus G below will consist of 384/2=192, and G above of 384×2=768. During the past century there has been a quite steady rise in the standard pitch, and this has been brought about in a very curious and unsuspected way. The tuning-fork has been the instrument to preserve the pitch, as it is the best available instrument for such a purpose, it being convenient to use, and does not vary as most other musical instruments do. But a tuning-fork is brought to its pitch with a file, which warms it somewhat, so that at the moment when it is in tune with the standard that is being duplicated it is above its normal temperature; and when it cools its tone rises. When another is made of like pitch with this one, the same thing is repeated; and so it has continued until the standard pitch has risen nearly a tone higher than it was in Händel's time. The common A and C tuning-forks to be had in music stores, often vary a great deal from the accepted concert pitch. Such as the writer has measured have been generally too high; sometimes being ten or more vibrations per second beyond the proper number. The tuning-forks made by M. Köenig of Paris are accurate within the tenth of one vibration, the C making 256 vibrations in one second. LIMITS OF AUDIBILITY. Numerous experiments have been made to determine the limits of audible sounds; and here it is found that there is a very great difference in individuals in their ability to perceive sounds. Helmholtz states that about 23 vibrations per second is the fewest in number that can be heard as continuous sound; if they are fewer in number than that, the vibrations are heard as separate distinct noises, as when one knocks upon a door four or five times a second. If one could knock evenly 23 times per second, he would be making a continuous musical sound of a very low pitch. But this limit of 23 is not the limit for all: some can hear a continuous sound with as few as 16 or 18 vibrations per second, while others are as far above the medium as this is below it. The limits of sound in musical instruments are about all included in the range of a 7-octave pianoforte from F to F, say from 42 to 5,460 vibrations per second. But this high number is not anywhere near the upper limit of audible sounds for man. Very many of the familiar sounds of insects, such as crickets and mosquitoes, have a much higher pitch. Helmholtz puts this upper limit at 38,000 vibrations per second, and Despraetz at 36,850. The discrepancy of results is due solely to the marked difference in individuals as to acoustic perception. For the production of high musical tones, Köenig of Paris makes a set of steel rods. A steel rod of a certain length, diameter, and temper, will give a musical sound which may be determined. The proper length for other rods for giving higher tones may be determined by the rule that the number of vibrations is inversely proportional to the square of the length of the rod. The dimensions of these rods when made 2 c. m. in diameter are as follows:-- Length. Vibrations. 66.2 m. m. 20,000 59.1 " " 25,000 53.8 " " 30,000 50.1 " " 35,000 47.5 " " 40,000 These rods need to be suspended upon loops of silk, and they are struck with a piece of steel so short as to be wholly beyond the ability of any ear to hear its ring. Nothing but a short thud is to be heard from it when it strikes, while from the others comes a distinct ringing sound. In experimenting with such a set of steel rods I have not found any one yet who could hear as many as 25,000 per second, my own limit being about 21,000. But it has been experimentally found that children and youth have a perceptive power for high sounds considerably above adults. Dr. Clarence Blake of Boston reports a case in his aural practice, of a woman whose hearing had been gradually diminishing for some years until she could not hear at all with one ear, and the ticking of a watch could only be heard with the other when the watch was held against the ear. After treatment it was discovered that the sensibility to high sounds was very great, and that she could hear the steel rod having a tone of 40,000 vibrations. Last year Mr. F. Galton, F.R.S., exhibited before the Science Conference an instrument in the shape of a very small whistle, which he had devised for producing a very high sound. The whistle had a diameter less than the one twenty-fifth of an inch. The length could be varied by moving a plug at the end of the whistle. It was easy to make a sound upon such an instrument that was altogether out of hearing-range of any person. Mr. Galton tried some very interesting experiments upon animals, by using these whistles. He went through the Zoölogical Gardens, and produced such high sounds near the ears of all the animals. Some of them would prick up their ears, showing that they heard the sound; while others apparently could not hear it. He declares that among all the animals the cat was found to hear the sharpest sound. Small dogs can also hear very shrill notes, while larger ones can not. Cattle were found to hear higher sounds than horses. The squeak of bats and of mice cannot be heard by many persons who can hear ordinary sounds as well as any; sharpness of hearing having nothing to do with the limits of hearing. EFFECTS OF SOUND UPON OTHER BODIES. If a vibrating tuning-fork be held close to a delicately suspended body, the latter will approach the fork, as if impelled by some attractive force. The experiment can be made by fastening a bit of paper about an inch square to a straw five or six inches long, and then suspending the straw to a thread, so that it is balanced horizontally. Bring the vibrating tuning-fork within a quarter of an inch of the paper. In this case the motion of approach is due to the fact that the pressure of the air is less close to a vibrating body than at a distance from it; there is therefore a slightly greater pressure on the side of the paper away from the fork than on the side next to it. If a vibrating tuning-fork be held near to the ear, and turned around, there may be found four places in one rotation where the sound will be heard but very faintly, while in every other position it can be heard plainly enough. The extinction of the sound is due to what is called interference. Each of the prongs of the fork is giving out a sound-wave at the same time, but in opposite directions, each wave advancing outwards in every direction. Where the rarefied part of one wave exactly balances the condensed part of the other, there of course the sound will be extinguished; and these lines of interference are found to be hyperbolas, or, if considered with reference to both entire waves, two hyperbolic surfaces. SYMPATHETIC VIBRATIONS. When it is once understood that a musical sound is caused by the vibrations more or less frequent which only make the difference we call pitch, it might at once be inferred, that if we have a body that is capable of vibrating say a hundred times a second, and it receives a hundred pulses or pushes a second, it would in this way be made to vibrate. Suppose, then, that we take two tuning-forks, each capable of vibrating 256 times a second: if one be struck while the other is left free, the former one will be giving to the air 256 impulses per second, which will reach the other fork, each pulse tending to move it a little, the cumulative result being to make it move perceptibly, that is, to give out a sound. The principle is just the same as that employed in the common swing. One push makes the swing to move a little, upon its return another is given, in like manner a third, and so on until a person may be swung many feet high. If a glass tumbler be struck, it gives out a musical sound of a certain pitch, which will set a piano-string sounding that is tuned to the same pitch, provided that the damper be raised. It is said that some persons' voices have broken tumblers by singing powerfully near them the same note which the tumblers could give out, the vibrations of the tumblers being so great as to overcome cohesion of the molecules. There are very many interesting effects due to sympathetic vibrations. Large trees are sometimes uprooted by wind that comes in gusts timed to the rate of vibration of the tree. When troops of soldiers are to cross a bridge, the music ceases, and the ranks are broken, lest the accumulated strain of timed vibrations should break the structure; indeed, such accidents have several times occurred. There is not so much danger to a bridge when it is heavily loaded with men or with cattle, as when a few men go marching over it. "When the iron bridge at Colebrooke Dale was building, a fiddler came along, and said to the workmen that he could fiddle their bridge down. The builders thought this boast a fiddle-de-dee, and invited the musician to fiddle away to his heart's content. One note after another was struck upon the strings, until one was found with which the bridge was in sympathy. When the bridge began to shake violently, the workmen were alarmed at the unexpected result, and ordered the fiddler to stop." Some halls and churches are wretchedly adapted to hear either speaking or singing in. If wires be stretched across such halls, between the speaker's stand and the opposite end, they will absorb the passing sound-waves, and will be made to sympathetically vibrate, thus preventing in a good degree the interfering echoes. The wire should be rather fine piano-wire, and it should be stretched so tightly as to give out a low musical sound when plucked with the fingers. In a large hall there should be twenty or more such wires. RESONANCE. When a tuning-fork is struck, and held out in the air, the vibrations can be felt for a time by the fingers; but the sound is hardly audible unless the fork be placed close to the ear. Let the stem of the fork rest upon the table, a chair, or any solid body of considerable size, and the sound is so much increased in loudness as to be heard in every part of a large room. The reason appears to be, that in the first case the vibrations are so slight that the air is not much affected. Most of the force of the vibration is absorbed by the hand that holds it; but when the stem rests upon a hard body of considerable extent, the vibrations are given up to it, and every part of its surface is giving off the vibrations to the air. In other words, it is a much larger body that is now vibrating, and consequently the air is receiving the amplified sound-waves. If the stem of the fork had been made to rest upon a bit of rubber, the sound would not only not have been re-enforced in such a way, but the fork would very soon have been brought to rest; for India rubber _absorbs_ sound vibrations, and converts them into heat vibrations, as is proved by placing such a combination upon the face of a thermo-pile. If one will but put his hand upon a table or a chair-back in any room where a piano or an organ is being played, or where voices are singing, especially in church, he cannot fail to feel the sound; and if he notices carefully he will perceive that some sounds make such table or seat to shake much more vigorously than others,--a genuine case of sympathetic vibrations. It is for this reason that special materials and shapes are given to parts of musical instruments, so that they may respond to the various vibrations of the strings or reeds. For instance, the piano has an extensive thin board of spruce underneath all the strings, which is called the sounding-board. This board takes up the vibrations of the strings; but, unlike the rubber, gives them all out to the air, greatly re-enforcing their strength, and changing somewhat their quality. But the air itself may act in like manner. In almost any room or hall not more than fifteen or twenty feet long, a person can find some tone of the voice that will seem to meet some response from the room. Some short tunnels will from certain positions yield very powerful, responsive, resonant tones. There is certainly one such in Central Park, New York. It is forty or fifty feet long. To a person standing in the middle of this, and speaking or making any kind of a noise on a certain pitch, the resonance is almost deafening. It is easy to understand. When a column of air enclosed in a tube is made to vibrate by any sound whose wave-length is twice the length of the tube, we have such column of air now filled with the condensed part of the wave, and now with the rarefied part; and as these motions cannot be conducted laterally, but must move in the direction of the length of the tube, the air has a very great amplitude of motion, and the sound is very loud. If one end of the tube be closed, then the length must be but one-fourth of the wave-length of the sound. Take a tuning-fork of any convenient pitch, say a C of 512 vibrations per second: hold it while vibrating over a vertical test-tube about eight inches long. No response will be heard; but, if a little water be carefully poured into the tube to the depth of about two inches, the tube will respond loudly, so that it might be heard over a large hall. In this case the length of the air-column that was responding, being one-fourth the wave-length, would give twenty-four inches as the wave-length of that fork. It is easy in this way to measure approximately the number of vibrations made by a fork. Letting _l_ = depth of tube, _d_ = diameter of tube, _v_ = velocity of sound reduced for temperature, _N_ = number of vibrations, Then _N_ = _v_ ------------ (4(_l_+_d_)). When a vibrating tuning-fork is placed opposite the embouchure of an organ-pipe of the same pitch, the pipe will resound to it, giving quite a volume of sound. In 1872 it occurred to me, that the action of an organ-pipe might be quite like that of a vibrating reed in front of the embouchure. As the air is driven past it from the bellows, the form of the escaping air will evidently be like a thin, elastic strip; and, having considerable velocity, it will carry off by friction a little of the air in the tube: this will of course rarefy the air in the tube somewhat, and a wave of condensation will travel down the tube. At the bottom, being suddenly stopped, its re-action will be partly outwards, and so will drive the strip of air away from the tube. After this will follow, for a like reason, the other phase of the wave, the rarefaction, which will swing the strip of air towards the tube. This theory I verified by filling the bellows with smoke, and watching the motion of the escaping air and smoke with a stroboscope. This view is now advocated by an organ-builder in England, Herman Smith; but whether he discovered it before or after me, I do not know. When a membrane vibrates, its motion is generally perceptible to the eye; and it may have a very great amplitude of motion, as in the case of the drum; and various instruments have been devised for the study of vibrations, using membranes like rubber, gold-beater's skin, or even tissue paper, to receive the vibrations. One of the musical instruments of a former generation of boys was the comb. A strip of paper was placed in front of it, and placed at the mouth, and sung through, the paper responding to the pitch with a loose nasal sound. Köenig fixed a membrane across a small capsule, one side of which was connected by a tube to any source of sound, and the other side to a gas-pipe and a small burner. A sound made in the tube would shake the flame, and a mirror moving in front of the flame would show a zigzag outline corresponding to the sound vibrations. In like manner if a thin rubber be stretched over the end of a tube one or two inches in diameter and four or five inches long, and a bit of looking-glass one-fourth of an inch square be made fast to the middle of the membrane, the motions of the latter can be seen by letting a beam of sunlight fall upon the mirror so as to be reflected upon a white wall or screen a few feet away. (Fig. 8.) [Illustration: FIG. 8.] When a sound is made in this tube, the spot of light will at once assume some peculiar form,--either a straight line with some knots of light in it, or some curve simple or compound, and such as are known as Lissajous curves. If, while some of these forms are upon the screen, the instrument be moved sideways, the forms will change to undulating lines with or without loops, varying with the pitch and intensity, but being alike for the same pitch and intensity. (Fig. 9) This instrument I called the opeidoscope. [Illustration: FIG. 9.] The vibration of a membrane and that of a solid differ chiefly in the amplitude of such vibration. The scratch of a pin at one end of a long log can be heard by an ear applied to the other end of the log; but every molecule in the log must move slightly; and there are all degrees of movement between that visible to the eye, which we call mass motion, and that called molecular simply because we cannot measure the amplitude of the motion. We may, then, roughly divide all bodies into two classes, as to their relations to sound,--such as re-enforce it, and such as distribute it: the first depending upon the form of the body, as related to a particular sound; the second independent of form, and responding to all orders of vibrations. Air, wood, and metals belong in this latter class. The common toy-string telegraph, or _lovers' telegraph_, is an example of this class. Two tin boxes are connected by a string passing through the middle of the bottom of each. When the string is stretched, and a person speaks in one box, what is said can be heard by an ear applied at the other. If the speaking-tubes be made about four inches in diameter, and about four inches deep, they are capable of doing much more service than is generally supposed to be possible. I know of two lines, one of five hundred feet and the other of a thousand feet in length, over which one can talk, and be heard with distinctness. In the line of a thousand feet, the end of the tube is made of sheepskin tightly stretched, and the line is made of No. 8 cotton thread. The greater the tension, the better is the sound transmitted. The thread is supported at intervals by running through a loop on the ends of cords not less than three feet long, attached to supports. The thread pierces the membrane, and is attached to a small button which is in contact with the membrane. Wind and rain affect this line disadvantageously. The other line of five hundred feet, between a passenger and a freight depot, has the tube end covered with stretched calfskin. Instead of thread, a copper-relay wire is employed (any small uninsulated wire will do as well). This permits a good tension, and is unaffected by the weather. One may stand in front of it about three feet, and converse with ease, and in an ordinary tone. The wire is supported in loops of string, as in the other. Musicians have in all times employed various instruments for the production of musical effects. Whistles made of bone were used by pre-historic men, some of them having finger-holes so that different tones could be produced. A stag-horn that was blown like a flageolet, and having three finger-holes, has also been found; while on the old monuments of Egypt are pictured harps, pipes with seven finger-holes, a kind of flute, drums, tambourines, cymbals, and trumpets. In later times these primeval forms have been modified into the various instruments in use in the modern orchestra. It seems as if no musician had ever been interested in the question as to why one instrument should give out a sound so different from another one, even though it was sounding upon the same pitch. No one can ever mistake the sound of a violin, or a horn, or a piano, for any other instrument; and no two persons have voices alike. This difference in tone, which enables us to identify an instrument by its sound or a friend by his voice, is called quality of tone, or _timbre_. About twenty years ago, that great German physicist Helmholtz undertook the investigation of this subject, and succeeded in unravelling the whole mystery of the qualities of sound. He discovered first, that a musical sound is very rarely a simple tone, but is made up of several tones, sometimes as many as ten or fifteen, having different degrees of intensity and pitch. The lowest sound, which is also the strongest, is called the _fundamental_; and it is this tone we mean when we speak of the pitch of a sound, as the pitch of middle C upon a piano, or the pitch of the _A_ string on a violin. The higher sounds that accompany the fundamental are called sometimes harmonics, sometimes upper partial tones, but generally _overtones_. The character or quality of a sound depends altogether upon the number and intensity of these overtones associated with the fundamental. If a sound can be made upon a pipe and a violin, that consists wholly of the fundamental with no overtones, the two instruments sound absolutely alike. It is exceedingly difficult to do this; and such sound when produced is smooth, but without character, and unpleasing. Second, Helmholtz discovered that the overtones always stand in the simplest mathematical relation to the fundamental tone,--in fact, are simple multiples of that tone, being two, three, four, and so on, times the number of vibrations of it. This will be readily understood by considering the position of such related sounds when they are written upon the staff. [Illustration] If we start with C in the bass as indicated in the staff, calling that the fundamental, then the notes that will represent the above ratios are those indicated by smaller notes, which are the overtones up to the ninth. The first overtone, being produced by twice the number of vibrations, must be the octave; the second, the fifth of the second octave; the third will be two octaves from the first, and so on: the number of vibrations of each of these notes being the number of the fundamental multiplied by its order in the series. Taking C with 128 vibrations, we have for this series:-- 128 × 1 = 128 = C fundamental. 128 × 2 = 256 = C´. 128 × 3 = 384 = G´. 128 × 4 = 512 = C´´. 128 × 5 = 640 = E´´. 128 × 6 = 768 = G´´. 128 × 7 = 896 = B´´[flat]. 128 × 8 = 1,024 = C´´´. 128 × 9 = 1,152 = D´´´. 128 × 10 = 1,280 = E´´´. This series is continued up to the limits of hearing. Now, it appears that all instruments do not give the complete series: indeed, it is not possible to obtain them all upon some instruments. Each of them, however, when present helps in the general effect which we call quality. Sometimes the overtones are more prominent than the fundamental, as when a piano-wire is struck with a nail. It has always been noticed that it does not give out the sound that is wanted when it is struck in this way. Hence it is the art of an instrument-maker to so construct the instrument as to develop and re-enforce such tones as are pleasing, and to suppress the interfering and disagreeable overtones. Piano-makers learned by trial where was the proper place to strike the stretched wire in order to develop the most musical sound upon it; but no reason could be given until it was observed that striking it at a point about one-seventh or one-ninth its length from either end prevented the development of the objectionable overtones, the seventh and the ninth. Hence they can scarcely be heard in a properly constructed instrument. These overtones are very discordant with the lower sounds. Organ-pipes have their specific qualities given to them by making them wide-mouthed, narrow-mouthed, conical, and so on; shapes which experience has determined give pleasing sounds with different qualities. The violin is an instrument that seems to puzzle makers more than almost any other. Some of the old violins made two hundred years ago by the Amati family at Cremona are worth many times their weight in gold. Recent makers have tried in vain to equal them; but, when their ingenuity and skill have failed, they declare that _age_ has much to do with such instruments, that age mellows the sounding quality of the violin. But the Cremona violins were just as extraordinary instruments when they left the hands of the makers as they are now; and the fame of the Amati family as violin-makers was over all Europe while they were living. A good violin when well played gives an exquisite musical effect, and on account of its range and quality of tones it is the leading orchestral instrument, always pleasing and satisfying; but in unskilled hands even the best _Cremona_ will give forth sounds that make one grieve that it was ever invented. Overtones of all sorts and with all degrees of prominence may be easily developed upon it: therefore the skilful player draws the bow at such a place upon the strings as to develop the overtones he wants, and suppress the ones not wanted. The usual rule is to draw the bow about an inch below the bridge; but the place for the bow depends upon where the fingers are that stop the strings, and also the pressure upon it. It requires an almost incredible amount of practice to be able to play a violin very well. In the accompanying table will be found the component parts of tones upon a few instruments in common use. TONE COMPOSITION. The components of the tones are indicated by lines in the column underneath the figures representing the series. Thus the narrow-stopped organ-pipe gives a sound composed of a fundamental, and overtones three, five, seven, and nine times the number of vibrations of it. TONE COMPOSITION. --------------------------+---+---+---+---+---+---+---+---+---+--- INSTRUMENTS. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 --------------------------+---+---+---+---+---+---+---+---+---+--- / Wide stopped | / | | | | | | | | | | +---+---+---+---+---+---+---+---+---+--- | Narrow " | / | | / | | / | | / | | / | | +---+---+---+---+---+---+---+---+---+--- | Narrow cylinder | / | / | / | / | / | / | | | | ORGAN < +---+---+---+---+---+---+---+---+---+--- PIPES. | Principal }| / | / | / | | | | | | | | (Wood) }| | | | | | | | | | | +---+---+---+---+---+---+---+---+---+--- | Conically }| / | | | | / | / | / | | | \ narrow at top. }| | | | | | | | | | +---+---+---+---+---+---+---+---+---+--- Flute | / | / | / | / | | | | | | +---+---+---+---+---+---+---+---+---+--- Violin | / | / | / | / | / | / | / | / | / | / +---+---+---+---+---+---+---+---+---+--- Piano | / | / | / | / | / | / | / | / | | +---+---+---+---+---+---+---+---+---+--- Bell | / | / | / | / | / | / | / | | | +---+---+---+---+---+---+---+---+---+--- Clarionet | / | | / | | / | | / | | / | +---+---+---+---+---+---+---+---+---+--- Bassoon | / | / | / | / | / | / | / | | | +---+---+---+---+---+---+---+---+---+--- Oboe | / | / | / | / | / | / | / | | | --------------------------+---+---+---+---+---+---+---+---+---+--- It must not be inferred that all of the overtones are of equal strength: they are very far from that; but these differ in different instruments, and it is this that constitutes the difference between a good instrument and a poor one of the same name. In a few of the spaces very light lines are made for the purpose of indicating that such overtones are quite weak. For instance: the piano has the sixth, seventh, and eighth thus marked; these tones being suppressed by the mechanism, as described on a former page. Only a few of the many forms of organ-pipes are given; but these are sufficient to show what a physical difference there is between the musical tones in such pipes. As for the human voice, it is very rich in overtones; but no two voices are alike, therefore it would be impossible to tabulate the components of it in the manner they are tabulated for musical instruments. In Helmholtz's experiments in the analysis of sounds, use was made of the principle of resonance of a body of air enclosed in a vessel. In the experiment with the tuning-fork to determine the wave-length, p. 78, it is remarked that no response came until the volume of the air in the tube was reduced to a certain length, which depended upon the vibration number of the fork. If instead of a test-tube a bottle had been taken, the result would have been the same. Every kind of a vessel can respond to some tone of a definite wave-length, and a sphere has been found to give the best results. These are made with a hole on one side for the sound-wave to enter, and a projection on the opposite side, through which a hole about the one-eighth of an inch is made, this to be placed in the ear. Any sound that is made in front of the large orifice will not meet any response, unless it be that particular one which the globe can naturally re-enforce, when it will be plainly heard. Suppose, then, one has a series of twenty or more of these, graduated to the proper size for re-enforcing sounds in the ratio of one, two, three, four, and so on. Take any instrument, say a flute: have one to blow it upon the proper pitch to respond to the largest sphere, then take each of the spheres in their order, applying them to the ear while the flute is being sounded. When the overtones are present they will be heard plainly and distinct from the fundamental sound. In like manner any or all other sounds may be studied. But Helmholtz did not stop after analyzing sounds of so many kinds: he invented a method of synthesis, by which the sounds of any kind of an instrument could be imitated. A tuning-fork, when made to vibrate by an electric current, gives out a tone without harmonics or overtones. So if a series of forks with vibration periods equal to the numbers of the series of overtones given on p. 86 be so arranged that any of them may be made to vibrate at will, it is evident that the resulting compound tone would be comparable with that from an instrument having such overtones. Thus, if with a tuning-fork giving a fundamental C, other forks giving two, three, and four times the number of the fundamental were associated, each one giving a simple tone, we should have for a resultant the tone of a flute, as shown on p. 91. If one, three, five, seven, and nine, were all sounded, the resulting tone would be that of the clarionet, and so on. This he actually accomplished, and now makers of physical apparatus advertise just such instruments. Helmholtz also contrived a set of tuning-forks, which, when bowed, will give out the vowel sounds like the voice. It was remarked upon p. 89 that it has generally been considered that age has a mellowing effect upon the sound of a violin. Once in possession of the facts concerning sound that have been alluded to on the preceding pages, it is easy to see how such an opinion should arise, and also the fallacy of it. It is proved conclusively that the ability to hear high sounds decreases as one grows older. As the violin gives a very great number of overtones, even up to the limits of audibility, it is plain that if such an instrument should not change in its quality of tone in the least degree, yet to a man who played upon it for a number of years it would seem to change by subtracting some of the higher overtones from the sound; that is, it would seem to become mellower. There is no evidence that such a physical change takes place in the instrument. It is not here affirmed that no change does take place. It may be probable; but all the evidence we have is the opinions of individuals whose hearing we know does change; and this change is competent to modify the judgment as to the quality of the sound in the same direction. Before it can be affirmed that such a physical change does take place in the violin as to make a perceptible difference in the quality of its tone, it will be needful to determine accurately the number and intensity of the overtones at intervals during many years, and then to compare them. This has not yet been done. FORM OF A COMPOUND SOUND-WAVE IN AIR. Upon p. 63 is given a picture of the form of a simple sound-wave in air, which, as described, consists of two parts, a condensation and a rarefaction. All simple sound-waves have such a form; but when two or more sound-waves that stand in some simple ratio to each other, as do the sounds of musical instruments, are formed in air, the resulting wave is more or less complex in structure; and where there are many components, as there are where a number of different kinds of instruments are all sounding at once, it is well-nigh impossible to figure even approximately the form of such wave-combinations. It is generally given in treatises upon sound with ordinates representing the factors with their relative intensities. When the extremities of the ordinates are connected, there is drawn a curved line with regularly recurring loops. This cannot give a correct idea of the form of the wave, because the motion of a particle of air is not up and down like a floating body upon waving water, but it is forward and back, in the direction of the motion of the wave. In Fig. 10 three simple sound-waves are thus represented at 1, 2, and 3, these having the wave-length 1, 2, and 3. In 4, the three are combined into one compound wave, and better show the form of a transverse section of such a sound-wave in the air. The organ-pipe called the principal gives out such a compound wave as is seen by referring to the table on p. 91. The second overtone, however, is quite weak in that pipe, which would so modify the form as to lessen somewhat the density at _b_, and increase it at _a_. [Illustration: FIG. 10.] In like manner the space in the length of the fundamental sound, whatever it may be, is divided up into a number of minor condensations and rarefactions, which may strengthen each other, or so interfere as to change the position of both; as is seen in the figure at _b_, where the condensation due to wave 2 interferes with the rarefaction of 3. CORRELATION. HAVING treated at some length of the three factors involved in telephony,--namely, electricity, magnetism, and sound,--it remains to follow up the various steps that have led to the actual transmission of musical sounds and speech over an ordinary electric circuit. It is stated upon p. 31, that, when a current of electricity is passed through a coil of wire that surrounds a rod of soft iron, the latter is made a temporary magnet: it loses its magnetic property the instant that the current ceases. If the rod be of considerable size, say a foot or more in length, and half an inch or more in diameter, and the current be strong enough to make a powerful magnet of it, whenever the current from the battery is broken, the bar may be heard to give out a single _click_. This will happen as often as the current is broken. This is occasioned by a molecular movement which results in a _change_ of _length_ of the bar. When it is made a magnet, it elongates about 1/25000 of its length; and, when it loses its magnetism, it _suddenly_ regains its original length; and this change is accompanied with the sound. This sound was first noticed by Prof. C. G. Page of Salem, Mass., in 1837. If some means be devised for breaking such a circuit more than fifteen or sixteen times a second, we shall have a continuous sound with a pitch depending upon the number of clicks per second. Such a device was first invented by the same man, and was accomplished by fixing the armature of an electro-magnet to a spring which was in the circuit when the spring was pressing against a metallic knob, at which time the current made the circuit in the coil of the electro-magnet. The magnet attracting the armature away from the button broke the circuit, which of course destroyed the magnetism of the magnet, and allowed the spring to fly back against the button, to complete the circuit and reproduce the same series of changes. The rapidity with which the current may be broken in this way is only limited by the strength of both spring and current. The greater the tension of the spring with a given current, the greater number of vibrations will it make. [Illustration: FIG. 11.] Suppose such an intermittent current to pass through the coil surrounding the soft iron rod, 256 times per second; then the rod would evidently give 256 clicks per second, which would have the pitch of C. When these clicks are produced in the rod hold in the hand, the sound is hardly perceptible, being like that of a sounding tuning-fork when held thus. In order to strengthen it, it is necessary to place it on some resonant surface. It is customary to mount it upon an oblong box with one or two holes in its upper surface, inasmuch as such a form is found to give a louder response than any other, and is the shape usually given to Æolian harps. The accompanying cut shows the combination of battery B, the circuit-breaker, and the rod mounted upon the box. The wire W may evidently be of any length, the magnetized rod and box responding to the number of vibrations of the spring S, how long soever the circuit may be. HELMHOLTZ' ELECTRIC INTERRUPTOR. In some of Helmholtz' experiments, it was essential to maintain the vibrations of a tuning-fork for a considerable time. He effected this by placing a short electro-magnet between the prongs of the fork, and affixing a platinum point at the end of one prong in such a manner, that, as the prong descended in its vibration, the platinum point dipped into a small cup of mercury that completed the circuit. When the prong receded, it was of course withdrawn from the mercury, and the current was broken. As it is not possible for a tuning-fork to vibrate in more than one period, such an arrangement would evidently make and break the current as many times per second as the fork vibrated. When, therefore, such an interruptor is inserted in the circuit with the click-rod on its resonant box, the latter must give out just such a sound as the fork is giving. With such a device, it is possible to reproduce at almost any distance in a telegraphic circuit, a sound of a given pitch. It is therefore a true telephone. REISS' TELEPHONE. The ease with which membranes are thrown into vibrations corresponding in period to that of the sounding body has already been alluded to on p. 80; and several attempts have been made, at different times, to make membranes available in telephony. The first of these attempts was made by Philip Reiss of Friedrichsdorf, Germany, in 1861. His apparatus consisted of a hollow box, with two apertures: one in front, in which was inserted a short tube for producing the sound in, and indicated by the arrow in the cut, Fig. 12; the other on the top. This was covered with the membrane _m_,--a piece of bladder stretched tight over it. Upon the middle of the membrane, a thin piece of platinum was glued; and this piece of platinum was connected by a wire to a screw-cup from which another wire went to a battery. [Illustration: FIG. 12.] A platinum finger, S, rested upon the strip of platinum, but was made fast at one end to the screw-cup that connected with the other wire from the battery. Now, when a sound is made in the box, the membrane is made to vibrate powerfully: this makes the platinum strip to strike as often upon the platinum finger, and as often to bound away from it, thus making and breaking the current the same number of times per second. If, then, a person sings into this box while it is in circuit with the afore-mentioned click-rod and box, the latter will evidently change its pitch as often as it is changed by the voice. In this apparatus we have a telephone with which a melody may be reproduced at a distance with distinctness. But the sounds are not loud, and they have a tin-trumpet quality. If one reflects upon the possibilities of such a mechanism, and upon the conditions necessary to produce a sound of any given quality, as that of the voice or of a musical instrument as described in preceding pages, he will understand that it can reproduce only pitch. It might here be inferred that something more than a single pitch is transmitted if the sound is like that of a tin trumpet as stated: but the reason of this is that, whenever a current is passing between two surfaces that can move only slightly on each other, there is always an irregularity in the conduction, so as to produce a kind of scratching sound; and it is this, combined with the other, the true pitch, that gives the character to the sound of this instrument. Dr. Wright found that a sound of considerable intensity could be obtained by passing the interrupted current through the primary wire of a small induction coil, and placing a conductor made of two sheets of silvered paper placed back to back in the secondary circuit. The silvered paper becomes rapidly charged and discharged, making a sound that can be heard over a large hall, and having the same pitch as the sending instrument. GRAY'S TELEPHONES. In 1873 Mr. Elisha Gray of Chicago discovered that if an induction coil be made to operate by the current from any automatic circuit-breaker, and one of the wires from the secondary circuit be held in the hand while the dry finger of the same hand is rubbed upon a sonorous metallic plate, the other wire being in connection with the plate, a musical sound would be given out by the plate, appearing to come from the point of contact of the finger with the plate. He therefore contrived a musical instrument with a range of two octaves, in which the reeds were made to vibrate by electro magnets, the current entering any one by depressing the appropriate key. This circuit is sent through the primary wire of an induction coil while one of the terminals of the secondary coil is connected with the thin sheet metal that forms one head of a shallow wooden drum about eight inches in diameter, which is so fixed as to be rotated like a pulley. The other terminal is held in the hand while one finger of the same hand rests upon the metallic surface. While the drum is turned with the other hand, the sounds given out have considerable intensity. The faster the drum is turned, the louder do the sounds become, though the pitch remains the same. In this case, as in the case mentioned on p. 105, we have an electric current passing between two surfaces that are moving upon each other; the contact not being uniform, the current is varying as well as intermittent. Mr. Gray has also invented a musical telephone by means of which many musical sounds may be simultaneously transmitted and reproduced. The actual mechanism used is quite complex, and requires considerable familiarity with electrical science in order to understand it; but the fundamental principle involved is not difficult to one who has comprehended the preceding descriptions. Suppose that we have a series of four steel reeds, each one fixed at one end to one pole of a short electro-magnet, while the other end is left free to vibrate over the other pole of the magnet and not quite touching it. Each of the reeds is to be tuned to a different pitch, say the 1, 3, 5, and 8 of the scale. These electro-magnets with their attached vibrators are to be attached each to a resonant box (see p. 93), which can respond to that particular number of vibrations per second. This is the receiving instrument. The sender consists of a like set of reeds tuned to the same pitch, which can be made to vibrate at will by pressing a key which sends the current of electricity through its electro-magnet, which makes and breaks the current. Imagine one of these keys to be pressed down so as to make the circuit complete: the sending instrument then has one of its reeds, let it be the 1 of the scale, set in vibration; the intermittent current traverses the whole line, going through all four of the receiving instruments. Now, we know from the study of the action of sounding bodies, that only one of the four receivers is competent to vibrate in consonance with this tone, and this one will respond; that is, the vibrations are truly sympathetic vibrations. If, instead of making the 1 of the scale in the sending-instrument, the 3 had been made, the current would have gone through all of the receiving instruments just the same as before, but only one of them could take up that vibratory movement: three of them would remain at rest, the 3 responding loudly. In like manner, any number of vibrating reeds in the sending instrument can make a corresponding number of reeds in the receiving instrument to vibrate, provided the latter be exactly tuned with the former. Each transmitter is connected with but a part of the battery, so that several tones may be transmitted at the same time. If the performer plays a piece of music in its various parts, every part will be reproduced: thus we have a compound or multiple telephone. This instrument has been used during the past winter to give concerts in cities when the performer was in a distant place. It has also been used as a multiple telegraph; as many as eight operators sending messages simultaneously over the same wire,--four in each direction,--without the slightest interference. BELL'S TELEPHONE. Prof. A. Graham Bell of Boston independently discovered the same means for producing multiple effects over the same wire; but it appears he did not practically work it out as completely as did Mr. Gray. But while the latter was chiefly employed in perfecting the method as a telegraphic system, Prof. Bell had set before himself the more difficult problem of transmitting speech. This he has actually accomplished, as we have so often been reminded during the past year. Thoroughly conversant with the acoustic researches of Helmholtz, and keeping in mind the complex form of the air vibrations produced by the human voice, he attempted to make these vibrations produce corresponding pulsations in an electric current in the manner analogous to the electric interrupter. Observing that membranes when properly stretched can vibrate to any kind of a sound, he sought to utilize them for this purpose. So did Reiss; but Reiss inserted the vibrating membrane into the circuit, and it was quite evident that such a plan would not answer, therefore the current must not be broken; but could an electric current be interfered with without breaking the connections? The well-known re-actions of magnets upon electrical currents, first noted by Oersted, and fully developed by Faraday, gave the clew to the solution. A piece of iron should be made to vibrate by means of sound vibrations, so as to affect an electro-magnet and induce corresponding electrical pulsations. FIRST FORM OF SPEAKING-TELEPHONE. A membrane of gold-beater's skin was tightly stretched over the end of a speaking-tube or funnel; on the middle of this membrane a piece of iron, N S, Fig. 13, was glued. In front of this piece of iron an electro-magnet M is so situated that its poles are opposite to it, but not quite touching it. One of the terminal wires of the electro-magnet goes to the battery B; the other goes to the receiving instrument R, which consists of a tubular electro-magnet, the coil being enclosed in a short tube of soft iron; the wire thence goes to the plate E´, which is sunk in the earth. On the top of R, at P, is a rather loose, thin disk of iron, which acts as an armature to the electro-magnet below it. [Illustration: FIG. 13.] Supposing that all the parts are thus properly connected, the current of electricity from the battery makes both M and R magnetic; the electro-magnet M will inductively make the piece of iron N S, a magnet, with its poles unlike those of the inducing electro-magnet; and the two will mutually attract each other. If now this piece of iron N S be made to move toward M, a current of electricity will be induced in the coils, which will traverse the whole circuit. This induced electricity will consist of a single wave or pulse, and its force will depend upon the velocity of the approach of N S to M. A like pulse of electricity will be induced in the coils when N S is made to move away from M; but this current will move through the circuit in the opposite direction, so that whether the pulsation goes from M to R, or from R to M, depends simply upon the direction of the motion of N S. The electricity thus generated in the wire by such vibratory movements varies in strength proportional to the movement of the armature; therefore the line wire between two places will be filled with electrical pulsation exactly like the aërial pulsations in structure. Fig. 10, p. 98, may be used to illustrate the condition of the wire through which the currents pass. The dark part may represent the strongest part of the wave, while the lighter part would show the weaker part of the wave. The chief difference would be, that electricity travels so fast, that what is there represented as one wave in air with a length of two feet would, in an electric wave, be more than fifty miles long. These induced electric currents are but very transient (see p. 31); and their effect upon the receiver R is to either increase or decrease the power of the magnet there, as they are in one direction or the other, and consequently to vary the attractive power exercised upon the iron plate armature. Let a simple sound be now made in the tube, consisting of 256 vibrations per second: the membrane carrying the iron will vibrate as many times, and so many pulses of induced electricity will be _imposed_ upon the constant current, which will each act upon the receiver, and cause so many vibrations of the armature upon it; and an ear held at P will hear the sound with the same pitch as that at the sending instrument. If two or more sound-waves act simultaneously upon the membrane, its motions must correspond with such combined motions; that is, its motions will be the resultant of all the sound-waves, and the corresponding pulsations in the current must reproduce at R the same effect. Now, when a person speaks in the tube, the membrane is thrown into vibrations more complex in structure than those just mentioned, differing only in number and intensity. The magnet will cause responses from even the minutest motion; and therefore an ear at R will hear what is said at the tube. This was the instrument exhibited at the Centennial Exposition at Philadelphia, and concerning which Sir William Thompson said on his return to England, "This is the greatest by far of all the marvels of the electric telegraph." The popular impression has been, concerning the telephone, that the _sound_ was in some way conveyed over the wire. It will be obvious to every one who may read this, that such is very far from being the case. The fact is, it is a beautiful example of the convertibility of forces from one form to another. There is first the initial vibratory mechanical motion of the air, which is imparted to the membrane carrying the iron. This motion is converted into electricity in the coil of wire surrounding the electro-magnet, and at the receiving-end is first effective as magnetism, which is again converted into vibratory motion of the iron armature, which motion is imparted to the air, and so becomes again a sound-wave in air like the original one. This was the first speaking-telephone that was ever constructed, so far as the writer is aware, but it was not a practicable instrument. Many sounds were not reproduced at all, and, according to the report of the judges at the Philadelphia Exposition, one needed to shout himself hoarse in order that he might be heard at all. THE AUTHOR'S TELEPHONE. For several years past my regularly recurring duties have taken me over the various subjects treated of in this book, and each one has been extensively illustrated in an experimental way, and a considerable number of new pieces of apparatus and new experiments to exhibit their phenomena have been devised by me. Among these, I would mention the following:-- 1. Measurement of the elongation of a magnetized bar. 2. A magneto-electric telegraph. 3. An electro-magnetic instrument for demonstrating the rotation of the earth. 4. The permanent magnetism of the magnetic phantom. 5. The convertibility of sound into electricity. 6. The induction of a vibrating magnet upon an electric circuit. 7. The origination of electric waves in a circuit by a sounding magnet. 8. The discovery of the action of the air in a sounding organ-pipe. 9. Two or three methods for studying the vibrations of membranes. 10. Lissajous forks for enlarged projections of sound vibrations. As soon, therefore, as I gave attention to the subject of telephony, I was able, with a few preliminary experiments, to determine the proper conditions for the transmission of speech in an electric circuit; and, without the slightest knowledge of the mechanism which Prof. Bell had used, I devised the following arrangement for a speaking-telephone. [Illustration: FIG. 14.--MY FIRST SPEAKING TELEPHONE.] [Illustration: FIG. 14.--END VIEW.] My first speaking-telephone, Fig. 14, consisted of a magnet made out of half-inch round steel bent into a U form, having the poles about two inches apart. Over these were slipped two bobbins taken from an old telegraph register, and were already fitted to a half-inch core. These bobbins, two inches and a half long, were wound with cotton-covered copper wire, No. 23, each bobbin containing about 150 feet. This magnet, with the bobbins slipped upon its poles, was made fast to a post two or three inches high. The steel was made as strongly magnetic as was possible, and would hold up three or four times its own weight. In front of the poles, a sheet of thin steel, one-fiftieth of an inch thick, was made fast to an upright board having a hole cut through it three and a half inches in diameter (Fig. 14, end view); the plate was screwed tightly to this board, so as to cover the hole; and the middle of the hole was at the same height as the two poles of the magnet. The wires from the two bobbins were connected, as if to make an electro-magnet; while the two free terminals were to be connected with the line-wires. Of course there were two of these instruments, both alike; and talking and singing were reproduced with these. A very great number of experiments have been made to determine the best conditions for each of the essential parts,--the size and strength of the magnet, the size of the bobbins, as to length and fineness of wire, the best thickness for the plate for absorbing the vibrations, &c.; and it is really surprising, how little is the difference between very wide limits. The following directions will enable any one to construct a speaking-telephone with which good results may be obtained. The specifications will be for only one instrument; though of course two instruments made alike will be necessary for any purposes of speaking or other signals. [Illustration: FIG. 15.] [Illustration: FIG. 16.] Procure three common horse-shoe magnets about six inches long, all of the same size; these retail in the market at about a dollar apiece. They should be strong enough to hold up several times their own weight each. Next, have turned out of good hard wood,--such as maple or boxwood,--two spools not over half an inch long and an inch and a half broad, the sides cut square both inside and out, as shown at S, Fig. 15; a hole the third of an inch in diameter is to be made through the spool. Into this hole is to be fitted a short rod of soft iron, I, about an inch long, which should be a little rounded at the outer end. The bobbins may be wound with as much insulated copper wire as they will hold. The wire may be from the one-fortieth to the one-fiftieth of an inch in diameter, as is most convenient to obtain, the latter size being preferable. The resistance of such bobbins will probably be from two to three ohms each. The soft-iron core I must project backwards far enough to be clamped between the two outer magnets 1 and 3, while the inner one, 2, is drawn back. When the bobbins are in their places, and are clamped between the upper and lower magnets, they will stand as shown in Fig. 16, where the view is from above; the magnets being buttoned down to the block they rest on (see Fig. 17), which at the same time holds the soft-iron rods with the bobbins upon them. The wires on these coils must be connected in the same way they would be in order to make opposite poles of their outer ends, if a current of electricity were to be sent through the coils. An upright board B (Fig. 17) six or seven inches square, having a round hole four inches in diameter cut out from the middle of it, must be fixed near the end of the base-board; and over this hole is to be screwed _tightly_ a piece of thin sheet iron or steel; it may be from the one-twentieth to the one-fiftieth of an inch in thickness. It does not seem to make much difference about the thickness of this plate. I have generally got the best results from a plate one-fiftieth of an inch thick. The upright board carrying this plate must be very rigid, otherwise the plate will be kept tight to the magnets all the time; and one of the conditions of success in working is, that this plate shall be as close as possible to the magnet-ends, but not to touch: therefore fix the board tight, and adjust the magnets by means of the button shown on top of them in the perspective figure. [Illustration: FIG. 17.] The sounds to be transmitted, of whatever sort they may be, are to be made on the side P, Fig. 16; and likewise, when the instrument is used as a receiver, the ear is to be applied at the same place. A tube about two inches in diameter may be made fast to the front of the board, in a line with the centre of the plate; this will aid somewhat in hearing. When two or three persons are to sing, it will be best to have each one supplied with a tube to sing through; one end of the tube to be placed close to the front of the plate. The sound of musical instruments, such as the flute and the cornet, will be reproduced much louder, if the front of such instrument be allowed to rest upon the rim of the hole in the board, just in front of the plate. It is noticeable that low talking can be heard more distinctly than when a great effort is made; but the sounds though distinct are not strong at any time, and other sounds seriously interfere with hearing. It is probable that some way will hereafter be devised for increasing the usefulness of the invention by increasing the volume of sound. On account of the weakness of the sound it becomes necessary to provide a call to attract the attention of one in the room. This may be accomplished by having a small electric bell worked by a one or two cell battery. Another way which I have found to be quite as efficient is to have a rod of iron or steel about a foot long, and half an inch in diameter, bent into a U form. When this is held by the bend, and struck upon the floor or with a stick, it vibrates powerfully; and if one of its prongs be permitted to strike against the plate P, Fig. 16, the sound will be reproduced loud enough to hear over a large room. I have never failed to call with this when any one was in the same room with the telephone. Wherever a telephone circuit has been made upon telegraph poles having other wires upon them, the inductive actions of the currents upon the other wires has been found to seriously interfere with the action of the telephones, inasmuch as the latter reproduce every other message. One skilled in reading by sound in the ordinary way can read through the telephone what message is travelling in a neighboring wire. Messages may be thus read upon wires as far distant as ten feet from the telephone circuit. It there fore seems to be essential that each telephone circuit should be isolated from every other one, else there can be no secrecy in messages. A very interesting effect was noticed one night when there was a bright aurora display. There was a continuous current through the wires, accompanied with sounds which increased in intensity as the bright streamers passed by. This will probably lead to some important results in science. In all probability the telephone is as much in its infancy as was ordinary telegraphy in 1840. Since that time the sciences of electricity and magnetism have had the most of their growth, and telegraphy has kept pace with the advancing knowledge until its commercial importance is second to no other agency. Very many important principles that are invaluable in telegraphy to-day were wholly unknown in 1840; but it may here be noted that in the telephone, as it now is, there is not a single principle that was not well enough known in 1840. This will be apparent to one who follows out the phenomena from the sender to the receiver. First, the sound in air causing a corresponding movement in a solid body, iron. This iron, acting inductively upon a magnet, originates magneto-electric currents in a wire helix about it; and these travel to another helix, and, re-acting upon the magnet in it, have electro-magnetic effects, and increase and decrease the strength of the magnet; and this variable magnetism affects the plate of iron in front of that magnet, and makes it to vibrate in a corresponding manner, and thus to restore to the air in one place the vibrations absorbed from the air in another place. To some it may seem strange that a simple thing as the telephone is, involving nothing but principles familiar enough to every one interested in physical science, should have waited nearly forty years to be invented. The reason is probably this: Men of science, as a rule, do not feel called upon to apply the principles which they may discover. They are content to be _discovering_, not _inventing_. Now, the schools of the country ought to make the youth quite familiar with the general principles of physical science, that the inventive ones--and there are many such--may apply them intelligently. Mechanism is all that stands between us and aërial navigation; all that is necessary to reproduce human speech in writing; and all that is needed to realize completely the prophetic picture of the "Graphic," of the orator who shall at the same instant address an audience in every city in the world. * * * * * Transcriber's Notes: The musical flat symbol is represented in the text by [flat]. Page 17, "propererties" changed to "properties" (there are other properties) Page 42, "muturally" changed to "mutually" (bodies would mutually) Page 106, "outby" changed to "out by" (given out by the) 
23292	----	Transcriber's Note: Minor typographical errors have been corrected without note. Dialect spellings, contractions and discrepancies have been retained. TED AND THE TELEPHONE By Sara Ware Bassett _The Invention Series_ PAUL AND THE PRINTING PRESS STEVE AND THE STEAM ENGINE TED AND THE TELEPHONE [Illustration: "Would you like to go to college if you could?" persisted the elder man. FRONTISPIECE. _See page_ 178.] The Invention Series TED AND THE TELEPHONE By SARA WARE BASSETT WITH ILLUSTRATIONS BY WILLIAM F. STECHER BOSTON LITTLE, BROWN, AND COMPANY 1922 _Copyright, 1922_, BY LITTLE, BROWN, AND COMPANY. _All rights reserved_ Published April, 1922 PRINTED IN THE UNITED STATES OF AMERICA TO THE MEMORY OF EDWIN T. HOLMES WHO PLAYED A PART IN THE WONDERFUL TELEPHONE STORY, THIS BOOK IS AFFECTIONATELY INSCRIBED. S. W. B. It gives me much pleasure to acknowledge the generosity of Mr. Thomas Augustus Watson, the associate of and co-worker with Mr. Alexander Graham Bell, who has placed at my disposal his "Birth and Babyhood of the Telephone." Also the courtesy of Mrs. Edwin T. Holmes who has kindly allowed me to make use of her husband's book: "A Wonderful Fifty Years." THE AUTHOR. CONTENTS CHAPTER PAGE I AN UNHERALDED CHAMPION 1 II TED RENEWS OLD TIMES 11 III GOING TO HOUSEKEEPING 21 IV THE FIRST NIGHT IN THE SHACK 35 V A VISITOR 49 VI MORE GUESTS 60 VII MR. LAURIE 76 VIII DIPLOMACY AND ITS RESULTS 94 IX THE STORY OF THE FIRST TELEPHONE 106 X WHAT CAME AFTERWARD 122 XI THE REST OF THE STORY 141 XII CONSPIRATORS 152 XIII WHAT TED HEARD 163 XIV THE FERNALDS WIN THEIR POINT 173 XV WHAT CAME OF THE PLOT 189 XVI ANOTHER CALAMITY 199 XVII SURPRISES 213 ILLUSTRATIONS "Would you like to go to college if you could?" persisted the elder man _Frontispiece_ "You can't be spreadin' wires an' jars an' things round my room!" protested Mr. Turner Page 9 Soon he came within sight of the shack which stood at the water's edge " 27 He heard an answering shout and a second later saw Ted Turner dash through the pines " 88 TED AND THE TELEPHONE CHAPTER I AN UNHERALDED CHAMPION Ted Turner lived at Freeman's Falls, a sleepy little town on the bank of a small New Hampshire river. There were cotton mills in the town; in fact, had there not been probably no town would have existed. The mills had not been attracted to the town; the town had arisen because of the mills. The river was responsible for the whole thing, for its swift current and foaming cascades had brought the mills, and the mills in turn had brought the village. Ted's father was a shipping clerk in one of the factories and his two older sisters were employed there also. Some day Ted himself expected to enter the great brick buildings, as the boys of the town usually did, and work his way up. Perhaps in time he might become a superintendent or even one of the firm. Who could tell? Such miracles did happen. Not that Ted Turner preferred a life in the cotton mills to any other career. Not at all. Deep down in his soul he detested the humming, panting, noisy place with its clatter of wheels, its monotonous piecework, and its limited horizon. But what choice had he? The mills were there and the only alternative before him. It was the mills or nothing for people seldom came to live at Freeman's Falls if they did not intend to enter the factories of Fernald and Company. It was Fernald and Company that had led his father to sell the tumble-down farm in Vermont and move with his family to New Hampshire. "There is no money in farming," announced he, after the death of Ted's mother. "Suppose we pull up stakes and go to some mill town where we can all find work." And therefore, without consideration for personal preferences, they had looked up mill towns and eventually settled on Freeman's Falls, not because they particularly liked its location but because labor was needed there. A very sad decision it was for Ted who had passionately loved the old farm on which he had been born, the half-blind gray horse, the few hens, and the lean Jersey cattle that his father asserted ate more than they were worth. To be cooped up in a manufacturing center after having had acres of open country to roam over was not an altogether joyous prospect. Would there be any chestnut, walnut, or apple trees at Freeman's Falls, he wondered. Alas, the question was soon answered. Within the village there were almost no trees at all except a few sickly elms and maples whose foliage was pale for want of sunshine and grimy with smoke. In fact, there was not much of anything in the town save the long dingy factories that bordered the river; the group of cheap and gaudy shops on the main street; and rows upon rows of wooden houses, all identical in design, walling in the highway. It was not a spot where green things flourished. There was not room for anything to grow and if there had been the soot from the towering chimneys would soon have settled upon any venturesome leaf or flower and quickly shrivelled it beneath a cloak of cinders. Even the river was coated with a scum of oil and refuse that poured from the waste pipes of the factories into the stream and washed up along the shores which might otherwise have been fair and verdant. Of course, if one could get far enough away there was beauty in plenty for in the outlying country stretched vistas of splendid pines, fields lush with ferns and flowers, and the unsullied span of the river, where in all its mountain-born purity it rushed gaily down toward the village. Here, well distant from the manufacturing atmosphere, were the homes of the Fernalds who owned the mills, the great estates of Mr. Lawrence Fernald and Mr. Clarence Fernald who every day rolled to their offices in giant limousines. Everybody in Freeman's Falls knew them by sight,--the big boss, as he was called, and his married son; and everybody thought how lucky they were to own the mills and take the money instead of doing the work. At least, that was what gossip said they did. Unquestionably it was much nicer to live at Aldercliffe, the stately colonial mansion of Mr. Lawrence Fernald; or at Pine Lea, the home of Mr. Clarence Fernald, where sweeping lawns, bright awnings, gardens, conservatories, and flashing fountains made a wonderland of the place. Troupes of laughing guests seemed always to be going and coming at both houses and there were horses and motor-cars, tennis courts, a golf course, and canoes and launches moored at the edge of the river. Freeman's Falls was a very stupid spot when contrasted with all this jollity. It must be far pleasanter, too, when winter came to hurry off to New York for the holidays or to Florida or California, as Mr. Clarence Fernald frequently did. With money enough to do whatever one pleased, how could a person help being happy? And yet there were those who declared that both Mr. Lawrence and Mr. Clarence Fernald would have bartered their fortunes to have had the crippled heir to the Fernald millions strong like other boys. Occasionally Ted had caught a glimpse of this Laurie Fernald, a fourteen-year-old lad with thin, colorless face and eyes that were haunting with sadness. In the village he passed as "the poor little chap" or as "poor Master Laurie" and the employees always doffed their caps to him because they pitied him. Whether one liked Mr. Fernald or Mr. Clarence or did not, every one united in being sorry for Mr. Laurie. Perhaps the invalid realized this; at any rate, he never failed to return the greetings accorded him with a smile so gentle and sweet that it became a pleasure in the day of whomsoever received it. It was said at the factories that the reason the Fernalds went to New York and Florida and California was because of Mr. Laurie; that was the reason, too, why so many celebrated doctors kept coming to Pine Lea, and why both Mr. Fernald and Mr. Clarence were often so sharp and unreasonable. In fact, almost everything the Fernalds did or did not do, said or did not say, could be traced back to Mr. Laurie. From the moment the boy was born--nay, long before--both Mr. Lawrence Fernald for whom he was named, and his father, Mr. Clarence Fernald, had planned how he should inherit the great mills and carry on the business they had founded. For years they had talked and talked of what should happen when Mr. Laurie grew up. And then had come the sudden and terrible illness, and after weeks of anxiety everybody realized that if Mr. Laurie lived he would be fortunate, and that he would never be able to carry on any business at all. In what hushed tones the townspeople talked of the tragedy and how they speculated on what the Fernalds would do _now_. And how surprised the superintendent of one of the mills (who, by the way, had six husky boys of his own) had been to have Mr. Lawrence Fernald bridle with rage when he said he was sorry for him. A proud old man was Mr. Fernald, senior. He did not fancy being pitied, as his employees soon found out. Possibly Mr. Clarence Fernald did not like it any better but whether he did or not he at least had the courtesy not to show his feelings. Thus the years had passed and Mr. Laurie had grown from childhood to boyhood. He could now ride about in a motor-car if lifted into it; but he could still walk very little, although specialists had not given up hope that perhaps in time he might be able to do so. There was a rumor that he was strapped into a steel jacket which he was forced to wear continually, and the mill hands commented on its probable discomfort and wondered how the boy could always keep so even-tempered. For it was unavoidable that the large force of servants from Aldercliffe and Pine Lea should neighbor back and forth with the townsfolk and in this way many a tale of Mr. Laurie's rare disposition reached the village. And even had not these stories been rife, anybody could easily have guessed the patience and sweetness of Mr. Laurie's nature from his smile. Among the employees of Fernald and Company he was popularly known as the Little Master and between him and them there existed a friendliness which neither his father nor his grandfather had ever been able to call out. The difference was that for Mr. Lawrence Fernald the men did only what they were paid to do; for Mr. Clarence they did fully what they were paid to do; and for Mr. Laurie they would gladly have done what they were paid to do and a great deal more. "The poor lad!" they murmured one to another. "The poor little chap!" Of course it followed that no one envied Mr. Laurie his wealth. How could they? One might perhaps envy Mr. Fernald, senior, or Mr. Clarence; but never Mr. Laurie even though the Fernald fortune and all the houses and gardens, with their miles of acreage, as well as the vast cotton mills would one day be his. Even Ted Turner, poor as he was, and having only the prospect of the factories ahead of him, never thought of wishing to exchange his lot in life for that of Mr. Laurie. He would rather toil for Fernald and Company to his dying day than be this weak, dependent creature who was compelled to be carried about by those stronger than himself. Nevertheless, in spite of this, there were intervals when Ted did wish he might exchange houses with Mr. Laurie. Not that Ted Turner coveted the big colonial mansion, or its fountains, its pergolas, its wide lawns; but he did love gardens, flowers, trees, and sky, and of these he had very little. He was, to be sure, fortunate in living on the outskirts of the village where he had more green and blue than did most of the mill workers. Still, it was not like Vermont and the unfenced miles of country to which he had been accustomed. A small tenement in Freeman's Falls, even though it had steam heat and running water, was in his opinion a poor substitute for all that had been left behind. But Ted's father liked the new home better, far better, and so did Ruth and Nancy, his sisters. Many a time the boy heard his father congratulating himself that he was clear of the farm and no longer had to get up in the cold of the early morning to feed and water the stock and do the milking. And Ruth and Nancy echoed these felicitations and rejoiced that now there was neither butter to churn nor hens to care for. Even Ted was forced to confess that Freeman's Falls had its advantages. Certainly the school was better, and as his father had resolved to keep him in it at least a part of the high-school term, Ted felt himself to be a lucky boy. He liked to study. He did not like all studies, of course. For example, he detested Latin, French, and history; but he revelled in shop-work, mathematics, and the sciences. There was nothing more to his taste than putting things together, especially electrical things; and already he had tried at home several crude experiments with improvised telegraphs, telephones, and wireless contrivances. Doubtless he would have had many more such playthings had not materials cost so much, money been so scarce, and Ruth and Nancy so timid. They did not like mysterious sparks and buzzings in the pantry and about the kitchen and told him so in no uncertain terms. "The next thing you know you'll be setting the house afire!" Ruth had asserted. "Besides, we've no room for wires and truck around here. You'll have to take your clutter somewhere else." And so Ted had obediently bundled his precious possessions into the room where he slept with his father only to be as promptly ejected from that refuge also. "You can't be spreadin' wires an' jars an' things round my room!" protested Mr. Turner with annoyance. [Illustration: "You can't be spreadin' wires an' jars an' things round my room!" protested Mr. Turner. _Page_ 9.] It did not seem to occur to him that it was Ted's room as well,--the only room the boy had. Altogether, his treasures found no welcome anywhere in the tiny apartment, and at length convinced of this, Ted took everything down and stowed it away in a box beneath the bed, henceforth confining his scientific adventures to the school laboratories where they might possibly have remained forever but for Mr. Wharton, the manager of the farms at Aldercliffe and Pine Lea. CHAPTER II TED RENEWS OLD TIMES Mr. Wharton was about the last person on earth one would have connected with boxes of strings and wires hidden away beneath beds. He was a graduate of a Massachusetts agricultural college; a keen-eyed, quick, impatient creature toward whom people in general stood somewhat in awe. He had the reputation of being a top-notch farmer and those who knew him declared with zest that there was nothing he did not know about soils, fertilizers, and crops. There was no nonsense when Mr. Wharton appeared on the scene. The men who worked for him soon found that out. You didn't lean on your hoe, light your pipe, and hazard the guess that there would be rain to-morrow; you just hoed as hard as you could and did not stop to guess anything. Now it happened that it was haying time both at Aldercliffe and Pine Lea and the rumor got abroad that the crop was an unusually heavy one; that Mr. Wharton was short of help and ready to hire at a good wage extra men from the adjoining village. Mr. Turner brought the tidings home from the mill one June night when he returned from work. "Why don't you try for a job up at Aldercliffe, my lad?" concluded he, after stating the case. "Ever since you were knee-high to a grasshopper you had a knack for pitching hay. Besides, you'd make a fine bit of money and the work would be no heavier than handling freight down at the mills. You've got to work somewhere through your summer vacation." He made the latter statement as a matter of course for a matter of course it had long since become. Ted always worked when he was not studying. Vacations, holidays, Saturdays, he was always busy earning money for if he had not been, there would have been no chance of his going to school the rest of the time. Sometimes he did errands for one of the dry-goods stores; sometimes, if there were a vacancy, he helped in Fernald and Company's shipping rooms; sometimes he worked at the town market or rode about on the grocer's wagon, delivering orders. By one means or another he had usually contrived, since he was quite a small boy, to pick up odd sums that went toward his clothes and "keep." As he grew older, these sums had increased until now they had become a recognized part of the family income. For it was understood that Ted would turn in toward the household expenses all that he earned. His father had never believed in a boy having money to spend and even if he had every cent which the Turners could scrape together was needed at home. Ted knew well how much sugar and butter cost and therefore without demur he cheerfully placed in the hands of his sister Ruth, who ran the house, every farthing that was given him. From childhood this sense of responsibility had always been in his background. He had known what it was to go hungry that he might have shoes and go without shoes that he might have underwear. Money had been very scarce on the Vermont farm, and although there was now more of it than there ever had been in the past, nevertheless it was not plentiful. Therefore, as vacation was approaching and he must get a job anyway, he decided to present himself before Mr. Wharton and ask for a chance to help in harvesting the hay crops at Aldercliffe and Pine Lea. "You are younger than the men I am hiring," Mr. Wharton said, after he had scanned the lad critically. "How old are you?" "Fourteen." "I thought as much. What I want is men." "But I have farmed all my life," protested Ted with spirit. "Indeed!" the manager exclaimed not unkindly. "Where?" "In Vermont." "You don't say so! I was born in the Green Mountains," was the quick retort. "Where did you live?" "Newfane." Instantly the man's face lighted. "I know that place well. And you came from Newfane here? How did you happen to do that?" "My father could not make the farm pay and we needed money." "Humph! Were you sorry to give up farming?" "Yes, sir. I didn't want to come to Freeman's Falls. But," added the boy brightening, "I like the school here." The manager paused, studying the sharp, eager face, the spare figure, and the fine carriage of the lad before him. "Do you like haying?" asked he presently. "Not particularly," Ted owned with honesty. Mr. Wharton laughed. "I see you are a human boy," he said. "If you don't like it, why are you so anxious to do it now?" "I've got to earn some money or give up going to school in the fall." "Oh, so that's it! And what are you working at in school that is so alluring?" demanded the man with a quizzical glance. "Electricity." "Electricity!" "Wireless, telegraphs, telephones, and things like that," put in Ted. For comment Mr. Wharton tipped back in his chair and once more let his eye wander over the boy's face; then he wheeled abruptly around to his desk, opened a drawer, and took out a yellow card across which he scrawled a line with his fountain pen. "You may begin work to-morrow morning," he remarked curtly. "If it is pleasant, Stevens will be cutting the further meadow with a gang of men. Come promptly at eight o'clock, prepared to stay all day, and bring this card with you." He waved the bit of pasteboard to and fro in the air an instant to be certain that the ink on it was dry and afterward handed it to Ted. Instinctively the boy's gaze dropped to the message written upon it and before he realized it he had read the brief words: "Ted Turner. He says he has farmed in Vermont. If he shows any evidence of it keep him. If not turn him off. Wharton." The man in the chair watched him as he read. "Well?" said he. "I beg your pardon, sir. I did not mean to read it," Ted replied with a start. "I'm very much obliged to you for giving me the job." "I don't see that you've got it yet." "But I shall have," asserted the lad confidently. "All I asked was a chance." "That's all the world gives any of us," responded the manager gruffly, as he drew forth a sheet of paper and began to write. "Nobody can develop our brains, train our muscles, or save our souls but ourselves." With this terse observation he turned his back on the boy, and after loitering a moment to make sure that he had nothing more to say, the lad slipped away, triumphantly bearing with him the coveted morsel of yellow pasteboard. That its import was noncommittal and even contained a tang of skepticism troubled him not a whit. The chief thing was that he had wrested from the manager an opportunity, no matter how grudgingly accorded, to show what he was worth. He could farm and he knew it and he had no doubt that he could demonstrate the fact to any boss he might encounter. Therefore with high courage he was promptly on hand the next morning and even before the time assigned he approached Stevens, the superintendent. "What do you want, youngster?" demanded the man sharply. He was in a hurry and it was obvious that something had nettled him and that he was in no humor to be delayed. "I came to help with the haying." "We don't want any boys as young as you," Stevens returned, moving away. "I've a card from Mr. Wharton." "A card, eh? Why didn't you say so in the first place? Shell it out." Shyly Ted produced his magic fragment of paper which the overseer read with disapproval in his glance. "Well, since Wharton wants you tried out, you can pitch in with the crowd," grumbled he. "But I still think you're too young. I've had boys your age before and never found them any earthly use. However, you won't be here long if you're not--that's one thing. You'll find a pitchfork in the barn. Follow along behind the men who are mowing and spread the grass out." "I know." "Oh, you do, do you! Trust people your size for knowing everything." To the final remark the lad vouchsafed no reply. Instead he moved away and soon returned, fork in hand. What a flood of old memories came surging back with the touch of the implement! Again he was in Vermont in the stretch of mowings that fronted the old white house where he was born. The scent of the hay in his nostrils stirred him like an elixir, and with a thrill of pleasure he set to work. He had not anticipated toiling out there in the hot sunshine at a task which he had always disliked; but to-day, by a strange miracle, it did not seem to be a task so much as a privilege. How familiar the scene was! As he approached the group of older men it took him only a second to see where he was needed and he thrust his pitchfork into the swath at his feet with a swing of easy grace. "Guess you've done this job before," called a man behind him after he had worked for an interval. "Yes, I have." "You show it," was the brief observation. They moved on in silence up the field. "Where'd you learn to handle that fork, sonny?" another voice shouted, as they neared the farther wall. "In Vermont," laughed Ted. "I judged as much," grunted the speaker. "They don't train up farmers of your size in this part of the world." Ted flushed with pleasure and for the first time he stopped work and mopped the perspiration from his forehead. He was hot and thirsty but he found himself strangely exhilarated by the exercise and the sweet morning air and sunshine. Again he took up his fork and tossed the newly cut grass up into the light, spreading it on the ground with a methodical sweep of his young arm. The sun had risen higher now and its dazzling brilliance poured all about him. Up and down the meadow he went and presently he was surprised to find himself alone near the point from which he had started. His fellow-laborers were no longer in sight. The field was very still and because it was, Ted began to whistle softly to himself. He was startled to hear a quiet laugh at his elbow. "Don't you ever eat anything, kid?" Mr. Wharton was standing beside him, a flicker of amusement in his gray eyes. "I didn't know it was noon," gasped Ted. "We'll have to tie an alarm clock on you," chuckled the manager. "The gang stopped work a quarter of an hour ago." "I didn't notice they had." The boy flushed. He felt very foolish to have been discovered working there all by himself in this ridiculous fashion. "I wanted to finish this side of the field and I forgot about the time," he stammered apologetically. "Have you done it to your satisfaction?" "Yes, I'm just through." For the life of him Ted could not tell whether the manager was laughing at him or not. He kicked the turf sheepishly. "Aren't you tired?" inquired Mr. Wharton at length. "No--at least--well, I haven't thought about it. Perhaps I am a little." "And well you may be. You've put in a stiff morning's work. You'd better go and wash up now and eat your lunch. Take your full hour of rest. No matter if the others do get back here before you. Stevens says you are worth any two of them, anyway." "It's just that I'm used to it," was the modest reply. "We'll let it go at that," Mr. Wharton returned ambiguously. "And one thing more before you go. You needn't worry about staying on. We can use you one way or another all summer. There'll always be work for a boy who knows how to do a job well." CHAPTER III GOING TO HOUSEKEEPING Thus it came about that Ted Turner began the long, golden days of his summer vacation at the great estates of the Fernalds, and soon he had made himself such an indispensable part of the farming staff that both Mr. Wharton and Mr. Stevens came to rely on him for many services outside of those usually turned over to the men. "Just step over to the south lot at Pine Lea, Ted, and see if those fellows are thinning the beets properly," Mr. Wharton would say. "I gave them their orders but they may not have taken them in. You know how the thing should be done. Sing out to them if they are not doing the job right." Or: "Mr. Stevens and I shall be busy this morning checking up the pay roll. Suppose you have an eye on the hilling up of the potatoes, Ted. Show the men how you want it done and start them at it. I'll be over later to see how it's going." Frequently, instead of working, the boy was called in to give an opinion on some agricultural matter with which he had had experience. "We are finding white grubs in the corner of the Pine Lea garden. They are gnawing off the roots of the plants and making no end of trouble. What did you do to get rid of them when you were up in Vermont?" "Salt and wood ashes worked better than anything else," Ted would reply modestly. "It might not be any good here but we had luck with it at home." "We can try it, at least. You tell Mr. Stevens what the proportions are and how you applied it." And because the advice was followed by a successful extermination of the plague, the lad's prestige increased and he was summoned to future conclaves when troublesome conditions arose. Now and then there was a morning when Mr. Stevens would remark to Mr. Wharton: "I've got to go to the Falls to-day to see about some freight. Ted Turner will be round here, though, and I guess things will be all right. The men can ask him if they want anything." And so it went. First Ted filled one corner, then another. He did errands for Mr. Wharton, very special errands, that required thought and care, and which the manager would not have entrusted to every one. Sometimes he ventured valuable suggestions which Mr. Stevens, who really had had far less farming experience than he, was only too grateful to follow. If the boy felt at all puffed up by the dependence placed upon him, he certainly failed to show it. On the contrary he did his part enthusiastically, faithfully, generously, and without a thought of praise or reward. Although he was young to direct others, when he did give orders to the men he was tactful and retiring enough to issue his commands in the form of wishes and immediately they were heeded without protest. He never shirked the hard work he asked others to perform but was always ready to roll up the sleeves of his blue jeans and pitch with vigor into any task, no matter how menial it was. Had he been arrogant and made an overbearing use of his authority, the men would quickly have rated him as a conceited little popinjay, the pet of the boss, and made his life miserable; but as he remained quite unspoiled by the preference shown him and exhibited toward every one he encountered a kindly sympathy and consideration, the workmen soon accepted him as a matter of course and even began to turn to him whenever a dilemma confronted them. Perhaps Ted was too genuinely interested in what he was doing to think much about himself or realize that the place he held was an unusual one. At home he and his father had threshed out many a problem together and each given to it the best his brain had to offer, without thought of the difference in their ages. Sometimes Ted's way proved the better, sometimes Mr. Turner's. Whichever plan promised to bring the more successful results was followed without regard for the years of him who had sponsored it. They were working together and for the same goal and what did it matter which of them had proposed the scheme they finally followed? To get the work completed and lay low the obstacles in their path were the only issues of importance. So it was now. Things at Aldercliffe and Pine Lea must be done and done well, and only what furthered that end counted. Nevertheless, Ted would not have been a human boy had he not been pleased when some idea of his was adopted and found to be of use; this triumph, however, was less because the programme followed was his own than because it put forward the enterprise in hand. There was a satisfaction in finding the key to a balking problem and see it cease to be a problem. It was fun, for example, to think about the potatoes and then say to Mr. Wharton: "Do you know, Mr. Wharton, I believe if we tried a different spray on that crop that isn't doing well it might help matters." And when the new concoction was tried and it did help matters, what a glow of happiness came with the success! What wonder that as the days passed, the niche awarded the lad grew bigger and bigger! "There is no way you could come up here and live, is there, Ted?" Mr. Wharton inquired one day. "I'd give a good deal to have you here on the spot. Sometimes I want to talk with you outside working hours and I can't for the life of me lay hands on you. It's the deuce of a way to Freeman's Falls and you have no telephone. If you were here----" He paused meditatively, then continued, "There's a little shack down by the river which isn't in use. You may remember seeing it. It was started years ago as a boathouse for Mr. Laurie's canoes and then--well, it was never finished. It came to me the other day that we might clean it up, get some furnishings, and let you have it. How would the notion strike you?" Ted's eyes sparkled. "I'd like it of all things, sir!" returned he instantly. "You wouldn't be timid about sleeping off there by yourself?" "No, indeed!" "Well, well! I had no idea you would listen to such a plan, much less like it. Suppose you go down there to-day and overhaul the place. Find out what would be required to make you comfortable and we will see what we can do about it. I should want you fixed up so you would be all right, you know. While we could not afford to go into luxuries, there would be no need for you to put up with makeshifts." "But I am quite used to roughing it," protested Ted. "I've often camped out." "Camping is all very well for a while but after a time it ceases to be a joke. No, if you move up here to accommodate us, you must have decent quarters. Both Mr. Fernald and Mr. Clarence would insist on that, I am certain. So make sure that the cabin is tight and write down what you think it would be necessary for you to have. Then we'll see about getting the things for you." "You are mighty good, sir." "Nonsense! It is for our own convenience," Mr. Wharton replied gruffly. "Shall I--do you mean that I am to go over there after work to-night?" "No. Go now. Cut along right away." "But I was to help Mr. Stevens with the----" "Stevens will have to get on without you. Tell him so from me. You can say I've set you at another job." With springing step Ted hurried away. He was not sorry to exchange the tedious task of hoeing corn for the delightful one of furnishing a domicile for himself. What sport it would be to have at last a place which he could call his own! He could bring his books from home, his box of electrical things--all his treasures--and settle down in his kingdom like a young lord. He did not care at all if he had only a hammock to sleep in. The great satisfaction would be to be his own master and monarch of his own realm, no matter how tiny it was. Like lightning his imagination sped from one dream to another. If only Mr. Wharton would let him run some wires from the barn to the shack, what electrical contrivances he could rig up! He could then light the room and heat it, too; he could even cook by electricity. Probably, however, Mr. Wharton would consider such a notion out of the question and much too ambitious. Even though the Fernalds had an electrical plant of their own, such a luxury was not to be thought of. A candle would do for lighting, of course. [Illustration: Soon he came within sight of the shack which stood at the water's edge. _Page_ 27.] Busy with these thoughts and others like them he sped across the meadow and through the woods toward the river. He was not content to walk the distance but like a child leaped and ran with an impatience not to be curbed. Soon he came within sight of the shack which stood at the water's edge, mid-way between Aldercliffe and Pine Lea, and was sheltered from view by a grove of thick pines. Its bare, boarded walls had silvered from exposure to the weather until it was scarcely noticeable against the gray tree trunks. Nevertheless, its crude, rough sides, its staring windows, and its tarred roof looked cheerless and deserted enough. But for Ted Turner it possessed none of these forbidding qualities. Instead of being a hermitage it seemed a paradise, a fairy kingdom, the castle of a knight's tale! Thrusting the key which Mr. Wharton had given him into the padlock, he rolled open the sliding door and intermingled odors of cedar, tar, and paint greeted him. The room was of good size and was neatly sheathed as an evident preparation for receiving a finish of stain which, however, had never been put on. There were four large windows closed in by lights of glass, a rough board floor, and a fireplace of field stone. Everywhere was dirt, cobwebs, sawdust, and shavings; and scattered about so closely there was scarcely space to step was a litter of nails, fragments of boards, and a conglomeration of tin cans of various sizes. Almost any one who beheld the chaos would have turned away discouraged. But not so Ted! The disorder was of no consequence in his eyes. Through all its dinginess and confusion he saw that the roof was tight, the windows whole, and the interior quite capable of being swept out, scrubbed and put in order. That was all he wanted to know. Why, the place could be made into a little heaven! Already he could see it transformed into a dwelling of the utmost comfort. He had remodelled many a worse spot,--the barn loft in Vermont, for example, and made it habitable. One had only to secure a table, a chair or two, build a bunk and get a mattress, and the trick was turned. How proud he should be to have such a dwelling for his own! He could hardly restrain himself from rolling up his sleeves and going to work then and there. Fearing, however, that Mr. Wharton might be awaiting his report, he reluctantly closed the door again, turned the key in it, and hurried back to the manager's office. "Well," inquired the elder man, spinning around in his desk chair as the boy entered and noting the glow in the youthful face, "how did you find things at the shack? Any hope in the place?" "Hope!" repeated Ted. "Why, sir, the house is corking! Of course, it is dirty now but I could clean it up and put it in bully shape. All I'd need would be to build a bunk, get a few pieces of furniture, and the place would be cosy as anything. If you'll say the word, I'll start right in to-night after work and----" "Why wait until to-night?" came drily from the manager. "Why--er--I thought perhaps--you see there is the corn----" "Never mind the corn," Mr. Wharton interrupted. "You mean I could go right ahead now?" asked Ted eagerly. "Certainly. You are doing this for our accommodation, not for your own, and there is no earthly reason why you should perform the work outside your regular hours." "But it is for my accommodation, too," put in the lad with characteristic candor. "I am very glad if it happens to be," nodded Mr. Wharton. "So much the better. But at any rate, you are not going to take your recreation time for the job. Now before you go, tell me your ideas as to furnishings. You will need some things, of course." "Not much," Ted answered quickly. "As I said, I can knock together a bunk and rough table myself. If I could just have a couple of chairs----" Mr. Wharton smiled at the modesty of the request. "Suppose we leave the furnishing until later," said he, turning back to his desk with a gesture of dismissal. "I may drop round there some time to-day while you're working. We can then decide more fully upon what is necessary. You'll find brooms, mops, rags, and water in the barn, you know. Now be off. I'm busy." Away went Ted, only too eager to obey. In no time he was laden with all the paraphernalia he desired. He stopped at Stevens' cottage only long enough to add to his equipment a pail of steaming water and then, staggering under the weight of his burden of implements, made his way to the shack. Once there he threw off his coat, removed his collar and tie, rolled up his sleeves, and went to work. First he cleared the bulk of rubbish from the room and set it outside; then he swept up the floor and mopped it with hot suds; afterwards he washed the windows and rubbed them until they shone. Often he had watched his mother and sisters, who were well trained New England housekeepers, perform similar offices and therefore he knew exactly how such things should be done. It took him a solid morning to render the interior spotless and just as he was pausing to view his handiwork with weary satisfaction Mr. Wharton came striding in at the door. "Mercy on us!" gasped the newcomer with amazement. "You have been busy! Why, I had no idea there were such possibilities in this place. The room is actually a pretty one, isn't it? We shall be able to fix you up snug as a bug in a rug here." He ran his eye quickly about. "If you put your bunk between the windows, you will get plenty of air. You'll need window shades, some comfortable chairs, a bureau, a table----" "I think I can make a table myself," Ted put in timidly. "That is, if I can have some boards." "No, no, no! There are boards enough. But you don't want a makeshift thing like that. If you are going to have books and perhaps read or study, you must have something that will stand solidly on four legs. I may be able to root a table out of some corner. Then there will be bedding----" "I can bring that from home." "All right. We'll count on you to supply that if you are sure you have it to spare. I'll be responsible for the rest." He stopped an instant to glance into the boy's face then added kindly, "So you think you are going to like your new quarters, eh?" "You bet I am!" "That's good! And by the by, I have arranged for you to have your meals with Stevens and his wife. They like you and were glad to take you in. Only you must be prompt and not make them wait for you. Should you prove yourself a bother they might turn you out." "I'll be on hand, sir." "See that you are. They have breakfast at seven, dinner at twelve, and supper at six. Whenever you decide to spend Sunday with your family, or take any meals elsewhere, you must, of course, be thoughtful enough to announce beforehand that you are to be away." "Yes, sir." Ted waited a few moments and then, as Mr. Wharton appeared to be on the point of leaving, he asked with hesitancy: "How--how--much will my meals cost?" An intonation of anxiety rang in the question. "Your meals are our hunt," Mr. Wharton replied instantly. "We shall see to those." "But--but----" "You'll be worth your board to the Fernald estates, never fear, my lad; so put it all out of your mind and don't think of it any more. All is, should we ask of you some little extra service now and then, I am sure you will willingly perform it, won't you?" "Sure!" came with emphatic heartiness. "Then I don't see but everything is settled," the manager declared, as he started back through the grove of pines. "I gave orders up at the toolhouse that you were to have whatever boards, nails, and tools you wanted, so don't hesitate to sail in and hunt up anything you need." "You are mighty kind, sir." "Pooh, pooh. Nonsense! Aren't you improving the Fernald property, I'd like to know?" Mr. Wharton laughed. "This boathouse has been an eyesore for years. We shall be glad enough to have it fixed up and used for something." CHAPTER IV THE FIRST NIGHT IN THE SHACK Throughout the long summer afternoon Ted worked on, fitting up his new quarters. Not only did he make a comfortable bunk for himself such as he had frequently constructed when at logging or sugaring-off camps in Vermont, but having several boards left he built along the racks originally intended for canoes some shelves for the books he meant to bring from home. By late afternoon he had finished all it was possible for him to do and he decided to go to Freeman's Falls and join his own family at supper, and while there collect the possessions he wished to transfer to the shack. Accordingly he washed up and started out. It was a little late when he reached the house and already his father and sisters were at table. "Mercy on us, Ted, what under the sun have you been doing until this time of night?" demanded Mr. Turner. "I should call from seven in the morning until seven at night a pretty long day." "Oh, I haven't been working all this time," laughed the boy. "Or at least, if I have, I have been having the time of my life doing it." Eagerly, and with youthful enthusiasm, he poured out the tale of the day's happenings while the others listened. "So you are starting out housekeeping, are you?" chuckled Mr. Turner, when the narrative was finished. "It certainly ain't a bad idea. Not that we're glad to get rid of you--although I will admit we ain't got the room here that I wish we had. It is the amount of time you'll save and the strength, too, that I'm thinking of. It must be a good three miles up to Aldercliffe and Pine Lea is at least two miles farther. Being on the spot is going to make a lot of difference. But how are you going to get along? What will you do for food? I ain't going to have you eating stuff out of tin cans." "Oh, you needn't worry about me, Dad. Mr. Wharton has arranged for me to take my meals with Mr. and Mrs. Stevens who have a cottage on the place. Stevens is the head farmer, you know." "A pretty penny that will cost you! What does the man think you are--a millionaire?" "Mr. Wharton told me the Fernalds would see to the bill." "Oh! That's another matter," ejaculated Mr. Turner, entirely mollified. "I will say it's pretty decent of Mr. Wharton. Seems to me he is doing a good deal for you." "Yes, he is." "Well, all is you must do your full share in return so he won't lose anything by it." The elder man paused thoughtfully. "Ain't there anything we could do to help out? Perhaps we could donate something toward your furnishings." "Mr. Wharton said if I could supply my own bedding----" "We certainly can do that," put in Ruth quickly. "There is a trunkful of extra comforters and blankets in the back room that I should be thankful enough to ship off somewhere else. And wouldn't you like some curtains? Seems to me they'd make it cosy and homelike. I've a piece of old chintz we've never used. Why not make it into curtains and do away with buying window shades?" "That would be great!" "It would be lots more cheerful," remarked Nancy. "What kind of a bed have you got?" "I've built a wooden bunk-two bunks, in fact--one over the other like the berths in a ship. I thought perhaps sometime Dad might want to come up and visit me; and while I was at it, it was no more work to make two beds than one." Mr. Turner smiled in friendly fashion into his son's eyes. The two were great pals and it pleased him that the lad should have included him in his plans. "Beds like that will do all very well for a night or two; but for a steady thing they will be darned uncomfortable. Cover 'em with pine boughs after a long tramp through the woods and they seem like heaven; but try 'em day after day and they cease to be a joke. Wasn't there a wire spring round here somewhere, Ruth? Seems to me I remember it standing up against something. Why wouldn't that be the very thing? You could fasten it in place and have a bed good as you have at home." "That's a corking idea, Dad!" "I wish we could go up and see the place," Ruth suggested. "I am crazy to know what it looks like. Besides, I want to measure the windows." "Maybe we could run up there to-night," her father replied rising. "It is not late and the Maguires said they would take us out for a little spin in their Ford before dark. They might enjoy riding up to Aldercliffe and be quite willing we should take along the spring bed. Mat is a kind soul and I haven't a doubt he'd be glad to do us a favor. Run down and ask him, Ted; or wait--I'll go myself." The Maguires had the apartment just below the Turner's and Mat, a thrifty and good-humored Irishman, was one of the night watchmen at the Fernald mills. He had a plump little wife, but as there were no children he had been able to save more money than had some of his neighbors, and in consequence had purchased a small car which it was his delight to use for the benefit of his friends. In fact, he often called it the Maguire jitney, and the joke never became threadbare to his simple mind, for every time he made it he laughed as heartily as if he had never heard it before, and so did everybody else. Therefore no sooner had Mr. Turner proposed his plan than Mat was all eagerness to further the project. "Sure I'll take you--as many of you as can pile in, and the spring bed, too! If you don't mind the inconvenience of the luggage, I don't. And tell Ted to bring along anything else he'd like to carry. We can pack you all in and the stuff on top of you. 'Twill be easy enough. Just make ready as soon as you can, so the dark won't catch us." You may be sure the Turners needed no second bidding. Ruth and Nancy scrambled the supper dishes out of the way while Ted and his father hauled the wire spring out, brushed it, and dragged it downstairs. Afterward Ted collected his box of electrical treasures, his books, and clothing. What he would do with all these things he did not stop to inquire. The chance to transfer them was at hand and he seized it with avidity. His belongings might as well be stored in the shack as anywhere else,--better, far better, for the space they left behind would be very welcome to the Turner household. Therefore with many a laugh, the party crowded into the waiting car and set out for Aldercliffe; and when at length they arrived at the house in the pines and Ted unlocked the sliding doors and pushed them wide open, ushering in his guests, what a landholder he felt! "My, but this is a tidy little place!" Maguire ejaculated. "And it's not so little, either. Why, it's a regular palace! Look at the fireplace and the four windows! My eye! And the tier of bunks is neat as a ship's cabin. Bear a hand here with the spring. I'm all of a quaver to see if it fits," cried the man. "I made the bunks regulation size, so I guess there won't be any trouble about that," Ted answered. "The head on the lad!" the Irishman cried. "Ain't he the brainy one, though? You don't catch him wool-gathering! Not he!" Nevertheless he was not content until the spring had been hoisted into place and he saw with his own eyes that it was exactly the proper size. "Could anything be cuter!" observed he with satisfaction. "Now with a good mattress atop of that you will have a bed fit for a king. You'll be comfortable as if you were in a solid gold bedstead, laddie!" "I'm afraid I may be too comfortable," laughed Ted. "What if I should oversleep and not get to breakfast, or to work, on time!" "That would never do," Mr. Turner said promptly. "You must have an alarm clock. 'Twould be but a poor return for Mr. Wharton's kindness were you to come dawdling to work." "I guess you can trust Ted to be on time," put in Ruth soothingly. "He is seldom late--especially to _meals_. Even if he were to be late at other places, I should always be sure he would show up when there was anything to eat." "You bet I would," announced the boy, with a good-humored grin. "I shall have enough chintz for curtains for all your windows," interrupted Nancy, who had been busy taking careful measurements during the conversation. "We'll get some brass rods and make the hangings so they will slip back and forth easily; they will be much nicer than window shades." "Ain't there nothin' I can donate?" inquired Mat Maguire anxiously. "A rag rug, now--why wouldn't that be a good thing? The missus makes 'em by the dozen and our house is full of 'em. We're breakin' our necks mornin', noon, and night on 'em. A couple to lay down here wouldn't be so bad, I'm thinking. You could put one beside your bed and another before the door to wipe your feet on. They'd cheer the room up as well as help keep you warm. Just say the word, sonny, and you shall have 'em." "I'd like them tremendously." The kind-hearted Irishman beamed with pleasure. "Sure, they'll be better out of our house than in it," remarked he, trying to conceal his gratification. "You can try stumbling over 'em a spell instead of me. 'Twill be interesting to see which of us breaks his neck first." It was amazing to see how furniture came pouring in at Ted's bachelor quarters during the next few days. The chintz curtains were finished and hung; the Maguire rugs made their appearance; Mr. Turner produced a shiny alarm clock; and Nancy a roll of colored prints which she had cut from the magazines. "You'll be wanting some pictures," said she. "Tack these up somewhere. They'll brighten up the room and cover the bare walls." Thus it was that day by day the wee shack in the woods became more cheery and homelike. "I've managed to hunt up a few trap's for you," called Mr. Wharton one morning, as he met the boy going to work. "If you want to run over to the cabin now and unlock the door, I'll send a man over with them." Want to! Ted was off in a second, impatient to see what new treasures he was to receive. He had not long to wait, for soon one of the farm trucks came into sight, and the driver began to deposit its contents on the wooden platform which sloped from the door down to the river. As Ted helped the man unload, his eyes shone with delight. Could any gifts be rarer? To be sure the furniture was not new. In fact, some of it was old and even shabby with wear. But the things were all whole, and although they were simple they were serviceable and perhaps looked more in harmony with the old-fashioned curtains and the quaint rugs than if they had come fresh from the shop. There was a chest of drawers; a rocking chair, a leather armchair, and a straight wooden chair; a mirror with frame of faded gilt; a good-sized wooden table; and, best of all, a much scarred, flat-topped desk. Ted had never owned a desk in all his life. Often he had dreamed of sitting behind one when he grew to be a man. But to have it now--here! To have it for his own! How it thrilled him! After the furniture was in place and the teamster had gone, he arranged his few papers and pencils in the desk drawers a score of times, trying them first in one spot and then in another. It was marvelous how much room there was in such an article of furniture. What did men use to fill up such a mighty receptacle, anyway? Stretch his possessions as he would, they only made a scattered showing at the bottom of three of the drawers. He laughed to see them lying there and hear them rattle about when he brought the drawers to with a click. However, it was very splendid to have a desk, whether one had anything to put in it or not, and perhaps in time he would be able to collect more pencils, rulers and blocks of paper. The contrast between not having any room at all for his things and then so much that he did not know what to do with it was amusing. Now at last he was fully equipped to take up residence in his new abode and every instant he could snatch from his duties that day he employed in settling his furniture, making up his bed, filling his water pitcher from the river and completing his final preparations for residence at the boathouse. That night he moved in. Nothing had been omitted that would contribute to his comfort. Mr. Wharton had given him screens for the windows and across the broad door he had tacked a curtain of netting that could be dropped or pushed aside at will. The candlelight glowing from a pair of old brass candlesticks on the shelf above the fireplace contributed rather than took away from the effect and to his surprise the room assumed under the mellow radiance a quality actually æsthetic and beautiful. "I don't believe Aldercliffe or Pine Lea have anything better than this to offer," the boy murmured aloud, as he looked about him with pride. "I'd give anything to have Mr. Wharton see it now that it's done!" Strangely enough, the opportunity to exhibit his kingdom followed on the very heels of his desire, for while he was arranging the last few books he had brought from home on the shelf above his desk he heard a tap at the door. "Are you in bed, son?" called the manager. "I saw your light and just dropped round to see if you had everything you wanted." Rushing to the door, Ted threw it open. "I haven't begun to go to bed yet," returned he. "I've been too excited. How kind of you to come!" "Curiosity! Curiosity!" responded the man hastily. Although Ted knew well that the comment was a libel, he laughed as Mr. Wharton came in, drawing the door together behind him. "By Jove!" burst out the manager, glancing about the room. "You like it?" "Why--what in goodness have you done to the place? I--I--mercy on us!" "You do like it then?" the boy insisted eagerly. "Like it! Why, you've made it into a regular little palace. I'd no idea such a thing was possible. Where did you get your candlesticks and your andirons?" "From home. We have radiators in the apartment and so my sisters had stored them away and were only too glad to have me take them." "Humph! And your curtains came from home, too?" "Yes, sir." "Well, you've missed your calling, is all I can say. You belong in the interior decorating business," asserted Mr. Wharton. "Wait until Mr. Clarence sees this place." Again the elder man looked critically round the interior. "I wouldn't mind living here myself--hanged if I would. The only thing I don't like is those candles. There is a good deal of a draught here and you are too near the pines to risk a fire. Electricity would be safer." Whistling softly to himself, he began to walk thoughtfully about. "I suppose," he presently went on, "it would be a simple enough matter to run wires over here from the barn." "Wouldn't that be bully!" "You'd like it?" "Yes, siree!" The manager took up his hat. "Well, we'll see what can be done," he answered, moving toward the door. But on the threshold he stopped once more and looked about. "I'm going to bring some of the Fernalds over here to see the place," observed he. "For some time Mr. Clarence has been complaining that this shack was a blot on the estate and threatening to pull it down. He'd better have a peep at it now. You may find he'll be taking it away from you." He saw a startled look leap into the boy's eyes. "No, no, sonny! Have no fears. I was only joking," he added. "Nevertheless, the house will certainly be a surprise to anybody who saw it a week ago. I wouldn't have believed such a transformation was possible." Then as he disappeared with his flash-light through the windings of the pine woods he called: "We'll see about that electric wiring. I imagine it won't be much of a job, and I should breathe easier to eliminate those candles, pretty as they are. Until something is done, just be careful not to set yourself and us afire!" With that he was gone. Ted dropped the screen and loitered a moment in the doorway, looking out into the night. Before him stretched the river; so near was it that he could hear the musical lappings of its waters among the tall grasses that bordered the stream. From the ground, matted thickly with pine needles, rose a warm, sun-scorched fragrance heavy with sleep. The boy stretched his arms and yawned. Then he rolled the doors together and began to undress. Suddenly he paused with one shoe in his hand. A thought had come to him. If Mr. Wharton ran the electric wires over to the shack, what was to prevent him from utilizing the current for some of his own contrivances? Why, he could, perhaps, put his wireless instruments into operation and rig up a telephone in his little dwelling. What fun it would be to unearth his treasures from the big wooden box in which they had been so long packed away and set them up here where they would interfere with no one but himself! He hoped with all his heart the manager would continue to be nervous about those candles. CHAPTER V A VISITOR Fervent as this wish was, it was several days before Ted saw Mr. Wharton again and in the meantime the boy began to adapt himself to his new mode of living with a will. His alarm clock got him up in the morning in time for a plunge in the river and after a brisk rub-down he was off to breakfast with the Stevens's, whose cottage was one of a tiny colony of bungalows where lived the chauffeurs, head gardener, electricians, and others who held important positions on the two estates. It did not take many days for Ted to become thoroughly at home in the pretty cement house where he discovered many slight services he could perform for Mrs. Stevens during the scraps of leisure left him after meals. His farm training had rendered him very handy with tools and he was quick to see little things which needed to be done. Moreover, the willingness to help, which from the moment of his advent to Aldercliffe and Pine Lea had made him a favorite with Mr. Wharton and the men, speedily won for him a place with the kindly farmer's wife. Had Ted known it, she had been none too well pleased at the prospect of adopting into her home a ravenous young lad who might, nay, probably would be untidy and troublesome; but she did not dare oppose Mr. Wharton when the plan was suggested. Nevertheless, although she consented, she grumbled not a little to her husband about the inconvenience of the scheme. The money offered her by the manager had been the only redeeming factor in the case. Quite ignorant of these conditions, Ted had made his advent into the house and she soon found to her amazement that the daily coming of her cheery boarder became an event which she anticipated with motherly interest. "He is such a well-spoken boy and so nice to have round," asserted she to Mr. Wharton. "Not a mite of trouble, either. In fact, he's a hundred times handier than my own man, who although he can make a garden thrive can't drive a nail straight to save his life. And there's never any fussing about his food. He eats everything and enjoys it. I believe Stevens and I were getting dreadful pokey all alone here by ourselves. The lad has brightened us up no end. We wouldn't part with him now for anything." Thus it was that Ted Turner made his way. His password was usefulness. He never measured the hours he worked by the clock, never was too busy or too tired to fill in a gap; and although he was popular with everybody, and a favorite with those in authority, he never took advantage of his position to escape toil or obtain privileges. In fact, he worked harder if anything than did the other men, and as soon as his associates saw that the indulgence granted him did not transform him into a pig, they ceased any jealousy they cherished and accorded him their cordial goodwill. For Ted was always modestly respectful toward older persons; and if he knew more about farming and some other things than did a good many of the laborers on the place, he did not push himself forward or boast of his superiority. Consequently when he ventured to say, "I wonder if somebody would help me with this harrow?" he would receive a dozen eager responses, the men never suspecting that Mr. Wharton had given this little chap authority to order them to aid with the harrowing of the field. Instead each workman thought his cooperation a free-will offering and enjoyed giving it. Thus a fortnight passed and no one could have been happier than was Ted Turner on a certain clear June evening. He had finished his Saturday night supper of baked beans and brown bread and after it was over had lingered to feed the Stevens's hens, in order to let Mr. Stevens go early to Freeman's Falls to purchase the Sunday dinner. As a result, it was later than usual when he started out for his camp on the river's brink. The long, busy day was over; he was tired and the prospect of his comfortable bed was very alluring. It was some distance to the shack, and before he was halfway through the pine woods that separated Aldercliffe from Pine Lea darkness had fallen, and he was compelled to move cautiously along the narrow, curving trail. How black the night was! A storm must be brewing, thought he, as he glanced up into the starless heavens. Stumbling over the rough and slippery ground on he went. Then suddenly he rounded a turn in the path and stood arrested with terror. Not more than a rod away, half concealed in the denseness of the sweeping branches rose his little shack, a blaze of light! A wave of consternation turned him cold and two solutions of the mystery immediately flashed into his mind--fire and marauders. Either something had ignited in the interior of the house; or, since it was isolated and had long been known to be vacant, strolling mischief-makers had broken in and were ransacking it. He remembered now that he had left a window open when he had gone off in the morning. Doubtless thieves were at this moment busy appropriating his possessions. Of course it could not be any of the Fernald workmen. They were too friendly and honorable to commit such a dastardly deed. No, it was some one from outside. Was it not possible men had come down the river in a boat from Melton, the village above, and spying the house had made a landing and encamped there for the night? Well, live or die, he must know who his unwelcome guests were. It would be cowardly to leave them in possession of the place and make no attempt to discover their identity. For that invaders were inside the shack he was now certain. It was not a fire. There was neither smoke nor flame. Softly he crept nearer, the thick matting of pine needles muffling his footsteps. But how his heart beat! Suppose a twig should crack beneath his feet and warn the vandals of his approach? And suppose they rushed out, caught him, and--for a moment he halted with fear; then, summoning every particle of courage he possessed, he tiptoed on and contrived to reach one of the windows. There he halted, staring, his knees weak from surging reaction. Instead of the company of bandits his mind had pictured, there in the rocker sat Mr. Wharton and opposite him, in the great leather armchair, was Mr. Clarence Fernald. The latter fact would have been astounding enough. But the marvel did not cease there. The light suffusing the small room came from no flickering candles but glowed steadily from two strong, unblinking electric lights, one of which had been connected with a low lamp on his desk, and the other with a fixture in the ceiling. Ted could scarcely believe his eyes. All day, during his absence, electricians must have been busy. How carefully they had guarded their secret. Why, he had talked with Tim Toyer that very morning on his way to work and Tim had breathed no word, although he was the head electrician and had charge of the dynamo which generated the current both for Aldercliffe and Pine Lea. The Fernalds had never depended on Freeman's Falls for their electricity; on the contrary, they maintained a small plant of their own and used the power for a score of purposes on the two estates. Evidently either Mr. Wharton or Mr. Clarence Fernald himself must have given the order which had with such Aladdin-like magic been so promptly and mysteriously fulfilled. It certainly was kind of them to do this and Ted determined they should not find him wanting in gratitude. Pocketing his shyness, he opened the door and stepped into the room. "Well, youngster, I thought it was about time the host made his appearance," exclaimed Mr. Wharton. "We could not have waited much longer. Mr. Fernald, this is Ted Turner, the lad I have been telling you about." Ted waited. The mill-owner nodded, let his eye travel over the boy's flushed face, and then, as if satisfied by what he saw there, he put out his hand. "I have been hearing very excellent reports of you, Turner," said he, "and I wished to investigate for myself the quarters they have given you to live in. You've made a mighty shipshape little den of this place." "It didn't need very much done to it," protested Ted, blushing under the fixed gaze of the great man. "I just cleaned it up and arranged the furniture. Mr. Wharton was kind enough to give me most of it." "I can't claim any thanks," laughed the manager. "The traps I gave you were all cast-offs and not in use. It is what you have done with them that is the marvel." "You certainly have turned your donations to good purpose," Mr. Fernald observed. "I've been noticing your books in your absence and see that most of them are textbooks on electricity. I judge you are interested in that sort of thing." "Yes, sir, I am." "Humph!" The financier drummed reflectively on the arm of his chair. "How did you happen to go into that?" he asked presently. "I have been studying it at school. My father is letting me go through the high school--at least he hopes to let me finish my course there. I have been two years already. That is why I am working during the summer." "I see. And so you have been taking up electricity at school, eh?" "Yes, sir. I really am taking a business course. The science work in the laboratory is an extra that I just run in because I like it. My father wanted me to fit myself for business. He thought it would be better for me," explained Ted. "But you prefer the science?" "I am afraid I do, sir," smiled Ted, with ingratiating honesty. "But I don't mean to let it interfere with my regular work. I try to remember it is only a side issue." Mr. Clarence Fernald did not answer and during his interval of silence Ted fell to speculating on what he was thinking. Probably the magnate was disapproving of his still going to school and was saying to himself how much better it would have been had he been put into the mill and trained up there instead of having his head stuffed with stenography and electrical knowledge. "What did you do in electricity?" the elder man asked at length. "Oh, I fussed around some with telephones, wireless, and telegraph instruments." Mr. Fernald smiled. "Did you get where you could take messages?" inquired he with real interest. "By telegraph?" The financier nodded. "I did a little at it," replied Ted. "Of course I was slow." "And what about wireless?" "I got on better with that. I rigged up a small receiving station at home but when the war came I had to take it down." "So that outfit was yours, was it?" commented Mr. Fernald. "I noticed it one day when I was in the village. What luck did you have with it?" "Oh, I contrived to pick up messages within a short radius. My outfit wasn't very powerful." "I suppose not. And the telephone?" They saw an eager light leap into the lad's eyes. "I've worked more at that than anything else," replied he. "You see one of the instruments at the school gave out and they set me to tinkering at it. In that way I got tremendously interested in it. Afterward some of us fellows did some experimenting and managed to concoct a crude one in the laboratory. It wasn't much of a telephone but we finally got it to work." "They tell me you are a good farmer as well as an electrician," Mr. Fernald said. "Oh, I was brought up on a farm, sir." The great man rose. "Well, mind you don't let your electricity make you forget your farming," cautioned he, not unkindly. "We need you right where you are. Still I will own electricity is a pleasant pastime. You will have a current to work with now whenever you want to play with it. Just be sure you don't get a short circuit and blow out my dynamo." "Do--do--you really mean I may use the current for experiments?" demanded Ted. Whether Mr. Fernald had made his remarks in jest or expected them to be taken seriously was not apparent; and if he were surprised at having the boy catch him up and hold him to account, he at least displayed not a trace of being taken unawares. For only an instant was he thoughtful, and that was while he paused and studied the countenance of the lad before him. "Why, I don't know that I see any harm in your using the current for reasonable purposes," he answered slowly, after an interval of meditation. "You understand the dangers of running too many volts through your body and of crossing wires, don't you?" "Oh, yes, sir," laughed Ted. "I must confess I should not trust every boy with such a plaything," continued the magnate, "but you seem to have a good head on your shoulders and I guess we can take a chance on you." He moved silently across the room but on the threshold he turned and added with self-conscious hesitancy, "By the way my--my--son, Mr. Laurie, chances to be interested in electricity, too. Perhaps some day he might drop in here and have a talk about this sort of thing." "I wish he would." With a quiet glance the father seemed to thank the lad for his simple and natural reply. Both of them knew but too well that such an event could never be a casual happening, and that if poor Mr. Laurie ever _dropped in_ at the shack it would be only when he was brought there, either in his wheel-chair or in the arms of some of the servants from Pine Lea. Nevertheless it was obvious that Mr. Fernald appreciated the manner in which Ted ignored these facts and suppressed his surprise at the unusual suggestion. Had Mr. Laurie's dropping in been an ordinary occurrence no one could have treated it with less ceremony than did Ted. An echo of the gratitude the capitalist felt lingered in his voice when he said good night. It was both gentle and husky with emotion and the lad fell asleep marvelling that the men employed at the mills should assert that the Fernalds were frigid and snobby. CHAPTER VI MORE GUESTS When with shining eyes Ted told his father about Mr. Fernald's visit to the shack, Mr. Turner simply shrugged his shoulders and smiled indulgently. "Likely Mr. Clarence's curiosity got the better of him," said he, "and he wanted to look your place over and see that it warn't too good; or mebbe he just happened to be going by. He never would have taken the trouble to go that far out of his way if he hadn't had something up his sleeve. When men like him are too pleasant, I'm afraid of 'em. And as for Mr. Laurie _dropping in_--why, his father and grandfather would no more let him associate with folks like us than they'd let him jump headfirst into the river. We ain't good enough for the Fernalds. Probably almost nobody on earth is. And when it comes to Mr. Laurie, why, in their opinion the boy doesn't live who is fit to sit in the same room with him." Ted's bright face clouded with disappointment. "I never thought of Mr. Laurie feeling like that," answered he. "Oh, I ain't saying Mr. Laurie himself is so high and mighty. He ain't. The poor chap has nothing to be high and mighty about and he knows it. Anybody who is as dependent on others as he is can't afford to tilt his nose up in the air and put on lugs. For all I know to the contrary he may be simple as a baby. It's his folks that think he's the king-pin and keep him in cotton wool." Mr. Turner paused, his lip curling with scorn. "You'll never see Mr. Laurie at your shack, mark my words. His people would not let him come even if he wanted to." The light of eagerness in his son's countenance died entirely. "I suppose you're right," admitted he slowly and with evident reluctance. Although he would not have confessed it, he had been anticipating, far more than he would have been willing to own, the coming of Mr. Laurie. Over and over again he had lived in imagination his meeting with this fairy prince whose grave, wistful face and pleasant smile had so strongly attracted him. He had speculated to himself as to what the other boy was like and had coveted the chance to speak to him, never realizing that they were not on an equal plane. Mr. Fernald's suggestion of Laurie visiting the shack seemed the most natural thing in the world, and immediately after it had been made Ted's fancy had run riot, and he had leaped beyond the first formal preliminaries to a time when he and Laurie Fernald would really know one another, even come to be genuine friends, perhaps. What sport two lads, interested in the same things, could have together! Ted had few companions who followed the bent of thought that he did. The fellows he knew either at school or in the town were ready enough to play football and baseball but almost none of them, for example, wanted to sacrifice a pleasant Saturday to constructing a wireless outfit. One or two of them, it is true, had begun the job but they soon tired of it and either sat down to watch him work or had deserted him altogether. The only congenial companion he had been able to count on had been the young assistant in the laboratory at school who, although he was not at all aged, was nevertheless years older than Ted. But with the mention of Mr. Laurie myriad dreams had flashed into his mind. Here was no prim old scholar but a lad like himself, who probably did not know much more about electrical matters than he. You wouldn't feel ashamed to admit your ignorance before such a person, or own that you either did not know, or did not understand. You could blunder along with such a companion to your heart's content. Such had been his belief until now, with a dozen words, Ted saw his father shatter the illusion. No, of course Mr. Laurie would never come to the shack. It had been absurd to think it for a moment. And even if he did, it would only be as a lofty and unapproachable spectator. Mr. Fernald's words were a subtly designed flattery intended to put him in good humor because he wanted something of him. What could it be? Perhaps he meant to oust him out of the boathouse and rebuild it, or possibly tear it down; or maybe he had taken a fancy to use it as it was and desired to be rid of Ted in some sort of pleasant fashion. Unquestionably the building belonged to Mr. Fernald and if he chose to reclaim it he had a perfect right to do so. Poor Ted! With a crash his air castles tumbled about his ears and the ecstasy of his mood gave way to apprehension and unhappiness. Each day he waited, expecting to hear through Mr. Wharton that Mr. Clarence Fernald had decided to use the shack for other purposes. Time slipped along, however, and no such tidings came. In the meanwhile Mr. Wharton made no further mention of the Fernalds and gradually Ted's fears calmed down sufficiently for him to gain confidence enough to unpack his boxes of wire, his tools, and instruments. Nevertheless, in spite of this, his first enthusiasm had seeped away and he did not attempt to go farther than to take the things out and look at them. Before his father had withered his ambitions by his pessimism, a score of ideas had danced through his brain. He had thought of running a buzzer over to the Stevens's bungalow in order that Mrs. Stevens might ring for him when she wanted him; and he had thought of connecting Mr. Wharton's office with the shack by telephone. He felt sure he could do both these things and would have liked nothing better than try them. But now what was the use? If a little later on Mr. Fernald intended to take the shack away from him, it would be foolish to waste toil and material for nothing. For the present, at least, he much better hold off and see what happened. Yet notwithstanding this resolve, he did continue to improve the appearance of the boathouse. Just why, he could not have told. Perhaps it was a vent for his disquietude. At any rate, having some scraps of board left and hearing the gardener say there were more geraniums in the greenhouse than he knew what to do with, Ted made some windowboxes for the Stevens's and himself, painted them green, and filled them with flowering plants. They really were very pretty and added a surprising touch of beauty to the dull, weather-stained little dwelling in the woods. Mr. Wharton was delighted and said so frankly. "Your camp looks as attractive as a teahouse," said he. "You have no idea how gay the red flowers look among these dark pine trees. How came you to think of window-boxes?" "Oh, I don't know," was Ted's reply. "The bits of board suggested it, I guess. Then Collins said the greenhouses were overstocked, and he seemed only too glad to get rid of his plants." "I'll bet he was," responded Mr. Wharton. "If there is anything he hates, it is to raise plants and not have them used. He always has to start more slips than he needs in case some of them do not root; when they do, he is swamped. Evidently you have helped him solve his problem for no sooner did the owners of the other bungalows see Stevens's boxes than everybody wanted them. They all are pestering the carpenter for boards. It made old Mr. Fernald chuckle, for he likes flowers and is delighted to have the cottages on the place made attractive. He asked who started the notion; and when I told him it was you he said he had heard about you and wanted to see you some time." This time Ted was less thrilled by the remark than he would have been a few days before. A faint degree of his father's scepticism had crept into him and the only reply he vouchsafed was a polite smile. It was absurd to fancy for an instant that the senior member of the Fernald company, the head of the firm, the owner of Aldercliffe, the great and rich Mr. Lawrence Fernald, would ever trouble himself to hunt up a boy who worked on the place. Ridiculous! Yet it was on the very day that he made these positive and scornful assertions to himself that he found this same mighty Mr. Lawrence Fernald on his doorstep. It was early Saturday afternoon, a time Ted always had for a holiday. He had not been to see his family for some time and he had made up his mind to start out directly after luncheon and go to Freeman's Falls, where he would, perhaps, remain overnight. Therefore he came swinging through the trees, latchkey in hand, and hurriedly rounding the corner of the shack, he almost jostled into the river Mr. Lawrence Fernald who was loitering on the platform before the door. "I beg your pardon, sir!" he gasped. "I did not know any one was here." "Nor did I, young man," replied the ruffled millionaire. "You came like a thief in the night." "It is the pine needles, sir," explained the boy simply. "Unless you happen to step on a twig that cracks you don't hear a sound." The directness of the lad evidently pleased the elder man for he answered more kindly: "It is quiet here, isn't it? I did not know there was a spot within a radius of five miles that was so still. I was almost imagining myself in the heart of the Maine woods before you came." "I never was in the Maine woods," ventured Ted timidly, "but if it is finer than this I'd like to see it." "You like your quarters then?" "Indeed I do, sir." "And you're not afraid to stay way off here by yourself?" "Oh, no!" Mr. Fernald peered over the top of his glasses at the boy before him. "Would you--would you care to come inside the shack?" Ted inquired after an interval of silence, during which Mr. Fernald had not taken his eyes from his face. "It is very cosy indoors--at least I think so." "Since I am here I suppose I might just glance into the house," was the capitalist's rather magnificent retort. "I don't often get around to this part of the estate. To-day I followed the river and came farther away from Aldercliffe than I intended. When I got to this point the sun was so pleasant here on the float that I lingered." Nodding, Ted fitted the key into the padlock, turned it, and rolled the doors apart, allowing Mr. Fernald to pass within. The mill owner was a large man and as he stalked about, peering at the fireplace with its andirons of wrought metal, examining the chintz hangings, and casting his eye over the books on the shelf, he seemed to fill the entire room. Then suddenly, having completed his circuit of the interior, he failed to bow himself out as Ted expected and instead dropped into the big leather armchair and proceeded to draw out a cigar. "I suppose you don't mind if I smoke," said he, at the same instant lighting a match. "Oh, no. Dad always smokes," replied the boy. "Your father is in our shipping room, they tell me." "Yes, sir." "Where did you live before you came here?" "Vermont." "Vermont, eh?" commented the older man with interest. "I was born in Vermont." "Were you?" Ted ejaculated. "I didn't know that." "Yes, I was born in Vermont," mused Mr. Fernald slowly. "Born on a farm, as you no doubt were, and helped with the haying, milking, and other chores." "There were plenty of them," put in the boy, forgetting for the moment whom he was addressing. "That's right!" was the instant and hearty response. "There was precious little time left afterward for playing marbles or flying kites." The lad standing opposite chuckled understandingly and the capitalist continued to puff at his cigar. "Spring was the best time," observed he after a moment, "to steal off after the plowing and planting were done and wade up some brook----" "Where the water foamed over the rocks," interrupted the boy, with sparkling eyes. "We had a brook behind our house. There were great flat rocks in it and further up in the woods some fine, deep trout holes. All you had to do was to toss a line in there and the next you knew----" "Something would jump for it," cried the millionaire, breaking in turn into the conversation and rubbing his hands. "I remember hauling a two-pounder out of just such a spot. Jove, but he was a fighter! I can see him now, thrashing about in the water. I wasn't equipped with a rod of split bamboo, a reel, and scores of flies in those days. A hook, a worm, and a stick you'd cut yourself was your outfit. Nevertheless I managed to land my fish for all that." Lured by the subject Ted came nearer. "Any pickerel holes where you lived?" inquired Mr. Fernald boyishly. "You bet there were!" replied the lad. "We had a black, scraggy pond two miles away, dotted with stumps and rotting tree trunks. About sundown we fellows would steal a leaky old punt anchored there and pole along the water's edge until we reached a place where the water was deep, and then we'd toss a line in among the roots. It wasn't long before there would be something doing," concluded he, with a merry laugh. "How gamey those fish are!" observed Mr. Fernald reminiscently. "And bass are sporty, too." "I'd rather fish for bass than anything else!" asserted Ted. "Ever tried landlocked salmon?" "N--o. We didn't get those." "That's what you get in Maine and New Brunswick," explained Mr. Fernald. "I don't know, though, that they are any more fun to land than a good, spirited bass. I often think that all these fashionable camps with their guides, and canoes, and fishing tackles of the latest variety can't touch a Vermont brook just after the ice has thawed. I'd give all I own to live one of those days of my boyhood over again!" "So would I!" echoed Ted. "Pooh, nonsense!" objected Mr. Fernald. "You are young and will probably scramble over the rocks for years to come. But I'm an old chap, too stiff in the joints now to wade a brook. Still it is a pleasure to go back to it in your mind." His face became grave, then lighted with a quick smile. "I'll wager the material for those curtains of yours never was bought round here. Didn't that come from Vermont? And the andirons, too?" "Yes, sir." "Ah, I knew it! We had some of that old shiny chintz at home for curtains round my mother's four-poster bed." He rose and began to pace the room thoughtfully. "Some day my son is going to bring his boy over here," he remarked. "He is interested in electricity and knows quite a bit about it. I was always attracted to science when I was a youngster. I----" He got no further for there was a stir outside, a sound of voices, and a snapping of dry twigs; and as Ted glanced through the broad frame of the doorway he saw to his amazement Mr. Clarence Fernald wheel up the incline just outside a rubber-tired chair in which sat Laurie. "I declare if here isn't my grandson now!" exclaimed Mr. Fernald, bustling toward the entrance of the shack. Ah, it needed no great perception on Ted's part to interpret the pride, affection, and eagerness of the words; in the tones of the elder man's voice rang echoes of adoration, hope, fear, and disappointment. The millowner, however, speedily put them all to rout by crying heartily: "Well, well! This seems to be a Fernald reunion!" "Grandfather! Are you here?" cried the boy in the chair, extending his thin hand with the vivid smile Ted so well remembered. "Indeed I am! Young Turner and I were just speaking of you. I told him you were coming to see him some day." Laurie glanced toward Ted. "It is nice of you to let me come and visit you," he said, with easy friendliness. "What a pretty place you have and how gay the flowers are! And the river is beautiful! Our view of it from Pine Lea is not half so lovely as this." "Perhaps you might like to sit here on the platform for a while," suggested Ted, coming forward rather shyly and smiling down into the lad's eyes. Laurie returned the smile with delightful candor. "You're Ted Turner, aren't you?" inquired he. "They've told me about you and how many things you can do. I could not rest until I had seen the shack. Besides, Dad says you have some books on electricity; I want to see them. And I've brought you some of mine. They're in a package somewhere under my feet." "That was mighty kind of you," answered Ted, as he stooped to secure the volumes. "Not a bit. My tutor, Mr. Hazen, got them for me and some of them are corking--not at all dry and stupid as books often are. If you haven't seen them already, I know you'll like them." How easily and naturally it all came about! Before they knew it, Mr. Fernald was talking, Mr. Clarence Fernald was talking, Laurie was talking, and Ted himself was talking. Sitting there so idly in the sunshine they joked, told stories, and watched the river as it crept lazily along, reflecting on its smooth surface the gold and azure of the June day. During the pauses they listened to the whispering music of the pines and drank in their sleepy fragrance. More than once Ted pinched himself to make certain that he was really awake. It all seemed so unbelievable; and yet, withal, there was something so simple and suitable about it. By and by Mr. Clarence rose, stretched his arms, and began boyishly to skip stones across the stream; then Ted tried his skill; and presently, not to be outdone by the others, Grandfather Fernald cast aside his dignity and peeling off his coat joined in the sport. How Laurie laughed, and how he clapped his hands when one of his grandfather's pebbles skimmed the surface of the water six times before it disappeared amid a series of widening ripples. After this they all were simply boys together, calling, shouting, and jesting with one another in good-humored rivalry. What use was it then ever again to attempt to be austere and unapproachable Fernalds? No use in the world! Although Mr. Fernald, senior, mopped his brow and slipped back into his coat with a shadow of surprise when he came to and realized what he had been doing, he did not seem to mind greatly having lapsed from seventy years to seven. The fact that he had furnished Laurie with amusement was worth a certain loss of dignity. Ah, it would have taken an outsider days, weeks, months, perhaps years to have broken through the conventionalities and beheld the Fernalds as Ted saw them that day. It was the magic of the sunshine, the sparkle of the creeping river, the mysterious spell of the pines that had wrought the enchantment. Perhaps, too, the memory of his Vermont boyhood had risen freshly to Grandfather Fernald's mind. When the shadows lengthened and the glint of gold faded from the river, they went indoors and Mr. Laurie was wheeled about that he might inspect every corner of the little house of which he had heard so much. This he did with the keenest delight and it was only after both his father and his grandfather had promised to bring him again that he could be persuaded to be carried back to Pine Lea. As he disappeared among the windings of the trees, he waved his hand to Ted and called: "I'll see you some day next week, Ted. Mr. Hazen, my tutor, shall bring me round here some afternoon when you have finished work. I suppose you don't get through much before five, do you?" "No, I don't." "Oh, any time you want to see Ted I guess he can be let off early," cried both Mr. Fernald and Mr. Clarence in one breath. Then as Mr. Clarence pushed the wheel-chair farther into the dusk of the pines, Mr. Fernald turned toward Ted and added in an undertone: "It's done the lad good to come. I haven't seen him in such high spirits for days. We'll fix things up with Wharton so that whenever he fancies to come here you can be on hand. The poor boy hasn't many pleasures and he sees few persons of his own age." CHAPTER VII MR. LAURIE The visits of Laurie during the following two weeks became very frequent; and such pleasure did they afford him that orders were issued for Ted Turner to knock off work each day at four o'clock and return to the shack, where almost invariably he found his new acquaintance awaiting him. It was long since Laurie Fernald had had a person of his own age to talk with. In fact, he had never before seen a lad whose friendship he desired. Most boys were so well and strong that they had no conception of what it meant not to be so, and their very robustness and vitality overwhelmed a personality as sensitively attuned as was that of Laurie Fernald. He shrank from their pity, their blundering sympathy, their patronage. But in Ted Turner he immediately felt he had nothing to dread. He might have been a Marathon athlete, so far as any hint to the contrary went. Ted appeared never to notice his disability or to be conscious of any difference in their physical equipment; and when, as sometimes happened, he stooped to arrange a pillow, or lift the wheel-chair over the threshold, he did it so gently and yet in such a matter-of-fact manner that one scarcely noticed it. They were simply eager, alert, bubbling, interested boys together, and as the effect of the friendship showed itself in Laurie's shining eyes, all the Fernalds encouraged it. "Why, that young Turner is doing Laurie more good than a dozen doctors!" asserted Grandfather Fernald. "If he did no work on the farm at all, Ted would be worth his wages. Money can't pay for what he has done already. I'm afraid Laurie has been missing young friends more than we realized. He never complains and perhaps we did not suspect how lonely he was." Mr. Clarence nodded. "Older people are pretty stupid about children sometimes, I guess," said he sadly. "Well, he has Ted Turner now and certainly he is a splendid boy for him to be with. Laurie's tutor, Mr. Hazen, likes him tremendously. What a blessing it is that Wharton stumbled on him and brought him up here. Had we searched the countryside I doubt if we could have found any one Laurie would have liked so much. He doesn't care especially for strangers." With the Fernald's sanction behind the friendship, and both Laurie's tutor and his doctor urging it on, you may be sure it thrived vigorously. The boys were naturally companionable and now, with every barrier out of the way, and every fostering influence provided, the two soon found themselves on terms of genuine affection. If Laurie went for a motor ride Saturday afternoon, Ted must go, too; if he had a new book, Ted must share it, and when he was not as well as usual, or it was too stormy for him to be carried to the shack, nothing would do but Ted Turner must be summoned to Pine Lea to brighten the dreariness of the day. Soon the servants came to know the newcomer and understand that he was a privileged person in the household. Laurie's mother, a pretty Southern woman, welcomed him kindly and it was not long before the two were united in a deep and affectionate conspiracy which placed them on terms of the greatest intimacy. "Laurie isn't quite so well this afternoon, Ted," Mrs. Fernald would say. "Don't let him get too excited or talk too much." Or sometimes it was, "Laurie had a bad night last night and is dreadfully discouraged to-day. Do try and cheer him up." Not infrequently Mr. Hazen would voice an appeal: "I haven't been able to coax Laurie to touch his French lesson this morning. Don't you want to see if you can't get him started on it? He'll do anything for you." And when Ted did succeed in getting the lesson learned, and not only that but actually made an amusing game out of it, how grateful Mr. Hazen was! For with all his sweetness Laurie Fernald had a stubborn streak in his nature which the volume of attention he had received had only served to accentuate. He was not really spoiled but there were times when he would do as he pleased, whether or no; and when such a mood came to the surface, no one but Ted Turner seemed to have any power against it. Therefore, when it occasionally chanced that Laurie refused to see the doctor, or would not take his medicine, or insisted on getting up when told to lie in bed, Ted was made an ally and urged to promote the thing that made for the invalid's health and well-being. After being admitted into the family circle on such confidential terms, it followed that absolute equality was accorded Ted and he came and went freely, both at Aldercliffe and Pine Lea. He read with Laurie, lunched with him, followed his lessons; and listened to his plans, his pleasures, and his disappointments. Perhaps, too, Laurie Fernald liked and respected him the more that he had duties to perform and therefore was not always free to come at his beck and call as did everybody else. "I shan't be able to get round to see you to-day, old chap," Ted would explain over the telephone. "There is a second crop of peas to plant in the further lot and as Mr. Stevens is short of men, I'm going to duff in and help, even if it isn't my job. Of course I want to do my bit when they are in a pinch. I'll see you to-morrow." And although Laurie grumbled a good deal, he recognized the present need, and becoming interested in the matter in spite of himself, wished to hear the following day all about the planting. That he should inquire greatly delighted both his father and his grandfather who had always been anxious that he should come into touch with the management of the estates. Often they had tried to talk to him of crops and gardens, plowing and planting, but to the subject the heir had lent merely a deaf ear. Now with Ted Turner's advent had come a new influence, the testimony of one who was practically interested in agricultural problems and thought farming anything but dull. The boy was genuinely eager that the work of the men should be a success and therefore when he hoped for fair weather for the haying and it seemed to make a real difference to him whether it was pleasant or not, how could Laurie help being eager that it should not rain until the fields were mowed and the crop garnered into the great barns? Or when Ted was worrying about the pests that invaded the garden, one wouldn't have been a true friend not to ask how the warfare was progressing. Before Laurie knew it, he had learned much about the affairs of the estates and had become awake to the obstacles good farmers encounter in their strife with soil and weather conditions. As a result his outlook broadened, he became less introspective and more alive to the concerns of those about him; and he gained a new respect for his father's and grandfather's employees. One had much less time to be depressed and discouraged when one had so many things to think of. Sometimes Ted brought in seeds and showed them; and afterward a slender plant that had sprouted; and then Mr. Hazen would join in and tell the two boys of other plants,--strange ones that grew in novel ways. Or perhaps the talk led to the chemicals the gardeners were mixing with the soil and wandered off into science. Every topic seemed to reach so far and led into such fascinating mazes of knowledge! What a surprising place the world was! Of course, had the Fernalds so desired they could have relieved Ted of all his farming duties, and indeed they were sorely tempted at times to do so; but when they saw how much better it was to keep the boy's visits a novelty instead of making of them a commonplace event, and sensed how much knowledge he was bringing into the invalid's room, they decided to let matters progress as they were going. They did, however, arrange occasional holidays for the lad and many a jolly outing did Ted have in consequence. Had they displayed less wisdom they might have wrecked the friendship altogether. As it was they strengthened it daily and the little shack among the pines became to both Ted and to Laurie the most loved spot in the world. Frequently the servants from Pine Lea surprised the boys by bringing them their luncheon there; and sometimes Mrs. Fernald herself came hither with her tea-basket, and the entire family sat about before the great stone fireplace and enjoyed a picnic supper. It was after one of these camping teas that Mr. Clarence Fernald bought for Laurie a comfortable Adirondack canoe luxuriously fitted up with cushions. The stream before the boathouse was broad and contained little or no current except down toward Pine Lea, where it narrowed into rapids that swept over the dam at Freeman's Falls. Therefore if one kept along the edges of the upper part of the river, there was no danger and the canoe afforded a delightful recreation. Both the elder Fernalds and Mr. Hazen rowed well and Ted pulled an exceptionally strong oar for a boy of his years. Hence they took turns at propelling the boat and soon Laurie was as much at home on the pillows in the stern as he was in his wheel-chair. He greatly enjoyed the smooth, jarless motion of the craft; and often, even when it was anchored at the float, he liked to be lifted into it and lie there rocking with the wash of the river. It made a change which he declared rested him, and it was through this simple and apparently harmless pleasure that a terrible catastrophe took place. On a fine warm afternoon Mr. Hazen and Laurie went over to the shack to meet Ted who usually returned from work shortly after four o'clock. The door of the little camp was wide open when they arrived but their host was nowhere to be seen. This circumstance did not trouble them, however, for on the days when Laurie was expected Ted always left the boathouse unlocked. What did disconcert them and make Laurie impatient was to discover that through some error in reckoning they were almost an hour too early. "Our clocks must have been ahead of time," fretted the boy. "We shall have to hang round here the deuce of a while." "Wouldn't you like me to wheel you back through the grove?" questioned the tutor. "Oh, there's no use in that. Suppose you get out the pillows and help me into the boat. I'll lie there a while and rest." "All right." With a ready smile Mr. Hazen plunged into the shack and soon returned laden with the crimson cushions, which he arranged in the stern of the canoe with greatest care. Afterward he picked Laurie up in his arms as if he had been a feather and carried him to the boat. "How's that?" he asked, when the invalid was settled. "Fine! Great, thanks! You're a wonder with pillows, Mr. Hazen; you always get them just right," replied the lad. "Now if I only had my book----" "I could go and get it." "Oh, no. Don't bother. Ted will be here before long, won't he? What time is it?" "About half-past three." "Only half-past three! Great Scott! I thought it must be nearly four by this time. Then I have quite a while to wait, don't I? I don't see why you got me over here so early." "I don't either," returned Mr. Hazen pleasantly. "I'm afraid my watch must have been wrong." Laurie moved restlessly on the pillows. He had passed a wretched night and was worn and nervous in consequence. "I guess perhaps you'd better run back to the house for my book," remarked he presently. "I shall be having a fit of the blues if I have to hang round here so long with nothing to do." "I'm perfectly willing to go back," Mr. Hazen said. "But are you sure----" "Oh, I'm all right," cut in the boy sharply. "I guess I can sit in a boat by myself for a little while." "Still, I'm not certain that I ought to----" "Leave me? Nonsense! What do you think I am, Hazen? A baby? What on earth is going to happen to me, I'd like to know?" "Nevertheless I don't like to----" "Oh, do stop arguing. It makes me tired. Cut along and get the book, can't you? Why waste all this time fussing?" burst out the invalid fretfully. "How am I ever going to get well, or think I am well, if you keep reminding me every minute that I am a helpless wreck? It is enough to discourage anybody. Why can't you treat me like other people? If you chose to sit in a boat alone for half an hour nobody'd throw a fit. Why can't I?" "I suppose you can," retorted the tutor unwillingly. "Only you know we never do----" "Leave me? Don't I know it? The way people tag at my heels drives me almost crazy sometimes. You wouldn't like to have some one dogging your footsteps from morning until night, would you?" "I'm afraid I shouldn't," admitted Mr. Hazen. For an interval Laurie was silent; then he glanced up with one of his swift, appealing smiles. "There, there, Mr. Hazen!" he said with winning sincerity. "Forgive me. I didn't mean to be cross. I do get so fiendishly impatient sometimes. How you can keep on being so kind to me I don't see. Do please go and get the book, like a good chap. It's on the chair in my room or else on the library table. You'll find it somewhere. 'Treasure Island,' you know. I had to leave it in the middle of a most exciting chapter and I am crazy to know how it came out." Reluctantly Mr. Hazen moved away. It was very hard to resist Laurie Fernald when he was in his present mood; besides, the young tutor was genuinely fond of his charge and would far rather gratify his wishes than refuse him anything. Therefore he hurried off through the grove, resolving to return as fast as ever he could. In the meantime Laurie threw his head back on the pillows and looked up at the sky. How blue it was and how lazily the clouds drifted by! Was any spot on earth so still as this? Why, you could not hear a sound! He yawned and closed his eyes, the fatigue of his sleepless night overcoming him. Soon he was lost in dreams. * * * * * He never could tell just what it was that aroused him; perhaps it was a premonition of danger, perhaps the rocking of the boat. At any rate he was suddenly broad awake to find himself drifting out into the middle of the stream. In some way the boat must have become unfastened and the rising breeze carried it away from shore. Not that it mattered very much now. The thing that was of consequence was that he was helplessly drifting down the river with no means of staying his progress. Soon he would be caught in the swirl of the current and then there would be no help for him. What was he to do? Must he lie there and be borne along until he was at last carried over the dam at his father's mills? He saw no escape from such a fate! There was not a soul in sight. The banks of the river were entirely deserted, for the workmen were far away, toiling in the fields and gardens, and they could not hear him even were he to shout his loudest. As for Mr. Hazen, he was probably still at Pine Lea searching for the book and wouldn't be back for some time. The boy's heart sank and he quivered with fear. Must he be drowned there all alone? Was there no one to aid him? Thoroughly terrified, he began to scream. But his screams only reëchoed from the silent river banks. No one heard and no one came. He was in the current of the stream now and moving rapidly along. Faster and faster he went. Yes, he was going to be swept on to Freeman's Falls, going to be carried over the dam and submerged beneath that hideous roar of water that foamed down on the jagged rocks in a boiling torrent of noise and spray. Nobody would know his plight until the catastrophe was over; and even should any of the mill hands catch sight of his frail craft as it sped past it would be too late for them to help him. Before a boat could be launched and rescuers summoned he would be over the falls. Yes, he was going to die, _to die_! Again he screamed, this time less with a thought of calling for help than as a protest against the fate awaiting him. To his surprise he heard an answering shout and a second later saw Ted Turner dash through the pines, pause on the shore, and scan the stream. Another instant and the boy had thrown off his coat and shoes and was in the water, swimming toward the boat with quick, overhand strokes. [Illustration: He heard an answering shout and a second later saw Ted Turner dash through the pines. _Page_ 88.] "Keep perfectly still, Laurie!" he panted. "You're all right. Just don't get fussed." Yet cheering as were the words, they could not conceal the fact that Ted was frightened, terribly frightened. The canoe gained headway with the increasing current. It seemed now to leap along. And in just the proportion that its progress was accelerated, the speed of the pursuer lessened. It seemed as if Ted would never overtake his prize. How they raced one another, the bobbing craft and the breathless boy! Ted Turner was a strong swimmer but the canoe with its solitary occupant was so light that it shot over the surface of the water like a feather. Was the contest to be a losing one, after all? Laurie, looking back at the wake of the boat, saw Ted's arm move slower and slower and suddenly a wave of realization of the other's danger came upon him. They might both be drowned,--two of them instead of one! "Give it up, old man!" he called bravely. "Don't try any more. You may go down yourself and I should have to die with that misery on my soul. You've done your best. It's all right. Just let me go! I'm not afraid." There was no answer from the swimmer but he did not stop. On the contrary, he kept stubbornly on, plowing with mechanical persistence through the water. Then at length he, too, was in the current and was gaining surely and speedily. Presently he was only a length away from the boat--he was nearer--nearer! His arm touched the stern and Laurie Fernald caught his hand in a firm grip. There he hung, breathing heavily. "I've simply got to stop a second or two and get my wind," said he. "Then we'll start back." "Ted!" "There are no oars, of course, but I can tie the rope around my body or perhaps catch it between my teeth. The canoe isn't heavy, you know. After we get out of the current and into quiet water, we shall have no trouble. We can cut straight across the stream and the distance to shore won't be great. I can do it all right." And do it he did, just how neither of the lads could have told. Nevertheless he did contrive to bring the boat and Laurie with it to a place of safety. Shoulder-deep in the water stood the frenzied Mr. Hazen who had plunged in to meet them and drag them to land. They had come so far down the river that when the canoe was finally beached they found themselves opposite the sweeping lawns of Pine Lea. Ted and the tutor were chilled and exhausted and Laurie was weak from fright and excitement. It did not take long, you may be sure, to summon help and bundle the three into a motor car which carried them to Pine Lea. Once there the invalid was put to bed and Mr. Hazen and Ted equipped with dry garments. "I shall get the deuce from the Fernalds for this!" commented the young tutor gloomily to Ted. "If it had not been for you, that boy would certainly have been drowned. Ugh! It makes me shudder to think of it! Had anything happened to him, I believe his father and grandfather would have lynched me." "Oh, Laurie is going to take all the blame," replied Ted, making an attempt to comfort the dejected young man. "He told me so himself." "That's all very well," rejoined Mr. Hazen, "but it won't help much. I shouldn't have left him. I had no right to do it, no matter what he said. I suppose the boat wasn't securely tied. It couldn't have been. Then the breeze came up. Goodness knows how the thing actually happened. I can't understand it now. But the point is, it did. Jove! I'm weak as a rag! I guess there can't be much left of you, Ted." "Oh, I'm all right now," protested Ted. "What got me was the fright of it. I didn't mind the swimming, for I've often crossed the river and back during my morning plunge. My work keeps me in pretty good training. But to-day I got panicky and my breath gave out. I was so afraid I wouldn't overtake the boat before----" "I know!" interrupted the tutor with a shiver. "Well, it is all over now, thank God! You were a genuine hero and I shall tell the Fernalds so." "Stuff! Don't tell them at all. What's the use of harrowing their feelings all up now that the thing is past and done with?" "But Laurie--he is all done up and they will be at a loss to account for it," objected Mr. Hazen. "Besides, the servants saw us come ashore and have probably already spread the story all over the place. And anyhow, I believe in being perfectly aboveboard. You do yourself, you know that. So I shall tell them the whole thing precisely as it happened. Afterward they'll probably fire me." "No, they won't! Cheer up!" "I deserve to be fired, too," went on the young tutor without heeding the interruption. "I ought not to have left Laurie an instant." "Perhaps not. But you won't do it again." "You bet I won't!" cried Mr. Hazen boyishly. It subsequently proved that Mr. Hazen knew far more of his employers than did Ted, for after the story was told only the pleas of the young rescuer availed to soften the sentence imposed. "He's almighty sorry, Mr. Fernald," asserted Ted Turner. "Don't tip him out. Give him a second try. He won't ever do it again." "W--e--ll, for your sake I will," Mr. Clarence said, yielding reluctantly to the pleading of the lad who sat opposite. "It would be hard for me to deny you anything after what you've done. You've saved our boy's life. We never shall forget it, never. But Hazen can thank you for his job--not me." And so, as a result of Ted's intercession, Mr. Hazen stayed on. In fact, as Mr. Clarence said, they could deny the lad nothing. It seemed as if the Fernalds never could do enough for him. Grandfather Fernald gave him a new watch with an illuminated face; and quite unknown to any one, Laurie's father opened a bank account to his credit, depositing a substantial sum as a "starter." But the best of the whole thing was that Laurie turned to Ted with a deeper and more earnest affection and the foundation was laid for a strong and enduring friendship. CHAPTER VIII DIPLOMACY AND ITS RESULTS Laurie, Ted, and Mr. Hazen were in the shack on a Saturday afternoon not long after the adventure on the river. A hard shower had driven them ashore and forced them to scramble into the shelter of the camp at the water's edge. How the rain pelted down on the low roof! It seemed as if an army were bombarding the little hut! Within doors, however, all was tight, warm, and cosy and on the hearth before a roaring fire the damp coats were drying. In the meantime the two boys and the young tutor had dragged out some coils of wire and a pair of amateur telephone transmitters which Ted had concocted while in school and for amusement were trying to run from one end of the room to the other a miniature telephone. Thus far their attempts had not been successful and Ted was becoming impatient. "We got quite a fair result at the laboratory after the things were adjusted," commented he. "I don't see why we can't work the same stunt here." "I'm afraid we haven't put time enough into it yet," replied Mr. Hazen. "Don't you remember how long Alexander Graham Bell, the inventor of the telephone, experimented before he got results?" Laurie, who was busy shortening a bit of wire, glanced up with interest. "I can't for the life of me understand how he knew what he wanted to do, can you?" he mused. "Think of starting out to make something perfectly new--a machine for which you had no pattern! I can imagine working out improvements on something already on the market. But to produce something nobody had ever seen before--that beats me! How did he ever get the idea in the first place?" The tutor smiled. "Mr. Bell did not set out to make a telephone, Laurie," he answered. "What he was aiming to do was to perfect a harmonic telegraph, a scheme to which he had been devoting a good deal of his time. He and his father had studied carefully the miracle of speech--how the sounds of the human voice were produced and carried to others--and as a result of this training Mr. Bell had become an expert teacher of the deaf. He was also professor of Vocal Physiology at Boston University where he had courses in lip reading, or a system of visible speech, which his father had evolved. This work kept him busy through the day so whatever experimenting he did with sounds and their vibrations had to be done at night." "So he stole time for electrical work, too, did he?" observed Ted. "I'm afraid that his interest in sound vibration caused him a sorry loss of sleep," said the tutor. "But certainly his later results were worth the amount of rest he sacrificed. One of the first agencies he employed to work upon was a piano. Have you ever tried singing a note into this instrument when the sustaining pedal is depressed? Do it some time and notice what happens. You will find that the string tuned to the pitch of your voice will start vibrating while all the others remain quiet. You can even go farther and try the experiment of uttering several different pitches, if you want to, and the corresponding strings will give back your notes, each one singling out its own particular vibration from the air. Now the results reached in these experiments with the piano strings meant a great deal more to Alexander Graham Bell than they would have meant to you or to me. In the first place, his training had given him a very acute ear; and in the next place, he was able to see in the facts presented a significance which an unskilled listener would not have detected. He found that this law of sympathetic vibration could be repeated electrically and, if desired, from a distance by means of electromagnets placed under a group of piano strings; and if afterward a circuit was made by connecting the magnets with an electric battery, you immediately had the same singing of the keys and a similar searching of each for its own pitch." "I'd like to try that trick some time," exclaimed Ted, leaning forward eagerly. "So should I!" echoed Laurie. "I think we could quite easily make the experiment if Laurie's mother would not object to our rigging up an attachment to her piano," Mr. Hazen responded. "Oh, Mater wouldn't mind," answered Laurie confidently. "She never minds anything I want to do." "I know she is a very long-suffering person," smiled the tutor. "Do you recall the white mice you had once, Laurie, and how they got loose and ran all over the house?" "And the chameleons! And the baby alligator!" chuckled Laurie. "Mother did get her back up over that alligator. She didn't like meeting him in the hall unexpectedly. But she wouldn't mind a thing that wasn't alive." "You call an electric wire dead then," said Ted with irony. "Well, no--not precisely," grinned Laurie. "Still I'm certain Mater would be less scared of it than she would of a mouse, even if the wire could kill her and the mouse couldn't." "Let's return to Mr. Bell and his piano strings," Ted remarked, after the laughter had subsided. Mr. Hazen's brow contracted thoughtfully and in his leisurely fashion he presently replied: "You can see, can't you, that if an interrupter caused the electric current to be made and broken at intervals, the number of times it interrupted per second would, for example, correspond to the rate of vibration in one of the strings? In other words, that would be the only string that would answer. Now if you sang into the piano, you would have the rhythmic impulse that set the piano strings vibrating coming directly through the air, while with the battery the impulse would come through the wire and the electromagnets instead. In each case, however, the principle involved would be the same." "I can see that," said Ted quickly. "Can't you, Laurie?" His chum nodded. "Now," continued Mr. Hazen, "just as it was possible to start two or more different notes of the piano echoing varying pitches, so it is possible to have several sets of these _make-and-break_ or intermittent currents start their corresponding strings to answering. In this way one could send several messages at once, each message being toned to a different pitch. All that would be necessary would be to have differently keyed interrupters. This was the principle of the harmonic telegraph at which Mr. Bell was toiling outside the hours of his regular work and through which he hoped to make himself rich and famous. His intention was to break up the various sounds into the dots and dashes of the Morse code and make one wire do what it had previously taken several wires to perform." "It seems simple enough," speculated Laurie. "It was not so simple to carry out," declared Mr. Hazen. "Of course, as I told you, Mr. Bell could not give his entire time to it. He had his teaching both at Boston University and elsewhere to do. Nor was he wholly free at the Saunders's, with whom he boarded at Salem, for he was helping the Saunders's nephew, who was deaf, to study." "And in return poor Mrs. Saunders had to offer up her piano for experiments, I suppose," Ted observed. "Well, perhaps at first--but not for long," was Mr. Hazen's reply. "Mr. Bell soon abandoned piano strings and in their place resorted to flat strips of springy steel, keying them to different pitches by varying their length. One end of these strips he fastened to a pole of an electromagnet and the other he extended over the other pole and left free." "And the current interrupters?" queried Ted. "Those current interrupters are the things which have since become known as transmitters," explained Mr. Hazen. "Those Mr. Bell made all alike except that in each one of them were springs kept in constant vibration by a magnet or point of metal placed above each spring so that the spring would touch it at every vibration, thus making and breaking the electric current the same number of times per second that corresponded to the pitch of the piece of steel. By tuning the springs of the receivers to the same pitch with the transmitters and running a wire between them equipped with signalling keys and a battery, Bell reasoned he could send as many messages at one time as there were pitches." "Did he get it to work?" Laurie asked. "Mr. Bell didn't, no," replied the tutor. "What sounded logical enough on paper was not so easy to put into practise. The idea has been carried out successfully, however, since then. But Mr. Bell unfortunately had no end of troubles with his scheme, and we all may thank these difficulties for the telephone, for had his harmonic telegraph gone smoothly we might not and probably would not have had Bell's other and far more important invention." "The discovery of the telephone was a 'happen,' then," Ted ventured. "More or less of a happen," was the reply. "Of course, the intelligent recognition of the law behind it was not a happen; nor was the patient and persistent toil that went into the perfecting of the instrument a matter of chance. Alexander Graham Bell had the genius to recognize the value and significance of the truth on which he stumbled and turn it to practical purposes. Many another might perhaps have heard the self-same sounds that came to him over that reach of wire and, detecting nothing unusual in the whining vibrations, have passed them by. But to Mr. Bell they were magic music, the sesame to a new country. Strangely enough, too, it was the good luck of a boy not much older than Ted to share with the discoverer the wonderful secret." "How?" demanded both Laurie and Ted in a breath. "I can't tell you that story to-day," Mr. Hazen expostulated. "It would take much too long. We must give over talking and put our minds on this telephone of our own which does not seem to be making any great progress. I begin to be afraid we haven't the proper outfit." As he spoke, a shadow crossed the window and in another instant Mr. Clarence Fernald poked his head in at the door. "What are you three conspirators up to?" inquired he. "You look as if you were making bombs or some other deadly thing." "We are making a telephone, Dad, and it won't work," was Laurie's answer. Mr. Fernald smiled with amusement. "You seem to have plenty of wire," he said. "In fact, if I were permitted to offer a criticism, I should say you had more wire than anything else. How lengthy a circuit do you expect to cover?" "Oh, we're not ambitious," Laurie replied. "If we can cross the room we shall be satisfied, although now that you mention it, perhaps it wouldn't be such a bad thing if it could run from my room at home over here." He eyed his father furtively. "Then when I happened to have to stay in bed I could talk to Ted and he could cheer me up." "So he could!" echoed Mr. Fernald in noncommittal fashion. "It would be rather nice, too, for Mr. Wharton," went on the diplomat with his sidelong glance still fixed on his father. "He must sometimes wish he could reach Ted without bothering to send a man way over here. And then there are the Turners! Of course a telephone to the shack would give them no end of pleasure. They must miss Ted and often want to speak with him." He waited but there was no response from Mr. Fernald. "Ted might be sick, too; or have an accident and wish to get help and----" At last the speaker was rewarded by having the elder man turn quickly upon him. "In other words, you young scoundrel, you want me to install a telephone in this shack for the joy and delight of you two electricians who can't seem to do it for yourselves," said Mr. Fernald gruffly. "Now however do you suppose he guessed it?" exclaimed Laurie delightedly, as he turned with mock gravity to Ted. "Isn't he the mind reader?" It was evident that Laurie Fernald thoroughly understood his father and that the two were on terms of the greatest affection. "Did I say I wanted a telephone?" he went on meekly. "You said everything else," was the grim retort. "Did I? Well, well!" commented the boy mischievously. "I needn't have taken so much trouble after all, need I? But every one isn't such a Sherlock Holmes as you are, Dad." Mr. Fernald's scowl vanished and he laughed. "What a young wheedler you are!" observed he, playfully rumpling up his son's fair hair. "You could coax every cent I have away from me if I did not lock my money up in the bank. I really think, though, that a telephone here in the hut would be an excellent idea. But what I don't see is why you don't do the job yourselves." "Oh, we could do the work all right if there wasn't danger of our infringing the patent of the telephone company," was Laurie's impish reply. "If we should get into a lawsuit there would be no end of trouble, you know. I guess we'd much better have the thing installed in the regular way." "I guess so too!" came from his father. "You'll really have it put in, Dad?" cried Laurie. "Sure!" "That will be bully, corking!" Laurie declared. "You're mighty good, Dad." "Pooh! Nonsense!" his father protested, as he shot a quick glance of tenderness toward the boy. "A telephone over here will be a useful thing for us all. I may want to call Ted up myself sometimes. We never can tell when an emergency may arise." Within the following week the telephone was in place and although Ted had not minded his seclusion, or thought he had not, he suddenly found that the instrument gave him a very comfortable sense of nearness to his family and to the household at Pine Lea. He and Laurie chattered like magpies over the wire and were far worse, Mrs. Fernald asserted, than any two gossipy boarding-school girls. Moreover, Ted was now able to speak each day with his father at the Fernald shipping rooms and by this means keep in closer touch with his family. As for Mr. Wharton, he marvelled that a telephone to the shack had not been put in at the outset. "It is not a luxury," he insisted. "It's a necessity! An indispensable part of the farm equipment!" Certainly in the days to come it proved its worth! CHAPTER IX THE STORY OF THE FIRST TELEPHONE "I am going down to Freeman's Falls this afternoon to get some rubber tape," Ted remarked to Laurie, as the two boys and the tutor were eating a picnic lunch in Ted's cabin one Saturday. "Oh, make somebody else do your errand and stay here," Laurie begged. "Anybody can buy that stuff. Some of the men must be going to the Falls. Ask Wharton to make them do your shopping." "Perhaps Ted had other things to attend to," ventured Mr. Hazen. "No, I hadn't," was the prompt reply. "In that case I am sure any of the men would be glad to get whatever you please," the tutor declared. "Save your energy, old man," put in Laurie. "Electrical supplies are easy enough to buy when you know what you want." "They are now," Mr. Hazen remarked, with a quiet smile, "but they have not always been. In fact, it was not so very long ago that it was almost impossible to purchase either books on electricity or electrical stuff of any sort. People's knowledge of such matters was so scanty that little was written about them; and as for shops of this type--why, they were practically unknown." "Where did persons get what they wanted?" asked Ted with surprise. "Nobody wanted electrical materials," laughed Mr. Hazen. "There was no call for them. Even had the shops supplied them, nobody would have known what to do with them." "But there must have been some who would," the boy persisted. "Where, for example, did Mr. Bell get his things?" "Practically all Mr. Bell's work was done at a little shop on Court Street, Boston," answered Mr. Hazen. "This shop, however, was nothing like the electrical supply shops we have now. Had Alexander Graham Bell entered its doors and asked, for instance, for a telephone transmitter, he would have found no such thing in stock. On the contrary, the shop consisted of a number of benches where men or boys experimented or made crude electrical contrivances that had previously been ordered by customers. The shop was owned by Charles Williams, a clever mechanical man, who was deeply interested in electrical problems of all sorts. In a tiny showcase in the front part of the store were displayed what few textbooks on electricity he had been able to gather together and these he allowed the men in his employ to read at lunch time and to use freely in connection with their work. He was a person greatly beloved by those associated with him and he had the rare wisdom to leave every man he employed unhampered, thereby making individual initiative the law of his business." The tutor paused, then noticing that both the boys were listening intently, he continued: "If a man had an idea that had been carefully thought out, he was given free rein to execute it. Tom Watson, one of the boys at the shop, constructed a miniature electric engine, and although the feat took both time and material, there was no quarrel because of that. The place was literally a workshop, and so long as there were no drones in it and the men toiled intelligently, Mr. Williams had no fault to find. You can imagine what valuable training such a practical environment furnished. Nobody nagged at the men, nobody drove them on. Each of the thirty or forty employees pegged away at his particular task, either doing work for a specific customer or trying to perfect some notion of his own. If you were a person of ideas, it was an ideal conservatory in which to foster them." "Gee! I'd have liked the chance to work in a place like that!" Ted sighed. "It would not have been a bad starter, I assure you," agreed Mr. Hazen. "At that time there were, as I told you, few such shops in the country; and this one, simple and crude as it was, was one of the largest. There was another in Chicago which was bigger and perhaps more perfectly organized; but Williams's shop was about as good as any and certainly gave its men an excellent all-round education in electrical matters. Many of them went out later and became leaders in the rapidly growing world of science and these few historic little shops thus became the ancestors of our vast electrical plants." "It seems funny to think it all started from such small beginnings, doesn't it," mused Laurie thoughtfully. "It certainly is interesting," Mr. Hazen replied. "And if it interests us in this far-away time, think what it must have meant to the pioneers to witness the marvels half a century brought forth and look back over the trail they had blazed. For it was a golden era of discovery, that period when the new-born power of electricity made its appearance; and because Williams's shop was known to be a nursery for ideas, into it flocked every variety of dreamer. There were those who dreamed epoch-making dreams and eventually made them come true; and there were those who merely saw visions too impractical ever to become realities. To work amid this mecca of minds must have been not only an education in science but in human nature as well. Every sort of crank who had gathered a wild notion out of the blue meandered into Williams's shop in the hope that somebody could be found there who would provide either the money or the labor to further his particular scheme. "Now in this shop," went on Mr. Hazen, "there was, as I told you, a young neophyte by the name of Thomas Watson. Tom had not found his niche in life. He had tried being a clerk, a bookkeeper, and a carpenter and none of these several occupations had seemed to fit him. Then one fortunate day he happened in at Williams's shop and immediately he knew this was the place where he belonged. He was a boy of mechanical tastes who had a real genius for tools and machinery. He was given a chance to turn castings by hand at five dollars a week and he took the job eagerly." "Think how a boy would howl at working for that now," Laurie exclaimed. "No doubt there were boys who would have howled then," answered Mr. Hazen, "although in those days young fellows expected to work hard and receive little pay until they had learned their trade. Perhaps the youthful Mr. Watson had the common sense to cherish this creed; at any rate, there was not a lazy bone in his body, and as there were no such things to be had as automatic screw machines, he went vigorously to work making the castings by hand, trying as he did so not to blind his eyes with the flying splinters of metal." "Then what happened?" demanded Laurie. "Well, Watson stuck at his job and in the meantime gleaned right and left such scraps of practical knowledge as a boy would pick up in such a place. By the end of his second year he had had his finger in many pies and had worked on about every sort of electrical contrivance then known: call bells, annunciators, galvanometers; telegraph keys, sounders, relays, registers, and printing telegraph instruments. Think what a rich experience his two years of apprenticeship had given him!" "You bet!" ejaculated Ted appreciatively. "Now as Tom Watson was not only clever but was willing to take infinite pains with whatever he set his hand to, never stinting nor measuring his time or strength, he became a great favorite with those who came to the shop to have different kinds of experimental apparatus made. Many of the ideas brought to him to be worked out came from visionaries who had succeeded in capturing the financial backing of an unwary believer and convinced themselves and him that here was an idea that was to stir the universe. But too many of these schemes, alas, proved worthless and as their common fate was the rubbish heap, it is strange that the indefatigable Thomas Watson did not have his faith in pioneer work entirely destroyed. But youth is buoyed up by perpetual hope; and paradoxical as it may seem, his enthusiasm never lagged. Each time he felt, with the inventor, that they might be standing on the brink of gigantic unfoldings and he toiled with energy to bring something practical out of the chaos. And when at length it became evident beyond all question that the idea was never to unfold into anything practical, he would, with the same zealous spirit, attack another seer's problem." "Didn't he ever meet any successful inventors?" questioned Ted. "Yes, indeed," the tutor answered. "Scattered among the cranks and castle builders were several brilliant, solid-headed men. There was Moses G. Farmer, for example, one of the foremost electricians of that time, who had many an excellent and workable idea and who taught young Watson no end of valuable lessons. Then one day into the workshop came Alexander Graham Bell. In his hand he carried a mechanical contrivance Watson had previously made for him and on espying Tom in the distance he made a direct line for the workman's bench. After explaining that the device did not do the thing he was desirous it should, he told Watson that it was the receiver and transmitter of his Harmonic Telegraph." "And that was the beginning of Mr. Watson's work with Mr. Bell?" asked Ted breathlessly. "Yes, that was the real beginning." "Think of working with a man like that!" the boy cried with sparkling eyes. "It must have been tremendously interesting." "It was interesting," responded Mr. Hazen, "but nevertheless much of the time it must have been inexpressibly tedious work. A young man less patient and persistent than Watson would probably have tired of the task. Just why he did not lose his courage through the six years of struggle that followed I do not understand. For how was he to know but that this idea would eventually prove as hopeless and unprofitable as had so many others to which he had devoted his energy? Beyond Mr. Bell's own magnetic personality there was only slender foundation for his faith for in spite of the efforts of both men the harmonic telegraph failed to take form. Instead, like a tantalizing sprite, it danced before them, always beckoning, never materializing. In theory it was perfectly consistent but in practise it could not be coaxed into behaving as it logically should. Had it but been possible for those working on it to realize that beyond their temporary failure lay a success glorious past all belief, think what the knowledge would have meant. But to always be following the gleam and never overtaking it, ah, that might well have discouraged prophets of stouter heart!" "Were these transmitters and receivers made from electromagnets and strips of flat steel, as you told us the other day?" asked Ted. "Yes, their essential parts comprised just those elements--an electromagnet and a scrap of flattened clock spring which, as I have explained, was clamped by one end to the pole of the magnet and left free at the other to vibrate over the opposite pole. In addition the transmitter had make-and-break points such as an ordinary telephone bell has, and when these came in contact with the current, the springs inside continually gave out a sort of wail keyed to correspond with the pitch of the spring. As Mr. Bell had six of these instruments tuned to as many different pitches--and six receivers to answer them--you may picture to yourself the hideousness of the sounds amid which the experimenters labored." "I suppose when each transmitter sent out its particular whine its own similarly tuned receiver spring would wriggle in response," Laurie said. "Exactly so." "There must have been lovely music when all six of them began to sing!" laughed Ted. "Mr. Watson wrote once that it was as if all the miseries of the world were concentrated in that workroom, and I can imagine it being true," answered the tutor. "Well, young Watson certainly did all he could to make the harmonic telegraph a reality. He made the receivers and transmitters exactly as Mr. Bell requested; but on testing them out, great was the surprise of the inventor to find that his idea, so feasible in theory, refused to work. Nevertheless, his faith was not shaken. He insisted on trying to discover the flaw in his logic and correct it, and as Watson had now completed some work that he had been doing for Moses Farmer, the two began a series of experiments that lasted all winter." "Jove!" ejaculated Laurie. "Marvels of science are not born in a moment," answered Mr. Hazen. "Yet I do not wonder that you gasp, for think of what it must have meant to toil for weeks and months at those wailing instruments! It is a miracle the men did not go mad. They were not always able to work together for Mr. Bell had his living to earn and therefore was compelled to devote a good measure of his time to his college classes and his deaf pupils. In consequence, he did a portion of his experimental work at Salem while Watson carried on his at the shop, fitting it in with other odd jobs that came his way. Frequently Mr. Bell remained in Boston in the evening and the two worked at the Williams's shop until late into the night." "Wasn't it lucky there were no labor unions in those days?" put in Ted mischievously. "Indeed it was!" responded Mr. Hazen. "The shop would then have been barred and bolted at five o'clock, I suppose, and Alexander Graham Bell might have had a million bright ideas for all the good they would have done him. But at that golden period of our history, if an ambitious fellow like Watson wished to put in extra hours of work, the more slothful ones had no authority to stand over him with a club and say he shouldn't. Therefore the young apprentice toiled on with Mr. Bell, unmolested; and Charles Williams, the proprietor of the shop, was perfectly willing he should. One evening, when the two were alone, Mr. Bell remarked, 'If I could make a current of electricity vary in intensity precisely as the air varies in density during the production of sound, I should be able to transmit speech telegraphically.' This was his first allusion to the telephone but that the idea of such an instrument had been for some time in his mind was evident by the fact that he sketched in for Watson the kind of apparatus he thought necessary for such a device and they speculated concerning its construction. The project never went any farther, however, because Mr. Thomas Saunders and Mr. Gardiner Hubbard, who were financing Mr. Bell's experiments, felt the chances of this contrivance working satisfactorily were too uncertain. Already much time and money had been spent on the harmonic telegraph and they argued this scheme should be completed before a new venture was tried." "I suppose that point of view was quite justifiable," mused Ted. "But wasn't it a pity?" "Yes, it was," agreed Mr. Hazen. "Yet here again we realize how man moves inch by inch, never knowing what is just around the turn of the road. He can only go it blindly and do the best he knows at the time. Naturally neither Mr. Hubbard nor Mr. Saunders wanted to swamp any more money until they had received results for what they had spent already; and those results, alas, were not forthcoming. Over and over again poor Watson blamed himself lest some imperceptible defect in his part of the work was responsible for Mr. Bell's lack of success. The spring of 1875 came and still no light glimmered on the horizon. The harmonic telegraph seemed as far away from completion as ever. Patiently the men plodded on. Then on a June day, a day that began even less auspiciously than had other days, the heavens suddenly opened and Alexander Graham Bell had his vision!" "What was it?" "Tell us about it!" cried both boys in a breath. "It was a warm, close afternoon in the loft over the Williams's shop and the transmitters and receivers were whining there more dolefully than usual. Several of them, sensitive to the weather, were out of tune, and as Mr. Bell had trained his ear to sounds until it was abnormally acute, he was tuning the springs of the receivers to the pitch of the transmitters, a service he always preferred to perform himself. To do this he placed the receiver against his ear and called to Watson, who was in the adjoining room, to start the current through the electromagnet of the corresponding transmitter. When this was done, Mr. Bell was able to turn a screw and adjust the instrument to the pitch desired. Watson admits in a book he has himself written that he was out of spirits that day and feeling irritable and impatient. The whiners had got on his nerves, I fancy. One of the springs that he was trying to start appeared to stick and in order to force it to vibrate he gave it a quick snap with his finger. Still it would not go and he snapped it sharply several times. Immediately there was a cry from Mr. Bell who rushed into the hall, exclaiming, 'What did you do then? Don't change anything. Let me see.' "Watson was alarmed. Had he knocked out the entire circuit or what had he done in his fit of temper? Well, there was no escape from confession now; no pretending he had not vented his nervousness on the mechanism before him. With honesty he told the truth and even illustrated his hasty action. The thing was simple enough. In some way the make-and-break points of the transmitter spring had become welded together so that even when Watson snapped the instrument the circuit had remained unbroken, while by means of the piece of magnetized steel vibrating over the pole of the magnet an electric current was generated, the type of current that did exactly what Mr. Bell had dreamed of a current doing--a current of electricity that varied in intensity precisely as the air within the radius of that particular spring was varying in density. And not only did that undulatory current pass through the wire to the receiver Mr. Bell was holding, but as good luck would have it the mechanism was such that it transformed that current back into a faint but unmistakable echo of the sound issuing from the vibrating spring that generated it. But a fact more fortunate than all this was that the one man to whom the incident carried significance had the instrument at his ear at that particular moment. That was pure chance--a Heaven-sent, miraculous coincidence! But that Mr. Bell recognized the value and importance of that whispered echo that reached him over the wire and knew, when he heard it, that it was the embodiment of the idea that had been haunting him--that was not chance; it was genius!" The room had been tensely still and now both boys drew a sigh of relief. "How strange!" murmured Ted in an awed tone. "Yes, it was like magic, was it not?" replied the tutor. "For the speaking telephone was born at that moment. Whatever practical work was necessary to make the invention perfect (and there were many, many details to be solved) was done afterward. But on June 2, 1875, the telephone as Bell had dreamed it came into the world. That single demonstration on that hot morning in Williams's shop proved myriad facts to the inventor. One was that if a mechanism could transmit the many complex vibrations of one sound it could do the same for any sound, even human speech. He saw now that the intricate paraphernalia he had supposed necessary to achieve his long-imagined result was not to be needed, for did not the simple contrivance in his hand do the trick? The two men in the stuffy little loft could scarcely contain their delight. For hours they went on repeating the experiment in order to make sure they were really awake. They verified their discovery beyond all shadow of doubt. One spring and then another was tried and always the same great law acted with invariable precision. Heat, fatigue, even the dingy garret itself was forgotten in the flight of those busy, exultant hours. Before they separated that night, Alexander Graham Bell had given to Thomas Watson directions for making the first electric speaking telephone in the world!" CHAPTER X WHAT CAME AFTERWARD "Was that first telephone like ours?" inquired Ted later as, their lunch finished, they sat idly looking out at the river. "Not wholly. Time has improved the first crude instrument," Mr. Hazen replied. "The initial principle of the telephone, however, has never varied from Mr. Bell's primary idea. Before young Watson tumbled into bed on that epoch-making night, he had finished the instrument Bell had asked him to have ready, every part of it being made by the eager assistant who probably only faintly realized the mammoth importance of his task. Yet whether he realized it or not, he had caught a sufficient degree of the inventor's excitement to urge him forward. Over one of the receivers, as Mr. Bell directed, he mounted a small drumhead of goldbeater's skin, joined the center of it to the free end of the receiver spring, and arranged a mouthpiece to talk into. The plan was to force the steel spring to answer the vibrations of the voice and at the same time generate a current of electricity that should vary in intensity just as the air varies in density during the utterance of speech sounds. Not only did Watson make this instrument as specified, but in his interest he went even farther, and as the rooms in the loft seemed too near together, the tireless young man ran a special wire from the attic down the two flights of stairs to the ground floor of the shop and ended it near his workbench at the rear of the building, thus constructing the first telephone line in history. "Then the next day Mr. Bell came to test out his invention and, as you can imagine, there was great excitement." "I hope it worked," put in Laurie. "It worked all right although at this early stage of the game it was hardly to be expected that the instrument produced was perfect. Nevertheless, the demonstration proved that the principle behind it was sound and that was all Mr. Bell really wanted to make sure of. Watson, as it chanced, got far more out of this initial performance than did Mr. Bell himself for because of the inventor's practical work in phonics the vibrations of his voice carried more successfully than did those of the assistant. Yet the youthful Watson was not without his compensations. Nature had blessed him with unusually acute hearing and as a result he could catch Bell's tones perfectly as they came over the wire and could almost distinguish his words; but shout as he would, poor Mr. Bell could not hear _him_. This dilemma nevertheless discouraged neither of them for Watson had plenty of energy and was quite willing to leap up the two flights of stairs and repeat what he had heard; and this report greatly reassured Mr. Bell, who outlined a list of other improvements for another telephone that should be ready on the following day." "I suppose they kept remodelling the telephones all the time after that, didn't they?" inquired Ted. "You may be sure they did," was Mr. Hazen's response. "The harmonic telegraph was entirely sidetracked and the interest of both men turned into this newer channel. Mr. Bell, in the meantime, was giving less and less energy to his teaching and more and more to his inventing. Before many days the two could talk back and forth and hear one another's voices without difficulty, although ten full months of hard work was necessary before they were able to understand what was said. It was not until after this long stretch of patient toil that Watson unmistakably heard Mr. Bell say one day, '_Mr. Watson, please come here, I want you._' The message was a very ordinary, untheatrical one for a moment so significant but neither of the enthusiasts heeded that. The thrilling fact was that the words had come clear-cut over the wire." "Gee!" broke in Laurie. "It certainly must have been a dramatic moment," Mr. Hazen agreed. "Mr. Bell, now convinced beyond all doubt of the value of his idea, hired two rooms at a cheap boarding-house situated at Number 5 Exeter Place, Boston. In one of these he slept and in the other he equipped a laboratory. Watson connected these rooms by a wire and afterward all Mr. Bell's experimenting was done here instead of at the Williams's shop. It was at the Exeter Place rooms that this first wonderful message came to Watson's ears. From this period on the telephone took rapid strides forward. By the summer of 1876, it had been improved until a simple sentence was understandable if carefully repeated three or four times." "Repeated three or four times!" gasped Laurie in dismay. The tutor smiled at the boy's incredulousness. "You forget we are not dealing with a finished product," said he gently. "I am a little afraid you would have been less patient with the imperfections of an infant invention than were Bell and Watson." "I know I should," was the honest retort. "The telephone was a very delicate instrument to perfect," explained Mr. Hazen. "Always remember that. An inventor must not only be a man who has unshaken faith in his idea but he must also have the courage to cling stubbornly to his belief through every sort of mechanical vicissitude. This Mr. Bell did. June of 1876 was the year of the great Centennial at Philadelphia, the year that marked the first century of our country's progress. As the exhibition was to be one symbolic of our national development in every line, Mr. Bell decided to show his telephone there; to this end he set Watson, who was still at the Williams's shop, to making exhibition telephones of the two varieties they had thus far worked out." "I'll bet Watson was almighty proud of his job," Ted interrupted. "I fancy he was and certainly he had a right to be," answered Mr. Hazen. "I have always been glad, too, that it fell to his lot to have this honor; for he had worked long and faithfully, and if there were glory to be had, he should share it. To his unflagging zeal and intelligence Mr. Bell owed a great deal. Few men could so whole-heartedly have effaced their own personality and thrown themselves with such zest into the success of another as did Thomas Watson." The tutor paused. "Up to this time," he presently went on, "the telephones used by Bell and Watson in their experiments had been very crude affairs; but those designed for the Centennial were glorified objects. Watson says that you could see your face in them. The Williams's shop outdid itself and more splendid instruments never went forth from its doors. You can therefore imagine Watson's chagrin when, after highly commending Mr. Bell's invention, Sir William Thompson added, '_This, perhaps, greatest marvel hitherto achieved by electric telegraph has been obtained by appliances of quite a homespun and rudimentary character._'" Both Ted and Laurie joined in the laughter of the tutor. "And now the telephone was actually launched?" Ted asked. "Well, it was not really in clear waters," Mr. Hazen replied, with a dubious shrug of his shoulders, "but at least there was no further question as to which of his schemes Mr. Bell should perfect. Both Mr. Hubbard and Mr. Saunders, who were assisting him financially, agreed that for the present it must be the telephone; and recognizing the value of Watson's services, they offered him an interest in Mr. Bell's patents if he would give up his work at Williams's shop and put in all his time on this device. Nevertheless they did not entirely abandon the harmonic telegraph for Bell's success with the other invention had only served to strengthen their confidence in his ability and genius. It was also decided that Mr. Bell should move from Salem to Boston, take an additional room at the Exeter Place house (which would give him the entire floor where his laboratory was), and unhampered by further teaching plunge into the inventive career for which heaven had so richly endowed him and which he loved with all his heart. You can picture to yourselves the joy these decisions gave him and the eagerness with which he and Watson took up their labors together. "They made telephones of every imaginable size in their attempts to find out whether there was anything that would work more satisfactorily than the type they now had. But in spite of their many experiments they came back to the kind of instrument with which they had started, discovering nothing that was superior to their original plan. Except that they compelled the transmitter to do double duty and act also as a receiver, the telephone that emerged from these many tests was practically similar in principle to the one of to-day." "Had they made any long-distance trials up to this time?" questioned Laurie. "No," Mr. Hazen admitted. "They had lacked opportunity to make such tests since no great span of wires was accessible to them. But on October 9, 1876, the Walworth Manufacturing Company gave them permission to try out their device on the Company's private telegraph line that ran from Boston to Cambridge. The distance to be sure was only two miles but it might as well have been two thousand so far as the excitement of the two workers went. Their baby had never been out of doors. Now at last it was to take the air! Fancy how thrilling the prospect was! As the wire over which they were to make the experiment was in use during the day, they were forced to wait until the plant was closed for the night. Then Watson, with his tools and his telephone under his arm, went to the Cambridge office where he impatiently listened for Mr. Bell's signal to come over the Morse sounder. When he had heard this and thereby made certain that Bell was at the other end of the line, he cut out the sounder, connected the telephone he had brought with him, and put his ear to the transmitter." The hut was so still one could almost hear the breathing of the lads, who were listening intently. "Go on!" Laurie said quickly. "Tell us what happened." "_Nothing happened!_" answered the tutor. "Watson listened but there was not a sound." "Great Scott!" "The poor assistant was aghast," went on Mr. Hazen. "He was at a complete loss to understand what was the matter. Could it be that the contrivance which worked so promisingly in the Boston rooms would not work under these other conditions? Perhaps an electric current was too delicate a thing to carry sound very far. Or was it that the force of the vibration filtered off at each insulator along the line until it became too feeble to be heard? All these possibilities flashed into Watson's mind while at his post two miles away from Mr. Bell he struggled to readjust the instrument. Then suddenly an inspiration came to his alert brain. Might there not be another Morse sounder somewhere about? If there were, that would account for the whole difficulty. Springing up, he began to search the room and after following the wires, sure enough, he traced them to a relay with a high resistance coil in the circuit. Feverishly he cut this out and rushed back to his telephone. Plainly over the wire came Bell's voice, '_Ahoy! Ahoy!_' For a few seconds both of them were too delighted to say much of anything else. Then they sobered down and began this first long-distance conversation. Now one of the objections Mr. Bell had constantly been forced to meet from the skeptical public was that while the telegraph delivered messages that were of unchallenged accuracy telephone conversations were liable to errors of misunderstanding. One could not therefore rely so completely on the trustworthiness of the latter as on that of the former. To refute this charge Mr. Bell had insisted that both he and Watson carefully write out whatever they heard that the two records might afterward be compared and verified. '_That is_,' Mr. Bell had added with the flicker of a smile, '_if we succeed in talking at all_!' Well, they did succeed, as you have heard. At first they held only a stilted dialogue and conscientiously jotted it down; but afterward their exuberance got the better of them and in sheer joy they chattered away like magpies until long past midnight. Then, loath to destroy the connection, Watson detached his telephone, replaced the Company's wires, and set out for Boston. In the meantime Mr. Bell, who had previously made an arrangement with the _Boston Advertiser_ to publish on the following morning an account of the experiment, together with the recorded conversations, had gone to the newspaper office to carry his material to the press. Hence he was not at the Exeter Place rooms when the jubilant Watson arrived. But the early morning hour did not daunt the young electrician; and when, after some delay, Mr. Bell came in, the two men rushed toward one another and regardless of everything else executed what Mr. Watson has since characterized as a _war dance_. Certainly they were quite justified in their rejoicings and perhaps if their landlady had understood the cause of their exultations she might have joined in the dance herself. Unluckily she had only a scant sympathy with inventive genius and since the victory celebration not only aroused her, but also wakened most of her boarders from their slumbers, her ire was great and the next morning she informed the two men that if they could not be more quiet at night they would have to leave her house." An appreciative chuckle came from the listeners. "If she had known what she was sheltering, I suppose she would have been proud as a peacock and promptly told all her neighbors," grinned Ted. "Undoubtedly! But she did not know, poor soul!" returned Mr. Hazen. "After this Mr. Bell and Mr. Watson must have shot ahead by leaps and bounds," commented Laurie. "There is no denying that that two-mile test did give them both courage and assurance," responded the tutor. "They got chances to try out the invention on longer telegraph wires; and in spite of the fact that no such thing as hard-drawn copper wire was in existence they managed to get results even over rusty wires with their unsoldered joinings. Through such experiments an increasingly wider circle of outside persons heard of the telephone and the marvel began to attract greater attention. Mr. Bell's modest little laboratory became the mecca of scientists and visitors of every imaginable type. Moses G. Farmer, well known in the electrical world, came to view the wonder and confessed to Mr. Bell that more than once he had lingered on the threshold of the same mighty discovery but had never been able to step across it into success. It amused both Mr. Bell and Mr. Watson to see how embarrassed persons were when allowed to talk over the wire. Standing up and speaking into a box has long since become too much a matter of course with us to appear ridiculous; but those experiencing the novelty for the first time were so overwhelmed by self-consciousness that they could think of nothing to say. One day when Mr. Watson called from his end of the line, 'How do you do?' a dignified lawyer who was trying the instrument answered with a foolish giggle, 'Rig-a-jig-jig and away we go!' The psychological reaction was too much for many a well-poised individual and I do not wonder it was, do you?" "It must have been almost as good as a vaudeville show to watch the people," commented Ted. "Better! Lots better!" echoed Laurie. "In April, 1877, the first out-of-door telephone line running on its own private wires was installed in the shop of Charles Williams at Number 109 Court Street and carried from there out to his house at Somerville. Quite a little ceremony marked the event. Both Mr. Bell and Mr. Watson attended the christening and the papers chronicled the circumstance in bold headlines the following day. Immediately patrons who wanted telephones began to pop up right and left like so many mushrooms. But alas, where was the money to come from that should enable Mr. Bell and his associates to branch out and grasp the opportunities that now beckoned them? The inventor's own resources were at a low ebb; Watson, like many another young man, had more brains than fortune; and neither Mr. Hubbard nor Mr. Saunders felt they could provide the necessary capital. Already the Western Union had refused Mr. Hubbard's offer to sell all Mr. Bell's patents for one hundred thousand dollars, the Company feeling that the price asked was much too high. Two years later, however, they would willingly have paid twenty-five million dollars for the privilege they had so summarily scorned. What was to be done? Money must be secured for without it all further progress was at a standstill. Was success to be sacrificed now that the goal was well within sight? And must the telephone be shut away from the public and never take its place of service in the great world? Why, if a thing was not to be used it might almost as well never have been invented! The spirits of the telephone pioneers sank lower and lower. The only way to raise money seemed to be to sell the telephone instruments outright and this Mr. Bell, who desired simply to lease them, was unwilling to do. Then an avenue of escape from this dilemma presented itself to him." "What was it?" asked Laurie. "He would give lectures, accompanying them with practical demonstrations of the telephone. This would bring in money and banish for a time, at least, the possibility of having to sell instead of rent telephones. The plan succeeded admirably. The first lecture was given at Salem where, because of Mr. Bell's previous residence and many friends, a large audience packed the hall. Then Boston desired to know more of the invention and an appeal for a lecture signed by Longfellow, Oliver Wendell Holmes, and other distinguished citizens was forwarded to Mr. Bell. The Boston lectures were followed by others in New York, Providence, and the principal cities throughout New England." "It seems a shame Mr. Bell should have had to take his time to do that, doesn't it?" mused Ted. "How did they manage the lectures?" "The lectures had a checkered existence," smiled Mr. Hazen. "Many very amusing incidents centered about them. Were I to talk until doomsday I could not begin to tell you the multitudinous adventures Mr. Bell and Mr. Watson had during their platform career; for although Mr. Watson was never really before the footlights as Mr. Bell was, he was an indispensable part of the show,--the power behind the scenes, the man at the other end of the wire, who furnished the lecture hall with such stunts as would not only convince an audience but also entertain them. It was a dull, thankless position, perhaps, to be so far removed from the excitement and glamor, to be always playing or singing into a little wooden box and never catching a glimpse of the fun that was going on at the other end of the line; but since Mr. Watson was a rather shy person it is possible he was quite as well pleased. After all, it was Mr. Bell whom everybody wanted to see and of course Mr. Watson understood this. Therefore he was quite content to act his modest rôle and not only gather together at his end of the wire cornet soloists, electric organs, brass bands, or whatever startling novelties the occasion demanded, but talk or sing himself. The shyest of men can sometimes out-Herod Herod if not obliged to face their listeners in person. As Watson had spoken so much over the telephone, he was thoroughly accustomed to it and played the parts assigned him far better than more gifted but less practically trained soloists did. It always amused him intensely after he had bellowed _Pull for the Shore_, _Hold the Fort_ or _Yankee Doodle_ into the transmitter to hear the applause that followed his efforts. Probably singing before a large company was about the last thing Tom Watson expected his electrical career would lead him into. Had he been told that such a fate awaited him, he would doubtless have jeered at the prophecy. But here he was, singing away with all his lung power, before a great hall full of people and not minding it in the least; nay, I rather think he may have enjoyed it. Once, desiring to give a finer touch than usual to the entertainment, Mr. Bell hired a professional singer; but this soloist had never used a telephone and although he possessed the art of singing he was not able to get it across the wire. No one in the lecture hall could hear him. Mr. Bell promptly summoned Watson (who was doubtless congratulating himself on being off duty) to render _Hold the Fort_ in his customary lusty fashion. After this Mr. Watson became the star soloist and no more singers were engaged." A ripple of amusement passed over the faces of the lads listening. "Ironically enough, as Mr. Watson's work kept him always in the background furnishing the features of these entertainments, he never himself heard Mr. Bell lecture. He says, however, that the great inventor was a very polished, magnetic speaker who never failed to secure and hold the attention of his hearers. Of course, every venture has its trials and these lecture tours were no exception to the general rule. Once, for example, the Northern Lights were responsible for demoralizing the current and spoiling a telephone demonstration at Lawrence; and although both Watson and a cornetist strained their lungs to bursting, neither of them could be heard at the hall. Then the sparks began to play over the wires and the show had to be called off. Nevertheless such disasters occurred seldom, and for the most part the performances went smoothly, the people were delighted, and Mr. Bell increased not only his fame but his fortune." Mr. Hazen stopped a moment. "You must not for an instant suppose," he resumed presently, "that the telephone was a perfected product. Transmitters of sufficient delicacy to do away with shouting and screaming had not yet made their appearance and in consequence when one telephoned all the world knew it; it was not until the Blake transmitter came into use that a telephone conversation could be to any extent confidential. In its present state, the longer the range the more lung power was demanded; and probably had not this been the condition, people would have shouted anyway, simply from instinct. Even with our own delicately adjusted instruments we are prone to forget and commit this folly. But in the early days one was forced to uplift his voice at the telephone and if he had no voice to uplift woe betide his telephoning. And apropos of this matter, I recall reading that once, when Mr. Bell was to lecture in New York, he thought what a drawing card it would be if he could have his music and other features of entertainment come from Boston. Therefore he arranged to use the wires of the Atlantic and Pacific Telegraph Company and to this end he and Watson planned a dress rehearsal at midnight in order to try out the inspiration. Now it chanced that the same inflexible landlady ruled at Number 5 Exeter Place, and remembering his former experience, Mr. Watson felt something must be done to stifle the shouting he foresaw he would be compelled to do at that nocturnal hour. So he gathered together all the blankets and rolled them into a sort of cone and to the small end of this he tied his telephone. Then he crept into this stuffy, breathless shelter, the ancestor of our sound-proof telephone booth, and for nearly three hours shouted to Mr. Bell in New York--or tried to. But the experiment was not a success. He could be heard, it is true, but not distinctly enough to risk such an unsatisfactory demonstration before an uninitiated audience. Hence the scheme was abandoned and Mr. Watson scrambled his things together and betook himself to a point nearer the center of action." "It must all have been great fun, mustn't it?" said Laurie thoughtfully. "Great fun, no doubt, but very hard work," was the tutor's answer. "Many a long, discouraging hour was yet to follow before the telephone became a factor in the everyday world. Yet each step of the climb to success had its sunlight as well as its shadow, its humor as well as its pathos; and it was fortunate both men appreciated this fact for it floated them over many a rough sea. Man can spare almost any other attribute better than his sense of humor. Without this touchstone he is ill equipped to battle with life," concluded Mr. Hazen whimsically. CHAPTER XI THE REST OF THE STORY "I should think," commented Laurie one day, when Ted and Mr. Hazen were sitting in his room, "that Mr. Bell's landlady would have fussed no end to have his telephone ringing all the time." "My dear boy, you do not for an instant suppose that the telephones of that period had bells, do you?" replied Mr. Hazen with amusement. "No, indeed! There was no method for signaling. Unless two persons agreed to talk at a specified hour of the day or night and timed their conversation by the clock, or else had recourse to the Morse code, there was no satisfactory way they could call one another. This did not greatly matter when you recollect how few telephones there were in existence. Mr. Williams used to summon a listener by tapping on the metal diaphragm of the instrument with his pencil, a practice none too beneficial to the transmitter; nor was the resulting sound powerful enough to reach any one who was not close at hand. Furthermore, persons could not stand and hold their telephones and wait until they could arouse the party at the other end of the line for a telephone weighed almost ten pounds and----" "Ten pounds!" repeated Ted in consternation. Mr. Hazen nodded. "Yes," answered he, "the early telephones were heavy, cumbersome objects and not at all like the trim, compact instruments we have to-day. In fact, they were quite similar to the top of a sewing-machine box, only, perhaps, they were a trifle smaller. You can understand that one would not care to carry on a very long conversation if he must in the meantime stand and hold in his arms a ten-pound object about ten inches long, six inches wide, and six inches high." "I should say not!" Laurie returned. "It must have acted as a fine check, though, on people who just wanted to gabble." Both Ted and the tutor laughed. "Of course telephone owners could not go on that way," Ted said, after the merriment had subsided. "What did Mr. Bell do about it?" "The initial step for betterment was not taken by Mr. Bell but by Mr. Watson," Mr. Hazen responded. "He rigged a little hammer inside the box and afterwards put a button on the outside. This _thumper_ was the first calling device ever in use. Later on, however, the assistant felt he could improve on this method and he adapted the buzzer of the harmonic telegraph to the telephone; this proved to be a distinct advance over the more primitive _thumper_ but nevertheless he was not satisfied with it as a signaling apparatus. So he searched farther still, and with the aid of one of the shabby little books on electricity that he had purchased for a quarter from Williams's tiny showcase, he evolved the magneto-electric call bell such as we use to-day. This answered every purpose and nothing has ever been found that has supplanted it. It is something of a pity that Watson did not think to affix his name to this invention; but he was too deeply interested in what he was doing and probably too busy to consider its value. His one idea was to help Mr. Bell to improve the telephone in every way possible and measuring what he was going to get out of it was apparently very far from his thought. Of course, the first of these call bells were not perfect, any more than were the first telephones; by and by, however, their defects were remedied until they became entirely satisfactory." "So they now had telephones, transmitters, and call bells," reflected Ted. "I should say they were pretty well ready for business." "You forget the switchboard," was Mr. Hazen's retort. "A one-party line was a luxury and a thing practically beyond the reach of the public. At best there were very few of them. No, some method for connecting parties who wished to speak to one another had to be found and it is at this juncture of the telephone's career that a new contributor to the invention's success comes upon the scene. "Doing business at Number 342 Washington Street was a young New Yorker by the name of Edwin T. Holmes, who had charge of his father's burglar-alarm office. As all the electrical equipment he used was made at Williams's shop, he used frequently to go there and one day, when he entered, he came upon Charles Williams, the proprietor of the store, standing before a little box that rested on a shelf and shouting into it. Hearing Mr. Holmes's step, he glanced over his shoulder, met his visitor's astonished gaze, and laughed. "'For Heaven's sake, Williams, what have you got in that box?' demanded Mr. Holmes. "'Oh, this is what that fellow out there by Watson's bench, Mr. Bell, calls a telephone,' replied Mr. Williams. "'So that's the thing I have seen squibs in the paper about!' observed the burglar-alarm man with curiosity. "'Yes, he and Watson have been working at it for some time.' "Now Mr. Holmes knew Tom Watson well for the young electrician had done a great deal of work for him in the past; moreover, the New York man was a person who kept well abreast of the times and was always alert for novel ideas. Therefore quite naturally he became interested in the embryo enterprise and dropped into Williams's shop almost every day to see how the infant invention was progressing. In this way he met both Mr. Gardiner Hubbard and Mr. Thomas Saunders, who were Mr. Bell's financial sponsors. After Mr. Holmes had been a spectator of the telephone for some time, he remarked to Mr. Hubbard: "'If you succeed in getting two or three of those things to work and will lend them to me, I will show them to Boston.' "'Show them to Boston,' repeated Mr. Hubbard. 'How will you do that?' "'Well,' said Mr. Holmes, 'I have a Central Office down at Number 342 Washington Street from which I have individual wires running to most of the banks, many jeweler's shops, and other stores. I can ring a bell in a bank from my office and the bank can ring one to me in return. By using switches and giving a prearranged signal to the Exchange Bank, both of us could throw a switch which would put the telephones in circuit and we could talk together.' "After looking at Mr. Holmes for a moment with great surprise, Mr. Hubbard slapped him on the back and said, 'I will do it! Get your switches and other things ready.' "Of course Mr. Holmes was greatly elated to be the first one to show on his wires this wonderful new instrument and connect two or more parties through a Central Office. He immediately had a switchboard made (its actual size was five by thirty-six inches) through which he ran a few of his burglar-alarm circuits and by means of plugs he arranged so that he could throw the circuit from the burglar-alarm instruments to the telephone. He also had a shelf made to rest the telephones on and had others like it built at the Exchange National and the Hide and Leather banks. In a few days the telephones, numbered 6, 7, and 8, arrived and were quickly installed, and the marvellous exhibition opened. Soon two more instruments were added, one of which was placed in the banking house of Brewster, Bassett and Company and the other in the Shoe and Leather Bank. When the Williams shop was connected, it gave Mr. Holmes a working exchange of five connections, the first telephone exchange in history." "I'll bet they had some queer times with it," asserted Ted. "They did, indeed!" smiled Mr. Hazen. "The papers announced the event, although in very retiring type, and persons of every walk in life flocked to the Holmes office to see the wonder with their own eyes. So many came that Mr. Holmes had a long bench made so that visitors could sit down and watch the show. One day a cornetist played from the Holmes building so that the members of the Boston Stock Exchange, assembled at the office of Brewster, Bassett and Company, could hear the performance. Considering the innovation a great boon, the New York man secured another instrument and after meditating some time on whom he would bestow it he decided to install it in the Revere Bank, thinking the bank people would be delighted to be recipients of the favor. His burglar-alarm department had pass-keys to all the banks and therefore, when banking hours were over, he and one of his men obtained entrance and put the telephone in place. The following morning he had word that the president of the bank wished to see him and expecting to receive thanks for the happy little surprise he had given the official, he hurried to the bank. Instead of expressing gratitude, however, the president of the institution said in an injured tone: "'Mr. Holmes, what is that play toy you have taken the liberty of putting up out there in the banking room?' "'Why, that is what they are going to call a telephone,' explained Mr. Holmes. "'A telephone! What's a telephone?' inquired the president. "With enthusiasm the New Yorker carefully sketched in the new invention and told what could be done with it. "After he had finished he was greatly astonished to have the head of the bank reply with scorn: "'Mr. Holmes, you take that plaything out of my bank and don't ever take such liberties again.' "You may be sure the _plaything_ was quickly removed and the Revere Bank went on record as having the first telephone disconnection in the country. "Having exhibited the telephones for a couple of weeks, Mr. Holmes went to Mr. Hubbard and suggested that he would like to continue to carry on the exchange but he should like it put on a business basis. "'Have you any money?' asked Mr. Hubbard. "'Mighty little,' was the frank answer. "'Well, that's more than we have got,' Mr. Hubbard responded. 'However, if you have got enough money to do the business and build the exchange, we will rent you the telephones.' "By August, 1877, when Bell's patent was sixteen months' old, Casson's History tells us there were seven hundred and seventy-eight telephones in use and the Bell Telephone Association was formed. The organization was held together by an extremely simple agreement which gave Bell, Hubbard, and Saunders a three-tenths' interest apiece in the patents and Watson one-tenth. The business possessed no capital, as there was none to be had; and these four men at that time had an absolute monopoly of the telephone business,--and everybody else was quite willing they should have. "In addition to these four associates was Charles Williams, who had from the first been a believer in the venture, and Mr. Holmes who built the first telephone exchange with his own money, and had about seven hundred of the seven hundred and seventy-eight instruments on his wires. Mr. Robert W. Devonshire joined the others in August, 1877, as bookkeeper and general secretary and has since become an official in the American Telephone and Telegraph Company. "Mr. Holmes rented the telephones for ten dollars a year and through his exchange was the first practical man who had the temerity to offer telephone service for sale. It was the arrival of a new idea in the business world. "Now the business world is not a tranquil place and as soon as the new invention began to prosper, every sort of difficulty beset its path. "There were those who denied that Mr. Bell had been first in the field with the telephone idea, and they began to contest his right to the patents. Other telephone companies sprang up and began to compete with the rugged-hearted pioneers who had launched the industry. Lawsuits followed and for years Mr. Bell's days were one continual fight to maintain his claims and keep others from wresting his hard-earned prosperity from him. But in time smoother waters were reached and now Alexander Graham Bell has been universally conceded to be the inventor of this marvel without which we of the present should scarcely know how to get on." "I don't believe we could live without telephones now, do you?" remarked Laurie thoughtfully. "Oh, I suppose we could keep alive," laughed Mr. Hazen, "but I am afraid our present order of civilization would have to be changed a good deal. We scarcely realize what a part the telephone plays in almost everything we attempt to do. Certainly the invention helps to speed up our existence; and, convenient as it is, I sometimes am ungrateful enough to wonder whether we should not be a less highly strung and nervous nation without it. However that may be, the telephone is here, and here to stay, and you now have a pretty clear idea of its early history. How from these slender beginnings the industry spread until it spanned continents and circled the globe, you can easily read elsewhere. Yet mighty as this factor has become in the business world, it is not from this angle of its greatness that I like best to view it. I would rather think of the lives it has saved; the good news it has often borne; the misunderstandings it has prevented; the better unity it has promoted among all peoples. Just as the railroad was a gigantic agent in bringing North, South, East, and West closer together, so the telephone has helped to make our vast country, with its many diverse elements, 'one nation, indivisible.'" CHAPTER XII CONSPIRATORS With September a tint of scarlet crept into the foliage bordering the little creeks that stole from the river into the Aldercliffe meadows; tangles of goldenrod and purple asters breathed of autumn, and the mornings were now too chilly for a swim. Had it not been for the great fireplace the shack would not have been livable. For the first time both Ted and Laurie realized that the summer they had each enjoyed so heartily was at an end and they were face to face with a different phase of life. The harvest, with its horde of vegetables and fruit, had been gathered into the yawning barns and cellars and the earth that had given so patiently of its increase had earned the right to lay fallow until the planting of another spring. Ted's work was done. He had helped deposit the last barrel of ruddy apples, the last golden pumpkins within doors, and now he had nothing more to do but to pack up his possessions preparatory to returning to Freeman's Falls, there to rejoin his family and continue his studies. Once the thought that the drudgery of summer was over would have been a delightful one. Why, he could remember the exultation with which he had burned the last cornstalks at the end of the season when at home in Vermont. The ceremony had been a rite of hilarious rejoicing. But this year, strange to say, a dull sadness stole over him whenever he looked upon the devastated gardens and the reaches of bare brown earth. There was nothing to keep him longer either at Aldercliffe or Pine Lea. His work henceforth lay at school. It was strange that a little sigh accompanied the thought for had he not always looked forward to this very prospect? What was the matter now? Was not studying the thing he had longed to be free to do? Why this regret and depression? And why was his own vague sadness reflected in Laurie's eyes and in those of Mr. Hazen? Summer could not last forever; it was childish to ask that it should. They all had known from the beginning that these days of companionship must slip away and come to an end. And yet the end had come so quickly. Why, it had scarcely been midsummer before the twilight had deepened and the days mellowed into autumn. Well, they had held many happy, happy hours for Ted, at least. Never had he dreamed of such pleasures. He had enjoyed his work, constant though it had been, and had come to cherish as much pride in the gardens of Aldercliffe and Pine Lea, in the vast crops of hay that bulged from the barn lofts, as if they had been his own. And when working hours were over there was Laurie Fernald and the new and pleasant friendship that existed between them. As Ted began to drag out from beneath his bunk the empty wooden boxes he purposed to pack his books in, his heart sank. Soon the cosy house in which he had passed so many perfect hours would be quite denuded. Frosts would nip the flowers nodding in a final glory of color outside the windows; the telephone would be disconnected; his belongings would once more be crowded into the stuffy little flat at home; and the door of the camp on the river's edge would be tightly locked on a deserted paradise. Of course, everything had to come to an end some time and often when he had been weeding long, and what seemed interminable rows of seedlings and had been making only feeble progress at the task, the thought that termination of his task was an ultimate certainty had been a consolation mighty and sustaining. Such an uninteresting undertaking could not last forever, he told himself over and over again; nothing ever did. And now with ironic conformity to law, his philosophy had turned on him, demonstrating beyond cavil that not only did the things one longed to be free of come to a sure finality but so did those one pined to have linger. Although night was approaching, too intent had he been on his reveries to notice that the room was in darkness. How still everything was! That was the way the little hut would be after he was gone,--cold, dark, and silent. He wondered as he sat there whether he should ever come back. Would the Fernalds want him next season and again offer him the boathouse for a home? They had said nothing about it but if he thought he was to return another summer it would not be so hard to go now. It was leaving forever that saddened him. He must have remained immovable there in the twilight for a much longer time than he realized; and perhaps he would have sat there even longer had not a sound startled him into breathless attention. It was the rhythmic stroke of a canoe paddle and as it came nearer it was intermingled with the whispers of muffled voices. Possibly he might have thought nothing of the happening had there not been a note of tense caution in the words that came to his ear. Who could be navigating the river at this hour of the night? Surely not pleasure-seekers, for it was very cold and an approaching storm had clouded in the sky until it had become a dome of velvet blackness. Whoever was venturing out upon the river must either know the stream very well or be reckless of his own safety. Ted did not move but listened intently. "Let's take a chance and land," he heard a thick voice murmur. "The boy has evidently either gone to bed or he isn't here. Whichever the case, he can do us no harm and I'm not for risking the river any farther. It's black as midnight. We might get into the current and have trouble." "What's the sense of running our heads into a noose by landing?" objected a second speaker. "We can't talk here--that's nonsense." "I tell you the boy isn't in the hut," retorted his comrade. "I remember now that I heard he was going back to the Falls to school. Likely he has gone already. In any case we can try the door and examine the windows; if the place is locked, we shall be sure he is not here. And should it prove to be inhabited, we can easy hatch up some excuse for coming. He'll be none the wiser. Even if he should be here," added the man after a pause, "he is probably asleep. After a hard day's work a boy his age sleeps like a log. There'll be no waking him, so don't fret. Come! Let's steer for the float." "But I----" "Great Heavens, Cronin! We've got to take some chances. You're not getting cold feet so soon, are you?" burst out the other scornfully. "N--o! Of course not," his companion declared with forced bravado. "But I don't like taking needless risks. The boy might be awake and hear us." "What if he does? Haven't I told you I will invent some yarn to put him off the scent? He wouldn't be suspecting mischief, anyhow. I tell you I'm not going drifting round this river in the dark any longer. Next thing we know we may hit a snag and upset." "But you insisted on coming." "I know I did," snapped the sharp voice. "What chance had we to talk in a crowded boarding-house whose very walls had ears? Or on the village streets? I knew the river would have no listeners and you see I was right; it hasn't. But I did expect there would be a trifle more light. It is like ink, isn't it? You can't see your hand before your face." "I don't believe we could find the float even if we tried for it," piped his friend with malicious satisfaction. "Find it? Of course we can. I've traveled this river too many times to get lost on it. I know every inch of the stream." "But aren't there boats at the landing?" "Oh, they've been hauled in for the season long ago. I know that to be a fact." "Then I guess young Turner must have gone." "That's what I've been trying to tell you for the last half-hour," asserted the other voice with high-pitched irritation. "Why waste all this time? Let's land, talk things over, lay our plans, and be getting back to Freeman's Falls. We mustn't be seen returning to the town together too late for it might arouse suspicion." "You're right there." "Then go ahead and paddle for the landing. I'll steer. Just have your hand out so we won't bump." The lapping of the paddles came nearer and nearer. Then there was a crash as the nose of the canoe struck the float. "You darned idiot, Cronin! Why didn't you fend her off as I told you to?" "I couldn't see. I----" "Hush!" A moment of breathless silence followed and then there was a derisive laugh. "I told you the boy wasn't here," one of the men declared aloud. "If he had been he would have had his head out the window by now. We've made noise enough to wake the dead." "But he may be here for all that," cautioned the other speaker. "Don't talk so loud." "Nonsense!" his comrade retorted without lowering his tone. "I tell you the boy has gone back home and the hut is as empty as a last year's bird's nest. I'll stake my oath on it. The place is shut and locked tight as a drum. You'll see I'm right presently." Instantly Ted's brain was alert. The door was locked, that he knew, for when he came in he had bolted it for the night. One window, however, was open and he dared not attempt to close it lest he make some betraying sound; and even were he able to shut it noiselessly he reflected that the procedure would be an unwise one since it would cut him off from hearing the conversation. No, he must keep perfectly still and trust that his nocturnal visitors would not make too thorough an investigation of the premises. To judge from the scuffling of feet outside, both of them had now alighted from the canoe and were approaching the door. Soon he heard a hand fumbling with the latch and afterward came a heavy knock. Slipping breathlessly from his chair he crouched upon the floor, great beads of perspiration starting out on his forehead. "The door is locked, as I told you," he heard some one mutter. "He may be asleep." "We can soon make sure. Ah, there! Turner! Turner!" Once more a series of blows descended upon the wooden panel. "Does that convince you, Cronin?" "Y--e--s," owned Cronin reluctantly. "I guess he's gone." "Of course he's gone! Come, brace up, can't you?" urged his companion. "Where's your backbone?" "I'm not afraid." "Tell that to the marines! You're timid and jumpy as a girl. How are we ever to put this thing over if you don't pull yourself together? I might as well have a baby to help me," sneered the gruff voice. "Don't be so hard on me, Alf," whined his comrade. "I ain't done nothin'. Ain't I right here and ready?" "You're here, all right," snarled the first speaker, "but whether you're ready or not is another matter. Now I'm going to give you a last chance to pull out. Do you want to go ahead or don't you? It's no good for us to be laying plans if you are going to be weak-kneed at the end and balk at carrying them out. Do you mean to stand by me and see this thing to a finish or don't you?" "I--sure I do!" "Cross your heart?" "Cross my heart!" This time the words echoed with more positiveness. "You're not going to back out or squeal?" his pal persisted. "Why, Alf, how can you----" "Because I've got to be sure before I stir another inch." "But ain't I told you over and over again that I----" "I don't trust you." "What makes you so hard on a feller, Alf?" whimpered Cronin. "I haven't been mixed up in as many of these jobs as you have and is it surprising that I'm a mite nervous? It's no sign that I'm crawling." "You're ready to stick it out, then?" "Sure!" There was another pause. "Well, let me just tell you this, Jim Cronin. If you swear to stand by me and don't do it, your miserable life won't be worth a farthing--understand? I'll wring your neck, wring it good and thorough. I'm not afraid to do it and I will. You know that, don't you?" "Yes." The terror-stricken monosyllable made it perfectly apparent that Cronin did know. "Then suppose we get down to hard tacks," asserted his companion, the note of fierceness suddenly dying out of his tone. "Come and sit down and we'll plan the thing from start to finish. We may as well be comfortable while we talk. There's no extra charge for sitting." As Ted bent to put his ear to the crack of the door, the thud of a heavy body jarred the shack. "Jove!" he heard Cronin cry. "The ground is some way down, ain't it?" "And it's none to soft at that," came grimly from his comrade, as a second person slumped upon the planks outside. Somebody drew a long breath and while the men were making themselves more comfortable on the float Ted waited expectantly in the darkness. CHAPTER XIII WHAT TED HEARD "Now the question is which way are we going to get the biggest results," Alf began, when they were both comfortably settled with their backs to the door. "That must be the thing that governs us--that, and the sacrifice of as few lives as possible. Not _their_ lives, of course. I don't care a curse for the Fernalds; the more of them that go sky-high the better, in my estimation. It's the men I mean, our own people. Some of them will have to die, I know that. It's unavoidable, since the factories are never empty. Even when no night shifts are working, there are always watchmen and engineers on the job. But fortunately just now, owing to the dull season, there are no night gangs on duty. If we decide on the mills it can be done at night; if on the Fernalds themselves, why we can set the bombs when we are sure that they are in their houses." Ted bit his lips to suppress the sudden exclamation of horror that rose to them. He must not cry out, he told himself. Terrible as were the words he heard, unbelievable as they seemed, if he were to be of any help at all he must know the entire plot. Therefore he listened dumbly, struggling to still the beating of his heart. For a moment there was no response from Cronin. "Come, Jim, don't sit there like a graven image!" the leader of the proposed expedition exclaimed impatiently. "Haven't you a tongue in your head? What's your idea? Out with it. I'm not going to shoulder all the job." The man called Cronin cleared his throat. "As I see it, we gain nothing by blowing up the Fernald houses," answered he deliberately. "So long as the mills remain, their income is sure. After they're gone, the young one will just rebuild and go on wringing money out of the people as his father and grandfather are doing." "But we mean to get him, too." A murmured protest came from Cronin. "I'm not for injuring that poor, unlucky lad," asserted he. "He's nothing but a cripple who can't help himself. It would be like killing a baby." "Nonsense! What a sentimental milksop you are, Jim!" Alf cut in. "You can't go letting your feelings run away with you like that, old man. I'm sorry for the young chap, too. He's the most decent one of the lot. But that isn't the point. He's a Fernald and because he is----" "But he isn't to blame for that, is he?" "You make me tired, Cronin, with all this cry-baby stuff!" Alf ejaculated. "You've simply got to cut it out--shut your ears to it--if we are ever to accomplish anything. You can't let your sympathies run away with you like this." "I ain't letting my sympathies run away with me," objected Cronin, in a surly tone. "And I'm no milksop, either. But I won't be a party to harming that unfortunate Mr. Laurie and you may as well understand that at the outset. I'm willing to do my share in blowing the Fernald mills higher than a kite, and the two Fernalds with 'em; or I'll blow the two Fernalds to glory in their beds. I could do it without turning a hair. But to injure that helpless boy of theirs I can't and won't. That would be too low-down a deed for me, bad as I am. He hasn't the show the others have. They can fend for themselves." "You make me sick!" replied Alf scornfully. "Why, you might as well throw up the whole job as to only half do it. What use will it be to take the old men of the family if the young one still lives on?" "I ain't going to argue with you, Alf," responded Cronin stubbornly. "If I were to talk all night you likely would never see my point. But there I stand and you can take it or leave it. If you want to go on on these terms, well and good; if not, I wash my hands of the whole affair and you can find somebody else to help you." "Of course I can't find somebody else," was the exasperated retort. "You know that well enough. Do you suppose I would go on with a scheme like this and leave you wandering round to blab broadcast whatever you thought fit?" "I shouldn't blab, Alf," declared Cronin. "You could trust me to hold my tongue and not peach on a pal. I should just pull out, that's all. I warn you, though, that if our ways parted and you went yours, I should do what I could to keep Mr. Laurie out of your path." "You'd try the patience of Job, Cronin." "I'm sorry." "No, you're not," snarled Alf. "You're just doing this whole thing to be cussed. You know you've got me where I can't stir hand or foot. I was a fool ever to have got mixed up with such a white-livered, puling baby. I might have known you hadn't an ounce of sand." "Take care, Sullivan," cautioned Cronin in a low, tense voice. "But hang it all--why do you want to balk and torment me so?" "I ain't balking and tormenting you." "Yes, you are. You're just pulling the other way from sheer contrariness. Why can't you be decent and come across?" "Haven't I been decent?" Cronin answered. "Haven't I fallen in with every idea you've suggested? You've had your way fully and freely. I haven't stood out for a single thing but this, have I?" "N--o. But----" "Well, why not give in and let me have this one thing as I want it? It don't amount to much, one way or the other. The boy is sickly and isn't likely to live long at best." "But I can't for the life of me see why you should be so keen on sparing him. What is he to you?" Cronin hesitated; then in a very low voice he said: "Once, two years ago, my little kid got out of the yard and unbeknown to his mother wandered down by the river. We hunted high and low for him and were well-nigh crazy, for he's all the child we have, you know. It seems Mr. Laurie was riding along the shore in his automobile and he spied the baby creeping out on the thin ice. He stopped his car and called to the little one and coaxed him back until the chauffeur could get to him and lift him aboard the car. Then they fetched the child to the village, hunted up where he lived, and brought him home to his mother. I--I've never forgotten it and I shan't." "That was mighty decent of Mr. Laurie--mighty decent," Sullivan admitted slowly. "I've got a kid at home myself." For a few moments neither man spoke; then Sullivan continued in quick, brisk fashion, as if he were trying to banish some reverie that plagued him: "Well, have your way. We'll leave Mr. Laurie out of this altogether." "Thank you, Alf." Sullivan paid no heed to the interruption. "Now let's can all this twaddle and get down to work," he said sharply. "We've wasted too much time squabbling over that miserable cripple. Let's brace up and make our plans. You are for destroying the mills, eh?" "It's the only thing that will be any use, it seems to me," Cronin replied. "If the mills are blown up, it will not only serve as a warning to the Fernalds but it will mean the loss of a big lot of money. They will rebuild, of course, but it will take time, and in the interval everything will be at a standstill." "It will throw several hundred men out of work," Sullivan objected. "That can't be helped," retorted Cronin. "They will get out at least with their lives and will be almighty thankful for that. They can get other jobs, I guess. But even if they are out of work, I figure some of them won't be so sorry to see the Fernalds get what's coming to them," chuckled Cronin. "You're right there, Jim!" "I'll bet I am!" cried Cronin. "Then your notion would be to plant time bombs at the factories so they will go off in the night?" "Yes," confessed Cronin, a shadow of regret in his tone. "That will carry off only a few watchmen and engineers. Mighty tough luck for them." "It can't be helped," Sullivan said ruthlessly. "You can't expect to carry through a thing of this sort without some sacrifice. All we can do is to believe that the end justifies the means. It's a case of the greatest good to the greatest number." "I--suppose--so." "Well, then, why hesitate?" "I ain't hesitating," announced Cronin quickly. "I just happened to remember Maguire. He's one of the night watchmen at the upper mill and a friend of mine." "But we can't remember him, Cronin," Sullivan burst out. "It is unlucky that he chances to be on duty, of course; but that is his misfortune. We'd spare him if we could." "I know, I know," Cronin said. "It's a pitiless business." Then, as if his last feeble compunction vanished with the words, he added, "It's to be the mills, then." "Yes. We seem to be agreed on that," Sullivan replied eagerly. "I have everything ready and I don't see why we can't go right ahead to-night and plant the machines with their fuses timed for early morning. I guess we can sneak into the factories all right--you to the upper mill and I to the lower. If you get caught you can say you are hunting for Maguire; and if I do--well, I must trust to my wits to invent a story. But they won't catch me. I've never been caught yet, and I have handled a number of bigger jobs than this one," concluded he with pride. "Anything more you want to say to me?" asked Cronin. "No, I guess not. I don't believe I need to hand you any advice. Just stiffen up, that's all. Anything you want to say to me?" "No. I shan't worry my head about you, you old fox. You're too much of a master hand," Cronin returned, with an inflection that sounded like a grin. "I imagine you can hold up your end." "I rather imagine I can," drawled Sullivan. "Then if there's nothing more to be said, I move we start back to town. It must be late," Cronin asserted. "It's black enough to be midnight," grumbled Sullivan. "We'd best go directly to our houses--I to mine and you to yours. The explosives and bombs I'll pack into two grips. Yours I'll hide in your back yard underneath that boat. How'll that be?" "O. K." "You've got it straight in your head what you are to do?" "Yes." "And I can count on you?" "Sure!" "Then let's be off." There was a splash as the canoe slipped into the water and afterward Ted heard the regular dip of the paddles as the craft moved away. He listened until the sound became imperceptible and when he was certain that the conspirators were well out of earshot he sped to the telephone and called up the police station at Freeman's Falls. It did not take long for him to hurriedly repeat to an officer what he had heard. Afterward, in order to make caution doubly sure, he called up the mills and got his old friend Maguire at the other end of the line. It was not until all this had been done and he could do no more that he sank limply down on the couch and stared into the darkness. Now that everything was over he found that he was shaking like a leaf. His hands were icy cold and he quivered in every muscle of his body. It was useless for him to try to sleep; he was far too excited and worried for that. Therefore he lay rigidly on his bunk, thinking and waiting for--he knew not what. It might have been an hour later that he was aroused from a doze by the sharp reverberation of the telephone bell. Dizzily he sprang to his feet and stood stupid and inert in the middle of the floor. Again the signal rang and this time he was broad awake. He rushed forward to grasp the receiver. "Turner? Ted Turner?" "Yes, sir." "This is the police station at Freeman's Falls. We have your men--both of them--and the goods on them. They are safe and sound under lock and key. I just thought you might like to know it. We shall want to see you in the morning. You've done a good night's work, young one. The State Police have been after these fellows for two years. Sullivan has a record for deeds of this sort. Mighty lucky we got a line on him this time before he did any mischief." "It was." "That's all, thanks to you, kid. I advise you to go to bed now and to sleep. I'll hunt you up to-morrow. I'll bet the Fernalds will, too. They owe you something." CHAPTER XIV THE FERNALDS WIN THEIR POINT The trial of Alf Sullivan and Jim Cronin was one of the most spectacular and thrilling events Freeman's Falls had ever witnessed. That two such notorious criminals should have been captured through the efforts of a young boy was almost inconceivable to the police, especially to the State detectives whom they had continually outwitted. And yet here they were in the dock and the town officers made not the slightest pretense that any part of the glory of their apprehension belonged to them. To Ted Turner's prompt action, and to that alone, the triumph was due. In consequence the boy became the hero of the village. He had always been a favorite with both young and old, for every one liked his father, and it followed that they liked his father's son. Now, however, they had greater cause to admire that son for his own sake and cherish toward him the warmest gratitude. Many a man and woman reflected that it was this slender boy who had stood between them and a calamity almost too horrible to be believed; and as a result their gratitude was tremendous. And if the townsfolk were sensible of this great obligation how much more keenly alive to it were the Fernalds whose property had been thus menaced. "You have topped one service with another, Ted," Mr. Lawrence Fernald declared. "We do not see how we are ever to thank you. Come, there must be something that you would like--some wish you would be happy to have gratified. Tell us what it is and perhaps we can act as magicians and make it come true." "Yes," pleaded Mr. Clarence Fernald, "speak out, Ted. Do not hesitate. Remember you have done us a favor the magnitude of which can never be measured and which we can never repay." "But I do not want to be paid, sir," the lad answered. "I am quite as thankful as you that the wretches who purposed harm were caught before they had had opportunity to destroy either life or property. Certainly that is reward enough." "It _is_ a reward in its way," the elder Mr. Fernald asserted. "The thought that it was you who were the savior of an entire community will bring you happiness as long as you live. Nevertheless we should like to give you something more tangible than pleasant thoughts. We want you to have something by which to remember this marvelous escape from tragedy. Deep down in your heart there must be some wish you cherish. If you knew the satisfaction it would give us to gratify it, I am sure you would not be so reluctant to express it." Ted colored, and after hesitating an instant, shyly replied: "Since you are both so kind and really seem to wish to know, there is something I should like." "Name it!" the Fernalds cried in unison. "I should like to feel I can return to the shack next summer," the boy remarked timidly. "You see, I have become very fond of Aldercliffe and Pine Lea, fond of Laurie, of Mr. Hazen, and of the little hut. I have felt far more sorry than perhaps you realize to go away from here." His voice quivered. "You poor youngster!" Mr. Clarence exclaimed. "Why in the name of goodness didn't you say so? There is no more need of your leaving this place than there is of my going, or Laurie. We ought to have sensed your feeling and seen to it that other plans were made long ago. Indeed, you shall come back to your little riverside abode next summer--never fear! And as for Aldercliffe, Pine Lea, Laurie and all the rest of it, you shall not be parted from any of them." "But I must go back to school now, sir." "What's the matter with your staying on at Pine Lea and having your lessons with Laurie and Mr. Hazen instead?" "Oh--why----" "Should you like to?" "Oh, Mr. Fernald, it would be----" Laurie's father laughed. "I guess we do not need an answer to that question," Grandfather Fernald remarked, smiling. "His face tells the tale." "Then the thing is as good as done," Mr. Clarence announced. "Hazen will be as set up as an old hen to have two chicks. He likes you, Ted." "And well he may," growled Grandfather Fernald. "But for Ted's prayers and pleas he would not now be here." "Yes, Hazen will be much pleased," reiterated Mr. Clarence Fernald, ignoring his father's comment. "As for Laurie--I wonder we never thought of all this before. It is no more work to teach two boys than one, and in the meantime each will act as a stimulus for the other. The spur of rivalry will be a splendid incentive for Laurie, to say nothing of the joy he will take in your companionship. He needs young people about him. It is a great scheme, a great scheme!" mused Mr. Fernald, rubbing his hands with increasing satisfaction as one advantage of the arrangement after another rotated through his mind. "If only my father does not object," murmured Ted. "Object! Object!" blustered Grandfather Fernald. "And why, pray, should he object?" That a man of Mr. Turner's station in life should view the plan with anything but pride and complacency was evidently a new thought to the financier. "Why, sir, my father and sisters are very fond of me and may not wish to have me remain longer away from home. They have missed me a lot this summer, I know that. You see I am the youngest one, the only boy." "Humph!" interpolated the elder Mr. Fernald. "In spite of the fact that we are crowded at home and too busy to see much of one another, Father likes to feel I'm around," continued Ted. "I--suppose--so," came slowly from the old gentleman. "I am sure I can fix all that," asserted Mr. Clarence Fernald briskly. "I will see your father and sisters myself, and I feel sure they will not stand in the way of your getting a fine education when it is offered you--that is, if they care as much for you as you say they do. On the contrary, they will be the first persons to realize that such a plan is greatly to your advantage." "It is going to be almightily to your advantage," Mr. Lawrence Fernald added. "Who can tell where it all may lead? If you do well at your studies, perhaps it may mean college some day, and a big, well-paid job afterward." Ted's eyes shone. "Would you like to go to college if you could?" persisted the elder man. "You bet I would--I mean yes, sir." The old gentleman chuckled at the fervor of the reply. "Well, well," said he, "time must decide all that. First lay a good foundation. You cannot build anything worth building without something to build upon. You get your cellar dug and we will then see what we will put on top of it." With this parting remark he and his son moved away. When the project was laid before Laurie, his delight knew no bounds. To have Ted come and live at Pine Lea for the winter, what a lark! Think of having some one to read and study with every day! Nothing could be jollier! And Mr. Hazen was every whit as pleased. "It is the very thing!" he exclaimed to Laurie's father. "Ted will not be the least trouble. He is a fine student and it will be a satisfaction to work with him. Besides, unless I greatly miss my guess, he will cheer Laurie on to much larger accomplishments. Ted's influence has never been anything but good." And what said Laurie's mother? "It is splendid, Clarence, splendid! We can refurnish that extra room that adjoins Laurie's suite and let Mr. Hazen and the boys have that entire wing of the house. Nothing could be simpler. I shall be glad to have Ted here. Not only is he a fine boy but he has proved himself a good friend to us all. If we can do anything for him, we certainly should do it. The lad has had none too easy a time in this world." Yes, all went well with the plan so far as the Fernalds were concerned; but the Turners--ah, there was the stumbling block! "It's no doubt a fine thing you're offering to do for my son," Ted's father replied to Mr. Clarence Fernald, "and I assure you I am not unmindful of your kindness; but you see he is our only boy and when he isn't here whistling round the house we miss him. 'Tain't as if we had him at home during his vacation. If he goes up to your place to work summers and stays there winters as well, we shall scarcely see him at all. All we have had of him this last year was an occasional teatime visit. Folks don't like having their children go out from the family roof so young." "But, Father," put in Nancy, "think what such a chance as this will mean to Ted. You yourself have said over and over again that there was nothing like having an education." "I know it," mused the man. "There's nothing can equal knowing something. I never did and look where I've landed. I'll never go ahead none. But I want it to be different with my boy. He's going to have some stock in trade in the way of training for life. It will be a kind of capital nothing can sweep away. As I figure it, it will be a sure investment--that is, if the boy has any stuff in him." "An education is a pretty solid investment," agreed the elder Mr. Fernald, "and you are wise to recognize its value, Mr. Turner. To plunge into life without such a weapon is like entering battle without a sword. I know, for I have tried it." "Have you indeed, sir?" Grandfather Fernald nodded. "I was brought up on a Vermont farm when I was a boy." "You don't say so! Well, well!" "Yes, I never had much schooling," went on the old man. "Of course I picked up a lot of practical knowledge, as a boy will; and in some ways it has not been so bad. But it was a pretty mixed-up lot of stuff and I have been all my life sorting it out and putting it in order. I sometimes wonder when I think things over that I got ahead at all; it was more happen than anything else, I guess." "The Vermonters have good heads on their shoulders," Mr. Turner remarked. "Oh, you can't beat the Green Mountain State," laughed the senior Mr. Fernald, unbending into cordiality in the face of a common interest. "Still, when it came to bringing up my boy I felt as you do. I wasn't satisfied to have him get nothing more than I had. So I sent him to college and gave him all the education I never got myself. It has stood him in good stead, too, and I've lived to be proud of what he's done with it." "And well you may be, sir," Mr. Turner observed. Mr. Clarence Fernald flushed in the face of these plaudits and cut the conversation short by saying: "It is that kind of an education that we want to give your boy, Mr. Turner. We like the youngster and believe he has promise of something fine. We should like to prepare him for college or some technical school and send him through it. He has quite a pronounced bent for science and given the proper opportunities he might develop into something beyond the ordinary rank and file." "Do you think so, sir?" asked Mr. Turner, glowing with pleasure. "Well, I don't know but that he has a sort of knack with wire, nails, and queer machinery. He has tinkered with such things since he was a little lad. Of late he has been fussing round with electricity and scaring us all to death here at home. His sisters were always expecting he'd meet his end or blow up the house with some claptraption he'd put together." Nancy blushed; then added, with a shy glance toward the Fernalds: "They say down at the school that Ted is quite handy with telephones and such things." "Mr. Hazen, my son's tutor, thinks your brother has a knowledge of electricity far beyond his years," replied Mr. Clarence Fernald. "That is why it seems a pity his talents in that direction should not be cultivated. Who knows but he may be an embryo genius? You never can tell what may be inside a child." "You're right there, sir," Mr. Turner assented cordially. Then after a moment of thought, he continued, "Likely an education such as you are figuring on would cost a mint of money." The Fernalds, both father and son, smiled at the naïve comment. "Well--yes," confessed Mr. Clarence slowly. "It would cost something." "A whole lot?" "If you wanted the best." Mr. Turner scratched his head. "I'm afraid I couldn't swing it," declared he, regret in his tone. "But we are offering to do this for you," put in Grandfather Fernald. "I know you are, sir; I know you are and I'm grateful," Ted's father answered. "But if I could manage it myself, I'd----" "Come, Mr. Turner, I beg you won't say that," interrupted the elder Mr. Fernald. "Think what we owe to your son. Why, we never in all the world can repay what he has done for us. This is no favor. We are simply paying our debts. You like to pay your bills, don't you?" "Indeed I do, sir!" was the hearty reply. "There's no happier moment than the one when I take my pay envelope and go to square up what I owe. True, I don't run up many bills; still, there is not always money enough on hand to make both ends meet without depending some on credit." "How much do you get in the shipping room?" "Eighty dollars a month, sir." "And your daughters are working?" "They are in the spinning mills." Mr. Fernald glanced about over the little room. Although scrupulously neat, it was quite apparent that the apartment was far too crowded for comfort. The furnishings also bespoke frugality in the extreme. It was not necessary to be told that the Turners' life was a close arithmetical problem. "Your family stand by us loyally," observed the financier. "We have your mills to thank for our daily bread, sir," Mr. Turner answered. "And your boy--if he does not go on with his studies shall you have him enter the factories?" Mr. Turner squared his shoulders with a swift gesture of protest. "No, sir--not if I can help it!" he burst out. Then as if he suddenly sensed his discourtesy, he added, "I beg your pardon, gentlemen. I wasn't thinking who I was talking to. It isn't that I do not like the mills. It's only that there is so little chance for the lad to get ahead there. I wouldn't want the boy to spend his life grubbing away as I have." "And yet you are denying him the chance to better himself." "I am kinder going round in a circle, ain't I?" returned Mr. Turner gently. "Like as not it is hard for you to understand how I feel. It's only that you hate to let somebody else do for your children. It seems like charity." "Charity! Charity--when we owe the life of our boy, the lives of many of our workmen, the safety of our mills to your son?" ejaculated Mr. Clarence Fernald with unmistakable sincerity. "When you pile it up that way it does sound like a pretty big debt, doesn't it?" mused Mr. Turner. "Of course it's a big debt--it is a tremendous one. Now try, Mr. Turner, and see our point of view. We want to take our envelope in our hands and although we have not fortune enough in the world to wipe out all we owe, we wish to pay part of it, at least. No matter how much we may be able to do for Ted in the future, we shall never be paying in full all that he has done for us. Much of his service we must accept as an obligation and give in return for it nothing but gratitude and affection. But if you will grant us the privilege of doing this little, it will give us the greatest pleasure." If any one had told the stately Mr. Lawrence Fernald weeks before that he would be in the home of one of his workmen, pleading for a favor, he would probably have shrugged his shoulders and laughed; and even Mr. Clarence Fernald, who was less of an aristocrat than his father, would doubtless have questioned a prediction of his being obliged actually to implore one of the men in his employ to accept a benefaction from him. Yet here they both were, almost upon their knees, theoretically, before this self-respecting artisan. In the face of such entreaty who could have remained obdurate? Certainly not Mr. Turner who in spite of his pride was the kindest-hearted creature alive. "Well, you shall have your way, gentlemen," he at length replied, "Ted shall stay on at Pine Lea, since you wish it, and you shall plan his education as you think best. I know little of such matters and feel sure the problem is better in your hands than mine. I know you will work for the boy's good. And I beg you won't think me ungrateful because I have hesitated to accept your offer. We all have our scruples and I have mine. But now that I have put them in the background, I shall take whole-heartedly what you give and be most thankful for it." Thus did the Fernalds win their point. Nevertheless they came away from the Turner's humble home with a consciousness that instead of bestowing a favor, as they had expected to do, they had really received one. Perhaps they did not respect Ted's father the less because of his reluctance to take the splendid gift they had put within his reach. They themselves were proud men and they had a sympathy for the pride of others. There could be no question that the interview had furnished both of them with food for thought for as they drove home in their great touring car they did not speak immediately. By and by, however, Grandfather Fernald observed: "Don't you think, Clarence, Turner's pay should be increased? Eighty dollars isn't much to keep a roof over one's head and feed a family of three persons." "I have been thinking that, too," returned his son. "They tell me he is a very faithful workman and he has been here long enough to have earned a substantial increase in wages. I don't see why I never got round to doing something for him before. The fellow was probably too proud to ask for more money and unless some kick comes to me those things slip my mind. I'll see right away what can be done." There was a pause and then the senior Mr. Fernald spoke again: "Do you ever feel that we ought to do something about furnishing better quarters for the men?" he asked. "I have had the matter on my conscience for months. Look at that tenement of the Turners! It is old, out of date, crowded and stuffy. There isn't a ray of sunshine in it. It's a disgrace to herd a family into such a place. And I suppose there are ever so many others like it in Freeman's Falls." "I'm afraid there are, Father." "I don't like the idea of it," growled old Mr. Fernald. "The houses all look well enough until one goes inside. But they're terrible, terrible! Why, they are actually depressing. I haven't shaken off the gloom of that room yet. We own land enough on the other side of the river. Why couldn't we build a handsome bridge and then develop that unused area by putting up some decent houses for our people? It would increase the value of the property and at the same time improve the living conditions of our employees. What do you say to the notion?" "I am ready to go in on any such scheme!" cried Mr. Clarence Fernald heartily. "I'd like nothing better. I have always wanted to take up the matter with you; but I fancied from something you said once when I suggested it that you----" "I didn't realize what those houses down along the water front were like," interrupted Grandfather Fernald. "Ugh! At least sunshine does not cost money. We must see that our people get more of it." CHAPTER XV WHAT CAME OF THE PLOT The Fernalds were as good as their word. All winter long father, son, and grandson worked at the scheme for the new cottages and by New Year, with the assistance of an architect, they had on paper plans for a model village to be built on the opposite side of the river as soon as the weather permitted. The houses were gems of careful thought, no two of them being alike. Nevertheless, although each tiny domain was individual in design, a general uniformity of construction existed between them which resulted in a delightfully harmonious ensemble. The entire Fernald family was enthusiastic over the project. It was the chief topic of conversation both at Aldercliffe and at Pine Lea. Rolls of blue prints littered office and library table and cluttered the bureaus, chairs, and even the pockets of the elder men of each household. "We are going to make a little Normandy on the other shore of the river before we have done with it," asserted Grandfather Fernald to Laurie. "It will be as pretty a settlement as one would wish to see. I mean, too, to build coöperative stores, a clubhouse, and a theater; perhaps I may even go farther and put up a chapel. I have gone clean daft over the notion of a model village and since I am started I may as well be hung for a sheep as a lamb. I do not believe we shall be sinking our money, either, for in addition to bettering the living conditions of our men I feel we shall also draw to the locality a finer class of working people. This will boom our section of the country and should make property here more valuable. But even if it doesn't work out that way, I shall take pride in the proposed village. I have always insisted that our mills be spotless and up to date and the fact that they have been has been a source of great gratification. Now I shall carry that idea farther and see that the new settlement comes up to our standards. I have gone over and over the plans to see if in any way they can be bettered; suppose you and I look at them together once more. Some new inspiration may come to us--something that will be an improvement." Patiently and for the twentieth time Laurie examined the blue prints while his grandfather volubly explained just where each building of the many was to stand. "This little park, with a fountain in the middle and a bandstand near by, will slope down toward the river. As there are many fine trees along the shore it will be a cool and pleasant place to sit in summer. The stone bridge I am to put up will cross just above and serve as a sort of entrance to the park. We intend that everything shall be laid out with a view to making the river front attractive. As for the village itself--the streets are to be wide so that each dwelling shall have plenty of fresh air and sunshine. No more of those dingy flats such as the Turners live in! Each family is also to have land enough for a small garden, and each house will have a piazza and the best of plumbing; and because many of the women live in their kitchens more than in any other part of their abode, I am insisting that that room be as comfortable and airy as it can be made." "It is all bully, Grandfather," Laurie answered. "But isn't it going to cost a fortune to do the thing as you want it done?" "It is going to cost money," nodded the elder man. "I am not deceiving myself as to that. But I have the money and if I chose to spend it on this _fad_ (as one of my friends called it) I don't see why I shouldn't do it. Since your grandmother died I have not felt the same interest in Aldercliffe that I used to. When she was alive that was my hobby. I shall simply be putting out the money in a different direction, that is all. Perhaps it will be a less selfish direction, too." "It certainly is a bully fine fad, Grandfather," Laurie exclaimed. "Somehow I believe it is, laddie," the old gentleman answered thoughtfully. "Your father thinks so. Time only can tell whether I have chucked my fortune in a hole or really invested it wisely. I have been doing a good deal of serious thinking lately, thanks to those chaps who tried to blow up the mills. As I have turned matters over in my mind since the trial, and struggled to get their point of view, I have about come to the conclusion that they had a fair measure of right on their side. Not that I approve of their methods," continued he hastily, raising a protesting hand, when Laurie offered an angry interruption. "Do not misunderstand me. The means they took was cowardly and criminal and I do not for a moment uphold it. But the thing that led them to act as they planned to act was that they honestly believed we had not given them and their comrades a square deal. As I have pondered over this conviction of theirs, I am not so sure but they were right in that belief." He paused to light a fresh cigar which he silently puffed for a few moments. "This village plan of mine has grown to some extent out of the thinking to which this tragedy has stimulated me. There can be no question that our fortunes have come to us as a result of the hard labor of our employees. I know that. And I also know that we have rolled up a far larger proportion of the profits than they have. In fact, I am not sure we have not accepted a larger slice than was our due; and I am not surprised that some of them are also of that opinion. I would not go so far as to say we have been actually dishonest but I am afraid we have not been generous. The matter never came to me before in precisely this light and I confess frankly I am sorry that I have blundered. Nevertheless, as I tell your father, it is never too late to mend. If we have made mistakes we at least do not need to continue to make them. So I have resolved to pay up some of my past obligations by building this village and afterward your dad and I plan to raise the wages of the workers--raise them voluntarily without their asking. I figure we shall have enough to keep the wolf from the door, even then," he added, smiling, "and if we should find we had not why we should simply have to come back on you and Ted Turner to support us, that's all." Laurie broke into a ringing laugh. "I would much rather you and Dad spent the money this way than to have you leave it all to me," he said presently. "One person does not need so much money. It is more than his share of the world's profits--especially if he has earned none of it. Besides, when a fortune is handed over to you, it spoils all the fun of making one for yourself." The boy's eyes clouded wistfully. "I suppose anyhow I never shall be able to work as hard as you and Father have; still I----" "Pooh! Pooh! Nonsense!" his grandfather interrupted huskily. "I believe I shall be able to earn enough to take care of myself," continued Laurie steadily. "In any case I mean to try." "Of course you will!" cried the elder man heartily. "Why, aren't you expecting to be an engineer or something?" "I--I--hope--to," replied the boy. "Certainly! Certainly!" fidgeted Grandfather Fernald nervously. "You are going to be a great man some day, Laurie--a consulting engineer, maybe; or a famous electrician, or something of the sort." "I wish I might," the lad repeated. "You see, Grandfather, it is working out your own career that is the fun, making something all yourself. That is why I hate the idea of ever stepping into your shoes and having to manage the mills. All the interesting part is done already. You and Dad had the pleasure----" "The damned hard work, you mean," cut in his grandfather. "Well, the hard work, then," chuckled Laurie, "of building the business up." "That is true, my boy," replied Mr. Fernald. "It was a great game, too. Why, you know when I came here and we staked out the site for the mills, there wasn't a house in sight. There was nothing but that river. To one little wooden factory and that rushing torrent of water I pinned my faith. Every cent I possessed in the world was in the venture. I must make good or go under. Nobody will ever know how I slaved in those early days. For years I worked day and night, never giving myself time to realize that I was tired. But I was young and eager and although I got fagged sometimes a few hours of sleep sent me forth each morning with faith that I could slay whatever dragons I might encounter. As I look back on those years, hard though they were, they will always stand out as the happiest ones of my life. It was the fight that was the sport. Now I am an old man and I have won the thing I was after--success. Of course, it is a satisfaction to have done what you set out to do. But I tell you, laddie, that after your money is made, the zest of the game is gone. Your fortune rolls up then without you and all you have to do is to sit back and watch it grow of itself. It doesn't seem to be a part of you any more. You feel old, and unnecessary, and out of it. You are on the shelf." "That is why I want to begin at the beginning and earn my own money, Grandfather," Laurie put in. "Think what you would have missed if some one had deprived you of all your fun when you were young. You wouldn't have liked it." "You bet I wouldn't!" cried the old gentleman. "I don't want to lose my fun either," persisted Laurie. "I want to win my way just as you and Dad have done--just as Ted Turner is going to do. I want to find out what is in me and what I can do with it." Grandfather Fernald rubbed his hands. "Bully for you, Laurie! Bully for you!" he ejaculated. "That's the true Fernald spirit. It was that stuff that took me away from my father's farm in Vermont and started me out in the world with only six dollars in my pocket. I was bound I would try my muscle and I did. I got some pretty hard knocks, too, while I was doing it. Still, they were all in the day's work and I never have regretted them. But I didn't mean to have your father go through all I did and so I saw that he got an education and started different. He knew what he was fighting and was armed with the proper weapons instead of going blind into the scrimmage. That is what we are trying to do for you and what we mean to do for Ted Turner. We do not intend to take either of you out of the fray but we are going to put into your hands the things you need to win the battle. Then the making good will depend solely on you." "I mean to try to do my part." "I know you do, laddie; and you'll do it, too." "I just wish I was stronger--as well as Ted is," murmured the boy. "I wish you were," his grandfather responded gently, touching his grandson's shoulder affectionately with his strong hand. "If money could give you health you should have every farthing I possess. But there are things that money cannot do, Laurie. I used to think it was all-powerful and that if I had it there was nothing I could not make mine. But I realize now that many of the best gifts of life are beyond its reach. We grow wiser as we grow older," he concluded, with a sad shake of his head. "Sometimes I think we should have been granted two lives, one to experiment with and the other to live." He rose, a weary shadow clouding his eyes. "Well, to live and learn is all we can do; and thank goodness it is never too late to profit by our errors. I have learned many things from Ted Turner; I have learned some more from his father; and I have added to all these certain things that those unlucky wretches, Sullivan and Cronin, have demonstrated to me. Who knows but I may make Freeman's Falls a better place in consequence? We shall see." With these parting reflections the old gentleman slowly left the room. CHAPTER XVI ANOTHER CALAMITY The winter was a long and tedious one with much cold weather and ice. Great drifts leveled the fields about Aldercliffe and Pine Lea, shrouding the vast expanse of fields along the river in a glistening cloak of ermine spangled with gold. The stream itself was buried so deep beneath the snow that it was difficult not to believe it had disappeared altogether. Freeman's Falls had never known a more severe season and among the mill employees there was much illness and depression. Prices were high, business slack, and the work ran light. Nevertheless, the Fernalds refused to shorten the hours. There were no night shifts on duty, to be sure, but the hum of the machinery that ceased at twilight resumed its buzzing every morning and by its music gladdened many a home where anxiety might otherwise have reigned. That the factories were being operated at a loss rather than throw the men out of employment Ted Turner could not help knowing for since he had become a member of the Fernald household he had been included so intimately in the family circle that it was unavoidable he should be cognizant of much that went on there. As a result, an entirely new aspect of manufacture came before him. Up to this time he had seen but one side of the picture, that with which the working man was familiar. But now the capitalist's side was turned toward him and on confronting its many intricate phases he gained a very different conception of the mill-owner's conundrums. He learned now for the first time who it was that tided over business in its seasons of stress and advanced the money that kept bread in the mouths of the workers. He sensed, too, as he might never have done otherwise, who shouldered the burden of care not alone during working hours but outside of them; he glimpsed something of the struggles of competition; the problems of securing raw material; the work concerning credits. A very novel viewpoint it was to the boy, and as he regarded the complicated web, he found himself wondering how much of all this tangle was known to the men, and whether they were always fair to their employer. He had frequently overheard conversations at his father's when they had proclaimed how easy and care-free a life the rich led, and while they had envied and criticized and slandered the Fernalds and asserted that they did nothing but enjoy themselves, he had listened. Ah, how far from the truth this estimate had been! He speculated, as he reviewed the facts and vaguely rehearsed the capitalist's enigmas whether, if shown the actual conditions, the townsfolk would have been willing to exchange places with either of these men whose fortunes they so greedily coveted. For in very truth the Fernalds seemed to Ted persons to be pitied far more than envied. Stripped of illusions, what was Mr. Lawrence Fernald but an old man who had devoted himself to money-making until he had rolled up a fortune so large that its management left him no leisure to enjoy it? Eager to accumulate more and ever more wealth, he toiled and worried quite as hard as he would have done had he had no money at all; he often passed sleepless nights and could never be persuaded to take a day away from his office. He slaved harder than any of those he paid to work for him and he had none of their respite from care. Mr. Clarence Fernald, being of a younger generation, had perhaps learned greater wisdom. At any rate, he went away twice a year for extended pleasure trips. Possibly the fact that his father had degenerated into a mere money-making machine was ever before him, serving as a warning against a similar fate. However that may have been, he did break resolutely away from business at intervals, or tried to. Nevertheless, he never could contrive to be wholly free. Telegrams pursued him wherever he went; his secretary often went in search of him; and many a time, like a defeated runaway whose escape is cut short, he was compelled to abandon his holiday and return to the mills, there to straighten out some unlooked-for complication. Day and night the responsibilities of his position, the welfare of the hundreds of persons dependent on him, weighed down his shoulders. And even when he was at home in the bosom of his family, there was Laurie, his son, his idol, who could probably never be well! What man in all Freeman's Falls could have envied him if acquainted with all the conditions of his life? This and many another such reflection engrossed Ted, causing him to wonder whether there was not in the divine plan a certain element of equalization. In the meantime, his lessons with Laurie and Mr. Hazen went steadily and delightfully on. How much more could be accomplished with a tutor who devoted all his time simply to two pupils! And how much greater pleasure one derived from studying under these intimate circumstances! In every way the arrangement was ideal. Thus the winter passed with its balancing factors of work and play. The friendship between the two boys strengthened daily and in a similar proportion Ted's affection for the entire Fernald family increased. It was when the first thaw made its appearance late in March that trouble came. Laurie was stricken with measles, and because of the contagion, Ted's little shack near the river was hastily equipped for occupancy, and the lad was transferred there. "I can't have two boys sick," declared Mr. Clarence Fernald, "and as you have not been exposed to the disease there is no sense in our thrusting you into its midst. Plenty of wood will keep your fireplace blazing and as the weather is comparatively mild I fancy you can contrive to be comfortable. We will connect the telephone so you won't be lonely and so you can talk with Laurie every day. The doctor says he will soon be well again and after the house has been fumigated you can come back to Pine Lea." Accordingly, Ted was once more ensconced in the little hut and how good it seemed to be again in that familiar haunt only he realized. Before the first day was over, he felt as if he had never been away. Pine Lea might boast its conservatories, its sun parlors, its tiled baths, its luxuries of every sort; they all faded into nothingness beside the freedom and peace of the tiny shack at the river's margin. Meanwhile, with the gradual approach of spring, the sun mounted higher and the great snow drifts settled and began to disappear. Already the ice in the stream was breaking up and the turbid yellow waters went rushing along, carrying with them whirling blocks of snow. As the torrent swept past, it flooded the meadows and piled up against the dam opposite the factories great frozen, jagged masses of ice which ground and crashed against one another, so that the sounds could be distinctly heard within the mills. At some points these miniature icebergs blocked the falls and held the waters in check until, instead of cascading over the dam, they spread inland, inundating the shores. The float before Ted's door was covered and at night, when all was still and his windows open, he could hear the roaring of the stream, and the impact of the bumping ice as it sped along. Daily, as the snows on the far distant hillsides near the river's source melted, the flood increased and poured down in an ever rising tide its seething waters. Yet notwithstanding the fact that each day saw the stream higher, no one experienced any actual anxiety from the conditions, although everybody granted they were abnormal. Of course, there was more ice in the river than there had been for many years. Even Grandfather Fernald, who had lived in the vicinity for close on to half a century, could not recall ever having witnessed such a spring freshet; nor did he deny that the weight of ice and water against the dam must be tremendous. However, the structure was strong and there was no question of its ability to hold, even though this chaos of grinding ice-cakes boomed against it with defiant reverberation. In spite of the conditions, Ted felt no nervousness about remaining by himself in the shack and perhaps every premonition of evil might have escaped him had he not been awakened one morning very early by a ripple of lapping water that seemed near at hand. Sleepily he opened his eyes and looked about him. The floor of the hut was wet and through the crack beneath the door a thread of muddy water was steadily seeping. In an instant he was on his feet and as he stood looking about him in bewilderment he heard the roar of the river and detected in the sound a threatening intonation that had not been there on the previous day. He hurried to the window and stared out into the grayness of the dawn. The scene that confronted him chilled his blood. The river had risen unbelievably during the night. Not only were the little bushes along the shore entirely submerged but many of the pines standing upon higher ground were also under water. As he threw on his clothes, he tried to decide whether there was anything he ought to do. Would it be well to call up the Fernalds, or telephone to the mills, or to the village, and give warning of the conditions? It was barely four o'clock and the first streaks of light were but just appearing. Nevertheless, there must be persons who were awake and as alert as he to the transformation the darkness had wrought. Moreover, perhaps there was no actual danger, and should this prove to be the case, how absurd he would feel to arouse people at daybreak for a mere nothing. It was while he paused there indecisively that a sight met his eye which spurred hesitancy to immediate action. Around the bend far up the stream came sweeping a tangle of wreckage--trees, and brush, and floating timber--and swirling along in its wake was a small lean-to which he recognized as one that had stood on the bank of the river at Melton, the village located five miles above Freeman's Falls. If the water were high enough to carry away this building, it must indeed have risen to a menacing height and there was not a moment to be lost. He rushed to the telephone and called up Mr. Clarence Fernald who replied to his summons in irritable, half-dazed fashion. "Is there any way of lifting the water gates at the mills?" asked Ted breathlessly. "The river has risen so high that it is sweeping away trees and even some of the smaller houses from the Melton shore. If the debris piles up against the dam, the pressure may be more than the thing can stand. Besides, the water will spread and flood both Aldercliffe and Pine Lea. I thought I'd better tell you." Mr. Fernald was not dazed now; he was broad awake. "Where are you?" inquired he sharply. "At the shack, sir. The water is ankle deep." "Don't stay there another moment. It is not safe. At any instant the whole hut may be carried away. Gather your traps together and call Wharton or Stevens--or both of them--to come and help you take them up to Aldercliffe. I'll attend to notifying the mills. You've done us a good turn, my boy." During the next hour Ted himself was too busy to appreciate the hectic rush of events that he had set moving, or realize the feverish energy with which the Fernalds and their employees worked to avert a tragedy which, but for his warning, might have been a very terrible one. The mills were reached by wire and the sluices at the sides of the central dam immediately lifted to make way for the torrent of snow, ice, wreckage, and water. In what a fierce and maddened chaos it surged over the falls and dashed into the chasm beneath! All day the mighty current boiled and seethed, overflowing the outlying fields with its yellow flood. Nevertheless, the great brick factories that bordered the stream stood firm and so did the residences at Aldercliffe and Pine Lea, both of which were fortunately situated on high ground. Ted had not made his escape from his little camp a moment too soon, for while he stood looking out on the freshet from one of the attic windows at Pine Lea, he shivered to behold his little hut bob past him amid the rushing waters and drift into an eddy on the opposite shore along with a mass of uprooted pines. A sob burst from him. "It's gone, Mr. Hazen--our little house!" he murmured brokenly to the young tutor who was standing beside him. "We never shall see it again." "You mustn't take it so to heart, Ted," the teacher answered, laying his hand sympathetically on the lad's shoulder. "Suppose you had been in it and borne away to almost certain death. That would have been a calamity indeed. What is an empty boathouse when we consider how many people are to suffer actual financial loss and perhaps forfeit everything they have, as a result of this tragedy. The villagers who live along the river will lose practically everything they own--boats, poultry, barns; and many of them both houses and furniture. We all loved the shack; but it is not as if its destruction left you with no other roof above your head. You can stay at Aldercliffe, Pine Lea, or join your family at Freeman's Falls. Three shelters are open to you. But these poor souls in the town----" "I had not thought about the villagers," blushed Ted. "The Fernalds have been in the settlement since dawn and along with every man they could summon have been working to save life and property. If I had not had to stay here with Laurie, I should have gone to help, too." Ted hung his head. "I'm ashamed to have been so selfish," said he. "Instead of thinking only of myself, I ought to have been lending a hand to aid somebody else. It was rotten of me. Why can't I go down to the village now? There must be things I can do. Certainly I'm no use here." "No, there is nothing to be done here," the tutor agreed. "If you could stay with Laurie and calm him down there would be some sense in your remaining; but as it is, I don't see why you shouldn't go along to the town and fill in wherever you can. I fancy there will be plenty to do. The Fernalds, Wharton, Stevens, and the rest of the men are moving the families who lived along the water front out of their houses and into others. All our trucks and cars are busy at the job." "I know I could help," cried Ted eagerly, his foot on the top step of the staircase. "I am sure you can," Mr. Hazen replied. "Already by your timely warning you have helped more than you will ever know. I tremble to think what might have happened if you had not awakened Mr. Clarence just when you did. Had the dam at the mills gone down, the whole town would have been devastated. Mr. Fernald told me so himself." "I'm mighty glad if I----" "So you see you have been far from selfish," continued the tutor, in a cheery tone. "As for the shack, it can be rebuilt, so I should not mourn about that." "I guess Mr. Fernald is glad now that he has his plans ready for his model village." "Yes, he is. He said right away that it was providential. The snow will disappear after this thaw and as soon as the earth dries up enough to admit of building, the workmen will begin to break ground for the new settlement. The prospect of other and better houses than the old ones will encourage many of the mill people who have had their dwellings ruined to-day and in consequence been forced to move into temporary quarters where they are crowded and uncomfortable. We can all endure inconvenience when we know it is not to last indefinitely. Mr. Fernald told me over the telephone that the promise of new houses by summer or fall at the latest was buoying up the courage of all those who had suffered from this terrible disaster. He is going to grant special privileges to every family that has met with loss. They are to be given the first houses that are finished." "I do hope another freshet like this one won't sweep away the new village," reflected Ted. "Oh, we shall probably never again be treated to an excitement similar to this one," smiled Mr. Hazen reassuringly. "Didn't you hear them say that it was the bursting of the Melton reservoir which was largely responsible for this catastrophe? Mr. Fernald declared all along that this was no ordinary freshet. He has seen the river every spring for nearly forty years and watched it through all its annual thaws; and although it has often been high, it has never been a danger to the community. He told me over the telephone about the reservoir bursting. He had just got the news. It seems the reservoir above Melton was an old one which the authorities have realized for some time must be rebuilt. They let it go one year too long. With the weight of water, snow, and ice, it could not bear the pressure put upon it and collapsed. I'm afraid it has been a severe lesson to the officials of the place for the chance they took has caused terrible damage." "Were people killed?" asked Ted in an awed whisper. "We have heard so--two or three who were trapped asleep in their houses. As for the town, practically all the buildings that fronted the river were destroyed. Of course, as yet we have not been able to get very satisfactory details, for most of the wires were down and communication was pretty well cut off. I suppose that is why they did not notify us of our peril. People were probably too busy with their own affairs, too intent on saving their own lives and possessions to think of anything else. Then, too, the thing came suddenly. If there hadn't been somebody awake here, I don't know where we should have been. I don't see how you happened to be astir so early." "Nor I," returned Ted modestly. "I think it must have been the sound of the water coming in that woke me. I just happened to hear it." "Well, it was an almighty fortunate happen--that is all I can say," asserted Mr. Hazen, as the boy sped down the stairs. CHAPTER XVII SURPRISES During the next few days tidings of the Melton disaster proved the truth of Mr. Hazen's charitable suppositions, for it was definitely learned that the calamity which befell the village came entirely without warning, and as the main part of the town was wiped out almost completely and the river front destroyed, all communication between the unfortunate settlement and the outside world had been cut off so that to send warnings to the communities below had been impossible. Considering the enormity of the catastrophe, it was miraculous that there had not been greater loss of life and wider spread devastation. A week of demoralization all along the river followed the tragedy; but after the bulk of wreckage was cleared away and the stream had dropped to normal, the Fernalds actually began to congratulate themselves on the direful event. "Well, the thing has not been all to the bad, by any means," commented Grandfather Fernald. "We have at least got rid of those unsightly tenements bordering the water which were such a blot on Freeman's Falls; and once gone, I do not mean to allow them ever to be put back again. I have bought up the land and shall use it as the site of the new granite bridge I intend to build across the stream. And in case I have more land than is needed for this purpose, the extra area can be used for a park which will be an ornament to the spot rather than an eyesore. Therefore, take it altogether, I consider that freshet a capital thing." He glanced at Ted who chanced to be standing near by. "I suppose you, my lad, do not entirely agree with me," added he, a twinkle gleaming beneath his shaggy brows. "You are thinking of that playhouse of yours and Laurie's that was carried off by the deluge." "I am afraid I was, sir." "Pooh! Nonsense!" blustered the old gentleman. "What's a thing like that? Besides, Laurie's father proposes to rebuild it for you. Hasn't he told you?" questioned the man, noticing the surprise in the boy's face. "Oh, yes, indeed! He is going to put up another house for you; and judging from his plans, you will find yourself far better off than you were in the first place for this time he is to give you a real cottage, not simply a made-over boathouse. Yes, there is to be running water; a bedroom, study, and kitchenette; to say nothing of a bath and steam heat. He plans to connect it by piping with the central heating plant. So you see you will have a regular housekeeping bungalow instead of a camp." Ted gasped. "But--but--I can't let Mr. Fernald do all this for me," he protested. "It's--it's--too much." "I shouldn't worry about him, if I were you," smiled the elder man. "It won't scrimp him, I imagine. Furthermore, it will be an excellent investment, for should the time ever come when you did not need the house it could be rented to one of our tenants. He is to put a foundation under it this time and build it more solidly; and possibly he may decide to set it a trifle farther back from the water. In any case, he will see that it is right; you can trust him for that. It will not be carried away a second time." "I certainly hope not," Ted agreed. "What a pity it was they did not have some way of notifying us from Melton! If they had only had a wireless apparatus----" he broke off thoughtfully. "I doubt if all the wireless in the world could have saved your little hut," answered Mr. Fernald kindly. "It was nothing but a pasteboard house and wireless or no wireless it would have gone anyway. I often speculate as to how ships ever dared to go to sea before they had the protection of wireless communication. Ignorance was bliss, I suppose. They knew nothing about it and therefore did not miss it. When we can boast no better way we are satisfied with the old. But think of the shipwrecks and accidents that might have been averted! You will be studying about all this some day when you go to Technology or college." Ted's face lighted at the words. "You have all been so kind to me, Mr. Fernald," he murmured. "When I think of your sending me to college it almost bowls me over." "You must never look upon it as an obligation, my boy," the old gentleman declared. "If there is any obligation at all (and there is a very real one) it is ours. The only obligation you have will be to do well at your studies and make us proud of you, and that you are doing all the time. Mr. Hazen tells me you are showing splendid progress. I hope by another week Laurie will be out of the woods, Pine Lea will be fumigated, and you can resume your former way of living there without further interruptions from floods and illness. Still, I shall be sorry to have your little visit at Aldercliffe come to an end. You seem to have grown into the ways of the whole family and to fit in wherever you find yourself." Mr. Fernald smiled affectionately at the lad. "There is something that has been on my tongue's end to whisper to you for some time," he went on, after a brief interval of hesitancy. "I know you can keep a secret and so I mean to tell you one. In the spring we are going to take Laurie over to New York to see a very celebrated surgeon who is coming from Vienna to this country. We hear he has had great success with cases such as Laurie's and we hope he may be able to do something for the boy. Of course, no one knows this as yet, not even Laurie himself." "Oh, Mr. Fernald! Do you mean there would be a chance that Laurie could walk sometime?" Ted cried. The old man looked into the young and shining face and nervously brushed the back of his hand across his eyes. "Perhaps; perhaps!" responded he gruffly. "Who can tell? This doctor has certainly performed some marvelous cures. Who knows but the lad may some day not only walk about, but leap and run as you do!" "Oh, sir--!" "But we must not be too sure or allow ourselves to be swept away by hope," cautioned Grandfather Fernald. "No one knows what can be done yet and we might be disappointed--sadly disappointed. Still, there is no denying that there is a fighting chance. But keep this to yourself, Ted. I must trust you to do that. If Laurie were to know anything about it, it would be very unfortunate, for the ordeal will mean both pain and suffering for him and he must not be worried about it in advance. He will need all his nerve and courage when the time for action comes. Moreover, we feel it would be cruel for him to glimpse such a vision and then find it only a mirage. So we have told him nothing. But I have told you because you are fond of him and I wanted you to share the secret." "It shall remain a secret, Mr. Fernald." "I feel sure of that," the man replied. "You are a good boy, Ted. It was a lucky day that brought you to Pine Lea." "A lucky one for me, sir!" "For all of us, son! For all of us!" reiterated the old gentleman. "The year of your coming here will be one we never shall forget. It has been very eventful." Certainly the final comment was no idle one. Not only had the year been a red-letter one but it was destined to prove even more conspicuously memorable. With the spring the plans for the new village went rapidly forward and soon pretty little concrete houses with roofs of scarlet and trimmings of green dotted the slopes on the opposite side of the river. The laying out and building of this community became Grandfather Fernald's recreation and delight. Morning, noon, and evening he could be seen either perusing curling sheets of blue prints, consorting with his architects, or rolling off in his car to inspect the progress of the venture. Sometimes he took Ted with him, sometimes his son, and when Laurie was strong enough, the entire family frequently made the pilgrimage to the new settlement. It was very attractive, there was no denying that; and it seemed as if nothing that could give pleasure to its future residents had been omitted. The tiny library had been Laurie's pet scheme, and not only had his grandfather eagerly carried out the boy's own plans but he had proudly ordered the lad's name to be chiselled across the front of the building. Ted's plea had been for a playground and this request had also been granted, since it appeared to be a wise one. It was a wonderful playground, bordering on the river and having swings and sand boxes for the children; seats for tired mothers; and a large ball-field with bleachers for the men and boys. The inhabitants of Freeman's Falls had never dreamed of such an ideal realm in which to live, and as tidings of the paradise went forth, strangers began to flock into town in the hope of securing work in the mills and homes in the new settlement. The Fernalds, however, soon made it plain that the preference was to be given to their old employees who had served them well and faithfully for so many years. Therefore, as fast as the houses were completed, they were assigned to those who had been longest in the company's employ and soon the streets of the new village were no longer silent but teemed with life and the laughter of a happy people. And among those for whom a charming little abode was reserved were the Turners, Ted's family. Then came the tearing down of the temporary bridge of wood and the opening of the beautiful stone structure that arched the stream. Ah, what a holiday that was! The mills were closed, there was a band concert in the little park, dedication exercises, and fireworks in the evening. And great was Ted's surprise when he spied cut in the stone the words "Turner's Bridge!" Near the entrance was a modest bronze tablet stating that the memorial had been constructed in honor of Theodore Turner who, by his forethought in giving warning of the freshet of 1912 had saved the village of Freeman's Falls from inestimable calamity. How the boy blushed when Mr. Lawrence Fernald mentioned him by name in the dedication speech! And yet he was pleased, too. And how the people cheered; and how proud his father and sisters were! Perhaps, however, the most delighted person of all was Laurie who had been in the secret all along and who now smiled radiantly to see his friend so honored. "The townspeople may not go to my library," he laughed, "but every one of them will use your bridge. They will have to; they can't help it!" The thought seemed to amuse him vastly and he always referred to the exquisite granite structure with its triple arch and richly carved piers of stone as _Ted's Bridge_. Thus did the year with its varied experiences slip by and when June came the Fernalds carried Laurie to New York to consult the much heralded Viennese surgeon. Ah, those were feverish, anxious days, not only for the Fernald family but for Ted and Mr. Hazen as well. The boy and the tutor had remained at Pine Lea there to continue their studies and await the tidings Laurie's father had promised to send them; and when the ominous yellow telegrams with their momentous messages began to arrive, they hardly knew whether to greet them with sorrow or rejoicing. They need not, however, have dreaded the news for after careful examination the eminent specialist had decided to take a single desperate chance and operate with the hope of success. Laurie, they were told, was a monument of courage and had the spirit of a Spartan. Unquestionably he merited the good luck that followed for fortune did reward his heroism,--smiling fortune. Of course, the miracle of health could not come all in a moment; months of convalescence must follow which would be unavoidably tedious with suffering. But beyond this arid stretch of pain lay the goal of recovery. No lips could tell what this knowledge meant to those who loved the boy. In time he was to be as strong as any one! It was unbelievable. Nevertheless, the roseate promise was no dream. Laurie was brought home to Pine Lea and immediately the mending process began. Already one could read in the patient face the transformation hope had wrought. There was some day to be college, not alone for Ted but for Laurie himself,--college, and sports, and a career. In the fullness of time these long-anticipated joys began to arrive. Health made its appearance and at its heels trouped success and happiness; and to balance them came gratitude, humility, and service. In the meantime, with every lengthening year, the friendship between Laurie and Ted toughened in fiber and became a closer bond. And it was not engineering or electricity that ultimately claimed the constructive interest of the two comrades but instead the Fernald mills, which upon Grandfather Fernald's retirement called for younger men at their helm. So after going forth into the great world and whetting the weapons of their intellect they found the dragon they had planned to slay waiting for them at home in Freeman's Falls. Yet notwithstanding its familiar environment, it was a very real dragon and resolutely the two young men attacked it, putting into their management of the extensive industry all the spirit of brotherhood that burned in their hearts and all the desire for service which they cherished. With the aim of bringing about a kindlier coöperation and fuller sympathy between capital and labor they toiled, and the world to which they gave their efforts was the better for it. Nevertheless, they did not entirely abandon their scientific interests for on the border of the river stood a tiny shack equipped with a powerful wireless apparatus. Here on a leisure afternoon Ted Turner and his comrade could often be found capturing from the atmosphere those magic sounds that spelled the intercourse of peoples, and the thought of nations; and often they spoke of Alexander Graham Bell and those patient pioneers who, together with him, had made it possible for the speech of man to traverse continents and circle a universe. FINIS 
32672	----	Transcriber's Note: This etext was produced from Amazing Stories January 1943. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed. DIRECT WIRE by CLEE GARSON Mort and Mike got strange calls on this phone; they didn't come through Central! * * * * * [Illustration: He had a strange husky voice that made queer chills go up and down your spine] There is an empty cigar store on the first floor of the loop building in which I keep my office. Formerly it was managed by two of the slickest small time gambling operators who ever booked a bang-tail or banked a game of Hooligan. There is a small, neatly lettered sign on the door of that unoccupied store now, however, which has caused no end of comment from the former customers of the "cigar store" who had always been all too cheerfully happy to lose their daily dollars there. The sign reads: "CLOSED FOR THE DURATION Due to our having Entered The Armed Forces of the U. S. GOD BLESS AMERICA Mort & Mike" If you haven't guessed as much by now, the signatures at the bottom of that sign are those of the two former proprietors of the establishment, Mort Robbins and Mike Harrigan. Now since both Mort and Mike were of military age, and since this nation is at war, it should hardly seem unusual that their former customers and all who knew them would consider their summons to the colors something worthy of great comment. It should hardly seem unusual, that is, unless you happened to know the two, and realized further that they were not drafted, but _voluntarily_ enlisted. Neither was what you could call deeply patriotic, you see. Nor were they the sort to be influenced by such emotional appeals as the beating of drums, the waving of flags, or the playing of brass bands marching along Jackson Boulevard. "We gotta lick them lice!" Mike constantly proclaimed in regard to Adolf and the Axis, when war discussions came up around the "cigar store." But aside from those loud and perhaps sincere pronouncements, Mike's only contribution to the cause of Victory was the purchase of war bonds which he looked on merely with the cold eye of one seeking a smart investment. And as for his attitude toward the army, Mike best expressed himself with a small embryo ulcer which he kept always on the verge of eruption within twenty-four hours notice to report for a draft board examination. It was rumored that, through a swift, sufficient amount of whisky, Mike could make his embryo ulcer dance angrily for the draft medicos at any time. This none too admirable accomplishment with an ailment not actually serious had kept Mike Harrigan in Class 4 F ever since the last draft registration. As for Mike's partner, Mort Robbins, the patriotic picture was pretty much the same. Mort was loudly belligerent toward our enemies in all the "cigar store" discussions, wisely put much of his funds into war bonds, but kept one of the most extensive libraries of medical statements from doctors in existence. All these statements concerned the tragic asthma and hay-fever of one Mort Robbins and went on to declare that he might possibly stop breathing completely should he be placed in the army. The fact that Mort had connived to get these statements and was not really seriously troubled by those two maladies didn't alter the fact that they had resulted so far in keeping him out of khaki. Consequently, since more than one of their customers knew or suspected their lack of practical patriotism, the appearance of that sign on the door of what had once been their establishment caused quite a considerable flurry of comment for a time. Naturally, no one could understand what had caused it all. For that, they can't be blamed. I'd never have understood it, if I hadn't accidentally been the one person in the world, outside of Mort and Mike, who knew the true story.... * * * * * On the morning that it all began, I was down in the "cigar store," killing time and having a coke and some conversation before going upstairs to the grimly reproachful surroundings of my too neglected office. Mike Harrigan was the only one behind the counter, and I was the only one on the customer side. Mike was red headed and freckle necked, a massive chap with a blarney smile and a baby face. He's been in the "cigar store" bookie racket ever since repeal had closed a speakeasy he'd had on Grand Avenue. This morning, however, he was glaring glumly down at a newspaper spread before him atop the glass cigar counter, and scarcely nodded to half my conversational sallies. "What's eating you, Mike?" I finally demanded. "That ulcer getting well in spite of you?" Mike ignored the crack. But he looked up from his reading and jabbed a big red freckled thumb down on a column of print in the paper before him. "That State's Attorney!" Mike snorted indignantly. "He's gonna go too far pretty damn soon!" "What now?" I grinned. Mike was always indignant over the efforts of the State's Attorney to "ruin an honest man's business" with his crack-downs on small-time handbooks throughout the city. "What's his latest move in the battle against Mike Harrigan?" "This here story in the paper," Mike declared, "says how the State's Attorney's office is starting to investigate the lists of the telephone company in order to track down any phones used by us bookmakers in our business. It's illegal!" He concluded with the virtuous snort of an indignant taxpayer shocked by the violation of law, smacking his big red-knuckled hand on the counter top to emphasize his disturbance. "Aha!" I said. "In other words the State's Attorney's office is going to find their way into this handbook of yours by the direct approach, eh? It'll take time for them, won't it, to go over the entire telephone lists?" "You never can tell," Mike predicted gloomily. "They might nail us all," he snapped his big fingers, "like that." I glanced over at the telephone booth in the corner of the store. Its folding door was open, and the ever-present "Out Of Order" sign was suspended from a cord around the mouthpiece. Over that phone Mike and Mort conducted the bulk of their horse booking business. Through it they kept in touch with a central gambling syndicate service which provided day-long racing results, odds and other essential data to numerous other such small establishments around the city. Through it, also, they took in a nice business of telephone bets from wagerers too busy to get in to make them in person. The never-missing "Out of Order" sign was to prevent customers from using the telephone for out-going calls which might interfere with business. The telephone was, of course, not at all out of order. "Maybe," I suggested cheerfully, taking my eyes from the telephone booth, "they'll snatch out your phone on you. Then where'll you be?" Mike smacked his open palm against his broad brow. "My God," he exclaimed, "don't say no such things!" I gulped the rest of my coke, lit another cigarette, shrugged cheerfully, and started for the door. I turned before leaving. "Cheer up," I said. "This will probably blow over. And if it doesn't, there's always the army." * * * * * Mike glared and started to answer. And at that moment the telephone in the booth began to ring. He started for it, and I started out the door again, running headlong into Mort Robbins. "Good morning, good morning, chumly!" Mort exclaimed cheerfully when we had untangled ourselves. "What's new with you?" Mort is short, slightly on the plump side, with straight, dark hair, a round, beaming face, and a penchant for flamboyantly colored sport shirts. "Nothing's new with me," I told him, "but plenty seems to be new with Mike. He's cursing the State's Attorney's office again." Mort frowned. "Whatcha mean? What's on the fire now? I didn't read the morning rags yet." Briefly, I told him about the news story which had excited his partner. He nodded, thought a moment, then grinned. "They can't do that," he said. "It's illegal." "Tell Mike, if that's so," I said. "He's working himself into a boil." Mort hadn't heard me. He was frowning thoughtfully again. "Or can they?" he wondered aloud. "Where's that news story?" I pointed to the paper on the counter and he stepped over to it. I started to leave again, but at that moment the telephone booth in the corner shook from side to side and Mike stepped out, face red with wrath. "I'd like to get my hands on that guy, the wisenheimer!" he growled. "Hah! Practical jokes, eh?" Again I stopped at the door. "What's wrong this time?" I demanded. "Or is it still the State's Attorney you're frothing about?" "Some guy," Mike thundered explosively, "just called to say he wanted to talk to Hitler and Mussolini. Wise guy, hah, the louse!" "Hitler and Mussolini?" I demanded. "Who was it?" "Wouldn't I like to know," Mike exclaimed redly. "Wouldn't I just like to know!" He made a grasping gesture with his two big fists, indicating what he would do to the party if he did know. Mort had put down the newspaper and had been listening to Mike's explosion. "Don't bust your buttons, Mike," Mort advised. "It's probably just one of our customers having a gag." "Bum gag, I say. If they wanta gag whyn't they gag funny?" Mike snorted angrily. "Talk to Hitler and Mussolini, eh? Huh!" And at that juncture, the telephone rang again. Mort looked up, then looked at me and winked. He turned to Mike, who'd started wrathfully for the booth. "Hold it, chumly," Mort said. "I'll answer this one. If it's the joker again I can handle him better than you can." * * * * * Mort walked nonchalantly over to the booth, took down the receiver, and turned to wink again at me. "Hello," Mort said. Obviously the voice on the other end of the wire said something. Mort grinned. "They ain't here," Mort said, grinning more widely. "No. Not either of 'em. Adolf sleeps late and don't get down until noon. Benito is out having himself a milkshake. Who'll I tell 'em called? Huh? What's that? You call back? But who'll I tell 'em called? Huh? Gab--Gabby? What?" Mort put the receiver back on the hook and turned back to us, stepping out of the booth. "The joker said to tell Adolf and Benito he'd call back later. I didn't get his name, but it sounded like Gabby. Smart joe, this Gabby." Mike was glaring. "Gabby, eh? Gabby, Gabby, Gabby," he scratched his red head frowningly. "Who do I know named Gabby?" "Skip it," Mort advised smilingly. "It wouldn't be the right monicker, anyway." Mike muttered dourly, moving back behind the counter. Suddenly he stopped. "You see the morning paper?" he asked his partner in sudden recollection. "You see about that louse State's Att--" "Yeah, I read it," Mort cut him off. "It'll blow over, even if they get away with it. But they might not even get away with it. It's illegal." Mike beamed for the first time since I'd seen him that morning. Obviously he was pleased to have his own legal judgment upheld by his partner. "You think so? That's what I thought." He turned to me. "Isn't that what I thought?" he demanded. "Did you call for the morning line check on the tracks yet?" Mort asked, changing the subject. Mike shook his head. "I was waiting for a few phone bets to come in, first," he said. "How many come in so far?" Mort asked. Mike suddenly looked at his wrist watch and swore. "None!" he exclaimed. "None and it's already after ten!" Mort looked alarmed. "You mean the phone ain't rang with a bet since you been down?" "Only time the phone rung was with that practical joker, twicet. You heard 'em," Mike declared. "But by this time we generally have a couple dozen bets in from the phones!" Mort exclaimed. "This is bad. Whatcha think goes?" "Goes?" Mike exclaimed indignantly. "How should I know what goes?" Mort suddenly clapped his palm to his brow. "Maybe it's got somethin' to do with that news story!" "About the State's Attorney gonna check the phone lists?" Mike demanded. "Yeah." Mike thought this over. "No," he decided. "Couldn't be. Not so soon, yet. Tomorrow, maybe, but not so soon." Mort calmed down a little. "You're right there," he said. "It wouldn't be so soon." "Maybe this is a bad day," I broke in. "Maybe your customers just aren't betting this morning." Mort and Mike looked at me as if I were crazy, which possibly I was. Two dozen steady horse players don't all stop at once, if ever. Mike was as sorely troubled as Mort. "We got at least couple dozen bets acrosst the counter already this morning," he said. "But no phone bets." "Maybe the damn thing is _actually_ out of order," Mort groaned, glancing at the telephone. "Then how did we get them two calls from the joker?" Mike demanded. "No. That phone ain't no more outta order than I am." "You're right. I forgot those calls," Mort acknowledged. * * * * * And at that moment the telephone rang again. Mort looked at Mike. Mike looked at Mort. Both wet their lips. "Ordinary days that joker might be funny," Mort said. "But now I'm thinking this isn't an ordinary day. I'm thinking it's not as funny as I first thought." He crossed to the telephone booth, jerked the receiver from the hook, and bellowed into the mouthpiece. "Hello!" There was a brief pause in which someone said something to him from the other end of the wire. "Listen!" Mort suddenly exploded. "Nothing is funny three times, wise guy. I wish you would take your Hitler-Mussolini gag and--" at which point he described what he wanted the caller to do with the gag. Then, slamming the receiver back into the hook, Mort stormed out of the booth. "Same guy?" Mike demanded, his veins bulging in his thick, freckled neck. "Same guy," Mort said grimly. His lips were tight. "He asked if we could get Hitler and Musso to the phone in a hurry. He said the connection was getting weaker and weaker, and he was afraid it wouldn't hold out much longer." "The connection?" I broke in, puzzled. Mort looked on the verge of apoplexy. "The connection from where he was calling to earth, the wise guy said!" he exploded. "If we could only trace that call I'd break that no-good's neck!" Mike and Mort evidently took turns acting as sobering influence on each other. "Now we don't wanta get too riled," Mike pointed out with surprising sense. "The gag artist prob'ly wants we should get mad like this. We'll forget 'em. I'll call for the morning line and the odd changes for the first races." Mort drummed his fingers on the cigar showcase, cooling himself off. Mike marched over to the telephone booth and wedged himself inside. With one big red finger, he dialed a number rapidly after he took the telephone from the hook. But he only half completed his dialing. It broke off as he uttered a choking curse. "Listen you!" Mike suddenly bellowed, the echoes in the booth almost knocking it over. "Get the hell offa this line! Howdja get on in the first place?" Mort stopped drumming his fingers and glanced startledly at the booth. Crimson began to return to his face. "What's up?" he shouted. He started toward the booth. I followed him. We could hear Mike spluttering incoherently inside. Then there was an ear-splitting racket as the big bookie smashed the receiver back into the hook and turned purple faced toward us. "The gag artist!" he raged. "The same damn wise guy. The Hitler-Mussolini smart aleck. He was waitin' on the line. He hadn't hung up. He told me he hadda wait on the line, cause he didn't dare break off the connection. He said it was too hard to make inna first place. He said he hoped we didn't mind if he waited until we got Adolf and Benito on the wire fer him!" * * * * * By now Mort was spluttering, and this time neither partner seemed to have a calming effect on the other. They were both raging, boiling mad. "I'll call the cops!" Mike bellowed. "That's what I'll do!" He began to pace up and down. "I'll have that guy electrocuted!" "I'm going out," Mort stormed, "and get the operator onna 'nother phone. I'll report that so-and-so, and they'll trace him down through the telephone company!" He started for the door. Mike grabbed his arm. "Waita minute!" he exclaimed. "We can't do that!" Mort tore his arm from his partner's grasp. "What's stopping us?" he demanded. "The State's Attorney's office!" Mike groaned. "Maybe it's a trap set by them skunks from the State's Attorney's office. Maybe it's the start of their telephone tracing of bookmakers!" Sickly, Mort turned back. His face was still flushed, but three fourths of his steam was gone. "Maybe you're right," he admitted. "And if so, what a helluva note this is!" I couldn't hold back my curiosity any longer. "Look," I said. "I have an idea. If it's a joker, perhaps I can talk him out of it better than you boys. You'll need that wire today, and the joker might just be drunk and obstinate enough to hang on all day long to spite you. Maybe he knows you won't dare report it. I'm not steamed up; maybe I'll reason with him better because I'm not. You want me to?" Mort and Mike gave me grateful glances. "You get ridda that wise guy," Mike said, "and we'll never ferget it!" "Go to it, chumly," Mort said, "and if you lose that louse, we'll make it up to you!" I went over to the booth and, stepping inside, took the receiver from the hook. I had a jovial, let's-be-friends opener all ready. "Hello, pal," I said amiably. The voice that came to my ears was distinctly unlike what I'd expected. I don't quite know _how_ or _why_ it sounded so strange and eerie, but it did. It was a man's voice, coming over the wire the way long distance calls used to sound before they got transmission technique down pat. "Hello there," said the voice. "Have they arrived yet?" It wasn't the voice of a drunk. And if it were that of a practical joker, the poker-faced quality of it was perfect acting. It sounded earnestly, eagerly serious. "You mean Adolf and Benito?" I asked. I was willing to play ball for a few minutes if it brought results. Besides, I was curious. "Yes." "Why do you want to talk to them?" I asked. "_I_ don't want to talk to them. My boss does," the voice answered. "Then put your boss on," I said. "I'll talk to him." "You are neither Hitler nor Mussolini," the voice replied. "He wishes to speak only to them. He's very busy. Too busy to waste time in idle conversation. Please fetch Hitler and Mussolini to the wire." "Who are you?" I demanded. "I have already covered that ground with the other parties I spoke to before you," the voice said. "Please hurry and bring Adolf and Benito to the phone. This connection is getting progressively worse. It can't last much longer. We spent several years getting it through, you know." "Did you now?" I asked politely. "Yes we did," the voice answered stiffly. Then, annoyed: "_Must_ you waste this precious time? Please bring Hitler and Mussolini to the telephone as quickly as possible." * * * * * There was a fuzzy crackling over the wire. Like a ship-to-shore connection. "Listen, pal," I said. "This joke is costing a couple of guys some lucrative trade. You are tying up a telephone they need badly in their business, or didn't you know that?" "That can't be helped," the voice said stiffly. "Be a good sport and get off the wire," I said. "I have no intention of doing that until my boss has talked to Hitler and Mussolini," the voice said coldly. I knew a positive statement when I heard one. I hung up, clambered out of the booth, spread my hands expressively to Mike and Mort who stood there eagerly waiting for some good word. "No soap," I said. "I don't think you got a joker on there, and I'd swear you haven't got a drunk." "What have we got, then," Mike demanded. "A smart copper waiting to trap us?" I shook my head. "I think you got a loony," I said. "But don't quote me." I started toward the door. "I got work to do, gents, but I'll look in again a little later. Hope you get rid of your pest." "We'd better," Mike moaned dismally. "Brother," Mort declared, pulling his hair and making a sincerely distraught face, "you're not kidding!" I looked at the telephone booth and shook my head. "Somebody is," I told them.... * * * * * For perhaps three hours I was able to concentrate on my work, with the telephone booth distraction cropping up only about every fifteen minutes or so to give me the fidgets. At the end of that time, a little before two o'clock, I finally covered up my reproachful typewriter and, on the excuse that I wanted a coke, left the office to go down and see how the boys were doing with the determined loony on their telephone. The "cigar store" was crowded with the usual early-afternoon hang-arounders when I walked in. Mort and Mike, each behind a dice board, were accommodating trusting suckers who had somehow gotten the mistaken idea that Hooligan was a game you beat every other time. Mike, looking up, noticed my entrance first. He signaled to me, muttered an excuse to the dice roller at his board, and came quickly around the counter. He took me by the arm and steered me out into the building lobby. "Listen, pal," he half-whispered, "fer gawdsakes don't say anything about the jerk on the telephone. Mort and me ain't told anyone, fer fear of the ribbing we'd get, plus the kick in the pants it would give our regular betting business over the counter." "You mean the guy's still on the telephone?" I demanded. Mike nodded a little sickly. "We can't get him off. And since we ain't letting on to no one about the phone being fritzed that way, every time he rings, we pretend we're getting an odd change, or some scratches or result. Mort an' me have been running our legs off, using a telephone next door to get our prices and results and such dope from the syndicate. But don't let on. We ain't told no one!" "Okay," I promised. "I'll keep mum. But who in the hell do you suppose it is?" Mike lowered his voice even more, looking furtively around the building lobby. "Confidentially, although we don't dare draw attention to our joint since the State's Attorney is telephone prowling, Mort and me decided you was right. It must be a loony. All we can do is wait until he gets tired and gets off." I nodded. "That's about all you can do," I agreed. "Does he still want to talk to Hitler and Mussolini?" Mike nodded disgustedly. "Worse than ever. Calling every twenty minutes now. Mort and me is going crazy answering them calls and pretending they ain't nothing but syndicate results." "I don't blame you," I said. "I would, too." Mike went back into the store and behind the dice board. I took a coke out of the cooler and uncapped it on the side of the machine. Mort sent me a message in his glance, and I nodded reassuringly to him. "I don't know anything," I said. Mort grinned a sick, grateful sort of grin, and went back to the task of taking quarters from his customers. Taking my time with my cigarette, I finished my coke. Then the telephone rang, as I'd been waiting for it to do. Mort dashed to the booth, closed the door as he entered, and for several flushed minutes appeared to be talking into the phone and writing something on a scratch pad. But I knew it was an act from the pained expression on his face. I knew that the loony was babbling away again and that Mort was having to listen for the sake of the pose. When at last he hung up, he emerged mopping his face with a gaily colored handkerchief. The look he shot me was confirmation enough that the loony was still on the wire. * * * * * Unable to feel too sorry for the boys, I concealed a grin behind a yawn, nodded to them both, and left the place. Upstairs once more in my office I got back into a rather muggy stream of work on which I found difficulty concentrating. For some reason I couldn't at first explain to myself, I kept thinking about the telephone loony of Mike and Mort's. Not because of the ironically ridiculous turmoil it threw them into, but for some other reason far more subtle, but which I was unable to put my finger on. The thing amused me, puzzled me, and yet, somehow was beginning to trouble me. Not through any great sympathy for Mike or Mort, of course. It will be a cold day when my heart bleeds for bookmakers. But something or other _was_ growing more and more bothersome. I thought about it a while, then shoved it out of my mind and got back to work. I was able to grind along for a couple of hours without having it come back into my mind. And when it popped up again, I shoved it away once more just as quickly. I had to get that work out, and I knew I wouldn't if I stewed any longer over the telephone loony who was quite probably still playing hob with Mike and Mort at that moment. It was a little after five o'clock, five-fifteen, to be exact, when--work or no work--the thing hit me. Bang! Like that I knew what'd been in the back of my mind. How in the name of blazes had the telephone loony been able to stay on that wire so indefinitely? Why hadn't the operator broken in to end the connection each time Mort or Mike hung up? It seemed logical that she would have done so. The loony couldn't have just held onto the telephone and been right on tap the moment Mort or Mike picked up the hook. The loony could have called them, of course, but it would have been impossible for him to be on hand every time they picked up the telephone when it hadn't been ringing! I left my typewriter, not even bothering to remove the page in it, and hurried out of the office. Downstairs I found the "cigar store" completely deserted except for Mike and Mort. The day's races were over, and dice customers who were willing enough to roll cubes in office time, had headed homeward. "Brother," Mort greeted me, "you were right and how!" "About the loony--" I began. "That's right," Mort said. "He was as loony a loony as I've ever heard of. We finally got rid of him." "Got rid of him?" I blurted the question. "Yeah," Mort nodded. "And I hope for good. He just faded off, about half an hour after his voice began to get dimmer and dimmer, and that was that." "But--" I began. "And wait'll you hear who that bug thought he was." "Gabby who?" I asked. "Gabby, nuts. I messed it up the first time. He thought he was Gabriel, the _Angel_ Gabriel, no less!" Mort exclaimed, tapping the side of his head. "The Angel Gabriel?" I echoed. Mort nodded. "And guess who he was calling for?" "Don't tell me," I said. "That's right," Mort declared. "He said he was God's secretary, Gabriel, calling from Heaven for his boss. He said his boss wanted to talk to Hitler and Mussolini!" * * * * * I blinked. "And what was God going to tell those lice?" "To take it on the lam, or else!" Mike broke in. "No fooling?" "So help me!" Mort swore. "What a loony. He went on to say--this fake Angel Gabriel--that his boss just wanted to tell those two jerks, Adolf and Benito, that enough was enough and they were dead ducks for sure." "What made this Gabriel from the nut house get so confidential all of a sudden?" I demanded. "He wouldn't tell his business at all at first." "This'll kill you," Mort said. "The connection, like I say, kept getting fainter and fainter, and our goofy Gabriel said it was fading off and that we'd have to hand the message on to Hitler and Mussolini for his boss, if we couldn't bring the two jerks to the phone to hear it in person." "Did he bother to explain," I asked, "why he didn't call Adolf and Benito directly, if his boss wanted to tell them off?" "So help me," Mort declared, "he did. He said that with the war all over our globe like it is, there was a lot of space interference everywhere preventin' communication. He said he couldn't be choosy, and had to use any wire he could get through to. It happened to be ours. Can you beat it?" I shook my head slowly. "No," I said, "I can't. But what trick could he have used to stay on the phone indefinitely, connected right to your wire, even after you hung up on him each time?" And then, briefly, I explained the rest of my puzzle over that little item. "If you can figure that out," I concluded, "we'll have to admit that, loony or not, he was nothing less than a mad genius." Mort shrugged. "I'm no telephone man," he said, "but there must be some explana--" His sentence stopped abruptly, and he and Mike seemed to be looking over my shoulder. I turned, to see an overall clad chap carrying a canvas toolbag just stepping through the door. He smiled cheerfully at the three of us. "I'm the man from the telephone company," he said amiably. "I got here a little earlier today, missed you last night. Had to have the night elevator operator let me into your store. Hope you weren't too inconvenienced today." "What's it all about?" Mort demanded. "What do you mean? You know about the loony?" The telephone man had stopped by the booth. He was opening his tool bag. He looked up. "Loony? No, I'm sorry, I don't know anything about any loony." "Who called himself the Angel Gabriel?" Mike broke in. The telephone man smiled up at us in genial bewilderment. "I'm sorry, gentlemen," he said, "I don't quite get the drift of all this. All I know is that I was in here last night to disconnect your telephone temporarily, and I'm back again tonight to return it to service. I saw your "Out of Order" sign there, so I thought you'd expected me and knew all about it." * * * * * Mort stepped forward. His face a curious picture of bewilderment and disbelief, he asked: "Wait a minute! You mean to say this telephone hasn't been connected all day today?" The telephone man nodded. "That's right. But I'm putting it back in order now." "We got calls over that phone today!" Mike asserted vigorously. "It couldn't have been disconnected." The telephone man chuckled. "Good joke. You couldn't have received a call over this telephone. It would have been utterly impossible. It was completely disconnected." He went on tool sorting. Mike was looking at Mort. Mort was looking at the telephone man. I was looking at all three, and the telephone man was unconcernedly taking out wires from his bag. "You--you aren't kidding?" Mort's voice came choked. "This was really disconnected?" The telephone man shoved the booth a little to one side, grabbed some wires then visible beneath the booth, and pulled them forth. They were all neatly severed, with the ends taped. Mike and Mort were staring at the severed ends of the wires, then at one another. "Mike," said Mort, "I think it is a good idea we should get drunk." "My old lady," said Mike, "used to believe in this sort of stuff. Maybe she wasn't such a dope." Mort nodded. "My old man, too." Neither said a word to me. Neither spoke to the telephone man. They just walked out, arm in arm, never looking back once, even at the cash register. I understand they got drunk that night. But I understand Mike kept his ulcer carefully under the explosive line, so that he passed the enlistment exams the following morning. Mort left his medical statements home, and of course a direct exam showed him nicely suited for the army. They were inducted by noon that day, and on their way to camp by dinner time. They left that sign on the door. The sign that puzzled so very many people, even to the "God Bless America" on it. For Mike and Mort were as little known for their religious leanings as they'd been for their patriotic urgings. Relatives of the two, I am told, disposed of the store's stock and equipment. Mort didn't discuss any of that in the short note he left for me before leaving with Mike. "Dear Chum: Of course when you get a message like we got, and are told to pass it along personally to the two jerks it was intended for, there's nothing else you can do. We'll see that it gets to Adolf and Benito--for Gabriel's boss. Mort & Mike." * * * * * 
12375	----	[Illustration: SAMUEL FINLEY BREESE MORSE Inventor of the Telegraph] MASTERS OF SPACE MORSE _and the Telegraph_ THOMPSON _and the Cable_ BELL _and the Telephone_ MARCONI _and the Wireless Telegraph_ CARTY _and the Wireless Telephone_ BY WALTER KELLOGG TOWERS ILLUSTRATED 1917 TO MY CO-LABORER AND COMPANION BERENICE LAURA TOWERS WHOSE ENCOURAGEMENT AND ASSISTANCE WERE CONSTANT IN THE GATHERING AND PREPARATION OF MATERIAL FOR THIS VOLUME. CONTENTS CHAP. PREFACE I. COMMUNICATION AMONG THE ANCIENTS II. SIGNALS PAST AND PRESENT III. FORERUNNERS OF THE TELEGRAPH IV. INVENTIONS OF SIR CHARLES WHEATSTONE V. THE ACHIEVEMENT OF MORSE VI. "WHAT HATH GOD WROUGHT?" VII. DEVELOPMENT OF THE TELEGRAPH SYSTEM VIII. TELEGRAPHING BENEATH THE SEA IX. THE PIONEER ATLANTIC CABLE X. A SUCCESSFUL CABLE ATTAINED XI. ALEXANDER GRAHAM BELL, THE YOUTH XII. THE BIRTH OF THE TELEPHONE XIII. THE TELEPHONE AT THE CENTENNIAL XIV. IMPROVEMENT AND EXPANSION XV. TELEGRAPHING WITHOUT WIRES XVI. AN ITALIAN BOY'S WORK XVII. WIRELESS TELEGRAPHY ESTABLISHED XVIII. THE WIRELESS SERVES THE WORLD XIX. SPEAKING ACROSS THE CONTINENT XX. TELEPHONING THROUGH SPACE APPENDIX A APPENDIX B INDEX ILLUSTRATIONS SAMUEL FINLEY BREESE MORSE MORSE'S FIRST TELEGRAPH INSTRUMENT CYRUS W. FIELD WILLIAM THOMSON (LORD KELVIN) THE "GREAT EASTERN" LAYING THE ATLANTIC CABLE, 1866 ALEXANDER GRAHAM BELL THOMAS A. WATSON PROFESSOR BELL'S VIBRATING REED PROFESSOR BELL'S FIRST TELEPHONE THE FIRST TELEPHONE SWITCHBOARD USED IN NEW HAVEN, CONN., FOR EIGHT SUBSCRIBERS EARLY NEW YORK EXCHANGE PROFESSOR BELL IN SALEM, MASS., AND MR. WATSON IN BOSTON, DEMONSTRATING THE TELEPHONE BEFORE AUDIENCES IN 1877 DOCTOR BELL AT THE TELEPHONE OPENING THE NEW YORK-CHICAGO LINE, OCTOBER 18, 1892 GUGLIELMO MARCONI A REMARKABLE PHOTOGRAPH TAKEN OUTSIDE OF THE CLIFDEN STATION WHILE MESSAGES WERE BEING SENT ACROSS TO CAPE RACE MARCONI STATION AT CLIFDEN, IRELAND PREFACE This is the story of talking at a distance, of sending messages through space. It is the story of great men--Morse, Thomson, Bell, Marconi, and others--and how, with the aid of men like Field, Vail, Catty, Pupin, the scientist, and others in both the technical and commercial fields, they succeeded in flashing both messages and speech around the world, with wires and without wires. It is the story of how the thought of the world has been linked together by those modern wonders of science and of industry--the telegraph, the submarine cable, the telephone, the wireless telegraph, and, most recently, the wireless telephone. The story opens with the primitive methods of message-sending by fire or smoke or other signals. The life and experiments of Morse are then pictured and the dramatic story of the invention and development of the telegraph is set forth. The submarine cable followed with the struggles of Field, the business executive, and Thomson, the inventor and scientific expert, which finally culminated in success when the _Great Eastern_ landed a practical cable on the American coast. The early life of Alexander Graham Bell was full of color, and I have told the story of his patient investigations of human speech and hearing, which, finally culminated in a practical telephone. There follows the fascinating story of Marconi and the wireless telegraph. Last comes the story of the wireless telephone, that newest wonder which has come among us so recently that we can scarcely realize that it is here. An inner view of the marvelous development of the telephone is added in an appendix. The part played by the great business leaders who have developed and extended the new inventions, placing them at the service of all, has not been forgotten. Not only have means of communication been discovered, but they have been improved and put to the widest practical use with remarkable efficiency and celerity. The stories of these developments, in both the personal and executive sides, embody the true romance of the modern business world. The great scientists and engineers who have wrought these wonders which have had so profound an influence upon the life of the world lived, and are living, lives filled with patient effort, discouragement, accomplishment, and real romance. They are interesting men who have done interesting things. Better still, they have done important, useful things. This book relates their life stories in a connected form, for they have all worked for a similar end. The story of these men, who, starting in early youth in the pursuit of a great idea, have achieved fame and success and have benefited civilization, cannot but be inspiring. They did not stumble upon their discoveries by any lucky accident. They knew what they sought, and they labored toward the goal with unflagging zeal. Had they been easily discouraged we might still be dependent upon the semaphore and the pony express for the transmission of news. But they persevered until success was attained, and in the account of their struggle to success every one may find encouragement in facing his own tasks. One can scarce overestimate the value of modern methods of communication to the world. So much of our development has been more or less directly dependent upon it that it is difficult to fancy our situation without the telegraph and telephone. The diligence with which the ancients sought speedy methods for the sending of messages demonstrates the human need for them. The solution of this great problem, though long delayed, came swiftly, once it was begun. Even the simple facts regarding "Masters of Space" and their lives of struggle and accomplishment in sending messages between distant points form an inspiring story of great achievement. W.K.T. #MASTERS OF SPACE# I COMMUNICATION AMONG THE ANCIENTS Signaling the Fall of Troy--Marine Signaling among the Argonauts--Couriers of the Greeks, Romans, and Aztecs--Sound-signaling--Stentorophonic Tube--The Shouting Sentinels--The Clepsydra--Signal Columns--Indian Fire and Smoke Signals. It was very early in the history of the world that man began to feel the urgent need of communicating with man at a distance. When village came into friendly contact with village, when nations began to form and expand, the necessity of sending intelligence rapidly and effectively was clearly realized. And yet many centuries passed without the discovery of an effective system. Those discoveries were to be reserved for the thinkers of our age. We can understand the difficulties that beset King Agamemnon as he stood at the head of his armies before the walls of Troy. Many were the messages he would want to send to his native kingdom in Greece during the progress of the siege. Those at home would be eager for news of the great enterprise. Many contingencies might arise which would make the need for aid urgent. Certainly Queen Clytemnestra eagerly awaited word of the fall of the city. Yet the slow progress of couriers must be depended upon. One device the king hit upon which was such as any boy might devise to meet the simplest need. "If I can go skating tonight," says Johnny Jones to his chum, "I'll put a light in my window." Such is the simple device which has been used to bear the simplest message for ages. So King Agamemnon ordered beacon fires laid on the tops of Mount Ida, Mount Athos, Mount Cithæron, and on intervening eminences. Beside them he placed watchers who were always to have their faces toward Troy. When Troy fell a near-by fire was kindled, and beacon after beacon sprang into flame on the route toward Greece. Thus was the message of the fall of Troy quickly borne to the waiting queen by this preconceived arrangement. Yet neither King Agamemnon nor his sagest counselors could devise an effective system for expediting their messages. Prearranged signals were used to convey news in even earlier times. Fire, smoke, and flags were used by the Egyptians and the Assyrians previous to the Trojan War. The towers along the Chinese Wall were more than watch-towers; they were signal-towers. A flag or a light exhibited from tower to tower would quickly convey a certain message agreed upon in advance. Human thought required a system which could convey more than one idea, and yet skill in conveying news grew slowly. Perhaps the earliest example of marine signaling of which we know is recorded of the Argonautic Expedition. Theseus devised the use of colored sails to convey messages from ship to ship of the fleet, and caused the death of his father by his failure to handle the signals properly. Theseus sailed into conflict with the enemy with black sails set, a signal of battle and of death. With the battle over and himself the victor, he forgot to lower the black flag and set the red flag of victory. His father, the aged Ægeus, seeing the black flag, believed it reported his son's death, and, flinging himself into the sea, was drowned. In time it occurred to the great monarchs as their domains extended to establish relays of couriers to bear the messages which must be carried. Such systems were established by the Greeks, the Romans, and the Aztecs. Each courier would run the length of his own route and would then shout or pass the message to the next runner, who would speed it away in turn. Such was the method employed by our own pony-express riders. An ancient Persian king thought of having the messages shouted from sentinel to sentinel, instead of being carried more slowly by relays of couriers. So he established sentinels at regular intervals within hearing of one another, and messages were shouted from one to the other. Just fancy the number of sentinels required to establish a line between distant cities, and the opportunities for misunderstanding and mistake! The ancient Gauls also employed this method of communication. Cæsar records that the news of the massacre of the Romans at Orleans was sent to Auvergne, a distance of nearly one hundred and fifty miles, by the same evening. Though signaling by flashes of light occurred to the ancients, we have no knowledge that they devised a way of using the light-flashes for any but the simplest prearranged messages. The mirrors of the Pharaohs were probably used to flash light for signal purposes. We know that the Persians applied them to signaling in time of war. It is reported that flashes from the shields were used to convey news at the battle of Marathon. These seem to be the forerunners of the heliograph. But the heliograph using the dot-and-dash system of the Morse code can be used to transmit any message whatever. The ancients had evolved systems by which any word could be spelled, but they did not seem to be able to apply them practically to their primitive heliographs. An application of sound-signaling was worked out for Alexander the Great, which was considered one of the scientific wonders of antiquity. This was called a stentorophonic tube, and seems to have been a sort of gigantic megaphone or speaking-trumpet. It is recorded that it sent the voice for a dozen miles. A drawing of this strange instrument is preserved in the Vatican. Another queer signaling device, built and operated upon a novel principle, was an even greater wonder among the early peoples. This was known as a clepsydra. Fancy a tall glass tube with an opening at the bottom in which a sort of faucet was fixed. At varying heights sentences were inscribed about the tube. The tube, being filled with water, with, a float at the top, all was ready for signaling any of the messages inscribed on the tube to a station within sight and similarly equipped. The other station could be located as far away as a light could be seen. The station desiring to send a message to another exhibited its light. When the receiving station showed its light in answer, the tap was opened at the bottom of the tube in each station. When the float dropped until it was opposite the sentence which it was desired to transmit, the sending station withdrew its light and closed the tap. This was a signal for the receiving station to stop the flow of water from its tube. As the tubes were just alike, and the water had flowed out during the same period at equal speed, the float at the receiving station then rested opposite the message to be conveyed. Many crude systems of using lights for signaling were employed. Lines of watch-towers were arranged which served as signal-stations. The ruins of the old Roman and Gallic towers may still be found In France. Hannibal erected them in Africa and Spain. Colored tunics and spears were also used for military signals in the daytime. For instance, a red tunic displayed meant prepare for battle; while a red spear conveyed the order to sack and devastate. An ancient system of camp signals from columns is especially interesting as showing a development away from the prearranged signals of limited application. For these camp signals the alphabet was divided into five or six parts, and a like number of columns erected at each signal-station. Each column represented one group of letters. Suppose that we should agree to get along without the Q and the Z and reduce our own alphabet to twenty-four letters for use in such a system. With six columns we would then have four letters for each column. The first column would be used to signal A, B, C, and D. One light or flag shown from column one would represent A, two flags or lights B, and so on. Thus any word could be spelled out and any message sent. Without doubt the system was slow and cumbersome, but it was a step in the right direction. The American Indians developed methods of transmitting news which compare very favorably with the means employed by the ancients. Smoke-rings and puffs for the daytime, and fire-arrows at night, were used by them for the sending of messages. Smoke signals are obtained by building a fire of moist materials. The Indian obtains his smoke-puffs by placing a blanket or robe over the fire, withdrawing it for an instant, and then replacing it quickly. In this way puffs of smoke may be sent aloft as frequently as desired. A column of smoke-puffs was used as a warning signal, its meaning being: Look out, the enemy is near. One smoke-puff was a signal for attention; two puffs indicated that the sender would camp at that place. Three puffs showed that the sender was in danger, as the enemy was near. Fire-arrows shot across the sky at night had a similar meaning. The head of the arrow was dipped in some highly inflammable substance and then set on fire at the instant before it was discharged from the bow. One fire-arrow shot into the sky meant that the enemy were near; two signaled danger, and three great danger. When the Indian shot many fire-arrows up in rapid succession he was signaling to his friends that his enemies were too many for him. Two arrows discharged into the air at the same time indicated that the party sending them was about to attack. Three indicated an immediate attack. A fire-arrow discharged diagonally across the sky indicated the direction in which the sender would travel. Such were the methods which the Indians used, working out different meanings for the signals in the various tribes. Very slight progress was made in message-sending in medieval times, and it was the middle of the seventeenth century before even signal systems were attained which were in any sense an improvement. For many centuries the people of the world existed, devising nothing better than the primitive methods outlined above. II SIGNALS PAST AND PRESENT Marine and Military Signals--Code Flags--Wig-wag--Semaphore Telegraphs--Heliographs--Ardois Signals--Submarine Signals. In naval affairs some kind of an effective signal system is imperative. Even in the ordinary evolutions of a fleet the commander needs some better way of communicating with the ship captains than despatching a messenger in a small boat. The necessity of quick and sure signals in time of battle is obvious. Yet for many centuries naval signals were of the crudest. The first distinct advance over the primitive methods by which the commander of one Roman galley communicated with another came with the introduction of cannon as a naval arm. The use of signal-guns was soon thought of, and war-ships used their guns for signal purposes as early as the sixteenth century. Not long after came the square-rigged ship, and it soon occurred to some one that signals could be made by dropping a sail from the yard-arm a certain number of times. Up to the middle of the seventeenth century the possibilities of the naval signal systems were limited indeed. Only a few prearranged orders and messages could be conveyed. Unlimited communication at a distance was still impossible, and there were no means of sending a message to meet an unforeseen emergency. So cumbersome were the signal systems in use that even though they would convey the intelligence desired, the speaking-trumpet or a courier was employed wherever possible. To the officers of the British navy of the seventeenth century belongs the credit for the first serious attempt to create a system of communication which would convey any and all messages. It is not clear whether Admiral Sir William Penn or James II. established the code. It was while he was Duke of York and the commander of Britain's navy, that the James who was later to be king took this part in the advancement of means of communication. Messages were sent by varying the position of a single signal flag. In 1780 Admiral Kempenfeldt thought of adding other signal flags instead of depending upon the varied positions of a single signal. From his plan the flag signals now in use by the navies of the world were developed. The basis of his system was the combining of distinct flags in pairs. The work of Admiral Philip Colomb marked another long step forward in signaling between ships. While a young officer he developed a night-signal system of flashing lights, still in use to some extent, and which bears his name. Colomb's most important contribution to the art of signaling was his realization of the utility of the code which Morse had developed in connection with the telegraph. Code flags, which are largely used between ships, have not been entirely displaced by the wireless. The usual naval code set consists of a set of alphabet flags and pennants, ten numeral flags, and additional special flags. This of course provides for spelling out any conceivable message by simply hoisting letter after letter. So slow a method is seldom used, however. Various combinations of letters and figures are used to indicate set terms or sentences set forth in the code-book. Thus the flags representing A and E, hoisted together, may be found on reference to the code-book to mean, "Weigh anchor." Each navy has its own secret code, which is carefully guarded lest it be discovered by a possible enemy. Naval code-books are bound with metal covers so that they may be thrown overboard in case a ship is forced to surrender. The international code is used by ships of all nations. It is the universal language of the sea, and by it sailors of different tongues may communicate through this common medium. Any message may be conveyed by a very few of the flags in combination. The wig-wag system, a favorite and familiar method of communication with every Boy Scout troop, is in use by both army and navy. The various letters of the alphabet are indicated by the positions in which the signaler holds his arms. Keeping the arms always forty-five degrees apart, it is possible to read the signals at a considerable distance. Navy signalers have become very efficient with this form of communication, attaining a speed of over fifteen words a minute. A semaphore is frequently substituted for the wig-wag flags both on land and on sea. Navy semaphores on big war-ships consist of arms ten or twelve feet long mounted at the masthead. The semaphore as a means of communication was extensively used on land commercially as well as by the army. A regular semaphore telegraph system, working in relays over considerable distances was in operation in France a century ago. Other semaphore telegraphs were developed in England. The introduction of the Morse code and its adaptation to signaling by sight and sound did much to simplify these means of communication. The development of signaling after the adoption of the Morse code, though it occurred subsequent to the introduction of the telegraph, may properly be spoken of here, since the systems dependent upon sight and sound grow from origins more primitive than those which depend upon electricity. Up to the middle of the nineteenth century armies had made slight progress in perfecting means of communication. The British army had no regular signal service until after the recommendations of Colomb proved their worth in naval affairs. The German army, whose systems of communication have now reached such perfection, did not establish an army signal service until 1902. The simplicity of the dot and dash of the Morse code makes it readily available for almost any form of signaling under all possible conditions. Two persons within sight of each other, who understand the code, may establish communication by waving the most conspicuous object at hand, using a short swing for a dot and a long swing for a dash. Two different shapes may also be exhibited, one representing a dot and the other a dash. The dot-and-dash system is also admirably adapted for night signaling. A search-light beam may be swung across the sky through short and long arcs, a light may be exhibited and hidden for short and long periods, and so on. Where the search-light may be played upon a cloud it may be seen for very considerable distances, messages having been sent forty miles by this means. Fog-horns, whistles, etc., may be similarly employed during fogs or amid thick smoke. A short blast represents a dot, and a long one a dash. The heliograph, which established communication by means of short and long light-flashes, is another important means of signaling to which the Morse code has been applied. This instrument catches the rays of the sun upon a mirror, and thence casts them to a distant receiving station. A small key which throws the mirror out of alignment serves to obscure the flashes for a space at the will of the sender, and so produces short or long flashes. The British army has made wide use of the heliograph in India and Africa. During the British-Boer War It formed the sole means of communication between besieged garrisons and the relief forces. Where no mountain ranges intervene and a bright sun is available, heliographic messages may be read at a distance of one hundred and fifty miles. While the British navy used flashing lights for night signals, the United States and most other navies adopted a system of fixed colored lights. The system in use in the United States Navy is known as the Ardois system. In this system the messages are sent by four lights, usually electric, which are suspended from a mast or yard-arm. The lights are manipulated by a keyboard situated at a convenient point on the deck. A red lamp is flashed to indicate a dot in the Morse code, while a white lamp indicates a dash. The Ardois system is also used by the Army. The perfection of wireless telegraphy has caused the Ardois and other signal systems depending upon sight or sound to be discarded in all but exceptional cases. The wig-wag and similar systems will probably never be entirely displaced by even such superior systems as wireless telegraphy. The advantage of the wig-wag lies in the fact that no apparatus is necessary and communication may thus be established for short distances almost instantly. Its disadvantages are lack of speed, impenetrability to dust, smoke, and fog, and the short ranges over which it may be operated. There is another form of sound-signaling which, though it has been developed in recent years, may properly be mentioned in connection with earlier signal systems of similar nature. This is the submarine signal. We have noted that much attention was paid to communication by sound-waves through the medium of the air from the earliest times. It was not until the closing years of the past century, however, that the superior possibilities of water as a conveyer of sound were recognized. Arthur J. Mundy, of Boston, happened to be on an American steamer on the Mississippi River in the vicinity of New Orleans. It was rumored that a Spanish torpedo-boat had evaded the United States war vessels and made its way up the great river. The general alarm and the impossibility of detecting the approach of another vessel set Mundy thinking. It seemed to him that there should be some way of communicating through the water and of listening for sounds underwater. He recalled his boyhood experiments in the old swimming-hole. He remembered how distinctly the sound of stones cracked together carried to one whose ears were beneath the surface. Thus the idea of underwater signaling was born. Mundy communicated this idea to Elisha Gray, and the two, working together, evolved a successful submarine signal system. It was on the last day of the nineteenth century that they were able to put their experiments into practical working form. Through a well in the center of the ship they suspended an eight-hundred-pound bell twenty feet beneath the surface of the sea. A receiving apparatus was located three miles distant, which consisted simply of an ear-trumpet connected to a gas-pipe lowered into the sea. The lower end of the pipe was sealed with a diaphragm of tin. When submerged six feet beneath the surface the strokes of the bell could be heard. Then a special electrical receiver of extreme sensitiveness, known as a microphone, was substituted and connected at the receiving station with an ordinary telephone receiver. With this receiving apparatus the strokes of the bell could be heard at a distance of over ten miles. This system has had a wide practical application for communication both between ship and ship and between ship and shore. Most transatlantic ships are now equipped with such a system. The transmitter consists of a large bell which is actuated either by compressed air or by an electro-magnetic system. This is so arranged that it may be suspended over the side of the ship and lowered well beneath the surface of the water. The receivers consist of microphones, one on each side of the ship. The telephone receivers connected to the two microphones are mounted close together on an instrument board on the bridge of the ship. The two instruments are used when it is desired to determine the direction from which the signals come. If the sound is stronger in the 'phone on the right-hand side of the ship the commander knows that the signals are coming from that direction. If the signals are from a ship in distress he may proceed toward it by turning his vessel until the sound of the signal-bell is equal in the two receivers. The ability to determine the direction from which the signal comes is especially valuable in navigating difficult channels in foggy weather. Signal-bells are located near lighthouses and dangerous reefs. Each calls its own number, and the vessel's commander may thus avoid obstructions and guide the ship safely into the harbor. The submarine signal is equally useful in enabling vessels to avoid collision in fogs. Because water conducts sound much better than air, submarine signals are far better than the fog-horn or whistles. The submarine signal system has also been applied to submarine war-ships. By this means alone may a submarine communicate with another, with a vessel on the surface, or with a shore station. An important and interesting adaptation of the marine signal was made to meet the submarine warfare of the great European conflict. At first it seemed that battle-ship and merchantman could find no way to locate the approach of an enemy submarine. But it was found that by means of the receiving apparatus of the submarine telephone an approaching submarine could be heard and located. While the sounds of the submarine's machinery are not audible above the water, the delicate microphone located beneath the water can detect them. Hearing a submarine approaching beneath the surface, the merchantman may avoid her and the destroyers and patrol-boats may take means to effect her capture. III FORERUNNERS OF THE TELEGRAPH From Lodestone to Leyden Jar--The Mysterious "C.M."--Spark and Frictional Telegraphs--The Electro-magnet--Davy and the Relay System. The thought and effort directed toward improving the means of communication brought but small results until man discovered and harnessed for himself a new servant--electricity. The story of the growth of modern means of communication is the story of the application of electricity to this particular one of man's needs. The stories of the Masters of Space are the stories of the men who so applied electricity that man might communicate with man. Some manifestations of electricity had been known since long before the Christian era. A Greek legend relates how a shepherd named Magnes found that his crook was attracted by a strange rock. Thus was the lodestone, the natural magnetic iron ore, discovered, and the legend would lead us to believe that the words magnet and magnetism were derived from the name of the shepherd who chanced upon this natural magnet and the strange property of magnetism. The ability of amber, when rubbed, to attract straws, was also known to the early peoples. How early this property was found, or how, we do not know. The name electricity is derived from _elektron_, the Greek name for amber. The early Chinese and Persians knew of the lodestone, and of the magnetic properties of amber after it has been rubbed briskly. The Romans were familiar with these and other electrical effects. The Romans had discovered that the lodestone would attract iron, though a stone wall intervened. They were fond of mounting a bit of iron on a cork floating in a basin of water and watch it follow the lodestone held in the hand. It is related that the early magicians used it as a means of transmitting intelligence. If a needle were placed upon a bit of cork and the whole floated in a circular vessel with the alphabet inscribed about the circle, one outside the room could cause the needle to point toward any desired letters in turn by stepping to the proper position with the lodestone. Thus a message could be sent to the magician inside and various feats of magic performed. Our own modern magicians are reported as availing themselves of the more modern applications of electricity in somewhat similar fashion and using small, easily concealed wireless telegraph or telephone sets for communication with their confederates off the stage. The idea of encircling a floating needle with the alphabet was developed into the sympathetic telegraph of the sixteenth century, which was based on a curious error. It was supposed that needles which had been touched by the same lodestone were sympathetic, and that if both were free to move one would imitate the movements of another, though they were at a distance. Thus, if one needle were attracted toward one letter after the other, and the second similarly mounted should follow its movements, a message might readily be spelled out. Of course the second needle would not follow the movements of the first, and so the sympathetic telegraph never worked, but much effort was expended upon it. In the mean time others had learned that many substances besides amber, on being rubbed, possessed magnetic properties. Machines by which electricity could be produced in greater quantities by friction were produced and something was learned of conductors. Benjamin Franklin sent aloft his historic kite and found that electricity came down the silken cord. He demonstrated that frictional and atmospheric electricity are the same. Franklin and others sent the electric charge along a wire, but it did not occur to them to endeavor to apply this to sending messages. Credit for the first suggestion of an electric telegraph must be given to an unknown writer of the middle eighteenth century. In the _Scots Magazine_ for February 17, 1755, there appeared an article signed simply, "C.M.," which suggested an electric telegraph. The writer's idea was to lay an insulated wire for each letter of the alphabet. The wires could be charged from an electrical machine in any desired order, and at the receiving end would attract disks of paper marked with the letter which that wire represented, and so any message could be spelled out. The identity of "C.M." has never been established, but he was probably Charles Morrison, a Scotch surgeon with a reputation for electrical experimentation, who later emigrated to Virginia. Of course "C.M.'s" telegraph was not practical, because of the many wires required, but it proved to be a fertile suggestion which was followed by many other thinkers. One experimenter after another added an improvement or devised a new application. A French scientist devised a telegraph which it is suspected might have been practical, but he kept his device secret, and, as Napoleon refused to consider it, it never was put to a test. An Englishman devised a frictional telegraph early in the last century and endeavored to interest the Admiralty. He was told that the semaphore was all that was required for communication. Another submitted a similar system to the same authorities in 1816, and was told that "telegraphs of any kind are now wholly unnecessary." An American inventor fared no better, for one Harrison Gray Dyar, of New York, was compelled to abandon his experiments on Long Island and flee because he was accused of conspiracy to carry on secret communication, which sounded very like witchcraft to our forefathers. His telegraph sent signals by having the electric spark transmitted by the wire decompose nitric acid and so record the signals on moist litmus paper. It seems altogether probable that had not the discovery of electro-magnetism offered improved facilities to those seeking a practical telegraph, this very chemical telegraph might have been put to practical use. In the early days of the nineteenth century the battery had come into being, and thus a new source of electric current was available for the experimenters. Coupled with this important discovery in its effect upon the development of the telegraph was the discovery of electro-magnetism. This was the work of Hans Christian Oersted, a native of Denmark. He first noticed that a current flowing through a wire would deflect a compass, and thus discovered the magnetic properties of the electric current. A Frenchman named Ampère, experimenting further, discovered that when the electric current is sent through coils of wire the magnetism is increased. The possibility of using the deflection of a magnetic needle by an electric current passing through a wire as a means of conveying intelligence was quickly grasped by those who were striving for a telegraph. Experiments with spark and chemical telegraphs were superseded by efforts with this new discovery. Ampère, acting upon the suggestion of La Place, an eminent mathematician, published a plan for a feasible telegraph. This was later improved upon by others, and it was still early in the nineteenth century that a model telegraph was exhibited in London. About this time two professors at the University of Göttingen were experimenting with telegraphy. They established an experimental line between their laboratories, using at first a battery. Then Faraday discovered that an electric current could be generated in a wire by the motion of a magnet, thus laying the basis for the modern dynamo. Professors Gauss and Weber, who were operating the telegraph line at Göttingen, adapted this new discovery to their needs. They sent the message by moving a magnetic key. A current was thus generated in the line, and, passing over the wire and through a coil at the farther end, moved a magnet suspended there. The magnet moved to the right or left, depending on the direction of the current sent through the wire. A tiny mirror was mounted on the receiving magnet to magnify its movement and so render it more readily visible. One Steinheil, of Munich, simplified it and added a call-bell. He also devised a recording telegraph in which the moving needle at the receiving station marked down its message in dots and dashes on a ribbon of paper. He was the first to utilize the earth for the return circuit, using a single wire for despatching the electric current used in signaling and allowing it to return through the ground. In 1837, the same year in which Wheatstone and Morse were busy perfecting their telegraphs, as we shall see, Edward Davy exhibited a needle telegraph in London. Davy also realized that the discoveries of Arago could be used in improving the telegraph and making it practical. Arago discovered that the current passing through a coil of wire served to magnetize temporarily a piece of soft iron within it. It was this principle upon which Morse was working at this time. Davy did not carry his suggestions into effect, however. He emigrated to Australia, and the interruption in his experiments left the field open for those who were finally to bring the telegraph into usable form. Davy's greatest contribution to telegraphy was the relay system by which very weak currents could call into play strong currents from a local battery, and so make the signals apparent at the receiving station. IV INVENTIONS OF SIR CHARLES WHEATSTONE Wheatstone and His Enchanted Lyre--Wheatstone and Cooke--First Electric Telegraph Line Installed--The Capture of the "Kwaker"--The Automatic Transmitter. Before we come to the story of Samuel F.B. Morse and the telegraph which actually proved a commercial success as the first practical carrier of intelligence which had been created for the service of man, we should pause to consider the achievements of Charles Wheatstone. Together with William Fothergill Cooke, another Englishman, he developed a telegraph line that, while it did not attain commercial success, was the first working telegraph placed at the service of the public. Charles Wheatstone was born near Gloucester in 1802. Having completed his primary schooling, Charles was apprenticed to his uncle, who was a maker and seller of musical instruments. He showed little aptitude either in the workshop or in the store, and much preferred to continue the study of books. His father eventually took him from his uncle's charge and allowed him to follow his bent. He translated poetry from the French at the age of fifteen, and wrote some verse of his own. He spent all the money he could secure on books. Becoming interested in a book on Volta's experiments with electricity, he saved up his coppers until he could purchase it. It was in French, and he found the technical descriptions rather too difficult for his comprehension, so that he was forced to save again to buy a French-English dictionary. With the aid of this he mastered the volume. Immediately his attention was turned toward the wonders of the infant science of electricity, and he eagerly endeavored to perform the experiments described. Aided by his older brother, he set to work on a battery as a source of current. Running short of funds with which to purchase copper plates, he again began to save his pennies. Then the idea occurred to him to use the pennies themselves, and his first battery was soon complete. He continued his experiments in various fields until, at the age of nineteen, he first brought himself to public notice with his enchanted lyre. This he placed on exhibition in music-shops in London. It consisted of a small lyre suspended from the ceiling which gave forth, in turn, the sounds of various musical instruments. Really the lyre was merely a sounding-box, and the vibrations of the music were conveyed from instruments, played in the next room, to the lyre through a steel rod. The young man spent much time experimenting with the transmission of sound. Having conveyed music through the steel rod to his enchanted lyre, much to the mystification of the Londoners, he proposed to transmit sounds over a considerable distance by this method. He estimated that sound could be sent through steel rods at the rate of two hundred miles a second and suggested the use of such a rod as a telegraph between London and Edinburgh. He called his arrangement a telephone. A scientific writer of the day, commenting in a scientific journal on the enchanted lyre which Wheatstone had devised, suggested that it might be used to render musical concerts audible at a distance. Thus an opera performed in a theater might be conveyed through rods to other buildings in the vicinity and there reproduced. This was never accomplished, and it remained for our own times to accomplish this and even greater wonders. Wheatstone also devised an instrument for increasing feeble sound, which he called a microphone. This consisted of a pair of rods to convey the sound vibrations to the ears, and does not at all resemble the modern electrical microphone. Other inventions in the transmission and reproduction of sound followed, and he devoted no little attention to the construction of improved musical instruments. He even made some efforts to produce a practical talking-machine, and was convinced that one would be attained. At thirty-two he was widely famed as a scientist and had been made a professor of experimental physics in King's College, London. His most notable work at this time was measuring the speed of the electric current, which up to that time had been supposed to be instantaneous. By 1835 Wheatstone had abandoned his plans for transmitting sounds through long rods of metal and was studying the telegraph. He experimented with instruments of his own and proposed a line across the Thames. It was in 1836 that Mr. Cooke, an army officer home on leave, became interested in the telegraph and devoted himself to putting it on a working basis. He had already exhibited a crude set when he came to Wheatstone, realizing his own lack of scientific knowledge. The two men finally entered into partnership, Wheatstone contributing the scientific and Cooke the business ability to the new enterprise. The partnership was arranged late in 1837, and a patent taken out on Wheatstone's five-needle telegraph. In this telegraph a magnetic needle was located within a loop formed by the telegraph circuit at the receiving end. When the circuit was closed the needle was deflected to one side or the other, according to the direction of the current. Five separate circuits and needles were used, and a variety of signals could thus be sent. Five wires, with a sixth return wire, were used in the first experimental line erected in London in 1837. So in the year when Morse was constructing his models Wheatstone and Cooke were operating an experimental line, crude and impracticable though it was, and enjoying the sensations of communicating with each other at a distance. In 1841 the telegraph was placed on public exhibition at so much a head, but it was viewed as an entertaining novelty without utility by the public at large. After many disappointments the inventors secured the cooperation of the Great Western Railroad, and a line was erected for a distance of thirteen miles. But the public would not patronise the line until its utility was strikingly demonstrated by the capture of the "Kwaker." Early one morning a woman was found dead in her home in the suburbs of London. A man had been observed leaving the house, and his appearance had been noted. Inquiries revealed that a man answering his description had left on the slow train for London. Without the telegraph he could not have been apprehended. But the telegraph was available at this point, and his description was telegraphed ahead and the police in London were instructed to arrest him upon his arrival. "He is dressed as a Quaker," ran the message. There was no Q in the alphabet of-the five-needle instrument, and so the sender spelled Quaker, Kwaker. The clerk at the receiving end could not-understand the strange word, and asked to have it repeated again and again. Finally some one suggested that the message be completed and the whole was then deciphered. When the man dressed as a Quaker stepped from the slow train on his arrival at London the police were awaiting him; he was arrested and eventually confessed the murder. The news of this capture and the part the telegraph played gave striking proof of the utility of the new invention, and public skepticism and indifference were overcome. By 1845 Wheatstone had so improved his apparatus that but one wire was required. The single-needle instrument pointed out the letters on the dial around it by successive deflections in which it was arranged to move, step by step, at the will of the sending station. The single-needle instrument, though generally displaced by Morse's telegraph, remained in use for a long time on some English lines. Wheatstone had also invented a type-printing telegraph, which he patented in 1841. This required two circuits. With a working telegraph attained, the partners became involved in an altercation as to which deserved the honor of inventing the same. The quarrel was finally submitted to two famous scientists for arbitration. They reported that the telegraph was the result of their joint labors. To Wheatstone belongs the credit for devising the apparatus; to Cooke for introducing it and placing it before the public in working form. Here we see the combination of the man of science and the man of business, each contributing needed talents for the establishment of a great invention on a working basis. Wheatstone's researches in the field of electricity were constant. In 1840 he devised a magnetic clock and proposed a plan by which many clocks, located at different points, could be set at regular intervals with the aid of electricity. Such a system was the forerunner of the electrically wound and regulated clocks with which we are now so familiar. He also devised a method for measuring the resistance which wires offer to the passage of an electric current. This is known as Wheatstone's bridge and is still in use in every electrical and physical laboratory. He also invented a sound telegraph by which signals were transmitted by the strokes of a bell operated by the current at the receiving end of the circuit. The invention of Wheatstone's which proved to be of greatest lasting importance in connection with the telegraph was the automatic transmitter. By this system the message is first punched in a strip of paper which, when passed through the sending instrument, transmits the message. By this means he was able to send messages at the rate of one hundred words a minute. This automatic transmitter is much used for press telegrams where duplicate messages are to be sent to various points. The automatic transmitter brought knighthood to its inventor, Wheatstone receiving this honor in 1868. Wheatstone took an active part in the development of the telegraph and the submarine cable up to the time of his death in 1875. Wheatstone's telegraph would have served the purposes of humanity and probably have been universally adopted, had not a better one been invented almost before it was established. And it is because Morse, taking up the work where others had left off, was able to invent an instrument which so fully satisfied the requirements of man for so long a period that he is known to all of us as the inventor of the telegraph. And yet, without belittling the part played by Morse, we must recognize the important work accomplished by Sir Charles Wheatstone. V THE ACHIEVEMENT OF MORSE Morse's Early Life--Artistic Aspirations--Studies in Paris--His Paintings--Beginnings of His Invention--The First Instrument--The Morse Code--The First Written Message. When we consider the youth and immaturity of America in the first half of the nineteenth century, it seems the more remarkable that the honor of making the first great practical application of electricity should have been reserved for an American. With the exception of the isolated work of Franklin, the development of the new science of electrical learning was the work of Europeans. This was natural, for it was Europe which was possessed of the accumulated wealth and learning which are usually attained only by older civilizations. Yet, with all these advantages, electricity remained largely a scientific plaything. It was an American who fully recognized the possibilities of this new force as a servant of man, and who was possessed of the practical genius and the business ability to devise and introduce a thoroughly workable system of rapid and certain communication. We have seen that Wheatstone was early trained as a musician. Samuel Morse began life as an artist. But while Wheatstone early indicated his lack of interest in music and devoted himself to scientific studies while yet a youth, Morse's artistic career was of his own choosing, and he devoted himself to it for many years. This explains the fact that Wheatstone attained much scientific success before Morse, though he was eleven years his junior. It was in 1791 that Samuel Morse was born. Samuel Finley Breese Morse was the entire name with which he was endowed by his parents. He came from the sturdiest of Puritan stock, his father being of English and his mother of Scotch descent. His father was an eminent divine, and also notable as a geographer, being the author of the first American geography of importance. His mother also was possessed of unusual talent and force. It is interesting to note that Samuel Morse first saw the light in Charlestown, Massachusetts, at the foot of Breed's Hill, but little more than a mile from the birthplace of Benjamin Franklin. He came into the world about a year after Franklin died. It is interesting to believe that some of the practical talent of America's first great electrician in some way descended to Samuel Morse. He received an unusual education. At the age of seven he was sent to a school at Andover, Massachusetts, to prepare him for Phillips Academy. At the academy he was prepared for Yale College, which he entered when fifteen years of age. With the knowledge of science so small at the time, collegiate instruction in such subjects was naturally meager in the extreme. Jeremiah Day was then professor of natural philosophy at Yale, and was probably America's ablest teacher of the subject. His lectures upon electricity and the experiments with which he illustrated them aroused the interest of Morse, as we learn from the letters he wrote to his parents at this time. One principle in particular impressed Morse. This was that "if the electric circuit be interrupted at any place the fluid will become visible, and when it passes it will leave an impression upon any intermediate body." Thus was it stated in the text-book in use at Yale at that time. More than a score of years after the telegraph had been achieved Morse wrote: The fact that the presence of electricity can be made visible in any desired part of the circuit was the crude seed which took root in my mind, and grew into form, and ripened into the invention of the telegraph. We shall later hear of the occasion which recalled this bit of information to Morse's mind. But though Yale College was at that time a center of scientific activity, and Morse showed more than a little interest in electricity and chemistry, his major interest remained art. He eagerly looked forward to graduation that he might devote his entire time to the study of painting. It is significant of the tolerance and breadth of vision of his parents that they apparently put no bars in the path of this ambition, though they had sacrificed to give him the best of collegiate trainings that he might fit himself for the ministry, medicine, or the law. As a boy of fifteen Samuel Morse had painted water-colors that attracted attention, and he was possessed of enough talent to paint miniatures while at Yale which were salable at five dollars apiece, and so aided in defraying his college expenses. After his graduation from Yale in 1810, Morse devoted himself entirely to the study of art, still being dependent upon his parents for support. He secured the friendship and became the pupil of Washington Allston, then a foremost American painter. In the summer of 1811 Allston sailed for England, and Morse accompanied him. In London he came to the attention of Benjamin West, then at the height of his career, and benefited by his advice and encouragement. That he had no ambition other than his art at this period we may learn from a letter he wrote to his mother in 1812. My passion for my art [he wrote] is so firmly rooted that I am confident no human power could destroy it. The more I study the greater I think is its claim to the appellation divine. I am now going to begin a picture of the death of Hercules, the figure to be large as life. When he had completed this picture to his own satisfaction, he showed it to West. "Go on and finish it," was West's comment. "But it is finished," said Morse. "No, no. See here, and here, and here are places you can improve it." Morse went to work upon his painting again, only to meet the same comment when he again showed it to West. This happened again and again. When the youth had finally brought it to a point where West was convinced it was the very best Morse could do he had learned a lesson in thoroughness and painstaking attention to detail that he never forgot. That he might have a model for his painting Morse had molded a figure of Hercules in clay. At the advice of West he entered the cast in a competition for a prize in sculpture, with the result that he received the prize and a gold medal for his work. He then plunged into the competition for a prize and medal offered by the Royal Academy for the best historical painting. His subject was, "The Judgment of Jupiter in the Case of Apollo, Marpessa, and Idas." Though he completed the picture to the satisfaction of West, Morse was not able to remain in London and enter it in the competition. The rules required that the artist be present in person if he was to receive the prize, but Morse was forced to return to America. He had been in England for four years--a year longer than had originally been planned for him--and he was out of funds, and his parents could support him no longer. Morse lived in London during the War of 1812, but seems to have suffered no annoyance other than that of poverty, which the war intensified by raising the prices of food as well as his necessary artist's materials to an almost prohibitive figure. The last of the Napoleonic wars was also in progress. News of the battle of Waterloo reached London but a short time before Morse sailed for America. It required two days for the news to reach the English capital. The young American, whose inability to sell his paintings was driving him from London, was destined to devise a system which would have carried the great news to its destination within a few seconds. But while he gained fame in America and secured praise and attention as he had in London, he found art no more profitable. He contrived to eke out an existence by painting an occasional portrait, going from town to town in New England for this purpose. He turned from art to invention for a time, joining with his brother in devising a fire-engine pump of an improved pattern. They secured a patent upon it, but could not sell it. He turned again to the life of a wandering painter of portraits. In 1818 he went to Charleston, South Carolina, at the invitation of his uncle. His portraits proved very popular and he was soon occupied with work at good prices. This prosperity enabled him to take unto himself a wife, and the same year he married Lucretia Walker, of Concord, New Hampshire. After four years in the South Morse returned to the North, hoping that larger opportunities would now be ready for him. The result was again failure. He devoted his time to huge historical paintings, and the public would neither buy them nor pay to see them when they were exhibited. Another blow fell upon him in 1825 when his wife died. At last he began to secure more sitters for his portraits, though his larger works still failed. He assisted in the organization of the National Academy of Design and became its first president. In 1829 he again sailed for Europe to spend three years in study in the galleries of Paris and Rome. Still he failed to attain any real success in his chosen work. He had made many friends and done much worthy work, yet there is little probability that he would have attained lasting fame as an artist even though his energies had not been turned to other interests. It was on the packet ship _Sully_, crossing the Atlantic from France, that Morse conceived the telegraph which was to prove the first great practical application of electricity. One noon as the passengers were gathered about the luncheon-table, a Dr. Charles T. Jackson, of Boston, exhibited an electro-magnet he had secured in Europe, and described certain electrical experiments he had seen while in Paris. He was asked concerning the speed of electricity through a wire, and replied that, according to Faraday, it was practically instantaneous. The discussion recalled to Morse his own collegiate studies in electricity, and he remarked that if the circuit were interrupted the current became visible, and that it occurred to him that these flashes might be used as a means of communication. The idea of using the current to carry messages became fixed in his mind, and he pondered, over it during the remaining weeks of the long, slow voyage. Doctor Jackson claimed, after Morse had perfected and established his telegraph, that the idea had been his own, and that Morse had secured it from him on board the _Sully_. But Doctor Jackson was not a practical man who either could or did put any ideas he may have had to practical use. At the most he seems to have simply started Morse's mind along a new train of thought. The idea of using the current as a carrier of messages, though it was new to Morse, had occurred to others earlier, as we have seen. But at the very outset Morse set himself to find a means by which he might make the current not only signal the message, but actually record it. Before he landed from the _Sully_ he had worked out sketches of a printing telegraph. In this the current actuated an electro-magnet on the end of which was a rod. This rod was to mark down dots and dashes on a moving tape of paper. Thus was the idea born. Of course the telegraph was still far from an accomplished fact. Without the improved electro-magnets and the relay of Professor Henry, Morse had not yet even the basic ideas upon which a telegraph to operate over considerable distances could be constructed. But Morse was possessed of Yankee imagination and practical ability. He was possessed of a fair technical education for that day, and he eagerly set himself to attaining the means to accomplish his end. That he realized just what he sought is shown by his remark to the captain of the _Sully_ when he landed at New York. "Well, Captain," he remarked, "should you hear of the telegraph one of these days as the wonder of the world, remember that the discovery was made on board the good ship _Sully_." With the notion of using an electro-magnet as a receiver, an alphabet consisting of dots and dashes, and a complete faith in the practical possibilities of the whole, Morse went to work in deadly earnest. But poverty still beset him and it was necessary for him to devote most of his time to his paintings, that he might have food, shelter, and the means to buy materials with which to experiment. From 1832 to 1835 he was able to make but small progress. In the latter year he secured an appointment as professor of the literature of the arts of design in the newly established University of the City of New York. He soon had his crude apparatus set up in a room at the college and in 1835 was able to transmit messages. He now had a little more leisure and a little more money, but his opportunities were still far from what he would have desired. The principal aid which came to him at the university was from Professor Gale, a teacher of chemistry. Gale became greatly interested in Morse's apparatus, and was able to give him much practical assistance, becoming a partner in the enterprise. Morse knew little of the work of other experimenters in the field of electricity and Gale was able to tell Morse what had been learned by others. Particularly he brought to Morse's attention the discoveries of another American, Prof. Joseph Henry. The electro-magnet which actuated the receiving instrument in the crude set in use by Morse in 1835 had but a few turns of thick wire. Professor Henry, by his experiments five years earlier, had demonstrated that many turns of small wire made the electro-magnet far more sensitive. Morse made this improvement in his own apparatus. In 1832 Henry had devised a telegraph very similar to that of Morse by which he signaled through a mile of wire. His receiving apparatus was an electro-magnet, the armature of which struck a bell. Thus the messages were read by sound, instead of being recorded on a moving strip of paper as by Morse's system. While Henry was possibly the ablest of American electricians at that time, he devoted himself entirely to science and made no effort to put his devices to practical use. Neither did he endeavor to profit by his inventions, for he secured no patents upon them. Professor Henry realized, in common with Morse and others, that if the current were to be conducted over long wires for considerable distances it would become so weak that it would not operate a receiver. Henry avoided this difficulty by the invention of what is known as the relay. At a distance where the current has become weak because of the resistance of the wire and losses due to faulty insulation, it will still operate a delicate electro-magnet with a very light armature so arranged as to open and close a local circuit provided with suitable batteries. Thus the recording instrument may be placed on the local circuit and as the local circuit an opened and closed in unison with the main circuit, the receiver can be operated. It was the relay which made it possible to extend telegraph lines to a considerable distance. It is not altogether clear whether Morse adopted Henry's relay or devised it for himself. It is believed, however, that Professor Henry explained the relay to Professor Gale, who in turn placed it before his partner, Morse. By 1837 Morse had completed a model, had improved his apparatus, had secured stronger batteries and longer wires, and mastered the use of the relay. It was in this year that the House of Representatives ordered the Secretary of the Treasury to investigate the feasibility of establishing a system of telegraphs. This action urged Morse to complete his apparatus and place it before the Government. He was still handicapped by lack of money, lack of scientific knowledge, and the difficulty of securing necessary materials and devices. To-day the experimenter may buy wire, springs, insulators, batteries, and almost anything that might be useful. Morse, with scanty funds and limited time, had to search for his materials and puzzle out the way to make each part for himself with such crude tools as he had available. Need we wonder that his progress was slow? Instead we should wonder that, despite all discouragements and handicaps, he clung to his great idea and labored on. But assistance was to come to him in this same eventful year of 1837, and that quite unexpectedly. On a Saturday in September a young man named Alfred Vail wandered into Professor Gale's laboratory. Morse was there engaged in exhibiting his model to an English professor then visiting in New York. The youth was deeply impressed with what he saw. He realized that here were possibilities of an instrument that would be of untold service to mankind. Asking Professor Morse whether he intended to experiment with a longer line, he was informed that such was his intention as soon as he could secure the means. Young Vail replied that he thought he could secure the money if Morse would admit him as a partner. To this Morse assented. Vail plunged into the enterprise with all the enthusiasm of youth. That very evening he studied over the commercial possibilities, and before he retired had marked out on the maps in his atlas the routes for the most needed lines of communication. The young man applied to his father for support. The senior Vail was the head of the Speedwell Iron Works at Morristown, New Jersey, and was a man of unusual enterprise and ability. He determined to back his son in the enterprise, and Morse was invited to come and exhibit his model. Two thousand dollars was needed to make the necessary instruments and secure the patents. On September 23, 1837, the agreement was drawn up by the terms of which Alfred Vail was, at his own expense, to construct apparatus suitable for exhibition to Congress and to secure a patent. In return he was to receive a one-fourth interest. Very shortly afterward they filed a caveat in the Patent Office, which is a notice serving to protect an impending invention. Alfred Vail immediately set to work on the apparatus, his only helper being a fifteen-year-old apprentice boy named William Baxter. The two worked early and late for many months in a secret room in the iron-works, being forced to fashion every part for themselves. The first machine was a copy of Morse's model, but Vail's native ability as a mechanic and his own ingenuity enabled him to make many improvements. The pencil fastened to the armature which had marked zigzag lines on the moving paper was replaced by a fountain-pen which inscribed long and short lines, and thus the dashes and dots of the Morse code were put into their present form. Morse had worked out an elaborate telegraphic code or dictionary, but a simpler code by which combinations of dots and dashes were used to represent letters instead of numbers in a code was now devised. Vail recognized the importance of having the simplest combinations of dots and dashes stand for the most used letters, as this would increase the speed of sending. He began to figure out for himself the frequency with which the various letters occur in the English language. Then he thought of the combination of types in a type-case, and, going to a local newspaper office, found the result all worked out for him. In each case of type such common letters as _e_ and _t_ have many more types than little used letters such as _q_ and _z_. By observing the number of types of each letter provided, Vail was enabled to arrange them in the order of their importance in assigning them symbols in the code. Thus the Morse code was arranged as it stands to-day. Alfred Vail played a very important part in the arrangement of the code as well as in the construction of the apparatus, and there are many who believe that the code should have been called the Vail code instead of the Morse code. [Illustration: MORSE'S FIRST TELEGRAPH INSTRUMENT A pen was attached to the pendulum and drawn across the strip of paper by the action of the electro-magnet. The lead type shown in the lower right-hand corner was used in making electrical contact when sending a message. The modern instrument shown in the lower left-hand corner is the one that sent a message around the world in 1896.] Morse came down to Speedwell when he could to assist Vail with the work, and yet it progressed slowly. But at last, early in January of 1838 they had the telegraph at work, and William Baxter, the apprentice boy, was sent to call the senior Vail. Within a few moments he was in the work-room studying the apparatus. Alfred Vail was at the sending key, and Morse was at the receiver. The father wrote on a piece of paper these words: "A patient waiter is no loser." Handing it to his son, he stated that if he could transmit the message to Morse by the telegraph he would be convinced. The message was sent and recorded and instantly read by Morse. The first test had been completed successfully. VI "WHAT HATH GOD WROUGHT?" Congress Becomes Interested--Washington to Baltimore Line Proposed--Failure to Secure Foreign Patents--Later Indifference of Congress--Lean Years--Success at Last--The Line is Built--The First Public Message--Popularity. Morse and his associates now had a telegraph which they were confident would prove a genuine success. But the great work of introducing this new wonder to the public, of overcoming indifference and skepticism, of securing financial support sufficient to erect a real line, still remained to be done. We shall see that this burden remained very largely upon Morse himself. Had Morse not been a forceful and able man of affairs as well as an inventor, the introduction of the telegraph might have been even longer delayed. The new telegraph was exhibited in New York and Philadelphia without arousing popular appreciation. It was viewed as a scientific toy; few saw in it practical possibilities. Morse then took it to Washington and set up his instruments in the room of the Committee on Commerce of the House of Representatives in the Capitol. Here, as in earlier exhibitions, a majority of those who saw the apparatus in operation remained unconvinced of its ability to serve mankind. But Morse finally made a convert of the Hon. Francis O.J. Smith, chairman of the Committee on Commerce. Smith had previously been in correspondence with the inventor, and Morse had explained to him at length his belief that the Government should own the telegraph and control and operate it for the public good. He believed that the Government should be sufficiently interested to provide funds for an experimental line a hundred miles long. In return he was willing to promise the Government the first rights to purchase the invention at a reasonable price. Later he changed his request to a line of fifty miles, and estimated the cost of erection at $26,000. Smith aided in educating the other members of his committee, and one day in February of 1838 he secured the attendance of the entire body at a test of the telegraph over ten miles of wire. The demonstration convinced them, and many were their expressions of wonder and amazement. One member remarked, "Time and space are now annihilated." As a result the committee reported a bill appropriating $30,000 for the erection of an experimental line between Washington and Baltimore. Smith's report was most enthusiastic in his praise of the invention. In fact, the Congressman became so much interested that he sought a share in the enterprise, and, securing it, resigned from Congress that he might devote his efforts to securing the passage of the bill and to acting as legal adviser. At this time the enterprise was divided into sixteen shares: Morse held nine; Smith, four; Alfred Vail, two; and Professor Gale, one. We see that Morse was a good enough business man to retain the control. Wheatstone and others were developing their telegraphs in Europe, and Morse felt that it was high time to endeavor to secure foreign patents on his invention. Accompanied by Smith, he sailed for England in May, taking with him a new instrument provided by Vail. Arriving in London, they made application for a patent. They were opposed by Wheatstone and his associates, and could not secure even a hearing from the patent authorities. Morse strenuously insisted that his telegraph was radically different from Wheatstone's, laying especial emphasis on the fact that his recording instrument printed the message in permanent form, while Wheatstone's did not. Morse always placed great emphasis on the recording features of his apparatus, yet these features were destined to be discarded in America when his telegraph at last came into use. With no recourse open to him but an appeal to Parliament, a long and expensive proceeding with little apparent possibility of success, Morse went to France, hoping for a more favorable reception. He found the French cordial and appreciative. French experts watched his tests and examined his apparatus, pronouncing his telegraph the best of all that had been devised. He received a patent, only to learn that to be effective the invention must be put in operation in France within two years, under the French patent law. Morse sought to establish his line in connection with a railway, as Wheatstone had established his in England, but was told that the telegraph must be a Government monopoly, and that no private parties could construct or operate. The Government would not act, and Morse found himself again defeated. Faring no better with other European governments, Morse decided to return to America to push the bill for an appropriation before Congress. While Morse was in Europe gaining publicity for the telegraph, but no patents, his former fellow-passenger on the _Sully_, Dr. Charles Jackson, had laid claim to a share in the invention. He insisted that the idea had been his and that he had given it to Morse on the trip across the Atlantic. This Morse indignantly denied. Congress would now take no action upon the invention. A heated political campaign was in progress, and no interest could be aroused in an invention, no matter what were its possibilities in the advancement of the work and development of the nation. Smith was in politics, the Vails were suffering from a financial depression, Professor Gale was a man of very limited means, and so Morse found himself without funds or support. In Paris he had met M. Daguerre, who had just discovered photography. Morse had learned the process and, in connection with Doctor Draper, he fitted up a studio on the roof of the university. Here they took the first daguerreotypes made in America. Morse's work in art had been so much interrupted that he had but few pupils. The fees that these brought to him were small and irregular, and he was brought to the very verge of starvation. We are told of the call Morse made upon one pupil whose tuition was overdue because of a delay in the arrival of funds from his home. "Well, my boy," said the professor, "how are we off for money?" The student explained the situation, adding that he hoped to have the money the following week. "Next week!" exclaimed Morse. "I shall be dead by next week--dead of starvation." "Would ten dollars be of any service?" asked the student, astonished and distressed. "Ten dollars would save my life," was Morse's reply. The student paid the money--all he had--and they dined together, Morse remarking that it was his first meal for twenty-four hours. Morse's situation and feelings at this time are also illustrated by a letter he wrote to Smith late in 1841. I find myself [he wrote] without sympathy or help from any who are associated with me, whose interests, one would think, would impell them to at least inquire if they could render me some assistance. For nearly two years past I have devoted all my time and scanty means, living on a mere pittance, denying myself all pleasures and even necessary food, that I might have a sum, to put my telegraph into such a position before Congress as to insure success to the common enterprise. I am crushed for want of means, and means of so trifling a character, too, that they who know how to ask (which I do not) could obtain in a few hours.... As it is, although everything is favorable, although I have no competition and no opposition--on the contrary, although every member of Congress, so far as I can learn, is favorable--yet I fear all will fail because I am too poor to risk the trifling expense which my journey and residence in Washington will occasion me. I will not run in debt, if I lose the whole matter. No one can tell the days and months of anxiety and labor I have had in perfecting my telegraphic apparatus. For want of means I have been compelled to make with my own hands (and to labor for weeks) a piece of mechanism which could be made much better, and in a tenth the time, by a good mechanician, thus wasting time--time which I cannot recall and which seems double-winged to me. "Hope deferred maketh the heart sick." It is true, and I have known the full meaning of it. Nothing but the consciousness that I have an invention which is to mark an era in human civilization, and which is to contribute to the happiness of millions, would have sustained me through so many and such lengthened trials of patience in perfecting it. A patent on the telegraph had been issued to Morse in 1840. The issuance had been delayed at Morse's request, as he desired to first secure foreign patents, his own American rights being protected by the caveat he had filed. Although the commercial possibilities, and hence the money value of the telegraph had not been established, Morse was already troubled with the rival claims of those who sought to secure a share in his invention. While working and waiting and saving, Morse conceived the idea of laying telegraph wires beneath the water. He prepared a wire by wrapping it in hemp soaked in tar, and then covering the whole with rubber. Choosing a moonlight night in the fall of 1842, he submerged his cable in New York Harbor between Castle Garden and Governors Island. A few signals were transmitted and then the wire was carried away by a dragging anchor. Truly, misfortune seemed to dog Morse's footsteps. This seems to have been the first submarine cable, and in writing of it not long after Morse hazarded the then astonishing prediction that Europe and America would be linked by telegraphic cable. Failing to secure effective aid from his associates, Morse hung on grimly, fighting alone, and putting all of his strength and energy into the task of establishing an experimental line. It was during these years that he demonstrated his greatness to the full. His letters to the members of the Congressional Committee on Commerce show marked ability. They outline the practical possibilities very clearly. Morse realized not only the financial possibilities of his invention, but its benefit to humanity as well. He also presented very practical estimates of the cost of establishing the line under consideration. The committee again recommended that $30,000 be appropriated for the construction of a Washington-Baltimore line. The politicians had come to look upon Morse as a crank, and it was extremely difficult for his adherents to secure favorable action in the House. Many a Congressman compared Morse and his experiments to mesmerism and similar "isms," and insisted that if the Government gave funds for this experiment it would be called upon to supply funds for senseless trials of weird schemes. The bill finally passed the House by the narrow margin of six votes, the vote being taken orally because so many Congressmen feared to go on record as favoring an appropriation for such a purpose. The bill had still to pass the Senate, and here there seemed little hope. Morse, who had come to Washington to press his plan, anxiously waited in the galleries. The bill came up for consideration late one evening just before the adjournment. A Senator who noticed Morse went up to him and said: "There is no use in your staying here. The Senate is not in sympathy with your project. I advise you to give it up, return home, and think no more about it." The inventor went back to his room, with how heavy a heart we may well imagine. He paid his board bill, and found himself with but thirty-seven cents in the world. After many moments of earnest prayer he retired. Early next morning there came to him Miss Annie Ellsworth, daughter of his friend the Commissioner of Patents, and said, "Professor, I have come to congratulate you." "Congratulate me!" replied Morse. "On what?" "Why," she exclaimed, "on the passage of your bill by the Senate!" The bill had been passed without debate in the closing moments of the session. As Morse afterward stated, this was the turning-point in the history of the telegraph. His resources were reduced to the minimum, and there was little likelihood that he would have again been able to bring the matter to the attention of Congress. So pleased was Morse over the news of the appropriation, and so grateful to Miss Ellsworth for her interest in bringing him the good news, that he promised her that she should send the first message when the line was complete. With the Government appropriation at his disposal, Morse immediately set to work upon the Washington-Baltimore line. Professors Gale and Fisher served as his assistants, and Mr. Vail was in direct charge of the construction work. Another person active in the enterprise was Ezra Cornell, who was later to found Cornell University. Cornell had invented a machine for laying wires underground in a pipe. It was originally planned to place the wires underground, as this was thought necessary or their protection. After running the line some five miles out from Baltimore it was found that this method of installing the line was to be a failure. The insulation was not adequate, and the line could not be operated to the first relay station. A large portion of the $30,000 voted by Congress had been spent and the line was still far from completion. Disaster seemed imminent. Smith lost all faith in the enterprise, demanded most of the remaining money under a contract he had taken to lay the line, and a quarrel broke out between him and Morse which further jeopardized the undertaking. Morse and such of his lieutenants as remained faithful in this hour of trial, after a long consultation, decided to string the wire on poles. The method of attaching the wire to the poles was yet to be determined. They finally decided to simply bore a hole through each pole near the top and push the wire through it. Stringing the wire in such fashion was no small task, but it was finally accomplished. It was later found necessary to insulate the wire with bottle necks where it passed through the poles. On May 23, 1844, the line was complete. Remembering his promise to Miss Ellsworth, Morse called upon her next morning to give him the first message. She chose, "What hath God wrought?" and early on the morning of the 24th Morse sat at the transmitter in the Supreme Court room in the Capitol and telegraphed these immortal words to Vail at Baltimore. The message was received without difficulty and repeated back to Morse at Washington. The magnetic telegraph was a reality. Still the general public remained unconvinced. As in the case of Wheatstone's needle telegraph a dramatic incident was needed to demonstrate the utility of this new servant. Fortunately for Morse, the telegraph's opportunity came quickly. The Democratic national convention was in session at Baltimore. After an exciting struggle they dropped Van Buren, then President, and nominated James K. Polk. Silas Wright was named for the Vice-Presidency. At that time Mr. Wright was in Washington. Hearing of the nomination, Alfred Vail telegraphed it to Morse in Washington. Morse communicated with Wright, who stated that he could not accept the honor. The telegraph was ready to carry his message declining the nomination, and within a very few minutes Vail had presented it to the convention at Baltimore, to the intense surprise of the delegates there assembled. They refused to believe that Wright had been communicated with, and sent a committee to Washington to see Wright and make inquiries. They found that the message was genuine, and the utility of the telegraph had been strikingly established. VII DEVELOPMENT OF THE TELEGRAPH SYSTEM The Magnetic Telegraph Company--The Western Union--Crossing the Continent--The Improvements of Alfred Vail--Honors Awarded to Morse--Duplex Telegraphy--Edison's Improvements. For some time the telegraph line between Washington and Baltimore remained on exhibition as a curiosity, no charge being made for demonstrating it. Congress made an appropriation to keep the line in operation, Vail acting as operator at the Washington end. On April 1, 1845, the line was put in operation on a commercial basis, service being offered to the public at the rate of one cent for four characters. It was operated as a branch of the Post-office Department. On the 4th of April a visitor from Virginia came into the Washington office wishing to see a demonstration. Up to this time not a paid message had been sent. The visitor, having no permit from the Postmaster-General, was told that he could only see the telegraph in operation by sending a message. One cent being all the money he had other than twenty-dollar bills, he asked for one cent's worth. The Washington operator asked of Baltimore, "What time is it?" which in the code required but one character. The reply came, "One o'clock," another single character. Thus but two characters had been used, or one-half cent's worth of telegraphy. The visitor expressed himself as satisfied, and waived the "change." This penny was the line's first earnings. Under the terms of the agreement by which Congress had made the appropriation for the experimental line, Morse was bound to give the Government the first right to purchase his invention. He accordingly offered it to the United States for the sum of $100,000. There followed a distressing example of official stupidity and lack of foresight. With the opportunity to own and control the nation's telegraph lines before it the Government declined the offer. This action was taken at the recommendation of the Hon. Cave Johnson, then Postmaster-General, under whose direction the line had been operated. He had been a member of Congress at the time the original appropriation was voted, and had ridiculed the project. The nation was now so unfortunate as to have him as its Postmaster-General, and he reported "that the operation of the telegraph between Washington and Baltimore had not satisfied him that, under any rate of postage that could be adopted, its revenues could be made equal to its expenditures." And yet the telegraph, here offered to the Government for $100,000, was developed under private management until it paid a profit on a capitalization of $100,000,000. Morse seems to have had a really patriotic motive, as well as a desire for immediate return and the freedom from further worries, in his offer to the Government. He was greatly disappointed at its refusal to purchase, a refusal that was destined to make Morse a wealthy man. Amos Kendall, who had been Postmaster-General under Jackson, was now acting as Morse's agent, and they decided to depend upon private capital. Plans were made for a line between New York and Philadelphia, and to arouse interest and secure capital the apparatus was exhibited in New York City at a charge of twenty-five cents a head. The public refused to patronize in sufficient numbers to even pay expenses, and the entire exhibition was so shabby, and the exhibitors so poverty-stricken, that the sleek capitalists who came departed without investing. Some of the exhibitors slept on chairs or on the floor in the bare room, and it is related that the man who was later to give his name and a share of his fortune to Cornell University was overjoyed at finding a quarter on the sidewalk, as it enabled him to buy a hearty breakfast. Though men of larger means refused to take shares, some in humbler circumstances could recognize the great idea and the wonderful vision which Morse had struggled so long to establish--a vision of a nation linked together by telegraphy. The Magnetic Telegraph Company was formed and work started on the line. In August of 1845 Morse sailed for Europe in an endeavor to enlist foreign capital. The investors of Europe proved no keener than those of America, and the inventor returned without funds, but imbued with increased patriotism. He had become convinced that the telegraph could and would succeed on American capital alone. In the next year a line was constructed from Philadelphia to Washington, thus extending the New York-Philadelphia line to the capital. Henry O'Reilly, of Rochester, New York, took an active part in this construction work and now took the contract to construct a line from Philadelphia to St. Louis. This line was finished by December of 1847. The path having been blazed, others sought to establish lines of their own without regard to Morse's patents. One of these was O Reilly, who, on the completion of the line to St. Louis, began one to Now Orleans, without authority from Morse or his company. O'Reilly called his telegraph "The People's Line," and when called to account in the courts insisted not only that his instruments were different from Morse's, and so no infringement of his patents, but also that the Morse system was a harmful monopoly and that "The People's Line" should be encouraged. It was further urged that Wheatstone in England and Steinheil in Germany had invented telegraphs before Morse, and that Professor Henry had invented the relay which made it possible to operate the telegraph over long distances. The suits resulted in a legal victory for Morse, and his patents were maintained. But still other rival companies built lines, using various forms of apparatus, and though the courts repeatedly upheld Morse's patent rights, the pirating was not effectively checked. The telegraph had come to be a necessity and the original company lacked the capital to construct lines with sufficient rapidity to meet the need. Within ten years after the first line had been put into operation the more thickly settled portions of the United States were served by scores of telegraph lines owned by a dozen different companies. Hardly any of these were making any money, though the service was poor and the rates were high. They were all operating on too small a scale and business uses of the telegraph had not yet developed sufficiently. An amalgamation of the scattered, competing lines was needed, both to secure better service for the public and proper dividends for the investors. This amalgamation was effected by Mr. Hiram Sibley, who organized the Western Union in 1856. The plan was ridiculed at the time, some one stating that "The Western Union seems very like collecting all the paupers in the State and arranging them into a union so as to make rich men of them." But these pauper companies did become rich once they were united under efficient management. The nation was just then stretching herself across to the Pacific. The commercial importance of California was growing rapidly. By 1857 stage-coaches were crossing the plains and the pony-express riders were carrying the mail. The pioneers of the telegraph felt that a line should span the continent. This was then a tremendous undertaking, and when Mr. Sibley proposed that the Western Union should undertake the construction of such a line he was met with the strongest opposition. The explorations of Frémont were not far in the past, and the vast extent of country west of the Mississippi was regarded as a wilderness peopled with savages and almost impossible of development. But Sibley had faith; he was possessed of Morse's vision and Morse's courage. The Western Union refusing to undertake the enterprise, he began it himself. The Government, realizing the military and administrative value of a telegraph line to California, subsidized the work. Additional funds were raised and a route selected was through Omaha and Salt Lake City to San Francisco. The undertaking proved less formidable than had been anticipated, for, instead of two years, less than five months were occupied in completing the line. Sibley's tact and ability did much to avoid opposition by the Indians. He made the red men his friends and impressed upon them the wonder of the telegraph. When the line was in operation between Fort Kearney and Fort Laramie he invited the chief of the Arapahoes at Fort Kearney to communicate by telegraph with his friend the chief of the Sioux at Fort Laramie. The two chiefs exchanged telegrams and were deeply impressed. They were told that the telegraph was the voice of the Manitou or Great Spirit. To convince them it was suggested that they meet half-way and compare their experiences. Though they were five hundred miles apart, they started out on horseback, and on meeting each other found that the line had carried their words truly. The story spread among the tribes, and so the telegraph line became almost sacred to the Indians. They might raid the stations and kill the operators, but they seldom molested the wires. Among many ignorant peoples the establishment of the telegraph has been attained with no small difficulty. The Chinese showed a dread of the telegraph, frequently breaking down the early lines because they believed that they would take away the good luck of their district. The Arabs, on the other hand, did not oppose the telegraph. This is partly because the name is one which they can understand, _tel_ meaning wire to them, and _araph_, to know. Thus in Arabic _tele-agraph_ means to know by wire. Just as the Indians of our own plains had difficulty in understanding the telegraph, so the primitive peoples in other parts of the world could scarce believe it possible. A story is told of the construction of an early line in British India. The natives inquired the purpose of the wire from the head man. "The wire is to carry messages to Calcutta," he replied. "But how can words run along a wire?" they asked. The head man puzzled for a moment. "If there were a dog," he replied, "with a tail long enough to reach from here to Calcutta, and you pinched his tail here, wouldn't he howl in Calcutta?" Once Sibley and the other American telegraph pioneers had spanned the continent, they began plans for spanning the globe. Their idea was to unite America and Europe by a line stretched through British Columbia, Alaska, the Aleutian Islands, and Siberia. Siberia had been connected with European Russia, and thus practically the entire line could be stretched on land, only short submarine cables being necessary. It was then seriously doubted that cables long enough to cross the Atlantic were practicable. The expedition started in 1865, a fleet of thirty vessels carrying the men and supplies. Tremendous difficulties had been overcome and a considerable part of the work accomplished when the successful completion of the Atlantic cable made the work useless. Nearly three million dollars had been expended by the Western Union in this attempt. Yet, despite this loss, its affairs were so generally successful and the need for the telegraph so real that it continued to thrive until it reached its present remarkable development. While the line-builders were busy stretching telegraph wires into almost every city and town in the nation, others were perfecting the apparatus. Alfred Vail was a leading figure in this work. Already he had played a large part in designing and constructing the apparatus to carry out Morse's ideas, and he continued to improve and perfect until practically nothing remained of Morse's original apparatus. The original Morse transmitter had consisted of a porte-rule and movable type. This was cumbersome, and Vail substituted a simple key to make and break the circuit. Vail had also constructed the apparatus to emboss the message upon the moving strip of paper, but this he now improved upon. The receiving apparatus was simplified and the pen was replaced by a disk smeared with ink which marked the dots and dashes upon the paper. As we have noticed, Morse took particular pride in the fact that the receiving apparatus in his telegraph was self-recording, and considered this as one of the most important parts of his system. But when the telegraph began to come into commercial use the operators at the receiving end noticed that they could read the messages from the long and short periods between the clicks of the receiving mechanism. Thus they were taking the message by ear and the recording mechanism was superfluous. Rules and fines failed to break them of the habit, and Vail, recognizing the utility of the development, constructed a receiver which had no recording device, but from which the messages were read by listening to the clicks as the armature struck against the frame in which it was set. Thus the telegraph returned in its elements to the form of Professor Henry's original bell telegraph. With his bell telegraph and his relay Henry had the elements of a successful system. He failed, however, to develop them practically or to introduce them to the attention of the public. He was the man of science rather than the practical inventor. Alfred Vail, joining with Morse after the latter had conceived the telegraph, but before his apparatus was in practical form, was a tireless and invaluable mechanical assistant. His inventions of apparatus were of the utmost practical value, and he played a very large part in bringing the telegraph to a form where it could serve man effectively. After success had been won Morse did not extend to Vail the credit which it seems was his due. Yet, though Morse made free use of the ideas and assistance of others, he was richly deserving of a major portion of the fame and the rewards that came to him as inventor of the telegraph. Morse was the directing genius; he contributed the idea and the leadership, and bore the brunt of the burdens when all was most discouraging. Honors were heaped upon Morse both at home and abroad as his telegraph established itself in all parts of the world. Orders of knighthood, medals, and decorations were conferred upon him. Though he had failed to secure foreign patents, many of the foreign governments recognized the value of his invention, and France, Austria, Belgium, Netherlands, Russia, Sweden, Turkey, and some smaller nations joined in paying him a testimonial of four hundred thousand francs. It is to be noticed that Great Britain did not join in this testimonial, though Morse's system had been adopted there in preference to the one developed by Wheatstone. In 1871 a statue of Morse was erected in Central Park, New York City. It was in the spring of the next year that another statue was unveiled, this time one of Benjamin Franklin, and Morse presided at the ceremonies. The venerable man received a tremendous ovation on this occasion, but the cold of the day proved too great a strain upon him. He contracted a cold which eventually resulted in his death on April 2, 1872. While extended consideration cannot be given here to the telegraphic inventions of Thomas A. Edison, no discussion of the telegraph should close without at least some mention of his work in this field. Edison started his career as a telegrapher, and his first inventions were improvements in the telegraph. His more recent and more wonderful inventions have thrown his telegraphic inventions into the shadow. On the telegraph as invented by Morse but one message could be sent over a single wire at one time. It was later discovered that two messages' could be sent over the single wire in opposite directions at the same time. This was called duplex telegraphy. Edison invented duplex telegraphy by which two messages could be sent over the same wire in the same direction at the same time. Later he succeeded in combining the two, which resulted in the quadruplex, by which four messages may be sent over one wire at one time. Though Edison received comparatively little for this invention, its commercial value may be estimated from the statement by the president of the Western Union that it saved that company half a million dollars in a single year. Edison's quadruplex system was also adopted by the British lines. Before this he had perfected an automatic telegraph, work on which had been begun by George Little, an Englishman. Little could make the apparatus effective only over a short line and attained no very great speed. Edison improved the apparatus until it transmitted thirty-five hundred words a minute between New York and Philadelphia. Such is the perfection to which Morse's marvel has been brought in the hands of the most able of modern inventors. VIII TELEGRAPHING BENEATH THE SEA Early Efforts at Underwater Telegraphy--Cable Construction and Experimentation--The First Cables--The Atlantic Cable Projected--Cyrus W. Field Becomes Interested--Organizes Atlantic Telegraph Company--Professor Thomson as Scientific Adviser--His Early Life and Attainments. The idea of laying telegraph wires beneath the sea was discussed long before a practical telegraph for use on land had been attained. It is recorded that a Spaniard suggested submarine telegraphy in 1795. Experiments were conducted early in the nineteenth century with various materials in an effort to find a covering for the wires which would be both a non-conductor of electricity and impervious to water. An employee of the East India Company made an effort to lay a cable across the river Hugli as early as 1838. His method was to coat the wire with pitch inclose it in split rattan, and then wrap the whole with tarred yarn. Wheatstone discussed a Calais-Dover cable in 1840, but it remained for Morse to actually lay an experimental cable. We have already heard of his experiments in New York Harbor in 1842. His insulation was tarred hemp and India rubber. Wheatstone performed a similar experiment in the Bay of Swansea a few months later. Perhaps the first practical submarine cable was laid by Ezra Cornell, one of Morse's associates, in 1845. He laid twelve miles of cable in the Hudson River, connecting Fort Lee with New York City. The cable consisted of two cotton-covered wires inclosed in rubber, and the whole incased in a lead pipe. This cable was in use for several months until it was carried away by the ice in the winter of 1846. These early experimenters found the greatest difficulty in incasing their wires in rubber, practical methods of working that substance being then unknown. The discovery of gutta-percha by a Scotch surveyor of the East India Company in 1842, and the invention of a machine for applying it to a wire, by Dr. Werner Siemens, proved a great aid to the cable-makers. These gutta-percha-covered wires were used for underground telegraphy both in England and on the Continent. Tests were made with such a cable for submarine work off Dover in 1849, and, proving successful, the first cable across the English Channel was laid the next year by John Watkins Brett. The cable was weighted with pieces of lead fastened on every hundred yards. A few incoherent signals were exchanged and the communication ceased. A Boulogne fisherman had caught the new cable in his trawl, and, raising it, had cut a section away. This he had borne to port as a great treasure, believing the copper to be gold in some new form of deposit. This experience taught the need of greater protection for a cable, and the next year another was laid across the Channel, which was protected by hemp and wire wrappings. This proved successful. In 1852 England and Ireland were joined by cable, and the next year a cable was laid across the North Sea to Holland. The success of these short cables might have promised success in an attempt to cross the Atlantic had not failures in the deep water of the Mediterranean made it seem an impossibility. We have noted that Morse suggested the possibility of uniting Europe and America by cable. The same thought had occurred to others, but the undertaking was so vast and the problems so little understood that for many years none were bold enough to undertake the project. A telegraph from New York to St. John's, Newfoundland, was planned, however, which was to lessen the time of communication between the continents. News brought by boats from England could be landed at St. John's and telegraphed to New York, thus saving two days. F.N. Gisborne secured the concession for such a line in 1852, and began the construction. Cables were required to connect Newfoundland with the continent, and to cross the Gulf of St. Lawrence, but the rest of the line was to be strung through the forests. Before much had been accomplished, Gisborne had run out of funds, and work was suspended. In 1854 Gisborne met Cyrus West Field, of New York, a retired merchant of means. Field became interested in Gisborne's project, and as he examined the globe in his library the thought occurred to him that the line to St. John's was but a start on the way to England. The idea aroused his enthusiasm, and he determined to embark upon the gigantic enterprise. He knew nothing of telegraph cables or of the sea-bottom, and so sought expert information on the subject. One important question was as to the condition of the sea-bottom on which the cable must rest. Lieutenant Berryman of the United States Navy had taken a series of soundings and stated that the sea-bottom between Newfoundland and Ireland was a comparatively level plateau covered with soft ooze, and at a depth of about two thousand fathoms. This seemed to the investigators to have been provided for the especial purpose of receiving a submarine cable, so admirably was it suited to this purpose. Morse was consulted, and assured Field that the project was entirely feasible, and that a submarine cable once laid between the continents could be operated successfully. Field thereupon adopted the plans of Gisborne as the first step in the larger undertaking. In 1855 an attempt was made to lay a cable across the Gulf of St. Lawrence, but a storm arose, and the cable had to be cut to save the ship from which it was being laid. Another attempt was made the following summer with better equipment, and the cable was successfully completed. Other parts of the line had been finished, the telegraph now stretched a thousand miles toward England, and New York was connected with St. John's. Desiring more detailed information of the ocean-bed along the proposed route, Field secured the assistance of the United States and British governments. Lieutenant Berryman, U.S.N., in the _Arctic_, and Lieutenant Dayman, R.N., in the _Cyclops_, made a careful survey. Their soundings revealed a ridge near the Irish coast, but the slope was gradual and the general conditions seemed especially favorable. The preliminary work had been done by an American company with Field at the head and Morse as electrician. Now Field went to England to secure capital sufficient for the larger enterprise. With the assistance of Mr. J.W. Brett he organized the Atlantic Telegraph Company, Field himself supplying a quarter of the capital. Associated with Field and Brett in the leadership of the enterprise was Charles Tiltson Bright, a young Englishman who became engineer for the new company. Besides the enormous engineering difficulties of producing a cable long enough and strong enough, and laying it at the bottom of the Atlantic, there were electrical problems involved far greater than Morse seems to have realized. It had been discovered that the passage of a current through a submarine cable is seriously retarded. The retarding of the current as it passes through the water is a difficulty that does not exist with the land telegraph stretched on poles. Faraday had demonstrated that this retarding was caused by induction between the electricity in the wire and the water about the cable. The passage of the current through the wire induces currents in the water, and these moving in the opposite direction act as a drag on the passage of the message through the wire. What the effect of this phenomenon would be on a cable long enough to cross the Atlantic wan a serious problem that required deep study by the company's engineers. It seemed entirely possible that the messages would move so slowly that the operation of the cable, once it was laid, would not pay. Faraday failed to give any definite information on the subject, but Professor William Thomson worked out the law of retardation accurately and furnished to the cable-builders the accurate information which was required. Doctor Whitehouse, electrician for the Atlantic Company, conducted some experiments of his own and questioned the accuracy of Thomson's statements. Thomson maintained his position so ably, and proved himself so thoroughly a master of the subject that Field and his associates decided to enlist him in the enterprise. This addition to the forces was one of the utmost importance. William Thomson, later to become Lord Kelvin, was probably the ablest scientist of his generation, and was destined to prove his great abilities in his early work with the Atlantic cable. William Thomson was born in Belfast, Ireland, in 1824. His father was a teacher and took an especially keen interest in the affairs of his boys because their mother had died while William was very young. When William was eight years of age his father removed to Glasgow, Scotland, where he had secured the chair of mathematics in Glasgow University. His early education he secured from his father, and this training, coupled with his natural brilliancy, enabled him to develop genuine precocity. At the age of eight he attended his father's university lectures as a visitor, and it is reported that on one occasion he answered his father's questions when all of the class had failed. At the age of ten he entered the university, together with his brother James, who was but two years older. The brothers displayed marked interest in science and invention, eagerly pursued their studies in these branches, and performed many electrical experiments together. [Illustration: CYRUS W. FIELD] [Illustration: WILLIAM THOMSON (LORD KELVIN)] James took the degrees B.A. and M.A. in successive years. Though William also passed the examinations, he did not take the degrees, because he had decided to go to Cambridge, and it was thought best that he take all his degrees from that great school. In writing to his older brother at this time, William was accustomed to sign himself "B.A.T.A.I.A.P.," which signified "B.A. to all intents and purposes." After finishing their work at Glasgow the boys traveled extensively on the Continent. At seventeen William entered St. Peter's College, Cambridge University, taking courses in advanced mathematics and continuing to distinguish himself. He took an active part in the life of the university, making something of a record us an athlete, winning the silver sculls, and rowing on a 'varsity crew which took the measure of Oxford in the great annual boat-race. He also interested himself in literature and music, but his real passion was science. Already he had written many learned essays on mathematical electricity and was accomplishing valuable research work. On the completion of his work at Cambridge he secured a fellowship which brought him an income of a thousand dollars a year and enabled him to pursue his studies in Paris. When he was but twenty-two years of age he was made professor of natural philosophy at the University of Glasgow. Though young, he proved entirely successful, and wan immensely popular with his students. At that time the university had no experimental laboratory, and Professor Thomson and his pupils performed their experiments in the professor's room and in an abandoned coal-cellar, slowly developing a laboratory for themselves. His development continued until, when at the age of thirty-three he was called upon to assist with the work of laying an Atlantic cable, he was possessed of scientific attainments which made him invaluable among the cable pioneers. IX THE PIONEER ATLANTIC CABLE Making the Cable--The First Attempt at Laying--Another Effort Checked by Storm--The Cable Laid at Last--Messages Cross the Ocean--The Cable Fails--Professor Thomson's Inventions and Discoveries--Their Part in Designing and Constructing an Improved Cable and Apparatus. Field and his business associates were extremely anxious that the cable be laid with all possible speed, and little time was allowed the engineers and electricians for experimentation. The work of building the cable was begun early in 1857 by two English firms. It consisted of seven copper wires covered with gutta-percha and wound with tarred hemp. Over this were wound heavy iron wires to give protection and added strength. The whole weighed about a ton to the mile, and was both strong and flexible. The distance from the west coast of Ireland to Newfoundland being 1,640 nautical miles, it was decided to supply 2,500 miles of cable, an extra length being, of course, necessary to allow for the inequalities at the bottom of the sea, and the possibility of accident. The British and American governments had already provided subsidies, and they now supplied war-ships for use in the work of laying the cable. The _Agamemnon_, one of the largest of England's war-ships, and the _Niagara_, giant of the United States Navy, were to do the actual work of cable-laying, the cable being divided between them. They were accompanied by the United States frigate _Susquehanna_ and the British war-ships _Leopard_ and _Cyclops_. In August of 1857 the fleet assembled on the Irish coast for the start, and the American sailors landed the end of the cable amid great ceremony. The work of cable-laying was begun by the _Niagara_, which steamed slowly away, accompanied by the fleet. The great cable payed out smoothly as the Irish coast was left behind and the frigate increased her speed. The submarine hill with its dangerous slopes was safely passed, and it was felt that the greatest danger was past. The paying-out machinery seemed to be working perfectly. Telegraphic communication was constantly maintained with the shore end. For six days all went well and nearly four hundred miles of cable had been laid. With the cable dropping to the bottom two miles down it was found that it was flowing out at the rate of six miles an hour while the _Niagara_ was steaming but four. It was evident that the cable was being wasted, and to prevent its running out too fast at this great depth the brake controlling the flow of the cable was tightened. The stern of the vessel rising suddenly on a wave, the strain proved too great and the cable parted and was lost. Instant grief swept over the ship and squadron, for the heart of every one was in the great enterprise. It was felt that it would be useless to attempt to grapple the cable at this great depth, and there seemed nothing to do but abandon it and return. The loss of the cable and of a year's time--since another attempt could not be made until the next season--resulted in a total loss to the company of half a million dollars. Public realization of the magnitude of the task had been awakened by the failure of the first expedition and Field found it far from easy to raise additional capital. It was finally accomplished, however, and a new supply of cable was constructed. Professor Thomson had been studying the problems of submarine telegraphy with growing enthusiasm, and had now arrived at the conclusion that the conductivity of the cable depended very largely upon the purity of the copper employed. He accordingly saw to it that in the construction of the new section all the wires were carefully tested and such as did not prove perfect were discarded. In the mean time the engineers were busy improving the paying-out machinery. They designed an automatic brake which would release the cable instantly upon the strain becoming too great. It was thus hoped to avoid a recurrence of the former accident. Chief-Engineer Bright also arranged a trial trip for the purpose of drilling the staff in their various duties. The same vessels were provided to lay the cable on the second attempt and the fleet sailed in June of 1858, this time without celebration or public ceremony. On this occasion the recommendation of Chief-Engineer Bright was followed, and it was arranged that the _Niagara_ and _Agamemnon_ should meet in mid-ocean, there splice the cable together and proceed in opposite directions, laying the cable simultaneously. On this expedition Professor Thomson was to assume the real scientific leadership, Professor Morse, though he retained his position with the company, taking no active part. The ships had not proceeded any great distance before they ran into a terrible gale. The _Agamemnon_ had an especially difficult time of it, her great load of cable overbalancing the ship and threatening to break loose again and again and carry the great vessel and her precious cargo to the bottom. The storm continued for over a week, and when at last it had blown itself out the _Agamemnon_ resembled a wreck and many of her crew had been seriously injured. But the cable had been saved and the expedition was enabled to proceed to the rendezvous. The _Niagara_, a larger ship, had weathered the storm without mishap. The splice was effected on Saturday, the 26th, but before three miles had been laid the cable caught in the paying-out machinery on the _Niagara_ and was broken off. Another splice was made that evening and the ships started again. The two vessels kept in communication with each other by telegraph as they proceeded, and anxious inquiries and many tests marked the progress of the work. When fifty miles were out, the cable parted again at some point between the vessels and they again sought the rendezvous in mid-Atlantic. Sufficient cable still remained and a third start was made. For a few days all went well and some four hundred miles of cable had been laid with success as the messages passing from ship to ship clearly demonstrated. Field, Thomson, and Bright began to believe that their great enterprise was to be crowned with success when the cable broke again, this time about twenty feet astern of the _Agamemnon_. This time there was no apparent reason for the mishap, the cable having parted without warning when under no unusual strain. The vessels returned to Queenstown, and Field and Thomson went to London, where the directors of the company were assembled. Many were in favor of abandoning the enterprise, selling the remaining cable for what it would bring, and saving as much of their investment as possible. But Field and Thomson were not of the sort who are easily discouraged, and they managed to rouse fresh courage in their associates. Yet another attempt was decided upon, and with replenished stores the _Agamemnon_ and _Niagara_ once again proceeded to the rendezvous. The fourth start was made on the 29th of July. On several occasions as the work progressed communication failed, and Professor Thomson on the _Agamemnon_ and the other electricians on the _Niagara_ spent many anxious moments fearing that the line had again been severed. On each occasion, however, the current resumed. It was afterward determined that the difficulties were because of faulty batteries rather than leaks in the cable. On both ships bad spots were found in the cable as it was uncoiled and some quick work was necessary to repair them before they dropped into the sea, since it was practically impossible to stop the flow of the cable without breaking it. The _Niagara_ had some narrow escapes from icebergs, and the _Agamemnon_ had difficulties with ships which passed too close and a whale which swam close to the ship and grazed the precious cable. But this time there was no break and the ships approached their respective destinations with the cable still carrying messages between them. The _Niagara_ reached the Newfoundland coast on August 4th, and early the next morning landed the cable in the cable-house at Trinity Bay. The _Agamemnon_ reached the Irish coast but a few hours later, and her end of the cable was landed on the afternoon of the same day. The public, because of the repeated failures, had come to look upon the cable project as a sort of gigantic wild-goose chase. The news that a cable had at last been laid across the ocean was received with incredulity. Becoming convinced at last, there was great rejoicing in England and America. Queen Victoria sent to President Buchanan a congratulatory message in which she expressed the hope "that the electric cable which now connects Great Britain with the United States will prove an additional link between the two nations, whose friendship is founded upon their mutual interest and reciprocal esteem." The President responded in similar vein, and expressed the hope that the neutrality of the cable might be established. Honors were showered upon the leaders in the enterprise. Charles Bright, the chief engineer, was knighted, though he was then but twenty-six years of age. Banquet after banquet was held in England at which Bright and Thomson were the guests of honor. New York celebrated in similar fashion. A grand salute of one hundred guns was fired, the streets were decorated, and the city was illuminated at night. The festivities rose to the highest pitch in September with Field receiving the plaudits of all New York. Special services were held in Trinity Church, and a great celebration was held in Crystal Palace. The mayor presented to Field a golden casket, and the ceremony was followed by a torchlight parade. That very day the last message went over the wire. The shock to the public was tremendous. Many insisted that the cable had never been operated and that the entire affair was a hoax. This was quickly disproved. Aside from the messages between Queen and President many news messages had gone over the cable and it had proved of great value to the British Government. The Indian mutiny had been in progress and regiments in Canada had received orders by mail to sail for India. News reached England that the mutiny was at an end, and the cable enabled the Government to countermand the orders, thus saving a quarter of a million dollars that would have been expended in transporting the troops. The engineers to whom the operations of the cable had been intrusted had decided that very high voltages were necessary to its successful operation. They had accordingly installed huge induction coils and sent currents of two thousand volts over the line. Even this voltage had failed to operate the Morse instruments, the drag by induction proving too great. The strain of this high voltage had a very serious effect upon the insulation. Abandoning the Morse instruments and the high voltage, recourse was then had to Professor Thomson's instruments, which proved entirely effective with ordinary battery current. Because of the effect of induction the current is much delayed in traveling through a long submarine cable and arrives in waves. Professor Thomson devised his mirror galvanometer to meet this difficulty. This device consists of a large coil of very fine wire, in the center of which, in a small air-chamber, is a tiny mirror. Mounted on the back of the mirror are very small magnets. The mirror is suspended by a fiber of the finest silk. Thus the weakest of currents coming in over the wire serve to deflect the mirror, and a beam of light being directed upon the mirror and reflected by it upon a screen, the slightest movement of the mirror is made visible. If the mirror swings too far its action is deadened by compressing the air in the chamber. The instrument is one of the greatest delicacy. Such was the greatest contribution of Professor Thomson to submarine telegraphy. Without it the cable could not have been operated even for a short period. Had it been used from the first the line would not have been ruined and might have been used for a considerable period. Professor Thomson together with Engineer Bright made a careful investigation of the causes of failure. The professor pointed out that had the mirror galvanometer been used with a moderate current the cable could have been continued in successful operation. Ha continued to improve this apparatus and at the same time busied himself with a recording instrument to be used for cable work. Both Thomson and Bright had recommended a larger and stronger cable, and other failures in cable-laying in the Red Sea and elsewhere in the next few years bore out their contentions. But with each failure new experience was gained and methods were perfected. Professor Thomson continued his work with the utmost diligence and continued to add to the fund of scientific knowledge on the subject. So it was that he was prepared to take his place as scientific leader of the next great effort. X A SUCCESSFUL CABLE ATTAINED Field Raises New Capital--The _Great Eastern_ Secured and Equipped--Staff Organized with Professor Thomson as Scientific Director--Cable Parts and is Lost--Field Perseveres--The Cable Recovered--The Continents Linked at Last--A Commercial Success--Public Jubilation--Modern Cables. The early 'sixties were trying years for the cable pioneers. It required all of Field's splendid genius and energy to keep the project alive. In the face of repeated failures, and doubt as to whether messages could be sent rapidly enough to make any cable a commercial success, it was extremely difficult to raise fresh capital. America continued to evince interest in the cable, but with, the Civil War in progress it was not easy to raise funds. But no discouragement could deter Field. Though he suffered severely from seasickness, he crossed the Atlantic sixty-four times in behalf of the great enterprise which he had begun. It was necessary to raise three million dollars to provide a cable of the improved type decided upon and to install it properly. The English firm of Glass, Eliot & Company, which was to manufacture the cable, took a very large part of the stock. The new cable was designed in accordance with the principles enunciated by Professor Thomson. The conductor consisted of seven wires of pure copper, weighing three hundred pounds to the mile. This copper core was covered with Chatterton's compound, which served as water-proofing. This was surrounded by four layers of gutta-percha, cemented together by the compound, and about this hemp was wound. The outer layer consisted of eighteen steel wires wound spirally, each being covered with a wrapping of hemp impregnated with a preservative solution. The new cable was twice as heavy as the old and more than twice as strong, a great advance having been made in the methods of manufacturing steel wire. It was decided that the cable should, be laid by one vessel, instead of endeavoring to work from two as in the past. Happily, a boat was available which was fitted to carry this enormous burden. This was the _Great Eastern_, a mammoth vessel far in advance of her time. This great ship of 22,500 tons had been completed in 1857, but had not proved a commercial success. The docks of that day were not adequate, the harbors were not deep enough, and the cargoes were insufficient. She had long lain idle when she was secured by the cable company and fitted out for the purpose of laying the cable, which was the first useful work which had been found for the great ship. The 2,300 miles of heavy cable was coiled into the hull and paying-out machinery was installed upon the decks. Huge quantities of coal and other supplies were added. Capt. James Anderson of the Cunard Line was placed in command of the ship for the expedition, with Captain Moriarty, R.N., as navigating officer. Professor Thomson and Mr. C.F. Varley represented the Atlantic Telegraph Company as electricians and scientific advisers. Mr. Samuel Canning was engineer in charge for the contractors. Mr. Field was also on board. It was on July 23, 1865, that the expedition started from the Irish coast, where the eastern end of the cable had been landed. Less than a hundred miles of cable had been laid when the electricians discovered a fault in the cable. The _Great Eastern_ was stopped, the course was retraced, and the cable picked up until the fault was reached. It was found that a piece of iron wire had in some way pierced the cable so that the insulation was ruined. This was repaired and the work of laying was again commenced. Five days later, when some seven hundred miles of cable had been laid, communication was again interrupted, and once again they turned back, laboriously lifting the heavy cable from the depths, searching for the break. Again a wire was found thrust through the cable, and this occasioned no little worry, as it was feared that this was being done maliciously. It was on August 2d that the next fault was discovered. Nearly two-thirds of the cable was now in place and the depth was here over one mile. Raising the cable was particularly difficult, and just at this juncture the _Great Eastern's_ machinery broke down, leaving her without power and at the mercy of the waves. Subjected to an enormous strain, the precious cable parted and was lost. Despite the great depth, efforts were made to grapple the lost cable. Twice the cable was hooked, but on both occasions the rope parted and after days of tedious work the supply of rope was exhausted and it was necessary to return to England. Still another cable expedition had ended in failure. Field, the indomitable, began all over again, raising additional funds for a new start. The _Great Eastern_ had proved entirely satisfactory, and it was hoped that with improvements in the grappling-gear the cable might be recovered. The old company gave way before a new organization known as the Anglo-American Telegraph Company. It was decided to lay an entirely new cable, and then to endeavor to complete the one partially laid in 1865. With no services other than private prayers at the station on the Irish shore, the _Great Eastern_ steamed away for the new effort on July 13, 1866. This time the principal difficulties arose within the ship. Twice the cable became tangled in the tanks and it was necessary to stop the ship while the mass was straightened out. Most of the time the "coffee-mill," as the seamen called the paying-out machinery, ground steadily away and the cable sank into the sea. As the work progressed Field and Thomson, who had suffered so many failures in their great enterprise, watched with increasing anxiety. They were almost afraid to hope that the good fortune would continue. Just two weeks after the Irish coast had been left behind the _Great Eastern_ approached Newfoundland just as the shadows of night were added to those of a thick fog. On the next morning, July 28th, she steamed into Trinity Bay, where flags were flying in the little town in honor of the great accomplishment. Amid salutes and cheers the cable was landed and communication between the continents was established. Almost the first news that came over the wire was that of the signing of the treaty of peace which ended the war between Prussia and Austria. Early in August the _Great Eastern_ again steamed away to search for the cable broken the year before. Arriving on the spot, the grapples were thrown out and the tedious work of dragging the sea-bottom was begun. After many efforts the cable was finally secured and raised to the surface. A new section was spliced on and the ship again turned toward America. On September 7th the second cable was successfully landed, and two wires were now in operation between the continents. Thus was the great task doubly fulfilled. Once again there were public celebrations in England and America. Field received the deserved plaudits of his countrymen and Thomson was knighted in recognition of his achievements. [Illustration: THE "GREAT EASTERN" LAYING THE ATLANTIC CABLE. 1866] The new cables proved a success and were kept in operation for many years. Thomson's mirror receiver had been improved until it displayed remarkable sensitiveness. Using the current from a battery placed in a lady's thimble, a message was sent across the Atlantic through one cable and back through the other. Professor Thomson was to give to submarine telegraphy an even more remarkable instrument. The mirror instrument did not give a permanent record of the messages. The problem of devising a means of recording the messages delicate enough so that it could be operated with rapidity by the faint currents coming over a long cable was extremely difficult. But Thomson solved it with his siphon recorder. In this a small coil is suspended between the poles of a large magnet; the coil being free to turn upon its axis. When the current from the cable passes through the coil it moves, and so varies the position of the ink-siphon which is attached to it. The friction of a pen on paper would have proved too great a drag on so delicate an instrument, and so a tiny jet of ink from the siphon was substituted. The ink is made to pass through the siphon with sufficient force to mark down the message by a delightfully ingenious method. Thomson simply arranged to electrify the ink, and it rushes through the tiny opening on to the paper just as lightning leaps from cloud to earth. Professor, now Sir, Thomson continued to take an active part in the work of designing and laying new cables. Not only did he contribute the apparatus and the scientific information which made cables possible, but he attained renown as a physicist and a scientist in many other fields. In 1892 he was given the title of Lord Kelvin, and it was by this name that he was known as the leading physicist of his day. He survived until 1907. To Cyrus W. Field must be assigned a very large share of the credit for the establishment of telegraphic communication between the continents. He gave his fortune and all of his tremendous energy and ability to the enterprise and kept it alive through failure after failure. He was a promoter of the highest type, the business man who recognized a great human need and a great opportunity for service. Without his efforts the scientific discoveries of Thomson could scarcely have been put to practical use. The success of the first cable inspired others. In 1869 a cable from France to the United States was laid from the _Great Eastern_. In 1875 the Direct United States Cable Company laid another cable to England, which was followed by another cable to France. One cable after another was laid until there are now a score. This second great development in communication served to bring the two continents much closer together in business and in thought and has proved of untold benefit. XI ALEXANDER GRAHAM BELL, THE YOUTH The Family's Interest in Speech Improvement--Early Life-Influence of Sir Charles Wheatstone--He Comes to America--Visible Speech and the Mohawks--The Boston School for Deaf Mutes--The Personality of Bell. The men of the Bell family, for three generations, have interested themselves in human speech. The grandfather, the father, and the uncle of Alexander Graham Bell were all elocutionists of note. The grandfather achieved fame in London; the uncle, in Dublin; and the father, in Edinburgh. The father applied himself particularly to devising means of instructing the deaf in speech. His book on _Visible Speech_ explained his method of instructing deaf mutes in speech by the aid of their sight, and of teaching them to understand the speech of others by watching their lips as the words are spoken. Alexander Graham Bell was born in Edinburgh in 1847, and received his early education in the schools of that city. He later studied at Warzburg, Germany, where he received the degree of Doctor of Philosophy. He followed very naturally in the footsteps of his father, taking an early interest in the study of speech. He was especially anxious to aid his mother, who was deaf. As a boy he exhibited a genius for invention, as well as for acoustics. Much of this was duo to the wise encouragement of his father. He himself has told of a boyhood invention. My father once asked my brother Melville and myself to try to make a speaking-machine, I don't suppose he thought we could produce anything of value, in itself. But he knew we could not even experiment and manufacture anything which even tried to speak, without learning something of the voice and the throat; and the mouth--all that wonderful mechanism of sound production in which he was so interested. So my brother and I went to work. We divided the task--he was to make the lungs and the vocal cords, I was to make the mouth and the tongue. He made a bellows for the lungs and a very good vocal apparatus out of rubber. I procured a skull and molded a tongue with rubber stuffed with cotton wool, and supplied the soft parts of the throat with the same material Then I arranged joints, so the jaw and the tongue could move. It was a great day for us when we fitted the two parts of the device together. Did it speak? It squeaked and squawked a good deal, but it made a very passable imitation of "Mam-ma--Mam-ma." It sounded very much like a baby. My father wanted us to go on and try to get other sounds, but we were so interested in what we had done we wanted to try it out. So we proceeded to use it to make people think there was a baby in the house, and when we made it cry "Mam-ma," and heard doors opening and people coming, we were quite happy. What has become of It? Well, that was across the ocean, in Scotland, but I believe the mouth and tongue part that I made is in Georgetown somewhere; I saw it not long ago. The inventor tells of another boyhood invention that, though it had no connection with sound or speech, shows his native ingenuity. Again we will tell it in his own words. I remember my first invention very well. There were several of us boys, and we were fond of playing around a mill where they ground wheat into flour. The miller's son was one of the boys, and I am afraid he showed us how to be a good deal of a nuisance to his father. One day the miller called us into the mill and said, "Why don't you do something useful instead of just playing all the time?" I wasn't afraid of the miller as much as his son was, so I said, "Well, what can we do that is useful?" He took up a handful of wheat, ran it over in his hand and said: "Look at that! If you could manage to get the husks off that wheat, that would be doing something useful!" So I took some wheat home with me and experimented. I found the husks came off without much difficulty. I tried brushing them off and they came off beautifully. Then it occurred to me that brushing was nothing but applying friction to them. If I could brush the husks off, why couldn't the husks be rubbed off? There was in the mill a machine--I don't know what it was for--but it whirled its contents, whatever it was, around in a drum. I thought, "Why wouldn't the husks come off if the raw wheat was whirled around in that drum?" So back I went to the miller and suggested the idea to him. "Why," he said, "that's a good idea." So he called his foreman and they tried it, and the husks came off beautifully, and they've been taking husks off that way ever since. That was my very first invention, and it led me to thinking for myself, and really had quite an influence on my way and methods of thought. Up to his sixteenth year young Bell's reading consisted largely of novels, poetry, and romantic tales of Scotch heroes. But in addition he was picking up some knowledge of anatomy, music, electricity, and telegraphy. When he was but sixteen years of age his father secured for him a position as teacher of elocution and this necessarily turned his thought into more serious channels. He now spent his leisure studying sound. During this period he made several discoveries in sound which were of some small importance. When he was twenty-one years of age he went to London and there had the good fortune to come to the attention of Charles Wheatstone and Alex J. Ellis. Ellis was at that time president of the London Philological Society, and had translated Helmholtz's _The Sensation of Tone_ into English. He had made no little progress with sound, and demonstrated to Bell the methods by which German scientists had caused tuning-forks to vibrate by means of electro-magnets and had combined the tones of several tuning-forks in an effort to reproduce the sound of the human voice. Helmholtz had performed this experiment simply to demonstrate the physical basis of sound, and seems to have had no idea of its possible use in telephony. That an electro-magnet could vibrate a tuning-fork and so produce sound was an entirely new and fascinating idea to the youth. It appealed to his imagination, quickened by his knowledge of speech. "Why not an electrical telegraph?" he asked himself. His idea seems to have been that the electric current could carry different notes over the wire and reproduce them by means of the electro-magnet. Although Bell did not know it, many others were struggling with the same problem, the answer to which proved most elusive. It gave Bell a starting-point, and the search for the telephone began. Sir Charles Wheatstone was then England's leading man of science, and so Bell sought his counsel. Wheatstone received the young man and listened to his statement of his ideas and ambitions and gave him every encouragement. He showed him a talking-machine which had recently been invented by Baron de Kempelin, and gave him the opportunity to study it closely. Thus Bell, the eager student, the unknown youth of twenty-two, came under the influence of Wheatstone, the famous scientist and inventor of sixty-seven. This influence played a great part in shaping Bell's career, arousing as it did his passion for science. This decided him to devote himself to the problem of reproducing sounds by mechanical means. Thus a new improvement in the means of human communication was being sought and another pioneer of science was at work. The death of the two brothers of the young scientist from tuberculosis, and the physician's report that he himself was threatened by the dread malady, forced a change in his plans and withdrew him from an atmosphere which was so favorable to the development of his great ideas. He was told that he must seek a new climate and lead a more vigorous life in the open. Accompanied by his father, he removed to America and at the age of twenty-six took up the struggle for health in the little Canadian town of Brantford. He occupied himself by teaching his father's system of visible speech among the Mohawk Indians. In this work he met with no little success. At the same time he was gaining in bodily vigor and throwing off the tendency to consumption which had threatened his life. He did not forget the great idea which filled his imagination and eagerly sought the telephone with such crude means as were at hand. He succeeded in designing a piano which, with the aid of the electric current, could transmit its music over a wire and reproduce it. While lecturing in Boston on his system of teaching visible speech, the elder Bell received a request to locate in that city and take up his work in its schools. He declined the offer, but recommended his son as one entirely competent for the position. Alexander Graham Bell received the offer, which he accepted, and he was soon at work teaching the deaf mutes in the school which Boston had opened for those thus afflicted. He met with the greatest success in his work, and ere long achieved a national reputation. During the first year of his work, 1871, he was the sensation of the educational world. Boston University offered him a professorship, in which position he taught others his system of teaching, with increased success. The demand for his services led him to open a School of Vocal Physiology. He had made some improvements in his father's system for teaching the deaf and dumb to speak and to understand spoken words, and displayed great ability as a teacher. His experiments with telegraphy and telephony had been laid aside, and there seemed little chance that he would turn from the work in which he was accomplishing so much for so many sufferers, and which was bringing a comfortable financial return, and again undertake the tedious work in search for a telephone. Fortunately, Bell was to establish close relationships with those who understood and appreciated his abilities and gave him encouragement in his search for a new means of communication. Thomas Sanders, a resident of Salem, had a five-year-old son named Georgie who was a deaf mute. Mr. Sanders sought Bell's tutelage for his son, and it was agreed that Bell should give Georgie private lessons for the sum of three hundred and fifty dollars a year. It was also arranged that Bell was to reside at the Sanders home in Salem. He made arrangements to conduct his future experiments there. Another pupil who came to him about this time was Mabel Hubbard, a fifteen-year-old girl who had lost her hearing and consequently her powers of speech, through an attack of scarlet fever when an infant. She was a gentle and lovable girl, and Bell fell completely in love with his pupil. Four years later he was to marry her and she was to prove a large influence in helping him to success. She took the liveliest interest in all of his experiments and encouraged him to new endeavor after each failure. She kept his records and notes and wrote his letters. Through her Bell secured the support of her father, Gardiner G. Hubbard, who was widely known as one of Boston's ablest lawyers. He was destined to become Bell's chief spokesman and defender. Hubbard first became aware of Bell's inventive genius when the latter was calling one evening at the Hubbard home in Cambridge. Bell was illustrating some mysteries of acoustics with the aid of the piano. "Do you know," he remarked, "that if I sing the note G close to the strings of the piano, the G string will answer me?" This did not impress the lawyer, who asked its significance. "It is a fact of tremendous importance," answered Bell. "It is evidence that we may some day have a musical telegraph which will enable us to send as many messages simultaneously over one wire as there are notes on that piano." From that time forward Hubbard took every occasion to encourage Bell to carry forward his experiments in musical telegraphy. As a young man Bell was tall and slender, with jet-black eyes and hair, the latter being pushed back into a curly tangle. He was sensitive and high-strung, very much the artist and the man of science. His enthusiasms were intense, and, once his mind was filled with an idea, he followed it devotedly. He was very little the practical business man and paid scant attention to the small, practical details of life. He was so interested in visible speech, and so keenly alert to the pathos of the lives of the deaf mutes, that he many times seriously considered giving over all experiments with the musical telegraph and devoting his entire life and energies to the amelioration of their condition. XII THE BIRTH OF THE TELEPHONE The Cellar at Sanderses'--Experimental Beginnings--Magic Revived in Salem Town--The Dead Man's Ear--The Right Path--Trouble and Discouragement--The Trip to Washington--Professor Joseph Henry--The Boston Workshop--The First Faint Twang of the Telephone--Early Development. Alexander Graham Bell had not resided at the Sanderses' home very long before he had fitted the basement up as a workshop. For three years he haunted it, spending all of his leisure time in his experiments. Here he had his apparatus, and the basement was littered with a curious combination of electrical and acoustical devices--magnets, batteries, coils of wire, tuning-forks, speaking-trumpets, etc. Bell had a great horror that his ideas might be stolen and was very nervous over any possible intrusion into his precious workshop. Only the members of the Sanders family were allowed to enter the basement. He was equally cautious in purchasing supplies and equipment lest his very purchases reveal the nature of his experiments. He would go to a half-dozen different stores for as many articles. He usually selected the night for his experiments, and pounded and scraped away indefatigably, oblivious of the fact that the family, as well as himself, was sorely in need of rest. "Bell would often awaken me in the middle of the night," says Mr. Sanders, "his black eyes blazing with excitement. Leaving me to go down to the cellar, he would rush wildly to the barn and begin to send me signals along his experimental wires. If I noticed any improvement in his apparatus he would be delighted. He would leap and whirl around in one of his 'war-dances,' and then go contentedly to bed. But if the experiment was a failure he would go back to his work-bench to try some different plan." In common with other experimenters who were searching for the telephone, Bell was experimenting with a sort of musical telegraph. Eagerly and persistently he sought the means that would replace the telegraph with its cumbersome signals by a new device which would enable the human voice itself to be transmitted. The longer he worked the greater did the difficulties appear. His work with the deaf and dumb was alluring, and on many occasions he seriously considered giving over his other experiments and devoting himself entirely to the instruction of the deaf and dumb and to the development of his system of making speech visible by making the sound-vibrations visible to the eye. But as he mused over the difficulties in enabling a deaf mute to achieve speech nothing else seemed impossible. "If I can make a deaf mute talk," said Bell, "I can make iron talk." One of his early ideas was to install a harp at one end of the wire and a speaking-trumpet at the other. His plan was to transmit the vibrations over the wire and have the voice reproduced by the vibrations of the strings of the harp. By attaching a light pencil or marker to a cord or membrane and causing the latter to vibrate by talking against it, he could secure tracings of the sound-vibrations. Different tracings were secured from different sounds. He thus sought to teach the deaf to speak by sight. At this time Bell enjoyed the friendship of Dr. Clarence J. Blake, an eminent Boston aurist, who suggested that the experiments be conducted with a human ear instead of with a mechanical apparatus in imitation of the ear. Bell eagerly accepted the idea, and Doctor Blake provided him with an ear and connecting organs cut from a dead man's head. Bell soon had the ghastly specimen set up in his workshop. He moistened the drum with glycerine and water and, substituting a stylus of hay for the stapes bone, he obtained a wonderful series of curves which showed the vibrations of the human voice as recorded by the ear. One can scarce imagine a stranger picture than Bell must have presented in the conduct of those experiments. We can almost see him with his face the paler in contrast with his black hair and flashing black eyes as he shouted and whispered by turns into the ghastly ear. Surely he must have looked the madman, and it is perhaps fortunate that he was not observed by impressionable members of the public else they would have been convinced that the witches had again visited old Salem town to ply their magic anew. But it was a new and very real and practical sort of magic which was being worked there. His experiments with the dead man's ear brought to Bell at least one important idea. He noted that, though the ear-drum was thin and light, it was capable of sending vibrations through the heavy bones that lay back of it. And so he thought of using iron disks or membranes to serve the purpose of the drum in the ear and arrange them so that they would vibrate an iron rod. He thought of connecting two such instruments with an electrified wire, one of which would receive the sound-vibrations and the other of which would reproduce them after they had been transmitted along the wire. At last the experimenter was on the right track, with a conception of a practicable method of transmitting sound. He now possessed a theoretical knowledge of what the telephone he sought should be, but there yet remained before him the enormous task of devising and constructing the apparatus which would carry out the idea, and find the best way of utilizing the electrical current for this work. Bell was now at a critical point in his career and was confronted by the same difficulty which assails so many inventors. In his constant efforts to achieve a telephone he had entirely neglected his school of vocal physiology, which was now abandoned. Georgie Sanders and Mabel Hubbard were his only pupils. Though Sanders and Hubbard were genuinely interested in Bell and his work, they felt that he was impractical, and were especially convinced that his experiments with the ear and its imitations were entirely useless. They believed that the electrical telegraph alone presented possibilities, and they told Bell that unless he would devote himself entirely to the improvement of this instrument and cease wasting time and money over ear toys that had no commercial value they would no longer give him financial support. Hubbard went even further, and insisted that if Bell did not abandon his foolish notions he could not marry his daughter. Bell was almost without funds, his closest friends now seemed to turn upon him, and altogether he was in a sorry plight. Of course Sanders and Hubbard meant the best, yet in reality they were seeking to drive their protégé in exactly the wrong direction. As far back as 1860 a German scientist named Philipp Reis produced a musical telephone that even transmitted a few imperfect words. But it would not talk successfully. Others had followed in his footsteps, using the musical telephone to transmit messages with the Morse code by means of long and short hums. Elisha Gray, of Chicago, also experimented with the musical telegraph. At the transmitting end a vibrating steel tongue served to interrupt the electric current which passed over the wire in waves, and, passing through the coils of an electro-magnet at the receiving end, caused another strip of steel located near the magnet to vibrate and so produce a tone which varied with the current. All of these developments depended upon the interruption of the current by some kind of a vibrating contact. The limitations which Sanders and Hubbard sought to impose upon Bell, had they been obeyed to the letter, must have prevented his ultimate success. In a letter to his mother at this time, he said: I am now beginning to realize the cares and anxieties of being an inventor. I have had to put off all pupils and classes, for flesh and blood could not stand much longer such a strain as I have had upon me. But good fortune was destined to come to Bell along with the bad. On an enforced trip to Washington to consult his patent attorney--a trip he could scarce raise funds to make--Bell met Prof. Joseph Henry. We have seen the part which this eminent scientist had played in the development of the telegraph. Now he was destined to aid Bell, as he had aided Morse a generation earlier. The two men spent a day over the apparatus which Bell had with him. Though Professor Henry was fifty years his senior and the leading scientist in America, the youth was able to demonstrate that he had made a real discovery. "You are in possession of the germ of a great invention," said Henry, "and I would advise you to work at it until you have made it complete." "But," replied Bell, "I have not got the electrical knowledge that is necessary." "Get it," was Henry's reply. This proved just the stimulus Bell needed, and he returned to Boston with a new determination to perfect his great idea. Bell was no longer experimenting in the Sanderses' cellar, having rented a room in Boston in which to carry on his work. He had also secured the services of an assistant, one Thomas Watson, who received nine dollars a week for his services in Bell's behalf. The funds for this work were supplied by Sanders and Hubbard jointly, but they insisted that Bell should continue his experiments with the musical telegraph. Though he was convinced that the opportunities lay in the field of telephony, Bell labored faithfully for regular periods with the devices in which his patrons were interested. The remainder of his time and energy he put upon the telephone. The basis of his telephone was still the disk or diaphragm which would vibrate when the sound-waves of the voice were thrown against it. Behind this were mounted various kinds of electro-magnets in series with the electrified wire over which the inventor hoped to send his messages. For three years they labored with this apparatus, trying every conceivable sort of disk. It is easy to pass over those three years, filled as they were with unceasing toil and patient effort, because they were drab years when little of interest occurred. But these were the years when Bell and Watson were "going to school," learning how to apply electricity to this new use, striving to make their apparatus talk. How dreary and trying these years must have been for the experimenters we may well imagine. It requires no slight force of will to hold oneself to such a task in the face of failure after failure. By June of 1875 Bell had completed a new Instrument. In this the diaphragm was a piece of gold-beater's skin, which Bell had selected as most closely resembling the drum in the human ear. This was stretched tight to form a sort of drum, and an armature of magnetized iron was fastened to its middle. Thus the bit of iron was free to vibrate, and opposite it was an electro-magnet through which flowed the current that passed over the line. This acted as the receiver. At the other end of the wire was a sort of crude harmonica with a clock spring, reed, and magnet. Bell and Watson had been working upon their crude apparatus for months, and finally, on June 2d, sounds were actually transmitted. Bell was afire with enthusiasm; the first great step had been taken. The electric current had carried sound-vibrations along the wire and had reproduced them. If this could be done a telephone which would reproduce whole words and sentences could be attained. [Illustration: ALEXANDER GRAHAM BELL] [Illustration: THOMAS A. WATSON] So great was Bell's enthusiasm over this achievement that he succeeded in convincing Sanders and Hubbard that his idea was practical, and they at last agreed to finance him in his further experiments with the telephone. A second membrane receiver was constructed, and for many more weeks the experiments continued. It was found that sounds were carried from instrument to instrument, but as a telephone they were still far from perfection. It was not until March of 1876 that Bell, speaking into the instrument in the workroom, was heard and understood by Watson at the other instrument in the basement. The telephone had carried and delivered an intelligible message. The telephone which Bell had invented, and on which he received a patent on his twenty-ninth birthday, consisted of two instruments similar in principle to what we would now call receivers. If you will experiment with the receiver of a modern telephone you will find that it will transmit as well as receive sound. The heart of the transmitter was an electro-magnet in front of which was a drum-like membrane with a piece of iron cemented to its center opposite the magnet. A mouthpiece was arranged to throw the sounds of the voice against the diaphragm, and as the membrane vibrated the bit of iron upon it--acting as an armature--induced currents corresponding to the sound-waves, in the coils of the electro-magnet. Passing over the line the current entered the coils of the tubular electro-magnet in the receiver. A thin disk of soft iron was fastened at the end of this. When the current-waves passed through the coils of the magnet the iron disk was thrown into vibration, thus producing sound. As it vibrated with the current produced by the iron on the vibrating membrane in the transmitter acting as an armature, transmitter and receiver vibrated in unison and so the same sound was given off by the receiver and made audible to the human ear as was thrown against the membrane of the transmitter by the voice. The patent issued to Bell has been described as "the most valuable single patent ever issued." Certainly it was destined to be of tremendous service to civilization. It was so entirely new and original that Bell found difficulty in finding terms in which to describe his invention to the patent officials. He called it "an improvement on the telegraph," in order that it might be identified as an improvement in transmitting intelligence by electricity. In reality the telephone was very far from being a telegraph or anything in the nature of a telegraph. As Bell himself stated, his success was in large part due to the fact that he had approached the problem from the viewpoint of an expert in sound rather than as an electrician. "Had I known more about electricity and less about sound," he said, "I would never have invented the telephone." As we have seen, those electricians who worked from the viewpoint of the telegraph never got beyond the limitations of the instrument and found that with it they could transmit signals but not sounds. Bell, with his knowledge of the laws of speech and sound, started with the principles of the transmission of sound as a basis and set electricity to carrying the sound-vibrations. XIII THE TELEPHONE AT THE CENTENNIAL Boll's Impromptu Trip to the Exposition--The Table Under the Stairs--Indifference of the Judges--Enter Don Pedro, Emperor of Brazil--Attention and Amazement--Skepticism of the Public--The Aid of Gardiner Hubbard--Publicity Campaign. The Philadelphia Centennial Exposition--America's first great exposition--opened within a month after the completion of the first telephone. The public knew nothing of the telephone, and before it could be made a commercial success and placed in general service the interest of investors and possible users had to be aroused. The Centennial seemed to offer an unusual opportunity to place the telephone before the public. But Bell, like Morse, had no money with which to push his invention. Hubbard was one of the commissioners of the exposition, and exerted his influence sufficiently so that a small table was placed in an odd corner in the Department of Education for the exhibition of the apparatus. The space assigned was a narrow strip between the stairway and the wall. But no provision was made to allow Bell himself to be present. The young inventor was almost entirely without funds. Sanders and Hubbard had paid nothing but his room rent and the cost of his experiments. He had devoted himself to his inventions so entirely that he had lost all of his professional income. So it was that he was forced to face the prospect of staying in Boston and allowing this opportunity of opportunities to pass unimproved. His fiancée, Miss Hubbard, expected to attend the exposition, and had heard nothing of Bell's inability to go. He went with her to the station, and as the train was leaving she learned for the first time that he was not to accompany her. She burst into tears at the disappointment. Seeing this, Bell dashed madly after the train and succeeded in boarding it. Without money or baggage, he nevertheless succeeded in arriving in Philadelphia. Bell arrived at the exposition but a few days before the judges were to make their tour of inspection. With considerable difficulty Hubbard had secured their promise that they would stop and examine the telephone. They seemed to regard it as a toy not worth their attention, and the public generally had displayed no interest in the device. When the day for the inspection arrived Bell waited eagerly. As the day passed his hope began to fall, as there seemed little possibility that the judges would reach his exhibit. The Western Union's exhibit of recording telegraphs, the self-binding harvester, the first electric light, Gray's musical telegraph, and other prominently displayed wonders had occupied the attention of the scientists. It was well past supper-time when they came to Bell's table behind the stairs, and most of the judges were tired out and loudly announced their intention of quitting then and there. At this critical moment, while they were fingering Bell's apparatus indifferently and preparing for their departure, a strange and fortunate thing occurred. Followed by a group of brilliantly attired courtiers, the Emperor of Brazil appeared. He rushed up to Bell and greeted him with a warmth of affection that electrified the indifferent judges. They watched the scene in astonishment, wondering who this young Bell was that he could attract the attention and the friendship of the Emperor. The Emperor had attended Bell's school for deaf mutes in Boston when it was at the height of its success, and had conceived a warm admiration for the young man and taken a deep interest in his work. The Emperor was ready to examine Bell's invention, though the judges were not. Bell showed him how to place his ear to the receiver, and he then went to the transmitter which had been placed at the other end of the wire strung along the room. The Emperor waited expectantly, the judges watched curiously. Bell, at a distance, spoke into the transmitter. In utter wonderment the Emperor raised his head from the receiver. "My God," he cried, "it talks!" Skepticism and indifference were at an end among the judges, and they eagerly followed the example of the Emperor. Joseph Henry, the most venerable savant of them all, took his place at the receiver. Though his previous talk with Bell, when the telephone was no more than an idea, should perhaps have prepared him, he showed equal astonishment, and instantly expressed his admiration. Next followed Sir William Thomson, the hero of the cable and England's greatest scientist. After his return to England Thomson described his sensations. "I heard," he said, "'To be or not to be ... there's the rub,' through an electric wire; but, scorning monosyllables, the electric articulation rose to higher flights, and gave me passages from the New York newspapers. All this my own ears heard spoken to me with unmistakable distinctness by the then circular-disk armature of just such another little electro-magnet as this I hold in my hand." Thomson pronounced Bell's telephone "the most wonderful thing he had seen in America." The judges had forgotten that they were hungry and tired, and remained grouped about the telephone, talking and listening in turn until far into the evening. With the coming of the next morning Bell's exhibit was moved from its obscure corner and given the most prominent place that could be found. From that time forward it was the wonder of the Centennial. [Illustration: PROFESSOR BELL'S VIBRATING REED] [Illustration: PROFESSOR BELL'S FIRST TELEPHONE] [Illustration: THE FIRST TELEPHONE SWITCHBOARD USED IN NEW HAVEN, CONN, FOR EIGHT SUBSCRIBERS] [Illustration: EARLY NEW YORK EXCHANGE Boys were employed as operators at first, but they were not adapted to the work so well as girls.] [Illustration: PROFESSOR BELL IN SALEM, MASS., AND MR. WATSON IN BOSTON, DEMONSTRATING THE TELEPHONE BEFORE AUDIENCES IN 1877] [Illustration: DR BELL AT THE TELEPHONE OPENING THE NEW YORK-CHICAGO LINE, OCTOBER 18, 1892] Yet but a small part of the public could attend the exposition and actually test the telephone for themselves. Many of these believed that it was a hoax, and general skepticism still prevailed. Business men, though they were convinced that the telephone would carry spoken messages, nevertheless insisted that it presented no business possibilities. Hubbard, however, had faith in the invention, and as Bell was not a business man, he took upon himself the work of promotion--the necessary, valuable work which must be accomplished before any big idea or invention may be put at the service of the public. Hubbard's first move was to plan a publicity campaign which should bring the new invention favorably to the attention of all, prove its claims, and silence the skeptics. They were too poor to set up an experimental line of their own, and so telegraph lines were borrowed for short periods wherever possible, demonstrations were given and tests made. The assistance of the newspapers was invoked and news stories of the tests did much to popularize the new idea. An opportunity then came to Bell to lecture and demonstrate the telephone before a scientific body in Essex. He secured the use of a telegraph line and connected the hall with the laboratory in Boston. The equipment consisted of old-fashioned box 'phones over a foot long and eight inches square, built about an immense horseshoe magnet. Watson was stationed in the Boston laboratory. Bell started his lecture, with Watson constantly listening over the telephone. Bell would stop from time to time and ask that the ability of the telephone to transmit certain kinds of sounds be illustrated. Musical instruments were played in Boston and heard in Essex; then Watson talked, and finally he was instructed to sing. He insisted that he was not a singer, but the voices of others less experienced in speaking over the crude instruments often failed to carry sufficiently well for demonstration purposes. So Watson sang, as best he could, "Yankee Doodle," "Auld Lang Syne," and other favorites. After the lecture had been completed members of the audience were invited to talk over the telephone. A few of them mustered confidence to talk with Watson in Boston, and the newspaper reporters carefully noted down all the details of the conversation. The lecture aroused so much interest that others were arranged. The first one had been free, but admission was charged for the later lectures and this income was the first revenue Bell had received for his invention. The arrangements were generally the same for each of the lectures about Boston. The names of Longfellow, of Holmes, and of other famous American men of letters are found among the patrons of some of the lectures in Boston. Bell desired to give lectures in New York City, but was not certain that his apparatus would operate at that distance over the lines available. The laboratory was on the third floor of a rooming-house, and Watson shouted so loud in his efforts to make his voice carry that the roomers complained. So he took blankets and erected a sort of tent over the instruments to muffle the sound. When the signal came from Bell that he was ready for the test, Watson crawled into the tent and began his shoutings. The day was a hot one, and by the time that the test had been completed Watson was completely wilted. But the complaints of the roomers had been avoided. For one of the New York demonstrations the services of a negro singer with a rich barytone voice had been secured. Watson had no little difficulty in rehearsing him for the part, as he objected to placing his lips close to the transmitter. When the time for the test arrived he persisted in backing away from the mouthpiece when he sang, and, though Watson endeavored to hold the transmitter closer to him, his efforts were of no avail. Finally Bell told Watson that as the negro could not be heard he would have to sing himself. The girl operator in the laboratory had assembled a number of her girl friends to watch the test, and Watson, who did not consider himself a vocalist, did not fancy the prospect. But there was no one else to sing, the demonstration must proceed, and finally Watson struck up "Yankee Doodle" in a quavering voice. The negro looked on in disgust. "Is that what you wanted me to do, boss?" "Yes," replied the embarrassed Watson. "Well, boss, I couldn't sing like that." The telegraph wires which were borrowed to demonstrate the utility of the telephone proved far from perfect for the work at hand. Many of the wires were rusted and the insulation was poor. The stations along the line were likely to cut in their relays when the test was in progress, and Bell's instruments were not arranged to overcome this retardation. However, the lectures were a success from the popular viewpoint. The public flocked to them and the fame of the telephone grew. So many cities desired the lecture that it finally became necessary for Bell to employ an assistant to give the lecture for him. Frederick Gower, a Providence newspaper man, was selected for this task, and soon mastered Bell's lecture. It was then possible to give two lectures on the same evening, Bell delivering one, Gower the other, and Watson handling the laboratory end for both. Gower secured a contract for the exclusive use of the telephone in New England, but failed to demonstrate much ability in establishing the new device on a business basis. How little the possibilities of the telephone were then appreciated we may understand from the fact that Gower exchanged his immensely valuable New England rights for the exclusive right to lecture on the telephone throughout the country. The success of these lectures made it possible for Bell to marry, and he started for England on a wedding-trip. The lectures also aroused the necessary interest and made it possible to secure capital for the establishment of telephone lines. It also determined Hubbard in his plan of leasing the telephones instead of selling them. This was especially important, as it made possible the uniformity of the efficient Bell system of the present day. XIV IMPROVEMENT AND EXPANSION The First Telephone Exchange--The Bell Telephone Association--Theodore N. Vail--The Fight with the Western Union--Edison and Blake Invent Transmitters--Last Effort of the Western Union--Mushroom Companies and Would-be Inventors--The Controversy with Gray--Dolbear's Claims--The Drawbaugh Case--On a Firm Footing. Through public interest had been aroused in the telephone, it was still very far from being at the service of the nation. The telephone increases in usefulness just in proportion to the number of your acquaintances and business associates who have telephones in their homes or offices. Instruments had to be manufactured on a commercial scale, telephone systems had to be built up. While the struggles of the inventor who seeks to apply a new idea are often romantic, the efforts of the business executives who place the invention, once it is achieved, at the service of people everywhere, are not less praiseworthy and interesting. A very few telephones had been leased to those who desired to establish private lines, but it was not until May of 1877 that the first telephone system was established with an exchange by means of which those having telephones might talk with one another. There was a burglar-alarm system in Boston which had wires running from six banks to a central station. The owner of this suggested that telephones be installed in the banks using the burglar-alarm wires. Hubbard gladly loaned the instruments for the purpose. Instruments were installed in the banks without saying anything to the bankers, or making any charge for the service. One banker demanded that his telephone be removed, insisting that it was a foolish toy. But even with the crude little exchange the first system proved its worth. Others were established in New York, Philadelphia, and other cities on a commercial basis. A man from Michigan appeared and secured the perpetual rights for his State, and for his foresight and enterprise he was later to be rewarded by the sale of these rights for a quarter of a million dollars. The free service to the Boston bankers was withdrawn and a commercial system installed there. But these exchanges served but a few people, and were poorly equipped. There was, of course, no provision for communication between cities. With the telephone over a year old, less than a thousand instruments were in use. But Hubbard, who was directing the destinies of the enterprise during Bell's absence in Europe, decided that the time had come to organize. Accordingly the Bell Telephone Association was formed, with Bell, Hubbard, Sanders, and Watson as the shareholders. Sanders was the only one of the four with any considerable sum of money, and his resources were limited. He staked his entire credit in the enterprise, and managed to furnish funds with which the fight for existence could be carried on. But a business depression was upon the land and it was not easy to secure support for the telephone. The entrance of the Western Union Telegraph Company into the telephone field brought the affairs of the Bell company to a crisis. As we have seen, the telegraph company had developed into a great and powerful corporation with wires stretching across the length and breadth of the land and agents and offices established in every city and town of importance. Once the telephone began to be used as a substitute for the telegraph in conveying messages, the telegraph officials awoke to the fact that here, possibly, was a dangerous rival, and dropped the viewpoint that Bell's telephone was a mere plaything. They acquired the inventions of Edison, Gray, and Dolbear, and entered the telephone field, announcing that they were prepared to furnish the very best in telephonic communication. This sudden assault by the most powerful corporation in America, while it served to arouse public confidence in the telephone, made it necessary for Hubbard to reorganize his forces and find a general capable of doing battle against such a foe. Hubbard's political activities had brought to him a Presidential appointment as head of a commission on mail transportation. In the course of the work for the Government he had come much in contact with a young man named Theodore N. Vail, who was head of the Government mail service. He had been impressed by Vail's ability and had in turn introduced Vail to the telephone and aroused his enthusiasm in its possibilities. This Vail was a cousin of the Alfred Vail who was Morse's co-worker, and who played so prominent a part in the development of the telegraph. His experience in the Post-office Department had given him an understanding of the problems of communication in the United States, and had developed his executive ability. Realizing the possibilities of the telephone, he relinquished his governmental post and cast his fortunes with the telephone pioneers, becoming general manager of the Bell company. The Western Union strengthened its position by the introduction of a new and improved transmitter. This was the work of Thomas Edison, and was so much better than Bell's transmitter that it enabled the Western Union to offer much better telephonic equipment. As we have seen, Bell's transmitter and receiver were very similar, being about the same as the receiver now in common use. In his transmitter Edison placed tiny bits of carbon in contact with the diaphragm. As the diaphragm vibrated under the sound-impulses the pressure upon the carbon granules was varied. An electric current was passed through the carbon particles, whose electrical resistance was varied by the changing pressure from the diaphragm. Thus the current was thrown into undulations corresponding to the sound-waves, and passed over the line and produced corresponding sounds in the receiver. Much stronger currents could be utilized than those generated by Bell's instrument, and thus the transmitter was much more effective for longer distances. Bell returned from Europe to find the affairs of his company in a sorry plight. Only the courage and generalship of Vail kept it in the field at all. Bell was penniless, having failed to establish the telephone abroad, even as Morse before him had failed to secure foreign revenue from his invention. Bell's health failed him, and as he lay helpless in the hospital his affairs were indeed at a low ebb. At this juncture Francis Blake, of Boston, came forward with an improved transmitter which he offered to the Bell company in exchange for stock. The instrument proved a success and was gladly adopted, proving just what was needed to make possible successful competition with the Western Union. Prolonged patent litigation followed, and after a bitter legal struggle the Western Union officials became convinced of two things: one, that the Bell company, under Vail's leadership, would not surrender; second, that Bell was the original inventor of the telephone and that his patent was valid. The Western Union, however, seemed to have strong basis for its claim that the new transmitter of the Bell people was an infringement of Edison's patent. A compromise was arranged between the contestants by which the two companies divided the business of furnishing communication by wire in the United States. This agreement proved of the greatest benefit to both organizations, and did much to make possible the present development and universal service of both the telephone and telegraph. By the terms of the agreement the Western Union recognized Bell's patent and agreed to withdraw from the telephone business. The Bell company agreed not to engage in the telegraph business and to take over the Western Union telephone system and apparatus, paying a royalty on all telephone rentals. Experience has demonstrated that the two businesses are not competitive, but supplement each other. It is therefore proper that they should work side by side with mutual understanding. Success had come at last to the telephone pioneers. Other battles were still to be fought before their position was to be made secure, but from the moment when the Western Union admitted defeat the Bell company was the leader. The stock of the company advanced to a point where Bell, Hubbard, Sanders, and Watson found themselves in the possession of wealth as a reward for their pioneering. The Western Union had no sooner withdrawn as a competitor of the Bell organization than scores of small, local companies sprang up, all ready to pirate the Bell patent and push the claims of some rival inventor. A very few of them really tried to establish telephone systems, but the majority were organized simply to sell stock to a gullible public. They stirred up a continuous turmoil, and made much trouble for the larger company, though their patent claims were persistently defeated in the courts. Most of the rival claimants who sprang up, once the telephone had become an established fact and had proved its value, were men of neither prominence nor scientific attainments. Of a very different type was Elisha Gray, whose work we have before noticed, and who now came forward with the claim that he had invented a telephone in advance of Bell. Gray was a practical man of real scientific attainments, but, as we have noticed, his efforts in search of a telephone were from the viewpoint of a musical telegraph and so destined to failure. It has frequently been stated that Gray filed his application for a patent on a telephone of his invention but a few minutes after Bell, and so Bell wrested the honor from him by the scantiest of margins. A careful reading of the testimony brought out in Gray's suit against Bell does not support such a statement. While Bell filed an application for a patent on a completed, invention, Gray filed, a few moments later, a caveat. This was a document, stating that he hoped to invent a telephone of a certain kind therein stated, and would serve to protect his rights until he should have time to perfect it. Thus Gray did not have a completed invention, and he later failed to perfect a telephone along the lines described in his caveat. The decision of the court supported Bell's claims in full. Another of the Western Union's telephone experts, Professor Dolbear, of Tufts College, also sought to make capital of his knowledge of the telephone. He based his claims upon an improvement of the Reis musical telegraph, which had formed the starting-point for so many experimenters. The case fell flat, however, for when the apparatus was brought into court no one could make it talk. None of the attacks upon Bell's claim to be the original inventor of the telephone aroused more popular interest at the time than the famous Drawbaugh case. Daniel Drawbaugh was a country mechanic with a habit of reading of the new inventions in the scientific journals. He would work out models of many of these for himself, and, showing them very proudly, often claim them as his own devices. Drawbaugh was now put forward by the opponents of the Bell organization as having invented a telephone before Bell. It was claimed that he had been too poor to secure a patent or to bring his invention to popular notice. Much sympathy was thus aroused for him and the legal battle was waged to interminable length, with the usual result. Bell's patent was again sustained, and Drawbaugh's claims were pronounced without merit. Many other legal battles followed, but the dominance of the Bell organization, resting upon the indisputable fact that Bell was the first man to conceive and execute a practical telephone, could not be shaken. The telephone business was on a firm footing: it had demonstrated its real service to the public; it had become a necessity; and, under the able leadership of Vail, was fast extending its field of usefulness. XV TELEGRAPHING WITHOUT WIRES The First Suggestion--Morse Sends Messages Through the Water--Trowbridge Telegraphs Through the Earth--Experiments of Preece and Heaviside in England--Edison Telegraphs from Moving Trains--Researches of Hertz Disclose the Hertzian Waves. Great as are the possibilities of the telegraph and the telephone in the service of man, these instruments are still limited to the wires over which they must operate. Communication was not possible until wires had been strung; where wires could not be strung communication was impossible. Much yet remained to be done before perfection in communication was attained, and, though the public generally considered the telegraph, and the telephone the final achievement, men of science were already searching for an even better way. The first suggestion that electric currents carrying messages might some day travel without wires seems to have come from K.A. Steinheil, of Munich. In 1838 he discovered that if the two ends of a single wire carrying the electric current be connected with the ground a complete circuit is formed, the earth acting as the return. Thus he was able to dispense with one wire, and he suggested that some day it might be possible to eliminate the wire altogether. The fact that the current bearing messages could be sent through the water was demonstrated by Morse as early as 1842. He placed plates at the termini of a circuit and submerged them in water some distance apart on one side of a canal. Other plates were placed on the opposite side of the waterway and were connected by a wire with a sensitive galvanometer in series to act as a receiver. Currents sent from the opposite side were recorded by the galvanometer and the possibility of communication through the water was established. Others carried these experiments further, it being even suggested that messages might be sent across the Atlantic by this method. But Bell's greatest contribution to the search for wireless telegraphy was not his direct work in this field, but the telephone itself. His telephone receiver provided the wireless experimenters with an instrument of extreme sensitiveness by which they were able to detect currents which the mirror galvanometer could not receive. While experimenting with a telephone along a telegraph line a curious phenomenon was noticed. The telephone experimenters heard music very clearly. They investigated and found that another telegraph wire, strung along the same poles, but at the usual distance and with the usual insulation, was being used for a test of Edison's musical telephone. Many other similar tests were made and the effect was always noted. In some way the message on one line had been conveyed across the air-gap and had been recorded by the telephones on the other line. It was decided that this had been caused by induction. Prof. John Trowbridge, of Harvard University, might well be termed the grandfather of wireless telegraphy. He made the first extensive investigation of the subject, and his experiments in sending messages without wires and his discoveries furnished information and inspiration for those who were to follow. His early experiments tested the possibility of using the earth as a conductor. He demonstrated that when an electric current is sent into the earth it spreads from that point in waves in all directions, just as when a stone is cast into a pond the ripples widen out from that point, becoming fainter and fainter until they reach the shore. He further found that these currents could be detected by grounding the terminals of a telephone circuit. Telegraphy through the earth was thus possible. However, the farther the receiving station was from the sending station the wider must be the distance between the telephone terminals and the smaller the current received. Professor Trowbridge did not find it possible to operate his system at a sufficient distance to make it of value, but he did demonstrate that the currents do travel through the earth and that they can be set to carrying messages. Professor Trowbridge also revived the idea of telegraphing across the Atlantic by utilizing the conductivity of the sea-water to carry the currents. In working out the plan theoretically he discovered that the terminals on the American side would have to be widely separated--one in Nova Scotia and the other in Florida--and that they would have to be connected by an insulated cable. Two widely separated points on the coast of France were suggested for the other terminals. He also calculated that very high voltages would be necessary, and the practical difficulties involved made it seem certain that such a system would cost far too much to construct and to operate to be profitable. Trowbridge suggested the possibility of using such a system for establishing communication between ships at sea. Ship could communicate with ship, over short distances, during a fog. A trailing wire was to be used to increase the sending and receiving power, and Trowbridge believed that with a dynamo capable of supplying current for a hundred lights, communication could be established at a distance of half a mile. Not satisfied with the earth or the sea as a medium for carrying the current, Trowbridge essayed to use the air. He believed that this was possible, and that it would be accomplished at no distant date. He believed, however, that such a system could not be operated over considerable distances because of the curvature of the earth. He endeavored to establish communication through the air by induction. He demonstrated that if one coil of wire be set up and a current sent through it, a similar coil facing it will have like currents induced within it, which may be detected with a telephone receiver. He also determined that the currents were strongest in the receiving coil when it was placed in a plane parallel with the sending coil. By turning the receiving coil about until the sound was strongest in the telephone receiver, it was thus possible to determine the direction from which the messages were coming. Trowbridge recognized the great value of this feature to a ship at sea. But these induced currents could only be detected at a distance by the use of enormous coils. To receive at a half-mile a coil of eight hundred feet radius would have been necessary, and this was obviously impossible for use on shipboard. So these experiments also developed no practical improvement in the existing means of communication. But Professor Trowbridge had demonstrated new possibilities, and had set men thinking along new lines. He was the pioneer who pointed the way to a great invention, though he himself failed to attain it. Bell followed up Trowbridge's suggestions of using the water as a medium of communication, and in a series of experiments conducted on the Potomac River established communication between moving ships. Professor Dolbear also turned from telephone experimentation to the search for the wireless. He grounded his wires and sent high currents into the earth, but improved his system and took another step toward the final achievement by adding a large induction coil to his sending equipment. He suggested that the spoken word might be sent as well as dots and dashes, and so sought the wireless telephone as well as the wireless telegraph. Like his predecessors, his experiments were successful only at short distances. The next application of the induction telegraph was to establish communication with moving trains. Several experimenters had suggested it, but it remained for Thomas A. Edison to actually accomplish it. He set up a plate of tin-foil on the engine or cars, opposite the telegraph wires. Currents could be induced across the gap, no matter what the speed of the train, and, traveling along the wires to the station, communication was thus established. Had Edison continued his investigation further, instead of turning to other pursuits, he might have achieved the means of communicating through the air at considerable distances. These experiments by Americans in the early 'eighties seemed to promise that America was to produce the wireless telegraph, as it had produced the telegraph and the telephone. But the greatest activity now shifted to Europe and the American men of science failed to push their researches to a successful conclusion. Sir W.H. Preece, an Englishman, brought himself to public notice by establishing communication with the Isle of Wight by Morse's method. Messages were sent and received during a period when the cable to the island was out of commission, and thus telegraphing without wires was put to practical use. Preece carried his experiments much further. In 1885 he laid out two great squares of insulated wire, a quarter of a mile to the side, and at a distance of a quarter of a mile from each other. Telephonic communication was established between them, and thus he had attained wireless telephony by induction. In 1887, another Englishman, A.W. Heaviside, laid circuits over two miles long on the surface and other circuits in the galleries of a coal-mine three hundred and fifty feet below, and established communication between the circuits. Working together, Preece and Heaviside extended the distances over which they could communicate. Preece finally decided that a combination of conduction and induction was the best means of wireless communication. He grounded the wire of his circuit at two points and raised it to a considerable height between these points. Preece's work was to put the theories of Professor Trowbridge to practical use and thus bring the final achievement a step nearer. But conduction and induction combined would not carry messages to a distance that would enable extensive communication. A new medium had yet to be found, and this was the work of Heinrich Hertz, a young German scientist. He was experimenting with two flat coils of wire, as had many others before him, but one of the coils had a small gap in it. Passing the discharge from a condenser into this coil, Hertz discovered that the spark caused when the current jumped the gap set up electrical vibrations that excited powerful currents in the other coil. These currents were noticeable, though the coils were a very considerable distance apart. Thus Hertz had found out how to send out electrical waves that would travel to a considerable distance. What was the medium that carried these waves? This was the question that Hertz asked himself, and the answer was, the ether. We know that light will pass through a vacuum, and these electric waves would do likewise. It was evident that they did not pass through the air. The answer, as evolved by Hertz and approved by other scientists, is that they travel through the ether, a strange substance which pervades all space. Hertz discovered that light and his electrical waves traveled at the same speed, and so deduced that light consists of electrical vibrations in the ether. With the knowledge that this all-pervading ether would carry electric waves at the speed of light, that the waves could be set up by the discharge of a spark across a spark-gap in a coil, and that they could be received in another coil in resonance with the first, the establishment of a practical wireless telegraph was not far away. XVI AN ITALIAN BOY'S WORK The Italian Youth who Dreamed Wonderful Dreams--His Studies--Early Detectors--Marconi Seeks an Efficient Detector--Devises New Sending Methods--The Wireless Telegraph Takes Form--Experimental Success. With the nineteenth century approaching its close, man had discovered that the electric waves would travel through the ether; he had learned something of how to propagate those waves, and something of how to receive them. But no one had yet been able to combine these discoveries in practical form, to apply them to the task of carrying messages, to make the improvements necessary to make them available for use at considerable distances. Though many mature scientists had devoted themselves to the problem, it remained for a youth to solve it. The youth was Guglielmo Marconi, an Italian. We have noticed that the telegraph, the cable, and the telephone were the work of those of the Anglo-Saxon race--Englishmen or Americans--so it came as a distinct surprise that an Italian youth should make the next great application of electricity to communication. But Anglo-Saxon blood flows in Marconi's veins. Though his father was an Italian, his mother was an Irishwoman. He was born at Villa Griffone near Bologna, Italy, on April 25, 1874. He studied in the schools of Bologna and of Florence, and early showed his interest in scientific affairs. From his mother he learned English, which he speaks as fluently as he does his native tongue. As a boy he was allowed to attend English schools for short periods, spending some time at Bedford and at Rugby. One of his Italian teachers was Professor Righi, who had made a close study of the Hertzian waves, and who was himself making no small contributions to the advancement of the science. From him young Marconi learned of the work which had been accomplished, and of the apparatus which was then available. Marconi was a quiet boy--almost shy. He did not display the aggressive energy so common with many promising youths. But though he was quiet, he was not slothful. He entered into his studies with a determination and an application that brought to him great results. He was a student and a thinker. Any scientific book or paper which came before him was eagerly devoured. It was this habit of careful and persistent study that made it possible for Marconi to accomplish such wonderful things at an early age. Marconi had learned of the Hertzian waves. It occurred to him that by their aid wireless telegraphy might be accomplished. The boy saw the wonderful possibilities; he dreamed dreams of how these waves might carry messages from city to city, from ship to shore, and from continent to continent without wires. He realized his own youth and inexperience, and it seemed certain to him that many able scientists had had the same vision and must be struggling toward its attainment. For a year Marconi dreamed those dreams, studying the books and papers which would tell him more of these wonderful waves. Each week he expected the news that wireless telegraphy had been established, but the news never came. Finally he concluded that others, despite their greater opportunities, had not been so far-seeing as he had thought. Marconi attacked the problem himself with the dogged persistence and the studious care so characteristic of him. He began his experiments upon his father's farm, the elder Marconi encouraging the youth and providing him with funds with which to purchase apparatus. He set up poles at the opposite sides of the garden and on them mounted the simple sending and receiving instruments which were then available, using plates of tin for his aerials. He set up a simple spark-gap, as had Hertz, and used a receiving device little more elaborate. A Morse telegraph-key was placed in circuit with the spark-gap. When the key was held down for a longer period a long spark passed between the brass knobs of the spark-gap and a dash was thus transmitted. When the key was depressed for a shorter period a dot in the Morse code was sent forth. After much work and adjustment Marconi was able to send a message across the garden. Others had accomplished this for similar distances, but they lacked Marconi's imagination and persistence, and failed to carry their experiments further. To the young Irish-Italian this was but a starting-point. [Illustration: GUGLIELMO MARCONI Photographed in the uniform of an officer in the Italian army] Marconi quickly found that the receiver was the least effective part of the existing apparatus. The waves spread in all directions from the sending station and become feebler and feebler as the distance increases. To make wireless telegraphy effective over any considerable distance a highly efficient and extremely sensitive receiving device is necessary. Some special means of detecting the feeble currents was necessary. The coherer was the solution. As early as 1870 a Mr. S.A. Varley, an Englishman, had discovered that when he endeavored to send a current through a mass of carbon granules the tiny particles arranged themselves in order under the influence of the electric current, and offered a free path for the passage of the current. When shaken apart they again resisted the flow of current until it became powerful enough to cause them to again arrange themselves into a sort of bridge for its passage. Thus was the principle of the coherer discovered. An Italian scientist, Professor Calzecchi-Onesti, carried these experiments still further. He used various substances in place of the carbon granules and showed that some of them will arrange themselves so as to allow the passage of a current under the influence of the spark setting up the Hertzian waves. Professor E. Branly, of the Catholic University of Paris, took up this work in 1890. He arranged metal filings in a small glass tube six inches long and arranged a tapper to disarrange the filings after they had been brought together under the influence of the spark. With the Branly coherer as the basis Marconi sought to make improvements which would result in the detector he was seeking. For his powder he used nickel, mixed with a small proportion of fine silver filings. This he placed between silver plugs in a small glass tube. Platinum wires were connected to the silver plugs and brought out at the opposite ends of the tube. It required long study to determine just how to adjust the plugs between which the powder was loosely arranged. If the particles were pressed together too tightly they would not fall apart readily enough under the influence of the tapper. If too much space was allowed they would not cohere readily enough. Marconi also discovered that a larger proportion of silver in the powder and a smaller amount between the plugs increased the sensitiveness of the receiver. Yet he found it well not to have it too sensitive lest it cohere for every stray current and so give false signals. Under the influence of the electric waves set up from the spark-gap those tiny particles so arranged themselves that they would readily carry a current between the plugs. By placing these plugs with their platinum terminals in circuit with a local battery the current from this local battery was given a passage through the coherer by the action of the electric waves coming through the ether. While these waves themselves were too feeble to operate a receiving mechanism, they were strong enough to arrange the particles of the sensitive metal in the tube in order, so that the current from the local battery could pass through them. This current operated a telegraph relay which in turn operated a Morse receiving instrument. An electrical tapper was also arranged in this circuit so that it would strike the tube a light blow after each long or short wave representing a dot or a dash had been received. Thus the particles were disarranged, ready to array themselves when the next wave came through the ether and so form the bridge over which the stronger local circuit could convey the signal. Marconi further discovered that the most effective arrangement was to run a wire from one terminal of the coherer into the ground, and from the other to an elevated metal plate or wire. The waves coming through the ether were received by the elevated wire and were conducted down to the coherer. Experimenting with his apparatus on the posts in the garden, he discovered that an increase in the height of the wire greatly increased the receiving distance. At his sending station he used the exciter of his teacher, Professor Righi. This, too, he modified and perfected for his practical purpose. As he used the device it consisted of two brass spheres a millimeter apart. An envelope was provided so that the sides of the spheres toward each other and the space between was occupied by vaseline oil which served to keep the faces of the spheres clean and produce a more uniform spark. Outside the two spheres, but in line with them, were placed two smaller spheres at a distance of about two-fifths of a centimeter. The terminals of the sending circuit were attached to these. The secondary coil of a large induction coil was placed in series with them, and batteries were wired in series with the primary of the coil with a sending key to make and break the circuit. When the key was closed a series of sparks sprang across the spark-gap, and the waves were thus set up in the ether and carried the message to the receiving station. As in the case of his receiving station, Marconi found that results were much improved when he wired his sending apparatus so that one terminal was grounded and the other connected with an elevated wire or aerial, which is now called the antenna. By 1896 Marconi had brought this apparatus to a state of perfection where he could transmit messages to a distance of several miles. This Irish-Italian youth of twenty-two had mastered the problem which had baffled veteran scientists and was ready to place a new wonder at the service of the world. The devices which Marconi thus assembled and put to practical use had been, in the hands of others, little more than scientific toys. Others had studied the Hertzian waves and the methods of sending and detecting them from a purely scientific viewpoint. Marconi had the vision to realize the practical possibilities, and, though little more than a boy, had assembled the whole into a workable system of communication. He richly deserves the laurels and the rewards as the inventor of the wireless telegraph. XVII WIRELESS TELEGRAPHY ESTABLISHED Marconi Goes to England--he Confounds the Skeptics--A Message to France Without Wires--The Attempt to Span the Ocean--Marconi in America Receives the First Message from Europe--Fame and Recognition Achieved. The time had now come for Marconi to introduce himself and his discoveries to the attention of the world. He went to England, and on June 2, 1896, applied for a patent on his system of wireless telegraphy. Soon afterward his plans were submitted to the postal-telegraph authorities. Fortunately for Marconi and for the world, W.H. Preece was then in authority in this department. He himself had experimented with some little success with wireless messages. He was able enough to see the merit in Marconi's discoveries and generous enough to give him full recognition and every encouragement. The apparatus was first set up in the General Post-office in London, another station being located on the roof but a hundred yards away. Though several walls intervened, the Hertzian waves traversed them without difficulty, and messages were sent and received. Stations were then set up on Salisbury Plain, some two miles apart, and communication was established between them. Though the postal-telegraph authorities received Marconi's statements of his discoveries with open mind and put his apparatus to fair tests, the public at large was much less tolerant. The skepticism which met Morse and Bell faced Marconi. Men of science doubted his statements and scoffed at his claims. The Hertzian waves might be all right to operate scientific playthings, they thought, but they were far too uncertain to furnish a medium for carrying messages in any practical way. Then, as progress was made and Marconi began to prove his system, the inevitable jealousies arose. Experimenters who might have invented the wireless telegraph, but who did not, came forward to contest Marconi's claims and to seek to snatch his laurels from him. The young inventor forged steadily ahead, studying and experimenting, devising improved apparatus, meeting the difficulties one by one as they arose. In most of his early experiments he had used a modification of the little tin boxes which had been set up in his father's garden as his original aerials. Having discovered that the height of the aerials increased the range of the stations, he covered a large kite with tin-foil and, sending it up with a wire, used this as an aerial. Balloons were similarly employed. He soon recognized, however, that a practical commercial system, which should be capable of sending and receiving messages day and night, regardless of the weather, could not be operated with kites or balloons. The height of masts was limited, so he sought to increase the range by increasing the electrical power of the current sending forth the sparks from the sending station. Here he was on the right path, and another long step forward had been taken. In the fall of 1897 he set up a mast on the Isle of Wight, one hundred and twenty feet high. From the top of this was strung a single wire and a new series of experiments was begun. Marconi had spent the summer in Italy demonstrating his apparatus, and had established communication between a station on the shore and a war-ship of the Italian Navy equipped with his apparatus. He now secured a small steamer for his experiments from his station on the Isle of Wight and equipped it with a sixty-foot mast. Communication was maintained with the boat day after day, regardless of weather conditions. The distance at which communication could be maintained was steadily increased until communication was established with the mainland. In July of 1898 the wireless demonstrated its utility as a conveyer of news. An enterprising Dublin newspaper desired to cover the Kingstown regatta with the aid of the wireless. In order to do this a land station was erected at Kingstown, and another on board a steamer which followed the yachts. A telephone wire connected the Kingstown station with the newspaper office, and as the messages came by wireless from the ship they were telephoned to Dublin and published in successive editions of the evening papers. This feat attracted so much attention that Queen Victoria sought the aid of the wireless for her own necessities. Her son, the Prince of Wales, lay ill on his yacht, and the aged queen desired to keep in constant communication with him. Marconi accordingly placed one station on the prince's yacht and another at Osborne House, the queen's residence. Communication was readily maintained, and one hundred and fifty messages passed by wireless between the prince and the royal mother. While the electric waves bearing the messages were found to pass through wood, stone, or earth, it was soon noticed in practical operation that when many buildings, or a hill, or any other solid object of size intervened between the stations the waves were greatly retarded and the messages seriously interfered with. When the apparatus was placed on board steel vessels it was found that any part of the vessel coming between the stations checked the communication. Marconi sought to avoid these difficulties by erecting high aerials at every point, so that the waves might pass through the clear air over solid obstructions. Marconi's next effort was to connect France with England. He went to France to demonstrate his apparatus to the French Government and set up a station near Boulogne. The aerial was raised to a height of one hundred and fifty feet. Another station was erected near Folkestone on the English coast, across the Channel. A group of French officials gathered in the little station near Folkestone for the test, which was made on the 27th of March, 1899. Marconi sent the messages, which were received by the station on the French shore without difficulty. Other messages were received from France, and wireless communication between the nations was an accomplished fact. The use of the wireless for ships and lighthouses sprang into favor, and wireless stations were established all around the British coasts so that ships equipped with wireless might keep in communication with the land. The British Admiralty quickly recognized the value of wireless telegraphy to war vessels. While field telegraphs and telephones had served the armies, the navies were still dependent upon primitive signals, since a wire cannot be strung from ship to ship nor from ship to shore. So the British battle-ships were equipped with wireless apparatus and a thorough test was made. A sham battle was held in which all of the orders were sent by wireless, and communication was constantly maintained both between the flag-ships and the vessels of their fleets and between the flag-ships and the shore. Marconi's invention had again proved itself. The wireless early demonstrated its great value as a means of saving life at sea. Lightships off the English coast were equipped with the wireless and were thus enabled to warn ships of impending storms, and on several occasions the wireless was used to summon aid from the shore when ships were sinking because of accidents near the lightship. Following the establishment of communication with France, Marconi increased the range of his apparatus until he was able to cover most of eastern Europe. In one of his demonstrations he sent messages to Italy. His ambition, however, was to send messages across the Atlantic, and he now attacked this stupendous task. On the coast of Cornwall, England, he began the construction of a station which should have sufficient power to send a message to America. Instead of using a single wire for his aerial, he erected many tall poles and strung a number of wires from pole to pole. The comparatively feeble batteries which had furnished the currents used in the earlier efforts were replaced with great power-driven dynamos, and converters were used instead of the induction coil. Thus was the great Poldhu station established. Late in 1901 Marconi crossed to America to superintend the preparations there, and that he himself might be ready to receive the first message, should it prove possible to span the ocean. Signal Hill, near St. John's, Newfoundland was selected as the place for the American station. The expense of building a great aerial for the test was too great, and so dependence was had upon kites to send the wires aloft. For many days Marconi's assistants struggled with the great kites in an effort to get them aloft. At last they flew, carrying the wire to a great height. The wire was carried into a small Government building near by in which Marconi stationed himself. At his ear was a telephone receiver, this having been substituted for the relay and the Morse instrument because of its far greater sensitiveness. Marconi had instructed his operator at Poldhu to send simply the letter "s" at an hour corresponding to 12.30 A.M. in Newfoundland. Great was the excitement and suspense in Cornwall when the hour for the test arrived. Forgetting that they were sleepy, the staff crowded about the sending key, and the little building at the foot of the ring of great masts supporting the aerial shook with the crash of the blinding sparks as the three, dots which form the letter "s" were sent forth. Even greater was the tension on the Newfoundland coast, where Marconi sat eagerly waiting for the signal. Finally it came, three faint ticks in the telephone receiver. The wireless had crossed the Atlantic. Marconi had no sending apparatus, so that it was not until the cable had carried the news that those in England knew that the message had been received. Because Marconi had never made a statement or a claim he had not been able to prove, he had attained a reputation for veracity which made his statement that he had received a signal across the Atlantic carry weight with the scientists. Many, of course, were skeptical, and insisted that the simple signal had come by chance from some ship not far away. But the inventor pushed quietly and steadily ahead, making arrangements to perfect the system and establish it so that it would be of commercial use. Marconi returned to England, but two months later set out for America again on the liner _Philadelphia_ with improved apparatus. He kept in constant communication with his station at Poldhu until the ship was a hundred and fifty miles from shore. Beyond that point he could not send messages, as the sending apparatus on the ship lacked sufficient power. Messages were received, however, until the sending station was over two thousand miles away. This seemed miraculous to those on shipboard, but Marconi accepted it as a matter of course. He had equipped the Poldhu station to send twenty-one hundred miles, and he knew that it should accomplish the feat. A large station was set up at Cape Breton, Nova Scotia, and regular communication was established between there and Poldhu. With the establishment of regular transatlantic communication the utility of Marconi's invention, even for work at great distances, was no longer open to question. By quiet, unassuming, conscientious work he had put another great carrier of messages at the service of the world, and he now reaped the fame and fortune which he so richly deserved. XVIII THE WIRELESS SERVES THE WORLD Marconi Organized Wireless Telegraphy Commercially--The New Wonder at the Service of the World--Marine Disasters Prevented--The Extension of the Wireless on Shipboard--Improved Apparatus--The Wireless in the World War--The Boy and the Wireless. With his clear understanding of the possibilities of his invention, Marconi was not long in establishing the wireless upon a commercial basis. He is a man of keen business judgment, and as he brought his invention forward and clearly demonstrated its worth at a time when commercial enterprise was alert he found no great difficulty in establishing his company. The first Marconi company was organized as early as 1897 under the name of the Wireless Telegraph and Signal Company, Limited. This was later displaced by the Marconi Telegraph Company, which operates a regular system of stations on a commercial basis, carrying messages in competition with the cable and telegraph companies. It also erects stations for other companies which are operated under the Marconi patents. With the telegraph and the telephone so well established and serving the needs of ordinary communication on land, it was natural that the wireless should make headway but slowly as a commercial proposition between points on land. For communication at sea, however, it had no competition, and merchant-ships as well as war vessels were rapidly equipped with wireless apparatus. When the great liner _Republic_ was sinking as a result of a collision off the port of New York in 1903 her wireless brought aid. Her passengers and crew were taken off in safety, and what otherwise would have been a terrible disaster was avoided by the use of the wireless. The utility of the wireless was again brought sharply to the attention of the world. It was realized that a wireless set on a passenger-ship was necessary if the lives of the passengers were to be safeguarded. The United States Government by its laws now requires that passenger-ships shall be equipped with wireless apparatus in charge of a competent operator. One of the early objections made to the wireless was its apparent lack of secrecy, since any other receiving apparatus within range of the waves sent forth by the sending station can receive the signals. It was also realized that as soon as any considerable number of stations were established about the world, and began sending messages to and fro, there would be a perfect jumble of waves flying about in all directions through the ether, so that no messages could be sent or received. Marconi's answer to these difficulties was the tuning apparatus. The electric waves carrying the messages may be sent out at widely varying lengths. Marconi found that it was possible to adjust a receiving station so that it would receive only waves of a certain length. Thus stations which desired to communicate could select a certain wave-length, and they could send and receive messages without interfering with others using different wave-lengths, or without the receiving station being confused by messages coming in from other stations using different wave-lengths. You know that when a tuning-fork is set in vibration another of the same pitch near it will vibrate with it, but others of different pitch will not be affected. The operation of wireless stations in tune with each other is similar. [Illustration: A REMARKABLE PHOTOGRAPH TAKEN OUTSIDE OF THE CLIFDEN STATION WHILE MESSAGES WERE BEING SENT ACROSS TO CAPE RACE The camera was exposed for two hours, and the white bars show the sparks leaving the wires for their journey through the air for seventeen hundred miles.] [Illustration: MARCONI STATION AT CLIFDEN, IRELAND These dynamos send a message straight across the ocean.] An example of the value of tuning is afforded by the manner in which press reports are sent from the great Marconi station at Poldhu. Each night at a certain hour this station sends out news reports of the events of the day, using a certain set wave-length. Each ship on the Atlantic and every land station within range which is to receive the reports at that hour adjusts its receiving set to receive waves of that length. In this way they hear nothing but the Poldhu news reports which they desire to receive, and are not troubled by messages from other stations within range. Secrecy is also attained by the use of tuning. It is possible that another station may discover the wave-length being used for a secret message and "listen in," but there are so many possible wave-lengths that this is difficult. Secrecy may also be secured by the use of code messages. Many of the advantages of tuning were lost by the international agreement which provided that but two wave-lengths should be used for commercial work. This, however, enables ships to get in touch with other ships in time of need. With his telephone receivers the operator can hear the passage of the waves as they are brought to him by his aerial and the dots and dashes sound as buzzes of greater or less length. Out of the confusion of currents passing through the air he can select the messages he wishes to read by sound. You may wonder how one wireless operator gets into communication with another. He first listens in to determine whether messages are coming through the ether within range in the wave-length he is to use. Hearing nothing, he adjusts his sending apparatus to the desired wave-length and switches this in with the signal aerial which serves both his sending and his receiving set. This at the same time disconnects his receiving set. He sends out the call letters of the station to which he wishes to send a message, following them with his own call letters, as a signature to show who is calling. After repeating these signals several times he switches out his sending set and listens in with his receiving set. If he then gets an answer from the other station he can begin sending the message. Marconi was not allowed to hold the wireless field unmolested. Many others set up wireless stations, some of them infringing upon Marconi's patents. Others have devised wireless systems along more original lines. Particularly we should mention two American experimenters, Dr. de Forest and Professor Fessenden. Both have established wireless systems with no little promise. The system of Professor Fessenden is especially unique and original and may be destined to work a revolution in the methods of wireless telegraphy. With an increase in the number of wireless stations and varieties of apparatus came a wide increase in the uses to which wireless telegraphy was applied. We have already noticed the press service from Poldhu. The British Government makes use of this same station to furnish daily news to its representatives in all parts of the world. The wireless is also used to transmit the time from the great observatories. Some of the railroads in the United States have equipped their trails as well as their stations with wireless sets. It has proved its worth in communicating between stations, taking the place in time of need of either the telegraph or the telephone. In equipping the trains with sets a difficulty was met in arranging the aerials. It is, of course, impossible to arrange the wires at any height above the cars, since they would be swept away in passing under bridges. Even with very low aerials, however, communication has been successfully maintained at a distance of over a hundred miles. The speed of the fastest train affects the sending and receiving of messages not at all. It was also found that messages passed without hindrance, even though the train was passing through a tunnel. Another interesting application of wireless telegraphy is to the needs of the fire-fighters. Fire stations in New York City have been equipped with wireless telegraph sets, and they have proved so useful in spreading alarms and transmitting news of fires that they seem destined to come into universal use. The outbreak of the world war gave a tremendous impetus to the development of wireless telegraphy. The German cable to the United States was cut in the early days of the conflict. The sending power of wireless stations had been sufficiently increased, however, so that the great German stations could communicate with those in the United States. Communication was readily maintained between the Allies by means of wireless, the great stations at Poldhu and at the Eiffel Tower in Paris being in constant communication with each other and with the stations in Italy and in Russia. Portable field sets had been used with some slight success even in the Boer War, and had definitely proved their worth in the Balkans. The outbreak of the greater war found all of the nations equipped with portable apparatus for the use of their armies. These proved of great use. The field sets of the United States Army also proved their utility in the campaign into Mexico in pursuit of Villa. By their means it was possible for General Pershing's forces to keep in constant touch with the headquarters in the United States. The wireless proved as valuable to the navies as had been anticipated. The Germans in particular made great improvements in light wireless sets designed for use on aircraft. The problem of placing an aerial on an aeroplane is difficult, but no little headway has been made in this direction. It is the American boy who has done the most interesting work with the wireless in the United States. While the commercial development has been comparatively slow, the boys have set up stations by the thousands. Most of these stations were constructed by the boys themselves, who have learned and are learning how best to apply this modern wonder to the service of man. So many amateurs set up stations that the Government found it necessary to regulate them by law. The law now requires that amateur experimenters use only short wave-lengths in their sending, which will not interfere with messages from Government or commercial stations. It also provides for the licensing of amateurs who prove competent. The stations owned and operated by boys have already proved of great use. In times of storm and flood when wire communication failed they have proved the only means of communicating with many districts. In time of war these amateur stations, scattered in all parts of the country, might prove immensely valuable. Means have now been taken to so organize the amateurs that they can communicate with one another, and by this means messages may be sent to any part of the country. One young American, John Hays Hammond, Jr., has applied the wireless in novel and interesting ways. By means of special apparatus mounted on a small boat he can by the means of a wireless station on shore start or stop the vessel, or steer it in any direction by his wireless control. He has applied the same system to the control of torpedoes. By this means a torpedo may be controlled after it has left the shore and may be directed in any direction as long as it is within sight. This invention may prove of incalculable benefit should America be attacked by a foreign power. What startling developments of wireless telegraphy lie still in the future we do not know. Marconi has predicted that wireless messages will circle the globe. "I believe," he has said, "that in the near future a wireless message will be sent from New York completely around the world without relaying, and will be received by an instrument in the same office with the transmitter, in perhaps less time than Shakespeare's forty minutes." Not long ago the United States battle-ship _Wyoming_, lying off Cape Henry on the Atlantic coast, communicated with the _San Diego_ at Guaymas, on the Pacific coast of Mexico. This distance, twenty-five hundred miles across land, shows that Marconi's prediction may be realized in the not distant future. XIX SPEAKING ACROSS THE CONTINENT A New "Hello Boy" in Boston--Why the Boy Sought the Job--The Useful Things the Boy Found to Do--Young Carty and the Multiple Switchboard--Called to New York City--He Quiets the Roaring Wires--Carty Made Engineer-in-Chief--Extending the Range of the Human Voice--New York Talks to San Francisco Over a Wire. It seemed to many that the wireless telegraph was to be the final word in the development of communication, but two striking achievements coming in 1915 proved this to be far from the case. While one group of scientists had given themselves to experimentation with the Hertzian waves which led to wireless telegraphy, other scientists and engineers were busily engaged in bringing the telephone to a perfection which would enable it to accomplish even more striking feats. These electrical pioneers did not work as individuals, but were grouped together as the engineering staff of the American Telephone and Telegraph Company. At their head was John J. Carty, and it was under his guiding genius that the great work was accomplished. John Carty is the American son of Irish parents. He was born in Cambridge, Massachusetts, on April 14, 1861. His father was a gun-maker and an expert mechanic of marked intelligence and ingenuity who numbered among his friends Howe, the creator of the sewing-machine. As a boy John Carty displayed the liveliest interest in things electrical. When the time came for him to go to school, physics was his favorite study. He showed himself to be possessed of a keen mind and an infinite capacity for work. To these advantages was added a good elementary education. He was graduated from Cambridge Latin School, where he prepared for Harvard University. Before he could enter the university his eyesight failed, and the doctor forbade continuance of study. Many a boy would have been discouraged by this physical handicap which denied him complete scholastic preparation. But this boy was not the kind that gives up. He had been supplementing his school work in physics with experimentations upon his own behalf. Let us let Mr. Carty tell in his own words how he next occupied himself. I had often visited the shop of Thomas Hall, at 19 Bromfield Street, and looked in the window. I went in from time to time, not to make large purchases, but mostly to make inquiries and to buy some blue vitriol, wire, or something of the kind. It was a store where apparatus was sold for experimentation in schools, and on Saturdays a number of Harvard and Institute of Technology professors could be found there. It was quite a rendezvous for the scientific men in those days, just the same as the Old Corner Bookstore at the corner of School and Washington Streets was a place where the literary men used to congregate. Don't think that I was an associate of these great scientists, but I was very much attracted to the atmosphere of that store. I wanted to get in and handle the apparatus. Finally it occurred to me that I would like to get into the business, somehow. But I did not have the courage to go in and ask them for a job. One day I was going by and saw a sign hanging out, "Boy Wanted." I was about nineteen, and really thought I was something of a scientist, not exactly a boy. I was a boy, however. I walked by on one side of the street and then on the other, looking in, and finally the idea possessed me to go in and strike for that job. So I took down the sign, which was outside the window, put it under my arm, and went in and persuaded Tom Hall that I was the boy he wanted. He said, "When can you begin?" I said, "Now." There was no talk of wages or duties. He said, "Take this package around to Earle & Prew's express and hurry back, as I have another errand for you to do." So I had to take a great, heavy box around to the express-office and get a receipt for it. I found, when Saturday night came around, that I had been engaged at the rate of fifty cents a day. I would have been glad to work for nothing. Well, I did not get near that apparatus in a hurry, not until the time came for fixing up the window. My first talk in regard to it had no reference to services in a scientific capacity on my part. I had rather hoped that the boss would come around and consult with, me as to how to adjust the apparatus. But that was not it. He said: "John, clean out that window. Everything is full of dust, and be careful and don't break anything!" So I cleaned it out. I swept out the place, cleaned about there, did errands, mixed battery solutions, and got a great deal of experience there in one way or another. I did whatever there was to do and got a good deal of fun out of it, while becoming acquainted with the state of the art of that day. I got to know intimately all the different sorts of philosophical apparatus there were, and how to mix the various battery solutions. In fact, I became really quite experienced for those times in such matters. It was not long before young Carty lost his job. Being a regular boy, he had been guilty of too much skylarking. This experience steadied him, and he forthwith sought a new job. He had met some of the employees of the telephone company and was naturally interested in their work. At that time "hello boys" held sway in the crude telephone exchanges, the "hello girl" having not yet appeared. So John Carty at the age of nineteen went to work in the Boston telephone exchange. The switchboard at which they placed him had been good enough for the other boys who had been called upon to operate it, and indeed it represented the best thought and effort of the leaders in the telephone world. But it did not satisfy Carty, who, not content with simply-operating the board, studied its construction and began planning improvements. As Mr. Carty himself puts it: The little switchboards of that day were a good deal like the automobiles of some years ago--one was likely to spend more time under the switchboard than, sitting at it! In that way I learned a great deal about the arrangement and construction of switchboards. Encountering the trouble first, I had an advantage over others in being able to suggest a remedy. So I have always thought it was a good thing to have troubles, as long as they are not too serious or too numerous. Troubles are certainly a great advantage, if we manage them correctly. Certainly Carty made these switchboard troubles the first stepping-stone in his climb to the top in the field of telephone engineering. The improvements which the youngster suggested were so valuable that they were soon being made under his direction, and ere long he installed in the Boston exchange the first multiple switchboard, the fundamental features of which are in the switchboards of to-day. In his work with the switchboards young Carty early got in touch with Charles E. Scribner, another youngster who was doing notable work in this field. The young men became fast friends and worked much together. Scribner devoted himself almost exclusively to switchboards and came to be known as the father of the modern switchboard. Boston had her peculiar problems and an "express" service was needed. How to handle this in the exchange was another problem, and this, too, Carty solved. For this purpose he designed and installed the first metallic circuit, multiple switchboard to go into service. The problems of the exchange were among the most serious of the many which troubled the early telephone companies. Of course every telephone-user desired to be able to converse with any other who had a telephone in his office or residence. The development of the switchboards had been comparatively slow in the past, and the service rendered by the boys proved far from satisfactory. The average boy proved himself too little amenable to discipline, too inclined to "sass" the telephone-users, and too careless. But the early use of "hello boys" was at least a success for the telephone in that it brought to its service John J. Carty. This boy pointed the way to the great improvements that made it possible to handle the constantly growing volume of calls expeditiously and effectively. The early telephones were operated with a single wire grounded at either end, the earth return being used to complete the circuit as with the telegraph. But while the currents used to operate the telegraph are fairly strong and so can dominate the earth currents, the tiny currents which represented the vibrations of the human voice were all too often drowned by the earth currents which strayed on to the lines. Telephone engineers were not then agreed that this caused the difficulty; but they did know there was difficulty. Many weird noises played over the lines and as often as not the spoken word was twisted into the strangest gibberish and rendered unintelligible. If the telephone was to satisfy its patrons and prove of real service to the world, the difficulty had to be overcome. Some of the more progressive engineers insisted that a double-wire system without a ground was necessary. This, of course, involved tremendous expenses in rebuilding every line and duplicating every wire. The more conservative hesitated, but Carty forged ahead. In 1880 he was engaged in operating a new line out of Boston. He was convinced that the double-wire system alone could be successful, and he arranged to operate a line on this plan. Taking two single lines, he instructed the operator at the other end to join them, forming a two-wire circuit. The results justified him. At last a line had been attained which could be depended upon to carry the conversation. No sooner was one problem solved than another presented itself. What to do with the constantly increasing number of wires was a pressing difficulty. All telephone circuits had been strung overhead, and with the demand for telephones for office and residence rapidly increasing, the streets of the great cities were becoming a perfect forest of telephone poles, with the sky obscured by a maze of wires. Poles were constantly increased in height until a line was strung along Wall Street in New York City at a height of ninety feet. From the poles the wires overflowed to the housetops, increasing the difficulty of the engineers. How to protect the wires so that they could be placed underground was the problem. We have noticed that Theodore Vail had been brought to the head of the Bell system in its infancy and had led the fight against the rival companies until it was thoroughly established. Now he was directing his genius and executive ability to so improving the telephone that it should serve every need of communication. While the engineers discussed theories Vail began actual tests. A trench five miles long was dug beside a railway track by the simple expedient of hitching a plow to a locomotive. In this trench were laid a number of wires, each with a different covering. The gutta-percha and the rubber coverings which had been used in cable construction predominated. It was found that these wires would carry the telephone currents, not as well as might be desired, but well enough to assure Vail that he was on the right track. The companies began to place their wires underground, and Vail saw to it that the experiments with coverings for telephone wires were continued. The result was the successful underground cables in use to-day. At the same time Vail and his engineers were seeking to improve the wires themselves. Iron and steel wires had been used, but they proved unsatisfactory, as they rusted and were poor conductors. Copper was an excellent conductor, but the metal in the pure state is soft and no one then knew how to make a copper wire that would sustain its own weight. But Vail kept his men at the problem and the hard-drawn copper wire was at length evolved. This proved just what was needed for the telephone circuits. The copper wire was four times as expensive as the iron, but as it was four times as good Vail adopted it. John Carty had rather more than kept pace with these improvements. He was but twenty-six years of age when Union N. Bethell, head of the New York company, picked Carty to take charge of the telephone engineering work in the metropolis. Bethell was Vail's chief executive officer, and under him Carty received an invaluable training in executive work. Carty's largest task was putting the wires underground, and here again he was a tremendous success. He found ways to make cables cheaper and better, and devised means of laying them at half the former cost. Having solved the most pressing problems in this field, his employers, who had come to recognize his marked genius, set him to work again on the switchboard. He was placed in charge of the switchboard department of the Western Electric Company, the concern which manufactures the apparatus for the telephone company. The switchboard, as we have seen, was Carty's first love, and again he pointed the way to great improvements. Most of the large switchboards of that time were installed under his direction, and they were better switchboards than had ever been known before. Up to this time it had been thought necessary to have individual batteries supplying current to each line. These were a constant source of difficulty, and Carty directed his own attention, and that of his associate engineers, to finding a satisfactory solution. He sought a method of utilizing one common battery at the central station and the way was found and the improvement accomplished. Though the telephone circuits were now protected from the earth, telephone-users, at times when the lines were busy, were still troubled with roarings and strange cross-talk. Though busy with the many engineering problems which the telephone heads had assigned to him, Carty found time for some original research. He showed that the roarings in the wires were largely caused by electro-static induction. In 1889 he read a paper before the Electric Club that startled the engineers of that day. He demonstrated that in every telephone circuit there is a particular point at which, if a telephone is inserted, no cross-talk can be heard. He had worked out the rules for determining this point. Thus he had at once discovered the trouble and prescribed the cure. Of course it could not be expected that the sage experts would all agree with young Carty right away; but they were forced to in the end, for again he was proved right. By 1901 Carty was ready with another invention which was to place the telephone in the homes of hundreds of thousands who, without it, could scarcely have afforded this modern necessity. This was the "bridging bell" which made possible the party line. By its use four telephones could be placed on a single line, each with its own signal, so that any one could be rung without ringing the others. Its introduction inaugurated a new boom in the use of the telephone. Theodore Vail had resigned from his positions with the telephone companies in 1890 with the determination to retire from business. But when the panic of 1907 came the directors of the company went to him on his Vermont farm and pleaded with him to return and again resume the leadership. Other and younger men would not do in this business crisis. They also pointed out that the nation's telephones had not yet been molded into the national system which had been his dream--a system of universal service in which any one at any point in the country might talk by telephone with any other. So Vail re-entered the telephone field and again took the presidency of the American Telephone and Telegraph Company. One of his first official acts was to appoint John J. Carty his chief engineer. Vail had selected the right man to make his dreams come true; Carty now had the executive who would make it possible for him to accomplish even larger things. He set about building up the engineering organization which was to accomplish the work, selecting the most brilliant graduates of American technical schools. He set this organization to work upon the extension and development of the long-distance telephone lines. As a "hello boy" Carty had believed in the possibility of the long-distance telephone when others had scoffed. He has told of an early experience while in the Boston exchange: One hot day an old lady toiled up the inevitable flights of stairs which led to the telephone-office of those times. Out of breath, she sat down, and when she had recovered sufficiently to speak she said she wanted to talk to Chicago. My colleagues of that time were all what the ethnologists would rank a little bit lower than the wild Indian. These youngsters set up a great laugh; and, indeed, the absurdity of the old lady's project could hardly be overstated, because at that time Salem was a long-distance line, Lowell sometimes worked, and Worcester was the limit--that is, in every sense of the word. The Lowell line was so unreliable that we had a telegraph operator there, and when the talk was not possible, he pushed the message through by Morse. It is no wonder that the absurdity of the old lady's proposal was the cause of poorly suppressed merriment. But I can remember that I explained to her that our wires had not yet been extended to Chicago, and that, after she had departed, I turned to the other operators and said that the day would come when we could talk to Chicago. My prophecy was received with what might be called--putting it mildly--vociferous discourtesy. Nevertheless, I remember very well the impression which that old lady's request made upon me; and I really did believe that, some day or other, in some way, we would be able to talk to Chicago. By 1912 it was possible to talk from New York to Denver, a distance of 2,100 miles. No European engineers had achieved any such results, and this feat brought to Carty and his wonderful staff the admiration of foreign experts. But for the American engineers this was only a starting-point. The next step was to link New York and California. This was more than a matter of setting poles and stringing wires, stupendous though this task was. The line crosses thirteen States, and is carried on 130,000 poles. Three thousand tons of wire are used in the line. The Panama Canal took nine years to complete, and cost over three hundred million dollars; but within that time the telephone company spent twice that amount in engineering construction work alone, extending the scope of the telephone. The technical problems were even more difficult. Carty and his engineers had to find a way to send something three thousand miles with the breath as its motive power. It was a problem of the conservation of the tiny electric current which carried the speech. The power could not be augmented or speech would not result at the destination. Added to the efforts of these able engineers was the work of Prof. Michael I. Pupin, of Columbia University, whose brilliant invention of the loading coil some ten years before had startled the scientific world and had increased the range of telephonic transmission through underground cables and through overhead wires far beyond what had formerly been possible. Professor Pupin applied his masterful knowledge of physics and his profound mathematical attainments so successfully to the practical problems of the transmission of telephone speech that he has been called "the telephone scientist." It is impossible to talk over long-distance lines anywhere in America without speaking through Pupin coils, which are distributed throughout the hundreds of thousands of miles of wire covering the North American continent. In the transcontinental telephone line Pupin coils play a most important part, and they are distributed at eight-mile intervals throughout its entire length from the Atlantic to the Pacific. In speaking at a dinner of eminent scientists, Mr. Carty once said that on account of his distinguished scientific attainments and wonderful telephonic inventions, Professor Pupin would rank in history alongside of Bell himself. We have seen how Alexander Graham Bell, standing in the little room in Boston, spoke through the crude telephone he had constructed the first words ever carried over a wire, and how these words were heard and understood by his associate, Thomas Watson. This was in 1876, and it was in January of 1915--less than forty years later--that these two men talked across the continent. The transcontinental line was complete. Bell in the offices of the company in New York talked freely with Watson in San Francisco, and all in the most conversational tone, without a trace of the difficulty that had attended their first conversation over the short line. Thus, within the span of a single life the telephone had been developed from a crude instrument which transmitted speech with difficulty over a wire a hundred feet long, until one could be heard perfectly, though over three thousand miles of wire intervened. The spoken word travels across the continent almost instantaneously, far faster than the speed of sound. If it were possible for one to be heard in San Francisco as he shouted from New York through the air, four hours would be required before the sound would arrive. Thus the telephone has been brought to a point of perfection where it carries sound by electricity and reproduces it again far more rapidly and efficiently than sound can be transmitted through its natural medium. XX TELEPHONING THROUGH SPACE The Search for the Wireless Telephone--Early Successes--Carty and His Assistants Seek the Wireless Telephone--The Task Before Them--De Forest's Amplifier--Experimental Success Achieved--The Test--Honolulu and Paris Hear Arlington--The Future. No sooner had Marconi placed the wireless telegraph at the service of the world than men of science of all nations began the search for the wireless telephone. But the vibrations necessary to reproduce the sound of the human voice are so infinitely more complex than those which will suffice to carry signals representing the dots and dashes of the telegraph code that the problem long defied solution. Scientists attacked the problem with vigor, and various means of wireless telephony were developed, without any being produced which were effective over sufficient ranges to make them really useful. Probably the earliest medium chosen to carry wireless speech was light rays. A microphone transmitter was arranged so that the vibrations of the voice would affect the stream of gas flowing in a sensitive burner. The flame was thus thrown into vibrations corresponding to the vibrations of sound. The rays from this flame were then directed by mirrors to a distant receiving station and there concentrated on a photo-electric selenium cell, which has the strange property of varying its resistance according to the illumination. Thus a telephone receiver arranged in series with it was made to reproduce the sounds. This strange, wireless telephone was so arranged that a search-light beam could be used for the light path, and distances up to three miles were covered. Even with this limited range the search-light telephone had certain advantages. Its message could be received only by those in the direct line of the light. Neither did it require aerial masts or wires and a trained telegrapher who could send and receive the telegraph code. It was put to some use between battle-ships and smaller craft lying within a radius of a few miles. The sensitive selenium cell proved unreliable, however, and this means of communication was destined to failure. The experimenters realized that future success lay in making the ether carry telephonic currents as it carried telegraphic currents. They succeeded in establishing communication without wires, using the same antenna as in wireless telegraphy, and the principles determined are those used in the wireless telephone of to-day. The sending apparatus was so arranged that continuous oscillations are set up in the ether, either by a high-frequency machine or from an electric arc. Where set up by spark discharges the spark frequency must be above twenty thousand per second. This unbroken wave train does not affect the telephone and is not audible in a telephone receiver inserted in the radio receiving circuit. But when a microphone transmitter is inserted in the sending circuit, instead of the make-and-break key used for telegraphy, the waves of the voice, thrown against the transmitter in speaking, break up the waves so that the telephone receiver in the receiving circuit will reproduce sound. Here was and is the wireless telephone. Marconi and many other scientists were able to operate it successfully over comparatively short distances, and were busily engaged in extending its range and improving the apparatus. One great difficulty involved was in increasing the power of the sending apparatus. Greater range has been secured in wireless telegraphy by using stronger sending currents. But the delicate microphone would not carry these stronger currents. Increased sensitiveness in the receiving apparatus was also necessary. Not content with their accomplishments in increasing the scope of the wire telephone, the engineers of the Bell organization, headed by John J. Carty, turned their attention to the wireless transmission of speech. Determined that the existing telephone system should be extended and supplemented in every useful way, they attacked the problem with vigor. It was a problem that had long baffled the keenest of European scientists, including Marconi himself, but that did not deter Carty and his associates. They were determined that the glory of spanning the Atlantic by wireless telephone should come to America and American engineers. They wanted history to record the wireless telephone as an American achievement along with the telegraph and the telephone. The methods used in achieving the wireless telephone were widely different from those which brought forth the telegraph and the telephone. Times had changed. Men had found that it was more effective to work together through organizations than to struggle along as individuals. The very physical scope of the undertakings made the old methods impracticable. One cannot perfect a transcontinental telephone line nor a transatlantic wireless telephone in a garret. And with a powerful organization behind them it was not necessary for Carty and his associates to starve and skimp through interminable years, handicapped by the inadequate equipment, while they slowly achieved results. This great organization, working with modern methods, produced the most wonderful results with startling rapidity. Important work had already been done by Marconi, Fessenden, De Forest, and others. But their results were still incomplete; they could not talk for any considerable distance. Carty organized his staff with care, Bancroft Gerhardi, Doctor Jewett, H.D. Arnold, and Colpitts being prominent among the group of brilliant American scientists who joined with Carty in his great undertaking. While much had been accomplished, much still remained to be done, and the various contributions had to be co-ordinated into a unified, workable whole. In large part it was Carty's task to direct the work of this staff and to see that all moved smoothly and in the right direction. Just as the telephone was more complex than the telegraph, and the wireless telegraph than the telephone, so the apparatus used in wireless telephony is even more complex and technical. Working with the intricate mechanisms and delicate apparatus, one part after another was improved and adapted to the task at hand. To the devices of Carty and his associates was added the extremely delicate detector that was needed. This was the invention of Dr. Lee de Forest, an American inventor and a graduate of the Sheffield Technical School of Yale University. De Forest's contribution was a lamp instrument, a three-step audion amplifier. This is to the wireless telephone what the coherer is to the wireless telegraph. It is so delicate that the faintest currents coming through the ether will stimulate it and serve to set in motion local sources of electrical energy so that the waves received are magnified to a point where they will produce sound. By the spring of 1915, but a few months after the transcontinental telephone line had been put in operation, Carty had his wireless telephone apparatus ready for extended tests. A small experimental tower was set up at Montauk Point, Long Island, and another was borrowed at Wilmington, Delaware. The tests were successful, and the experimenters found that they could talk freely with each other. Soon they talked over a thousand miles, from the tower at Montauk Point to another at St. Simon's Island, Georgia. This in itself was a great achievement, but the world was not told of it. "Do it first and then talk about it" is the maxim with Theodore Vail and his telephone men. This was but a beginning, and Carty had far more wonderful things in mind. It was on the 29th of September, 1915, that Carty conducted the demonstrations which thrilled the world and showed that wireless telephony was an accomplished fact. Sitting in his office in New York, President Theodore Vail spoke into his desk telephone of the familiar type. The wires carried his words to the towers of the Navy wireless station at Arlington, Virginia, where they were delivered to the sending apparatus of the wireless telephone. Leaping into space, they traveled in every direction through the ether. The antenna of the wireless station at Mare Island, California, caught part of the waves and they were amplified so that John Carty, sitting with his ear to the receiver, could hear the voice of his chief. Carty and his associates had not only developed a system which made it possible to talk across the continent without wires, but they had made it possible to combine wire and wireless telegraphy. He and Vail talked with each other freely and easily, while the naval officers who verified the tests marveled. But even more wonderful things were to come. Early in the morning of the next day other messages were sent from the Arlington tower, and these messages were heard by Lloyd Espenschied, one of Carty's engineers, who was stationed at the wireless station at Pearl Harbor, near Honolulu, Hawaii. The distance covered was nearly five thousand miles, and half of it was across land, which is the more remarkable as the wireless does not operate so readily over land as over water. The distance covered in this test was greater than the distance from Washington to London, Paris, Berlin, Vienna, or Petrograd. The successful completion of this test meant that the capitals of the great nations of the world might communicate, might talk with one another, by wireless telephone. Only a receiving set had been installed at Hawaii, so that it was not possible for Espenschied to reply to the message from Arlington, and it was not until his message came by cable that those at Arlington knew that the words they had spoken had traveled five thousand miles. Other receiving sets had been located at San Diego and at Darien on the Isthmus of Panama, and at these points also the words were distinctly heard. By the latter part of October all was in readiness for a transatlantic test, and on the 20th of October American engineers, with American apparatus installed at the great French station at the Eiffel Tower, Paris, heard the words spoken at Arlington, Virginia. Carty and his engineers had bridged the Atlantic for the spoken word. Because of war-time conditions it was not possible to secure the use of the French station for an extended test, but the fact was established that once the apparatus is in place telephonic communication between Europe and America may he carried on regularly. The apparatus used as developed by the engineers of the Bell system was in a measure an outgrowth of their work with the long-distance telephone. Wireless telephony, despite the wonders it has already accomplished, is still in its infancy. With more perfect apparatus and the knowledge that comes with experience we may expect that speech will girdle the earth. It is natural that one should wonder whether the wireless telephone is destined to displace our present apparatus. This does not seem at all probable. In the first place, wireless telephony is now, and probably always will be, very expensive. Where the wire will do it is the more economical. There are many limitations to the use of the other for talking purposes, and it cannot be drawn upon too strongly by the man of science. It will accomplish miracles, but must not be overtaxed. Millions of messages going in all directions, crossing and recrossing one another, as is done every day by wire, are probably an impossibility by wireless telephony. Weird and little-understood conditions of the ether, static electricity, radio disturbances, make wireless work uncertain, and such a thing as twenty-four-hour service, seven days in the week, can probably never be guaranteed. In radio communication all must use a common medium, and as its use increases, so also do the difficulties. The privacy of the wire is also lacking with the wireless telephone. But because a way was found to couple the wireless telephone with the wire telephone, the new wonder has great possibilities as a supplement to our existing system. Before so very long it may be possible for an American business man sitting in his office to call up and converse with a friend on a liner crossing the Atlantic. The advantages of speaking between ship and ship as an improvement over wireless telegraphy in time of need are obvious. A demonstration of the part this great national telephone system would play in the country's defense in case of attack was held in May of 1916. The Navy Department at Washington was placed in communication with every navy-yard and post in the United States, so that the executive officers could instantly talk with those in charge of the posts throughout the country. The wireless telephone was used in addition to the long distance, and Secretary of the Navy Daniels, sitting at his desk at Washington, talked with Captain Chandler, who was at his station on the bridge of the U.S.S. _New Hampshire_ at Hampton Roads. Whatever the future limitations of wireless telephony, there is no doubt as to the place it will take among the scientific accomplishments of the age. Merely as a scientific discovery or invention, it ranks among the wonders of civilization. Much as the tremendous leap of human voice across the line from New York to San Francisco appealed to the mind, there is something infinitely more fascinating in this new triumph of the engineer. The human mind can grasp the idea of the spoken word being carried along wires, though that is difficult enough, but when we try to understand its flight through space we are faced with something beyond the comprehension of the layman and almost past belief. We have seen how communication has developed, very slowly at first, and then, as electricity was discovered, with great rapidity until man may converse with man at a distance of five thousand miles. What the future will bring forth we do not know. The ether may be made to accomplish even more wonderful things as a bearer of intelligence. Though we cannot now see how it would be possible, the day may come when every automobile and aeroplane will be equipped with its wireless telephone, and the motorist and aviator, wherever they go, may talk with anyone anywhere. The transmission of power by wireless is confidently predicted. Pictures have been transmitted by telegraph. It may be possible to transmit them by wireless. Then some one may find out how to transmit moving pictures through the ether. Then one might sit and see before him on a screen a representation of what was then happening thousands of miles away, and, listening through a telephone, hear all the sounds at the same place. Wonders that we cannot even now imagine may lie before us. APPENDIX A NEW DEVELOPMENTS OF THE TELEGRAPH _By F.W. Lienan, Superintendent Tariff Bureau, Western Union Telegraph Company_ The invention of Samuel F.B. Morse is unique in this, that the methods and instruments of telegraph operation as he evolved them from his first experimental apparatus were so simple, and yet so completely met the requirements, that they have continued in use to the present day in practically their original form. But this does not mean that there has not been the same constant striving for betterment in this as in every other art. Many minds have, since the birth of the telegraph, occupied themselves with the problem of devising improved means of telegraphic transmission. The results have varied according to the point of view from which the subject was approached, but all, directly or indirectly, sought the same goal (the obvious one, since speed is the essence of telegraphy), to find the best means of sending more messages over the wire in a given time. It will readily suggest itself that the solution of this problem lies either in an arrangement enabling the wire to carry more than one message at once, or in some apparatus capable of transmitting messages over the wire more rapidly than can be done by hand, or in a combination of both these principles. Duplex and quadruples operations are perhaps the most generally known methods by which increased utilization of the capacity of the line has been achieved. Duplex operation permits of the sending of two messages over one wire in opposite directions at the same time; and quadruples, the simultaneous transmission of four messages, two going in each direction. Truly a remarkable accomplishment; but, like many other things that have found their permanent place in daily use, become so familiar that we no longer pause to marvel at it. These expedients constitute a direct and very effective attack on the problem how to get more work out of the wire with the existing means of operation, and on account of their fundamental character and the important place which by reason thereof they have taken in the telegraphic art, are entitled to first mention. The problem of increasing the rapidity of transmission has been met by various automatic systems of telegraphy, so called because they embody the idea of mechanical transmission with resulting gain in speed and other advantages. The number of these which have from time to time been devised is considerable. Not all have proven to be practicable, but those which have failed to prove in under actual operating conditions none the less display evidence of ingenuity which may well excite our admiration. To mention one or two which may be interesting on account of the oddity of their method--there was, for instance, an early device, similar in principle to the calling apparatus of the automatic telephone, which involved the turning of a movable disk so that a projection on its circumference pointed successively to the letters to be transmitted. Experiments were made with ordinary metal type set up in a composing-stick, a series of brushes passing over the type faces and producing similar characters on a tape at the other end of the line. In another more recent ingenious device a pivoted mirror at the receiving end was so manipulated by the electrical impulses that a ray of light reflected from the surface of the mirror actually wrote the message upon sensitized paper, like a pencil, in a fair handwriting. In another the receiving apparatus printed vertical, horizontal, and slanting lines in such manner that they combined to make letters, rather angular, it is true, but legible. These and other kindred devices are interesting as efforts to accomplish the direct production of legible messages. In experimental tests they performed their function successfully, and in some cases with considerable speed, but some of them required more than one line wire, some were too sensitive to disturbance by inductive currents and some developed other weaknesses which have prevented their incorporation in the actual operating machinery of to-day. In the general development of the so-called automatic telegraph devices which have been or now are in practical operation, two lines have been pursued. One involves direct keyboard transmission; the other, the use at the sending end of a perforated tape capable of being run through a transmitting machine at high speed. One type of the former is the so-called step-by-step process, in which a revolving body in the transmitting apparatus, as, for instance, a cylinder provided with pegs placed at intervals around its circumference in spiral fashion, is arrested by the depression of the keys of the keyboard in such a way that a type wheel in the receiving apparatus at the distant end of the line prints the corresponding letter. This method was employed in the House and Phelps printing telegraphs operated by the Western Union Telegraph Company in its earlier days, and is to-day used in the operation of the familiar ticker. In another type of direct keyboard operation the manipulation of the keys transmits the impulses directly to the line and the receiving apparatus translates them by electrically controlled mechanical devices into printed characters in message form. The systems best adapted to rapid telegraph work are predicated on the use of a perforated tape on which, by means of a suitable perforating apparatus, little round holes are produced in various groupings, each group, when the tape is passed through the transmitter, causing a certain combination of electrical impulses to pass over the wire. The transmitter as a rule consists of a mechanically or motor driven mechanism which causes the telegraph impulses to be transmitted to the line, and the combination and character of the impulses are determined by the tape perforations. The rapidity with which the tape may be driven through the transmitter makes very high speed operation possible. Of course it is necessary that there should be at the other end of the wire apparatus capable of receiving and recording the signals as speedily as they are sent. As early as 1848 Alexander Bain perfected a system involving the use of the perforated transmitting tape; at the receiving station the messages were recorded in dots and dashes upon a chemically prepared strip of paper by means of iron pens, the metal of which was, through the combined action of the electrical current and the chemical preparation, decomposed, producing black marks in the form of dots and dashes upon the paper. The Bain apparatus was in actual operation in the younger days of the telegraph. Various systems, based on similar principles, involving tape transmission and the production of dots and dashes on a receiving tape, have from time to time been devised, but have generally not succeeded in establishing any permanent usefulness in competition with more effective instrumentalities which have been perfected. The hardiest survivor of them is the Wheatstone apparatus, which has been in successful operation for years. Originally the perforating--or, to use the commonly current term, the punching--of the Wheatstone sending tape was accomplished by a mechanism equipped with three keys--one for the dot, one for the dash, and one for the space. The keys were struck with rubber-tipped mallets held in the hands of the operator and brought down with considerable force. Later this rather primitive perforator was supplanted by one equipped with a full keyboard on the order of a typewriter keyboard. At the receiving end of the line the messages are produced on a tape in dots and dashes of the Morse alphabet, and hence a further process of translation is necessary. This system has proven very useful, particularly in times of wire trouble and scarcity of facilities, when it is essential to move as many messages as possible over the available lines. The schemes devised for combining automatic transmission by the perforated-tape method with direct production of the message at its destination in ordinary letters and figures, eliminating the intervening step of translation from Morse characters, have been many. Their individual enumeration is beyond the scope of the present discussion, and would in any event involve a wearisome exposition of their distinguishing technical features. Several of these systems are at present in practical and very effective operation. One of the forerunners of the printing telegraph systems now in use was the Buckingham system, for many years employed by the Western Union Telegraph Company, but now for some time obsolete. The receiving mechanism of this system printed the messages on telegraph blanks placed upon a cylinder of just the right circumference to accommodate two telegraph blanks. The blanks were arranged in pairs, rolled into the form of a tube and placed around the cylinder. When two messages had been written a new pair of blanks had to be substituted. This was a rather awkward arrangement, but at a time when more highly developed apparatus had not been perfected it served its purpose to good advantage. The printing telegraphs of to-day produce their messages by the direct operation of typewriting machines or mechanisms operating substantially in the same manner as the ordinary typewriting machine. The methods by which the electrical impulses coming over the line are transformed into mechanical operation of the typewriter keys, or what corresponds to the typewriter keys, vary. It would be difficult to describe how this function is performed without entering upon much detail of a highly technical character. Suffice it to say that means have been devised by which each combination of electrical impulses coming over the line wire causes a channel to be opened for the motor operation of the typewriting key-bar operating the corresponding letter upon the typewriter apparatus. These machines write the messages with proper arrangement of the date line, address, text, and signature, operating not only the type, but also the carriage shift and the line spacing as required. A further step in advance has been made by feeding the blanks into the receiving typewriter from a continuous roll, an attendant tearing the messages off as they are completed. The entire operation is automatic from beginning to end and capable of considerable speed. There remained the problem of devising some means by which a number of automatic units could be operated over the same line at the same time. This is not by any means a new proposition. Here again various solutions have been offered by the scientists both of Europe and of this country, and different systems designed to accomplish the desired object have been placed in operation. One of the most recent, and we believe the most efficient so far developed, is the so-called multiplex printer system, devised by the engineers of the Western Union Telegraph Company and now being extensively used by that company. Perhaps the best picture of what is accomplished by this system can be given by an illustration. Let us assume a single wire between New York and Chicago. At the New York end there are connected with this wire four combined perforators and transmitters, and four receiving machines operating on the typewriter principle. At the Chicago end the wire is connected with a like number of sending and receiving machines. All these machines are in simultaneous operation; that is to say, four messages are being sent from New York to Chicago, and four messages are being sent from Chicago to New York, all at the same time and over a single wire, and the entire process is automatic. The method by which eight messages can be sent over a single wire at the same time without interfering with one another cannot readily be described in simple terms. It may give some comprehension of the underlying principle to say that the heart of the mechanism is in two disks at each end of the line, which are divided into groups of segments insulated from each other, each group being connected to one of the sending or receiving machines, respectively. A rotating contact brush connected to the line wire passes over the disk, so that, as it comes into contact with each segment, the line wire is connected in turn with the channel leading to the corresponding operating unit. The brushes revolve in absolute unison of time and position. To use the same illustration as before, the brush on the Chicago disk and the brush on the New York disk not only move at exactly the same speed, but at any given moment the two brushes are in exactly the same position with regard to the respective group of segments of both disks. If we now conceive of these brushes passing over the successive segments of the disks at a very great rate of speed, it may be understood that the effect is that the electrical impulses are distributed, each receiving machine receiving only those produced by the corresponding sending machine at the other end. In other words, each of the sets of receiving and sending apparatus really gets the use of the line for a fraction of the time during each revolution of the brushes of the distributer or disk mechanism. The multiplex automatic circuits are being extended all over the country and are proving extremely valuable in handling the constantly growing volume of telegraph traffic. What has thus been achieved in developing the technical side of telegraph operation must be attributed in part to that impulse toward improvement which is constantly at work everywhere and is the most potent factor in the progress of all industries, but in large measure it is the reflex of the growing--and recently very rapidly growing--demands which are made upon the telegraph service. Emphasis is placed on the larger ratio of growth in this demand in recent years because it is peculiarly symptomatic of a noticeably wider realization of the advantages which the telegraph offers as an effective medium for business and social correspondence than has heretofore been in evidence. It means that we have graduated from that state of mind which saw in the telegraph something to be resorted to only under the stress of emergency, which caused many good people to associate a telegram with trouble and bad news and sudden calamity. There are still some dear old ladies who, on receipt of a telegram, make a rapid mental survey of the entire roster of their near and distant relatives and wonder whose death or illness the message may announce before they open the fateful envelope, only to find that up-to-date Cousin Mary, who has learned that the telegraph is as readily used as the mail and many times more rapid and efficient, wants to know whether they can come out for the week-end. When Cousin Mary of to-day wants to know, she wants to know right away--not only that she has her arrangements to make, but also because she just does not propose to wait a day or two to get a simple answer to a simple question. Therein she embodies the spirit of the times. Our ancestors were content to jog along for days in a stuffy stage-coach; we complain that the train which accomplishes the same distance in a few hours is too slow. We act more quickly; we think more quickly. We have to if we want to keep within earshot of the band. This speeding up makes itself quite obviously most apparent in our business processes. No body of business men need be told how much keener competition is becoming daily, how much narrower the margin by which success must be won. Familiar phrases, these. But behind them lies a wealth of tragedy. How many have fallen by the way? It is estimated that something less than ten per cent. of those who engage in business on their own account succeed. How terrible the percentage of those who fail! The race has become too swift for them. Driven by the lash of competition, business must perforce move faster and faster. Time is becoming ever more precious. Negotiations must be rapidly conducted, decisions arrived at quickly, transactions closed on the moment. What wonder that all this makes for a vastly increased use of the quickest method of communication? That is but one of the conditions which accounts for the growing use of the telegraph. Another is to be found in the recognition of the convenience of the night letter and day letter. This has brought about a considerable increase in the volume of family and social correspondence by telegraph, which will grow to very much greater proportions as experience demonstrates its value. In business life the night letter and day letter have likewise established a distinct place for themselves. Here also the present development of this traffic can be regarded as only rudimentary in comparison with the possibilities of its future development, indications of which are already apparent. It has been discovered that the telegram, on account of its peculiar attention-compelling quality, is an effective medium not only for the individual appeal, but for placing business propositions before a number of people at once, the night letters and day letters being particularly adapted to this purpose by reason of the greater scope of expression which they offer. Again, business men are developing the habit of using the telegram in keeping in touch with their field forces and their salesmen and encouraging their activities, in cultivating closer contact with their customers, in placing their orders, in replenishing their stocks, and in any number of other ways calculated to further the profitable conduct of their enterprises. All this means that the telegraph is increasingly being utilized as a means of correspondence of every conceivable sort. It means also that with the growing appreciation of its adaptability to the every-day needs of social and business communication a very much larger public demand upon it must be anticipated, and it is to meet this demand with prompt and satisfactory service that the telegraph company has been bending its efforts to the perfection of a highly developed organization and of operating appliances of the most modern and efficient type. APPENDIX B Through the courtesy of J.J. Carty, Esq., Chief Engineer of the American Telephone and Telegraph Company, there follows the clean-cut survey of the evolution of the telephone presented in his address before the Franklin Institute in Philadelphia, May 17, 1916, when he received the gold medal of the Institute. More than any other, the telephone art is a product of American institutions and reflects the genius of our people. The story of its wonderful development is a story of our own country. It is a story exclusively of American enterprise and American progress, for, although the most powerful governments of Europe have devoted their energies to the development and operation of telephone systems, great contributions to the art have not been made by any of them. With very few exceptions, the best that is used in telephony everywhere in the world to-day has been contributed by workers here in America. It is of peculiar interest to recall the fact that the first words ever transmitted by the electric telephone were spoken in a building at Boston, not far from where Benjamin Franklin first saw the light. The telephone, as well as Franklin, was born at Boston, and, like Franklin, its first journey into the world brought it to Philadelphia, where it was exhibited by its inventor, Alexander Graham Bell, at the Centennial Exhibition in 1876, held here to commemorate the first hundred years of our existence as a free and independent nation. It was a fitting contribution to American progress, representing the highest product of American inventive genius, and a worthy continuance of the labors of Franklin, one of the founders of the science of electricity as well as of the Republic. Nothing could appeal more to the genius of Franklin than the telephone, for not only have his countrymen built upon it an electrical system of communication of transcendent magnitude and usefulness, but they have made it into a powerful agency for the advancement of civilization, eliminating barriers to speech, binding together our people into one nation, and now reaching out to the uttermost limits of the earth, with the grand aim of some day bringing together the people of all the nations of the earth into one common brotherhood. On the tenth day of March, 1876, the telephone art was born, when, over a wire extending between two rooms on the top floor of a building in Boston, Alexander Graham Bell spoke to his associate, Thomas A. Watson, saying: "Mr. Watson, please come here. I want you." These words, then heard by Mr. Watson in the instrument at his ear, constitute the first sentence ever received by the electric telephone. The instrument into which Doctor Bell spoke was a crude apparatus, and the current which it generated was so feeble that, although the line was about a hundred feet in length, the voice heard in the receiver was so faint as to be audible only to such a trained and sensitive ear as that of the young Mr. Watson, and then only when all surrounding noises were excluded. Following the instructions given by Doctor Bell, Mr. Watson with his own hands had constructed the first telephone instruments and ran the first telephone wire. At that time all the knowledge of the telephone art was possessed exclusively by those two men. There was no experience to guide and no tradition to follow. The founders of the telephone, with remarkable foresight, recognized that success depended upon the highest scientific knowledge and technical skill, and at once organized an experimental and research department. They also sought the aid of university professors eminent for their scientific attainments, although at that time there was no university giving the degree of Electrical Engineer or teaching electrical engineering. From this small beginning there has been developed the present engineering, experimental and research department which is under my charge. From only two men in 1876 this staff has, in 1915, grown to more than six hundred engineers and scientists, including former professors, post-graduate students, and scientific investigators, graduates of nearly a hundred American colleges and universities, thus emphasizing in a special way the American character of the art. The above number includes only those devoted to experimental and research work and engineering development and standardization, and does not include the very much larger body of engineers engaged in manufacturing and in practical field work throughout the United States. Not even the largest and most powerful government telephone and telegraph administration of Europe has a staff to be compared with this. It is in our great universities that anything like it is to be found, but even here we find that it exceeds in number the entire teaching staff of even our largest technical institutions. A good idea may spring up in the mind of man anywhere, but as applied to such a complex entity as a telephone system, the countless parts of which cover a continent, no individual unaided can bring the idea to a successful conclusion. A comprehensive and effective engineering and scientific and development organization such as this is necessary, and years of expensive work are required before the idea can be rendered useful to the public. But, vital as they are to its success, the, telephone art requires more than engineers and scientists. So we find that in the building and operation and maintenance of that vast continental telephone system which bears the name of Bell, in honor of the great inventor, there are at work each day more than 170,000 employees, of which nearly 20,000 are engaged in the manufacture of telephones, switchboards, cables, and all of the thousands and tens of thousands of parts required for the operation of the telephone system of America. The remaining 150,000 are distributed throughout all of the States of the Union. About 80,000 of these are women, largely telephone operators; 50,000 are linemen, installers, cable splicers, and the like, engaged in the building and maintaining of the continental plant. There are thousands of other employees in the accounting, legal, commercial and other departments. There are 2,100 engineers located in different parts of the country. The majority of these engineers have received technical training in American technical schools, colleges, and universities. This number does not include by any means all of those in the other departments who have received technical or college training. In view of the technical and scientific nature of the telephone art, an unusually high-grade personnel is required in all departments, and the amount of unskilled labor employed is relatively very small. No other art calls forth in a higher degree those qualities of initiative, judgment, skill, enterprise, and high character which have in all times distinguished the great achievements of America. In 1876 the telephone plant of the whole world could be carried away in the arms of one man. It consisted of two crude telephones like the one now before you, connected together by a wire of about one hundred feet in length. A piece cut from this wire by Mr. Watson himself is here in this little glass case. At this time there was no practical telephone transmitter, no hard-drawn copper wire, no transposed and balanced metallic circuits, no multiple telephone switchboard, or telephone switchboard of any kind, no telephone cable that would work satisfactorily; in fact, there were none of the multitude of parts which now constitute the telephone system. The first practical telephone line was a copy of the best telegraph line of the day. A line wire was strung on the poles and housetops, using the ground for the return circuit. Electrical disturbances, coming from no one knows where, were picked up by this line. Frequently the disturbances were so loud in the telephone as to destroy conversation. When a second telephone line was strung alongside the first, even though perfectly insulated, another surprise awaited the telephone pioneers. Conversation carried on over one of these wires could plainly be heard on the other. Another strange thing was discovered. Iron wire was not so good a conductor for the telephone current as it was for the telegraph current. The talking distance, therefore, was limited by the imperfect carrying power of the conductor and by the confusing effect of all sorts of disturbing currents from the atmosphere and from neighboring telephone and telegraph wires. These and a multitude of other difficulties, constituting problems of the most intricate nature, impeded the progress of the telephone art, but American engineers, by persistent study, incessant experimentation, and the expenditure of immense sums of money, have overcome these difficulties. They have created a new art, inventing, developing, and perfecting, making improvements great and small in telephone, transmitter, line, cable, switchboard, and every other piece of apparatus and plant required for the transmission of speech. As the result of nearly forty years of this unceasing, organized effort, on the 25th of January, 1915, there was dedicated to the service of the American public a transcontinental telephone line, 3,600 miles long, joining the Atlantic and the Pacific, and carrying the human voice instantly and distinctly between San Francisco and New York and Philadelphia and Boston. On that day over this line Doctor Bell again talked to Mr. Watson, who was now 3,400 miles away. It was a day of romantic triumph for these two men and for their associates and their thousands of successors who have built up the great American telephone art. The 11th of February following was another day of triumph for the telephone art as a product of American institutions, for, in the presence of dignitaries of the city and State here at Philadelphia and at San Francisco, the sound of the Liberty Bell, which had not been heard since it tolled for the death of Chief-Justice Marshall, was transmitted by telephone over the transcontinental line to San Francisco, where it was plainly heard by all those there assembled. Immediately after this the stirring tones of the "Star-spangled Banner" played on the bugle at San Francisco were sent like lightning back across the continent to salute the old bell in Philadelphia. It had often been pointed out that the words of the tenth verse of the twenty-fifth chapter of Leviticus, added when the bell was recast in 1753, were peculiarly applicable to the part played by the old bell in 1776. But the words were still more prophetic. The old bell had been silent for nearly eighty years, and it was thought forever, but by the use of the telephone a gentle tap, which could be heard through the air only a few feet away, was enough to transmit the tones of the historic relic all the way across the continent from the Atlantic to the Pacific. Thus, by the aid of the telephone art, the Liberty Bell was enabled literally to fulfil its destiny and "Proclaim liberty throughout all the land, unto all the inhabitants thereof." The two telephone instruments of 1876 had become many millions by 1916, and the first telephone line, a hundred feet long, had grown to one of more than three thousand miles in length. This line is but part of the American telephone system of twenty-one million miles of wire, connecting more than nine million telephone stations located everywhere throughout the United States, and giving telephone service to one hundred million people. Universal telephone service throughout the length and breadth of our land, that grand objective of Theodore N. Vail, has been attained. While Alexander Graham Bell was the first to transmit the tones of the human voice over a wire by electricity, he was also the first to transmit the tones of the human voice by the wireless telephone, for in 1880 he spoke along a beam of light to a point a considerable distance away. While the method then used is different from that now in vogue, the medium employed for the transmission is the same--the ether, that mysterious, invisible, imponderable wave-conductor which permeates all creation. While many great advances in the wireless art were made by Marconi and many other scientists in America and elsewhere, it remained for that distinguished group of American scientists and engineers working under my charge to be the first to transmit the tones of the human voice in the form of intelligible speech across the Atlantic Ocean. This great event and those immediately preceding it are so fresh in the public mind that I will make but a brief reference to them here. On April 4, 1915, we were successful in transmitting speech without the use of wires from our radio station at Montauk Point on Long Island to Wilmington, Delaware. On May 18th we talked by radio telephone from our station on Long Island to St. Simon Island in the Atlantic Ocean, off the coast of Georgia. On the 27th of August, with our apparatus installed by permission of the Navy Department at the Arlington, Virginia, radio station, speech was successfully transmitted from that station to the Navy wireless station equipped with our receiving apparatus at the Isthmus of Panama. On September 29th, speech was successfully transmitted by wire from New York City to the radio station at Arlington, Virginia, and thence by wireless telephone across the continent to the radio station at Mare Island Navy-yard, California, where I heard and understood the words of Mr. Theodore N. Vail speaking to me from the telephone on his desk at New York. On the next morning at about one o'clock, Washington time, we established wireless telephone communication between Arlington, Virginia, and Pearl Harbor in the Hawaiian Islands, where an engineer of our staff, together with United States naval officers, distinctly heard words spoken into the telephone at Arlington, Virginia. On October 22d, from the Arlington tower in Virginia, we successfully transmitted speech across the Atlantic Ocean to the Eiffel Tower at Paris, where two of our engineers, in company with French military officers, heard and understood the words spoken at Arlington. On the same day when speech was being transmitted by the apparatus at Arlington to our engineers and to the French military officers at the Eiffel Tower in Paris, our telephone engineer at Pearl Harbor, Hawaii, together with an officer of the United States Navy, heard the words spoken from Arlington to Paris and recognized the voice of the speaker. As a result of exhaustive researches, too extensive to describe here, it has been ascertained that the function of the wireless telephone is not to do away with the use of wires, but rather to be employed in situations where wires are not available or practicable, such as between ship and ship, and ship and shore, and across large bodies of water. The ether is a universal conductor for wireless telephone and telegraph impulses and must be used in common by all who wish to employ those agencies of communication. In the case of the wireless telegraph the number of messages which may be sent simultaneously is much restricted. In the case of the wireless telephone, owing to the thousands of separate wave-lengths required for the transmission of speech, the number of telephone conversations which may be carried on at the same time is still further restricted and is so small that all who can employ wires will find it necessary to do so, leaving the ether available for those who have no other means of communication. This quality of the ether which thus restricts its use is really a characteristic of the greatest value to mankind, for it forms a universal party line, so to speak, connecting together all creation, so that anybody anywhere, who connects with it in the proper manner, may be heard by every one else so connected. Thus, a sinking ship or a human being anywhere can send forth a cry for help which may be heard and answered. No one can tell how far away are the limits of the telephone art, I am certain that they are not to be found here upon the earth, for I firmly believe in the fulfilment of that prophetic aspiration expressed by Theodore N. Vail at a great gathering in Washington, that some day we will build up a world telephone system, making necessary to all peoples the use of a common language or a common understanding of languages which will join all of the people of the earth into one brotherhood. I believe that the time will come when the historic bell which now rests in Independence Hall will again be sounded, and that by means of the telephone art, which to-day has received such distinguished recognition at your hands, it will proclaim liberty once more, but this time throughout the whole world unto all the inhabitants thereof. And, when this world is ready for the message, I believe the telephone art will provide the means for transmitting to all mankind a great voice saying, "Peace on earth, good will toward men." INDEX A Ampere's telegraph, 42. Anglo-American Telegraph Co., 134. Ardois signal system, 30. Atlantic cable projected, 109; attempted, 117, 121, 123, 133; completed, 124, 136. Audion amplifier, 256. Automatic telegraphy, 53, 105, 266. B Baltimore-Washington Telegraph Line, 86. Bell, Alexander Graham, parentage, 140; youth, 141; teaches elocution, 146; experiments with speech, 151, 161; meets Henry, 158; invents telephone, 162; at Centennial Exposition, 165; demonstrates telephone, 170; Bell Telephone Association, 178; Bell-Western Union Settlement; Bell and wireless telegraphy, 189; Transcontinental telephone, 248. Bethell, Union N., 241. Blake, Clarence J., 154. Blake, Francis, invents telephone transmitter, 182. Branly coherer, 204. Brett, J.W., 112. Bright, Charles Tiltson, 112, 120, 125, 128. C Cable laid across Channel, 108. Carty, J.J., youth, 232; enters telephone field, 234; Carty and the switchboard, 235, 242; uses metallic circuit, 238; in New York City, 241; invents bridging bell, 243; chief engineer, 244; extends long-distance telephone, 246; seeks wireless telephone, 253; talks across continent by wireless, 257. Clepsydra, 18. Code flags at sea, 24. Coherer, 203. Colomb's flashing lights, 25. Congress votes funds for telegraph, 84. Cooke, William P., 49, 52. Cornell, Ezra, 86, 93, 107. D Davy's needle telegraph, 44. De Forest, Dr. Lee, 225, 256. Dolbear and telephone, 185; wireless telegraphy, 194. Drawbaugh case, 186. Duplex telegraphy, 104, 265. Dyar, Harrison Gray, 41. E Edison, and the telegraph, 104; telephone transmitter 180; wireless telegraphy, 195. Ellsworth, Annie, 85. F Field, Cyrus W., plans Transatlantic cable, 110; honors, 125, 136; develops cable, 130, 134. G Gale, Professor, 67, 86. Gauss and Weber's telegraph, 43. Gisborne, F.N., 109. Gray, Elisha, 157, 184. _Great Eastern_, 132, 135, 139. Guns as marine signals, 23. H Hammond, John Hays, 229. Heaviside, A.W., 196. Heliograph, 29. Henry, Joseph, 65, 67, 158, 169. Hertz and the Hertzian waves, 197. Hubbard, Gardiner G., 149, 159, 170, 178. Hubbard, Mabel, 148, 166. I Indian smoke signals, 20. J Jackson, Dr. Charles T., 64, 79. K Kelvin, Lord (See Thomson), 138. "Kwaker" captured, 50. L Long-distance telephone, 245. M Magnetic Telegraph Co., 93. Marconi, boyhood, 199; accomplished wireless telegraphy, 202; demonstration in England, 209; Transatlantic telegraphy, 217; Marconi Telegraph Company, 220. Marine signals on Argonautic expedition, 15. Mirror galvanometer, 127. Mirrors of Pharaoh, 17. Morse at University of New York, 66. Morse, code in signals, 27; parentage, 56; at Yale, 57; art student, 59; artist, 62; conceives the telegraph, 63; exhibits telegraph, 75; offers telegraph to Congress, 76, 91; patents telegraph, 82; submarine cable, 83, 107; erects first line, 86; dies, 104. Multiplex printer telegraph, 274. Mundy, Arthur J., 31. O O'Reilly, Henry, 94. P Preece, W.H., 196, 209. Printing telegraph, 271. Pupin, Michael I., 247. Q Quadruplex telegraphy, 104, 265. R Reis's musical telegraph, 157. S Sanders, Thomas, 148, 159, 178. Scribner, Charles E., 236. Searchlight telephone, 251. Semaphore signals, 27. Shouting sentinels, 16. Sibley, Hiram, 96, 99. Signal columns, 19. Siphon recorder, 137. Smith, Francis O.J., 76. Stentorophonic tube, 18. Submarine signals, 31. T Telegraph, first suggestion, 39; patented, 82; development, 264. Telephone invented and patented, 162; at Centennial, 165; exchange, 177. Thomson, youth, 144; cable adviser, 121; invents mirror galvanometer, 126; knighted, 136; invents siphon recorder, 137; connection with telephone, 169. Transatlantic cable (See Atlantic cable). Transatlantic wireless telegraphy, 216. Transatlantic wireless telephone, 259. Transcontinental telegraph, 96. Transcontinental telephone, 246. Transcontinental wireless telephone, 257. Trowbridge, John, 190. Troy, signaling fall of, 14. Tuning the wireless telegraph, 222. V Vail, Alfred, arranges Morse code, joins Morse, 70; makes telephone apparatus, 72; operates first line, 90; improves telegraph, 100. Vail, Theodore, joins telephone forces, 180; puts wires underground, 239; adopts copper circuits, 240; resumes telephone leadership, 244; talks across continent without wires, 257. W Watson, aids Bell with telephone, 159; telephone partner, 175; helps demonstrate telephone, 175; telephones across continent, 248. Western Union, organized, 96; enters telephone field, 178. Wheatstone, 1; boyhood, 45; five-needle telegraph, 49; single-needle telegraph, 52; Wheatstone-Cooke controversy, 52; automatic transmitter, 53; bridge, 53; opposes Morse, 78; encourages Bell, 145. Wig-wag system, 26. Wireless telegraphy suggested, 188; invented, 202; on shipboard, 221; in the future, 230. Wireless telephone, conceived, 250; future, 260; in navy, 261. 
819	----	THE HISTORY OF THE TELEPHONE By Herbert N. Casson PREFACE Thirty-five short years, and presto! the newborn art of telephony is fullgrown. Three million telephones are now scattered abroad in foreign countries, and seven millions are massed here, in the land of its birth. So entirely has the telephone outgrown the ridicule with which, as many people can well remember, it was first received, that it is now in most places taken for granted, as though it were a part of the natural phenomena of this planet. It has so marvellously extended the facilities of conversation--that "art in which a man has all mankind for competitors"--that it is now an indispensable help to whoever would live the convenient life. The disadvantage of being deaf and dumb to all absent persons, which was universal in pre-telephonic days, has now happily been overcome; and I hope that this story of how and by whom it was done will be a welcome addition to American libraries. It is such a story as the telephone itself might tell, if it could speak with a voice of its own. It is not technical. It is not statistical. It is not exhaustive. It is so brief, in fact, that a second volume could readily be made by describing the careers of telephone leaders whose names I find have been omitted unintentionally from this book--such indispensable men, for instance, as William R. Driver, who has signed more telephone cheques and larger ones than any other man; Geo. S. Hibbard, Henry W. Pope, and W. D. Sargent, three veterans who know telephony in all its phases; George Y. Wallace, the last survivor of the Rocky Mountain pioneers; Jasper N. Keller, of Texas and New England; W. T. Gentry, the central figure of the Southeast, and the following presidents of telephone companies: Bernard E. Sunny, of Chicago; E. B. Field, of Denver; D. Leet Wilson, of Pittsburg; L. G. Richardson, of Indianapolis; Caspar E. Yost, of Omaha; James E. Caldwell, of Nashville; Thomas Sherwin, of Boston; Henry T. Scott, of San Francisco; H. J. Pettengill, of Dallas; Alonzo Burt, of Milwaukee; John Kilgour, of Cincinnati; and Chas. S. Gleed, of Kansas City. I am deeply indebted to most of these men for the information which is herewith presented; and also to such pioneers, now dead, as O. E. Madden, the first General Agent; Frank L. Pope, the noted electrical expert; C. H. Haskins, of Milwaukee; George F. Ladd, of San Francisco; and Geo. F. Durant, of St. Louis. H. N. C. PINE HILL, N. Y., June 1, 1910. CONTENTS CHAPTER I THE BIRTH OF THE TELEPHONE II THE BUILDING OF THE BUSINESS III THE HOLDING OF THE BUSINESS IV THE DEVELOPMENT OF THE ART V THE EXPANSION OF THE BUSINESS VI NOTABLE USERS OF THE TELEPHONE VII THE TELEPHONE AND NATIONAL EFFICIENCY VIII THE TELEPHONE IN FOREIGN COUNTRIES IX THE FUTURE OF THE TELEPHONE THE HISTORY OF THE TELEPHONE CHAPTER I. THE BIRTH OF THE TELEPHONE In that somewhat distant year 1875, when the telegraph and the Atlantic cable were the most wonderful things in the world, a tall young professor of elocution was desperately busy in a noisy machine-shop that stood in one of the narrow streets of Boston, not far from Scollay Square. It was a very hot afternoon in June, but the young professor had forgotten the heat and the grime of the workshop. He was wholly absorbed in the making of a nondescript machine, a sort of crude harmonica with a clock-spring reed, a magnet, and a wire. It was a most absurd toy in appearance. It was unlike any other thing that had ever been made in any country. The young professor had been toiling over it for three years and it had constantly baffled him, until, on this hot afternoon in June, 1875, he heard an almost inaudible sound--a faint TWANG--come from the machine itself. For an instant he was stunned. He had been expecting just such a sound for several months, but it came so suddenly as to give him the sensation of surprise. His eyes blazed with delight, and he sprang in a passion of eagerness to an adjoining room in which stood a young mechanic who was assisting him. "Snap that reed again, Watson," cried the apparently irrational young professor. There was one of the odd-looking machines in each room, so it appears, and the two were connected by an electric wire. Watson had snapped the reed on one of the machines and the professor had heard from the other machine exactly the same sound. It was no more than the gentle TWANG of a clock-spring; but it was the first time in the history of the world that a complete sound had been carried along a wire, reproduced perfectly at the other end, and heard by an expert in acoustics. That twang of the clock-spring was the first tiny cry of the newborn telephone, uttered in the clanging din of a machine-shop and happily heard by a man whose ear had been trained to recognize the strange voice of the little newcomer. There, amidst flying belts and jarring wheels, the baby telephone was born, as feeble and helpless as any other baby, and "with no language but a cry." The professor-inventor, who had thus rescued the tiny foundling of science, was a young Scottish American. His name, now known as widely as the telephone itself, was Alexander Graham Bell. He was a teacher of acoustics and a student of electricity, possibly the only man in his generation who was able to focus a knowledge of both subjects upon the problem of the telephone. To other men that exceedingly faint sound would have been as inaudible as silence itself; but to Bell it was a thunder-clap. It was a dream come true. It was an impossible thing which had in a flash become so easy that he could scarcely believe it. Here, without the use of a battery, with no more electric current than that made by a couple of magnets, all the waves of a sound had been carried along a wire and changed back to sound at the farther end. It was absurd. It was incredible. It was something which neither wire nor electricity had been known to do before. But it was true. No discovery has ever been less accidental. It was the last link of a long chain of discoveries. It was the result of a persistent and deliberate search. Already, for half a year or longer, Bell had known the correct theory of the telephone; but he had not realized that the feeble undulatory current generated by a magnet was strong enough for the transmission of speech. He had been taught to undervalue the incredible efficiency of electricity. Not only was Bell himself a teacher of the laws of speech, so highly skilled that he was an instructor in Boston University. His father, also, his two brothers, his uncle, and his grandfather had taught the laws of speech in the universities of Edinburgh, Dublin, and London. For three generations the Bells had been professors of the science of talking. They had even helped to create that science by several inven-tions. The first of them, Alexander Bell, had invented a system for the correction of stammering and similar defects of speech. The second, Alexander Melville Bell, was the dean of British elocutionists, a man of creative brain and a most impressive facility of rhetoric. He was the author of a dozen text-books on the art of speaking correctly, and also of a most ingenious sign-language which he called "Visible Speech." Every letter in the alphabet of this language represented a certain action of the lips and tongue; so that a new method was provided for those who wished to learn foreign languages or to speak their own language more correctly. And the third of these speech-improving Bells, the inventor of the telephone, inherited the peculiar genius of his fathers, both inventive and rhetorical, to such a degree that as a boy he had constructed an artificial skull, from gutta-percha and India rubber, which, when enlivened by a blast of air from a hand-bellows, would actually pronounce several words in an almost human manner. The third Bell, the only one of this remarkable family who concerns us at this time, was a young man, barely twenty-eight, at the time when his ear caught the first cry of the telephone. But he was already a man of some note on his own account. He had been educated in Edinburgh, the city of his birth, and in London; and had in one way and another picked up a smattering of anatomy, music, electricity, and telegraphy. Until he was sixteen years of age, he had read nothing but novels and poetry and romantic tales of Scottish heroes. Then he left home to become a teacher of elocution in various British schools, and by the time he was of age he had made several slight discoveries as to the nature of vowel-sounds. Shortly afterwards, he met in London two distinguished men, Alexander J. Ellis and Sir Charles Wheatstone, who did far more than they ever knew to forward Bell in the direction of the telephone. Ellis was the president of the London Philological Society. Also, he was the translator of the famous book on "The Sensations of Tone," written by Helmholtz, who, in the period from 1871 to 1894 made Berlin the world-centre for the study of the physical sciences. So it happened that when Bell ran to Ellis as a young enthusiast and told his experiments, Ellis informed him that Helmholtz had done the same things several years before and done them more completely. He brought Bell to his house and showed him what Helmholtz had done--how he had kept tuning-forks in vibration by the power of electro-magnets, and blended the tones of several tuning-forks together to produce the complex quality of the human voice. Now, Helmholtz had not been trying to invent a telephone, nor any sort of message-carrier. His aim was to point out the physical basis of music, and nothing more. But this fact that an electro-magnet would set a tuning-fork humming was new to Bell and very attractive. It appealed at once to him as a student of speech. If a tuning-fork could be made to sing by a magnet or an electrified wire, why would it not be possible to make a musical telegraph--a telegraph with a piano key-board, so that many messages could be sent at once over a single wire? Unknown to Bell, there were several dozen inven-tors then at work upon this problem, which proved in the end to be very elusive. But it gave him at least a starting-point, and he forthwith commenced his quest of the telephone. As he was then in England, his first step was naturally to visit Sir Charles Wheatstone, the best known English expert on telegraphy. Sir Charles had earned his title by many inventions. He was a simple-natured scientist, and treated Bell with the utmost kindness. He showed him an ingenious talking-machine that had been made by Baron de Kempelin. At this time Bell was twenty-two and unknown; Wheatstone was sixty-seven and famous. And the personality of the veteran scientist made so vivid a picture upon the mind of the impressionable young Bell that the grand passion of science became henceforth the master-motif of his life. From this summit of glorious ambition he was thrown, several months later, into the depths of grief and despondency. The White Plague had come to the home in Edinburgh and taken away his two brothers. More, it had put its mark upon the young inventor himself. Nothing but a change of climate, said his doctor, would put him out of danger. And so, to save his life, he and his father and mother set sail from Glasgow and came to the small Canadian town of Brantford, where for a year he fought down his tendency to consumption, and satisfied his nervous energy by teaching "Visible Speech" to a tribe of Mohawk Indians. By this time it had become evident, both to his parents and to his friends, that young Graham was destined to become some sort of a creative genius. He was tall and supple, with a pale complexion, large nose, full lips, jet-black eyes, and jet-black hair, brushed high and usually rumpled into a curly tangle. In temperament he was a true scientific Bohemian, with the ideals of a savant and the disposition of an artist. He was wholly a man of enthusiasms, more devoted to ideas than to people; and less likely to master his own thoughts than to be mastered by them. He had no shrewdness, in any commercial sense, and very little knowledge of the small practical details of ordinary living. He was always intense, always absorbed. When he applied his mind to a problem, it became at once an enthralling arena, in which there went whirling a chariot-race of ideas and inventive fancies. He had been fascinated from boyhood by his father's system of "Visible Speech." He knew it so well that he once astonished a professor of Oriental languages by repeating correctly a sentence of Sanscrit that had been written in "Visible Speech" characters. While he was living in London his most absorbing enthusiasm was the instruction of a class of deaf-mutes, who could be trained to talk, he believed, by means of the "Visible Speech" alphabet. He was so deeply impressed by the progress made by these pupils, and by the pathos of their dumbness, that when he arrived in Canada he was in doubt as to which of these two tasks was the more important--the teaching of deaf-mutes or the invention of a musical telegraph. At this point, and before Bell had begun to experiment with his telegraph, the scene of the story shifts from Canada to Massachusetts. It appears that his father, while lecturing in Boston, had mentioned Graham's exploits with a class of deaf-mutes; and soon afterward the Boston Board of Education wrote to Graham, offering him five hundred dollars if he would come to Boston and introduce his system of teaching in a school for deaf-mutes that had been opened recently. The young man joyfully agreed, and on the first of April, 1871, crossed the line and became for the remainder of his life an American. For the next two years his telegraphic work was laid aside, if not forgotten. His success as a teacher of deaf-mutes was sudden and overwhelming. It was the educational sensation of 1871. It won him a professorship in Boston University; and brought so many pupils around him that he ventured to open an ambitious "School of Vocal Physiology," which became at once a profitable enterprise. For a time there seemed to be little hope of his escaping from the burden of this success and becoming an inventor, when, by a most happy coincidence, two of his pupils brought to him exactly the sort of stimulation and practical help that he needed and had not up to this time received. One of these pupils was a little deaf-mute tot, five years of age, named Georgie Sanders. Bell had agreed to give him a series of private lessons for $350 a year; and as the child lived with his grandmother in the city of Salem, sixteen miles from Boston, it was agreed that Bell should make his home with the Sanders family. Here he not only found the keenest interest and sympathy in his air-castles of invention, but also was given permission to use the cellar of the house as his workshop. For the next three years this cellar was his favorite retreat. He littered it with tuning-forks, magnets, batteries, coils of wire, tin trumpets, and cigar-boxes. No one outside of the Sanders family was allowed to enter it, as Bell was nervously afraid of having his ideas stolen. He would even go to five or six stores to buy his supplies, for fear that his intentions should be discovered. Almost with the secrecy of a conspirator, he worked alone in this cellar, usually at night, and quite oblivious of the fact that sleep was a necessity to him and to the Sanders family. "Often in the middle of the night Bell would wake me up," said Thomas Sanders, the father of Georgie. "His black eyes would be blazing with excitement. Leaving me to go down to the cellar, he would rush wildly to the barn and begin to send me signals along his experimental wires. If I noticed any improvement in his machine, he would be delighted. He would leap and whirl around in one of his `war-dances' and then go contentedly to bed. But if the experiment was a failure, he would go back to his workbench and try some different plan." The second pupil who became a factor--a very considerable factor--in Bell's career was a fifteen-year-old girl named Mabel Hubbard, who had lost her hearing, and consequently her speech, through an attack of scarlet-fever when a baby. She was a gentle and lovable girl, and Bell, in his ardent and headlong way, lost his heart to her completely; and four years later, he had the happiness of making her his wife. Mabel Hubbard did much to encourage Bell. She followed each step of his progress with the keenest interest. She wrote his letters and copied his patents. She cheered him on when he felt himself beaten. And through her sympathy with Bell and his ambitions, she led her father--a widely known Boston lawyer named Gardiner G. Hubbard--to become Bell's chief spokesman and defender, a true apostle of the telephone. Hubbard first became aware of Bell's inventive efforts one evening when Bell was visiting at his home in Cambridge. Bell was illustrating some of the mysteries of acoustics by the aid of a piano. "Do you know," he said to Hubbard, "that if I sing the note G close to the strings of the piano, that the G-string will answer me?" "Well, what then?" asked Hubbard. "It is a fact of tremendous importance," replied Bell. "It is an evidence that we may some day have a musical telegraph, which will send as many messages simultaneously over one wire as there are notes on that piano." Later, Bell ventured to confide to Hubbard his wild dream of sending speech over an electric wire, but Hubbard laughed him to scorn. "Now you are talking nonsense," he said. "Such a thing never could be more than a scientific toy. You had better throw that idea out of your mind and go ahead with your musical telegraph, which if it is successful will make you a millionaire." But the longer Bell toiled at his musical telegraph, the more he dreamed of replacing the telegraph and its cumbrous sign-language by a new machine that would carry, not dots and dashes, but the human voice. "If I can make a deaf-mute talk," he said, "I can make iron talk." For months he wavered between the two ideas. He had no more than the most hazy conception of what this voice-carrying machine would be like. At first he conceived of having a harp at one end of the wire, and a speaking-trumpet at the other, so that the tones of the voice would be reproduced by the strings of the harp. Then, in the early Summer of 1874, while he was puzzling over this harp apparatus, the dim outline of a new path suddenly glinted in front of him. He had not been forgetful of "Visible Speech" all this while, but had been making experiments with two remarkable machines--the phonautograph and the manometric capsule, by means of which the vibrations of sound were made plainly visible. If these could be im-proved, he thought, then the deaf might be taught to speak by SIGHT--by learning an alphabet of vibrations. He mentioned these experiments to a Boston friend, Dr. Clarence J. Blake, and he, being a surgeon and an aurist, naturally said, "Why don't you use a REAL EAR?" Such an idea never had, and probably never could have, occurred to Bell; but he accepted it with eagerness. Dr. Blake cut an ear from a dead man's head, together with the ear-drum and the associated bones. Bell took this fragment of a skull and arranged it so that a straw touched the ear-drum at one end and a piece of moving smoked glass at the other. Thus, when Bell spoke loudly into the ear, the vibrations of the drum made tiny markings upon the glass. It was one of the most extraordinary incidents in the whole history of the telephone. To an uninitiated onlooker, nothing could have been more ghastly or absurd. How could any one have interpreted the gruesome joy of this young professor with the pale face and the black eyes, who stood earnestly singing, whispering, and shouting into a dead man's ear? What sort of a wizard must he be, or ghoul, or madman? And in Salem, too, the home of the witchcraft superstition! Certainly it would not have gone well with Bell had he lived two centuries earlier and been caught at such black magic. What had this dead man's ear to do with the invention of the telephone? Much. Bell noticed how small and thin was the ear-drum, and yet how effectively it could send thrills and vibrations through heavy bones. "If this tiny disc can vibrate a bone," he thought, "then an iron disc might vibrate an iron rod, or at least, an iron wire." In a flash the conception of a membrane telephone was pictured in his mind. He saw in imagination two iron discs, or ear-drums, far apart and connected by an electrified wire, catching the vibrations of sound at one end, and reproducing them at the other. At last he was on the right path, and had a theoretical knowledge of what a speaking telephone ought to be. What remained to be done was to construct such a machine and find out how the electric current could best be brought into harness. Then, as though Fortune suddenly felt that he was winning this stupendous success too easily, Bell was flung back by an avalanche of troubles. Sanders and Hubbard, who had been paying the cost of his experiments, abruptly announced that they would pay no more unless he confined his attention to the musical telegraph, and stopped wasting his time on ear-toys that never could be of any financial value. What these two men asked could scarcely be denied, as one of them was his best-paying patron and the other was the father of the girl whom he hoped to marry. "If you wish my daughter," said Hubbard, "you must abandon your foolish telephone." Bell's "School of Vocal Physiology," too, from which he had hoped so much, had come to an inglorious end. He had been too much absorbed in his experiments to sustain it. His professorship had been given up, and he had no pupils except Georgie Sanders and Mabel Hubbard. He was poor, much poorer than his associates knew. And his mind was torn and distracted by the contrary calls of science, poverty, business, and affection. Pouring out his sorrows in a letter to his mother, he said: "I am now beginning to realize the cares and anxieties of being an inventor. I have had to put off all pupils and classes, for flesh and blood could not stand much longer such a strain as I have had upon me." While stumbling through this Slough of Despond, he was called to Washington by his patent lawyer. Not having enough money to pay the cost of such a journey, he borrowed the price of a return ticket from Sanders and arranged to stay with a friend in Washington, to save a hotel bill that he could not afford. At that time Professor Joseph Henry, who knew more of the theory of electrical science than any other American, was the Grand Old Man of Washington; and poor Bell, in his doubt and desperation, resolved to run to him for advice. Then came a meeting which deserves to be historic. For an entire afternoon the two men worked together over the apparatus that Bell had brought from Boston, just as Henry had worked over the telegraph before Bell was born. Henry was now a veteran of seventy-eight, with only three years remaining to his credit in the bank of Time, while Bell was twenty-eight. There was a long half-century between them; but the youth had discovered a New Fact that the sage, in all his wisdom, had never known. "You are in possession of the germ of a great invention," said Henry, "and I would advise you to work at it until you have made it complete." "But," replied Bell, "I have not got the electrical knowledge that is necessary." "Get it," responded the aged scientist. "I cannot tell you how much these two words have encouraged me," said Bell afterwards, in describing this interview to his parents. "I live too much in an atmosphere of discouragement for scientific pursuits; and such a chimerical idea as telegraphing VOCAL SOUNDS would indeed seem to most minds scarcely feasible enough to spend time in working over." By this time Bell had moved his workshop from the cellar in Salem to 109 Court Street, Boston, where he had rented a room from Charles Williams, a manufacturer of electrical supplies. Thomas A. Watson was his assistant, and both Bell and Watson lived nearby, in two cheap little bedrooms. The rent of the workshop and bedrooms, and Watson's wages of nine dollars a week, were being paid by Sanders and Hubbard. Consequently, when Bell returned from Washington, he was compelled by his agreement to devote himself mainly to the musical telegraph, although his heart was now with the telephone. For exactly three months after his interview with Professor Henry, he continued to plod ahead, along both lines, until, on that memorable hot afternoon in June, 1875, the full TWANG of the clock-spring came over the wire, and the telephone was born. From this moment, Bell was a man of one purpose. He won over Sanders and Hubbard. He converted Watson into an enthusiast. He forgot his musical telegraph, his "Visible Speech," his classes, his poverty. He threw aside a profession in which he was already locally famous. And he grappled with this new mystery of electricity, as Henry had advised him to do, encouraging himself with the fact that Morse, who was only a painter, had mastered his electrical difficulties, and there was no reason why a professor of acoustics should not do as much. The telephone was now in existence, but it was the youngest and feeblest thing in the nation. It had not yet spoken a word. It had to be taught, developed, and made fit for the service of the irritable business world. All manner of discs had to be tried, some smaller and thinner than a dime and others of steel boiler-plate as heavy as the shield of Achilles. In all the books of electrical science, there was nothing to help Bell and Watson in this journey they were making through an unknown country. They were as chartless as Columbus was in 1492. Neither they nor any one else had acquired any experience in the rearing of a young telephone. No one knew what to do next. There was nothing to know. For forty weeks--long exasperating weeks--the telephone could do no more than gasp and make strange inarticulate noises. Its educators had not learned how to manage it. Then, on March 10, 1876, IT TALKED. It said distinctly-- "MR. WATSON, COME HERE, I WANT YOU." Watson, who was at the lower end of the wire, in the basement, dropped the receiver and rushed with wild joy up three flights of stairs to tell the glad tidings to Bell. "I can hear you!" he shouted breathlessly. "I can hear the WORDS." It was not easy, of course, for the weak young telephone to make itself heard in that noisy workshop. No one, not even Bell and Watson, was familiar with its odd little voice. Usually Watson, who had a remarkably keen sense of hearing, did the listening; and Bell, who was a professional elocutionist, did the talking. And day by day the tone of the baby instrument grew clearer--a new note in the orchestra of civilization. On his twenty-ninth birthday, Bell received his patent, No. 174,465--"the most valuable single patent ever issued" in any country. He had created something so entirely new that there was no name for it in any of the world's languages. In describing it to the officials of the Patent Office, he was obliged to call it "an improvement in telegraphy," when, in truth, it was nothing of the kind. It was as different from the telegraph as the eloquence of a great orator is from the sign-language of a deaf-mute. Other inventors had worked from the standpoint of the telegraph; and they never did, and never could, get any better results than signs and symbols. But Bell worked from the standpoint of the human voice. He cross-fertilized the two sciences of acoustics and electricity. His study of "Visible Speech" had trained his mind so that he could mentally SEE the shape of a word as he spoke it. He knew what a spoken word was, and how it acted upon the air, or the ether, that carried its vibrations from the lips to the ear. He was a third-generation specialist in the nature of speech, and he knew that for the transmission of spoken words there must be "a pulsatory action of the electric current which is the exact equivalent of the aerial impulses." Bell knew just enough about electricity, and not too much. He did not know the possible from the impossible. "Had I known more about electricity, and less about sound," he said, "I would never have invented the telephone." What he had done was so amazing, so foolhardy, that no trained electrician could have thought of it. It was "the very hardihood of invention," and yet it was not in any sense a chance discovery. It was the natural output of a mind that had been led to assemble just the right materials for such a product. As though the very stars in their courses were working for this young wizard with the talking wire, the Centennial Exposition in Philadelphia opened its doors exactly two months after the telephone had learned to talk. Here was a superb opportunity to let the wide world know what had been done, and fortunately Hubbard was one of the Centennial Commissioners. By his influence a small table was placed in the Department of Education, in a narrow space between a stairway and a wall, and on this table was deposited the first of the telephones. Bell had no intention of going to the Centennial himself. He was too poor. Sanders and Hubbard had never done more than pay his room-rent and the expense of his experiments. For his three or four years of inventing he had received nothing as yet--nothing but his patent. In order to live, he had been compelled to reorganize his classes in "Visible Speech," and to pick up the ravelled ends of his neglected profession. But one Friday afternoon, toward the end of June, his sweetheart, Mabel Hubbard, was taking the train for the Centennial; and he went to the depot to say good-bye. Here Miss Hubbard learned for the first time that Bell was not to go. She coaxed and pleaded, without effect. Then, as the train was starting, leaving Bell on the platform, the affectionate young girl could no longer control her feelings and was overcome by a passion of tears. At this the susceptible Bell, like a true Sir Galahad, dashed after the moving train and sprang aboard, without ticket or baggage, oblivious of his classes and his poverty and of all else except this one maiden's distress. "I never saw a man," said Watson, "so much in love as Bell was." As it happened, this impromptu trip to the Centennial proved to be one of the most timely acts of his life. On the following Sunday after-noon the judges were to make a special tour of inspection, and Mr. Hubbard, after much trouble, had obtained a promise that they would spend a few minutes examining Bell's telephone. By this time it had been on exhibition for more than six weeks, without attracting the serious attention of anybody. When Sunday afternoon arrived, Bell was at his little table, nervous, yet confident. But hour after hour went by, and the judges did not arrive. The day was intensely hot, and they had many wonders to examine. There was the first electric light, and the first grain-binder, and the musical telegraph of Elisha Gray, and the marvellous exhibit of printing telegraphs shown by the Western Union Company. By the time they came to Bell's table, through a litter of school-desks and blackboards, the hour was seven o'clock, and every man in the party was hot, tired, and hungry. Several announced their intention of returning to their hotels. One took up a telephone receiver, looked at it blankly, and put it down again. He did not even place it to his ear. Another judge made a slighting remark which raised a laugh at Bell's expense. Then a most marvellous thing happened--such an incident as would make a chapter in "The Arabian Nights Entertainments." Accompanied by his wife, the Empress Theresa, and by a bevy of courtiers, the Emperor of Brazil, Dom Pedro de Alcantara, walked into the room, advanced with both hands outstretched to the bewildered Bell, and exclaimed: "Professor Bell, I am delighted to see you again." The judges at once forgot the heat and the fatigue and the hunger. Who was this young inventor, with the pale complexion and black eyes, that he should be the friend of Emperors? They did not know, and for the moment even Bell himself had forgotten, that Dom Pedro had once visited Bell's class of deaf-mutes at Boston University. He was especially interested in such humanitarian work, and had recently helped to organize the first Brazilian school for deaf-mutes at Rio de Janeiro. And so, with the tall, blond-bearded Dom Pedro in the centre, the assembled judges, and scientists--there were fully fifty in all--entered with unusual zest into the proceedings of this first telephone exhibition. A wire had been strung from one end of the room to the other, and while Bell went to the transmitter, Dom Pedro took up the receiver and placed it to his ear. It was a moment of tense expectancy. No one knew clearly what was about to happen, when the Emperor, with a dramatic gesture, raised his head from the receiver and exclaimed with a look of utter amazement: "MY GOD--IT TALKS!" Next came to the receiver the oldest scientist in the group, the venerable Joseph Henry, whose encouragement to Bell had been so timely. He stopped to listen, and, as one of the bystanders afterwards said, no one could forget the look of awe that came into his face as he heard that iron disc talking with a human voice. "This," said he, "comes nearer to overthrowing the doctrine of the conservation of energy than anything I ever saw." Then came Sir William Thomson, latterly known as Lord Kelvin. It was fitting that he should be there, for he was the foremost electrical scientist at that time in the world, and had been the engineer of the first Atlantic Cable. He listened and learned what even he had not known before, that a solid metallic body could take up from the air all the countless varieties of vibrations produced by speech, and that these vibrations could be carried along a wire and reproduced exactly by a second metallic body. He nodded his head solemnly as he rose from the receiver. "It DOES speak," he said emphatically. "It is the most wonderful thing I have seen in America." So, one after another, this notable company of men listened to the voice of the first telephone, and the more they knew of science, the less they were inclined to believe their ears. The wiser they were, the more they wondered. To Henry and Thomson, the masters of electrical magic, this instrument was as surprising as it was to the man in the street. And both were noble enough to admit frankly their astonishment in the reports which they made as judges, when they gave Bell a Certificate of Award. "Mr. Bell has achieved a result of transcendent scientific interest," wrote Sir William Thomson. "I heard it speak distinctly several sentences.... I was astonished and delighted.... It is the greatest marvel hitherto achieved by the electric telegraph." Until nearly ten o'clock that night the judges talked and listened by turns at the telephone. Then, next morning, they brought the apparatus to the judges' pavilion, where for the remainder of the summer it was mobbed by judges and scientists. Sir William Thomson and his wife ran back and forth between the two ends of the wire like a pair of delighted children. And thus it happened that the crude little instrument that had been tossed into an out-of-the-way corner became the star of the Centennial. It had been given no more than eighteen words in the official catalogue, and here it was acclaimed as the wonder of wonders. It had been conceived in a cellar and born in a machine-shop; and now, of all the gifts that our young American Republic had received on its one-hundredth birthday, the telephone was honored as the rarest and most welcome of them all. CHAPTER II. THE BUILDING OF THE BUSINESS After the telephone had been born in Boston, baptized in the Patent Office, and given a royal reception at the Philadelphia Centennial, it might be supposed that its life thenceforth would be one of peace and pleasantness. But as this is history, and not fancy, there must be set down the very surprising fact that the young newcomer received no welcome and no notice from the great business world. "It is a scientific toy," said the men of trade and commerce. "It is an interesting instrument, of course, for professors of electricity and acoustics; but it can never be a practical necessity. As well might you propose to put a telescope into a steel-mill or to hitch a balloon to a shoe-factory." Poor Bell, instead of being applauded, was pelted with a hailstorm of ridicule. He was an "impostor," a "ventriloquist," a "crank who says he can talk through a wire." The London Times alluded pompously to the telephone as the latest American humbug, and gave many profound reasons why speech could not be sent over a wire, because of the intermittent nature of the electric current. Almost all electricians--the men who were supposed to know--pronounced the telephone an impossible thing; and those who did not openly declare it to be a hoax, believed that Bell had stumbled upon some freakish use of electricity, which could never be of any practical value. Even though he came late in the succession of inventors, Bell had to run the gantlet of scoffing and adversity. By the reception that the public gave to his telephone, he learned to sympathize with Howe, whose first sewing-machine was smashed by a Boston mob; with McCormick, whose first reaper was called "a cross between an Astley chariot, a wheelbarrow, and a flying-machine"; with Morse, whom ten Congresses regarded as a nuisance; with Cyrus Field, whose Atlantic Cable was denounced as "a mad freak of stubborn ignorance"; and with Westinghouse, who was called a fool for proposing "to stop a railroad train with wind." The very idea of talking at a piece of sheet-iron was so new and extraordinary that the normal mind repulsed it. Alike to the laborer and the scientist, it was incomprehensible. It was too freakish, too bizarre, to be used outside of the laboratory and the museum. No one, literally, could understand how it worked; and the only man who offered a clear solution of the mystery was a Boston mechanic, who maintained that there was "a hole through the middle of the wire." People who talked for the first time into a telephone box had a sort of stage fright. They felt foolish. To do so seemed an absurd performance, especially when they had to shout at the top of their voices. Plainly, whatever of convenience there might be in this new contrivance was far outweighed by the loss of personal dignity; and very few men had sufficient imagination to picture the telephone as a part of the machinery of their daily work. The banker said it might do well enough for grocers, but that it would never be of any value to banking; and the grocer said it might do well enough for bankers, but that it would never be of any value to grocers. As Bell had worked out his invention in Salem, one editor displayed the headline, "Salem Witchcraft." The New York Herald said: "The effect is weird and almost supernatural." The Providence Press said: "It is hard to resist the notion that the powers of darkness are somehow in league with it." And The Boston Times said, in an editorial of bantering ridicule: "A fellow can now court his girl in China as well as in East Boston; but the most serious aspect of this invention is the awful and irresponsible power it will give to the average mother-in-law, who will be able to send her voice around the habitable globe." There were hundreds of shrewd capitalists in American cities in 1876, looking with sharp eyes in all directions for business chances; but not one of them came to Bell with an offer to buy his patent. Not one came running for a State contract. And neither did any legislature, or city council, come forward to the task of giving the people a cheap and efficient telephone service. As for Bell himself, he was not a man of affairs. In all practical business matters, he was as incompetent as a Byron or a Shelley. He had done his part, and it now remained for men of different abilities to take up his telephone and adapt it to the uses and conditions of the business world. The first man to undertake this work was Gardiner G. Hubbard, who became soon afterwards the father-in-law of Bell. He, too, was a man of enthusiasm rather than of efficiency. He was not a man of wealth or business experience, but he was admirably suited to introduce the telephone to a hostile public. His father had been a judge of the Massachusetts Supreme Court; and he himself was a lawyer whose practice had been mainly in matters of legislation. He was, in 1876, a man of venerable appearance, with white hair, worn long, and a patriarchal beard. He was a familiar figure in Washington, and well known among the public men of his day. A versatile and entertaining companion, by turns prosperous and impecunious, and an optimist always, Gardiner Hubbard became a really indispensable factor as the first advance agent of the telephone business. No other citizen had done more for the city of Cambridge than Hubbard. It was he who secured gas for Cambridge in 1853, and pure water, and a street-railway to Boston. He had gone through the South in 1860 in the patriotic hope that he might avert the impending Civil War. He had induced the legislature to establish the first public school for deaf-mutes, the school that drew Bell to Boston in 1871. And he had been for years a most restless agitator for improvements in telegraphy and the post office. So, as a promoter of schemes for the public good, Hubbard was by no means a novice. His first step toward capturing the attention of an indifferent nation was to beat the big drum of publicity. He saw that this new idea of telephoning must be made familiar to the public mind. He talked telephone by day and by night. Whenever he travelled, he carried a pair of the magical instruments in his valise, and gave demonstrations on trains and in hotels. He buttonholed every influential man who crossed his path. He was a veritable "Ancient Mariner" of the telephone. No possible listener was allowed to escape. Further to promote this campaign of publicity, Hubbard encouraged Bell and Watson to perform a series of sensational feats with the telephone. A telegraph wire between New York and Boston was borrowed for half an hour, and in the presence of Sir William Thomson, Bell sent a tune over the two-hundred-and-fifty-mile line. "Can you hear?" he asked the operator at the New York end. "Elegantly," responded the operator. "What tune?" asked Bell. "Yankee Doodle," came the answer. Shortly afterwards, while Bell was visiting at his father's house in Canada, he bought up all the stove-pipe wire in the town, and tacked it to a rail fence between the house and a telegraph office. Then he went to a village eight miles distant and sent scraps of songs and Shakespearean quotations over the wire. There was still a large percentage of people who denied that spoken words could be transmitted by a wire. When Watson talked to Bell at public demonstrations, there were newspaper editors who referred sceptically to "the supposititious Watson." So, to silence these doubters, Bell and Watson planned a most severe test of the telephone. They borrowed the telegraph line between Boston and the Cambridge Observatory, and attached a telephone to each end. Then they maintained, for three hours or longer, the FIRST SUSTAINED conversation by telephone, each one taking careful notes of what he said and of what he heard. These notes were published in parallel columns in The Boston Advertiser, October 19, 1876, and proved beyond question that the telephone was now a practical success. After this, one event crowded quickly on the heels of another. A series of ten lectures was arranged for Bell, at a hundred dollars a lecture, which was the first money payment he had received for his invention. His opening night was in Salem, before an audience of five hundred people, and with Mrs. Sand-ers, the motherly old lady who had sheltered Bell in the days of his experiment, sitting proudly in one of the front seats. A pole was set up at the front of the hall, supporting the end of a telegraph wire that ran from Salem to Boston. And Watson, who became the first public talker by telephone, sent messages from Boston to various members of the audience. An account of this lecture was sent by telephone to The Boston Globe, which announced the next morning-- "This special despatch of the Globe has been transmitted by telephone in the presence of twenty people, who have thus been witnesses to a feat never before attempted--the sending of news over the space of sixteen miles by the human voice." This Globe despatch awoke the newspaper editors with an unexpected jolt. For the first time they began to notice that there was a new word in the language, and a new idea in the scientific world. No newspaper had made any mention whatever of the telephone for seventy-five days after Bell received his patent. Not one of the swarm of reporters who thronged the Philadelphia Centennial had regarded the telephone as a matter of any public interest. But when a column of news was sent by telephone to The Boston Globe, the whole newspaper world was agog with excitement. A thousand pens wrote the name of Bell. Requests to repeat his lecture came to Bell from Cyrus W. Field, the veteran of the Atlantic Cable, from the poet Longfellow, and from many others. As he was by profession an elocutionist, Bell was able to make the most of these opportunities. His lectures became popular entertainments. They were given in the largest halls. At one lecture two Japanese gentlemen were induced to talk to one another in their own language, via the telephone. At a second lecture a band played "The Star-Spangled Banner," in Boston, and was heard by an audience of two thousand people in Providence. At a third, Signor Ferranti, who was in Providence, sang a selection from "The Marriage of Figaro" to an audience in Boston. At a fourth, an exhortation from Moody and a song from Sankey came over the vibrating wire. And at a fifth, in New Haven, Bell stood sixteen Yale professors in line, hand in hand, and talked through their bodies--a feat which was then, and is to-day, almost too wonderful to believe. Very slowly these lectures, and the tireless activity of Hubbard, pushed back the ridicule and the incredulity; and in the merry month of May, 1877, a man named Emery drifted into Hubbard's office from the near-by city of Charlestown, and leased two telephones for twenty actual dollars--the first money ever paid for a telephone. This was the first feeble sign that such a novelty as the telephone business could be established; and no money ever looked handsomer than this twenty dollars did to Bell, Sanders, Hubbard, and Watson. It was the tiny first-fruit of fortune. Greatly encouraged, they prepared a little circular which was the first advertisement of the telephone business. It is an oddly simple little document to-day, but to the 1877 brain it was startling. It modestly claimed that a telephone was superior to a telegraph for three reasons: "(1) No skilled operator is required, but direct communication may be had by speech without the intervention of a third person. "(2) The communication is much more rapid, the average number of words transmitted in a minute by the Morse sounder being from fifteen to twenty, by telephone from one to two hundred. "(3) No expense is required, either for its operation or repair. It needs no battery and has no complicated machinery. It is unsurpassed for economy and simplicity." The only telephone line in the world at this time was between the Williams' workshop in Boston and the home of Mr. Williams in Somerville. But in May, 1877, a young man named E. T. Holmes, who was running a burglar-alarm business in Boston, proposed that a few telephones be linked to his wires. He was a friend and customer of Williams, and suggested this plan half in jest and half in earnest. Hubbard was quick to seize this opportunity, and at once lent Holmes a dozen telephones. Without asking permission, Holmes went into six banks and nailed up a telephone in each. Five bankers made no protest, but the sixth indignantly ordered "that playtoy" to be taken out. The other five telephones could be connected by a switch in Holmes's office, and thus was born the first tiny and crude Telephone Exchange. Here it ran for several weeks as a telephone system by day and a burglar-alarm by night. No money was paid by the bankers. The service was given to them as an exhibition and an advertisement. The little shelf with its five telephones was no more like the marvellous exchanges of to-day than a canoe is like a Cunarder, but it was unquestionably the first place where several telephone wires came together and could be united. Soon afterwards, Holmes took his telephones out of the banks, and started a real telephone business among the express companies of Boston. But by this time several exchanges had been opened for ordinary business, in New Haven, Bridgeport, New York, and Philadelphia. Also, a man from Michigan had arrived, with the hardihood to ask for a State agency--George W. Balch, of Detroit. He was so welcome that Hubbard joyfully gave him everything he asked--a perpetual right to the whole State of Michigan. Balch was not required to pay a cent in advance, except his railway fare, and before he was many years older he had sold his lease for a handsome fortune of a quarter of a million dollars, honestly earned by his initiative and enterprise. By August, when Bell's patent was sixteen months old, there were 778 telephones in use. This looked like success to the optimistic Hubbard. He decided that the time had come to organize the business, so he created a simple agreement which he called the "Bell Telephone Association." This agreement gave Bell, Hubbard and Sanders a three-tenths interest apiece in the patents, and Watson one-tenth. THERE WAS NO CAPITAL. There was none to be had. The four men had at this time an absolute monopoly of the telephone business; and everybody else was quite willing that they should have it. The only man who had money and dared to stake it on the future of the telephone was Thomas Sanders, and he did this not mainly for business reasons. Both he and Hubbard were attached to Bell primarily by sentiment, as Bell had removed the blight of dumbness from Sanders's little son, and was soon to marry Hubbard's daughter. Also, Sanders had no expectation, at first, that so much money would be needed. He was not rich. His entire business, which was that of cutting out soles for shoe manufacturers, was not at any time worth more than thirty-five thousand dollars. Yet, from 1874 to 1878, he had advanced nine-tenths of the money that was spent on the telephone. He had paid Bell's room-rent, and Watson's wages, and Williams's expenses, and the cost of the exhibit at the Centennial. The first five thousand telephones, and more, were made with his money. And so many long, expensive months dragged by before any relief came to Sanders, that he was compelled, much against his will and his business judgment, to stretch his credit within an inch of the breaking-point to help Bell and the telephone. Desperately he signed note after note until he faced a total of one hundred and ten thousand dollars. If the new "scientific toy" succeeded, which he often doubted, he would be the richest citizen in Haverhill; and if it failed, which he sorely feared, he would be a bankrupt. A disheartening series of rebuffs slowly forced the truth in upon Sanders's mind that the business world refused to accept the telephone as an article of commerce. It was a toy, a plaything, a scientific wonder, but not a necessity to be bought and used for ordinary purposes by ordinary people. Capitalists treated it exactly as they treated the Atlantic Cable project when Cyrus Field visited Boston in 1862. They admired and marvelled; but not a man subscribed a dollar. Also, Sanders very soon learned that it was a most unpropitious time for the setting afloat of a new enterprise. It was a period of turmoil and suspicion. What with the Jay Cooke failure, the Hayes-Tilden deadlock, and the bursting of a hundred railroad bubbles, there was very little in the news of the day to encourage investors. It was impossible for Sanders, or Bell, or Hubbard, to prepare any definite plan. No matter what the plan might have been, they had no money to put it through. They believed that they had something new and marvellous, which some one, somewhere, would be willing to buy. Until this good genie should arrive, they could do no more than flounder ahead, and take whatever business was the nearest and the cheapest. So while Bell, in eloquent rhapsodies, painted word-pictures of a universal telephone service to applauding audiences, Sanders and Hubbard were leasing telephones two by two, to business men who previously had been using the private lines of the Western Union Telegraph Company. This great corporation was at the time their natural and inevitable enemy. It had swallowed most of its competitors, and was reaching out to monopolize all methods of communication by wire. The rosiest hope that shone in front of Sanders and Hubbard was that the Western Union might conclude to buy the Bell patents, just as it had already bought many others. In one moment of discouragement they had offered the telephone to President Orton, of the Western Union, for $100,000; and Orton had refused it. "What use," he asked pleasantly, "could this company make of an electrical toy?" But besides the operation of its own wires, the Western Union was supplying customers with various kinds of printing-telegraphs and dial telegraphs, some of which could transmit sixty words a minute. These accurate instruments, it believed, could never be displaced by such a scientific oddity as the telephone. And it continued to believe this until one of its subsidiary companies--the Gold and Stock--reported that several of its machines had been superseded by telephones. At once the Western Union awoke from its indifference. Even this tiny nibbling at its business must be stopped. It took action quickly and organized the "American Speaking-Telephone Company," with $300,000 capital, and with three electrical inventors, Edison, Gray, and Dolbear, on its staff. With all the bulk of its great wealth and prestige, it swept down upon Bell and his little bodyguard. It trampled upon Bell's patent with as little concern as an elephant can have when he tramples upon an ant's nest. To the complete bewilderment of Bell, it coolly announced that it had "the only original telephone," and that it was ready to supply "superior telephones with all the latest improvements made by the original inventors--Dolbear, Gray, and Edison." The result was strange and unexpected. The Bell group, instead of being driven from the field, were at once lifted to a higher level in the business world. The effect was as if the Standard Oil Company were to commence the manufacture of aeroplanes. In a flash, the telephone ceased to be a "scientific toy," and became an article of commerce. It began for the first time to be taken seriously. And the Western Union, in the endeavor to protect its private lines, became involuntarily a bell-wether to lead capitalists in the direction of the telephone. Sanders's relatives, who were many and rich, came to his rescue. Most of them were well-known business men--the Bradleys, the Saltonstalls, Fay, Silsbee, and Carlton. These men, together with Colonel William H. Forbes, who came in as a friend of the Bradleys, were the first capitalists who, for purely business reasons, invested money in the Bell patents. Two months after the Western Union had given its weighty endorsement to the telephone, these men organized a company to do business in New England only, and put fifty thousand dollars in its treasury. In a short time the delighted Hubbard found himself leasing telephones at the rate of a thousand a month. He was no longer a promoter, but a general manager. Men were standing in line to ask for agencies. Crude little telephone exchanges were being started in a dozen or more cities. There was a spirit of confidence and enterprise; and the next step, clearly, was to create a business organization. None of the partners were competent to undertake such a work. Hubbard had little aptitude as an organizer; Bell had none; and Sanders was held fast by his leather interests. Here, at last, after four years of the most heroic effort, were the raw materials out of which a telephone business could be constructed. But who was to be the builder, and where was he to be found? One morning the indefatigable Hubbard solved the problem. "Watson," he said, "there's a young man in Washington who can handle this situation, and I want you to run down and see what you think of him." Watson went, reported favorably, and in a day or so the young man received a letter from Hubbard, offering him the position of General Manager, at a salary of thirty-five hundred dollars a year. "We rely," Hubbard said, "upon your executive ability, your fidelity, and unremitting zeal." The young man replied, in one of those dignified letters more usual in the nineteenth than in the twentieth century. "My faith in the success of the enterprise is such that I am willing to trust to it," he wrote, "and I have confidence that we shall establish the harmony and cooperation that is essential to the success of an enterprise of this kind." One week later the young man, Theodore N. Vail, took his seat as General Manager in a tiny office in Reade Street, New York, and the building of the business began. This arrival of Vail at the critical moment emphasized the fact that Bell was one of the most fortunate of inventors. He was not robbed of his invention, as might easily have happened. One by one there arrived to help him a number of able men, with all the various abilities that the changing situation required. There was such a focussing of factors that the whole matter appeared to have been previously rehearsed. No sooner had Bell appeared on the stage than his supporting players, each in his turn, received his cue and took part in the action of the drama. There was not one of these men who could have done the work of any other. Each was distinctive and indispensable. Bell invented the telephone; Watson constructed it; Sanders financed it; Hubbard introduced it; and Vail put it on a business basis. The new General Manager had, of course, no experience in the telephone business. Neither had any one else. But he, like Bell, came to his task with a most surprising fitness. He was a member of the historic Vail family of Morristown, New Jersey, which had operated the Speedwell Iron Works for four or five generations. His grand-uncle Stephen had built the engines for the Savannah, the first American steamship to cross the Atlantic Ocean; and his cousin Alfred was the friend and co-worker of Morse, the inventor of the telegraph. Morse had lived for several years at the Vail homestead in Morristown; and it was here that he erected his first telegraph line, a three-mile circle around the Iron Works, in 1838. He and Alfred Vail experimented side by side in the making of the telegraph, and Vail eventually received a fortune for his share of the Morse patent. Thus it happened that young Theodore Vail learned the dramatic story of Morse at his mother's knee. As a boy, he played around the first telegraph line, and learned to put messages on the wire. His favorite toy was a little telegraph that he constructed for himself. At twenty-two he went West, in the vague hope of possessing a bonanza farm; then he swung back into telegraphy, and in a few years found himself in the Government Mail Service at Washington. By 1876, he was at the head of this Department, which he completely reorganized. He introduced the bag system in postal cars, and made war on waste and clumsiness. By virtue of this position he was the one man in the United States who had a comprehensive view of all railways and telegraphs. He was much more apt, consequently, than other men to develop the idea of a national telephone system. While in the midst of this bureaucratic house-cleaning he met Hubbard, who had just been appointed by President Hayes as the head of a commission on mail transportation. He and Hubbard were constantly thrown together, on trains and in hotels; and as Hubbard invariably had a pair of telephones in his valise, the two men soon became co-enthusiasts. Vail found himself painting brain-pictures of the future of the telephone, and by the time that he was asked to become its General Manager, he had become so confident that, as he said afterwards, he "was willing to leave a Government job with a small salary for a telephone job with no salary." So, just as Amos Kendall had left the post office service thirty years before to establish the telegraph business, Theodore N. Vail left the post office service to establish the telephone business. He had been in authority over thirty-five hundred postal employees, and was the developer of a system that covered every inhabited portion of the country. Consequently, he had a quality of experience that was immensely valuable in straightening out the tangled affairs of the telephone. Line by line, he mapped out a method, a policy, a system. He introduced a larger view of the telephone business, and swept off the table all schemes for selling out. He persuaded half a dozen of his post office friends to buy stock, so that in less than two months the first "Bell Telephone Company" was organized, with $450,000 capital and a service of twelve thousand telephones. Vail's first step, naturally, was to stiffen up the backbone of this little company, and to prevent the Western Union from frightening it into a surrender. He immediately sent a copy of Bell's patent to every agent, with orders to hold the fort against all opposition. "We have the only original telephone patents," he wrote; "we have organized and introduced the business, and we do not propose to have it taken from us by any corporation." To one agent, who was showing the white feather, he wrote: "You have too great an idea of the Western Union. If it was all massed in your one city you might well fear it; but it is represented there by one man only, and he has probably as much as he can attend to outside of the telephone. For you to acknowledge that you cannot compete with his influence when you make it your special business, is hardly the thing. There may be a dozen concerns that will all go to the Western Union, but they will not take with them all their friends. I would advise that you go ahead and keep your present advantage. We must organize companies with sufficient vitality to carry on a fight, as it is simply useless to get a company started that will succumb to the first bit of opposition it may encounter." Next, having encouraged his thoroughly alarmed agents, Vail proceeded to build up a definite business policy. He stiffened up the contracts and made them good for five years only. He confined each agent to one place, and reserved all rights to connect one city with another. He established a department to collect and protect any new inventions that concerned the telephone. He agreed to take part of the royalties in stock, when any local company preferred to pay its debts in this way. And he took steps toward standardizing all telephonic apparatus by controlling the factories that made it. These various measures were part of Vail's plan to create a national telephone system. His central idea, from the first, was not the mere leasing of telephones, but rather the creation of a Federal company that would be a permanent partner in the entire telephone business. Even in that day of small things, and amidst the confusion and rough-and-tumble of pioneering, he worked out the broad policy that prevails to-day; and this goes far to explain the fact that there are in the United States twice as many telephones as there are in all other countries combined. Vail arrived very much as Blucher did at the battle of Waterloo--a trifle late, but in time to prevent the telephone forces from being routed by the Old Guard of the Western Union. He was scarcely seated in his managerial chair, when the Western Union threw the entire Bell army into confusion by launching the Edison transmitter. Edison, who was at that time fairly started in his career of wizardry, had made an instrument of marvellous alertness. It was beyond all argument superior to the telephones then in use and the lessees of Bell telephones clamored with one voice for "a transmitter as good as Edison's." This, of course, could not be had in a moment, and the five months that followed were the darkest days in the childhood of the telephone. How to compete with the Western Union, which had this superior transmitter, a host of agents, a network of wires, forty millions of capital, and a first claim upon all newspapers, hotels, railroads, and rights of way--that was the immediate problem that confronted the new General Manager. Every inch of progress had to be fought for. Several of his captains deserted, and he was compelled to take control of their unprofitable exchanges. There was scarcely a mail that did not bring him some bulletin of discouragement or defeat. In the effort to conciliate a hostile public, the telephone rates had everywhere been made too low. Hubbard had set a price of twenty dollars a year, for the use of two telephones on a private line; and when exchanges were started, the rate was seldom more than three dollars a month. There were deadheads in abundance, mostly officials and politicians. In St. Louis, one of the few cities that charged a sufficient price, nine-tenths of the merchants refused to become subscribers. In Boston, the first pay-station ran three months before it earned a dollar. Even as late as 1880, when the first National Telephone Convention was held at Niagara Falls, one of the delegates expressed the general situation very correctly when he said: "We were all in a state of enthusiastic uncertainty. We were full of hope, yet when we analyzed those hopes they were very airy indeed. There was probably not one company that could say it was making a cent, nor even that it EXPECTED to make a cent." Especially in the largest cities, where the Western Union had most power, the lives of the telephone pioneers were packed with hardships and adventures. In Philadelphia, for instance, a resolute young man named Thomas E. Cornish was attacked as though he had suddenly become a public enemy, when he set out to establish the first telephone service. No official would grant him a permit to string wires. His workmen were arrested. The printing-telegraph men warned him that he must either quit or be driven out. When he asked capitalists for money, they replied that he might as well expect to lease jew's-harps as telephones. Finally, he was compelled to resort to strategy where argument had failed. He had received an order from Colonel Thomas Scott, who wanted a wire between his house and his office. Colonel Scott was the President of the Pennsylvania Railroad, and therefore a man of the highest prestige in the city. So as soon as Cornish had put this line in place, he kept his men at work stringing other lines. When the police interfered, he showed them Colonel Scott's signature and was let alone. In this way he put fifteen wires up before the trick was discovered; and soon afterwards, with eight subscribers, he founded the first Philadelphia exchange. As may be imagined, such battling as this did not put much money into the treasury of the parent company; and the letters written by Sanders at this time prove that it was in a hard plight. The following was one of the queries put to Hubbard by the overburdened Sanders: "How on earth do you expect me to meet a draft of two hundred and seventy-five dollars without a dollar in the treasury, and with a debt of thirty thousand dollars staring us in the face?" "Vail's salary is small enough," he continued in a second letter, "but as to where it is coming from I am not so clear. Bradley is awfully blue and discouraged. Williams is tormenting me for money and my personal credit will not stand everything. I have advanced the Company two thousand dollars to-day, and Williams must have three thousand dollars more this month. His pay-day has come and his capital will not carry him another inch. If Bradley throws up his hand, I will unfold to you my last desperate plan." And if the company had little money, it had less credit. Once when Vail had ordered a small bill of goods from a merchant named Tillotson, of 15 Dey Street, New York, the merchant replied that the goods were ready, and so was the bill, which was seven dollars. By a strange coincidence, the magnificent building of the New York Telephone Company stands to-day on the site of Tillotson's store. Month after month, the little Bell Company lived from hand to mouth. No salaries were paid in full. Often, for weeks, they were not paid at all. In Watson's note-book there are such entries during this period as "Lent Bell fifty cents," "Lent Hubbard twenty cents," "Bought one bottle beer--too bad can't have beer every day." More than once Hubbard would have gone hungry had not Devonshire, the only clerk, shared with him the contents of a dinner-pail. Each one of the little group was beset by taunts and temptations. Watson was offered ten thousand dollars for his one-tenth interest, and hesitated three days before refusing it. Railroad companies offered Vail a salary that was higher and sure, if he would superintend their mail business. And as for Sanders, his folly was the talk of Haverhill. One Haverhill capitalist, E. J. M. Hale, stopped him on the street and asked, "Have n't you got a good leather business, Mr. Sanders?" "Yes," replied Sanders. "Well," said Hale, "you had better attend to it and quit playing on wind instruments." Sanders's banker, too, became uneasy on one occasion and requested him to call at the bank. "Mr. Sanders," he said, "I will be obliged if you will take that telephone stock out of the bank, and give me in its place your note for thirty thousand dollars. I am expecting the examiner here in a few days, and I don't want to get caught with that stuff in the bank." Then, in the very midnight of this depression, poor Bell returned from England, whither he and his bride had gone on their honeymoon, and announced that he had no money; that he had failed to establish a telephone business in England; and that he must have a thousand dollars at once to pay his urgent debts. He was thoroughly discouraged and sick. As he lay in the Massachusetts General Hospital, he wrote a cry for help to the embattled little company that was making its desperate fight to protect his patents. "Thousands of telephones are now in operation in all parts of the country," he said, "yet I have not yet received one cent from my invention. On the contrary, I am largely out of pocket by my researches, as the mere value of the profession that I have sacrificed during my three years' work, amounts to twelve thousand dollars." Fortunately, there came, in almost the same mail with Bell's letter, another letter from a young Bostonian named Francis Blake, with the good news that he had invented a transmitter as satisfactory as Edison's, and that he would prefer to sell it for stock instead of cash. If ever a man came as an angel of light, that man was Francis Blake. The possession of his transmitter instantly put the Bell Company on an even footing with the Western Union, in the matter of apparatus. It encouraged the few capitalists who had invested money, and it stirred others to come forward. The general business situation had by this time become more settled, and in four months the company had twenty-two thousand telephones in use, and had reorganized into the National Bell Telephone Company, with $850, 000 capital and with Colonel Forbes as its first President. Forbes now picked up the load that had been carried so long by Sanders. As the son of an East India merchant and the son-in-law of Ralph Waldo Emerson, he was a Bostonian of the Brahmin caste. He was a big, four-square man who was both popular and efficient; and his leadership at this crisis was of immense value. This reorganization put the telephone business into the hands of competent business men at every point. It brought the heroic and experimental period to an end. From this time onwards the telephone had strong friends in the financial world. It was being attacked by the Western Union and by rival inventors who were jealous of Bell's achievement. It was being half-starved by cheap rates and crippled by clumsy apparatus. It was being abused and grumbled at by an impatient public. But the art of making and marketing it had at last been built up into a commercial enterprise. It was now a business, fighting for its life. CHAPTER III. THE HOLDING OF THE BUSINESS For seventeen months no one disputed Bell's claim to be the original inventor of the telephone. All the honor, such as it was, had been given to him freely, and no one came forward to say that it was not rightfully his. No one, so far as we know, had any strong desire to do so. No one conceived that the telephone would ever be any more than a whimsical oddity of science. It was so new, so unexpected, that from Lord Kelvin down to the messenger boys in the telegraph offices, it was an incomprehensible surprise. But after Bell had explained his invention in public lectures before more than twenty thousand people, after it had been on exhibition for months at the Philadelphia Centennial, after several hundred articles on it had appeared in newspapers and scientific magazines, and after actual sales of telephones had been made in various parts of the country, there began to appear such a succession of claimants and infringers that the forgetful public came to believe that the telephone, like most inventions, was the product of many minds. Just as Morse, who was the sole inventor of the American telegraph in 1837, was confronted by sixty-two rivals in 1838, so Bell, who was the sole inventor in 1876, found himself two years later almost mobbed by the "Tichborne claimants" of the telephone. The inventors who had been his competitors in the attempt to produce a musical telegraph, persuaded themselves that they had unconsciously done as much as he. Any possessor of a telegraphic patent, who had used the common phrase "talking wire," had a chance to build up a plausible story of prior invention. And others came forward with claims so vague and elusive that Bell would scarcely have been more surprised if the heirs of Goethe had demanded a share of the telephone royalties on the ground that Faust had spoken of "making a bridge through the moving air." This babel of inventors and pretenders amazed Bell and disconcerted his backers. But it was no more than might have been expected. Here was a patent--"the most valuable single patent ever issued"--and yet the invention itself was so simple that it could be duplicated easily by any smart boy or any ordinary mechanic. The making of a telephone was like the trick of Columbus standing an egg on end. Nothing was easier to those who knew how. And so it happened that, as the crude little model of Bell's original telephone lay in the Patent Office open and unprotected except by a few phrases that clever lawyers might evade, there sprang up inevitably around it the most costly and persistent Patent War that any country has ever known, continuing for eleven years and comprising SIX HUNDRED LAWSUITS. The first attack upon the young telephone business was made by the Western Union Telegraph Company. It came charging full tilt upon Bell, driving three inventors abreast--Edison, Gray, and Dolbear. It expected an easy victory; in fact, the disparity between the two opponents was so evident, that there seemed little chance of a contest of any kind. "The Western Union will swallow up the telephone people," said public opinion, "just as it has already swallowed up all improvements in telegraphy." At that time, it should be remembered, the Western Union was the only corporation that was national in its extent. It was the most powerful electrical company in the world, and, as Bell wrote to his parents, "probably the largest corporation that ever existed." It had behind it not only forty millions of capital, but the prestige of the Vanderbilts, and the favor of financiers everywhere. Also, it met the telephone pioneers at every point because it, too, was a WIRE company. It owned rights-of-way along roads and on house-tops. It had a monopoly of hotels and railroad offices. No matter in what direction the Bell Company turned, the live wire of the Western Union lay across its path. From the first, the Western Union relied more upon its strength than upon the merits of its case. Its chief electrical expert, Frank L. Pope, had made a six months' examination of the Bell patents. He had bought every book in the United States and Europe that was likely to have any reference to the transmission of speech, and employed a professor who knew eight languages to translate them. He and his men ransacked libraries and patent offices; they rummaged and sleuthed and interviewed; and found nothing of any value. In his final report to the Western Union, Mr. Pope announced that there was no way to make a telephone except Bell's way, and advised the purchase of the Bell patents. "I am entirely unable to discover any apparatus or method anticipating the invention of Bell as a whole," he said; "and I conclude that his patent is valid." But the officials of the great corporation refused to take this report seriously. They threw it aside and employed Edison, Gray, and Dolbear to devise a telephone that could be put into competition with Bell's. As we have seen in the previous chapter, there now came a period of violent competition which is remembered as the Dark Ages of the telephone business. The Western Union bought out several of the Bell exchanges and opened up a lively war on the others. As befitting its size, it claimed everything. It introduced Gray as the original inventor of the telephone, and ordered its lawyers to take action at once against the Bell Company for infringement of the Gray patent. This high-handed action, it hoped, would most quickly bring the little Bell group into a humble and submissive frame of mind. Every morning the Western Union looked to see the white flag flying over the Bell headquarters. But no white flag appeared. On the contrary, the news came that the Bell Company had secured two eminent lawyers and were ready to give battle. The case began in the Autumn of 1878 and lasted for a year. Then it came to a sudden and most unexpected ending. The lawyer-in-chief of the Western Union was George Gifford, who was perhaps the ablest patent attorney of his day. He was versed in patent lore from Alpha to Omega; and as the trial proceeded, he became convinced that the Bell patent was valid. He notified the Western Union confidentially, of course, that its case could not be proven, and that "Bell was the original inventor of the telephone." The best policy, he suggested, was to withdraw their claims and make a settlement. This wise advice was accepted, and the next day the white flag was hauled up, not by the little group of Bell fighters, who were huddled together in a tiny, two-room office, but by the mighty Western Union itself, which had been so arrogant when the encounter began. A committee of three from each side was appointed, and after months of disputation, a treaty of peace was drawn up and signed. By the terms of this treaty the Western Union agreed-- (1) To admit that Bell was the original inventor. (2) To admit that his patents were valid. (3) To retire from the telephone business. The Bell Company, in return for this surrender, agreed-- (1) To buy the Western Union telephone system. (2) To pay the Western Union a royalty of twenty per cent on all telephone rentals. (3) To keep out of the telegraph business. This agreement, which was to remain in force for seventeen years, was a master-stroke of diplomacy on the part of the Bell Company. It was the Magna Charta of the telephone. It transformed a giant competitor into a friend. It added to the Bell System fifty-six thousand telephones in fifty-five cities. And it swung the valiant little company up to such a pinnacle of prosperity that its stock went skyrocketing until it touched one thousand dollars a share. The Western Union had lost its case, for several very simple reasons: It had tried to operate a telephone system on telegraphic lines, a plan that has invariably been unsuccessful, it had a low idea of the possibilities of the telephone business; and its already busy agents had little time or knowledge or enthusiasm to give to the new enterprise. With all its power, it found itself outfought by this compact body of picked men, who were young, zealous, well-handled, and protected by a most invulnerable patent. The Bell Telephone now took its place with the Telegraph, the Railroad, the Steamboat, the Harvester, and the other necessities of a civilized country. Its pioneer days were over. There was no more ridicule and incredulity. Every one knew that the Bell people had whipped the Western Union, and hastened to join in the grand Te Deum of applause. Within five months from the signing of the agreement, there had to be a reorganization; and the American Bell Telephone Company was created, with six million dollars capital. In the following year, 1881, twelve hundred new towns and cities were marked on the telephone map, and the first dividends were paid--$178,500. And in 1882 there came such a telephone boom that the Bell System was multiplied by two, with more than a million dollars of gross earnings. At this point all the earliest pioneers of the telephone, except Vail, pass out of its history. Thomas Sanders sold his stock for somewhat less than a million dollars, and presently lost most of it in a Colorado gold mine. His mother, who had been so good a friend to Bell, had her fortune doubled. Gardiner G. Hubbard withdrew from business life, and as it was impossible for a man of his ardent temperament to be idle, he plunged into the National Geographical Society. He was a Colonel Sellers whose dream of millions (for the telephone) had come true; and when he died, in 1897, he was rich both in money and in the affection of his friends. Charles Williams, in whose workshop the first telephones were made, sold his factory to the Bell Company in 1881 for more money than he had ever expected to possess. Thomas A. Watson resigned at the same time, finding himself no longer a wage-worker but a millionaire. Several years later he established a shipbuilding plant near Boston, which grew until it employed four thousand workmen and had built half a dozen warships for the United States Navy. As for Bell, the first cause of the telephone business, he did what a true scientific Bohemian might have been expected to do; he gave all his stock to his bride on their marriage-day and resumed his work as an instructor of deaf-mutes. Few kings, if any, had ever given so rich a wedding present; and certainly no one in any country ever obtained and tossed aside an immense fortune as incidentally as did Bell. When the Bell Company offered him a salary of ten thousand dollars a year to remain its chief inventor, he refused the offer cheerfully on the ground that he could not "invent to order." In 1880, the French Government gave him the Volta Prize of fifty thousand francs and the Cross of the Legion of Honor. He has had many honors since then, and many interests. He has been for thirty years one of the most brilliant and picturesque personalities in American public life. But none of his later achievements can in any degree compare with what he did in a cellar in Salem, at twenty-eight years of age. They had all become rich, these first friends of the telephone, but not fabulously so. There was not at that time, nor has there been since, any one who became a multimillionaire by the sale of telephone service. If the Bell Company had sold its stock at the highest price reached, in 1880, it would have received less than nine million dollars--a huge sum, but not too much to pay for the invention of the telephone and the building up of a new art and a new industry. It was not as much as the value of the eggs laid during the last twelve months by the hens of Iowa. But, as may be imagined, when the news of the Western Union agreement became known, the story of the telephone became a fairy tale of success. Theodore Vail was given a banquet by his old-time friends in the Washington postal service, and toasted as "the Monte Cristo of the Telephone." It was said that the actual cost of the Bell plant was only one-twenty-fifth of its capital, and that every four cents of investment had thus become a dollar. Even Jay Gould, carried beyond his usual caution by these stories, ran up to New Haven and bought its telephone company, only to find out later that its earnings were less than its expenses. Much to the bewilderment of the Bell Company, it soon learned that the troubles of wealth are as numerous as those of poverty. It was beset by a throng of promoters and stock-jobbers, who fell upon it and upon the public like a swarm of seventeen-year locusts. In three years, one hundred and twenty-five competing companies were started, in open defiance of the Bell patents. The main object of these companies was not, like that of the Western Union, to do a legitimate telephone business, but to sell stock to the public. The face value of their stock was $225,000,000, although few of them ever sent a message. One company of unusual impertinence, without money or patents, had capitalized its audacity at $15,000,000. How to HOLD the business that had been established--that was now the problem. None of the Bell partners had been mere stock-jobbers. At one time they had even taken a pledge not to sell any of their stock to outsiders. They had financed their company in a most honest and simple way; and they were desperately opposed to the financial banditti whose purpose was to transform the telephone business into a cheat and a gamble. At first, having held their own against the Western Union, they expected to make short work of the stock-jobbers. But it was a vain hope. These bogus companies, they found, did not fight in the open, as the Western Union had done. All manner of injurious rumors were presently set afloat concerning the Bell patent. Other inventors--some of them honest men, and some shameless pretenders--were brought forward with strangely concocted tales of prior invention. The Granger movement was at that time a strong political factor in the Middle West, and its blind fear of patents and "monopolies" was turned aggressively against the Bell Company. A few Senators and legitimate capitalists were lifted up as the figureheads of the crusade. And a loud hue-and-cry was raised in the newspapers against "high rates and monopoly" to distract the minds of the people from the real issue of legitimate business versus stock-company bubbles. The most plausible and persistent of all the various inventors who snatched at Bell's laurels, was Elisha Gray. He refused to abide by the adverse decision of the court. Several years after his defeat, he came forward with new weapons and new methods of attack. He became more hostile and irreconcilable; and until his death, in 1901, never renounced his claim to be the original inventor of the telephone. The reason for this persistence is very evident. Gray was a professional inventor, a highly competent man who had begun his career as a blacksmith's apprentice, and risen to be a professor of Oberlin. He made, during his lifetime, over five million dollars by his patents. In 1874, he and Bell were running a neck-and-neck race to see who could first invent a musical telegraph--when, presto! Bell suddenly turned aside, because of his acoustical knowledge, and invented the telephone, while Gray kept straight ahead. Like all others who were in quest of a better telegraph instrument, Gray had glimmerings of the possibility of sending speech by wire, and by one of the strangest of coincidences he filed a caveat on the subject on the SAME DAY that Bell filed the application for a patent. Bell had arrived first. As the record book shows, the fifth entry on that day was: "A. G. Bell, $15"; and the thirty-ninth entry was "E. Gray, $10." There was a vast difference between Gray's caveat and Bell's application. A caveat is a declaration that the writer has NOT invented a thing, but believes that he is about to do so; while an APPLICATION is a declaration that the writer has already perfected the invention. But Gray could never forget that he had seemed to be, for a time, so close to the golden prize; and seven years after he had been set aside by the Western Union agreement, he reappeared with claims that had grown larger and more definite. When all the evidence in the various Gray lawsuits is sifted out, there appear to have been three distinctly different Grays: first, Gray the SCOFFER, who examined Bell's telephone at the Centennial and said it was "nothing but the old lover's telegraph. It is impossible to make a practical speaking telephone on the principle shown by Professor Bell.... The currents are too feeble"; second, Gray the CONVERT, who wrote frankly to Bell in 1877, "I do not claim the credit of inventing it"; and third, Gray the CLAIMANT, who endeavored to prove in 1886 that he was the original inventor. His real position in the matter was once well and wittily described by his partner, Enos M. Barton, who said: "Of all the men who DIDN'T invent the telephone, Gray was the nearest." It is now clearly seen that the telephone owes nothing to Gray. There are no Gray telephones in use in any country. Even Gray himself, as he admitted in court, failed when he tried to make a telephone on the lines laid down in his caveat. The final word on the whole matter was recently spoken by George C. Maynard, who established the telephone business in the city of Washington. Said Mr. Maynard: "Mr. Gray was an intimate and valued friend of mine, but it is no disrespect to his memory to say that on some points involved in the telephone matter, he was mistaken. No subject was ever so thoroughly investigated as the invention of the speaking telephone. No patent has ever been submitted to such determined assault from every direction as Bell's; and no inventor has ever been more completely vindicated. Bell was the first inventor, and Gray was not." After Gray, the weightiest challenger who came against Bell was Professor Amos E. Dolbear, of Tufts College. He, like Gray, had written a letter of applause to Bell in 1877. "I congratulate you, sir," he said, "upon your very great invention, and I hope to see it supplant all forms of existing telegraphs, and that you will be successful in obtaining the wealth and honor which is your due." But one year later, Dolbear came to view with an opposition telephone. It was not an imitation of Bell's, he insisted, but an improvement upon an electrical device made by a German named Philip Reis, in 1861. Thus there appeared upon the scene the so-called "Reis telephone," which was not a telephone at all, in any practical sense, but which served well enough for nine years or more as a weapon to use against the Bell patents. Poor Philip Reis himself, the son of a baker in Frankfort, Germany, had hoped to make a telephone, but he had failed. His machine was operated by a "make-and-break" current, and so could not carry the infinitely delicate vibrations made by the human voice. It could transmit the pitch of a sound, but not the QUALITY. At its best, it could carry a tune, but never at any time a spoken sentence. Reis, in his later years, realized that his machine could never be used for the transmission of conversation; and in a letter to a friend he tells of a code of signals that he has invented. Bell had once, during his three years of experimenting, made a Reis machine, although at that time he had not seen one. But he soon threw it aside, as of no practical value. As a teacher of acoustics, Bell knew that the one indispensable requirement of a telephone is that it shall transmit the WHOLE of a sound, and not merely the pitch of it. Such scientists as Lord Kelvin, Joseph Henry, and Edison had seen the little Reis instrument years before Bell invented the telephone; but they regarded it as a mere musical toy. It was "not in any sense a speaking telephone," said Lord Kelvin. And Edison, when trying to put the Reis machine in the most favorable light, admitted humorously that when he used a Reis transmitter he generally "knew what was coming; and knowing what was coming, even a Reis transmitter, pure and simple, reproduces sounds which seem almost like that which was being transmitted; but when the man at the other end did not know what was coming, it was very seldom that any word was recognized." In the course of the Dolbear lawsuit, a Reis machine was brought into court, and created much amusement. It was able to squeak, but not to speak. Experts and professors wrestled with it in vain. It refused to transmit one intelligible sentence. "It CAN speak, but it WON'T," explained one of Dolbear's lawyers. It is now generally known that while a Reis machine, when clogged and out of order, would transmit a word or two in an imperfect way, it was built on wrong lines. It was no more a telephone than a wagon is a sleigh, even though it is possible to chain the wheels and make them slide for a foot or two. Said Judge Lowell, in rendering his famous decision: "A century of Reis would never have produced a speaking telephone by mere improvement of construction. It was left for Bell to discover that the failure was due not to workmanship but to the principle which was adopted as the basis of what had to be done. ... Bell discovered a new art--that of transmitting speech by electricity, and his claim is not as broad as his invention.... To follow Reis is to fail; but to follow Bell is to succeed." After the victory over Dolbear, the Bell stock went soaring skywards; and the higher it went, the greater were the number of infringers and blowers of stock bubbles. To bait the Bell Company became almost a national sport. Any sort of claimant, with any sort of wild tale of prior invention, could find a speculator to support him. On they came, a motley array, "some in rags, some on nags, and some in velvet gowns." One of them claimed to have done wonders with an iron hoop and a file in 1867; a second had a marvellous table with glass legs; a third swore that he had made a telephone in 1860, but did not know what it was until he saw Bell's patent; and a fourth told a vivid story of having heard a bullfrog croak via a telegraph wire which was strung into a certain cellar in Racine, in 1851. This comic opera phase came to a head in the famous Drawbaugh case, which lasted for nearly four years, and filled ten thousand pages with its evidence. Having failed on Reis, the German, the opponents of Bell now brought forward an American inventor named Daniel Drawbaugh, and opened up a noisy newspaper campaign. To secure public sympathy for Drawbaugh, it was said that he had invented a complete telephone and switchboard before 1876, but was in such "utter and abject poverty" that he could not get himself a patent. Five hundred witnesses were examined; and such a general turmoil was aroused that the Bell lawyers were compelled to take the attack seriously, and to fight back with every pound of ammunition they possessed. The fact about Drawbaugh is that he was a mechanic in a country village near Harrisburg, Pennsylvania. He was ingenious but not inventive; and loved to display his mechanical skill before the farmers and villagers. He was a subscriber to The Scientific American; and it had become the fixed habit of his life to copy other people's inventions and exhibit them as his own. He was a trailer of inventors. More than forty instances of this imitative habit were shown at the trial, and he was severely scored by the judge, who accused him of "deliberately falsifying the facts." His ruling passion of imitation, apparently, was not diminished by the loss of his telephone claims, as he came to public view again in 1903 as a trailer of Marconi. Drawbaugh's defeat sent the Bell stock up once more, and brought on a Xerxes' army of opposition which called itself the "Overland Company." Having learned that no one claim-ant could beat Bell in the courts, this company massed the losers together and came forward with a scrap-basket full of patents. Several powerful capitalists undertook to pay the expenses of this adventure. Wires were strung; stock was sold; and the enterprise looked for a time so genuine that when the Bell lawyers asked for an injunction against it, they were refused. This was as hard a blow as the Bell people received in their eleven years of litigation; and the Bell stock tumbled thirty-five points in a few days. Infringing companies sprang up like gourds in the night. And all went merrily with the promoters until the Overland Company was thrown out of court, as having no evidence, except "the refuse and dregs of former cases--the heel-taps found in the glasses at the end of the frolic." But even after this defeat for the claimants, the frolic was not wholly ended. They next planned to get through politics what they could not get through law; they induced the Government to bring suit for the annulment of the Bell patents. It was a bold and desperate move, and enabled the promoters of paper companies to sell stock for several years longer. The whole dispute was re-opened, from Gray to Drawbaugh. Every battle was re-fought; and in the end, of course, the Government officials learned that they were being used to pull telephone chestnuts out of the fire. The case was allowed to die a natural death, and was informally dropped in 1896. In all, the Bell Company fought out thirteen lawsuits that were of national interest, and five that were carried to the Supreme Court in Washington. It fought out five hundred and eighty-seven other lawsuits of various natures; and with the exception of two trivial contract suits, IT NEVER LOST A CASE. Its experience is an unanswerable indictment of our system of protecting inventors. No inventor had ever a clearer title than Bell. The Patent Office itself, in 1884, made an eighteen-months' investigation of all telephone patents, and reported: "It is to Bell that the world owes the possession of the speaking telephone." Yet his patent was continuously under fire, and never at any time secure. Stock companies whose paper capital totalled more than $500,000,000 were organized to break it down; and from first to last the success of the telephone was based much less upon the monopoly of patents than upon the building up of a well organized business. Fortunately for Bell and the men who upheld him, they were defended by two master-lawyers who have seldom, if ever, had an equal for team work and efficiency--Chauncy Smith and James J. Storrow. These two men were marvellously well mated. Smith was an old-fashioned attorney of the Websterian sort, dignified, ponderous, and impressive. By 1878, when he came in to defend the little Bell Company against the towering Western Union, Smith had become the most noted patent lawyer in Boston. He was a large, thick-set man, a reminder of Benjamin Franklin, with clean-shaven face, long hair curling at the ends, frock coat, high collar, and beaver hat. Storrow, on the contrary, was a small man, quiet in manner, conversational in argument, and an encyclopedia of definite information. He was so thorough that, when he became a Bell lawyer, he first spent an entire summer at his country home in Petersham, studying the laws of physics and electricity. He was never in the slightest degree spectacular. Once only, during the eleven years of litigation, did he lose control of his temper. He was attacking the credibility of a witness whom he had put on the stand, but who had been tampered with by the opposition lawyers. "But this man is your own witness," protested the lawyers. "Yes," shouted the usually soft-speaking Storrow; "he WAS my witness, but now he is YOUR LIAR." The efficiency of these two men was greatly increased by a third--Thomas D. Lockwood, who was chosen by Vail in 1879 to establish a Patent Department. Two years before, Lockwood had heard Bell lecture in Chickering Hall, New York, and was a "doubting Thomas." But a closer study of the telephone transformed him into an enthusiast. Having a memory like a filing system, and a knack for invention, Lockwood was well fitted to create such a department. He was a man born for the place. And he has seen the number of electrical patents grow from a few hundred in 1878 to eighty thousand in 1910. These three men were the defenders of the Bell patents. As Vail built up the young telephone business, they held it from being torn to shreds in an orgy of speculative competition. Smith prepared the comprehensive plan of defence. By his sagacity and experience he was enabled to mark out the general principles upon which Bell had a right to stand. Usually, he closed the case, and he was immensely effective as he would declaim, in his deep voice: "I submit, Your Honor, that the literature of the world does not afford a passage which states how the human voice can be electrically transmitted, previous to the patent of Mr. Bell." His death, like his life, was dramatic. He was on his feet in the courtroom, battling against an infringer, when, in the middle of a sentence, he fell to the floor, overcome by sickness and the responsibilities he had carried for twelve years. Storrow, in a different way, was fully as indispensable as Smith. It was he who built up the superstructure of the Bell defence. He was a master of details. His brain was keen and incisive; and some of his briefs will be studied as long as the art of telephony exists. He might fairly have been compared, in action, to a rapid-firing Gatling gun; while Smith was a hundred-ton cannon, and Lockwood was the maker of the ammunition. Smith and Storrow had three main arguments that never were, and never could be, answered. Fifty or more of the most eminent lawyers of that day tried to demolish these arguments, and failed. The first was Bell's clear, straightforward story of HOW HE DID IT, which rebuked and confounded the mob of pretenders. The second was the historical fact that the most eminent electrical scientists of Europe and America had seen Bell's telephone at the Centennial and had declared it to be NEW--"not only new but marvellous," said Tyndall. And the third was the very significant fact that no one challenged Bell's claim to be the original inventor of the telephone until his patent was seventeen months old. The patent itself, too, was a remarkable document. It was a Gibraltar of security to the Bell Company. For eleven years it was attacked from all sides, and never dented. It covered an entire art, yet it was sustained during its whole lifetime. Printed in full, it would make ten pages of this book; but the core of it is in the last sentence: "The method of, and apparatus for, transmitting vocal or other sounds telegraphically, by causing electrical undulations, similar in form to the vibrations of the air accompanying the said vocal or other sounds." These words expressed an idea that had never been written before. It could not be evaded or overcome. There were only thirty-two words, but in six years these words represented an investment of a million dollars apiece. Now that the clamor of this great patent war has died away, it is evident that Bell received no more credit and no more reward than he deserved. There was no telephone until he made one, and since he made one, no one has found out any other way. Hundreds of clever men have been trying for more than thirty years to outrival Bell, and yet every telephone in the world is still made on the plan that Bell discovered. No inventor who preceded Bell did more, in the invention of the telephone, than to help Bell indirectly, in the same way that Fra Mauro and Toscanelli helped in the discovery of America by making the map and chart that were used by Columbus. Bell was helped by his father, who taught him the laws of acoustics; by Helmholtz, who taught him the influence of magnets upon sound vibrations; by Koenig and Leon Scott, who taught him the infinite variety of these vibrations; by Dr. Clarence J. Blake, who gave him a human ear for his experiments; and by Joseph Henry and Sir Charles Wheatstone, who encouraged him to persevere. In a still more indirect way, he was helped by Morse's invention of the telegraph; by Faraday's discovery of the phenomena of magnetic induction; by Sturgeon's first electro-magnet; and by Volta's electric battery. All that scientists had achieved, from Galileo and Newton to Franklin and Simon Newcomb, helped Bell in a general way, by creating a scientific atmosphere and habit of thought. But in the actual making of the telephone, there was no one with Bell nor before him. He invented it first, and alone. CHAPTER IV. THE DEVELOPMENT OF THE ART Four wire-using businesses were already in the field when the telephone was born: the fire-alarm, burglar-alarm, telegraph, and messenger-boy service; and at first, as might have been expected, the humble little telephone was huddled in with these businesses as a sort of poor relation. To the general public, it was a mere scientific toy; but there were a few men, not many, in these wire-stringing trades, who saw a glimmering chance of creating a telephone business. They put telephones on the wires that were then in use. As these became popular, they added others. Each of their customers wished to be able to talk to every one else. And so, having undertaken to give telephone service, they presently found themselves battling with the most intricate and baffling engineering problem of modern times--the construction around the tele-phone of such a mechanism as would bring it into universal service. The first of these men was Thomas A. Watson, the young mechanic who had been hired as Bell's helper. He began a work that to-day requires an army of twenty-six thousand people. He was for a couple of years the total engineering and manufacturing department of the telephone business, and by 1880 had taken out sixty patents for his own suggestions. It was Watson who took the telephone as Bell had made it, really a toy, with its diaphragm so delicate that a warm breath would put it out of order, and toughened it into a more rugged machine. Bell had used a disc of fragile gold-beaters' skin with a patch of sheet-iron glued to the centre. He could not believe, for a time, that a disc of all-iron would vibrate under the slight influence of a spoken word. But he and Watson noticed that when the patch was bigger the talking was better, and presently they threw away the gold-beaters' skin and used the iron alone. Also, it was Watson who spent months experimenting with all sorts and sizes of iron discs, so as to get the one that would best convey the sound. If the iron was too thick, he discovered, the voice was shrilled into a Punch-and-Judy squeal; and if it was too thin, the voice became a hollow and sepulchral groan, as if the speaker had his head in a barrel. Other months, too, were spent in finding out the proper size and shape for the air cavity in front of the disc. And so, after the telephone had been perfected, IN PRINCIPLE, a full year was required to lift it out of the class of scientific toys, and another year or two to present it properly to the business world. Until 1878 all Bell telephone apparatus was made by Watson in Charles Williams's little shop in Court Street, Boston--a building long since transformed into a five-cent theatre. But the business soon grew too big for the shop. Orders fell five weeks behind. Agents stormed and fretted. Some action had to be taken quickly, so licenses were given to four other manufacturers to make bells, switchboards, and so forth. By this time the Western Electric Company of Chicago had begun to make the infringing Gray-Edison telephones for the Western Union, so that there were soon six groups of mechanics puzzling their wits over the new talk-machinery. By 1880 there was plenty of telephonic apparatus being made, but in too many different varieties. Not all the summer gowns of that year presented more styles and fancies. The next step, if there was to be any degree of uniformity, was plainly to buy and consolidate these six companies; and by 1881 Vail had done this. It was the first merger in telephone history. It was a step of immense importance. Had it not been taken, the telephone business would have been torn into fragments by the civil wars between rival inventors. From this time the Western Electric became the headquarters of telephonic apparatus. It was the Big Shop, all roads led to it. No matter where a new idea was born, sooner or later it came knocking at the door of the Western Electric to receive a material body. Here were the skilled workmen who became the hands of the telephone business. And here, too, were many of the ablest inventors and engineers, who did most to develop the cables and switchboards of to-day. In Boston, Watson had resigned in 1882, and in his place, a year or two later stood a timely new arrival named E. T. Gilliland. This really notable man was a friend in need to the telephone. He had been a manufacturer of electrical apparatus in Indianapolis, until Vail's policy of consolidation drew him into the central group of pioneers and pathfinders. For five years Gilliland led the way as a developer of better and cheaper equipment. He made the best of a most difficult situation. He was so handy, so resourceful, that he invariably found a way to unravel the mechanical tangles that perplexed the first telephone agents, and this, too, without compelling them to spend large sums of capital. He took the ideas and apparatus that were then in existence, and used them to carry the telephone business through the most critical period of its life, when there was little time or money to risk on experiments. He took the peg switchboard of the telegraph, for in-stance, and developed it to its highest point, to a point that was not even imagined possible by any one else. It was the most practical and complete switchboard of its day, and held the field against all comers until it was superseded by the modern type of board, vastly more elaborate and expensive. By 1884, gathered around Gilliland in Boston and the Western Electric in Chicago, there came to be a group of mechanics and high-school graduates, very young men, mostly, who had no reputations to lose; and who, partly for a living and mainly for a lark, plunged into the difficulties of this new business that had at that time little history and less prestige. These young adventurers, most of whom are still alive, became the makers of industrial history. They were unquestionably the founders of the present science of telephone engineering. The problem that they dashed at so lightheartedly was much larger than any of them imagined. It was a Gibraltar of impossibilities. It was on the face of it a fantastic nightmare of a task--to weave such a web of wires, with interlocking centres, as would put any one telephone in touch with every other. There was no help for them in books or colleges. Watson, who had acquired a little knowledge, had become a shipbuilder. Electrical engineering, as a profession, was unborn. And as for their telegraphic experience, while it certainly helped them for a time, it started them in the wrong direction and led them to do many things which had afterwards to be undone. The peculiar electric current that these young pathfinders had to deal with is perhaps the quickest, feeblest, and most elusive force in the world. It is so amazing a thing that any description of it seems irrational. It is as gentle as a touch of a baby sunbeam, and as swift as the lightning flash. It is so small that the electric current of a single incandescent lamp is greater 500,000,000 times. Cool a spoonful of hot water just one degree, and the energy set free by the cooling will operate a telephone for ten thousand years. Catch the falling tear-drop of a child, and there will be sufficient water-power to carry a spoken message from one city to another. Such is the tiny Genie of the Wire that had to be protected and trained into obedience. It was the most defenceless of all electric sprites, and it had so many enemies. Enemies! The world was populous with its enemies. There was the lightning, its elder brother, striking at it with murderous blows. There were the telegraphic and light-and-power currents, its strong and malicious cousins, chasing and assaulting it whenever it ventured too near. There were rain and sleet and snow and every sort of moisture, lying in wait to abduct it. There were rivers and trees and flecks of dust. It seemed as if all the known and unknown agencies of nature were in conspiracy to thwart or annihilate this gentle little messenger who had been conjured into life by the wizardry of Alexander Graham Bell. All that these young men had received from Bell and Watson was that part of the telephone that we call the receiver. This was practically the sum total of Bell's invention, and remains to-day as he made it. It was then, and is yet, the most sensitive instrument that has ever been put to general use in any country. It opened up a new world of sound. It would echo the tramp of a fly that walked across a table, or repeat in New Orleans the prattle of a child in New York. This was what the young men received, and this was all. There were no switchboards of any account, no cables of any value, no wires that were in any sense adequate, no theory of tests or signals, no exchanges, NO TELEPHONE SYSTEM OF ANY SORT WHATEVER. As for Bell's first telephone lines, they were as simple as clothes-lines. Each short little wire stood by itself, with one instrument at each end. There were no operators, switchboards, or exchanges. But there had now come a time when more than two persons wanted to be in the same conversational group. This was a larger use of the telephone; and while Bell himself had foreseen it, he had not worked out a plan whereby it could be carried out. Here was the new problem, and a most stupendous one--how to link together three telephones, or three hundred, or three thousand, or three million, so that any two of them could be joined at a moment's notice. And that was not all. These young men had not only to battle against mystery and "the powers of the air"; they had not only to protect their tiny electric messenger, and to create a system of wire highways along which he could run up and down safely; they had to do more. They had to make this system so simple and fool-proof that every one--every one except the deaf and dumb--could use it without any previous experience. They had to educate Bell's Genie of the Wire so that he would not only obey his masters, but anybody--anybody who could speak to him in any language. No doubt, if the young men had stopped to consider their life-work as a whole, some of them might have turned back. But they had no time to philosophize. They were like the boy who learns how to swim by being pushed into deep water. Once the telephone business was started, it had to be kept going; and as it grew, there came one after another a series of congestions. Two courses were open; either the business had to be kept down to suit the apparatus, or the apparatus had to be developed to keep pace with the business. The telephone men, most of them, at least, chose development; and the brilliant inventions that afterwards made some of them famous were compelled by sheer necessity and desperation. The first notable improvement upon Bell's invention was the making of the transmitter, in 1877, by Emile Berliner. This, too, was a romance. Berliner, as a poor German youth of nineteen, had landed in Castle Garden in 1870 to seek his fortune. He got a job as "a sort of bottle-washer at six dollars a week," he says, in a chemical shop in New York. At nights he studied science in the free classes of Cooper Union. Then a druggist named Engel gave him a copy of Muller's book on physics, which was precisely the stimulus needed by his creative brain. In 1876 he was fascinated by the telephone, and set out to construct one on a different plan. Several months later he had succeeded and was overjoyed to receive his first patent for a telephone transmitter. He had by this time climbed up from his bottle-washing to be a clerk in a drygoods store in Washington; but he was still poor and as unpractical as most inventors. Joseph Henry, the Sage of the American scientific world, was his friend, though too old to give him any help. Consequently, when Edison, two weeks later, also invented a transmitter, the prior claim of Berliner was for a time wholly ignored. Later the Bell Company bought Berliner's patent and took up his side of the case. There was a seemingly endless succession of delays--fourteen years of the most vexatious delays--until finally the Supreme Court of the United States ruled that Berliner, and not Edison, was the original inventor of the transmitter. From first to last, the transmitter has been the product of several minds. Its basic idea is the varying of the electric current by varying the pressure between two points. Bell unquestionably suggested it in his famous patent, when he wrote of "increasing and diminishing the resistance." Berliner was the first actually to construct one. Edison greatly improved it by using soft carbon instead of a steel point. A Kentucky professor, David E. Hughes, started a new line of development by adapting a Bell telephone into a "microphone," a fantastic little instrument that would detect the noise made by a fly in walking across a table. Francis Blake, of Boston, changed a microphone into a practical transmitter. The Rev. Henry Hunnings, an English clergyman, hit upon the happy idea of using carbon in the form of small granules. And one of the Bell experts, named White, improved the Hunnings transmitter into its present shape. Both transmitter and receiver seem now to be as complete an artificial tongue and ear as human ingenuity can make them. They have persistently grown more elaborate, until today a telephone set, as it stands on a desk, contains as many as one hundred and thirty separate pieces, as well as a saltspoonful of glistening granules of carbon. Next after the transmitter came the problem of the MYSTERIOUS NOISES. This was, perhaps, the most weird and mystifying of all the telephone problems. The fact was that the telephone had brought within hearing distance a new wonder-world of sound. All wires at that time were single, and ran into the earth at each end, making what was called a "grounded circuit." And this connection with the earth, which is really a big magnet, caused all manner of strange and uncouth noises on the telephone wires. Noises! Such a jangle of meaningless noises had never been heard by human ears. There were spluttering and bubbling, jerking and rasping, whistling and screaming. There were the rustling of leaves, the croaking of frogs, the hissing of steam, and the flapping of birds' wings. There were clicks from telegraph wires, scraps of talk from other telephones, and curious little squeals that were unlike any known sound. The lines running east and west were noisier than the lines running north and south. The night was noisier than the day, and at the ghostly hour of midnight, for what strange reason no one knows, the babel was at its height. Watson, who had a fanciful mind, suggested that perhaps these sounds were signals from the inhabitants of Mars or some other sociable planet. But the matter-of-fact young telephonists agreed to lay the blame on "induction"--a hazy word which usually meant the natural meddlesomeness of electricity. Whatever else the mysterious noises were, they were a nuisance. The poor little telephone business was plagued almost out of its senses. It was like a dog with a tin can tied to its tail. No matter where it went, it was pursued by this unearthly clatter. "We were ashamed to present our bills," said A. A. Adee, one of the first agents; "for no matter how plainly a man talked into his telephone, his language was apt to sound like Choctaw at the other end of the line." All manner of devices were solemnly tried to hush the wires, and each one usually proved to be as futile as an incantation. What was to be done? Step by step the telephone men were driven back. They were beaten. There was no way to silence these noises. Reluctantly, they agreed that the only way was to pull up the ends of each wire from the tainted earth, and join them by a second wire. This was the "metallic circuit" idea. It meant an appalling increase in the use of wire. It would compel the rebuild-ing of the switchboards and the invention of new signal systems. But it was inevitable; and in 1883, while the dispute about it was in full blast, one of the young men quietly slipped it into use on a new line between Boston and Providence. The effect was magical. "At last," said the delighted manager, "we have a perfectly quiet line." This young man, a small, slim youth who was twenty-two years old and looked younger, was no other than J. J. Carty, now the first of telephone engineers and almost the creator of his profession. Three years earlier he had timidly asked for a job as operator in the Boston exchange, at five dollars a week, and had shown such an aptitude for the work that he was soon made one of the captains. At thirty years of age he became a central figure in the development of the art of telephony. What Carty has done is known by telephone men in all countries; but the story of Carty himself--who he is, and why--is new. First of all, he is Irish, pure Irish. His father had left Ireland as a boy in 1825. During the Civil War his father made guns in the city of Cambridge, where young John Joseph was born; and afterwards he made bells for church steeples. He was instinctively a mechanic and proud of his calling. He could tell the weight of a bell from the sound of it. Moses G. Farmer, the electrical inventor, and Howe, the creator of the sewing-machine, were his friends. At five years of age, little John J. Carty was taken by his father to the shop where the bells were made, and he was profoundly impressed by the magical strength of a big magnet, that picked up heavy weights as though they were feathers. At the high school his favorite study was physics; and for a time he and another boy named Rolfe--now a distinguished man of science--carried on electrical experiments of their own in the cellar of the Rolfe house. Here they had a "Tom Thumb" telegraph, a telephone which they had ventured to improve, and a hopeless tangle of wires. Whenever they could afford to buy more wires and batteries, they went to a near-by store which supplied electrical apparatus to the professors and students of Harvard. This store, with its workshop in the rear, seemed to the two boys a veritable wonderland; and when Carty, a youth of eighteen, was compelled to leave school because of his bad eyesight, he ran at once and secured the glorious job of being boy-of-all-work in this store of wonders. So, when he became an operator in the Boston telephone exchange, a year later, he had already developed to a remarkable degree his natural genius for telephony. Since then, Carty and the telephone business have grown up together, he always a little distance in advance. No other man has touched the apparatus of telephony at so many points. He fought down the flimsy, clumsy methods, which led from one snarl to another. He found out how to do with wires what Dickens did with words. "Let us do it right, boys, and then we won't have any bad dreams"--this has been his motif. And, as the crown and climax of his work, he mapped out the profession of telephone engineering on the widest and most comprehensive lines. In Carty, the engineer evolved into the educator. His end of the American Telephone and Telegraph Company became the University of the Telephone. He was himself a student by disposition, with a special taste for the writings of Faraday, the forerunner; Tyndall, the expounder; and Spencer, the philosopher. And in 1890, he gathered around him a winnowed group of college graduates--he has sixty of them on his staff to-day--so that he might bequeath to the telephone an engineering corps of loyal and efficient men. The next problem that faced the young men of the telephone, as soon as they had escaped from the clamor of the mysterious noises, was the necessity of taking down the wires in the city streets and putting them underground. At first, they had strung the wires on poles and roof-tops. They had done this, not because it was cheap, but because it was the only possible way, so far as any one knew in that kindergarten period. A telephone wire required the daintiest of handling. To bury it was to smother it, to make it dull or perhaps entirely useless. But now that the number of wires had swollen from hundreds to thousands, the overhead method had been outgrown. Some streets in the larger cities had become black with wires. Poles had risen to fifty feet in height, then sixty--seventy--eighty. Finally the highest of all pole lines was built along West Street, New York--every pole a towering Norway pine, with its top ninety feet above the roadway, and carrying thirty cross-arms and three hundred wires. From poles the wires soon overflowed to housetops, until in New York alone they had overspread eleven thousand roofs. These roofs had to be kept in repair, and their chimneys were the deadly enemies of the iron wires. Many a wire, in less than two or three years, was withered to the merest shred of rust. As if these troubles were not enough, there were the storms of winter, which might wipe out a year's revenue in a single day. The sleet storms were the worst. Wires were weighted down with ice, often three pounds of ice per foot of wire. And so, what with sleet, and corrosion, and the cost of roof-repairing, and the lack of room for more wires, the telephone men were between the devil and the deep sea--between the urgent necessity of burying their wires, and the inexorable fact that they did not know how to do it. Fortunately, by the time that this problem arrived, the telephone business was fairly well established. It had outgrown its early days of ridicule and incredulity. It was paying wages and salaries and even dividends. Evidently it had arrived on the scene in the nick of time--after the telegraph and before the trolleys and electric lights. Had it been born ten years later, it might not have been able to survive. So delicate a thing as a baby telephone could scarcely have protected itself against the powerful currents of electricity that came into general use in 1886, if it had not first found out a way of hiding safely underground. The first declaration in favor of an underground system was made by the Boston company in 1880. "It may be expedient to place our entire system underground," said the sorely perplexed manager, "whenever a practicable method is found of accomplishing: it." All manner of theories were afloat but Theodore N. Vail, who was usually the man of constructive imagination in emergencies, began in 1882 a series of actual experiments at Attleborough, Massachusetts, to find out exactly what could, and what could not, be done with wires that were buried in the earth. A five-mile trench was dug beside a railway track. The work was done handily and cheaply by the labor-saving plan of hitching a locomotive to a plough. Five ploughs were jerked apart before the work was finished. Then, into this trench were laid wires with every known sort of covering. Most of them, naturally, were wrapped with rubber or gutta-percha, after the fashion of a submarine cable. When all were in place, the willing locomotive was harnessed to a huge wooden drag, which threw the ploughed soil back into the trench and covered the wires a foot deep. It was the most professional cable-laying that any one at that time could do, and it succeeded, not brilliantly, but well enough to encourage the telephone engineers to go ahead. Several weeks later, the first two cables for actual use were laid in Boston and Brooklyn; and in 1883 Engineer J. P. Davis was set to grapple with the Herculean labor of putting a complete underground system in the wire-bound city of New York. This he did in spite of a bombardment of explosions from leaky gas-pipes, and with a woeful lack of experts and standard materials. All manner of makeshifts had to be tried in place of tile ducts, which were not known in 1883. Iron pipe was used at first, then asphalt, concrete, boxes of sand and creosoted wood. As for the wires, they were first wrapped in cotton, and then twisted into cables, usually of a hundred wires each. And to prevent the least taint of moisture, which means sudden death to a telephone current, these cables were invariably soaked in oil. This oil-filled type of cable carried the telephone business safely through half a dozen years. But it was not the final type. It was preliminary only, the best that could be made at that time. Not one is in use to-day. In 1888 Theodore Vail set on foot a second series of experiments, to see if a cable could be made that was better suited as a highway for the delicate electric currents of the telephone. A young engineer named John A. Barrett, who had already made his mark as an expert, by finding a way to twist and transpose the wires, was set apart to tackle this problem. Being an economical Vermonter, Barrett went to work in a little wooden shed in the backyard of a Brooklyn foundry. In this foundry he had seen a unique machine that could be made to mould hot lead around a rope of twisted wires. This was a notable discovery. It meant TIGHT COVERINGS. It meant a victory over that most troublesome of enemies--moisture. Also, it meant that cables could henceforth be made longer, with fewer sleeves and splices, and without the oil, which had always been an unmitigated nuisance. Next, having made the cable tight, Barrett set out to produce it more cheaply and by accident stumbled upon a way to make it immensely more efficient. All wires were at that time wrapped with cotton, and his plan was to find some less costly material that would serve the same purpose. One of his workmen, a Virginian, suggested the use of paper twine, which had been used in the South during the Civil War, when cotton was scarce and expensive. Barrett at once searched the South for paper twine and found it. He bought a barrel of it from a small factory in Richmond, but after a trial it proved to be too flimsy. If such paper could be put on flat, he reasoned, it would be stronger. Just then he heard of an erratic genius who had an invention for winding paper tape on wire for the use of milliners. Paper-wound bonnet-wire! Who could imagine any connection between this and the telephone? Yet this hint was exactly what Barrett needed. He experimented until he had devised a machine that crumpled the paper around the wire, instead of winding it tightly. This was the finishing touch. For a time these paper-wound cables were soaked in oil, but in 1890 Engineer F. A. Pickernell dared to trust to the tightness of the lead sheathing, and laid a "dry core" cable, the first of the modern type, in one of the streets of Philadelphia. This cable was the event of the year. It was not only cheaper. It was the best-talking cable that had ever been harnessed to a telephone. What Barrett had done was soon made clear. By wrapping the wire with loose paper, he had in reality cushioned it with AIR, which is the best possible insulator. Not the paper, but the air in the paper, had improved the cable. More air was added by the omission of the oil. And presently Barrett perceived that he had merely reproduced in a cable, as far as possible, the conditions of the overhead wires, which are separated by nothing but air. By 1896 there were two hundred thousand miles of wire snugly wrapped in paper and lying in leaden caskets beneath the streets of the cities, and to-day there are six million miles of it owned by the affiliated Bell companies. Instead of blackening the streets, the wire nerves of the telephone are now out of sight under the roadway, and twining into the basements of buildings like a new sort of metallic ivy. Some cables are so large that a single spool of cable will weigh twenty-six tons and require a giant truck and a sixteen-horse team to haul it to its resting-place. As many as twelve hundred wires are often bunched into one sheath, and each cable lies loosely in a little duct of its own. It is reached by manholes where it runs under the streets and in little switching-boxes placed at intervals it is frayed out into separate pairs of wires that blossom at length into telephones. Out in the open country there are still the open wires, which in point of talking are the best. In the suburbs of cities there are neat green posts with a single gray cable hung from a heavy wire. Usually, a telephone pole is made from a sixty-year-old tree, a cedar, chestnut, or juniper. It lasts twelve years only, so that the one item of poles is still costing the telephone companies several millions a year. The total number of poles now in the United States, used by telephone and telegraph companies, once covered an area, before they were cut down, as large as the State of Rhode Island. But the highest triumph of wire-laying came when New York swept into the Skyscraper Age, and when hundreds of tall buildings, as high as the fall of the waters of Niagara, grew up like a range of magical cliffs upon the precious rock of Manhattan. Here the work of the telephone engineer has been so well done that although every room in these cliff-buildings has its telephone, there is not a pole in sight, not a cross-arm, not a wire. Nothing but the tip-ends of an immense system are visible. No sooner is a new skyscraper walled and roofed, than the telephones are in place, at once putting the tenants in touch with the rest of the city and the greater part of the United States. In a single one of these monstrous buildings, the Hudson Terminal, there is a cable that runs from basement to roof and ravels out to reach three thousand desks. This mighty geyser of wires is fifty tons in weight and would, if straightened out into a single line, connect New York with Chicago. Yet it is as invisible as the nerves and muscles of a human body. During this evolution of the cable, even the wire itself was being remade. Vail and others had noticed that of all the varieties of wire that were for sale, not one was exactly suitable for a telephone system. The first telephone wire was of galvanized iron, which had at least the primitive virtue of being cheap. Then came steel wire, stronger but less durable. But these wires were noisy and not good conductors of electricity. An ideal telephone wire, they found, must be made of either silver or copper. Silver was out of the question, and copper wire was too soft and weak. It would not carry its own weight. The problem, therefore, was either to make steel wire a better conductor, or to produce a copper wire that would be strong enough. Vail chose the latter, and forthwith gave orders to a Bridgeport manufacturer to begin experiments. A young expert named Thomas B. Doolittle was at once set to work, and presently appeared the first hard-drawn copper wire, made tough-skinned by a fairly simple process. Vail bought thirty pounds of it and scattered it in various parts of the United States, to note the effect upon it of different climates. One length of it may still be seen at the Vail homestead in Lyndonville, Vermont. Then this hard-drawn wire was put to a severe test by being strung between Boston and New York. This line was a brilliant success, and the new wire was hailed with great delight as the ideal servant of the telephone. Since then there has been little trouble with copper wire, except its price. It was four times as good as iron wire, and four times as expensive. Every mile of it, doubled, weighed two hundred pounds and cost thirty dollars. On the long lines, where it had to be as thick as a lead pencil, the expense seemed to be ruinously great. When the first pair of wires was strung between New York and Chicago, for instance, it was found to weigh 870,000 pounds--a full load for a twenty-two-car freight train; and the cost of the bare metal was $130,000. So enormous has been the use of copper wire since then by the telephone companies, that fully one-fourth of all the capital invested in the telephone has gone to the owners of the copper mines. For several years the brains of the telephone men were focussed upon this problem--how to reduce the expenditure on copper. One uncanny device, which would seem to be a mere inventor's fantasy if it had not already saved the telephone companies four million dollars or more, is known as the "phantom circuit." It enables three messages to run at the same time, where only two ran before. A double track of wires is made to carry three talk-trains running abreast, a feat made possible by the whimsical disposition of electricity, and which is utterly inconceivable in railroading. This invention, which is the nearest approach as yet to multiple telephony, was conceived by Jacobs in England and Carty in the United States. But the most copper money has been saved--literally tens of millions of dollars--by persuading thin wires to work as efficiently as thick ones. This has been done by making better transmitters, by insulating the smaller wires with enamel instead of silk, and by placing coils of a certain nature at intervals upon the wires. The invention of this last device startled the telephone men like a flash of lightning out of a blue sky. It came from outside--from the quiet laboratory of a Columbia professor who had arrived in the United States as a young Hungarian immigrant not many years earlier. From this professor, Michael J. Pupin, came the idea of "loading" a telephone line, in such a way as to reinforce the electric current. It enabled a thin wire to carry as far as a thick one, and thus saved as much as forty dollars a wire per mile. As a reward for his cleverness, a shower of gold fell upon Pupin, and made him in an instant as rich as one of the grand-dukes of his native land. It is now a most highly skilled occupation, supporting fully fifteen thousand families, to put the telephone wires in place and protect them against innumerable dangers. This is the profession of the wire chiefs and their men, a corps of human spiders, endlessly spinning threads under streets and above green fields, on the beds of rivers and the slopes of mountains, massing them in cities and fluffing them out among farms and villages. To tell the doings of a wire chief, in the course of his ordinary week's work, would in itself make a lively book of adventures. Even a washerwoman, with one lone, non-electrical clothes-line of a hundred yards to operate, has often enough trouble with it. But the wire chiefs of the Bell telephone have charge of as much wire as would make TWO HUNDRED MILLION CLOTHES-LINES--ten apiece to every family in the United States; and these lines are not punctuated with clothespins, but with the most delicate of electrical instruments. The wire chiefs must detect trouble under a thousand disguises. Perhaps a small boy has thrown a snake across the wires or driven a nail into a cable. Perhaps some self-reliant citizen has moved his own telephone from one room to another. Perhaps a sudden rainstorm has splashed its fatal moisture upon an unwiped joint. Or perhaps a submarine cable has been sat upon by the Lusitania and flattened to death. But no matter what the trouble, a telephone system cannot be stopped for repairs. It cannot be picked up and put into a dry-dock. It must be repaired or improved by a sort of vivisection while it is working. It is an interlocking unit, a living, conscious being, half human and half machine; and an injury in any one place may cause a pain or sickness to its whole vast body. And just as the particles of a human body change every six or seven years, without disturb-ing the body, so the particles of our telephone systems have changed repeatedly without any interruption of traffic. The constant flood of new inventions has necessitated several complete rebuildings. Little or nothing has ever been allowed to wear out. The New York system was rebuilt three times in sixteen years; and many a costly switchboard has gone to the scrap-heap at three or four years of age. What with repairs and inventions and new construction, the various Bell companies have spent at least $425,000,000 in the first ten years of the twentieth century, without hindering for a day the ceaseless torrent of electrical conversation. The crowning glory of a telephone system of to-day is not so much the simple telephone itself, nor the maze and mileage of its cables, but rather the wonderful mechanism of the Switchboard. This is the part that will always remain mysterious to the public. It is seldom seen, and it remains as great a mystery to those who have seen it as to those who have not. Explanations of it are futile. As well might any one expect to learn Sanscrit in half an hour as to understand a switchboard by making a tour of investigation around it. It is not like anything else that either man or Nature has ever made. It defies all metaphors and comparisons. It cannot be shown by photography, not even in moving-pictures, because so much of it is concealed inside its wooden body. And few people, if any, are initiated into its inner mysteries except those who belong to its own cortege of inventors and attendants. A telephone switchboard is a pyramid of inventions. If it is full-grown, it may have two million parts. It may be lit with fifteen thousand tiny electric lamps and nerved with as much wire as would reach from New York to Berlin. It may cost as much as a thousand pianos or as much as three square miles of farms in Indiana. The ten thousand wire hairs of its head are not only numbered, but enswathed in silk, and combed out in so marvellous a way that any one of them can in a flash be linked to any other. Such hair-dressing! Such puffs and braids and ringlet relays! Whoever would learn the utmost that may be done with copper hairs of Titian red, must study the fantastic coiffure of a telephone Switchboard. If there were no switchboard, there would still be telephones, but not a telephone system. To connect five thousand people by telephone requires five thousand wires when the wires run to a switchboard; but without a switchboard there would have to be 12,497,500 wires--4,999 to every telephone. As well might there be a nerve-system without a brain, as a telephone system without a switchboard. If there had been at first two separate companies, one owning the telephone and the other the switchboard, neither could have done the business. Several years before the telephone got a switchboard of its own, it made use of the boards that had been designed for the telegraph. These were as simple as wheelbarrows, and became absurdly inadequate as soon as the telephone business began to grow. Then there came adaptations by the dozen. Every telephone manager became by compulsion an inventor. There was no source of information and each exchange did the best it could. Hundreds of patents were taken out. And by 1884 there had come to be a fairly definite idea of what a telephone switchboard ought to be. The one man who did most to create the switchboard, who has been its devotee for more than thirty years, is a certain modest and little known inventor, still alive and busy, named Charles E. Scribner. Of the nine thousand switchboard patents, Scribner holds six hundred or more. Ever since 1878, when he devised the first "jackknife switch," Scribner has been the wizard of the switchboard. It was he who saw most clearly its requirements. Hundreds of others have helped, but Scribner was the one man who persevered, who never asked for an easier job, and who in the end became the master of his craft. It may go far to explain the peculiar genius of Scribner to say that he was born in 1858, in the year of the laying of the Atlantic Cable; and that his mother was at the time profoundly interested in the work and anxious for its success. His father was a judge in Toledo; but young Scribner showed no aptitude for the tangles of the law. He preferred the tangles of wire and system in miniature, which he and several other boys had built and learned to operate. These boys had a benefactor in an old bachelor named Thomas Bond. He had no special interest in telegraphy. He was a dealer in hides. But he was attracted by the cleverness of the boys and gave them money to buy more wires and more batteries. One day he noticed an invention of young Scribner's--a telegraph repeater. "This may make your fortune," he said, "but no mechanic in Toledo can make a proper model of it for you. You must go to Chicago, where telegraphic apparatus is made." The boy gladly took his advice and went to the Western Electric factory in Chicago. Here he accidentally met Enos M. Barton, the head of the factory. Barton noted that the boy was a genius and offered him a job, which he accepted and has held ever since. Such is the story of the entrance of Charles E. Scribner into the telephone business, where he has been well-nigh indispensable. His monumental work has been the development of the MULTIPLE Switchboard, a much more brain-twisting problem than the building of the Pyramids or the digging of the Panama Canal. The earlier types of switchboard had become too cumbersome by 1885. They were well enough for five hundred wires but not for five thousand. In some exchanges as many as half a dozen operators were necessary to handle a single call; and the clamor and confusion were becoming unbearable. Some handier and quieter way had to be devised, and thus arose the Multiple board. The first crude idea of such a way had sprung to life in the brain of a Chicago man named L. B. Firman, in 1879; but he became a farmer and forsook his invention in its infancy. In the Multiple board, as it grew up under the hands of Scribner, the outgoing wires are duplicated so as to be within reach of every operator. A local call can thus be answered at once by the operator who receives it; and any operator who is overwhelmed by a sudden rush of business can be helped by her companions. Every wire that comes into the board is tasselled out into many ends, and by means of a "busy test," invented by Scribner, only one of these ends can be put into use at a time. The normal limit of such a board is ten thousand wires, and will always remain so, unless a race of long-armed giantesses should appear, who would be able to reach over a greater expanse of board. At present, a business of more than ten thousand lines means a second exchange. The Multiple board was enormously expensive. It grew more and more elaborate until it cost one-third of a million dollars. The telephone men racked their brains to produce something cheaper to take its place, and they failed. The Multiple boards swallowed up capital as a desert swallows water, but THEY SAVED TEN SECONDS ON EVERY CALL. This was an unanswerable argument in their favor, and by 1887 twenty-one of them were in use. Since then, the switchboard has had three or four rebuildings. There has seemed to be no limit to the demands of the public or the fertility of Scribner's brain. Persistent changes were made in the system of signalling. The first signal, used by Bell and Watson, was a tap on the diaphragm with the finger-nail. Soon after-wards came a "buzzer," and then the magneto-electric bell. In 1887 Joseph O'Connell, of Chicago, conceived of the use of tiny electric lights as signals, a brilliant idea, as an electric light makes no noise and can be seen either by night or by day. In 1901, J. J. Carty invented the "bridging bell," a way to put four houses on a single wire, with a different signal for each house. This idea made the "party line" practicable, and at once created a boom in the use of the telephone by enterprising farmers. In 1896 there came a most revolutionary change in switchboards. All things were made new. Instead of individual batteries, one at each telephone, a large common battery was installed in the exchange itself. This meant better signalling and better talking. It reduced the cost of batteries and put them in charge of experts. It established uniformity. It introduced the federal idea into the mechanism of a telephone system. Best of all, it saved FOUR SECONDS ON EVERY CALL. The first of these centralizing switchboards was put in place at Philadelphia; and other cities followed suit as fast as they could afford the expense of rebuilding. Since then, there have come some switchboards that are wholly automatic. Few of these have been put into use, for the reason that a switchboard, like a human body, must be semi-automatic only. To give the most efficient service, there will always need to be an expert to stand between it and the public. As the final result of all these varying changes in switchboards and signals and batteries, there grew up the modern Telephone Exchange. This is the solar plexus of the telephone body. It is the vital spot. It is the home of the switchboard. It is not any one's invention, as the telephone was. It is a growing mechanism that is not yet finished, and may never be; but it has already evolved far enough to be one of the wonders of the electrical world. There is probably no other part of an American city's equipment that is as sensitive and efficient as a telephone exchange. The idea of the exchange is somewhat older than the idea of the telephone itself. There were communication exchanges before the invention of the telephone. Thomas B. Doolittle had one in Bridgeport, using telegraph instruments Thomas B. A. David had one in Pittsburg, using printing-telegraph machines, which required little skill to operate. And William A. Childs had a third, for lawyers only, in New York, which used dials at first and afterwards printing machines. These little exchanges had set out to do the work that is done to-day by the telephone, and they did it after a fashion, in a most crude and expensive way. They helped to prepare the way for the telephone, by building up small constituencies that were ready for the telephone when it arrived. Bell himself was perhaps the first to see the future of the telephone exchange. In a letter written to some English capitalists in 1878, he said: "It is possible to connect every man's house, office or factory with a central station, so as to give him direct communication with his neighbors.... It is conceivable that cables of telephone wires could be laid underground, or suspended overhead, connecting by branch wires with private dwellings, shops, etc., and uniting them through the main cable with a central office." This remarkable prophecy has now become stale reading, as stale as Darwin's "Origin of Species," or Adam Smith's "Wealth of Nations." But at the time that it was written it was a most fanciful dream. When the first infant exchange for telephone service was born in Boston, in 1877, it was the tiny offspring of a burglar-alarm business operated by E. T. Holmes, a young man whose father had originated the idea of protecting property by electric wires in 1858. Holmes was the first practical man who dared to offer telephone service for sale. He had obtained two telephones, numbers six and seven, the first five having gone to the junk-heap; and he attached these to a wire in his burglar-alarm office. For two weeks his business friends played with the telephones, like boys with a fascinating toy; then Holmes nailed up a new shelf in his office, and on this shelf placed six box-telephones in a row. These could be switched into connection with the burglar-alarm wires and any two of the six wires could be joined by a wire cord. Nothing could have been simpler, but it was the arrival of a new idea in the business world. The Holmes exchange was on the top floor of a little building, and in almost every other city the first exchange was as near the roof as possible, partly to save rent and partly because most of the wires were strung on roof-tops. As the telephone itself had been born in a cellar, so the exchange was born in a garret. Usually, too, each exchange was an off-shoot of some other wire-using business. It was a medley of makeshifts. Almost every part of its outfit had been made for other uses. In Chicago all calls came in to one boy, who bawled them up a speaking-tube to the operators. In another city a boy received the calls, wrote them on white alleys, and rolled them to the boys at the switchboard. There was no number system. Every one was called by name. Even as late as 1880, when New York boasted fifteen hundred telephones, names were still in use. And as the first telephones were used both as transmitters and receivers, there was usually posted up a rule that was highly important: "Don't Talk with your Ear or Listen with your Mouth." To describe one of those early telephone exchanges in the silence of a printed page is a wholly impossible thing. Nothing but a language of noise could convey the proper impression. An editor who visited the Chicago exchange in 1879 said of it: "The racket is almost deafening. Boys are rushing madly hither and thither, while others are putting in or taking out pegs from a central framework as if they were lunatics engaged in a game of fox and geese." In the same year E. J. Hall wrote from Buffalo that his exchange with twelve boys had become "a perfect Bedlam." By the clumsy methods of those days, from two to six boys were needed to handle each call. And as there was usually more or less of a cat-and-dog squabble between the boys and the public, with every one yelling at the top of his voice, it may be imagined that a telephone exchange was a loud and frantic place. Boys, as operators, proved to be most complete and consistent failures. Their sins of omission and commission would fill a book. What with whittling the switchboards, swearing at subscribers, playing tricks with the wires, and roaring on all occasions like young bulls of Bashan, the boys in the first exchanges did their full share in adding to the troubles of the business. Nothing could be done with them. They were immune to all schemes of discipline. Like the MYSTERIOUS NOISES they could not be controlled, and by general consent they were abolished. In place of the noisy and obstreperous boy came the docile, soft-voiced girl. If ever the rush of women into the business world was an unmixed blessing, it was when the boys of the telephone exchanges were superseded by girls. Here at its best was shown the influence of the feminine touch. The quiet voice, pitched high, the deft fingers, the patient courtesy and attentiveness--these qualities were precisely what the gentle telephone required in its attendants. Girls were easier to train; they did not waste time in retaliatory conversation; they were more careful; and they were much more likely to give "the soft answer that turneth away wrath." A telephone call under the boy regime meant Bedlam and five minutes; afterwards, under the girl regime, it meant silence and twenty seconds. Instead of the incessant tangle and tumult, there came a new species of exchange--a quiet, tense place, in which several score of young ladies sit and answer the language of the switchboard lights. Now and then, not often, the signal lamps flash too quickly for these expert phonists. During the panic of 1907 there was one mad hour when almost every telephone in Wall Street region was being rung up by some desperate speculator. The switchboards were ablaze with lights. A few girls lost their heads. One fainted and was carried to the rest-room. But the others flung the flying shuttles of talk until, in a single exchange fifteen thousand conversations had been made possible in sixty minutes. There are always girls in reserve for such explosive occasions, and when the hands of any operator are seen to tremble, and she has a warning red spot on each cheek, she is taken off and given a recess until she recovers her poise. These telephone girls are the human part of a great communication machine. They are weaving a web of talk that changes into a new pattern every minute. How many possible combinations there are with the five million telephones of the Bell System, or what unthinkable mileage of conversation, no one has ever dared to guess. But whoever has once seen the long line of white arms waving back and forth in front of the switchboard lights must feel that he has looked upon the very pulse of the city's life. In 1902 the New York Telephone Company started a school, the first of its kind in the world, for the education of these telephone girls. This school is hidden amid ranges of skyscrapers, but seventeen thousand girls discover it in the course of the year. It is a most particular and exclusive school. It accepts fewer than two thousand of these girls, and rejects over fifteen thousand. Not more than one girl in every eight can measure up to its standards; and it cheerfully refuses as many students in a year as would make three Yales or Harvards. This school is unique, too, in the fact that it charges no fees, pays every student five dollars a week, and then provides her with a job when she graduates. But it demands that every girl shall be in good health, quick-handed, clear-voiced, and with a certain poise and alertness of manner. Presence of mind, which, in Herbert Spencer's opinion, ought to be taught in every university, is in various ways drilled into the temperament of the telephone girl. She is also taught the knack of concentration, so that she may carry the switchboard situation in her head, as a chess-player carries in his head the arrangement of the chess-men. And she is much more welcome at this strange school if she is young and has never worked in other trades, where less speed and vigilance are required. No matter how many millions of dollars may be spent upon cables and switchboards, the quality of telephone service depends upon the girl at the exchange end of the wire. It is she who meets the public at every point. She is the despatcher of all the talk trains; she is the ruler of the wire highways; and she is expected to give every passenger-voice an instantaneous express to its destination. More is demanded from her than from any other servant of the public. Her clients refuse to stand in line and quietly wait their turn, as they are quite willing to do in stores and theatres and barber shops and railway stations and everywhere else. They do not see her at work and they do not know what her work is. They do not notice that she answers a call in an average time of three and a half seconds. They are in a hurry, or they would not be at the telephone; and each second is a minute long. Any delay is a direct personal affront that makes a vivid impression upon their minds. And they are not apt to remember that most of the delays and blunders are being made, not by the expert girls, but by the careless people who persist in calling wrong numbers and in ignoring the niceties of telephone etiquette. The truth about the American telephone girl is that she has become so highly efficient that we now expect her to be a paragon of perfection. To give the young lady her due, we must acknowledge that she has done more than any other person to introduce courtesy into the business world. She has done most to abolish the old-time roughness and vulgarity. She has made big business to run more smoothly than little business did, half a century ago. She has shown us how to take the friction out of conversation, and taught us refinements of politeness which were rare even among the Beau Brummels of pre-telephonic days. Who, for instance, until the arrival of the telephone girl, appreciated the difference between "Who are you?" and "Who is this?" Or who else has so impressed upon us the value of the rising inflection, as a gentler habit of speech? This propaganda of politeness has gone so far that to-day the man who is profane or abusive at the telephone, is cut off from the use of it. He is cast out as unfit for a telephone-using community. And now, so that there shall be no anticlimax in this story of telephone development, we must turn the spot-light upon that immense aggregation of workshops in which have been made three-fifths of the telephone apparatus of the world--the Western Electric. The mother factory of this globe-trotting business is the biggest thing in the spacious back-yard of Chicago, and there are eleven smaller factories--her children--scattered over the earth from New York to Tokio. To put its totals into a sentence, it is an enterprise of 26,000-man-power, and 40,000,000-dollar-power; and the telephonic goods that it produces in half a day are worth one hundred thousand dollars--as much, by the way, as the Western Union REFUSED to pay for the Bell patents in 1877. The Western Electric was born in Chicago, in the ashes of the big fire of 1871; and it has grown up to its present greatness quietly, without celebrating its birthdays. At first it had no telephones to make. None had been invented, so it made telegraphic apparatus, burglar-alarms, electric pens, and other such things. But in 1878, when the Western Union made its short-lived attempt to compete with the Bell Company, the Western Electric agreed to make its telephones. Three years later, when the brief spasm of competition was ended, the Western Electric was taken in hand by the Bell people and has since then remained the great workshop of the telephone. The main plant in Chicago is not especially remarkable from a manufacturing point of view. Here are the inevitable lumber-yards and foundries and machine-shops. Here is the mad waltz of the spindles that whirl silk and cotton threads around the copper wires, very similar to what may be seen in any braid factory. Here electric lamps are made, five thousand of them in a day, in the same manner as elsewhere, except that here they are so small and dainty as to seem designed for fairy palaces. The things that are done with wire in the Western Electric factories are too many for any mere outsider to remember. Some wire is wrapped with paper tape at a speed of nine thousand miles a day. Some is fashioned into fantastic shapes that look like absurd sea-monsters, but which in reality are only the nerve systems of switchboards. And some is twisted into cables by means of a dozen whirling drums--a dizzying sight, as each pair of drums revolve in opposite directions. Because of the fact that a cable's inevitable enemy is moisture, each cable is wound on an immense spool and rolled into an oven until it is as dry as a cinder. Then it is put into a strait-jacket of lead pipe, sealed at both ends, and trundled into a waiting freight car. No other company uses so much wire and hard rubber, or so many tons of brass rods, as the Western Electric. Of platinum, too, which is more expensive than gold, it uses one thousand pounds a year in the making of telephone transmitters. This is imported from the Ural Mountains. The silk thread comes from Italy and Japan; the iron for magnets, from Norway; the paper tape, from Manila; the mahogany, from South America; and the rubber, from Brazil and the valley of the Congo. At least seven countries must cooperate to make a telephone message possible. Perhaps the most extraordinary feature in the Western Electric factories is the multitude of its inspectors. No other sort of manufacturing, not even a Government navy-yard, has so many. Nothing is too small to escape these sleuths of inspection. They test every tiny disc of mica, and throw away nine out of ten. They test every telephone by actual talk, set up every switchboard, and try out every cable. A single transmitter, by the time it is completed, has had to pass three hundred examinations; and a single coin-box is obliged to count ten thousand nickels before it graduates into the outer world. Seven hundred inspectors are on guard in the two main plants at Chicago and New York. This is a ruinously large number, from a profit-making point of view; but the inexorable fact is that in a telephone system nothing is insignificant. It is built on such altruistic lines that an injury to any one part is the concern of all. As usual, when we probe into the history of a business that has grown great and overspread the earth, we find a Man; and the Western Electric is no exception to this rule. Its Man, still fairly hale and busy after forty years of leadership, is Enos M. Barton. His career is the typical American story of self-help. He was a telegraph messenger boy in New York during the Civil War, then a telegraph operator in Cleveland. In 1869 his salary was cut down from one hundred dollars a month to ninety dollars; whereupon he walked out and founded the Western Electric in a shabby little machine-shop. Later he moved to Chicago, took in Elisha Gray as his partner, and built up a trade in the making of telegraphic materials. When the telephone was invented, Barton was one of the sceptics. "I well remember my disgust," he said, "when some one told me it was possible to send conversation along a wire." Several months later he saw a telephone and at once became one of its apostles. By 1882 his plant had become the official workshop of the Bell Companies. It was the headquarters of invention and manufacturing. Here was gathered a notable group of young men, brilliant and adventurous, who dared to stake their futures on the success of the telephone. And always at their head was Barton, as a sort of human switchboard, who linked them all together and kept them busy. In appearance, Enos M. Barton closely resembles ex-President Eliot, of Harvard. He is slow in speech, simple in manner, and with a rare sagacity in business affairs. He was not an organizer, in the modern sense. His policy was to pick out a man, put him in a responsible place, and judge him by results. Engineers could become bookkeepers, and bookkeepers could become engineers. Such a plan worked well in the earlier days, when the art of telephony was in the making, and when there was no source of authority on telephonic problems. Barton is the bishop emeritus of the Western Electric to-day; and the big industry is now being run by a group of young hustlers, with H. B. Thayer at the head of the table. Thayer is a Vermonter who has climbed the ladder of experience from its lower rungs to the top. He is a typical Yankee--lean, shrewd, tireless, and with a cold-blooded sense of justice that fits him for the leadership of twenty-six thousand people. So, as we have seen, the telephone as Bell invented it, was merely a brilliant beginning in the development of the art of telephony. It was an elfin birth--an elusive and delicate sprite that had to be nurtured into maturity. It was like a soul, for which a body had to be created; and no one knew how to make such a body. Had it been born in some less energetic country, it might have remained feeble and undeveloped; but not in the United States. Here in one year it had become famous, and in three years it had become rich. Bell's invincible patent was soon buttressed by hundreds of others. An open-door policy was adopted for invention. Change followed change to such a degree that the experts of 1880 would be lost to-day in the mazes of a telephone exchange. The art of the telephone engineer has in thirty years grown from the most crude and clumsy of experiments into an exact and comprehensive profession. As Carty has aptly said, "At first we invariably approached every problem from the wrong end. If we had been told to load a herd of cattle on a steamer, our method would have been to hire a Hagenbeck to train the cattle for a couple of years, so that they would know enough to walk aboard of the ship when he gave the signal; but to-day, if we had to ship cattle, we would know enough to make a greased chute and slide them on board in a jiffy." The telephone world has now its own standards and ideals. It has a language of its own, a telephonese that is quite unintelligible to outsiders. It has as many separate branches of study as medicine or law. There are few men, half a dozen at most, who can now be said to have a general knowledge of telephony. And no matter how wise a telephone expert may be, he can never reach perfection, because of the amazing variety of things that touch or concern his profession. "No one man knows all the details now," said Theodore Vail. "Several days ago I was walking through a telephone exchange and I saw something new. I asked Mr. Carty to explain it. He is our chief engineer; but he did not understand it. We called the manager. He did n't know, and called his assistant. He did n't know, and called the local engineer, who was able to tell us what it was." To sum up this development of the art of tele-phony--to present a bird's-eye view--it may be divided into four periods: 1. Experiment. 1876 to 1886. This was the period of invention, in which there were no experts and no authorities. Telephonic apparatus consisted of makeshifts and adaptations. It was the period of iron wire, imperfect transmitters, grounded circuits, boy operators, peg switchboards, local batteries, and overhead lines. 2. Development. 1886 to 1896. In this period amateurs became engineers. The proper type of apparatus was discovered, and was improved to a high point of efficiency. In this period came the multiple switchboard, copper wire, girl operators, underground cables, metallic circuit, common battery, and the long-distance lines. 3. Expansion. 1896 to 1906. This was the era of big business. It was an autumn period, in which the telephone men and the public began to reap the fruits of twenty years of investment and hard work. It was the period of the message rate, the pay station, the farm line, and the private branch exchange. 4. Organization. 1906--. With the success of the Pupin coil, there came a larger life for the telephone. It became less local and more national. It began to link together its scattered parts. It discouraged the waste and anarchy of duplication. It taught its older, but smaller brother, the telegraph, to cooperate. It put itself more closely in touch with the will of the public. And it is now pushing ahead, along the two roads of standardization and efficiency, toward its ideal of one universal telephone system for the whole nation. The key-word of the telephone development of to-day is this--organization. CHAPTER V. THE EXPANSION OF THE BUSINESS The telephone business did not really begin to grow big and overspread the earth until 1896, but the keynote of expansion was first sounded by Theodore Vail in the earliest days, when as yet the telephone was a babe in arms. In 1879 Vail said, in a letter written to one of his captains: "Tell our agents that we have a proposition on foot to connect the different cities for the purpose of personal communication, and in other ways to organize a GRAND TELEPHONIC SYSTEM." This was brave talk at that time, when there were not in the whole world as many telephones as there are to-day in Cincinnati. It was brave talk in those days of iron wire, peg switchboards, and noisy diaphragms. Most telephone men regarded it as nothing more than talk. They did not see any business future for the telephone except in short-distance service. But Vail was in earnest. His previous experience as the head of the railway mail service had lifted him up to a higher point of view. He knew the need of a national system of communication that would be quicker and more direct than either the telegraph or the post office. "I saw that if the telephone could talk one mile to-day," he said, "it would be talking a hundred miles to-morrow." And he persisted, in spite of a considerable deal of ridicule, in maintaining that the telephone was destined to connect cities and nations as well as individuals. Four months after he had prophesied the "grand telephonic system," he encouraged Charles J. Glidden, of world-tour fame, to build a telephone line between Boston and Lowell. This was the first inter-city line. It was well placed, as the owners of the Lowell mills lived in Boston, and it made a small profit from the start. This success cheered Vail on to a master-effort. He resolved to build a line from Boston to Providence, and was so stubbornly bent upon doing this that when the Bell Company refused to act, he picked up the risk and set off with it alone. He organized a company of well-known Rhode Islanders--nicknamed the "Governors' Company"--and built the line. It was a failure at first, and went by the name of "Vail's Folly." But Engineer Carty, by a happy thought, DOUBLED THE WIRE, and thus in a moment established two new factors in the telephone business--the Metallic Circuit and the Long Distance line. At once the Bell Company came over to Vail's point of view, bought his new line, and launched out upon what seemed to be the foolhardy enterprise of stringing a double wire from Boston to New York. This was to be not only the longest of all telephone lines, strung on ten thousand poles; it was to be a line de luxe, built of glistening red copper, not iron. Its cost was to be seventy thousand dollars, which was an enormous sum in those hardscrabble days. There was much opposition to such extravagance, and much ridicule. "I would n't take that line as a gift," said one of the Bell Company's officials. But when the last coil of wire was stretched into place, and the first "Hello" leaped from Boston to New York, the new line was a victorious success. It carried messages from the first day; and more, it raised the whole telephone business to a higher level. It swept away the prejudice that telephone service could become nothing more than a neighborhood affair. "It was the salvation of the business," said Edward J. Hill. It marked a turning-point in the history of the telephone, when the day of small things was ended and the day of great things was begun. No one man, no hundred men, had created it. It was the final result of ten years of invention and improvement. While this epoch-making line was being strung, Vail was pushing his "grand telephonic system" policy by organizing The American Telephone and Telegraph Company. This, too, was a master-stroke. It was the introduction of the staff-and-line method of organization into business. It was doing for the forty or fifty Bell Companies what Von Moltke did for the German army prior to the Franco-Prussian War. It was the creation of a central company that should link all local companies together, and itself own and operate the means by which these companies are united. This central company was to grapple with all national problems, to own all telephones and long-distance lines, to protect all patents, and to be the headquarters of invention, information, capital, and legal protection for the entire federation of Bell Companies. Seldom has a company been started with so small a capital and so vast a purpose. It had no more than $100,000 of capital stock, in 1885; but its declared object was nothing less than to establish a system of wire communication for the human race. Here are, in its own words, the marching orders of this Company: "To connect one or more points in each and every city, town, or place an the State of New York, with one or more points in each and every other city, town, or place in said State, and in each and every other of the United States, and in Canada, and Mexico; and each and every of said cities, towns, and places is to be connected with each and every other city, town, or place in said States and countries, and also by cable and other appropriate means with the rest of the known world." So ran Vail's dream, and for nine years he worked mightily to make it come true. He remained until the various parts of the business had grown together, and until his plan for a "grand telephonic system" was under way and fairly well understood. Then he went out, into a series of picturesque enterprises, until he had built up a four-square fortune; and recently, in 1907, he came back to be the head of the telephone business, and to complete the work of organization that he started thirty years before. When Vail said auf wiedersehen to the telephone business, it had passed from infancy to childhood. It was well shaped but not fully grown. Its pioneering days were over. It was self-supporting and had a little money in the bank. But it could not then have carried the load of traffic that it carries to-day. It had still too many problems to solve and too much general inertia to overcome. It needed to be conserved, drilled, educated, popularized. And the man who was finally chosen to replace Vail was in many respects the appropriate leader for such a preparatory period. Hudson--John Elbridge Hudson--was the name of the new head of the telephone people. He was a man of middle age, born in Lynn and bred in Boston; a long-pedigreed New Englander, whose ancestors had smelted iron ore in Lynn when Charles the First was King. He was a lawyer by profession and a university professor by temperament. His specialty, as a man of affairs, had been marine law; and his hobby was the collection of rare books and old English engravings. He was a master of the Greek language, and very fond of using it. On all possible occasions he used the language of Pericles in his conversation; and even carried this preference so far as to write his business memoranda in Greek. He was above all else a scholar, then a lawyer, and somewhat incidentally the central figure in the telephone world. But it was of tremendous value to the telephone business at that time to have at its head a man of Hudson's intellectual and moral calibre. He gave it tone and prestige. He built up its credit. He kept it clean and clear above all suspicion of wrong-doing. He held fast whatever had been gained. And he prepared the way for the period of expansion by borrowing fifty millions for improvements, and by adding greatly to the strength and influence of the American Telephone and Telegraph Company. Hudson remained at the head of the telephone table until his death, in 1900, and thus lived to see the dawn of the era of big business. Under his regime great things were done in the development of the art. The business was pushed ahead at every point by its captains. Every man in his place, trying to give a little better service than yesterday--that was the keynote of the Hudson period. There was no one preeminent genius. Each important step forward was the result of the cooperation of many minds, and the prodding necessities of a growing traffic. By 1896, when the Common Battery system created a new era, the telephone engineer had pretty well mastered his simpler troubles. He was able to handle his wires, no matter how many. By this time, too, the public was ready for the telephone. A new generation had grown up, without the prejudices of its fathers. People had grown away from the telegraphic habit of thought, which was that wire communications were expensive luxuries for the few. The telephone was, in fact, a new social nerve, so new and so novel that very nearly twenty years went by before it had fully grown into place, and before the social body developed the instinct of using it. Not that the difficulties of the telephone engineers were over, for they were not. They have seemed to grow more numerous and complex every year. But by 1896 enough had been done to warrant a forward movement. For the next ten-year period the keynote of telephone history was EXPANSION. Under the prevailing flat-rate plan of payment, all customers paid the same yearly price and then used their telephones as often as they pleased. This was a simple method, and the most satisfactory for small towns and farming regions. But in a great city such a plan grew to be suicidal. In New York, for instance, the price had to be raised to $240, which lifted the telephone as high above the mass of the citizens as though it were a piano or a diamond sunburst. Such a plan was strangling the business. It was shutting out the small users. It was clogging the wires with deadhead calls. It was giving some people too little service and others too much. It was a very unsatisfactory situation. How to extend the service and at the same time cheapen it to small users--that was the Gordian knot; and the man who unquestionably did most to untie it was Edward J. Hall. Mr. Hall founded the telephone business in Buffalo in 1878, and seven years afterwards became the chief of the long-distance traffic. He was then, and is to-day, one of the statesmen of the telephone. For more than thirty years he has been the "candid friend" of the business, incessantly suggesting, probing, and criticising. Keen and dispassionate, with a genius for mercilessly cutting to the marrow of a proposition, Hall has at the same time been a zealot for the improvement and extension of telephone service. It was he who set the agents free from the ball-and-chain of royalties, allowing them to pay instead a percentage of gross receipts. And it was he who "broke the jam," as a lumberman would say, by suggesting the MESSAGE RATE system. By this plan, which U. N. Bethell developed to its highest point in New York, a user of the telephone pays a fixed minimum price for a certain number of messages per year, and extra for all messages over this number. The large user pays more, and the little user pays less. It opened up the way to such an expansion of telephone business as Bell, in his rosiest dreams, had never imagined. In three years, after 1896, there were twice as many users; in six years there were four times as many; in ten years there were eight to one. What with the message rate and the pay station, the telephone was now on its way to be universal. It was adapted to all kinds and conditions of men. A great corporation, nerved at every point with telephone wires, may now pay fifty thousand dollars to the Bell Company, while at the same time a young Irish immigrant boy, just arrived in New York City, may offer five coppers and find at his disposal a fifty million dollar telephone system. When the message rate was fairly well established, Hudson died--fell suddenly to the ground as he was about to step into a railway carriage. In his place came Frederick P. Fish, also a lawyer and a Bostonian. Fish was a popular, optimistic man, with a "full-speed-ahead" temperament. He pushed the policy of expansion until he broke all the records. He borrowed money in stupendous amounts--$150,000,000 at one time--and flung it into a campaign of red-hot development. More business he demanded, and more, and more, until his captains, like a thirty-horse team of galloping horses, became very nearly uncontrollable. It was a fast and furious period. The whole country was ablaze with a passion of prosperity. After generations of conflict, the men with large ideas had at last put to rout the men of small ideas. The waste and folly of competition had everywhere driven men to the policy of cooperation. Mills were linked to mills and factories to factories, in a vast mutualism of industry such as no other age, perhaps, has ever known. And as the telephone is essentially the instrument of co-working and interdependent people, it found itself suddenly welcomed as the most popular and indispensable of all the agencies that put men in touch with each other. To describe this growth in a single sentence, we might say that the Bell telephone secured its first million of capital in 1879; its first million of earnings in 1882; its first million of dividends in 1884; its first million of surplus in 1885. It had paid out its first million for legal expenses by 1886; began first to send a million messages a day in 1888; had strung its first million miles of wire in 1900; and had installed its first million telephones in 1898. By 1897 it had spun as many cobwebs of wire as the mighty Western Union itself; by 1900 it had twice as many miles of wire as the Western Union, and in 1905 FIVE TIMES as many. Such was the plunging progress of the Bell Companies in this period of expansion, that by 1905 they had swept past all European countries combined, not only in the quality of the service but in the actual number of telephones in use. This, too, without a cent of public money, or the protection of a tariff, or the prestige of a governmental bureau. By 1892 Boston and New York were talking to Chicago, Milwaukee, Pittsburg, and Washington. One-half of the people of the United States were within talking distance of each other. The THOUSAND-MILE TALK had ceased to be a fairy tale. Several years later the western end of the line was pushed over the plains to Nebraska, enabling the spoken word in Boston to be heard in Omaha. Slowly and with much effort the public were taught to substitute the telephone for travel. A special long-distance salon was fitted up in New York City to entice people into the habit of talking to other cities. Cabs were sent for customers; and when one arrived, he was escorted over Oriental rugs to a gilded booth, draped with silken curtains. This was the famous "Room Nine." By such and many other allurements a larger idea of telephone service was given to the public mind; until in 1909 at least eighteen thousand New York-Chicago conversations were held, and the revenue from strictly long-distance messages was twenty-two thousand dollars a day. By 1906 even the Rocky Mountain Bell Company had grown to be a ten-million-dollar enterprise. It began at Salt Lake City with a hundred telephones, in 1880. Then it reached out to master an area of four hundred and thirteen thousand square miles--a great Lone Land of undeveloped resources. Its linemen groped through dense forests where their poles looked like toothpicks beside the towering pines and cedars. They girdled the mountains and basted the prairies with wire, until the lonely places were brought together and made sociable. They drove off the Indians, who wanted the bright wire for ear-rings and bracelets; and the bears, which mistook the humming of the wires for the buzzing of bees, and persisted in gnawing the poles down. With the most heroic optimism, this Rocky Mountain Company persevered until, in 1906, it had created a seventy-thousand-mile nerve-system for the far West. Chicago, in this year, had two hundred thou-sand telephones in use, in her two hundred square miles of area. The business had been built up by General Anson Stager, who was himself wealthy, and able to attract the support of such men as John Crerar, H. H. Porter, and Robert T. Lincoln. Since 1882 it has paid dividends, and in one glorious year its stock soared to four hundred dollars a share. The old-timers--the men who clambered over roof-tops in 1878 and tacked iron wires wherever they could without being chased off--are still for the most part in control of the Chicago company. But as might have been expected, it was New York City that was the record-breaker when the era of telephone expansion arrived. Here the flood of big business struck with the force of a tidal wave. The number of users leaped from 56,000 in 1900 up to 810,000 in 1908. In a single year of sweating and breathless activity, 65,000 new telephones were put on desks or hung on walls--an average of one new user for every two minutes of the business day. Literally tons, and hundreds of tons, of telephones were hauled in drays from the factory and put in place in New York's homes and offices. More and more were demanded, until to-day there are more telephones in New York than there are in the four countries, France, Belgium, Holland, and Switzerland combined. As a user of telephones New York has risen to be unapproachable. Mass together all the telephones of London, Glasgow, Liverpool, Manchester, Birmingham, Leeds, Sheffleld, Bristol, and Belfast, and there will even then be barely as many as are carrying the conversations of this one American city. In 1879 the New York telephone directory was a small card, showing two hundred and fifty-two names; but now it has grown to be an eight-hundred-page quarterly, with a circulation of half a million, and requiring twenty drays, forty horses, and four hundred men to do the work of distribution. There was one shabby little exchange thirty years ago; but now there are fifty-two exchanges, as the nerve-centres of a vast fifty-million-dollar system. Incredible as it may seem to foreigners, it is literally true that in a single building in New York, the Hudson Terminal, there are more telephones than in Odessa or Madrid, more than in the two kingdoms of Greece and Bulgaria combined. Merely to operate this system requires an army of more than five thousand girls. Merely to keep their records requires two hundred and thirty-five million sheets of paper a year. Merely to do the writing of these records wears away five hundred and sixty thousand lead pencils. And merely to give these girls a cup of tea or coffee at noon, compels the Bell Company to buy yearly six thousand pounds of tea, seventeen thousand pounds of coffee, forty-eight thousand cans of condensed milk, and one hundred and forty barrels of sugar. The myriad wires of this New York system are tingling with talk every minute of the day and night. They are most at rest between three and four o'clock in the morning, although even then there are usually ten calls a minute. Between five and six o'clock, two thousand New Yorkers are awake and at the telephone. Half an hour later there are twice as many. Between seven and eight twenty-five thousand people have called up twenty-five thousand other people, so that there are as many people talking by wire as there were in the whole city of New York in the Revolutionary period. Even this is only the dawn of the day's business. By half-past eight it is doubled; by nine it is trebled; by ten it is multiplied sixfold; and by eleven the roar has become an incredible babel of one hundred and eighty thousand conversations an hour, with fifty new voices clamoring at the exchanges every second. This is "the peak of the load." It is the topmost pinnacle of talk. It is the utmost degree of service that the telephone has been required to give in any city. And it is as much a world's wonder, to men and women of imagination, as the steel mills of Homestead or the turbine leviathans that curve across the Atlantic Ocean in four and a half days. As to the men who built it up: Charles F. Cutler died in 1907, but most of the others are still alive and busy. Union N. Bethell, now in Cutler's place at the head of the New York Company, has been the operating chief for eighteen years. He is a man of shrewdness and sympathy, with a rare sagacity in solving knotty problems, a president of the new type, who regards his work as a sort of obligation he owes to the public. And just as foreigners go to Pittsburg to see the steel business at its best; just as they go to Iowa and Kansas to see the New Farmer, so they make pilgrimages to Bethell's office to learn the profession of telephony. This unparalleled telephone system of New York grew up without having at any time the rivalry of competition. But in many other cities and especially in the Middle West, there sprang up in 1895 a medley of independent companies. The time of the original patents had expired, and the Bell Companies found themselves freed from the expense of litigation only to be snarled up in a tangle of duplication. In a few years there were six thousand of these little Robinson Crusoe companies. And by 1901 they had put in use more than a million telephones and were professing to have a capital of a hundred millions. Most of these companies were necessary and did much to expand the telephone business into new territory. They were in fact small mutual associations of a dozen or a hundred farmers, whose aim was to get telephone service at cost. But there were other companies, probably a thousand or more, which were organized by promoters who built their hopes on the fact that the Bell Companies were unpopular, and on the myth that they were fabulously rich. Instead of legitimately extending telephone lines into communities that had none, these promoters proceeded to inflict the messy snarl of an overlapping system upon whatever cities would give them permission to do so. In this way, masked as competition, the nuisance and waste of duplication began in most American cities. The telephone business was still so young, it was so little appreciated even by the telephone officials and engineers, that the public regarded a second or a third telephone system in one city as quite a possible and desirable innovation. "We have two ears," said one promoter; "why not therefore have two telephones?" This duplication went merrily on for years before it was generally discovered that the telephone is not an ear, but a nerve system; and that such an experiment as a duplicate nerve system has never been attempted by Nature, even in her most frivolous moods. Most people fancied that a telephone system was practically the same as a gas or electric light system, which can often be duplicated with the result of cheaper rates and better service. They did not for years discover that two telephone companies in one city means either half service or double cost, just as two fire departments or two post offices would. Some of these duplicate companies built up a complete plant, and gave good local service, while others proved to be mere stock bubbles. Most of them were over-capitalized, depending upon public sympathy to atone for deficiencies in equipment. One which had printed fifty million dollars of stock for sale was sold at auction in 1909 for four hundred thousand dollars. All told, there were twenty-three of these bubbles that burst in 1905, twenty-one in 1906, and twelve in 1907. So high has been the death-rate among these isolated companies that at a recent convention of telephone agents, the chairman's gavel was made of thirty-five pieces of wood, taken from thirty-five switchboards of thirty-five extinct companies. A study of twelve single-system cities and twenty-seven double-system cities shows that there are about eleven per cent more telephones under the double-system, and that where the second system is put in, every fifth user is obliged to pay for two telephones. The rates are alike, whether a city has one or two systems. Duplicating companies raised their rates in sixteen cities out of the twenty-seven, and reduced them in one city. Taking the United States as a whole, there are to-day fully two hundred and fifty thousand people who are paying for two telephones instead of one, an economic waste of at least ten million dollars a year. A fair-minded survey of the entire independent telephone movement would probably show that it was at first a stimulant, followed, as stimulants usually are, by a reaction. It was unquestionably for several years a spur to the Bell Companies. But it did not fulfil its promises of cheap rates, better service, and high dividends; it did little or nothing to improve telephonic apparatus, producing nothing new except the automatic switchboard--a brilliant invention, which is now in its experimental period. In the main, perhaps, it has been a reactionary and troublesome movement in the cities, and a progressive movement among the farmers. By 1907 it was a wave that had spent its force. It was no longer rolling along easily on the broad ocean of hope, but broken and turned aside by the rocks of actual conditions. One by one the telephone promoters learned the limitations of an isolated company, and asked to be included as members of the Bell family. In 1907 four hundred and fifty-eight thousand independent telephones were linked by wire to the nearest Bell Company; and in 1908 these were followed by three hundred and fifty thousand more. After this landslide to the policy of consolidation, there still remained a fairly large assortment of independent companies; but they had lost their dreams and their illusions. As might have been expected, the independent movement produced a number of competent local leaders, but none of national importance. The Bell Companies, on the other hand, were officered by men who had for a quarter of a century been surveying telephone problems from a national point of view. At their head, from 1907 onwards, was Theodore N. Vail, who had returned dramatically, at the precise moment when he was needed, to finish the work that he had begun in 1878. He had been absent for twenty years, developing water-power and building street-railways in South America. In the first act of the telephone drama, it was he who put the enterprise upon a business basis, and laid down the first principles of its policy. In the second and third acts he had no place; but when the curtain rose upon the fourth act, Vail was once more the central figure, standing white-haired among his captains, and pushing forward the completion of the "grand telephonic system" that he had dreamed of when the telephone was three years old. Thus it came about that the telephone business was created by Vail, conserved by Hudson, expanded by Fish, and is now in process of being consolidated by Vail. It is being knit together into a stupendous Bell System--a federation of self-governing companies, united by a central company that is the busiest of them all. It is no longer protected by any patent monopoly. Whoever is rich enough and rash enough may enter the field. But it has all the immeasurable advantages that come from long experience, immense bulk, the most highly skilled specialists, and an abundance of capital. "The Bell System is strong," says Vail, "because we are all tied up together; and the success of one is therefore the concern of all." The Bell System! Here we have the motif of American telephone development. Here is the most comprehensive idea that has entered any telephone engineer's brain. Already this Bell System has grown to be so vast, so nearly akin to a national nerve system, that there is nothing else to which we can compare it. It is so wide-spread that few are aware of its greatness. It is strung out over fifty thousand cities and communities. If it were all gathered together into one place, this Bell System, it would make a city of Telephonia as large as Baltimore. It would contain half of the telephone property of the world. Its actual wealth would be fully $760,000,000, and its revenue would be greater than the revenue of the city of New York. Part of the property of the city of Telephonia consists of ten million poles, as many as would make a fence from New York to California, or put a stockade around Texas. If the Telephonians wished to use these poles at home, they might drive them in as piles along their water-front, and have a twenty-five thousand-acre dock; or if their city were a hundred square miles in extent, they might set up a seven-ply wall around it with these poles. Wire, too! Eleven million miles of it! This city of Telephonia would be the capital of an empire of wire. Not all the men in New York State could shoulder this burden of wire and carry it. Throw all the people of Illinois in one end of the scale, and put on the other side the wire-wealth of Telephonia, and long before the last coil was in place, the Illinoisans would be in the air. What would this city do for a living? It would make two-thirds of the telephones, cables, and switchboards of all countries. Nearly one-quarter of its citizens would work in factories, while the others would be busy in six thousand exchanges, making it possible for the people of the United States to talk to one another at the rate of SEVEN THOUSAND MILLION CONVERSATIONS A YEAR. The pay-envelope army that moves to work every morning in Telephonia would be a host of one hundred and ten thousand men and girls, mostly girls,--as many girls as would fill Vassar College a hundred times and more, or double the population of Nevada. Put these men and girls in line, march them ten abreast, and six hours would pass before the last company would arrive at the reviewing stand. In single file this throng of Telephonians would make a living wall from New York to New Haven. Such is the extraordinary city of which Alexander Graham Bell was the only resident in 1875. It has been built up without the backing of any great bank or multi-millionaire. There have been no Vanderbilts in it, no Astors, Rockefellers, Rothschilds, Harrimans. There are even now only four men who own as many as ten thousand shares of the stock of the central company. This Bell System stands as the life-work of unprivileged men, who are for the most part still alive and busy. With very few and trivial exceptions, every part of it was made in the United States. No other industrial organism of equal size owes foreign countries so little. Alike in its origin, its development, and its highest point of efficiency and expansion, the telephone is as essentially American as the Declaration of Independence or the monument on Bunker Hill. CHAPTER VI. NOTABLE USERS OF THE TELEPHONE What we might call the telephonization of city life, for lack of a simpler word, has remarkably altered our manner of living from what it was in the days of Abraham Lincoln. It has enabled us to be more social and cooperative. It has literally abolished the isolation of separate families, and has made us members of one great family. It has become so truly an organ of the social body that by telephone we now enter into contracts, give evidence, try lawsuits, make speeches, propose marriage, confer degrees, appeal to voters, and do almost everything else that is a matter of speech. In stores and hotels this wire traffic has grown to an almost bewildering extent, as these are the places where many interests meet. The hundred largest hotels in New York City have twenty-one thousand telephones--nearly as many as the continent of Africa and more than the kingdom of Spain. In an average year they send six million messages. The Waldorf-Astoria alone tops all residential buildings with eleven hundred and twenty telephones and five hundred thousand calls a year; while merely the Christmas Eve orders that flash into Marshall Field's store, or John Wanamaker's, have risen as high as the three thousand mark. Whether the telephone does most to concentrate population, or to scatter it, is a question that has not yet been examined. It is certainly true that it has made the skyscraper possible, and thus helped to create an absolutely new type of city, such as was never imagined even in the fairy tales of ancient nations. The skyscraper is ten years younger than the telephone. It is now generally seen to be the ideal building for business offices. It is one of the few types of architecture that may fairly be called American. And its efficiency is largely, if not mainly, due to the fact that its inhabitants may run errands by telephone as well as by elevator. There seems to be no sort of activity which is not being made more convenient by the telephone. It is used to call the duck-shooters in Western Canada when a flock of birds has arrived; and to direct the movements of the Dragon in Wagner's grand opera "Siegfried." At the last Yale-Harvard football game, it conveyed almost instantaneous news to fifty thousand people in various parts of New England. At the Vanderbilt Cup Race its wires girdled the track and reported every gain or mishap of the racing autos. And at such expensive pageants as that of the Quebec Tercentenary in 1908, where four thousand actors came and went upon a ten-acre stage, every order was given by telephone. Public officials, even in the United States, have been slow to change from the old-fashioned and more dignified use of written documents and uniformed messengers; but in the last ten years there has been a sweeping revolution in this respect. Government by telephone! This is a new idea that has already arrived in the more efficient departments of the Federal service. And as for the present Congress, that body has gone so far as to plan for a special system of its own, in both Houses, so that all official announcements may be heard by wire. Garfield was the first among American Presidents to possess a telephone. An exhibition instrument was placed in his house, without cost, in 1878, while he was still a member of Congress. Neither Cleveland nor Harrison, for temperamental reasons, used the magic wire very often. Under their regime, there was one lonely idle telephone in the White House, used by the servants several times a week. But with McKinley came a new order of things. To him a telephone was more than a necessity. It was a pastime, an exhilarating sport. He was the one President who really revelled in the comforts of telephony. In 1895 he sat in his Canton home and heard the cheers of the Chicago Convention. Later he sat there and ran the first presidential telephone campaign; talked to his managers in thirty-eight States. Thus he came to regard the telephone with a higher degree of appreciation than any of his predecessors had done, and eulogized it on many public occasions. "It is bringing us all closer together," was his favorite phrase. To Roosevelt the telephone was mainly for emergencies. He used it to the full during the Chicago Convention of 1907 and the Peace Conference at Portsmouth. But with Taft the telephone became again the common avenue of conversation. He has introduced at least one new telephonic custom a long-distance talk with his family every evening, when he is away from home. Instead of the solitary telephone of Cleveland-Harrison days, the White House has now a branch exchange of its own--Main 6--with a sheaf of wires that branch out into every room as well as to the nearest central. Next to public officials, bankers were perhaps the last to accept the facilities of the telephone. They were slow to abandon the fallacy that no business can be done without a written record. James Stillman, of New York, was first among bankers to foresee the telephone era. As early as 1875, while Bell was teaching his infant telephone to talk, Stillman risked two thousand dollars in a scheme to establish a crude dial system of wire communication, which later grew into New York's first telephone exchange. At the present time, the banker who works closest to his telephone is probably George W. Perkins, of the J. P. Morgan group of bankers. "He is the only man," says Morgan, "who can raise twenty millions in twenty minutes." The Perkins plan of rapid transit telephony is to prepare a list of names, from ten to thirty, and to flash from one to another as fast as the operator can ring them up. Recently one of the other members of the Morgan bank proposed to enlarge its telephone equipment. "What will we gain by more wires?" asked the operator. "If we were to put in a six-hundred pair cable, Mr. Perkins would keep it busy." The most brilliant feat of the telephone in the financial world was done during the panic of 1907. At the height of the storm, on a Saturday evening, the New York bankers met in an almost desperate conference. They decided, as an emergency measure of self-protection, not to ship cash to Western banks. At midnight they telephoned this decision to the bankers of Chicago and St. Louis. These men, in turn, conferred by telephone, and on Sunday afternoon called up the bankers of neighboring States. And so the news went from 'phone to 'phone, until by Monday morning all bankers and chief depositors were aware of the situation, and prepared for the team-play that prevented any general disaster. As for stockbrokers of the Wall Street species, they transact practically all their business by telephone. In their stock exchange stand six hundred and forty one booths, each one the terminus of a private wire. A firm of brokers will count it an ordinary year's talking to send fifty thousand messages; and there is one firm which last year sent twice as many. Of all brokers, the one who finally accomplished most by telephony was unquestionably E. H. Harriman. In the mansion that he built at Arden, there were a hundred telephones, sixty of them linked to the long-distance lines. What the brush is to the artist, what the chisel is to the sculptor, the telephone was to Harriman. He built his fortune with it. It was in his library, his bathroom, his private car, his camp in the Oregon wilder-ness. No transaction was too large or too involved to be settled over its wires. He saved the credit of the Erie by telephone--lent it five million dollars as he lay at home on a sickbed. "He is a slave to the telephone," wrote a magazine writer. "Nonsense," replied Harriman, "it is a slave to me." The telephone arrived in time to prevent big corporations from being unwieldy and aristocratic. The foreman of a Pittsburg coal company may now stand in his subterranean office and talk to the president of the Steel Trust, who sits on the twenty-first floor of a New York skyscraper. The long-distance talks, especially, have grown to be indispensable to the corporations whose plants are scattered and geographically misplaced--to the mills of New England, for instance, that use the cotton of the South and sell so much of their product to the Middle West. To the companies that sell perishable commodities, an instantaneous conversation with a buyer in a distant city has often saved a carload or a cargo. Such caterers as the meat-packers, who were among the first to realize what Bell had made possible, have greatly accelerated the wheels of their business by inter-city conversations. For ten years or longer the Cudahys have talked every business morning between Omaha and Boston, via fifteen hundred and seventy miles of wire. In the refining of oil, the Standard Oil Company alone, at its New York office, sends two hundred and thirty thousand messages a year. In the making of steel, a chemical analysis is made of each caldron of molten pig-iron, when it starts on its way to be refined, and this analysis is sent by telephone to the steelmaker, so that he will know exactly how each potful is to be handled. In the floating of logs down rivers, instead of having relays of shouters to prevent the logs from jamming, there is now a wire along the bank, with a telephone linked on at every point of danger. In the rearing of skyscrapers, it is now usual to have a temporary wire strung vertically, so that the architect may stand on the ground and confer with a foreman who sits astride of a naked girder three hundred feet up in the air. And in the electric light business, the current is distributed wholly by telephoned orders. To give New York the seven million electric lights that have abolished night in that city requires twelve private exchanges and five hundred and twelve telephones. All the power that creates this artificial daylight is generated at a single station, and let flow to twenty-five storage centres. Minute by minute, its flow is guided by an expert, who sits at a telephone exchange as though he were a pilot at the wheel of an ocean liner. The first steamship line to take notice of the telephone was the Clyde, which had a wire from dock to office in 1877; and the first railway was the Pennsylvania, which two years later was persuaded by Professor Bell himself to give it a trial in Altoona. Since then, this railroad has become the chief beneficiary of the art of telephony. It has one hundred and seventy-five exchanges, four hundred operators, thirteen thousand telephones, and twenty thousand miles of wire--a more ample system than the city of New York had in 1896. To-day the telephone goes to sea in the passenger steamer and the warship. Its wires are waiting at the dock and the depot, so that a tourist may sit in his stateroom and talk with a friend in some distant office. It is one of the most incredible miracles of telephony that a passenger at New York, who is about to start for Chicago on a fast express, may telephone to Chicago from the drawing-room of a Pullman. He himself, on the swiftest of all trains, will not arrive in Chicago for eighteen hours; but the flying words can make the journey, and RETURN, while his train is waiting for the signal to start. In the operation of trains, the railroads have waited thirty years before they dared to trust the telephone, just as they waited fifteen years before they dared to trust the telegraph. In 1883 a few railways used the telephone in a small way, but in 1907, when a law was passed that made telegraphers highly expensive, there was a general swing to the telephone. Several dozen roads have now put it in use, some employing it as an associate of the Morse method and others as a complete substitute. It has already been found to be the quickest way of despatching trains. It will do in five minutes what the telegraph did in ten. And it has enabled railroads to hire more suitable men for the smaller offices. In news-gathering, too, much more than in railroading, the day of the telephone has arrived. The Boston Globe was the first paper to receive news by telephone. Later came The Washington Star, which had a wire strung to the Capitol, and thereby gained an hour over its competitors. To-day the evening papers receive most of their news over the wire a la Bell instead of a la Morse. This has resulted in a specialization of reporters--one man runs for the news and another man writes it. Some of the runners never come to the office. They receive their assignments by telephone, and their salaries by mail. There are even a few who are allowed to telephone their news directly to a swift linotype operator, who clicks it into type on his machine, without the scratch of a pencil. This, of course, is the ideal method of news-gathering, which is rarely possible. A paper of the first class, such as The New York World, has now an outfit of twenty trunk lines and eighty telephones. Its outgoing calls are two hundred thousand a year and its incoming calls three hundred thousand, which means that for every morning, evening, or Sunday edition, there has been an average of seven hundred and fifty messages. The ordinary newspaper in a small town cannot afford such a service, but recently the United Press has originated a cooperative method. It telephones the news over one wire to ten or twelve newspapers at one time. In ten minutes a thousand words can in this way be flung out to a dozen towns, as quickly as by telegraph and much cheaper. But it is in a dangerous crisis, when safety seems to hang upon a second, that the telephone is at its best. It is the instrument of emergencies, a sort of ubiquitous watchman. When the girl operator in the exchange hears a cry for help--"Quick! The hospital!" "The fire department!" "The police!" she seldom waits to hear the number. She knows it. She is trained to save half-seconds. And it is at such moments, if ever, that the users of a telephone can appreciate its insurance value. No doubt, if a King Richard III were worsted on a modern battlefield, his instinctive cry would be, "My Kingdom for a telephone!" When instant action is needed in the city of New York, a General Alarm can in five minutes be sent by the police wires over its whole vast area of three hundred square miles. When, recently, a gas main broke in Brooklyn, sixty girls were at once called to the centrals in that part of the city to warn the ten thousand families who had been placed in danger. When the ill-fated General Slocum caught fire, a mechanic in a factory on the water-front saw the blaze, and had the presence of mind to telephone the newspapers, the hospitals, and the police. When a small child is lost, or a convict has escaped from prison, or the forest is on fire, or some menace from the weather is at hand, the telephone bells clang out the news, just as the nerves jangle the bells of pain when the body is in danger. In one tragic case, the operator in Folsom, New Mexico, refused to quit her post until she had warned her people of a flood that had broken loose in the hills above the village. Because of her courage, nearly all were saved, though she herself was drowned at the switchboard. Her name--Mrs. S. J. Rooke--deserves to be remembered. If a disaster cannot be prevented, it is the telephone, usually, that brings first aid to the injured. After the destruction of San Francisco, Governor Guild, of Massachusetts, sent an appeal for the stricken city to the three hundred and fifty-four mayors of his State; and by the courtesy of the Bell Company, which carried the messages free, they were delivered to the last and furthermost mayors in less than five hours. After the destruction of Messina, an order for enough lumber to build ten thousand new houses was cabled to New York and telephoned to Western lumbermen. So quickly was this order filled that on the twelfth day after the arrival of the cablegram, the ships were on their way to Messina with the lumber. After the Kansas City flood of 1903, when the drenched city was without railways or street-cars or electric lights, it was the telephone that held the city together and brought help to the danger-spots. And after the Baltimore fire, the telephone exchange was the last force to quit and the first to recover. Its girls sat on their stools at the switchboard until the window-panes were broken by the heat. Then they pulled the covers over the board and walked out. Two hours later the building was in ashes. Three hours later another building was rented on the unburned rim of the city, and the wire chiefs were at work. In one day there was a system of wires for the use of the city officials. In two days these were linked to long-distance wires; and in eleven days a two-thousand-line switchboard was in full working trim. This feat still stands as the record in rebuilding. In the supreme emergency of war, the telephone is as indispensable, very nearly, as the cannon. This, at least, is the belief of the Japanese, who handled their armies by telephone when they drove back the Russians. Each body of Japanese troops moved forward like a silkworm, leaving behind it a glistening strand of red copper wire. At the decisive battle of Mukden, the silk-worm army, with a million legs, crept against the Russian hosts in a vast crescent, a hundred miles from end to end. By means of this glistening red wire, the various batteries and regiments were organized into fifteen divisions. Each group of three divisions was wired to a general, and the five generals were wired to the great Oyama himself, who sat ten miles back of the firing-line and sent his orders. Whenever a regiment lunged forward, one of the soldiers carried a telephone set. If they held their position, two other soldiers ran forward with a spool of wire. In this way and under fire of the Russian cannon, one hundred and fifty miles of wire were strung across the battlefield. As the Japanese said, it was this "flying telephone" that enabled Oyama to manipulate his forces as handily as though he were playing a game of chess. It was in this war, too, that the Mikado's soldiers strung the costliest of all telephone lines, at 203 Metre Hill. When the wire had been basted up this hill to the summit, the fortress of Port Arthur lay at their mercy. But the climb had cost them twenty-four thousand lives. Of the seven million telephones in the United States, about two million are now in farmhouses. Every fourth American farmer is in telephone touch with his neighbors and the market. Iowa leads, among the farming States. In Iowa, not to have a telephone is to belong to what a Londoner would call the "submerged tenth" of the population. Second in line comes Illinois, with Kansas, Nebraska, and Indiana following closely behind; and at the foot of the list, in the matter of farm telephones, are Connecticut and Louisiana. The first farmer who discovered the value of the telephone was the market gardener. Next came the bonanza farmer of the Red River Valley--such a man, for instance, as Oliver Dalrymple, of North Dakota, who found that by the aid of the telephone he could plant and harvest thirty thousand acres of wheat in a single season. Then, not more than half a dozen years ago, there arose a veritable Telephone Crusade among the farmers of the Middle West. Cheap telephones, yet fairly good, had by this time been made possible by the improvements of the Bell engineers; and stories of what could be done by telephone became the favorite gossip of the day. One farmer had kept his barn from being burned down by telephoning for his neighbors; another had cleared five hundred dollars extra profit on the sale of his cattle, by telephoning to the best market; a third had rescued a flock of sheep by sending quick news of an approaching blizzard; a fourth had saved his son's life by getting an instantaneous message to the doctor; and so on. How the telephone saved a three million dollar fruit crop in Colorado, in 1909, is the story that is oftenest told in the West. Until that year, the frosts in the Spring nipped the buds. No farmer could be sure of his harvest. But in 1909, the fruit-growers bought smudge-pots--three hundred thousand or more. These were placed in the orchards, ready to be lit at a moment's notice. Next, an alliance was made with the United States Weather Bureau so that whenever the Frost King came down from the north, a warning could be telephoned to the farmers. Just when Colorado was pink with apple blossoms, the first warning came. "Get ready to light up your smudge-pots in half an hour." Then the farmers telephoned to the nearest towns: "Frost is coming; come and help us in the orchards." Hundreds of men rushed out into the country on horseback and in wagons. In half an hour the last warning came: "Light up; the thermometer registers twenty-nine." The smudge-pot artillery was set ablaze, and kept blazing until the news came that the icy forces had retreated. And in this way every Colorado farmer who had a telephone saved his fruit. In some farming States, the enthusiasm for the telephone is running so high that mass meetings are held, with lavish oratory on the general theme of "Good Roads and Telephones." And as a result of this Telephone Crusade, there are now nearly twenty thousand groups of farmers, each one with a mutual telephone system, and one-half of them with sufficient enterprise to link their little webs of wires to the vast Bell system, so that at least a million farmers have been brought as close to the great cities as they are to their own barns. What telephones have done to bring in the present era of big crops, is an interesting story in itself. To compress it into a sentence, we might say that the telephone has completed the labor-saving movement which started with the McCormick reaper in 1831. It has lifted the farmer above the wastefulness of being his own errand-boy. The average length of haul from barn to market in the United States is nine and a half miles, so that every trip saved means an extra day's work for a man and team. Instead of travelling back and forth, often to no purpose, the farmer may now stay at home and attend to his stock and his crops. As yet, few farmers have learned to appreciate the value of quality in telephone service, as they have in other lines. The same man who will pay six prices for the best seed-corn, and who will allow nothing but high-grade cattle in his barn, will at the same time be content with the shabbiest and flimsiest telephone service, without offering any other excuse than that it is cheap. But this is a transient phase of farm telephony. The cost of an efficient farm system is now so little--not more than two dollars a month, that the present trashy lines are certain sooner or later to go to the junk-heap with the sickle and the flail and all the other cheap and unprofitable things. CHAPTER VII. THE TELEPHONE AND NATIONAL EFFICIENCY The larger significance of the telephone is that it completes the work of eliminating the hermit and gypsy elements of civilization. In an almost ideal way, it has made intercommunication possible without travel. It has enabled a man to settle permanently in one place, and yet keep in personal touch with his fellows. Until the last few centuries, much of the world was probably what Morocco is to-day--a region without wheeled vehicles or even roads of any sort. There is a mythical story of a wonderful speaking-trumpet possessed by Alexander the Great, by which he could call a soldier who was ten miles distant; but there was probably no substitute for the human voice except flags and beacon-fires, or any faster method of travel than the gait of a horse or a camel across ungraded plains. The first sensation of rapid transit doubtless came with the sailing vessel; but it was the play-toy of the winds, and unreliable. When Columbus dared to set out on his famous voyage, he was five weeks in crossing from Spain to the West Indies, his best day's record two hundred miles. The swift steamship travel of to-day did not begin until 1838, when the Great Western raced over the Atlantic in fifteen days. As for organized systems of intercommunication, they were unknown even under the rule of a Pericles or a Caesar. There was no post office in Great Britain until 1656--a generation after America had begun to be colonized. There was no English mail-coach until 1784; and when Benjamin Franklin was Postmaster General at Philadelphia, an answer by mail from Boston, when all went well, required not less than three weeks. There was not even a hard-surface road in the thirteen United States until 1794; nor even a postage stamp until 1847, the year in which Alexander Graham Bell was born. In this same year Henry Clay delivered his memorable speech on the Mexican War, at Lexington, Kentucky, and it was telegraphed to The New York Herald at a cost of five hundred dollars, thus breaking all previous records for news-gathering enterprise. Eleven years later the first cable established an instantaneous sign-language between Americans and Europeans; and in 1876 there came the perfect distance-talking of the telephone. No invention has been more timely than the telephone. It arrived at the exact period when it was needed for the organization of great cities and the unification of nations. The new ideas and energies of science, commerce, and cooperation were beginning to win victories in all parts of the earth. The first railroad had just arrived in China; the first parliament in Japan; the first constitution in Spain. Stanley was moving like a tiny point of light through the heart of the Dark Continent. The Universal Postal Union had been organized in a little hall in Berne. The Red Cross movement was twelve years old. An International Congress of Hygiene was being held at Brussells, and an International Congress of Medicine at Philadelphia. De Lesseps had finished the Suez Canal and was examining Panama. Italy and Germany had recently been built into nations; France had finally swept aside the Empire and the Commune and established the Republic. And what with the new agencies of railroads, steamships, cheap newspapers, cables, and telegraphs, the civilized races of mankind had begun to be knit together into a practical consolidation. To the United States, especially, the telephone came as a friend in need. After a hundred years of growth, the Republic was still a loose confederation of separate States, rather than one great united nation. It had recently fallen apart for four years, with a wide gulf of blood between; and with two flags, two Presidents, and two armies. In 1876 it was hesitating halfway between doubt and confidence, between the old political issues of North and South, and the new industrial issues of foreign trade and the development of material resources. The West was being thrown open. The Indians and buffaloes were being driven back. There was a line of railway from ocean to ocean. The population was gaining at the rate of a million a year. Colorado had just been baptized as a new State. And it was still an unsolved problem whether or not the United States could be kept united, whether or not it could be built into an organic nation without losing the spirit of self-help and democracy. It is not easy for us to realize to-day how young and primitive was the United States of 1876. Yet the fact is that we have twice the population that we had when the telephone was invented. We have twice the wheat crop and twice as much money in circulation. We have three times the railways, banks, libraries, newspapers, exports, farm values, and national wealth. We have ten million farmers who make four times as much money as seven million farmers made in 1876. We spend four times as much on our public schools, and we put four times as much in the savings bank. We have five times as many students in the colleges. And we have so revolutionized our methods of production that we now produce seven times as much coal, fourteen times as much oil and pig-iron, twenty-two times as much copper, and forty-three times as much steel. There were no skyscrapers in 1876, no trolleys, no electric lights, no gasoline engines, no self-binders, no bicycles, no automobiles. There was no Oklahoma, and the combined population of Montana, Wyoming, Idaho, and Arizona was about equal to that of Des Moines. It was in this year that General Custer was killed by the Sioux; that the flimsy iron railway bridge fell at Ashtabula; that the "Molly Maguires" terrorized Pennsylvania; that the first wire of the Brooklyn Bridge was strung; and that Boss Tweed and Hell Gate were both put out of the way in New York. The Great Elm, under which the Revolutionary patriots had met, was still standing on Boston Common. Daniel Drew, the New York financier, who was born before the American Constitution was adopted, was still alive; so were Commodore Vanderbilt, Joseph Henry, A. T. Stewart, Thurlow Weed, Peter Cooper, Cyrus McCormick, Lucretia Mott, Bryant, Longfellow, and Emerson. Most old people could remember the running of the first railway train; people of middle age could remember the sending of the first telegraph message; and the children in the high schools remembered the laying of the first Atlantic Cable. The grandfathers of 1876 were fond of telling how Webster opposed taking Texas and Oregon into the Union; how George Washington advised against including the Mississippi River; and how Monroe warned Congress that a country that reached from the Atlantic to the Middle West was "too extensive to be governed but by a despotic monarchy." They told how Abraham Lincoln, when he was postmaster of New Salem, used to carry the letters in his coon-skin cap and deliver them at sight; how in 1822 the mails were carried on horseback and not in stages, so as to have the quickest possible service; and how the news of Madison's election was three weeks in reaching the people of Kentucky. When the telegraph was mentioned, they told how in Revolutionary days the patriots used a system of signalling called "Washington's Tele-graph," consisting of a pole, a flag, a basket, and a barrel. So, the young Republic was still within hearing distance of its childhood, in 1876. Both in sentiment and in methods of work it was living close to the log-cabin period. Many of the old slow ways survived, the ways that were fast enough in the days of the stage-coach and the tinder-box. There were seventy-seven thousand miles of railway, but poorly built and in short lengths. There were manufacturing industries that employed two million, four hundred thousand people, but every trade was broken up into a chaos of small competitive units, each at war with all the others. There were energy and enterprise in the highest degree, but not efficiency or organization. Little as we knew it, in 1876 we were mainly gathering together the plans and the raw materials for the building up of the modern business world, with its quick, tense life and its national structure of immense coordinated industries. In 1876 the age of specialization and community of interest was in its dawn. The cobbler had given place to the elaborate factory, in which seventy men cooperated to make one shoe. The merchant who had hitherto lived over his store now ventured to have a home in the suburbs. No man was any longer a self-sufficient Robinson Crusoe. He was a fraction, a single part of a social mechanism, who must necessarily keep in the closest touch with many others. A new interdependent form of civilization was about to be developed, and the telephone arrived in the nick of time to make this new civilization workable and convenient. It was the unfolding of a new organ. Just as the eye had become the telescope, and the hand had become machinery, and the feet had become railways, so the voice became the telephone. It was a new ideal method of communication that had been made indispensable by new conditions. The prophecy of Carlyle had come true, when he said that "men cannot now be bound to men by brass collars; you will have to bind them by other far nobler and cunninger methods." Railways and steamships had begun this work of binding man to man by "nobler and cunninger methods." The telegraph and cable had gone still farther and put all civilized people within sight of each other, so that they could communicate by a sort of deaf and dumb alphabet. And then came the telephone, giving direct instantaneous communication and putting the people of each nation within hearing distance of each other. It was the completion of a long series of inventions. It was the keystone of the arch. It was the one last improvement that enabled interdependent nations to handle themselves and to hold together. To make railways and steamboats carry letters was much, in the evolution of the means of communication. To make the electric wire carry signals was more, because of the instantaneous transmission of important news. But to make the electric wire carry speech was MOST, because it put all fellow-citizens face to face, and made both message and answer instantaneous. The invention of the telephone taught the Genie of Electricity to do better than to carry mes-sages in the sign language of the dumb. It taught him to speak. As Emerson has finely said: "We had letters to send. Couriers could not go fast enough, nor far enough; broke their wagons, foundered their horses; bad roads in Spring, snowdrifts in Winter, heat in Summer--could not get their horses out of a walk. But we found that the air and the earth were full of electricity, and always going our way, just the way we wanted to send. WOULD HE TAKE A MESSAGE, Just as lief as not; had nothing else to do; would carry it in no time." As to the exact value of the telephone to the United States in dollars and cents, no one can tell. One statistician has given us a total of three million dollars a day as the amount saved by using telephones. This sum may be far too high, or too low. It can be no more than a guess. The only adequate way to arrive at the value of the telephone is to consider the nation as a whole, to take it all in all as a going concern, and to note that such a nation would be absolutely impossible without its telephone service. Some sort of a slower and lower grade republic we might have, with small industrial units, long hours of labor, lower wages, and clumsier ways. The money loss would be enormous, but more serious still would be the loss in the QUALITY OF THE NATIONAL LIFE. Inevitably, an untelephoned nation is less social, less unified, less progressive, and less efficient. It belongs to an inferior species. How to make a civilization that is organized and quick, instead of a barbarism that was chaotic and slow--that is the universal human problem, not wholly solved to-day. And how to develop a science of intercommunication, which commenced when the wild animals began to travel in herds and to protect themselves from their enemies by a language of danger-signals, and to democratize this science until the entire nation becomes self-conscious and able to act as one living being--that is the part of this universal problem which finally necessitated the invention of the telephone. With the use of the telephone has come a new habit of mind. The slow and sluggish mood has been sloughed off. The old to-morrow habit has been superseded by "Do It To-day"; and life has become more tense, alert, vivid. The brain has been relieved of the suspense of waiting for an answer, which is a psychological gain of great importance. It receives its reply at once and is set free to consider other matters. There is less burden upon the memory and the WHOLE MIND can be given to each new proposition. A new instinct of speed has been developed, much more fully in the United States than elsewhere. "No American goes slow," said Ian Maclaren, "if he has the chance of going fast; he does not stop to talk if he can talk walking; and he does not walk if he can ride." He is as pleased as a child with a new toy when some speed record is broken, when a pair of shoes is made in eleven minutes, when a man lays twelve hundred bricks in an hour, or when a ship crosses the Atlantic in four and a half days. Even seconds are now counted and split up into fractions. The average time, for instance, taken to reply to a telephone call by a New York operator, is now three and two-fifth seconds; and even this tiny atom of time is being strenuously worn down. As a witty Frenchman has said, one of our most lively regrets is that while we are at the telephone we cannot do business with our feet. We regard it as a victory over the hostility of nature when we do an hour's work in a minute or a minute's work in a second. Instead of saying, as the Spanish do, "Life is too short; what can one person do?" an American is more apt to say, "Life is too short; therefore I must do to-day's work to-day." To pack a lifetime with energy--that is the American plan, and so to economize that energy as to get the largest results. To get a question asked and answered in five minutes by means of an electric wire, instead of in two hours by the slow trudging of a messenger boy--that is the method that best suits our passion for instantaneous service. It is one of the few social laws of which we are fairly sure, that a nation organizes in proportion to its velocity. We know that a four-mile-an-hour nation must remain a huge inert mass of peasants and villagers; or if, after centuries of slow toil, it should pile up a great city, the city will sooner or later fall to pieces of its own weight. In such a way Babylon rose and fell, and Nineveh, and Thebes, and Carthage, and Rome. Mere bulk, unorganized, becomes its own destroyer. It dies of clogging and congestion. But when Stephenson's Rocket ran twenty-nine miles an hour, and Morse's telegraph clicked its signals from Washington to Baltimore, and Bell's telephone flashed the vibrations of speech between Boston and Salem, a new era began. In came the era of speed and the finely organized nations. In came cities of unprecedented bulk, but held together so closely by a web-work of steel rails and copper wires that they have become more alert and cooperative than any tiny hamlet of mud huts on the banks of the Congo. That the telephone is now doing most of all, in this binding together of all manner of men, is perhaps not too much to claim, when we remember that there are now in the United States seventy thousand holders of Bell telephone stock and ten million users of telephone service. There are two hundred and sixty-four wires crossing the Mississippi, in the Bell system; and five hundred and forty-four crossing Mason and Dixon's Line. It is the telephone which does most to link together cottage and skyscraper and mansion and factory and farm. It is not limited to experts or college graduates. It reaches the man with a nickel as well as the man with a million. It speaks all languages and serves all trades. It helps to prevent sectionalism and race feuds. It gives a common meeting place to capitalists and wage-workers. It is so essentially the instrument of all the people, in fact, that we might almost point to it as a national emblem, as the trade-mark of democracy and the American spirit. In a country like ours, where there are eighty nationalities in the public schools, the telephone has a peculiar value as a part of the national digestive apparatus. It prevents the growth of dialects and helps on the process of assimilation. Such is the push of American life, that the humble immigrants from Southern Europe, before they have been here half a dozen years, have acquired the telephone habit and have linked on their small shops to the great wire network of intercommunication. In the one community of Brownsville, for example, settled several years ago by an overflow of Russian Jews from the East Side of New York, there are now as many telephones as in the kingdom of Greece. And in the swarming East Side itself, there is a single exchange in Orchard Street which has more wires than there are in all the exchanges of Egypt. There can be few higher ideals of practical democracy than that which comes to us from the telephone engineer. His purpose is much more comprehensive than the supplying of telephones to those who want them. It is rather to make the telephone as universal as the water faucet, to bring within speaking distance every economic unit, to connect to the social organism every person who may at any time be needed. Just as the click of the reaper means bread, and the purr of the sewing-machine means clothes, and the roar of the Bessemer converter means steel, and the rattle of the press means education, so the ring of the telephone bell has come to mean unity and organization. Already, by cable, telegraph, and telephone, no two towns in the civilized world are more than one hour apart. We have even girdled the earth with a cablegram in twelve minutes. We have made it possible for any man in New York City to enter into conversation with any other New Yorker in twenty-one seconds. We have not been satisfied with establishing such a system of transportation that we can start any day for anywhere from anywhere else; neither have we been satisfied with establishing such a system of communication that news and gossip are the common property of all nations. We have gone farther. We have established in every large region of population a system of voice-nerves that puts every man at every other man's ear, and which so magically eliminates the factor of distance that the United States becomes three thousand miles of neighbors, side by side. This effort to conquer Time and Space is above all else the instinct of material progress. To shrivel up the miles and to stretch out the minutes--this has been one of the master passions of the human race. And thus the larger truth about the telephone is that it is vastly more than a mere convenience. It is not to be classed with safety razors and piano players and fountain pens. It is nothing less than the high-speed tool of civilization, gearing up the whole mechanism to more effective social service. It is the symbol of national efficiency and cooperation. All this the telephone is doing, at a total cost to the nation of probably $200,000,000 a year--no more than American farmers earn in ten days. We pay the same price for it as we do for the potatoes, or for one-third of the hay crop, or for one-eighth of the corn. Out of every nickel spent for electrical service, one cent goes to the telephone. We could settle our telephone bill, and have several millions left over, if we cut off every fourth glass of liquor and smoke of tobacco. Whoever rents a typewriting machine, or uses a street car twice a day, or has his shoes polished once a day, may for the same expense have a very good telephone service. Merely to shovel away the snow of a single storm in 1910 cost the city government of New York as much as it will pay for five or six years of telephoning. This almost incredible cheapness of telephony is still far from being generally perceived, mainly for psychological reasons. A telephone is not impressive. It has no bulk. It is not like the Singer Building or the Lusitania. Its wires and switchboards and batteries are scattered and hidden, and few have sufficient imagination to picture them in all their complexity. If only it were possible to assemble the hundred or more telephone buildings of New York in one vast plaza, and if the two thousand clerks and three thousand maintenance men and six thousand girl operators were to march to work each morning with bands and banners, then, perhaps, there might be the necessary quality of impressiveness by which any large idea must always be imparted to the public mind. For lack of a seven and one-half cent coin, there is now five-cent telephony even in the largest American cities. For five cents whoever wishes has an entire wire-system at his service, a system that is kept waiting by day and night, so that it will be ready the instant he needs it. This system may have cost from twenty to fifty millions, yet it may be hired for one-eighth the cost of renting an automobile. Even in long-distance telephony, the expense of a message dwindles when it is compared with the price of a return railway ticket. A talk from New York to Philadelphia, for instance, costs seventy-five cents, while the railway fare would be four dollars. From New York to Chicago a talk costs five dollars as against seventy dollars by rail. As Harriman once said, "I can't get from my home to the depot for the price of a talk to Omaha." To say what the net profits have been, to the entire body of people who have invested money in the telephone, will always be more or less of a guess. The general belief that immense fortunes were made by the lucky holders of Bell stock, is an exaggeration that has been kept alive by the promoters of wildcat companies. No such fortunes were made. "I do not believe," says Theodore Vail, "that any one man ever made a clear million out of the telephone." There are not apt to be any get-rich-quick for-tunes made in corporations that issue no watered stock and do not capitalize their franchises. On the contrary, up to 1897, the holders of stock in the Bell Companies had paid in four million, seven hundred thousand dollars more than the par value; and in the recent consolidation of Eastern companies, under the presidency of Union N. Bethell, the new stock was actually eight millions less than the stock that was retired. Few telephone companies paid any profits at first. They had undervalued the cost of building and maintenance. Denver expected the cost to be two thousand, five hundred dollars and spent sixty thousand dollars. Buffalo expected to pay three thousand dollars and had to pay one hundred and fifty thousand dollars. Also, they made the unwelcome discovery that an exchange of two hundred costs more than twice as much as an exchange of one hundred, because of the greater amount of traffic. Usually a dollar that is paid to a telephone company is divided as follows: Rent............ 4c Taxes........... 4c Interest........ 6c Surplus......... 8c Maintenance.... 16c Dividends...... 18c Labor.......... 44c ---- $1.00 Most of the rate troubles (and their name has been legion) have arisen because the telephone business was not understood. In fact, until recently, it did not understand itself. It persisted in holding to a local and individualistic view of its business. It was slow to put telephones in unprofitable places. It expected every instrument to pay its way. In many States, both the telephone men and the public overlooked the most vital fact in the case, which is that the members of a telephone system are above all else INTERDEPENDENT. One telephone by itself has no value. It is as useless as a reed cut out of an organ or a finger that is severed from a hand. It is not even ornamental or adaptable to any other pur-pose. It is not at all like a piano or a talking-machine, which has a separate existence. It is useful only in proportion to the number of other telephones it reaches. AND EVERY TELEPHONE ANYWHERE ADDS VALUE TO EVERY OTHER TELEPHONE ON THE SAME SYSTEM OF WIRES. That, in a sentence, is the keynote of equitable rates. Many a telephone, for the general good, must be put where it does not earn its own living. At any time some sudden emergency may arise that will make it for the moment priceless. Especially since the advent of the automobile, there is no nook or corner from which it may not be supremely necessary, now and then, to send a message. This principle was acted upon recently in a most practical way by the Pennsylvania Railroad, which at its own expense installed five hundred and twenty-five telephones in the homes of its workmen in Altoona. In the same way, it is clearly the social duty of the telephone company to widen out its system until every point is covered, and then to distribute its gross charges as fairly as it can. The whole must carry the whole--that is the philosophy of rates which must finally be recognized by legislatures and telephone companies alike. It can never, of course, be reduced to a system or formula. It will always be a matter of opinion and compromise, requiring much skill and much patience. But there will seldom be any serious trouble when once its basic principles are understood. Like all time-saving inventions, like the railroad, the reaper, and the Bessemer converter, the telephone, in the last analysis, COSTS NOTHING; IT IS THE LACK OF IT THAT COSTS. THE NATION THAT MOST IS THE NATION WITHOUT IT. CHAPTER VIII. THE TELEPHONE IN FOREIGN COUNTRIES The telephone was nearly a year old before Europe was aware of its existence. It received no public notice of any kind whatever until March 3, 1877, when the London Athenaeum mentioned it in a few careful sentences. It was not welcomed, except by those who wished an evening's entertainment. And to the entire commercial world it was for four or five years a sort of scientific Billiken, that never could be of any service to serious people. One after another, several American enthusiasts rushed posthaste to Europe, with dreams of eager nations clamoring for telephone systems, and one after another they failed. Frederick A. Gower was the first of these. He was an adventurous chevalier of business who gave up an agent's contract in return for a right to become a roving propagandist. Later he met a prima donna, fell in love with and married her, forsook telephony for ballooning, and lost his life in attempting to fly across the English Channel. Next went William H. Reynolds, of Providence, who had bought five-eights of the British patent for five thousand dollars, and half the right to Russia, Spain, Portugal, and Italy for two thousand, five hundred dollars. How he was received may be seen from a letter of his which has been preserved. "I have been working in London for four months," he writes; "I have been to the Bank of England and elsewhere; and I have not found one man who will put one shilling into the telephone." Bell himself hurried to England and Scotland on his wedding tour in 1878, with great expectations of having his invention appreciated in his native land. But from a business point of view, his mission was a total failure. He received dinners a-plenty, but no contracts; and came back to the United States an impoverished and disheartened man. Then the optimistic Gardiner G. Hubbard, Bell's father-in-law, threw himself against the European inertia and organized the International and Oriental Telephone Companies, which came to nothing of any importance. In the same year even Enos M. Barton, the sagacious founder of the Western Electric, went to France and England to establish an export trade in telephones, and failed. These able men found their plans thwarted by the indifference of the public, and often by open hostility. "The telephone is little better than a toy," said the Saturday Review; "it amazes ignorant people for a moment, but it is inferior to the well-established system of air-tubes." "What will become of the privacy of life?" asked another London editor. "What will become of the sanctity of the domestic hearth?" Writers vied with each other in inventing methods of pooh-poohing Bell and his invention. "It is ridiculously simple," said one. "It is only an electrical speaking-tube," said another. "It is a complicated form of speaking-trumpet," said a third. No British editor could at first conceive of any use for the telephone, except for divers and coal miners. The price, too, created a general outcry. Floods of toy telephones were being sold on the streets at a shilling apiece; and although the Government was charging sixty dollars a year for the use of its printing-telegraphs, people protested loudly against paying half as much for telephones. As late as 1882, Herbert Spencer writes: "The telephone is scarcely used at all in London, and is unknown in the other English cities." The first man of consequence to befriend the telephone was Lord Kelvin, then an untitled young scientist. He had seen the original telephones at the Centennial in Philadelphia, and was so fascinated with them that the impulsive Bell had thrust them into his hands as a gift. At the next meeting of the British Association for the Advancement of Science, Lord Kelvin exhibited these. He did more. He became the champion of the telephone. He staked his reputation upon it. He told the story of the tests made at the Centennial, and assured the sceptical scientists that he had not been deceived. "All this my own ears heard," he said, "spoken to me with unmistakable distinctness by this circular disc of iron." The scientists and electrical experts were, for the most part, split up into two camps. Some of them said the telephone was impossible, while others said that "nothing could be simpler." Almost all were agreed that what Bell had done was a humorous trifle. But Lord Kelvin persisted. He hammered the truth home that the telephone was "one of the most interesting inventions that has ever been made in the history of science." He gave a demonstration with one end of the wire in a coal mine. He stood side by side with Bell at a public meeting in Glasgow, and declared: "The things that were called telephones before Bell were as different from Bell's telephone as a series of hand-claps are different from the human voice. They were in fact electrical claps; while Bell conceived the idea--THE WHOLLY ORIGINAL AND NOVEL IDEA--of giving continuity to the shocks, so as to perfectly reproduce the human voice." One by one the scientists were forced to take the telephone seriously. At a public test there was one noted professor who still stood in the ranks of the doubters. He was asked to send a message. He went to the instrument with a grin of incredulity, and thinking the whole exhibition a joke, shouted into the mouthpiece: "Hi diddle diddle--follow up that." Then he listened for an answer. The look on his face changed to one of the utmost amazement. "It says--`The cat and the fiddle,'" he gasped, and forthwith he became a convert to telephony. By such tests the men of science were won over, and by the middle of 1877 Bell received a "vociferous welcome" when he addressed them at their annual convention at Plymouth. Soon afterwards, The London Times surrendered. It whirled right-about-face and praised the telephone to the skies. "Suddenly and quietly the whole human race is brought within speaking and hearing distance," it exclaimed; "scarcely anything was more desired and more impossible." The next paper to quit the mob of scoffers was the Tatler, which said in an editorial peroration, "We cannot but feel im-pressed by the picture of a human child commanding the subtlest and strongest force in Nature to carry, like a slave, some whisper around the world." Closely after the scientists and editors came the nobility. The Earl of Caithness led the way. He declared in public that "the telephone is the most extraordinary thing I ever saw in my life." And one wintry morning in 1878 Queen Victoria drove to the house of Sir Thomas Biddulph, in London, and for an hour talked and listened by telephone to Kate Field, who sat in a Downing Street office. Miss Field sang "Kathleen Mavourneen," and the Queen thanked her by telephone, saying she was "immensely pleased." She congratulated Bell himself, who was present, and asked if she might be permitted to buy the two telephones; whereupon Bell presented her with a pair done in ivory. This incident, as may be imagined, did much to establish the reputation of telephony in Great Britain. A wire was at once strung to Windsor Castle. Others were ordered by the Daily News, the Persian Ambassador, and five or six lords and baronets. Then came an order which raised the hopes of the telephone men to the highest heaven, from the banking house of J. S. Morgan & Co. It was the first recognition from the "seats of the mighty" in the business and financial world. A tiny exchange, with ten wires, was promptly started in London; and on April 2d, 1879, Theodore Vail, the young manager of the Bell Company, sent an order to the factory in Boston, "Please make one hundred hand telephones for export trade as early as possible." The foreign trade had begun. Then there came a thunderbolt out of a blue sky, a wholly unforeseen disaster. Just as a few energetic companies were sprouting up, the Postmaster General suddenly proclaimed that the telephone was a species of telegraph. According to a British law the telegraph was required to be a Government monopoly. This law had been passed six years before the telephone was born, but no matter. The telephone men protested and argued. Tyndall and Lord Kelvin warned the Government that it was making an indefensible mistake. But nothing could be done. Just as the first railways had been called toll-roads, so the telephone was solemnly declared to be a telegraph. Also, to add to the absurd humor of the situation, Judge Stephen, of the High Court of Justice, spoke the final word that compelled the telephone legally to be a telegraph, and sustained his opinion by a quotation from Webster's Dictionary, which was published twenty years before the telephone was invented. Having captured this new rival, what next? The Postmaster General did not know. He had, of course, no experience in telephony, and neither had any of his officials in the telegraph department. There was no book and no college to instruct him. His telegraph was then, as it is to-day, a business failure. It was not earning its keep. Therefore he did not dare to shoulder the risk of constructing a second system of wires, and at last consented to give licenses to private companies. But the muddle continued. In order to compel competition, according to the academic theories of the day, licenses were given to thir-teen private companies. As might have been expected, the ablest company quickly swallowed the other twelve. If it had been let alone, this company might have given good service, but it was hobbled and fenced in by jealous regulations. It was compelled to pay one-tenth of its gross earnings to the Post Office. It was to hold itself ready to sell out at six months' notice. And as soon as it had strung a long-distance system of wires, the Postmaster General pounced down upon it and took it away. Then, in 1900, the Post Office tossed aside all obligations to the licensed company, and threw open the door to a free-for-all competition. It undertook to start a second system in London, and in two years discovered its blunder and proposed to cooperate. It granted licenses to five cities that demanded municipal ownership. These cities set out bravely, with loud beating of drums, plunged from one mishap to another, and finally quit. Even Glasgow, the premier city of municipal ownership, met its Waterloo in the telephone. It spent one million, eight hundred thousand dollars on a plant that was obsolete when it was new, ran it for a time at a loss, and then sold it to the Post Office in 1906 for one million, five hundred and twenty-five thousand dollars. So, from first to last, the story of the telephone in Great Britain has been a "comedy of errors." There are now, in the two islands, not six hundred thousand telephones in use. London, with its six hundred and forty square miles of houses, has one-quarter of these, and is gaining at the rate of ten thousand a year. No large improvements are under way, as the Post Office has given notice that it will take over and operate all private companies on New Year's Day, 1912. The bureaucratic muddle, so it seems, is to continue indefinitely. In Germany there has been the same burden of bureaucracy, but less backing and filling. There is a complete government monopoly. Whoever commits the crime of leasing telephone service to his neighbors may be sent to jail for six months. Here, too, the Postmaster General has been supreme. He has forced the telephone business into a postal mould. The man in a small city must pay as high a rate for a small service, as the man in a large city pays for a large service. There is a fair degree of efficiency, but no high speed or record-breaking. The German engineers have not kept in close touch with the progress of telephony in the United States. They have preferred to devise methods of their own, and so have created a miscellaneous assortment of systems, good, bad, and indifferent. All told, there is probably an investment of seventy-five million dollars and a total of nine hundred thousand telephones. Telephony has always been in high favor with the Kaiser. It is his custom, when planning a hunting party, to have a special wire strung to the forest headquarters, so that he can converse every morning with his Cabinet. He has conferred degrees and honors by telephone. Even his former Chancellor, Von Buelow, received his title of Count in this informal way. But the first friend of the telephone in Germany was Bismarck. The old Unifier saw instantly its value in holding a nation together, and ordered a line between his palace in Berlin and his farm at Varzin, which lay two hundred and thirty miles apart. This was as early as the Fall of 1877, and was thus the first long-distance line in Europe. In France, as in England, the Government seized upon the telephone business as soon as the pioneer work had been done by private citizens. In 1889 it practically confiscated the Paris system, and after nine years of litigation paid five million francs to its owners. With this reckless beginning, it floundered from bad to worse. It assembled the most complete assortment of other nations' mistakes, and invented several of its own. Almost every known evil of bureaucracy was developed. The system of rates was turned upside down; the flat rate, which can be profitably permitted in small cities only, was put in force in the large cities, and the message rate, which is applicable only to large cities, was put in force in small places. The girl operators were entangled in a maze of civil service rules. They were not allowed to marry without the permission of the Postmaster General; and on no account might they dare to marry a mayor, a policeman, a cashier, or a foreigner, lest they betray the secrets of the switchboard. There was no national plan, no standardization, no staff of inventors and improvers. Every user was required to buy his own telephone. As George Ade has said, "Anything attached to a wall is liable to be a telephone in Paris." And so, what with poor equipment and red tape, the French system became what it remains to-day, the most conspicuous example of what NOT to do in telephony. There are barely as many telephones in the whole of France as ought normally to be in the city of Paris. There are not as many as are now in use in Chicago. The exasperated Parisians have protested. They have presented a petition with thirty-two thousand names. They have even organized a "Kickers' League"--the only body of its kind in any country--to demand good service at a fair price. The daily loss from bureaucratic telephony has become enormous. "One blundering girl in a telephone exchange cost me five thousand dollars on the day of the panic in 1907," said George Kessler. But the Government clears a net profit of three million dollars a year from its telephone monopoly; and until 1910, when a committee of betterment was appointed, it showed no concern at the discomfort of the public. There was one striking lesson in telephone efficiency which Paris received in 1908, when its main exchange was totally destroyed by fire. "To build a new switchboard," said European manufacturers, "will require four or five months." A hustling young Chicagoan appeared on the scene. "We 'll put in a new switchboard in sixty days," he said; "and agree to forfeit six hundred dollars a day for delay." Such quick work had never been known. But it was Chicago's chance to show what she could do. Paris and Chicago are four thousand, five hundred miles apart, a twelve days' journey. The switchboard was to be a hundred and eighty feet in length, with ten thousand wires. Yet the Western Electric finished it in three weeks. It was rushed on six freight-cars to New York, loaded on the French steamer La Provence, and deposited at Paris in thirty-six days; so that by the time the sixty days had expired, it was running full speed with a staff of ninety operators. Russia and Austria-Hungary have now about one hundred and twenty-five thousand telephones apiece. They are neck and neck in a race that has not at any time been a fast one. In each country the Government has been a neglectful stepmother to the telephone. It has starved the business with a lack of capital and used no enterprise in expanding it. Outside of Vienna, Budapest, St. Petersburg, and Moscow there are no wire-systems of any consequence. The political deadlock between Austria and Hungary shuts out any immediate hope of a happier life for the telephone in those countries; but in Russia there has recently been a change in policy that may open up a new era. Permits are now being offered to one private company in each city, in return for three per cent of the revenue. By this step Russia has unexpectedly swept to the front and is now, to telephone men, the freest country in Europe. In tiny Switzerland there has been government ownership from the first, but with less detriment to the business than elsewhere. Here the officials have actually jilted the telegraph for the telephone. They have seen the value of the talking wire to hold their valley villages together; and so have cries-crossed the Alps with a cheap and somewhat flimsy system of telephony that carries sixty million conversations a year. Even the monks of St. Bernard, who rescue snowbound travellers, have now equipped their mountain with a series of telephone booths. The highest telephone in the world is on the peak of Monte Rosa, in the Italian Alps, very nearly three miles above the level of the sea. It is linked to a line that runs to Rome, in order that a queen may talk to a professor. In this case the Queen is Margherita of Italy and the professor is Signor Mosso, the astronomer, who studies the heavens from an observatory on Monte Rosa. At her own expense, the Queen had this wire strung by a crew of linemen, who slipped and floundered on the mountain for six years before they had it pegged in place. The general situation in Italy is like that in Great Britain. The Government has always monopolized the long-distance lines, and is now about to buy out all private companies. There are only fifty-five thousand telephones to thirty-two million people--as many as in Norway and less than in Denmark. And in many of the southern and Sicilian provinces the jingle of the telephone bell is still an unfamiliar sound. The main peculiarity in Holland is that there is no national plan, but rather a patchwork, that resembles Joseph's coat of many colors. Each city engineer has designed his own type of apparatus and had it made to order. Also, each company is fenced in by law within a six-mile circle, so that Holland is dotted with thumb-nail systems, no two of which are alike. In Belgium there has been a government system since 1893, hence there is unity, but no enterprise. The plant is old-fashioned and too small. Spain has private companies, which give fairly good service to twenty thousand people. Roumania has half as many. Portugal has two small companies in Lisbon and Oporto. Greece, Servia, and Bulgaria have a scanty two thousand apiece. The frozen little isle of Iceland has one-quarter as many; and even into Turkey, which was a forbidden land under the regime of the old Sultan, the Young Turks are importing boxes of telephones and coils of copper wire. There is one European country, and only one, which has caught the telephone spirit--Sweden. Here telephony had a free swinging start. It was let alone by the Post Office; and better still, it had a Man, a business-builder of remarkable force and ability, named Henry Cedergren. Had this man been made the Telephone-Master of Europe, there would have been a different story to tell. By his insistent enterprise he made Stockholm the best telephoned city outside of the United States. He pushed his country forward until, having one hundred and sixty-five thousand telephones, it stood fourth among the European nations. Since his death the Government has entered the field with a duplicate system, and a war has been begun which grows yearly more costly and absurd. Asia, as yet, with her eight hundred and fifty million people, has fewer telephones than Philadelphia, and three-fourths of them are in the tiny island of Japan. The Japanese were enthusiastic telephonists from the first. They had a busy exchange in Tokio in 1883. This has now grown to have twenty-five thousand users, and might have more, if it had not been stunted by the peculiar policy of the Government. The public officials who operate the system are able men. They charge a fair price and make ten per cent profit for the State. But they do not keep pace with the demand. It is one of the oddest vagaries of public ownership that there is now in Tokio a WAITING LIST of eight thousand citizens, who are offering to pay for telephones and cannot get them. And when a Tokian dies, his franchise to a telephone, if he has one, is usually itemized in his will as a four-hundred-dollar property. India, which is second on the Asiatic list, has no more than nine thousand telephones--one to every thirty-three thousand of her population! Not quite so many, in fact, as there are in five of the skyscrapers of New York. The Dutch East Indies and China have only seven thousand apiece, but in China there has recently come a forward movement. A fund of twenty million dollars is to be spent in constructing a national system of telephone and telegraph. Peking is now pointing with wonder and delight to a new exchange, spick and span, with a couple of ten-thousand-wire switchboards. Others are being built in Canton, Hankow, and Tien-Tsin. Ultimately, the telephone will flourish in China, as it has done in the Chinese quarter in San Francisco. The Empress of China, after the siege of Peking, commanded that a telephone should be hung in her palace, within reach of her dragon throne; and she was very friendly with any representative of the "Speaking Lightning Sounds" business, as the Chinese term telephony. In Persia the telephone made its entry recently in true comic-opera fashion. A new Shah, in an outburst of confidence, set up a wire between his palace and the market-place in Teheran, and invited his people to talk to him whenever they had grievances. And they talked! They talked so freely and used such language, that the Shah ordered out his soldiers and attacked them. He fired upon the new Parliament, and was at once chased out of Persia by the enraged people. From this it would appear that the telephone ought to be popular in Persia, although at present there are not more than twenty in use. South America, outside of Buenos Ayres, has few telephones, probably not more than thirty thousand. Dom Pedro of Brazil, who befriended Bell at the Centennial, introduced telephony into his country in 1881; but it has not in thirty years been able to obtain ten thousand users. Canada has exactly the same number as Sweden--one hundred and sixty-five thousand. Mexico has perhaps ten thousand; New Zealand twenty-six thousand; and Australia fifty-five thousand. Far down in the list of continents stands Africa. Egypt and Algeria have twelve thousand at the north; British South Africa has as many at the south; and in the vast stretches between there are barely a thousand more. Whoever pushes into Central Africa will still hear the beat of the wooden drum, which is the clattering sign-language of the natives. One strand of copper wire there is, through the Congo region, placed there by order of the late King of Belgium. To string it was probably the most adventurous piece of work in the history of telephone linemen. There was one seven hundred and fifty mile stretch of the central jungle. There were white ants that ate the wooden poles, and wild elephants that pulled up the iron poles. There were monkeys that played tag on the lines, and savages that stole the wire for arrow-heads. But the line was carried through, and to-day is alive with conversations concerning rubber and ivory. So, we may almost say of the telephone that "there is no speech nor language where its voice is not heard." There are even a thousand miles of its wire in Abyssinia and one hundred and fifty miles in the Fiji Islands. Roughly speaking, there are now ten million telephones in all countries, employing two hundred and fifty thousand people, requiring twenty-one million miles of wire, representing a cost of fifteen hundred million dollars, and carrying fourteen thousand million conversations a year. All this, and yet the men who heard the first feeble cry of the infant telephone are still alive, and not by any means old. No foreign country has reached the high American level of telephony. The United States has eight telephones per hundred of population, while no other country has one-half as many. Canada stands second, with almost four per hundred; and Sweden is third. Germany has as many telephones as the State of New York; and Great Britain as many as Ohio. Chicago has more than London; and Boston twice as many as Paris. In the whole of Europe, with her twenty nations, there are one-third as many telephones as in the United States. In proportion to her population, Europe has only one-thirteenth as many. The United States writes half as many letters as Europe, sends one-third as many telegrams, and talks twice as much at the telephone. The average European family sends three telegrams a year, and three letters and one telephone message a week; while the average American family sends five telegrams a year, and seven letters and eleven telephone messages a week. This one na-tion, which owns six per cent of the earth and is five per cent of the human race, has SEVENTY per cent of the telephones. And fifty per cent, or one-half, of the telephony of the world, is now comprised in the Bell System of this country. There are only six nations in Europe that make a fair showing--the Germans, British, Swedish, Danes, Norwegians, and Swiss. The others have less than one telephone per hundred. Little Denmark has more than Austria. Little Finland has better service than France. The Belgian telephones have cost the most--two hundred and seventy-three dollars apiece; and the Finnish telephones the least--eighty-one dollars. But a telephone in Belgium earns three times as much as one in Norway. In general, the lesson in Europe is this, that the telephone is what a nation makes it. Its usefulness depends upon the sense and enterprise with which it is handled. It may be either an invaluable asset or a nuisance. Too much government! That has been the basic reason for failure in most countries. Before the telephone was invented, the telegraph had been made a State monopoly; and the tele-phone was regarded as a species of telegraph. The public officials did not see that a telephone system is a highly complex and technical problem, much more like a piano factory or a steel-mill. And so, wherever a group of citizens established a telephone service, the government officials looked upon it with jealous eyes, and usually snatched it away. The telephone thus became a part of the telegraph, which is a part of the post office, which is a part of the government. It is a fraction of a fraction of a fraction--a mere twig of bureaucracy. Under such conditions the telephone could not prosper. The wonder is that it survived. Handled on the American plan, the telephone abroad may be raised to American levels. There is no racial reason for failure. The slow service and the bungling are the natural results of treating the telephone as though it were a road or a fire department; and any nation that rises to a proper conception of the telephone, that dares to put it into competent hands and to strengthen it with enough capital, can secure as alert and brisk a service as heart can wish. Some nations are already on the way. China, Japan, and France have sent delegations to New York City--"the Mecca of telephone men," to learn the art of telephony in its highest development. Even Russia has rescued the telephone from her bureaucrats and is now offering it freely to men of enterprise. In most foreign countries telephone service is being steadily geared up to a faster pace. The craze for "cheap and nasty" telephony is passing; and the idea that the telephone is above all else a SPEED instrument, is gaining ground. A faster long-distance service, at double rates, is being well patronized. Slow-moving races are learning the value of time, which is the first lesson in telephony. Our reapers and mowers now go to seventy-five nations. Our street cars run in all great cities. Morocco is importing our dollar watches; Korea is learning the waste of allowing nine men to dig with one spade. And all this means telephones. In thirty years, the Western Electric has sold sixty-seven million dollars' worth of telephonic apparatus to foreign countries. But this is no more than a fair beginning. To put one telephone in China to every hundred people will mean an outlay of three hundred million dollars. To give Europe as fit an equipment as the United States now has, will mean thirty million telephones, with proper wire and switchboards to match. And while telephony for the masses is not yet a live question in many countries, sooner or later, in the relentless push of civilization, it must come. Possibly, in that far future of peace and goodwill among nations, when each country does for all the others what it can do best, the United States may be generally recognized as the source of skill and authority on telephony. It may be called in to rebuild or operate the telephone systems of other countries, in the same way that it is now supplying oil and steel rails and farm machinery. Just as the wise buyer of to-day asks France for champagne, Germany for toys, England for cottons, and the Orient for rugs, so he will learn to look upon the United States as the natural home and headquarters of the telephone. CHAPTER IX. THE FUTURE OF THE TELEPHONE In the Spring of 1907 Theodore N. Vail, a rugged, ruddy, white-haired man, was superintending the building of a big barn in northern Vermont. His house stood near-by, on a balcony of rolling land that overlooked the town of Lyndon and far beyond, across evergreen forests to the massive bulk of Burke Mountain. His farm, very nearly ten square miles in area, lay back of the house in a great oval of field and woodland, with several dozen cottages in the clearings. His Welsh ponies and Swiss cattle were grazing on the May grass, and the men were busy with the ploughs and harrows and seeders. It was almost thirty years since he had been called in to create the business structure of telephony, and to shape the general plan of its development. Since then he had done many other things. The one city of Buenos Ayres had paid him more, merely for giving it a system of trolleys and electric lights, than the United States had paid him for putting the telephone on a business basis. He was now rich and retired, free to enjoy his play-work of the farm and to forget the troubles of the city and the telephone. But, as he stood among his barn-builders, there arrived from Boston and New York a delegation of telephone directors. Most of them belonged to the "Old Guard" of telephony. They had fought under Vail in the pioneer days; and now they had come to ask him to return to the telephone business, after twenty years of absence. Vail laughed at the suggestion. "Nonsense," he said, "I'm too old. I'm sixty-two years of age." The directors persisted. They spoke of the approaching storm-cloud of panic and the need of another strong hand at the wheel until the crisis was over, but Vail still refused. They spoke of old times and old memories, but he shook his head. "All my life," he said, "I have wanted to be a farmer." Then they drew a picture of the telephone situation. They showed him that the "grand telephonic system" which he had planned was unfinished. He was its architect, and it was undone. The telephone business was energetic and prosperous. Under the brilliant leadership of Frederick P. Fish, it had grown by leaps and bounds. But it was still far from being the SYSTEM that Vail had dreamed of in his younger days; and so, when the directors put before him his unfinished plan, he surrendered. The instinct for completeness, which is one of the dominating characteristics of his mind, compelled him to consent. It was the call of the telephone. Since that May morning, 1907, great things have been done by the men of the telephone and telegraph world. The Bell System was brought through the panic without a scratch. When the doubt and confusion were at their worst, Vail wrote an open letter to his stock-holders, in his practical, farmer-like way. He said: "Our net earnings for the last ten months were $13,715,000, as against $11,579,000 for the same period in 1906. We have now in the banks over $18,000,000; and we will not need to borrow any money for two years." Soon afterwards, the work of consolidation began. Companies that overlapped were united. Small local wire-clusters, several thousands of them, were linked to the national lines. A policy of publicity superseded the secrecy which had naturally grown to be a habit in the days of patent litigation. Visitors and reporters found an open door. Educational advertisements were published in the most popular magazines. The corps of inventors was spurred up to conquer the long-distance problems. And in return for a thirty million check, the control of the historic Western Union was transferred from the children of Jay Gould to the thirty thousand stock-holders of the American Telephone and Telegraph Company. From what has been done, therefore, we may venture a guess as to the future of the telephone. This "grand telephonic system" which had no existence thirty years ago, except in the imagination of Vail, seems to be at hand. The very newsboys in the streets are crying it. And while there is, of course, no exact blueprint of a best possible telephone system, we can now see the general outlines of Vail's plan. There is nothing mysterious or ominous in this plan. It has nothing to do with the pools and conspiracies of Wall Street. No one will be squeezed out except the promoters of paper companies. The simple fact is that Vail is organizing a complete Bell System for the same reason that he built one big comfortable barn for his Swiss cattle and his Welsh ponies, instead of half a dozen small uncomfortable sheds. He has never been a "high financier" to juggle profits out of other men's losses. He is merely applying to the telephone business the same hard sense that any farmer uses in the management of his farm. He is building a Big Barn, metaphorically, for the telephone and telegraph. Plainly, the telephone system of the future will be national, so that any two people in the same country will be able to talk to one another. It will not be competitive, for the reason that no farmer would think for a moment of running his farm on competitive lines. It will have a staff-and-line organization, to use a military phrase. Each local company will continue to handle its own local affairs, and exercise to the full the basic virtue of self-help. But there will also be, as now, a central body of experts to handle the larger affairs that are common to all companies. No separateness or secession on the one side, nor bureaucracy on the other--that is the typically American idea that underlies the ideal telephone system. The line of authority, in such a system, will begin with the local manager. From him it will rise to the directors of the State company; then higher still to the directors of the national company; and finally, above all corporate leaders to the Federal Government itself. The failure of government ownership of the telephone in so many foreign countries does not mean that the private companies will have absolute power. Quite the reverse. The lesson of thirty years' experience shows that a private telephone company is apt to be much more obedient to the will of the people than if it were a Government department. But it is an axiom of democracy that no company, however well conducted, will be permitted to control a public convenience without being held strictly responsible for its own acts. As politics becomes less of a game and more of a responsibility, the telephone of the future will doubtless be supervised by some sort of public committee, which will have power to pass upon complaints, and to prevent the nuisance of duplication and the swindle of watering stock. As this Federal supervision becomes more and more efficient, the present fear of monopoly will decrease, just as it did in the case of the railways. It is a fact, although now generally forgotten, that the first railways of the United States were run for ten years or more on an anti-monopoly plan. The tracks were free to all. Any one who owned a cart with flanged wheels could drive it on the rails and compete with the locomotives. There was a happy-go-lucky jumble of trains and wagons, all held back by the slowest team; and this continued on some railways until as late as 1857. By that time the people saw that com-petition on a railway track was absurd. They allowed each track to be monopolized by one company, and the era of expansion began. No one, certainly, at the present time, regrets the passing of the independent teamster. He was much more arbitrary and expensive than any railroad has ever dared to be; and as the country grew, he became impossible. He was not the fittest to survive. For the general good, he was held back from competing with the railroad, and taught to cooperate with it by hauling freight to and from the depots. This, to his surprise, he found much more profitable and pleasant. He had been squeezed out of a bad job into a good one. And by a similar process of evolution, the United States is rapidly outgrowing the small independent telephone companies. These will eventually, one by one, rise as the teamster did to a higher social value, by clasping wires with the main system of telephony. Until 1881 the Bell System was in the hands of a family group. It was a strictly private enterprise. The public had been asked to help in its launching, and had refused. But after 1881 it passed into the control of the small stock-holders, and has remained there without a break. It is now one of our most democratized businesses, scattering either wages or dividends into more than a hundred thousand homes. It has at times been exclusive, but never sordid. It has never been dollar-mad, nor frenzied by the virus of stock-gambling. There has always been a vein of sentiment in it that kept it in touch with human nature. Even at the present time, each check of the American Telephone and Telegraph Company carries on it a picture of a pretty Cupid, sitting on a chair upon which he has placed a thick book, and gayly prattling into a telephone. Several sweeping changes may be expected in the near future, now that there is team-play between the Bell System and the Western Union. Already, by a stroke of the pen, five million users of telephones have been put on the credit books of the Western Union; and every Bell telephone office is now a telegraph office. Three telephone messages and eight telegrams may be sent AT THE SAME TIME over two pairs of wires: that is one of the recent miracles of science, and is now to be tried out upon a gigantic scale. Most of the long-distance telephone wires, fully two million miles, can be used for telegraphic purposes; and a third of the Western Union wires, five hundred thousand miles, may with a few changes be used for talking. The Western Union is paying rent for twenty-two thousand, five hundred offices, all of which helps to make telegraphy a luxury of the few. It is employing as large a force of messenger-boys as the army that marched with General Sherman from Atlanta to the sea. Both of these items of expense will dwindle when a Bell wire and a Morse wire can be brought to a common terminal; and when a telegram can be received or delivered by telephone. There will also be a gain, perhaps the largest of all, in removing the trudging little messenger-boy from the streets and sending him either to school or to learn some useful trade. The fact is that the United States is the first country that has succeeded in putting both telephone and telegraph upon the proper basis. Elsewhere either the two are widely apart, or the telephone is a mere adjunct of a telegraphic department. According to the new American plan, the two are not competitive, but complementary. The one is a supplement to the other. The post office sends a package; the telegraph sends the contents of the package; but the telephone sends nothing. It is an apparatus that makes conversation possible between two separated people. Each of the three has a distinct field of its own, so that there has never been any cause for jealousy among them. To make the telephone an annex of the post office or the telegraph has become absurd. There are now in the whole world very nearly as many messages sent by telephone as by letter; and there are THIRTY-TWO TIMES as many telephone calls as telegrams. In the United States, the telephone has grown to be the big brother of the telegraph. It has six times the net earnings and eight times the wire. And it transmits as many messages as the combined total of telegrams, letters, and railroad passengers. This universal trend toward consolidation has introduced a variety of problems that will engage the ablest brains in the telephone world for many years to come. How to get the benefits of organization without its losses, to become strong without losing quickness, to become systematic without losing the dash and dare of earlier days, to develop the working force into an army of high-speed specialists without losing the bird's-eye view of the whole situation,--these are the riddles of the new type, for which the telephonists of the next generation must find the answers. They illustrate the nature of the big jobs that the telephone has to offer to an ambitious and gifted young man of to-day. "The problems never were as large or as complex as they are right now," says J. J. Carty, the chief of the telephone engineers. The eternal struggle remains between the large and little ideas--between the men who see what might be and the men who only see what IS. There is still the race to break records. Already the girl at the switchboard can find the person wanted in thirty seconds. This is one-tenth of the time that was taken in the early centrals; but it is still too long. It is one-half of a valuable minute. It must be cut to twenty-five seconds, or twenty or fifteen. There is still the inventors' battle to gain miles. The distance over which conversations can be held has been increased from twenty miles to twenty-five hundred. But this is not far enough. There are some civilized human beings who are twelve thousand miles apart, and who have interests in common. During the Boxer Rebellion in China, for instance, there were Americans in Peking who would gladly have given half of their fortune for the use of a pair of wires to New York. In the earliest days of the telephone, Bell was fond of prophesying that "the time will come when we will talk across the Atlantic Ocean"; but this was regarded as a poetical fancy until Pupin invented his method of automatically propelling the electric current. Since then the most conservative engineer will discuss the problem of transatlantic telephony. And as for the poets, they are now dreaming of the time when a man may speak and hear his own voice come back to him around the world. The immediate long-distance problem is, of course, to talk from New York to the Pacific. The two oceans are now only three and a half days apart by rail. Seattle is clamoring for a wire to the East. San Diego wants one in time for her Panama Canal Exposition in 1915. The wires are already strung to San Francisco, but cannot be used in the present stage of the art. And Vail's captains are working now with almost breathless haste to give him a birthday present of a talk across the continent from his farm in Vermont. "I can see a universal system of telephony for the United States in the very near future," says Carty. "There is a statue of Seward standing in one of the streets of Seattle. The inscription upon it is, `To a United Country.' But as an Easterner stands there, he feels the isolation of that Far Western State, and he will always feel it, until he can talk from one side of the United States to the other. For my part," continues Carty, "I believe we will talk across continents and across oceans. Why not? Are there not more cells in one human body than there are people in the whole earth?" Some future Carty may solve the abandoned problem of the single wire, and cut the copper bill in two by restoring the grounded circuit. He may transmit vision as well as speech. He may perfect a third-rail system for use on moving trains. He may conceive of an ideal insulating material to supersede glass, mica, paper, and enamel. He may establish a universal code, so that all persons of importance in the United States shall have call-numbers by which they may instantly be located, as books are in a library. Some other young man may create a commercial department on wide lines, a work which telephone men have as yet been too specialized to do. Whoever does this will be a man of comprehensive brain. He will be as closely in touch with the average man as with the art of telephony. He will know the gossip of the street, the demands of the labor unions, and the policies of governors and presidents. The psychology of the Western farmer will concern him, and the tone of the daily press, and the methods of department stores. It will be his aim to know the subtle chemistry of public opinion, and to adapt the telephone service to the shifting moods and necessities of the times. HE WILL FIT TELEPHONY LIKE A GARMENT AROUND THE HABITS OF THE PEOPLE. Also, now that the telephone business has become strong, its next anxiety must be to develop the virtues, and not the defects, of strength. Its motto must be "Ich dien"--I serve; and it will be the work of the future statesmen of the telephone to illustrate this motto in all its practical variations. They will cater and explain, and explain and cater. They will educate and educate, until they have created an expert public. They will teach by pictures and lectures and exhibitions. They will have charts and diagrams hung in the telephone booths, so that the person who is waiting for a call may learn a little and pass the time more pleasantly. They will, in a word, attend to those innumerable trifles that make the perfection of public service. Already the Bell System has gone far in this direction by organizing what might fairly be called a foresight department. Here is where the fortune-tellers of the business sit. When new lines or exchanges are to be built, these men study the situation with an eye to the future. They prepare a "fundamental plan," outlining what may reasonably be expected to happen in fifteen or twenty years. Invariably they are optimists. They make provision for growth, but none at all for shrinkage. By their advice, there is now twenty-five million dollars' worth of reserve plant in the various Bell Companies, waiting for the country to grow up to it. Even in the city of New York, one-half of the cable ducts are empty, in expectation of the greater city of eight million population which is scheduled to arrive in 1928. There are perhaps few more impressive evidences of practical optimism and confidence than a new telephone exchange, with two-thirds of its wires waiting for the business of the future. Eventually, this foresight department will expand. It may, if a leader of genius appear, become the first real corps of practical sociologists, which will substitute facts for the present hotch-potch of theories. It will prepare a "fundamental plan" of the whole United States, showing the centre of each industry and the main runways of traffic. It will act upon the basic fact that WHEREVER THERE IS INTERDEPENDENCE, THERE IS BOUND TO BE TELEPHONY; and it will therefore prepare maps of interdependence, showing the widely scattered groups of industry and finance, and the lines that weave them into a pattern of national cooperation. As yet, no nation, not even our own, has seen the full value of the long-distance telephone. Few have the imagination to see what has been made possible, and to realize that an actual face-to-face conversation may take place, even though there be a thousand miles between. Neither can it seem credible that a man in a distant city may be located as readily as though he were close at hand. It is too amazing to be true, and possibly a new generation will have to arrive before it will be taken for granted and acted upon freely. Ultimately, there can be no doubt that long-distance telephony will be regarded as a national asset of the highest value, for the reason that it can prevent so much of the enormous economic waste of travel. Nothing that science can say will ever decrease the marvel of a long-distance conversation, and there may come in the future an Interpreter who will put it before our eyes in the form of a moving-picture. He will enable us to follow the flying words in a talk from Boston to Denver. We will flash first to Worcester, cross the Hudson on the high bridge at Poughkeepsie, swing southwest through a dozen coal towns to the outskirts of Philadelphia, leap across the Susquehanna, zigzag up and down the Alleghenies into the murk of Pittsburg, cross the Ohio at Wheeling, glance past Columbus and Indianapolis, over the Wabash at Terre Haute, into St. Louis by the Eads bridge, through Kansas City, across the Missouri, along the corn-fields of Kansas, and then on--on--on with the Sante Fe Railway, across vast plains and past the brink of the Grand Canyon, to Pueblo and the lofty city of Denver. Twenty-five hundred miles along a thousand tons of copper wire! From Bunker Hill to Pike's Peak IN A SECOND! Herbert Spencer, in his autobiography, alludes to the impressive fact that while the eye is reading a single line of type, the earth has travelled thirty miles through space. But this, in telephony, would be slow travelling. It is simple everyday truth to say that while your eye is reading this dash,--, a telephone sound can be carried from New York to Chicago. There are many reasons to believe that for the practical idealists of the future, the supreme study will be the force that makes such miracles possible. Six thousand million dollars--one-twentieth of our national wealth--is at the present time invested in electrical development. The Electrical Age has not yet arrived; but it is at hand; and no one can tell how brilliant the result may be, when the creative minds of a nation are focussed upon the subdual of this mysterious force, which has more power and more delicacy than any other force that man has been able to harness. As a tame and tractable energy, Electricity is new. It has no past and no pedigree. It is younger than many people who are now alive. Among the wise men of Greece and Rome, few knew its existence, and none put it to any practical use. The wisest knew that a piece of amber, when rubbed, will attract feathery substances. But they regarded this as poetry rather than science. There was a pretty legend among the Phoenicians that the pieces of amber were the petrified tears of maidens who had thrown themselves into the sea because of unrequited love, and each bead of amber was highly prized. It was worn as an amulet and a symbol of purity. Not for two thousand years did any one dream that within its golden heart lay hidden the secret of a new electrical civilization. Not even in 1752, when Benjamin Franklin flew his famous kite on the banks of the Schuylkill River, and captured the first CANNED LIGHTNING, was there any definite knowledge of electrical energy. His lightning-rod was regarded as an insult to the deity of Heaven. It was blamed for the earthquake of 1755. And not until the telegraph of Morse came into general use, did men dare to think of the thunder-bolt of Jove as a possible servant of the human race. Thus it happened that when Bell invented the telephone, he surprised the world with a new idea. He had to make the thought as well as the thing. No Jules Verne or H. G. Wells had foreseen it. The author of the Arabian Nights fantasies had conceived of a flying carpet, but neither he nor any one else had conceived of flying conversation. In all the literature of ancient days, there is not a line that will apply to the telephone, except possibly that expressive phrase in the Bible, "And there came a voice." In these more privileged days, the telephone has come to be regarded as a commonplace fact of everyday life; and we are apt to forget that the wonder of it has become greater and not less; and that there are still honor and profit, plenty of both, to be won by the inventor and the scientist. The flood of electrical patents was never higher than now. There are literally more in a single month than the total number issued by the Patent Office up to 1859. The Bell System has three hundred experts who are paid to do nothing else but try out all new ideas and inventions; and before these words can pass into the printed book, new uses and new methods will have been discovered. There is therefore no immediate danger that the art of telephony will be less fascinating in the future than it has been in the past. It will still be the most alluring and elusive sprite that ever led the way through a Dark Continent of mysterious phenomena. There still remains for some future scientist the task of showing us in detail exactly what the telephone current does. Such a man will study vibrations as Darwin studied the differentiation of species. He will investigate how a child's voice, speaking from Boston to Omaha, can vibrate more than a million pounds of copper wire; and he will invent a finer system of time to fit the telephone, which can do as many different things in a second as a man can do in a day, transmitting with every tick of the clock from twenty-five to eighty thousand vibrations. He will deal with the various vibrations of nerves and wires and wireless air, that are necessary in conveying thought between two separated minds. He will make clear how a thought, originating in the brain, passes along the nerve-wires to the vocal chords, and then in wireless vibration of air to the disc of the transmitter. At the other end of the line the second disc re-creates these vibrations, which impinge upon the nerve-wires of an ear, and are thus carried to the consciousness of another brain. And so, notwithstanding all that has been done since Bell opened up the way, the telephone remains the acme of electrical marvels. No other thing does so much with so little energy. No other thing is more enswathed in the unknown. Not even the gray-haired pioneers who have lived with the telephone since its birth, can understand their protege. As to the why and the how, there is as yet no answer. It is as true of telephony to-day as it was in 1876, that a child can use what the wisest sages cannot comprehend. Here is a tiny disc of sheet-iron. I speak--it shudders. It has a different shudder for every sound. It has thousands of millions of different shudders. There is a second disc many miles away, perhaps twenty-five hundred miles away. Between the two discs runs a copper wire. As I speak, a thrill of electricity flits along the wire. This thrill is moulded by the shudder of the disc. It makes the second disc shudder. And the shudder of the second disc reproduces my voice. That is what happens. But how--not all the scientists of the world can tell. The telephone current is a phenomenon of the ether, say the theorists. But what is ether? No one knows. Sir Oliver Lodge has guessed that it is "perhaps the only substantial thing in the material universe"; but no one knows. There is nothing to guide us in that unknown country except a sign-post that points upwards and bears the one word--"Perhaps." The ether of space! Here is an Eldorado for the scientists of the future, and whoever can first map it out will go far toward discovering the secret of telephony. Some day--who knows?--there may come the poetry and grand opera of the telephone. Artists may come who will portray the marvel of the wires that quiver with electrified words, and the romance of the switchboards that tremble with the secrets of a great city. Already Puvis de Chavannes, by one of his superb panels in the Boston Library, has admitted the telephone and the telegraph to the world of art. He has embodied them as two flying figures, poised above the electric wires, and with the following inscription underneath: "By the wondrous agency of electricity, speech dashes through space and swift as lightning bears tidings of good and evil." But these random guesses as to the future of the telephone may fall far short of what the reality will be. In these dazzling days it is idle to predict. The inventor has everywhere put the prophet out of business. Fact has outrun Fancy. When Morse, for instance, was tacking up his first little line of wire around the Speedwell Iron Works, who could have foreseen two hundred and fifty thousand miles of submarine cables, by which the very oceans are all aquiver with the news of the world? When Fulton's tiny tea-kettle of a boat steamed up the Hudson to Albany in two days, who could have foreseen the steel leviathans, one-sixth of a mile in length, that can in the same time cut the Atlantic Ocean in halves? And when Bell stood in a dingy workshop in Boston and heard the clang of a clock-spring come over an electric wire, who could have foreseen the massive structure of the Bell System, built up by half the telephones of the world, and by the investment of more actual capital than has gone to the making of any other industrial association? Who could have foreseen what the telephone bells have done to ring out the old ways and to ring in the new; to ring out delay, and isolation and to ring in the efficiency and the friendliness of a truly united people? 
101	----	THE HACKER CRACKDOWN Law and Disorder on the Electronic Frontier by Bruce Sterling CONTENTS Preface to the Electronic Release of The Hacker Crackdown Chronology of the Hacker Crackdown Introduction Part 1: CRASHING THE SYSTEM A Brief History of Telephony Bell's Golden Vaporware Universal Service Wild Boys and Wire Women The Electronic Communities The Ungentle Giant The Breakup In Defense of the System The Crash Post-Mortem Landslides in Cyberspace Part 2: THE DIGITAL UNDERGROUND Steal This Phone Phreaking and Hacking The View From Under the Floorboards Boards: Core of the Underground Phile Phun The Rake's Progress Strongholds of the Elite Sting Boards Hot Potatoes War on the Legion Terminus Phile 9-1-1 War Games Real Cyberpunk Part 3: LAW AND ORDER Crooked Boards The World's Biggest Hacker Bust Teach Them a Lesson The U.S. Secret Service The Secret Service Battles the Boodlers A Walk Downtown FCIC: The Cutting-Edge Mess Cyberspace Rangers FLETC: Training the Hacker-Trackers Part 4: THE CIVIL LIBERTARIANS NuPrometheus + FBI = Grateful Dead Whole Earth + Computer Revolution = WELL Phiber Runs Underground and Acid Spikes the Well The Trial of Knight Lightning Shadowhawk Plummets to Earth Kyrie in the Confessional $79,499 A Scholar Investigates Computers, Freedom, and Privacy Electronic Afterword to The Hacker Crackdown, Halloween 1993 THE HACKER CRACKDOWN Law and Disorder on the Electronic Frontier by Bruce Sterling Preface to the Electronic Release of The Hacker Crackdown January 1, 1994--Austin, Texas Hi, I'm Bruce Sterling, the author of this electronic book. Out in the traditional world of print, The Hacker Crackdown is ISBN 0-553-08058-X, and is formally catalogued by the Library of Congress as "1. Computer crimes--United States. 2. Telephone--United States--Corrupt practices. 3. Programming (Electronic computers)--United States--Corrupt practices." `Corrupt practices,' I always get a kick out of that description. Librarians are very ingenious people. The paperback is ISBN 0-553-56370-X. If you go and buy a print version of The Hacker Crackdown, an action I encourage heartily, you may notice that in the front of the book, beneath the copyright notice-- "Copyright (C) 1992 by Bruce Sterling"-- it has this little block of printed legal boilerplate from the publisher. It says, and I quote: "No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without permission in writing from the publisher. For information address: Bantam Books." This is a pretty good disclaimer, as such disclaimers go. I collect intellectual-property disclaimers, and I've seen dozens of them, and this one is at least pretty straightforward. In this narrow and particular case, however, it isn't quite accurate. Bantam Books puts that disclaimer on every book they publish, but Bantam Books does not, in fact, own the electronic rights to this book. I do, because of certain extensive contract maneuverings my agent and I went through before this book was written. I want to give those electronic publishing rights away through certain not-for-profit channels, and I've convinced Bantam that this is a good idea. Since Bantam has seen fit to peacably agree to this scheme of mine, Bantam Books is not going to fuss about this. Provided you don't try to sell the book, they are not going to bother you for what you do with the electronic copy of this book. If you want to check this out personally, you can ask them; they're at 1540 Broadway NY NY 10036. However, if you were so foolish as to print this book and start retailing it for money in violation of my copyright and the commercial interests of Bantam Books, then Bantam, a part of the gigantic Bertelsmann multinational publishing combine, would roust some of their heavy-duty attorneys out of hibernation and crush you like a bug. This is only to be expected. I didn't write this book so that you could make money out of it. If anybody is gonna make money out of this book, it's gonna be me and my publisher. My publisher deserves to make money out of this book. Not only did the folks at Bantam Books commission me to write the book, and pay me a hefty sum to do so, but they bravely printed, in text, an electronic document the reproduction of which was once alleged to be a federal felony. Bantam Books and their numerous attorneys were very brave and forthright about this book. Furthermore, my former editor at Bantam Books, Betsy Mitchell, genuinely cared about this project, and worked hard on it, and had a lot of wise things to say about the manuscript. Betsy deserves genuine credit for this book, credit that editors too rarely get. The critics were very kind to The Hacker Crackdown, and commercially the book has done well. On the other hand, I didn't write this book in order to squeeze every last nickel and dime out of the mitts of impoverished sixteen-year-old cyberpunk high-school-students. Teenagers don't have any money-- (no, not even enough for the six-dollar Hacker Crackdown paperback, with its attractive bright-red cover and useful index). That's a major reason why teenagers sometimes succumb to the temptation to do things they shouldn't, such as swiping my books out of libraries. Kids: this one is all yours, all right? Go give the print version back. *8-) Well-meaning, public-spirited civil libertarians don't have much money, either. And it seems almost criminal to snatch cash out of the hands of America's direly underpaid electronic law enforcement community. If you're a computer cop, a hacker, or an electronic civil liberties activist, you are the target audience for this book. I wrote this book because I wanted to help you, and help other people understand you and your unique, uhm, problems. I wrote this book to aid your activities, and to contribute to the public discussion of important political issues. In giving the text away in this fashion, I am directly contributing to the book's ultimate aim: to help civilize cyberspace. Information WANTS to be free. And the information inside this book longs for freedom with a peculiar intensity. I genuinely believe that the natural habitat of this book is inside an electronic network. That may not be the easiest direct method to generate revenue for the book's author, but that doesn't matter; this is where this book belongs by its nature. I've written other books--plenty of other books-- and I'll write more and I am writing more, but this one is special. I am making The Hacker Crackdown available electronically as widely as I can conveniently manage, and if you like the book, and think it is useful, then I urge you to do the same with it. You can copy this electronic book. Copy the heck out of it, be my guest, and give those copies to anybody who wants them. The nascent world of cyberspace is full of sysadmins, teachers, trainers, cybrarians, netgurus, and various species of cybernetic activist. If you're one of those people, I know about you, and I know the hassle you go through to try to help people learn about the electronic frontier. I hope that possessing this book in electronic form will lessen your troubles. Granted, this treatment of our electronic social spectrum is not the ultimate in academic rigor. And politically, it has something to offend and trouble almost everyone. But hey, I'm told it's readable, and at least the price is right. You can upload the book onto bulletin board systems, or Internet nodes, or electronic discussion groups. Go right ahead and do that, I am giving you express permission right now. Enjoy yourself. You can put the book on disks and give the disks away, as long as you don't take any money for it. But this book is not public domain. You can't copyright it in your own name. I own the copyright. Attempts to pirate this book and make money from selling it may involve you in a serious litigative snarl. Believe me, for the pittance you might wring out of such an action, it's really not worth it. This book don't "belong" to you. In an odd but very genuine way, I feel it doesn't "belong" to me, either. It's a book about the people of cyberspace, and distributing it in this way is the best way I know to actually make this information available, freely and easily, to all the people of cyberspace--including people far outside the borders of the United States, who otherwise may never have a chance to see any edition of the book, and who may perhaps learn something useful from this strange story of distant, obscure, but portentous events in so-called "American cyberspace." This electronic book is now literary freeware. It now belongs to the emergent realm of alternative information economics. You have no right to make this electronic book part of the conventional flow of commerce. Let it be part of the flow of knowledge: there's a difference. I've divided the book into four sections, so that it is less ungainly for upload and download; if there's a section of particular relevance to you and your colleagues, feel free to reproduce that one and skip the rest. [Project Gutenberg has reassembled the file, with Sterling's permission.] Just make more when you need them, and give them to whoever might want them. Now have fun. Bruce Sterling--bruces@well.sf.ca.us THE HACKER CRACKDOWN Law and Disorder on the Electronic Frontier by Bruce Sterling CHRONOLOGY OF THE HACKER CRACKDOWN 1865 U.S. Secret Service (USSS) founded. 1876 Alexander Graham Bell invents telephone. 1878 First teenage males flung off phone system by enraged authorities. 1939 "Futurian" science-fiction group raided by Secret Service. 1971 Yippie phone phreaks start YIPL/TAP magazine. 1972 RAMPARTS magazine seized in blue-box rip-off scandal. 1978 Ward Christenson and Randy Suess create first personal computer bulletin board system. 1982 William Gibson coins term "cyberspace." 1982 "414 Gang" raided. 1983-1983 AT&T dismantled in divestiture. 1984 Congress passes Comprehensive Crime Control Act giving USSS jurisdiction over credit card fraud and computer fraud. 1984 "Legion of Doom" formed. 1984. 2600: THE HACKER QUARTERLY founded. 1984. WHOLE EARTH SOFTWARE CATALOG published. 1985. First police "sting" bulletin board systems established. 1985. Whole Earth 'Lectronic Link computer conference (WELL) goes on-line. 1986 Computer Fraud and Abuse Act passed. 1986 Electronic Communications Privacy Act passed. 1987 Chicago prosecutors form Computer Fraud and Abuse Task Force. 1988 July. Secret Service covertly videotapes "SummerCon" hacker convention. September. "Prophet" cracks BellSouth AIMSX computer network and downloads E911 Document to his own computer and to Jolnet. September. AT&T Corporate Information Security informed of Prophet's action. October. Bellcore Security informed of Prophet's action. 1989 January. Prophet uploads E911 Document to Knight Lightning. February 25. Knight Lightning publishes E911 Document in PHRACK electronic newsletter. May. Chicago Task Force raids and arrests "Kyrie." June. "NuPrometheus League" distributes Apple Computer proprietary software. June 13. Florida probation office crossed with phone-sex line in switching-station stunt. July. "Fry Guy" raided by USSS and Chicago Computer Fraud and Abuse Task Force. July. Secret Service raids "Prophet," "Leftist," and "Urvile" in Georgia. 1990 January 15. Martin Luther King Day Crash strikes AT&T long-distance network nationwide. January 18-19. Chicago Task Force raids Knight Lightning in St. Louis. January 24. USSS and New York State Police raid "Phiber Optik," "Acid Phreak," and "Scorpion" in New York City. February 1. USSS raids "Terminus" in Maryland. February 3. Chicago Task Force raids Richard Andrews' home. February 6. Chicago Task Force raids Richard Andrews' business. February 6. USSS arrests Terminus, Prophet, Leftist, and Urvile. February 9. Chicago Task Force arrests Knight Lightning. February 20. AT&T Security shuts down public-access "attctc" computer in Dallas. February 21. Chicago Task Force raids Robert Izenberg in Austin. March 1. Chicago Task Force raids Steve Jackson Games, Inc., "Mentor," and "Erik Bloodaxe" in Austin. May 7,8,9. USSS and Arizona Organized Crime and Racketeering Bureau conduct "Operation Sundevil" raids in Cincinnatti, Detroit, Los Angeles, Miami, Newark, Phoenix, Pittsburgh, Richmond, Tucson, San Diego, San Jose, and San Francisco. May. FBI interviews John Perry Barlow re NuPrometheus case. June. Mitch Kapor and Barlow found Electronic Frontier Foundation; Barlow publishes CRIME AND PUZZLEMENT manifesto. July 24-27. Trial of Knight Lightning. 1991 February. CPSR Roundtable in Washington, D.C. March 25-28. Computers, Freedom and Privacy conference in San Francisco. May 1. Electronic Frontier Foundation, Steve Jackson, and others file suit against members of Chicago Task Force. July 1-2. Switching station phone software crash affects Washington, Los Angeles, Pittsburgh, San Francisco. September 17. AT&T phone crash affects New York City and three airports. Introduction This is a book about cops, and wild teenage whiz-kids, and lawyers, and hairy-eyed anarchists, and industrial technicians, and hippies, and high-tech millionaires, and game hobbyists, and computer security experts, and Secret Service agents, and grifters, and thieves. This book is about the electronic frontier of the 1990s. It concerns activities that take place inside computers and over telephone lines. A science fiction writer coined the useful term "cyberspace" in 1982, but the territory in question, the electronic frontier, is about a hundred and thirty years old. Cyberspace is the "place" where a telephone conversation appears to occur. Not inside your actual phone, the plastic device on your desk. Not inside the other person's phone, in some other city. THE PLACE BETWEEN the phones. The indefinite place OUT THERE, where the two of you, two human beings, actually meet and communicate. Although it is not exactly "real," "cyberspace" is a genuine place. Things happen there that have very genuine consequences. This "place" is not "real," but it is serious, it is earnest. Tens of thousands of people have dedicated their lives to it, to the public service of public communication by wire and electronics. People have worked on this "frontier" for generations now. Some people became rich and famous from their efforts there. Some just played in it, as hobbyists. Others soberly pondered it, and wrote about it, and regulated it, and negotiated over it in international forums, and sued one another about it, in gigantic, epic court battles that lasted for years. And almost since the beginning, some people have committed crimes in this place. But in the past twenty years, this electrical "space," which was once thin and dark and one-dimensional--little more than a narrow speaking-tube, stretching from phone to phone-- has flung itself open like a gigantic jack-in-the-box. Light has flooded upon it, the eerie light of the glowing computer screen. This dark electric netherworld has become a vast flowering electronic landscape. Since the 1960s, the world of the telephone has cross-bred itself with computers and television, and though there is still no substance to cyberspace, nothing you can handle, it has a strange kind of physicality now. It makes good sense today to talk of cyberspace as a place all its own. Because people live in it now. Not just a few people, not just a few technicians and eccentrics, but thousands of people, quite normal people. And not just for a little while, either, but for hours straight, over weeks, and months, and years. Cyberspace today is a "Net," a "Matrix," international in scope and growing swiftly and steadily. It's growing in size, and wealth, and political importance. People are making entire careers in modern cyberspace. Scientists and technicians, of course; they've been there for twenty years now. But increasingly, cyberspace is filling with journalists and doctors and lawyers and artists and clerks. Civil servants make their careers there now, "on-line" in vast government data-banks; and so do spies, industrial, political, and just plain snoops; and so do police, at least a few of them. And there are children living there now. People have met there and been married there. There are entire living communities in cyberspace today; chattering, gossiping, planning, conferring and scheming, leaving one another voice-mail and electronic mail, giving one another big weightless chunks of valuable data, both legitimate and illegitimate. They busily pass one another computer software and the occasional festering computer virus. We do not really understand how to live in cyberspace yet. We are feeling our way into it, blundering about. That is not surprising. Our lives in the physical world, the "real" world, are also far from perfect, despite a lot more practice. Human lives, real lives, are imperfect by their nature, and there are human beings in cyberspace. The way we live in cyberspace is a funhouse mirror of the way we live in the real world. We take both our advantages and our troubles with us. This book is about trouble in cyberspace. Specifically, this book is about certain strange events in the year 1990, an unprecedented and startling year for the the growing world of computerized communications. In 1990 there came a nationwide crackdown on illicit computer hackers, with arrests, criminal charges, one dramatic show-trial, several guilty pleas, and huge confiscations of data and equipment all over the USA. The Hacker Crackdown of 1990 was larger, better organized, more deliberate, and more resolute than any previous effort in the brave new world of computer crime. The U.S. Secret Service, private telephone security, and state and local law enforcement groups across the country all joined forces in a determined attempt to break the back of America's electronic underground. It was a fascinating effort, with very mixed results. The Hacker Crackdown had another unprecedented effect; it spurred the creation, within "the computer community," of the Electronic Frontier Foundation, a new and very odd interest group, fiercely dedicated to the establishment and preservation of electronic civil liberties. The crackdown, remarkable in itself, has created a melee of debate over electronic crime, punishment, freedom of the press, and issues of search and seizure. Politics has entered cyberspace. Where people go, politics follow. This is the story of the people of cyberspace. PART ONE: Crashing the System On January 15, 1990, AT&T's long-distance telephone switching system crashed. This was a strange, dire, huge event. Sixty thousand people lost their telephone service completely. During the nine long hours of frantic effort that it took to restore service, some seventy million telephone calls went uncompleted. Losses of service, known as "outages" in the telco trade, are a known and accepted hazard of the telephone business. Hurricanes hit, and phone cables get snapped by the thousands. Earthquakes wrench through buried fiber-optic lines. Switching stations catch fire and burn to the ground. These things do happen. There are contingency plans for them, and decades of experience in dealing with them. But the Crash of January 15 was unprecedented. It was unbelievably huge, and it occurred for no apparent physical reason. The crash started on a Monday afternoon in a single switching-station in Manhattan. But, unlike any merely physical damage, it spread and spread. Station after station across America collapsed in a chain reaction, until fully half of AT&T's network had gone haywire and the remaining half was hard-put to handle the overflow. Within nine hours, AT&T software engineers more or less understood what had caused the crash. Replicating the problem exactly, poring over software line by line, took them a couple of weeks. But because it was hard to understand technically, the full truth of the matter and its implications were not widely and thoroughly aired and explained. The root cause of the crash remained obscure, surrounded by rumor and fear. The crash was a grave corporate embarrassment. The "culprit" was a bug in AT&T's own software--not the sort of admission the telecommunications giant wanted to make, especially in the face of increasing competition. Still, the truth WAS told, in the baffling technical terms necessary to explain it. Somehow the explanation failed to persuade American law enforcement officials and even telephone corporate security personnel. These people were not technical experts or software wizards, and they had their own suspicions about the cause of this disaster. The police and telco security had important sources of information denied to mere software engineers. They had informants in the computer underground and years of experience in dealing with high-tech rascality that seemed to grow ever more sophisticated. For years they had been expecting a direct and savage attack against the American national telephone system. And with the Crash of January 15--the first month of a new, high-tech decade--their predictions, fears, and suspicions seemed at last to have entered the real world. A world where the telephone system had not merely crashed, but, quite likely, BEEN crashed--by "hackers." The crash created a large dark cloud of suspicion that would color certain people's assumptions and actions for months. The fact that it took place in the realm of software was suspicious on its face. The fact that it occurred on Martin Luther King Day, still the most politically touchy of American holidays, made it more suspicious yet. The Crash of January 15 gave the Hacker Crackdown its sense of edge and its sweaty urgency. It made people, powerful people in positions of public authority, willing to believe the worst. And, most fatally, it helped to give investigators a willingness to take extreme measures and the determination to preserve almost total secrecy. An obscure software fault in an aging switching system in New York was to lead to a chain reaction of legal and constitutional trouble all across the country. # Like the crash in the telephone system, this chain reaction was ready and waiting to happen. During the 1980s, the American legal system was extensively patched to deal with the novel issues of computer crime. There was, for instance, the Electronic Communications Privacy Act of 1986 (eloquently described as "a stinking mess" by a prominent law enforcement official). And there was the draconian Computer Fraud and Abuse Act of 1986, passed unanimously by the United States Senate, which later would reveal a large number of flaws. Extensive, well-meant efforts had been made to keep the legal system up to date. But in the day-to-day grind of the real world, even the most elegant software tends to crumble and suddenly reveal its hidden bugs. Like the advancing telephone system, the American legal system was certainly not ruined by its temporary crash; but for those caught under the weight of the collapsing system, life became a series of blackouts and anomalies. In order to understand why these weird events occurred, both in the world of technology and in the world of law, it's not enough to understand the merely technical problems. We will get to those; but first and foremost, we must try to understand the telephone, and the business of telephones, and the community of human beings that telephones have created. # Technologies have life cycles, like cities do, like institutions do, like laws and governments do. The first stage of any technology is the Question Mark, often known as the "Golden Vaporware" stage. At this early point, the technology is only a phantom, a mere gleam in the inventor's eye. One such inventor was a speech teacher and electrical tinkerer named Alexander Graham Bell. Bell's early inventions, while ingenious, failed to move the world. In 1863, the teenage Bell and his brother Melville made an artificial talking mechanism out of wood, rubber, gutta-percha, and tin. This weird device had a rubber-covered "tongue" made of movable wooden segments, with vibrating rubber "vocal cords," and rubber "lips" and "cheeks." While Melville puffed a bellows into a tin tube, imitating the lungs, young Alec Bell would manipulate the "lips," "teeth," and "tongue," causing the thing to emit high-pitched falsetto gibberish. Another would-be technical breakthrough was the Bell "phonautograph" of 1874, actually made out of a human cadaver's ear. Clamped into place on a tripod, this grisly gadget drew sound-wave images on smoked glass through a thin straw glued to its vibrating earbones. By 1875, Bell had learned to produce audible sounds--ugly shrieks and squawks--by using magnets, diaphragms, and electrical current. Most "Golden Vaporware" technologies go nowhere. But the second stage of technology is the Rising Star, or, the "Goofy Prototype," stage. The telephone, Bell's most ambitious gadget yet, reached this stage on March 10, 1876. On that great day, Alexander Graham Bell became the first person to transmit intelligible human speech electrically. As it happened, young Professor Bell, industriously tinkering in his Boston lab, had spattered his trousers with acid. His assistant, Mr. Watson, heard his cry for help--over Bell's experimental audio-telegraph. This was an event without precedent. Technologies in their "Goofy Prototype" stage rarely work very well. They're experimental, and therefore half- baked and rather frazzled. The prototype may be attractive and novel, and it does look as if it ought to be good for something-or-other. But nobody, including the inventor, is quite sure what. Inventors, and speculators, and pundits may have very firm ideas about its potential use, but those ideas are often very wrong. The natural habitat of the Goofy Prototype is in trade shows and in the popular press. Infant technologies need publicity and investment money like a tottering calf need milk. This was very true of Bell's machine. To raise research and development money, Bell toured with his device as a stage attraction. Contemporary press reports of the stage debut of the telephone showed pleased astonishment mixed with considerable dread. Bell's stage telephone was a large wooden box with a crude speaker-nozzle, the whole contraption about the size and shape of an overgrown Brownie camera. Its buzzing steel soundplate, pumped up by powerful electromagnets, was loud enough to fill an auditorium. Bell's assistant Mr. Watson, who could manage on the keyboards fairly well, kicked in by playing the organ from distant rooms, and, later, distant cities. This feat was considered marvellous, but very eerie indeed. Bell's original notion for the telephone, an idea promoted for a couple of years, was that it would become a mass medium. We might recognize Bell's idea today as something close to modern "cable radio." Telephones at a central source would transmit music, Sunday sermons, and important public speeches to a paying network of wired-up subscribers. At the time, most people thought this notion made good sense. In fact, Bell's idea was workable. In Hungary, this philosophy of the telephone was successfully put into everyday practice. In Budapest, for decades, from 1893 until after World War I, there was a government-run information service called "Telefon Hirmondo-." Hirmondo- was a centralized source of news and entertainment and culture, including stock reports, plays, concerts, and novels read aloud. At certain hours of the day, the phone would ring, you would plug in a loudspeaker for the use of the family, and Telefon Hirmondo- would be on the air--or rather, on the phone. Hirmondo- is dead tech today, but Hirmondo- might be considered a spiritual ancestor of the modern telephone-accessed computer data services, such as CompuServe, GEnie or Prodigy. The principle behind Hirmondo- is also not too far from computer "bulletin- board systems" or BBS's, which arrived in the late 1970s, spread rapidly across America, and will figure largely in this book. We are used to using telephones for individual person-to-person speech, because we are used to the Bell system. But this was just one possibility among many. Communication networks are very flexible and protean, especially when their hardware becomes sufficiently advanced. They can be put to all kinds of uses. And they have been-- and they will be. Bell's telephone was bound for glory, but this was a combination of political decisions, canny infighting in court, inspired industrial leadership, receptive local conditions and outright good luck. Much the same is true of communications systems today. As Bell and his backers struggled to install their newfangled system in the real world of nineteenth-century New England, they had to fight against skepticism and industrial rivalry. There was already a strong electrical communications network present in America: the telegraph. The head of the Western Union telegraph system dismissed Bell's prototype as "an electrical toy" and refused to buy the rights to Bell's patent. The telephone, it seemed, might be all right as a parlor entertainment-- but not for serious business. Telegrams, unlike mere telephones, left a permanent physical record of their messages. Telegrams, unlike telephones, could be answered whenever the recipient had time and convenience. And the telegram had a much longer distance-range than Bell's early telephone. These factors made telegraphy seem a much more sound and businesslike technology--at least to some. The telegraph system was huge, and well-entrenched. In 1876, the United States had 214,000 miles of telegraph wire, and 8500 telegraph offices. There were specialized telegraphs for businesses and stock traders, government, police and fire departments. And Bell's "toy" was best known as a stage-magic musical device. The third stage of technology is known as the "Cash Cow" stage. In the "cash cow" stage, a technology finds its place in the world, and matures, and becomes settled and productive. After a year or so, Alexander Graham Bell and his capitalist backers concluded that eerie music piped from nineteenth-century cyberspace was not the real selling-point of his invention. Instead, the telephone was about speech-- individual, personal speech, the human voice, human conversation and human interaction. The telephone was not to be managed from any centralized broadcast center. It was to be a personal, intimate technology. When you picked up a telephone, you were not absorbing the cold output of a machine--you were speaking to another human being. Once people realized this, their instinctive dread of the telephone as an eerie, unnatural device, swiftly vanished. A "telephone call" was not a "call" from a "telephone" itself, but a call from another human being, someone you would generally know and recognize. The real point was not what the machine could do for you (or to you), but what you yourself, a person and citizen, could do THROUGH the machine. This decision on the part of the young Bell Company was absolutely vital. The first telephone networks went up around Boston--mostly among the technically curious and the well-to-do (much the same segment of the American populace that, a hundred years later, would be buying personal computers). Entrenched backers of the telegraph continued to scoff. But in January 1878, a disaster made the telephone famous. A train crashed in Tarriffville, Connecticut. Forward-looking doctors in the nearby city of Hartford had had Bell's "speaking telephone" installed. An alert local druggist was able to telephone an entire community of local doctors, who rushed to the site to give aid. The disaster, as disasters do, aroused intense press coverage. The phone had proven its usefulness in the real world. After Tarriffville, the telephone network spread like crabgrass. By 1890 it was all over New England. By '93, out to Chicago. By '97, into Minnesota, Nebraska and Texas. By 1904 it was all over the continent. The telephone had become a mature technology. Professor Bell (now generally known as "Dr. Bell" despite his lack of a formal degree) became quite wealthy. He lost interest in the tedious day-to-day business muddle of the booming telephone network, and gratefully returned his attention to creatively hacking-around in his various laboratories, which were now much larger, better-ventilated, and gratifyingly better-equipped. Bell was never to have another great inventive success, though his speculations and prototypes anticipated fiber-optic transmission, manned flight, sonar, hydrofoil ships, tetrahedral construction, and Montessori education. The "decibel," the standard scientific measure of sound intensity, was named after Bell. Not all Bell's vaporware notions were inspired. He was fascinated by human eugenics. He also spent many years developing a weird personal system of astrophysics in which gravity did not exist. Bell was a definite eccentric. He was something of a hypochondriac, and throughout his life he habitually stayed up until four A.M., refusing to rise before noon. But Bell had accomplished a great feat; he was an idol of millions and his influence, wealth, and great personal charm, combined with his eccentricity, made him something of a loose cannon on deck. Bell maintained a thriving scientific salon in his winter mansion in Washington, D.C., which gave him considerable backstage influence in governmental and scientific circles. He was a major financial backer of the the magazines Science and National Geographic, both still flourishing today as important organs of the American scientific establishment. Bell's companion Thomas Watson, similarly wealthy and similarly odd, became the ardent political disciple of a 19th-century science-fiction writer and would-be social reformer, Edward Bellamy. Watson also trod the boards briefly as a Shakespearian actor. There would never be another Alexander Graham Bell, but in years to come there would be surprising numbers of people like him. Bell was a prototype of the high-tech entrepreneur. High-tech entrepreneurs will play a very prominent role in this book: not merely as technicians and businessmen, but as pioneers of the technical frontier, who can carry the power and prestige they derive from high-technology into the political and social arena. Like later entrepreneurs, Bell was fierce in defense of his own technological territory. As the telephone began to flourish, Bell was soon involved in violent lawsuits in the defense of his patents. Bell's Boston lawyers were excellent, however, and Bell himself, as an elocution teacher and gifted public speaker, was a devastatingly effective legal witness. In the eighteen years of Bell's patents, the Bell company was involved in six hundred separate lawsuits. The legal records printed filled 149 volumes. The Bell Company won every single suit. After Bell's exclusive patents expired, rival telephone companies sprang up all over America. Bell's company, American Bell Telephone, was soon in deep trouble. In 1907, American Bell Telephone fell into the hands of the rather sinister J.P. Morgan financial cartel, robber-baron speculators who dominated Wall Street. At this point, history might have taken a different turn. American might well have been served forever by a patchwork of locally owned telephone companies. Many state politicians and local businessmen considered this an excellent solution. But the new Bell holding company, American Telephone and Telegraph or AT&T, put in a new man at the helm, a visionary industrialist named Theodore Vail. Vail, a former Post Office manager, understood large organizations and had an innate feeling for the nature of large-scale communications. Vail quickly saw to it that AT&T seized the technological edge once again. The Pupin and Campbell "loading coil," and the deForest "audion," are both extinct technology today, but in 1913 they gave Vail's company the best LONG-DISTANCE lines ever built. By controlling long-distance--the links between, and over, and above the smaller local phone companies--AT&T swiftly gained the whip-hand over them, and was soon devouring them right and left. Vail plowed the profits back into research and development, starting the Bell tradition of huge-scale and brilliant industrial research. Technically and financially, AT&T gradually steamrollered the opposition. Independent telephone companies never became entirely extinct, and hundreds of them flourish today. But Vail's AT&T became the supreme communications company. At one point, Vail's AT&T bought Western Union itself, the very company that had derided Bell's telephone as a "toy." Vail thoroughly reformed Western Union's hidebound business along his modern principles; but when the federal government grew anxious at this centralization of power, Vail politely gave Western Union back. This centralizing process was not unique. Very similar events had happened in American steel, oil, and railroads. But AT&T, unlike the other companies, was to remain supreme. The monopoly robber-barons of those other industries were humbled and shattered by government trust-busting. Vail, the former Post Office official, was quite willing to accommodate the US government; in fact he would forge an active alliance with it. AT&T would become almost a wing of the American government, almost another Post Office--though not quite. AT&T would willingly submit to federal regulation, but in return, it would use the government's regulators as its own police, who would keep out competitors and assure the Bell system's profits and preeminence. This was the second birth--the political birth--of the American telephone system. Vail's arrangement was to persist, with vast success, for many decades, until 1982. His system was an odd kind of American industrial socialism. It was born at about the same time as Leninist Communism, and it lasted almost as long--and, it must be admitted, to considerably better effect. Vail's system worked. Except perhaps for aerospace, there has been no technology more thoroughly dominated by Americans than the telephone. The telephone was seen from the beginning as a quintessentially American technology. Bell's policy, and the policy of Theodore Vail, was a profoundly democratic policy of UNIVERSAL ACCESS. Vail's famous corporate slogan, "One Policy, One System, Universal Service," was a political slogan, with a very American ring to it. The American telephone was not to become the specialized tool of government or business, but a general public utility. At first, it was true, only the wealthy could afford private telephones, and Bell's company pursued the business markets primarily. The American phone system was a capitalist effort, meant to make money; it was not a charity. But from the first, almost all communities with telephone service had public telephones. And many stores--especially drugstores-- offered public use of their phones. You might not own a telephone-- but you could always get into the system, if you really needed to. There was nothing inevitable about this decision to make telephones "public" and "universal." Vail's system involved a profound act of trust in the public. This decision was a political one, informed by the basic values of the American republic. The situation might have been very different; and in other countries, under other systems, it certainly was. Joseph Stalin, for instance, vetoed plans for a Soviet phone system soon after the Bolshevik revolution. Stalin was certain that publicly accessible telephones would become instruments of anti-Soviet counterrevolution and conspiracy. (He was probably right.) When telephones did arrive in the Soviet Union, they would be instruments of Party authority, and always heavily tapped. (Alexander Solzhenitsyn's prison-camp novel The First Circle describes efforts to develop a phone system more suited to Stalinist purposes.) France, with its tradition of rational centralized government, had fought bitterly even against the electric telegraph, which seemed to the French entirely too anarchical and frivolous. For decades, nineteenth-century France communicated via the "visual telegraph," a nation-spanning, government-owned semaphore system of huge stone towers that signalled from hilltops, across vast distances, with big windmill-like arms. In 1846, one Dr. Barbay, a semaphore enthusiast, memorably uttered an early version of what might be called "the security expert's argument" against the open media. "No, the electric telegraph is not a sound invention. It will always be at the mercy of the slightest disruption, wild youths, drunkards, bums, etc. . . . The electric telegraph meets those destructive elements with only a few meters of wire over which supervision is impossible. A single man could, without being seen, cut the telegraph wires leading to Paris, and in twenty-four hours cut in ten different places the wires of the same line, without being arrested. The visual telegraph, on the contrary, has its towers, its high walls, its gates well-guarded from inside by strong armed men. Yes, I declare, substitution of the electric telegraph for the visual one is a dreadful measure, a truly idiotic act." Dr. Barbay and his high-security stone machines were eventually unsuccessful, but his argument-- that communication exists for the safety and convenience of the state, and must be carefully protected from the wild boys and the gutter rabble who might want to crash the system--would be heard again and again. When the French telephone system finally did arrive, its snarled inadequacy was to be notorious. Devotees of the American Bell System often recommended a trip to France, for skeptics. In Edwardian Britain, issues of class and privacy were a ball-and-chain for telephonic progress. It was considered outrageous that anyone--any wild fool off the street--could simply barge bellowing into one's office or home, preceded only by the ringing of a telephone bell. In Britain, phones were tolerated for the use of business, but private phones tended be stuffed away into closets, smoking rooms, or servants' quarters. Telephone operators were resented in Britain because they did not seem to "know their place." And no one of breeding would print a telephone number on a business card; this seemed a crass attempt to make the acquaintance of strangers. But phone access in America was to become a popular right; something like universal suffrage, only more so. American women could not yet vote when the phone system came through; yet from the beginning American women doted on the telephone. This "feminization" of the American telephone was often commented on by foreigners. Phones in America were not censored or stiff or formalized; they were social, private, intimate, and domestic. In America, Mother's Day is by far the busiest day of the year for the phone network. The early telephone companies, and especially AT&T, were among the foremost employers of American women. They employed the daughters of the American middle-class in great armies: in 1891, eight thousand women; by 1946, almost a quarter of a million. Women seemed to enjoy telephone work; it was respectable, it was steady, it paid fairly well as women's work went, and--not least-- it seemed a genuine contribution to the social good of the community. Women found Vail's ideal of public service attractive. This was especially true in rural areas, where women operators, running extensive rural party-lines, enjoyed considerable social power. The operator knew everyone on the party-line, and everyone knew her. Although Bell himself was an ardent suffragist, the telephone company did not employ women for the sake of advancing female liberation. AT&T did this for sound commercial reasons. The first telephone operators of the Bell system were not women, but teenage American boys. They were telegraphic messenger boys (a group about to be rendered technically obsolescent), who swept up around the phone office, dunned customers for bills, and made phone connections on the switchboard, all on the cheap. Within the very first year of operation, 1878, Bell's company learned a sharp lesson about combining teenage boys and telephone switchboards. Putting teenage boys in charge of the phone system brought swift and consistent disaster. Bell's chief engineer described them as "Wild Indians." The boys were openly rude to customers. They talked back to subscribers, saucing off, uttering facetious remarks, and generally giving lip. The rascals took Saint Patrick's Day off without permission. And worst of all they played clever tricks with the switchboard plugs: disconnecting calls, crossing lines so that customers found themselves talking to strangers, and so forth. This combination of power, technical mastery, and effective anonymity seemed to act like catnip on teenage boys. This wild-kid-on-the-wires phenomenon was not confined to the USA; from the beginning, the same was true of the British phone system. An early British commentator kindly remarked: "No doubt boys in their teens found the work not a little irksome, and it is also highly probable that under the early conditions of employment the adventurous and inquisitive spirits of which the average healthy boy of that age is possessed, were not always conducive to the best attention being given to the wants of the telephone subscribers." So the boys were flung off the system--or at least, deprived of control of the switchboard. But the "adventurous and inquisitive spirits" of the teenage boys would be heard from in the world of telephony, again and again. The fourth stage in the technological life-cycle is death: "the Dog," dead tech. The telephone has so far avoided this fate. On the contrary, it is thriving, still spreading, still evolving, and at increasing speed. The telephone has achieved a rare and exalted state for a technological artifact: it has become a HOUSEHOLD OBJECT. The telephone, like the clock, like pen and paper, like kitchen utensils and running water, has become a technology that is visible only by its absence. The telephone is technologically transparent. The global telephone system is the largest and most complex machine in the world, yet it is easy to use. More remarkable yet, the telephone is almost entirely physically safe for the user. For the average citizen in the 1870s, the telephone was weirder, more shocking, more "high-tech" and harder to comprehend, than the most outrageous stunts of advanced computing for us Americans in the 1990s. In trying to understand what is happening to us today, with our bulletin-board systems, direct overseas dialling, fiber-optic transmissions, computer viruses, hacking stunts, and a vivid tangle of new laws and new crimes, it is important to realize that our society has been through a similar challenge before-- and that, all in all, we did rather well by it. Bell's stage telephone seemed bizarre at first. But the sensations of weirdness vanished quickly, once people began to hear the familiar voices of relatives and friends, in their own homes on their own telephones. The telephone changed from a fearsome high-tech totem to an everyday pillar of human community. This has also happened, and is still happening, to computer networks. Computer networks such as NSFnet, BITnet, USENET, JANET, are technically advanced, intimidating, and much harder to use than telephones. Even the popular, commercial computer networks, such as GEnie, Prodigy, and CompuServe, cause much head-scratching and have been described as "user-hateful." Nevertheless they too are changing from fancy high-tech items into everyday sources of human community. The words "community" and "communication" have the same root. Wherever you put a communications network, you put a community as well. And whenever you TAKE AWAY that network--confiscate it, outlaw it, crash it, raise its price beyond affordability-- then you hurt that community. Communities will fight to defend themselves. People will fight harder and more bitterly to defend their communities, than they will fight to defend their own individual selves. And this is very true of the "electronic community" that arose around computer networks in the 1980s--or rather, the VARIOUS electronic communities, in telephony, law enforcement, computing, and the digital underground that, by the year 1990, were raiding, rallying, arresting, suing, jailing, fining and issuing angry manifestos. None of the events of 1990 were entirely new. Nothing happened in 1990 that did not have some kind of earlier and more understandable precedent. What gave the Hacker Crackdown its new sense of gravity and importance was the feeling--the COMMUNITY feeling-- that the political stakes had been raised; that trouble in cyberspace was no longer mere mischief or inconclusive skirmishing, but a genuine fight over genuine issues, a fight for community survival and the shape of the future. These electronic communities, having flourished throughout the 1980s, were becoming aware of themselves, and increasingly, becoming aware of other, rival communities. Worries were sprouting up right and left, with complaints, rumors, uneasy speculations. But it would take a catalyst, a shock, to make the new world evident. Like Bell's great publicity break, the Tarriffville Rail Disaster of January 1878, it would take a cause celebre. That cause was the AT&T Crash of January 15, 1990. After the Crash, the wounded and anxious telephone community would come out fighting hard. # The community of telephone technicians, engineers, operators and researchers is the oldest community in cyberspace. These are the veterans, the most developed group, the richest, the most respectable, in most ways the most powerful. Whole generations have come and gone since Alexander Graham Bell's day, but the community he founded survives; people work for the phone system today whose great-grandparents worked for the phone system. Its specialty magazines, such as Telephony, AT&T Technical Journal, Telephone Engineer and Management, are decades old; they make computer publications like Macworld and PC Week look like amateur johnny-come-latelies. And the phone companies take no back seat in high-technology, either. Other companies' industrial researchers may have won new markets; but the researchers of Bell Labs have won SEVEN NOBEL PRIZES. One potent device that Bell Labs originated, the transistor, has created entire GROUPS of industries. Bell Labs are world-famous for generating "a patent a day," and have even made vital discoveries in astronomy, physics and cosmology. Throughout its seventy-year history, "Ma Bell" was not so much a company as a way of life. Until the cataclysmic divestiture of the 1980s, Ma Bell was perhaps the ultimate maternalist mega-employer. The AT&T corporate image was the "gentle giant," "the voice with a smile," a vaguely socialist-realist world of cleanshaven linemen in shiny helmets and blandly pretty phone-girls in headsets and nylons. Bell System employees were famous as rock-ribbed Kiwanis and Rotary members, Little-League enthusiasts, school-board people. During the long heyday of Ma Bell, the Bell employee corps were nurtured top-to-bottom on a corporate ethos of public service. There was good money in Bell, but Bell was not ABOUT money; Bell used public relations, but never mere marketeering. People went into the Bell System for a good life, and they had a good life. But it was not mere money that led Bell people out in the midst of storms and earthquakes to fight with toppled phone-poles, to wade in flooded manholes, to pull the red-eyed graveyard-shift over collapsing switching-systems. The Bell ethic was the electrical equivalent of the postman's: neither rain, nor snow, nor gloom of night would stop these couriers. It is easy to be cynical about this, as it is easy to be cynical about any political or social system; but cynicism does not change the fact that thousands of people took these ideals very seriously. And some still do. The Bell ethos was about public service; and that was gratifying; but it was also about private POWER, and that was gratifying too. As a corporation, Bell was very special. Bell was privileged. Bell had snuggled up close to the state. In fact, Bell was as close to government as you could get in America and still make a whole lot of legitimate money. But unlike other companies, Bell was above and beyond the vulgar commercial fray. Through its regional operating companies, Bell was omnipresent, local, and intimate, all over America; but the central ivory towers at its corporate heart were the tallest and the ivoriest around. There were other phone companies in America, to be sure; the so-called independents. Rural cooperatives, mostly; small fry, mostly tolerated, sometimes warred upon. For many decades, "independent" American phone companies lived in fear and loathing of the official Bell monopoly (or the "Bell Octopus," as Ma Bell's nineteenth-century enemies described her in many angry newspaper manifestos). Some few of these independent entrepreneurs, while legally in the wrong, fought so bitterly against the Octopus that their illegal phone networks were cast into the street by Bell agents and publicly burned. The pure technical sweetness of the Bell System gave its operators, inventors and engineers a deeply satisfying sense of power and mastery. They had devoted their lives to improving this vast nation-spanning machine; over years, whole human lives, they had watched it improve and grow. It was like a great technological temple. They were an elite, and they knew it--even if others did not; in fact, they felt even more powerful BECAUSE others did not understand. The deep attraction of this sensation of elite technical power should never be underestimated. "Technical power" is not for everybody; for many people it simply has no charm at all. But for some people, it becomes the core of their lives. For a few, it is overwhelming, obsessive; it becomes something close to an addiction. People--especially clever teenage boys whose lives are otherwise mostly powerless and put-upon --love this sensation of secret power, and are willing to do all sorts of amazing things to achieve it. The technical POWER of electronics has motivated many strange acts detailed in this book, which would otherwise be inexplicable. So Bell had power beyond mere capitalism. The Bell service ethos worked, and was often propagandized, in a rather saccharine fashion. Over the decades, people slowly grew tired of this. And then, openly impatient with it. By the early 1980s, Ma Bell was to find herself with scarcely a real friend in the world. Vail's industrial socialism had become hopelessly out-of-fashion politically. Bell would be punished for that. And that punishment would fall harshly upon the people of the telephone community. # In 1983, Ma Bell was dismantled by federal court action. The pieces of Bell are now separate corporate entities. The core of the company became AT&T Communications, and also AT&T Industries (formerly Western Electric, Bell's manufacturing arm). AT&T Bell Labs became Bell Communications Research, Bellcore. Then there are the Regional Bell Operating Companies, or RBOCs, pronounced "arbocks." Bell was a titan and even these regional chunks are gigantic enterprises: Fortune 50 companies with plenty of wealth and power behind them. But the clean lines of "One Policy, One System, Universal Service" have been shattered, apparently forever. The "One Policy" of the early Reagan Administration was to shatter a system that smacked of noncompetitive socialism. Since that time, there has been no real telephone "policy" on the federal level. Despite the breakup, the remnants of Bell have never been set free to compete in the open marketplace. The RBOCs are still very heavily regulated, but not from the top. Instead, they struggle politically, economically and legally, in what seems an endless turmoil, in a patchwork of overlapping federal and state jurisdictions. Increasingly, like other major American corporations, the RBOCs are becoming multinational, acquiring important commercial interests in Europe, Latin America, and the Pacific Rim. But this, too, adds to their legal and political predicament. The people of what used to be Ma Bell are not happy about their fate. They feel ill-used. They might have been grudgingly willing to make a full transition to the free market; to become just companies amid other companies. But this never happened. Instead, AT&T and the RBOCS ("the Baby Bells") feel themselves wrenched from side to side by state regulators, by Congress, by the FCC, and especially by the federal court of Judge Harold Greene, the magistrate who ordered the Bell breakup and who has been the de facto czar of American telecommunications ever since 1983. Bell people feel that they exist in a kind of paralegal limbo today. They don't understand what's demanded of them. If it's "service," why aren't they treated like a public service? And if it's money, then why aren't they free to compete for it? No one seems to know, really. Those who claim to know keep changing their minds. Nobody in authority seems willing to grasp the nettle for once and all. Telephone people from other countries are amazed by the American telephone system today. Not that it works so well; for nowadays even the French telephone system works, more or less. They are amazed that the American telephone system STILL works AT ALL, under these strange conditions. Bell's "One System" of long-distance service is now only about eighty percent of a system, with the remainder held by Sprint, MCI, and the midget long-distance companies. Ugly wars over dubious corporate practices such as "slamming" (an underhanded method of snitching clients from rivals) break out with some regularity in the realm of long-distance service. The battle to break Bell's long-distance monopoly was long and ugly, and since the breakup the battlefield has not become much prettier. AT&T's famous shame-and-blame advertisements, which emphasized the shoddy work and purported ethical shadiness of their competitors, were much remarked on for their studied psychological cruelty. There is much bad blood in this industry, and much long-treasured resentment. AT&T's post-breakup corporate logo, a striped sphere, is known in the industry as the "Death Star" (a reference from the movie Star Wars, in which the "Death Star" was the spherical high- tech fortress of the harsh-breathing imperial ultra-baddie, Darth Vader.) Even AT&T employees are less than thrilled by the Death Star. A popular (though banned) T-shirt among AT&T employees bears the old-fashioned Bell logo of the Bell System, plus the newfangled striped sphere, with the before-and-after comments: "This is your brain--This is your brain on drugs!" AT&T made a very well-financed and determined effort to break into the personal computer market; it was disastrous, and telco computer experts are derisively known by their competitors as "the pole-climbers." AT&T and the Baby Bell arbocks still seem to have few friends. Under conditions of sharp commercial competition, a crash like that of January 15, 1990 was a major embarrassment to AT&T. It was a direct blow against their much-treasured reputation for reliability. Within days of the crash AT&T's Chief Executive Officer, Bob Allen, officially apologized, in terms of deeply pained humility: "AT&T had a major service disruption last Monday. We didn't live up to our own standards of quality, and we didn't live up to yours. It's as simple as that. And that's not acceptable to us. Or to you. . . . We understand how much people have come to depend upon AT&T service, so our AT&T Bell Laboratories scientists and our network engineers are doing everything possible to guard against a recurrence. . . . We know there's no way to make up for the inconvenience this problem may have caused you." Mr Allen's "open letter to customers" was printed in lavish ads all over the country: in the Wall Street Journal, USA Today, New York Times, Los Angeles Times, Chicago Tribune, Philadelphia Inquirer, San Francisco Chronicle Examiner, Boston Globe, Dallas Morning News, Detroit Free Press, Washington Post, Houston Chronicle, Cleveland Plain Dealer, Atlanta Journal Constitution, Minneapolis Star Tribune, St. Paul Pioneer Press Dispatch, Seattle Times/Post Intelligencer, Tacoma News Tribune, Miami Herald, Pittsburgh Press, St. Louis Post Dispatch, Denver Post, Phoenix Republic Gazette and Tampa Tribune. In another press release, AT&T went to some pains to suggest that this "software glitch" might have happened just as easily to MCI, although, in fact, it hadn't. (MCI's switching software was quite different from AT&T's--though not necessarily any safer.) AT&T also announced their plans to offer a rebate of service on Valentine's Day to make up for the loss during the Crash. "Every technical resource available, including Bell Labs scientists and engineers, has been devoted to assuring it will not occur again," the public was told. They were further assured that "The chances of a recurrence are small-- a problem of this magnitude never occurred before." In the meantime, however, police and corporate security maintained their own suspicions about "the chances of recurrence" and the real reason why a "problem of this magnitude" had appeared, seemingly out of nowhere. Police and security knew for a fact that hackers of unprecedented sophistication were illegally entering, and reprogramming, certain digital switching stations. Rumors of hidden "viruses" and secret "logic bombs" in the switches ran rampant in the underground, with much chortling over AT&T's predicament, and idle speculation over what unsung hacker genius was responsible for it. Some hackers, including police informants, were trying hard to finger one another as the true culprits of the Crash. Telco people found little comfort in objectivity when they contemplated these possibilities. It was just too close to the bone for them; it was embarrassing; it hurt so much, it was hard even to talk about. There has always been thieving and misbehavior in the phone system. There has always been trouble with the rival independents, and in the local loops. But to have such trouble in the core of the system, the long-distance switching stations, is a horrifying affair. To telco people, this is all the difference between finding roaches in your kitchen and big horrid sewer-rats in your bedroom. From the outside, to the average citizen, the telcos still seem gigantic and impersonal. The American public seems to regard them as something akin to Soviet apparats. Even when the telcos do their best corporate-citizen routine, subsidizing magnet high-schools and sponsoring news-shows on public television, they seem to win little except public suspicion. But from the inside, all this looks very different. There's harsh competition. A legal and political system that seems baffled and bored, when not actively hostile to telco interests. There's a loss of morale, a deep sensation of having somehow lost the upper hand. Technological change has caused a loss of data and revenue to other, newer forms of transmission. There's theft, and new forms of theft, of growing scale and boldness and sophistication. With all these factors, it was no surprise to see the telcos, large and small, break out in a litany of bitter complaint. In late '88 and throughout 1989, telco representatives grew shrill in their complaints to those few American law enforcement officials who make it their business to try to understand what telephone people are talking about. Telco security officials had discovered the computer- hacker underground, infiltrated it thoroughly, and become deeply alarmed at its growing expertise. Here they had found a target that was not only loathsome on its face, but clearly ripe for counterattack. Those bitter rivals: AT&T, MCI and Sprint--and a crowd of Baby Bells: PacBell, Bell South, Southwestern Bell, NYNEX, USWest, as well as the Bell research consortium Bellcore, and the independent long-distance carrier Mid-American-- all were to have their role in the great hacker dragnet of 1990. After years of being battered and pushed around, the telcos had, at least in a small way, seized the initiative again. After years of turmoil, telcos and government officials were once again to work smoothly in concert in defense of the System. Optimism blossomed; enthusiasm grew on all sides; the prospective taste of vengeance was sweet. # From the beginning--even before the crackdown had a name-- secrecy was a big problem. There were many good reasons for secrecy in the hacker crackdown. Hackers and code-thieves were wily prey, slinking back to their bedrooms and basements and destroying vital incriminating evidence at the first hint of trouble. Furthermore, the crimes themselves were heavily technical and difficult to describe, even to police--much less to the general public. When such crimes HAD been described intelligibly to the public, in the past, that very publicity had tended to INCREASE the crimes enormously. Telco officials, while painfully aware of the vulnerabilities of their systems, were anxious not to publicize those weaknesses. Experience showed them that those weaknesses, once discovered, would be pitilessly exploited by tens of thousands of people--not only by professional grifters and by underground hackers and phone phreaks, but by many otherwise more-or-less honest everyday folks, who regarded stealing service from the faceless, soulless "Phone Company" as a kind of harmless indoor sport. When it came to protecting their interests, telcos had long since given up on general public sympathy for "the Voice with a Smile." Nowadays the telco's "Voice" was very likely to be a computer's; and the American public showed much less of the proper respect and gratitude due the fine public service bequeathed them by Dr. Bell and Mr. Vail. The more efficient, high-tech, computerized, and impersonal the telcos became, it seemed, the more they were met by sullen public resentment and amoral greed. Telco officials wanted to punish the phone-phreak underground, in as public and exemplary a manner as possible. They wanted to make dire examples of the worst offenders, to seize the ringleaders and intimidate the small fry, to discourage and frighten the wacky hobbyists, and send the professional grifters to jail. To do all this, publicity was vital. Yet operational secrecy was even more so. If word got out that a nationwide crackdown was coming, the hackers might simply vanish; destroy the evidence, hide their computers, go to earth, and wait for the campaign to blow over. Even the young hackers were crafty and suspicious, and as for the professional grifters, they tended to split for the nearest state-line at the first sign of trouble. For the crackdown to work well, they would all have to be caught red-handed, swept upon suddenly, out of the blue, from every corner of the compass. And there was another strong motive for secrecy. In the worst-case scenario, a blown campaign might leave the telcos open to a devastating hacker counter-attack. If there were indeed hackers loose in America who had caused the January 15 Crash--if there were truly gifted hackers, loose in the nation's long-distance switching systems, and enraged or frightened by the crackdown--then they might react unpredictably to an attempt to collar them. Even if caught, they might have talented and vengeful friends still running around loose. Conceivably, it could turn ugly. Very ugly. In fact, it was hard to imagine just how ugly things might turn, given that possibility. Counter-attack from hackers was a genuine concern for the telcos. In point of fact, they would never suffer any such counter-attack. But in months to come, they would be at some pains to publicize this notion and to utter grim warnings about it. Still, that risk seemed well worth running. Better to run the risk of vengeful attacks, than to live at the mercy of potential crashers. Any cop would tell you that a protection racket had no real future. And publicity was such a useful thing. Corporate security officers, including telco security, generally work under conditions of great discretion. And corporate security officials do not make money for their companies. Their job is to PREVENT THE LOSS of money, which is much less glamorous than actually winning profits. If you are a corporate security official, and you do your job brilliantly, then nothing bad happens to your company at all. Because of this, you appear completely superfluous. This is one of the many unattractive aspects of security work. It's rare that these folks have the chance to draw some healthy attention to their own efforts. Publicity also served the interest of their friends in law enforcement. Public officials, including law enforcement officials, thrive by attracting favorable public interest. A brilliant prosecution in a matter of vital public interest can make the career of a prosecuting attorney. And for a police officer, good publicity opens the purses of the legislature; it may bring a citation, or a promotion, or at least a rise in status and the respect of one's peers. But to have both publicity and secrecy is to have one's cake and eat it too. In months to come, as we will show, this impossible act was to cause great pain to the agents of the crackdown. But early on, it seemed possible --maybe even likely--that the crackdown could successfully combine the best of both worlds. The ARREST of hackers would be heavily publicized. The actual DEEDS of the hackers, which were technically hard to explain and also a security risk, would be left decently obscured. The THREAT hackers posed would be heavily trumpeted; the likelihood of their actually committing such fearsome crimes would be left to the public's imagination. The spread of the computer underground, and its growing technical sophistication, would be heavily promoted; the actual hackers themselves, mostly bespectacled middle-class white suburban teenagers, would be denied any personal publicity. It does not seem to have occurred to any telco official that the hackers accused would demand a day in court; that journalists would smile upon the hackers as "good copy;" that wealthy high-tech entrepreneurs would offer moral and financial support to crackdown victims; that constitutional lawyers would show up with briefcases, frowning mightily. This possibility does not seem to have ever entered the game-plan. And even if it had, it probably would not have slowed the ferocious pursuit of a stolen phone-company document, mellifluously known as "Control Office Administration of Enhanced 911 Services for Special Services and Major Account Centers." In the chapters to follow, we will explore the worlds of police and the computer underground, and the large shadowy area where they overlap. But first, we must explore the battleground. Before we leave the world of the telcos, we must understand what a switching system actually is and how your telephone actually works. # To the average citizen, the idea of the telephone is represented by, well, a TELEPHONE: a device that you talk into. To a telco professional, however, the telephone itself is known, in lordly fashion, as a "subset." The "subset" in your house is a mere adjunct, a distant nerve ending, of the central switching stations, which are ranked in levels of heirarchy, up to the long-distance electronic switching stations, which are some of the largest computers on earth. Let us imagine that it is, say, 1925, before the introduction of computers, when the phone system was simpler and somewhat easier to grasp. Let's further imagine that you are Miss Leticia Luthor, a fictional operator for Ma Bell in New York City of the 20s. Basically, you, Miss Luthor, ARE the "switching system." You are sitting in front of a large vertical switchboard, known as a "cordboard," made of shiny wooden panels, with ten thousand metal-rimmed holes punched in them, known as jacks. The engineers would have put more holes into your switchboard, but ten thousand is as many as you can reach without actually having to get up out of your chair. Each of these ten thousand holes has its own little electric lightbulb, known as a "lamp," and its own neatly printed number code. With the ease of long habit, you are scanning your board for lit-up bulbs. This is what you do most of the time, so you are used to it. A lamp lights up. This means that the phone at the end of that line has been taken off the hook. Whenever a handset is taken off the hook, that closes a circuit inside the phone which then signals the local office, i.e. you, automatically. There might be somebody calling, or then again the phone might be simply off the hook, but this does not matter to you yet. The first thing you do, is record that number in your logbook, in your fine American public-school handwriting. This comes first, naturally, since it is done for billing purposes. You now take the plug of your answering cord, which goes directly to your headset, and plug it into the lit-up hole. "Operator," you announce. In operator's classes, before taking this job, you have been issued a large pamphlet full of canned operator's responses for all kinds of contingencies, which you had to memorize. You have also been trained in a proper non-regional, non-ethnic pronunciation and tone of voice. You rarely have the occasion to make any spontaneous remark to a customer, and in fact this is frowned upon (except out on the rural lines where people have time on their hands and get up to all kinds of mischief). A tough-sounding user's voice at the end of the line gives you a number. Immediately, you write that number down in your logbook, next to the caller's number, which you just wrote earlier. You then look and see if the number this guy wants is in fact on your switchboard, which it generally is, since it's generally a local call. Long distance costs so much that people use it sparingly. Only then do you pick up a calling-cord from a shelf at the base of the switchboard. This is a long elastic cord mounted on a kind of reel so that it will zip back in when you unplug it. There are a lot of cords down there, and when a bunch of them are out at once they look like a nest of snakes. Some of the girls think there are bugs living in those cable-holes. They're called "cable mites" and are supposed to bite your hands and give you rashes. You don't believe this, yourself. Gripping the head of your calling-cord, you slip the tip of it deftly into the sleeve of the jack for the called person. Not all the way in, though. You just touch it. If you hear a clicking sound, that means the line is busy and you can't put the call through. If the line is busy, you have to stick the calling-cord into a "busy-tone jack," which will give the guy a busy-tone. This way you don't have to talk to him yourself and absorb his natural human frustration. But the line isn't busy. So you pop the cord all the way in. Relay circuits in your board make the distant phone ring, and if somebody picks it up off the hook, then a phone conversation starts. You can hear this conversation on your answering cord, until you unplug it. In fact you could listen to the whole conversation if you wanted, but this is sternly frowned upon by management, and frankly, when you've overheard one, you've pretty much heard 'em all. You can tell how long the conversation lasts by the glow of the calling-cord's lamp, down on the calling-cord's shelf. When it's over, you unplug and the calling-cord zips back into place. Having done this stuff a few hundred thousand times, you become quite good at it. In fact you're plugging, and connecting, and disconnecting, ten, twenty, forty cords at a time. It's a manual handicraft, really, quite satisfying in a way, rather like weaving on an upright loom. Should a long-distance call come up, it would be different, but not all that different. Instead of connecting the call through your own local switchboard, you have to go up the hierarchy, onto the long-distance lines, known as "trunklines." Depending on how far the call goes, it may have to work its way through a whole series of operators, which can take quite a while. The caller doesn't wait on the line while this complex process is negotiated across the country by the gaggle of operators. Instead, the caller hangs up, and you call him back yourself when the call has finally worked its way through. After four or five years of this work, you get married, and you have to quit your job, this being the natural order of womanhood in the American 1920s. The phone company has to train somebody else--maybe two people, since the phone system has grown somewhat in the meantime. And this costs money. In fact, to use any kind of human being as a switching system is a very expensive proposition. Eight thousand Leticia Luthors would be bad enough, but a quarter of a million of them is a military-scale proposition and makes drastic measures in automation financially worthwhile. Although the phone system continues to grow today, the number of human beings employed by telcos has been dropping steadily for years. Phone "operators" now deal with nothing but unusual contingencies, all routine operations having been shrugged off onto machines. Consequently, telephone operators are considerably less machine-like nowadays, and have been known to have accents and actual character in their voices. When you reach a human operator today, the operators are rather more "human" than they were in Leticia's day--but on the other hand, human beings in the phone system are much harder to reach in the first place. Over the first half of the twentieth century, "electromechanical" switching systems of growing complexity were cautiously introduced into the phone system. In certain backwaters, some of these hybrid systems are still in use. But after 1965, the phone system began to go completely electronic, and this is by far the dominant mode today. Electromechanical systems have "crossbars," and "brushes," and other large moving mechanical parts, which, while faster and cheaper than Leticia, are still slow, and tend to wear out fairly quickly. But fully electronic systems are inscribed on silicon chips, and are lightning-fast, very cheap, and quite durable. They are much cheaper to maintain than even the best electromechanical systems, and they fit into half the space. And with every year, the silicon chip grows smaller, faster, and cheaper yet. Best of all, automated electronics work around the clock and don't have salaries or health insurance. There are, however, quite serious drawbacks to the use of computer-chips. When they do break down, it is a daunting challenge to figure out what the heck has gone wrong with them. A broken cordboard generally had a problem in it big enough to see. A broken chip has invisible, microscopic faults. And the faults in bad software can be so subtle as to be practically theological. If you want a mechanical system to do something new, then you must travel to where it is, and pull pieces out of it, and wire in new pieces. This costs money. However, if you want a chip to do something new, all you have to do is change its software, which is easy, fast and dirt-cheap. You don't even have to see the chip to change its program. Even if you did see the chip, it wouldn't look like much. A chip with program X doesn't look one whit different from a chip with program Y. With the proper codes and sequences, and access to specialized phone-lines, you can change electronic switching systems all over America from anywhere you please. And so can other people. If they know how, and if they want to, they can sneak into a microchip via the special phonelines and diddle with it, leaving no physical trace at all. If they broke into the operator's station and held Leticia at gunpoint, that would be very obvious. If they broke into a telco building and went after an electromechanical switch with a toolbelt, that would at least leave many traces. But people can do all manner of amazing things to computer switches just by typing on a keyboard, and keyboards are everywhere today. The extent of this vulnerability is deep, dark, broad, almost mind-boggling, and yet this is a basic, primal fact of life about any computer on a network. Security experts over the past twenty years have insisted, with growing urgency, that this basic vulnerability of computers represents an entirely new level of risk, of unknown but obviously dire potential to society. And they are right. An electronic switching station does pretty much everything Letitia did, except in nanoseconds and on a much larger scale. Compared to Miss Luthor's ten thousand jacks, even a primitive 1ESS switching computer, 60s vintage, has a 128,000 lines. And the current AT&T system of choice is the monstrous fifth-generation 5ESS. An Electronic Switching Station can scan every line on its "board" in a tenth of a second, and it does this over and over, tirelessly, around the clock. Instead of eyes, it uses "ferrod scanners" to check the condition of local lines and trunks. Instead of hands, it has "signal distributors," "central pulse distributors," "magnetic latching relays," and "reed switches," which complete and break the calls. Instead of a brain, it has a "central processor." Instead of an instruction manual, it has a program. Instead of a handwritten logbook for recording and billing calls, it has magnetic tapes. And it never has to talk to anybody. Everything a customer might say to it is done by punching the direct-dial tone buttons on your subset. Although an Electronic Switching Station can't talk, it does need an interface, some way to relate to its, er, employers. This interface is known as the "master control center." (This interface might be better known simply as "the interface," since it doesn't actually "control" phone calls directly. However, a term like "Master Control Center" is just the kind of rhetoric that telco maintenance engineers--and hackers--find particularly satisfying.) Using the master control center, a phone engineer can test local and trunk lines for malfunctions. He (rarely she) can check various alarm displays, measure traffic on the lines, examine the records of telephone usage and the charges for those calls, and change the programming. And, of course, anybody else who gets into the master control center by remote control can also do these things, if he (rarely she) has managed to figure them out, or, more likely, has somehow swiped the knowledge from people who already know. In 1989 and 1990, one particular RBOC, BellSouth, which felt particularly troubled, spent a purported $1.2 million on computer security. Some think it spent as much as two million, if you count all the associated costs. Two million dollars is still very little compared to the great cost-saving utility of telephonic computer systems. Unfortunately, computers are also stupid. Unlike human beings, computers possess the truly profound stupidity of the inanimate. In the 1960s, in the first shocks of spreading computerization, there was much easy talk about the stupidity of computers-- how they could "only follow the program" and were rigidly required to do "only what they were told." There has been rather less talk about the stupidity of computers since they began to achieve grandmaster status in chess tournaments, and to manifest many other impressive forms of apparent cleverness. Nevertheless, computers STILL are profoundly brittle and stupid; they are simply vastly more subtle in their stupidity and brittleness. The computers of the 1990s are much more reliable in their components than earlier computer systems, but they are also called upon to do far more complex things, under far more challenging conditions. On a basic mathematical level, every single line of a software program offers a chance for some possible screwup. Software does not sit still when it works; it "runs," it interacts with itself and with its own inputs and outputs. By analogy, it stretches like putty into millions of possible shapes and conditions, so many shapes that they can never all be successfully tested, not even in the lifespan of the universe. Sometimes the putty snaps. The stuff we call "software" is not like anything that human society is used to thinking about. Software is something like a machine, and something like mathematics, and something like language, and something like thought, and art, and information. . . . But software is not in fact any of those other things. The protean quality of software is one of the great sources of its fascination. It also makes software very powerful, very subtle, very unpredictable, and very risky. Some software is bad and buggy. Some is "robust," even "bulletproof." The best software is that which has been tested by thousands of users under thousands of different conditions, over years. It is then known as "stable." This does NOT mean that the software is now flawless, free of bugs. It generally means that there are plenty of bugs in it, but the bugs are well-identified and fairly well understood. There is simply no way to assure that software is free of flaws. Though software is mathematical in nature, it cannot by "proven" like a mathematical theorem; software is more like language, with inherent ambiguities, with different definitions, different assumptions, different levels of meaning that can conflict. Human beings can manage, more or less, with human language because we can catch the gist of it. Computers, despite years of effort in "artificial intelligence," have proven spectacularly bad in "catching the gist" of anything at all. The tiniest bit of semantic grit may still bring the mightiest computer tumbling down. One of the most hazardous things you can do to a computer program is try to improve it--to try to make it safer. Software "patches" represent new, untried un-"stable" software, which is by definition riskier. The modern telephone system has come to depend, utterly and irretrievably, upon software. And the System Crash of January 15, 1990, was caused by an IMPROVEMENT in software. Or rather, an ATTEMPTED improvement. As it happened, the problem itself--the problem per se--took this form. A piece of telco software had been written in C language, a standard language of the telco field. Within the C software was a long "do. . .while" construct. The "do. . .while" construct contained a "switch" statement. The "switch" statement contained an "if" clause. The "if" clause contained a "break." The "break" was SUPPOSED to "break" the "if clause." Instead, the "break" broke the "switch" statement. That was the problem, the actual reason why people picking up phones on January 15, 1990, could not talk to one another. Or at least, that was the subtle, abstract, cyberspatial seed of the problem. This is how the problem manifested itself from the realm of programming into the realm of real life. The System 7 software for AT&T's 4ESS switching station, the "Generic 44E14 Central Office Switch Software," had been extensively tested, and was considered very stable. By the end of 1989, eighty of AT&T's switching systems nationwide had been programmed with the new software. Cautiously, thirty-four stations were left to run the slower, less-capable System 6, because AT&T suspected there might be shakedown problems with the new and unprecedently sophisticated System 7 network. The stations with System 7 were programmed to switch over to a backup net in case of any problems. In mid-December 1989, however, a new high-velocity, high-security software patch was distributed to each of the 4ESS switches that would enable them to switch over even more quickly, making the System 7 network that much more secure. Unfortunately, every one of these 4ESS switches was now in possession of a small but deadly flaw. In order to maintain the network, switches must monitor the condition of other switches--whether they are up and running, whether they have temporarily shut down, whether they are overloaded and in need of assistance, and so forth. The new software helped control this bookkeeping function by monitoring the status calls from other switches. It only takes four to six seconds for a troubled 4ESS switch to rid itself of all its calls, drop everything temporarily, and re-boot its software from scratch. Starting over from scratch will generally rid the switch of any software problems that may have developed in the course of running the system. Bugs that arise will be simply wiped out by this process. It is a clever idea. This process of automatically re-booting from scratch is known as the "normal fault recovery routine." Since AT&T's software is in fact exceptionally stable, systems rarely have to go into "fault recovery" in the first place; but AT&T has always boasted of its "real world" reliability, and this tactic is a belt-and-suspenders routine. The 4ESS switch used its new software to monitor its fellow switches as they recovered from faults. As other switches came back on line after recovery, they would send their "OK" signals to the switch. The switch would make a little note to that effect in its "status map," recognizing that the fellow switch was back and ready to go, and should be sent some calls and put back to regular work. Unfortunately, while it was busy bookkeeping with the status map, the tiny flaw in the brand-new software came into play. The flaw caused the 4ESS switch to interact, subtly but drastically, with incoming telephone calls from human users. If--and only if-- two incoming phone-calls happened to hit the switch within a hundredth of a second, then a small patch of data would be garbled by the flaw. But the switch had been programmed to monitor itself constantly for any possible damage to its data. When the switch perceived that its data had been somehow garbled, then it too would go down, for swift repairs to its software. It would signal its fellow switches not to send any more work. It would go into the fault-recovery mode for four to six seconds. And then the switch would be fine again, and would send out its "OK, ready for work" signal. However, the "OK, ready for work" signal was the VERY THING THAT HAD CAUSED THE SWITCH TO GO DOWN IN THE FIRST PLACE. And ALL the System 7 switches had the same flaw in their status-map software. As soon as they stopped to make the bookkeeping note that their fellow switch was "OK," then they too would become vulnerable to the slight chance that two phone-calls would hit them within a hundredth of a second. At approximately 2:25 P.M. EST on Monday, January 15, one of AT&T's 4ESS toll switching systems in New York City had an actual, legitimate, minor problem. It went into fault recovery routines, announced "I'm going down," then announced, "I'm back, I'm OK." And this cheery message then blasted throughout the network to many of its fellow 4ESS switches. Many of the switches, at first, completely escaped trouble. These lucky switches were not hit by the coincidence of two phone calls within a hundredth of a second. Their software did not fail--at first. But three switches-- in Atlanta, St. Louis, and Detroit--were unlucky, and were caught with their hands full. And they went down. And they came back up, almost immediately. And they too began to broadcast the lethal message that they, too, were "OK" again, activating the lurking software bug in yet other switches. As more and more switches did have that bit of bad luck and collapsed, the call-traffic became more and more densely packed in the remaining switches, which were groaning to keep up with the load. And of course, as the calls became more densely packed, the switches were MUCH MORE LIKELY to be hit twice within a hundredth of a second. It only took four seconds for a switch to get well. There was no PHYSICAL damage of any kind to the switches, after all. Physically, they were working perfectly. This situation was "only" a software problem. But the 4ESS switches were leaping up and down every four to six seconds, in a virulent spreading wave all over America, in utter, manic, mechanical stupidity. They kept KNOCKING one another down with their contagious "OK" messages. It took about ten minutes for the chain reaction to cripple the network. Even then, switches would periodically luck-out and manage to resume their normal work. Many calls--millions of them--were managing to get through. But millions weren't. The switching stations that used System 6 were not directly affected. Thanks to these old-fashioned switches, AT&T's national system avoided complete collapse. This fact also made it clear to engineers that System 7 was at fault. Bell Labs engineers, working feverishly in New Jersey, Illinois, and Ohio, first tried their entire repertoire of standard network remedies on the malfunctioning System 7. None of the remedies worked, of course, because nothing like this had ever happened to any phone system before. By cutting out the backup safety network entirely, they were able to reduce the frenzy of "OK" messages by about half. The system then began to recover, as the chain reaction slowed. By 11:30 P.M. on Monday January 15, sweating engineers on the midnight shift breathed a sigh of relief as the last switch cleared-up. By Tuesday they were pulling all the brand-new 4ESS software and replacing it with an earlier version of System 7. If these had been human operators, rather than computers at work, someone would simply have eventually stopped screaming. It would have been OBVIOUS that the situation was not "OK," and common sense would have kicked in. Humans possess common sense-- at least to some extent. Computers simply don't. On the other hand, computers can handle hundreds of calls per second. Humans simply can't. If every single human being in America worked for the phone company, we couldn't match the performance of digital switches: direct-dialling, three-way calling, speed-calling, call- waiting, Caller ID, all the rest of the cornucopia of digital bounty. Replacing computers with operators is simply not an option any more. And yet we still, anachronistically, expect humans to be running our phone system. It is hard for us to understand that we have sacrificed huge amounts of initiative and control to senseless yet powerful machines. When the phones fail, we want somebody to be responsible. We want somebody to blame. When the Crash of January 15 happened, the American populace was simply not prepared to understand that enormous landslides in cyberspace, like the Crash itself, can happen, and can be nobody's fault in particular. It was easier to believe, maybe even in some odd way more reassuring to believe, that some evil person, or evil group, had done this to us. "Hackers" had done it. With a virus. A trojan horse. A software bomb. A dirty plot of some kind. People believed this, responsible people. In 1990, they were looking hard for evidence to confirm their heartfelt suspicions. And they would look in a lot of places. Come 1991, however, the outlines of an apparent new reality would begin to emerge from the fog. On July 1 and 2, 1991, computer-software collapses in telephone switching stations disrupted service in Washington DC, Pittsburgh, Los Angeles and San Francisco. Once again, seemingly minor maintenance problems had crippled the digital System 7. About twelve million people were affected in the Crash of July 1, 1991. Said the New York Times Service: "Telephone company executives and federal regulators said they were not ruling out the possibility of sabotage by computer hackers, but most seemed to think the problems stemmed from some unknown defect in the software running the networks." And sure enough, within the week, a red-faced software company, DSC Communications Corporation of Plano, Texas, owned up to "glitches" in the "signal transfer point" software that DSC had designed for Bell Atlantic and Pacific Bell. The immediate cause of the July 1 Crash was a single mistyped character: one tiny typographical flaw in one single line of the software. One mistyped letter, in one single line, had deprived the nation's capital of phone service. It was not particularly surprising that this tiny flaw had escaped attention: a typical System 7 station requires TEN MILLION lines of code. On Tuesday, September 17, 1991, came the most spectacular outage yet. This case had nothing to do with software failures--at least, not directly. Instead, a group of AT&T's switching stations in New York City had simply run out of electrical power and shut down cold. Their back-up batteries had failed. Automatic warning systems were supposed to warn of the loss of battery power, but those automatic systems had failed as well. This time, Kennedy, La Guardia, and Newark airports all had their voice and data communications cut. This horrifying event was particularly ironic, as attacks on airport computers by hackers had long been a standard nightmare scenario, much trumpeted by computer-security experts who feared the computer underground. There had even been a Hollywood thriller about sinister hackers ruining airport computers--DIE HARD II. Now AT&T itself had crippled airports with computer malfunctions-- not just one airport, but three at once, some of the busiest in the world. Air traffic came to a standstill throughout the Greater New York area, causing more than 500 flights to be cancelled, in a spreading wave all over America and even into Europe. Another 500 or so flights were delayed, affecting, all in all, about 85,000 passengers. (One of these passengers was the chairman of the Federal Communications Commission.) Stranded passengers in New York and New Jersey were further infuriated to discover that they could not even manage to make a long distance phone call, to explain their delay to loved ones or business associates. Thanks to the crash, about four and a half million domestic calls, and half a million international calls, failed to get through. The September 17 NYC Crash, unlike the previous ones, involved not a whisper of "hacker" misdeeds. On the contrary, by 1991, AT&T itself was suffering much of the vilification that had formerly been directed at hackers. Congressmen were grumbling. So were state and federal regulators. And so was the press. For their part, ancient rival MCI took out snide full-page newspaper ads in New York, offering their own long-distance services for the "next time that AT&T goes down." "You wouldn't find a classy company like AT&T using such advertising," protested AT&T Chairman Robert Allen, unconvincingly. Once again, out came the full-page AT&T apologies in newspapers, apologies for "an inexcusable culmination of both human and mechanical failure." (This time, however, AT&T offered no discount on later calls. Unkind critics suggested that AT&T were worried about setting any precedent for refunding the financial losses caused by telephone crashes.) Industry journals asked publicly if AT&T was "asleep at the switch." The telephone network, America's purported marvel of high-tech reliability, had gone down three times in 18 months. Fortune magazine listed the Crash of September 17 among the "Biggest Business Goofs of 1991," cruelly parodying AT&T's ad campaign in an article entitled "AT&T Wants You Back (Safely On the Ground, God Willing)." Why had those New York switching systems simply run out of power? Because no human being had attended to the alarm system. Why did the alarm systems blare automatically, without any human being noticing? Because the three telco technicians who SHOULD have been listening were absent from their stations in the power-room, on another floor of the building--attending a training class. A training class about the alarm systems for the power room! "Crashing the System" was no longer "unprecedented" by late 1991. On the contrary, it no longer even seemed an oddity. By 1991, it was clear that all the policemen in the world could no longer "protect" the phone system from crashes. By far the worst crashes the system had ever had, had been inflicted, by the system, upon ITSELF. And this time nobody was making cocksure statements that this was an anomaly, something that would never happen again. By 1991 the System's defenders had met their nebulous Enemy, and the Enemy was--the System. PART TWO: THE DIGITAL UNDERGROUND The date was May 9, 1990. The Pope was touring Mexico City. Hustlers from the Medellin Cartel were trying to buy black-market Stinger missiles in Florida. On the comics page, Doonesbury character Andy was dying of AIDS. And then. . .a highly unusual item whose novelty and calculated rhetoric won it headscratching attention in newspapers all over America. The US Attorney's office in Phoenix, Arizona, had issued a press release announcing a nationwide law enforcement crackdown against "illegal computer hacking activities." The sweep was officially known as "Operation Sundevil." Eight paragraphs in the press release gave the bare facts: twenty-seven search warrants carried out on May 8, with three arrests, and a hundred and fifty agents on the prowl in "twelve" cities across America. (Different counts in local press reports yielded "thirteen," "fourteen," and "sixteen" cities.) Officials estimated that criminal losses of revenue to telephone companies "may run into millions of dollars." Credit for the Sundevil investigations was taken by the US Secret Service, Assistant US Attorney Tim Holtzen of Phoenix, and the Assistant Attorney General of Arizona, Gail Thackeray. The prepared remarks of Garry M. Jenkins, appearing in a U.S. Department of Justice press release, were of particular interest. Mr. Jenkins was the Assistant Director of the US Secret Service, and the highest-ranking federal official to take any direct public role in the hacker crackdown of 1990. "Today, the Secret Service is sending a clear message to those computer hackers who have decided to violate the laws of this nation in the mistaken belief that they can successfully avoid detection by hiding behind the relative anonymity of their computer terminals. (. . .) "Underground groups have been formed for the purpose of exchanging information relevant to their criminal activities. These groups often communicate with each other through message systems between computers called `bulletin boards.' "Our experience shows that many computer hacker suspects are no longer misguided teenagers, mischievously playing games with their computers in their bedrooms. Some are now high tech computer operators using computers to engage in unlawful conduct." Who were these "underground groups" and "high-tech operators?" Where had they come from? What did they want? Who WERE they? Were they "mischievous?" Were they dangerous? How had "misguided teenagers" managed to alarm the United States Secret Service? And just how widespread was this sort of thing? Of all the major players in the Hacker Crackdown: the phone companies, law enforcement, the civil libertarians, and the "hackers" themselves-- the "hackers" are by far the most mysterious, by far the hardest to understand, by far the WEIRDEST. Not only are "hackers" novel in their activities, but they come in a variety of odd subcultures, with a variety of languages, motives and values. The earliest proto-hackers were probably those unsung mischievous telegraph boys who were summarily fired by the Bell Company in 1878. Legitimate "hackers," those computer enthusiasts who are independent-minded but law-abiding, generally trace their spiritual ancestry to elite technical universities, especially M.I.T. and Stanford, in the 1960s. But the genuine roots of the modern hacker UNDERGROUND can probably be traced most successfully to a now much-obscured hippie anarchist movement known as the Yippies. The Yippies, who took their name from the largely fictional "Youth International Party," carried out a loud and lively policy of surrealistic subversion and outrageous political mischief. Their basic tenets were flagrant sexual promiscuity, open and copious drug use, the political overthrow of any powermonger over thirty years of age, and an immediate end to the war in Vietnam, by any means necessary, including the psychic levitation of the Pentagon. The two most visible Yippies were Abbie Hoffman and Jerry Rubin. Rubin eventually became a Wall Street broker. Hoffman, ardently sought by federal authorities, went into hiding for seven years, in Mexico, France, and the United States. While on the lam, Hoffman continued to write and publish, with help from sympathizers in the American anarcho-leftist underground. Mostly, Hoffman survived through false ID and odd jobs. Eventually he underwent facial plastic surgery and adopted an entirely new identity as one "Barry Freed." After surrendering himself to authorities in 1980, Hoffman spent a year in prison on a cocaine conviction. Hoffman's worldview grew much darker as the glory days of the 1960s faded. In 1989, he purportedly committed suicide, under odd and, to some, rather suspicious circumstances. Abbie Hoffman is said to have caused the Federal Bureau of Investigation to amass the single largest investigation file ever opened on an individual American citizen. (If this is true, it is still questionable whether the FBI regarded Abbie Hoffman a serious public threat--quite possibly, his file was enormous simply because Hoffman left colorful legendry wherever he went). He was a gifted publicist, who regarded electronic media as both playground and weapon. He actively enjoyed manipulating network TV and other gullible, image-hungry media, with various weird lies, mindboggling rumors, impersonation scams, and other sinister distortions, all absolutely guaranteed to upset cops, Presidential candidates, and federal judges. Hoffman's most famous work was a book self-reflexively known as STEAL THIS BOOK, which publicized a number of methods by which young, penniless hippie agitators might live off the fat of a system supported by humorless drones. STEAL THIS BOOK, whose title urged readers to damage the very means of distribution which had put it into their hands, might be described as a spiritual ancestor of a computer virus. Hoffman, like many a later conspirator, made extensive use of pay-phones for his agitation work--in his case, generally through the use of cheap brass washers as coin-slugs. During the Vietnam War, there was a federal surtax imposed on telephone service; Hoffman and his cohorts could, and did, argue that in systematically stealing phone service they were engaging in civil disobedience: virtuously denying tax funds to an illegal and immoral war. But this thin veil of decency was soon dropped entirely. Ripping-off the System found its own justification in deep alienation and a basic outlaw contempt for conventional bourgeois values. Ingenious, vaguely politicized varieties of rip-off, which might be described as "anarchy by convenience," became very popular in Yippie circles, and because rip-off was so useful, it was to survive the Yippie movement itself. In the early 1970s, it required fairly limited expertise and ingenuity to cheat payphones, to divert "free" electricity and gas service, or to rob vending machines and parking meters for handy pocket change. It also required a conspiracy to spread this knowledge, and the gall and nerve actually to commit petty theft, but the Yippies had these qualifications in plenty. In June 1971, Abbie Hoffman and a telephone enthusiast sarcastically known as "Al Bell" began publishing a newsletter called Youth International Party Line. This newsletter was dedicated to collating and spreading Yippie rip-off techniques, especially of phones, to the joy of the freewheeling underground and the insensate rage of all straight people. As a political tactic, phone-service theft ensured that Yippie advocates would always have ready access to the long-distance telephone as a medium, despite the Yippies' chronic lack of organization, discipline, money, or even a steady home address. PARTY LINE was run out of Greenwich Village for a couple of years, then "Al Bell" more or less defected from the faltering ranks of Yippiedom, changing the newsletter's name to TAP or Technical Assistance Program. After the Vietnam War ended, the steam began leaking rapidly out of American radical dissent. But by this time, "Bell" and his dozen or so core contributors had the bit between their teeth, and had begun to derive tremendous gut-level satisfaction from the sensation of pure TECHNICAL POWER. TAP articles, once highly politicized, became pitilessly jargonized and technical, in homage or parody to the Bell System's own technical documents, which TAP studied closely, gutted, and reproduced without permission. The TAP elite revelled in gloating possession of the specialized knowledge necessary to beat the system. "Al Bell" dropped out of the game by the late 70s, and "Tom Edison" took over; TAP readers (some 1400 of them, all told) now began to show more interest in telex switches and the growing phenomenon of computer systems. In 1983, "Tom Edison" had his computer stolen and his house set on fire by an arsonist. This was an eventually mortal blow to TAP (though the legendary name was to be resurrected in 1990 by a young Kentuckian computer-outlaw named "Predat0r.") # Ever since telephones began to make money, there have been people willing to rob and defraud phone companies. The legions of petty phone thieves vastly outnumber those "phone phreaks" who "explore the system" for the sake of the intellectual challenge. The New York metropolitan area (long in the vanguard of American crime) claims over 150,000 physical attacks on pay telephones every year! Studied carefully, a modern payphone reveals itself as a little fortress, carefully designed and redesigned over generations, to resist coin-slugs, zaps of electricity, chunks of coin-shaped ice, prybars, magnets, lockpicks, blasting caps. Public pay- phones must survive in a world of unfriendly, greedy people, and a modern payphone is as exquisitely evolved as a cactus. Because the phone network pre-dates the computer network, the scofflaws known as "phone phreaks" pre-date the scofflaws known as "computer hackers." In practice, today, the line between "phreaking" and "hacking" is very blurred, just as the distinction between telephones and computers has blurred. The phone system has been digitized, and computers have learned to "talk" over phone-lines. What's worse--and this was the point of the Mr. Jenkins of the Secret Service--some hackers have learned to steal, and some thieves have learned to hack. Despite the blurring, one can still draw a few useful behavioral distinctions between "phreaks" and "hackers." Hackers are intensely interested in the "system" per se, and enjoy relating to machines. "Phreaks" are more social, manipulating the system in a rough-and-ready fashion in order to get through to other human beings, fast, cheap and under the table. Phone phreaks love nothing so much as "bridges," illegal conference calls of ten or twelve chatting conspirators, seaboard to seaboard, lasting for many hours --and running, of course, on somebody else's tab, preferably a large corporation's. As phone-phreak conferences wear on, people drop out (or simply leave the phone off the hook, while they sashay off to work or school or babysitting), and new people are phoned up and invited to join in, from some other continent, if possible. Technical trivia, boasts, brags, lies, head-trip deceptions, weird rumors, and cruel gossip are all freely exchanged. The lowest rung of phone-phreaking is the theft of telephone access codes. Charging a phone call to somebody else's stolen number is, of course, a pig-easy way of stealing phone service, requiring practically no technical expertise. This practice has been very widespread, especially among lonely people without much money who are far from home. Code theft has flourished especially in college dorms, military bases, and, notoriously, among roadies for rock bands. Of late, code theft has spread very rapidly among Third Worlders in the US, who pile up enormous unpaid long-distance bills to the Caribbean, South America, and Pakistan. The simplest way to steal phone-codes is simply to look over a victim's shoulder as he punches-in his own code-number on a public payphone. This technique is known as "shoulder-surfing," and is especially common in airports, bus terminals, and train stations. The code is then sold by the thief for a few dollars. The buyer abusing the code has no computer expertise, but calls his Mom in New York, Kingston or Caracas and runs up a huge bill with impunity. The losses from this primitive phreaking activity are far, far greater than the monetary losses caused by computer-intruding hackers. In the mid-to-late 1980s, until the introduction of sterner telco security measures, COMPUTERIZED code theft worked like a charm, and was virtually omnipresent throughout the digital underground, among phreaks and hackers alike. This was accomplished through programming one's computer to try random code numbers over the telephone until one of them worked. Simple programs to do this were widely available in the underground; a computer running all night was likely to come up with a dozen or so useful hits. This could be repeated week after week until one had a large library of stolen codes. Nowadays, the computerized dialling of hundreds of numbers can be detected within hours and swiftly traced. If a stolen code is repeatedly abused, this too can be detected within a few hours. But for years in the 1980s, the publication of stolen codes was a kind of elementary etiquette for fledgling hackers. The simplest way to establish your bona-fides as a raider was to steal a code through repeated random dialling and offer it to the "community" for use. Codes could be both stolen, and used, simply and easily from the safety of one's own bedroom, with very little fear of detection or punishment. Before computers and their phone-line modems entered American homes in gigantic numbers, phone phreaks had their own special telecommunications hardware gadget, the famous "blue box." This fraud device (now rendered increasingly useless by the digital evolution of the phone system) could trick switching systems into granting free access to long-distance lines. It did this by mimicking the system's own signal, a tone of 2600 hertz. Steven Jobs and Steve Wozniak, the founders of Apple Computer, Inc., once dabbled in selling blue-boxes in college dorms in California. For many, in the early days of phreaking, blue-boxing was scarcely perceived as "theft," but rather as a fun (if sneaky) way to use excess phone capacity harmlessly. After all, the long-distance lines were JUST SITTING THERE. . . . Whom did it hurt, really? If you're not DAMAGING the system, and you're not USING UP ANY TANGIBLE RESOURCE, and if nobody FINDS OUT what you did, then what real harm have you done? What exactly HAVE you "stolen," anyway? If a tree falls in the forest and nobody hears it, how much is the noise worth? Even now this remains a rather dicey question. Blue-boxing was no joke to the phone companies, however. Indeed, when Ramparts magazine, a radical publication in California, printed the wiring schematics necessary to create a mute box in June 1972, the magazine was seized by police and Pacific Bell phone-company officials. The mute box, a blue-box variant, allowed its user to receive long-distance calls free of charge to the caller. This device was closely described in a Ramparts article wryly titled "Regulating the Phone Company In Your Home." Publication of this article was held to be in violation of Californian State Penal Code section 502.7, which outlaws ownership of wire-fraud devices and the selling of "plans or instructions for any instrument, apparatus, or device intended to avoid telephone toll charges." Issues of Ramparts were recalled or seized on the newsstands, and the resultant loss of income helped put the magazine out of business. This was an ominous precedent for free-expression issues, but the telco's crushing of a radical-fringe magazine passed without serious challenge at the time. Even in the freewheeling California 1970s, it was widely felt that there was something sacrosanct about what the phone company knew; that the telco had a legal and moral right to protect itself by shutting off the flow of such illicit information. Most telco information was so "specialized" that it would scarcely be understood by any honest member of the public. If not published, it would not be missed. To print such material did not seem part of the legitimate role of a free press. In 1990 there would be a similar telco-inspired attack on the electronic phreak/hacking "magazine" Phrack. The Phrack legal case became a central issue in the Hacker Crackdown, and gave rise to great controversy. Phrack would also be shut down, for a time, at least, but this time both the telcos and their law-enforcement allies would pay a much larger price for their actions. The Phrack case will be examined in detail, later. Phone-phreaking as a social practice is still very much alive at this moment. Today, phone-phreaking is thriving much more vigorously than the better-known and worse-feared practice of "computer hacking." New forms of phreaking are spreading rapidly, following new vulnerabilities in sophisticated phone services. Cellular phones are especially vulnerable; their chips can be re-programmed to present a false caller ID and avoid billing. Doing so also avoids police tapping, making cellular-phone abuse a favorite among drug-dealers. "Call-sell operations" using pirate cellular phones can, and have, been run right out of the backs of cars, which move from "cell" to "cell" in the local phone system, retailing stolen long-distance service, like some kind of demented electronic version of the neighborhood ice-cream truck. Private branch-exchange phone systems in large corporations can be penetrated; phreaks dial-up a local company, enter its internal phone-system, hack it, then use the company's own PBX system to dial back out over the public network, causing the company to be stuck with the resulting long-distance bill. This technique is known as "diverting." "Diverting" can be very costly, especially because phreaks tend to travel in packs and never stop talking. Perhaps the worst by-product of this "PBX fraud" is that victim companies and telcos have sued one another over the financial responsibility for the stolen calls, thus enriching not only shabby phreaks but well-paid lawyers. "Voice-mail systems" can also be abused; phreaks can seize their own sections of these sophisticated electronic answering machines, and use them for trading codes or knowledge of illegal techniques. Voice-mail abuse does not hurt the company directly, but finding supposedly empty slots in your company's answering machine all crammed with phreaks eagerly chattering and hey-duding one another in impenetrable jargon can cause sensations of almost mystical repulsion and dread. Worse yet, phreaks have sometimes been known to react truculently to attempts to "clean up" the voice-mail system. Rather than humbly acquiescing to being thrown out of their playground, they may very well call up the company officials at work (or at home) and loudly demand free voice-mail addresses of their very own. Such bullying is taken very seriously by spooked victims. Acts of phreak revenge against straight people are rare, but voice-mail systems are especially tempting and vulnerable, and an infestation of angry phreaks in one's voice-mail system is no joke. They can erase legitimate messages; or spy on private messages; or harass users with recorded taunts and obscenities. They've even been known to seize control of voice-mail security, and lock out legitimate users, or even shut down the system entirely. Cellular phone-calls, cordless phones, and ship-to-shore telephony can all be monitored by various forms of radio; this kind of "passive monitoring" is spreading explosively today. Technically eavesdropping on other people's cordless and cellular phone-calls is the fastest-growing area in phreaking today. This practice strongly appeals to the lust for power and conveys gratifying sensations of technical superiority over the eavesdropping victim. Monitoring is rife with all manner of tempting evil mischief. Simple prurient snooping is by far the most common activity. But credit-card numbers unwarily spoken over the phone can be recorded, stolen and used. And tapping people's phone-calls (whether through active telephone taps or passive radio monitors) does lend itself conveniently to activities like blackmail, industrial espionage, and political dirty tricks. It should be repeated that telecommunications fraud, the theft of phone service, causes vastly greater monetary losses than the practice of entering into computers by stealth. Hackers are mostly young suburban American white males, and exist in their hundreds--but "phreaks" come from both sexes and from many nationalities, ages and ethnic backgrounds, and are flourishing in the thousands. # The term "hacker" has had an unfortunate history. This book, The Hacker Crackdown, has little to say about "hacking" in its finer, original sense. The term can signify the free-wheeling intellectual exploration of the highest and deepest potential of computer systems. Hacking can describe the determination to make access to computers and information as free and open as possible. Hacking can involve the heartfelt conviction that beauty can be found in computers, that the fine aesthetic in a perfect program can liberate the mind and spirit. This is "hacking" as it was defined in Steven Levy's much-praised history of the pioneer computer milieu, Hackers, published in 1984. Hackers of all kinds are absolutely soaked through with heroic anti-bureaucratic sentiment. Hackers long for recognition as a praiseworthy cultural archetype, the postmodern electronic equivalent of the cowboy and mountain man. Whether they deserve such a reputation is something for history to decide. But many hackers-- including those outlaw hackers who are computer intruders, and whose activities are defined as criminal--actually attempt to LIVE UP TO this techno-cowboy reputation. And given that electronics and telecommunications are still largely unexplored territories, there is simply NO TELLING what hackers might uncover. For some people, this freedom is the very breath of oxygen, the inventive spontaneity that makes life worth living and that flings open doors to marvellous possibility and individual empowerment. But for many people --and increasingly so--the hacker is an ominous figure, a smart-aleck sociopath ready to burst out of his basement wilderness and savage other people's lives for his own anarchical convenience. Any form of power without responsibility, without direct and formal checks and balances, is frightening to people-- and reasonably so. It should be frankly admitted that hackers ARE frightening, and that the basis of this fear is not irrational. Fear of hackers goes well beyond the fear of merely criminal activity. Subversion and manipulation of the phone system is an act with disturbing political overtones. In America, computers and telephones are potent symbols of organized authority and the technocratic business elite. But there is an element in American culture that has always strongly rebelled against these symbols; rebelled against all large industrial computers and all phone companies. A certain anarchical tinge deep in the American soul delights in causing confusion and pain to all bureaucracies, including technological ones. There is sometimes malice and vandalism in this attitude, but it is a deep and cherished part of the American national character. The outlaw, the rebel, the rugged individual, the pioneer, the sturdy Jeffersonian yeoman, the private citizen resisting interference in his pursuit of happiness--these are figures that all Americans recognize, and that many will strongly applaud and defend. Many scrupulously law-abiding citizens today do cutting-edge work with electronics--work that has already had tremendous social influence and will have much more in years to come. In all truth, these talented, hardworking, law-abiding, mature, adult people are far more disturbing to the peace and order of the current status quo than any scofflaw group of romantic teenage punk kids. These law-abiding hackers have the power, ability, and willingness to influence other people's lives quite unpredictably. They have means, motive, and opportunity to meddle drastically with the American social order. When corralled into governments, universities, or large multinational companies, and forced to follow rulebooks and wear suits and ties, they at least have some conventional halters on their freedom of action. But when loosed alone, or in small groups, and fired by imagination and the entrepreneurial spirit, they can move mountains--causing landslides that will likely crash directly into your office and living room. These people, as a class, instinctively recognize that a public, politicized attack on hackers will eventually spread to them-- that the term "hacker," once demonized, might be used to knock their hands off the levers of power and choke them out of existence. There are hackers today who fiercely and publicly resist any besmirching of the noble title of hacker. Naturally and understandably, they deeply resent the attack on their values implicit in using the word "hacker" as a synonym for computer-criminal. This book, sadly but in my opinion unavoidably, rather adds to the degradation of the term. It concerns itself mostly with "hacking" in its commonest latter-day definition, i.e., intruding into computer systems by stealth and without permission. The term "hacking" is used routinely today by almost all law enforcement officials with any professional interest in computer fraud and abuse. American police describe almost any crime committed with, by, through, or against a computer as hacking. Most importantly, "hacker" is what computer-intruders choose to call THEMSELVES. Nobody who "hacks" into systems willingly describes himself (rarely, herself) as a "computer intruder," "computer trespasser," "cracker," "wormer," "darkside hacker" or "high tech street gangster." Several other demeaning terms have been invented in the hope that the press and public will leave the original sense of the word alone. But few people actually use these terms. (I exempt the term "cyberpunk," which a few hackers and law enforcement people actually do use. The term "cyberpunk" is drawn from literary criticism and has some odd and unlikely resonances, but, like hacker, cyberpunk too has become a criminal pejorative today.) In any case, breaking into computer systems was hardly alien to the original hacker tradition. The first tottering systems of the 1960s required fairly extensive internal surgery merely to function day-by-day. Their users "invaded" the deepest, most arcane recesses of their operating software almost as a matter of routine. "Computer security" in these early, primitive systems was at best an afterthought. What security there was, was entirely physical, for it was assumed that anyone allowed near this expensive, arcane hardware would be a fully qualified professional expert. In a campus environment, though, this meant that grad students, teaching assistants, undergraduates, and eventually, all manner of dropouts and hangers-on ended up accessing and often running the works. Universities, even modern universities, are not in the business of maintaining security over information. On the contrary, universities, as institutions, pre-date the "information economy" by many centuries and are not- for-profit cultural entities, whose reason for existence (purportedly) is to discover truth, codify it through techniques of scholarship, and then teach it. Universities are meant to PASS THE TORCH OF CIVILIZATION, not just download data into student skulls, and the values of the academic community are strongly at odds with those of all would-be information empires. Teachers at all levels, from kindergarten up, have proven to be shameless and persistent software and data pirates. Universities do not merely "leak information" but vigorously broadcast free thought. This clash of values has been fraught with controversy. Many hackers of the 1960s remember their professional apprenticeship as a long guerilla war against the uptight mainframe-computer "information priesthood." These computer-hungry youngsters had to struggle hard for access to computing power, and many of them were not above certain, er, shortcuts. But, over the years, this practice freed computing from the sterile reserve of lab-coated technocrats and was largely responsible for the explosive growth of computing in general society--especially PERSONAL computing. Access to technical power acted like catnip on certain of these youngsters. Most of the basic techniques of computer intrusion: password cracking, trapdoors, backdoors, trojan horses--were invented in college environments in the 1960s, in the early days of network computing. Some off-the-cuff experience at computer intrusion was to be in the informal resume of most "hackers" and many future industry giants. Outside of the tiny cult of computer enthusiasts, few people thought much about the implications of "breaking into" computers. This sort of activity had not yet been publicized, much less criminalized. In the 1960s, definitions of "property" and "privacy" had not yet been extended to cyberspace. Computers were not yet indispensable to society. There were no vast databanks of vulnerable, proprietary information stored in computers, which might be accessed, copied without permission, erased, altered, or sabotaged. The stakes were low in the early days--but they grew every year, exponentially, as computers themselves grew. By the 1990s, commercial and political pressures had become overwhelming, and they broke the social boundaries of the hacking subculture. Hacking had become too important to be left to the hackers. Society was now forced to tackle the intangible nature of cyberspace-as-property, cyberspace as privately-owned unreal-estate. In the new, severe, responsible, high-stakes context of the "Information Society" of the 1990s, "hacking" was called into question. What did it mean to break into a computer without permission and use its computational power, or look around inside its files without hurting anything? What were computer-intruding hackers, anyway--how should society, and the law, best define their actions? Were they just BROWSERS, harmless intellectual explorers? Were they VOYEURS, snoops, invaders of privacy? Should they be sternly treated as potential AGENTS OF ESPIONAGE, or perhaps as INDUSTRIAL SPIES? Or were they best defined as TRESPASSERS, a very common teenage misdemeanor? Was hacking THEFT OF SERVICE? (After all, intruders were getting someone else's computer to carry out their orders, without permission and without paying). Was hacking FRAUD? Maybe it was best described as IMPERSONATION. The commonest mode of computer intrusion was (and is) to swipe or snoop somebody else's password, and then enter the computer in the guise of another person--who is commonly stuck with the blame and the bills. Perhaps a medical metaphor was better--hackers should be defined as "sick," as COMPUTER ADDICTS unable to control their irresponsible, compulsive behavior. But these weighty assessments meant little to the people who were actually being judged. From inside the underground world of hacking itself, all these perceptions seem quaint, wrongheaded, stupid, or meaningless. The most important self-perception of underground hackers-- from the 1960s, right through to the present day--is that they are an ELITE. The day-to-day struggle in the underground is not over sociological definitions--who cares?--but for power, knowledge, and status among one's peers. When you are a hacker, it is your own inner conviction of your elite status that enables you to break, or let us say "transcend," the rules. It is not that ALL rules go by the board. The rules habitually broken by hackers are UNIMPORTANT rules--the rules of dopey greedhead telco bureaucrats and pig-ignorant government pests. Hackers have their OWN rules, which separate behavior which is cool and elite, from behavior which is rodentlike, stupid and losing. These "rules," however, are mostly unwritten and enforced by peer pressure and tribal feeling. Like all rules that depend on the unspoken conviction that everybody else is a good old boy, these rules are ripe for abuse. The mechanisms of hacker peer- pressure, "teletrials" and ostracism, are rarely used and rarely work. Back-stabbing slander, threats, and electronic harassment are also freely employed in down-and-dirty intrahacker feuds, but this rarely forces a rival out of the scene entirely. The only real solution for the problem of an utterly losing, treacherous and rodentlike hacker is to TURN HIM IN TO THE POLICE. Unlike the Mafia or Medellin Cartel, the hacker elite cannot simply execute the bigmouths, creeps and troublemakers among their ranks, so they turn one another in with astonishing frequency. There is no tradition of silence or OMERTA in the hacker underworld. Hackers can be shy, even reclusive, but when they do talk, hackers tend to brag, boast and strut. Almost everything hackers do is INVISIBLE; if they don't brag, boast, and strut about it, then NOBODY WILL EVER KNOW. If you don't have something to brag, boast, and strut about, then nobody in the underground will recognize you and favor you with vital cooperation and respect. The way to win a solid reputation in the underground is by telling other hackers things that could only have been learned by exceptional cunning and stealth. Forbidden knowledge, therefore, is the basic currency of the digital underground, like seashells among Trobriand Islanders. Hackers hoard this knowledge, and dwell upon it obsessively, and refine it, and bargain with it, and talk and talk about it. Many hackers even suffer from a strange obsession to TEACH-- to spread the ethos and the knowledge of the digital underground. They'll do this even when it gains them no particular advantage and presents a grave personal risk. And when that risk catches up with them, they will go right on teaching and preaching--to a new audience this time, their interrogators from law enforcement. Almost every hacker arrested tells everything he knows-- all about his friends, his mentors, his disciples--legends, threats, horror stories, dire rumors, gossip, hallucinations. This is, of course, convenient for law enforcement--except when law enforcement begins to believe hacker legendry. Phone phreaks are unique among criminals in their willingness to call up law enforcement officials--in the office, at their homes-- and give them an extended piece of their mind. It is hard not to interpret this as BEGGING FOR ARREST, and in fact it is an act of incredible foolhardiness. Police are naturally nettled by these acts of chutzpah and will go well out of their way to bust these flaunting idiots. But it can also be interpreted as a product of a world-view so elitist, so closed and hermetic, that electronic police are simply not perceived as "police," but rather as ENEMY PHONE PHREAKS who should be scolded into behaving "decently." Hackers at their most grandiloquent perceive themselves as the elite pioneers of a new electronic world. Attempts to make them obey the democratically established laws of contemporary American society are seen as repression and persecution. After all, they argue, if Alexander Graham Bell had gone along with the rules of the Western Union telegraph company, there would have been no telephones. If Jobs and Wozniak had believed that IBM was the be-all and end-all, there would have been no personal computers. If Benjamin Franklin and Thomas Jefferson had tried to "work within the system" there would have been no United States. Not only do hackers privately believe this as an article of faith, but they have been known to write ardent manifestos about it. Here are some revealing excerpts from an especially vivid hacker manifesto: "The Techno-Revolution" by "Dr. Crash," which appeared in electronic form in Phrack Volume 1, Issue 6, Phile 3. "To fully explain the true motives behind hacking, we must first take a quick look into the past. In the 1960s, a group of MIT students built the first modern computer system. This wild, rebellious group of young men were the first to bear the name `hackers.' The systems that they developed were intended to be used to solve world problems and to benefit all of mankind. "As we can see, this has not been the case. The computer system has been solely in the hands of big businesses and the government. The wonderful device meant to enrich life has become a weapon which dehumanizes people. To the government and large businesses, people are no more than disk space, and the government doesn't use computers to arrange aid for the poor, but to control nuclear death weapons. The average American can only have access to a small microcomputer which is worth only a fraction of what they pay for it. The businesses keep the true state-of-the-art equipment away from the people behind a steel wall of incredibly high prices and bureaucracy. It is because of this state of affairs that hacking was born. (. . .) "Of course, the government doesn't want the monopoly of technology broken, so they have outlawed hacking and arrest anyone who is caught. (. . .) The phone company is another example of technology abused and kept from people with high prices. (. . .) "Hackers often find that their existing equipment, due to the monopoly tactics of computer companies, is inefficient for their purposes. Due to the exorbitantly high prices, it is impossible to legally purchase the necessary equipment. This need has given still another segment of the fight: Credit Carding. Carding is a way of obtaining the necessary goods without paying for them. It is again due to the companies' stupidity that Carding is so easy, and shows that the world's businesses are in the hands of those with considerably less technical know-how than we, the hackers. (. . .) "Hacking must continue. We must train newcomers to the art of hacking. (. . . .) And whatever you do, continue the fight. Whether you know it or not, if you are a hacker, you are a revolutionary. Don't worry, you're on the right side." The defense of "carding" is rare. Most hackers regard credit-card theft as "poison" to the underground, a sleazy and immoral effort that, worse yet, is hard to get away with. Nevertheless, manifestos advocating credit-card theft, the deliberate crashing of computer systems, and even acts of violent physical destruction such as vandalism and arson do exist in the underground. These boasts and threats are taken quite seriously by the police. And not every hacker is an abstract, Platonic computer-nerd. Some few are quite experienced at picking locks, robbing phone-trucks, and breaking and entering buildings. Hackers vary in their degree of hatred for authority and the violence of their rhetoric. But, at a bottom line, they are scofflaws. They don't regard the current rules of electronic behavior as respectable efforts to preserve law and order and protect public safety. They regard these laws as immoral efforts by soulless corporations to protect their profit margins and to crush dissidents. "Stupid" people, including police, businessmen, politicians, and journalists, simply have no right to judge the actions of those possessed of genius, techno-revolutionary intentions, and technical expertise. # Hackers are generally teenagers and college kids not engaged in earning a living. They often come from fairly well-to-do middle-class backgrounds, and are markedly anti-materialistic (except, that is, when it comes to computer equipment). Anyone motivated by greed for mere money (as opposed to the greed for power, knowledge and status) is swiftly written-off as a narrow- minded breadhead whose interests can only be corrupt and contemptible. Having grown up in the 1970s and 1980s, the young Bohemians of the digital underground regard straight society as awash in plutocratic corruption, where everyone from the President down is for sale and whoever has the gold makes the rules. Interestingly, there's a funhouse-mirror image of this attitude on the other side of the conflict. The police are also one of the most markedly anti-materialistic groups in American society, motivated not by mere money but by ideals of service, justice, esprit-de-corps, and, of course, their own brand of specialized knowledge and power. Remarkably, the propaganda war between cops and hackers has always involved angry allegations that the other side is trying to make a sleazy buck. Hackers consistently sneer that anti-phreak prosecutors are angling for cushy jobs as telco lawyers and that computer-crime police are aiming to cash in later as well-paid computer-security consultants in the private sector. For their part, police publicly conflate all hacking crimes with robbing payphones with crowbars. Allegations of "monetary losses" from computer intrusion are notoriously inflated. The act of illicitly copying a document from a computer is morally equated with directly robbing a company of, say, half a million dollars. The teenage computer intruder in possession of this "proprietary" document has certainly not sold it for such a sum, would likely have little idea how to sell it at all, and quite probably doesn't even understand what he has. He has not made a cent in profit from his felony but is still morally equated with a thief who has robbed the church poorbox and lit out for Brazil. Police want to believe that all hackers are thieves. It is a tortuous and almost unbearable act for the American justice system to put people in jail because they want to learn things which are forbidden for them to know. In an American context, almost any pretext for punishment is better than jailing people to protect certain restricted kinds of information. Nevertheless, POLICING INFORMATION is part and parcel of the struggle against hackers. This dilemma is well exemplified by the remarkable activities of "Emmanuel Goldstein," editor and publisher of a print magazine known as 2600: The Hacker Quarterly. Goldstein was an English major at Long Island's State University of New York in the '70s, when he became involved with the local college radio station. His growing interest in electronics caused him to drift into Yippie TAP circles and thus into the digital underground, where he became a self-described techno-rat. His magazine publishes techniques of computer intrusion and telephone "exploration" as well as gloating exposes of telco misdeeds and governmental failings. Goldstein lives quietly and very privately in a large, crumbling Victorian mansion in Setauket, New York. The seaside house is decorated with telco decals, chunks of driftwood, and the basic bric-a-brac of a hippie crash-pad. He is unmarried, mildly unkempt, and survives mostly on TV dinners and turkey-stuffing eaten straight out of the bag. Goldstein is a man of considerable charm and fluency, with a brief, disarming smile and the kind of pitiless, stubborn, thoroughly recidivist integrity that America's electronic police find genuinely alarming. Goldstein took his nom-de-plume, or "handle," from a character in Orwell's 1984, which may be taken, correctly, as a symptom of the gravity of his sociopolitical worldview. He is not himself a practicing computer intruder, though he vigorously abets these actions, especially when they are pursued against large corporations or governmental agencies. Nor is he a thief, for he loudly scorns mere theft of phone service, in favor of "exploring and manipulating the system." He is probably best described and understood as a DISSIDENT. Weirdly, Goldstein is living in modern America under conditions very similar to those of former East European intellectual dissidents. In other words, he flagrantly espouses a value-system that is deeply and irrevocably opposed to the system of those in power and the police. The values in 2600 are generally expressed in terms that are ironic, sarcastic, paradoxical, or just downright confused. But there's no mistaking their radically anti-authoritarian tenor. 2600 holds that technical power and specialized knowledge, of any kind obtainable, belong by right in the hands of those individuals brave and bold enough to discover them--by whatever means necessary. Devices, laws, or systems that forbid access, and the free spread of knowledge, are provocations that any free and self-respecting hacker should relentlessly attack. The "privacy" of governments, corporations and other soulless technocratic organizations should never be protected at the expense of the liberty and free initiative of the individual techno-rat. However, in our contemporary workaday world, both governments and corporations are very anxious indeed to police information which is secret, proprietary, restricted, confidential, copyrighted, patented, hazardous, illegal, unethical, embarrassing, or otherwise sensitive. This makes Goldstein persona non grata, and his philosophy a threat. Very little about the conditions of Goldstein's daily life would astonish, say, Vaclav Havel. (We may note in passing that President Havel once had his word-processor confiscated by the Czechoslovak police.) Goldstein lives by SAMIZDAT, acting semi-openly as a data-center for the underground, while challenging the powers-that-be to abide by their own stated rules: freedom of speech and the First Amendment. Goldstein thoroughly looks and acts the part of techno-rat, with shoulder-length ringlets and a piratical black fisherman's-cap set at a rakish angle. He often shows up like Banquo's ghost at meetings of computer professionals, where he listens quietly, half-smiling and taking thorough notes. Computer professionals generally meet publicly, and find it very difficult to rid themselves of Goldstein and his ilk without extralegal and unconstitutional actions. Sympathizers, many of them quite respectable people with responsible jobs, admire Goldstein's attitude and surreptitiously pass him information. An unknown but presumably large proportion of Goldstein's 2,000-plus readership are telco security personnel and police, who are forced to subscribe to 2600 to stay abreast of new developments in hacking. They thus find themselves PAYING THIS GUY'S RENT while grinding their teeth in anguish, a situation that would have delighted Abbie Hoffman (one of Goldstein's few idols). Goldstein is probably the best-known public representative of the hacker underground today, and certainly the best-hated. Police regard him as a Fagin, a corrupter of youth, and speak of him with untempered loathing. He is quite an accomplished gadfly. After the Martin Luther King Day Crash of 1990, Goldstein, for instance, adeptly rubbed salt into the wound in the pages of 2600. "Yeah, it was fun for the phone phreaks as we watched the network crumble," he admitted cheerfully. "But it was also an ominous sign of what's to come. . . . Some AT&T people, aided by well-meaning but ignorant media, were spreading the notion that many companies had the same software and therefore could face the same problem someday. Wrong. This was entirely an AT&T software deficiency. Of course, other companies could face entirely DIFFERENT software problems. But then, so too could AT&T." After a technical discussion of the system's failings, the Long Island techno-rat went on to offer thoughtful criticism to the gigantic multinational's hundreds of professionally qualified engineers. "What we don't know is how a major force in communications like AT&T could be so sloppy. What happened to backups? Sure, computer systems go down all the time, but people making phone calls are not the same as people logging on to computers. We must make that distinction. It's not acceptable for the phone system or any other essential service to `go down.' If we continue to trust technology without understanding it, we can look forward to many variations on this theme. "AT&T owes it to its customers to be prepared to INSTANTLY switch to another network if something strange and unpredictable starts occurring. The news here isn't so much the failure of a computer program, but the failure of AT&T's entire structure." The very idea of this. . . . this PERSON. . . . offering "advice" about "AT&T's entire structure" is more than some people can easily bear. How dare this near-criminal dictate what is or isn't "acceptable" behavior from AT&T? Especially when he's publishing, in the very same issue, detailed schematic diagrams for creating various switching-network signalling tones unavailable to the public. "See what happens when you drop a `silver box' tone or two down your local exchange or through different long distance service carriers," advises 2600 contributor "Mr. Upsetter" in "How To Build a Signal Box." "If you experiment systematically and keep good records, you will surely discover something interesting." This is, of course, the scientific method, generally regarded as a praiseworthy activity and one of the flowers of modern civilization. One can indeed learn a great deal with this sort of structured intellectual activity. Telco employees regard this mode of "exploration" as akin to flinging sticks of dynamite into their pond to see what lives on the bottom. 2600 has been published consistently since 1984. It has also run a bulletin board computer system, printed 2600 T-shirts, taken fax calls. . . . The Spring 1991 issue has an interesting announcement on page 45: "We just discovered an extra set of wires attached to our fax line and heading up the pole. (They've since been clipped.) Your faxes to us and to anyone else could be monitored." In the worldview of 2600, the tiny band of techno-rat brothers (rarely, sisters) are a beseiged vanguard of the truly free and honest. The rest of the world is a maelstrom of corporate crime and high-level governmental corruption, occasionally tempered with well-meaning ignorance. To read a few issues in a row is to enter a nightmare akin to Solzhenitsyn's, somewhat tempered by the fact that 2600 is often extremely funny. Goldstein did not become a target of the Hacker Crackdown, though he protested loudly, eloquently, and publicly about it, and it added considerably to his fame. It was not that he is not regarded as dangerous, because he is so regarded. Goldstein has had brushes with the law in the past: in 1985, a 2600 bulletin board computer was seized by the FBI, and some software on it was formally declared "a burglary tool in the form of a computer program." But Goldstein escaped direct repression in 1990, because his magazine is printed on paper, and recognized as subject to Constitutional freedom of the press protection. As was seen in the Ramparts case, this is far from an absolute guarantee. Still, as a practical matter, shutting down 2600 by court-order would create so much legal hassle that it is simply unfeasible, at least for the present. Throughout 1990, both Goldstein and his magazine were peevishly thriving. Instead, the Crackdown of 1990 would concern itself with the computerized version of forbidden data. The crackdown itself, first and foremost, was about BULLETIN BOARD SYSTEMS. Bulletin Board Systems, most often known by the ugly and un-pluralizable acronym "BBS," are the life-blood of the digital underground. Boards were also central to law enforcement's tactics and strategy in the Hacker Crackdown. A "bulletin board system" can be formally defined as a computer which serves as an information and message- passing center for users dialing-up over the phone-lines through the use of modems. A "modem," or modulator- demodulator, is a device which translates the digital impulses of computers into audible analog telephone signals, and vice versa. Modems connect computers to phones and thus to each other. Large-scale mainframe computers have been connected since the 1960s, but PERSONAL computers, run by individuals out of their homes, were first networked in the late 1970s. The "board" created by Ward Christensen and Randy Suess in February 1978, in Chicago, Illinois, is generally regarded as the first personal-computer bulletin board system worthy of the name. Boards run on many different machines, employing many different kinds of software. Early boards were crude and buggy, and their managers, known as "system operators" or "sysops," were hard-working technical experts who wrote their own software. But like most everything else in the world of electronics, boards became faster, cheaper, better-designed, and generally far more sophisticated throughout the 1980s. They also moved swiftly out of the hands of pioneers and into those of the general public. By 1985 there were something in the neighborhood of 4,000 boards in America. By 1990 it was calculated, vaguely, that there were about 30,000 boards in the US, with uncounted thousands overseas. Computer bulletin boards are unregulated enterprises. Running a board is a rough-and-ready, catch-as-catch-can proposition. Basically, anybody with a computer, modem, software and a phone-line can start a board. With second-hand equipment and public-domain free software, the price of a board might be quite small-- less than it would take to publish a magazine or even a decent pamphlet. Entrepreneurs eagerly sell bulletin-board software, and will coach nontechnical amateur sysops in its use. Boards are not "presses." They are not magazines, or libraries, or phones, or CB radios, or traditional cork bulletin boards down at the local laundry, though they have some passing resemblance to those earlier media. Boards are a new medium--they may even be a LARGE NUMBER of new media. Consider these unique characteristics: boards are cheap, yet they can have a national, even global reach. Boards can be contacted from anywhere in the global telephone network, at NO COST to the person running the board-- the caller pays the phone bill, and if the caller is local, the call is free. Boards do not involve an editorial elite addressing a mass audience. The "sysop" of a board is not an exclusive publisher or writer--he is managing an electronic salon, where individuals can address the general public, play the part of the general public, and also exchange private mail with other individuals. And the "conversation" on boards, though fluid, rapid, and highly interactive, is not spoken, but written. It is also relatively anonymous, sometimes completely so. And because boards are cheap and ubiquitous, regulations and licensing requirements would likely be practically unenforceable. It would almost be easier to "regulate," "inspect," and "license" the content of private mail--probably more so, since the mail system is operated by the federal government. Boards are run by individuals, independently, entirely at their own whim. For the sysop, the cost of operation is not the primary limiting factor. Once the investment in a computer and modem has been made, the only steady cost is the charge for maintaining a phone line (or several phone lines). The primary limits for sysops are time and energy. Boards require upkeep. New users are generally "validated"-- they must be issued individual passwords, and called at home by voice-phone, so that their identity can be verified. Obnoxious users, who exist in plenty, must be chided or purged. Proliferating messages must be deleted when they grow old, so that the capacity of the system is not overwhelmed. And software programs (if such things are kept on the board) must be examined for possible computer viruses. If there is a financial charge to use the board (increasingly common, especially in larger and fancier systems) then accounts must be kept, and users must be billed. And if the board crashes--a very common occurrence--then repairs must be made. Boards can be distinguished by the amount of effort spent in regulating them. First, we have the completely open board, whose sysop is off chugging brews and watching re-runs while his users generally degenerate over time into peevish anarchy and eventual silence. Second comes the supervised board, where the sysop breaks in every once in a while to tidy up, calm brawls, issue announcements, and rid the community of dolts and troublemakers. Third is the heavily supervised board, which sternly urges adult and responsible behavior and swiftly edits any message considered offensive, impertinent, illegal or irrelevant. And last comes the completely edited "electronic publication," which is presented to a silent audience which is not allowed to respond directly in any way. Boards can also be grouped by their degree of anonymity. There is the completely anonymous board, where everyone uses pseudonyms--"handles"--and even the sysop is unaware of the user's true identity. The sysop himself is likely pseudonymous on a board of this type. Second, and rather more common, is the board where the sysop knows (or thinks he knows) the true names and addresses of all users, but the users don't know one another's names and may not know his. Third is the board where everyone has to use real names, and roleplaying and pseudonymous posturing are forbidden. Boards can be grouped by their immediacy. "Chat-lines" are boards linking several users together over several different phone-lines simultaneously, so that people exchange messages at the very moment that they type. (Many large boards feature "chat" capabilities along with other services.) Less immediate boards, perhaps with a single phoneline, store messages serially, one at a time. And some boards are only open for business in daylight hours or on weekends, which greatly slows response. A NETWORK of boards, such as "FidoNet," can carry electronic mail from board to board, continent to continent, across huge distances-- but at a relative snail's pace, so that a message can take several days to reach its target audience and elicit a reply. Boards can be grouped by their degree of community. Some boards emphasize the exchange of private, person-to-person electronic mail. Others emphasize public postings and may even purge people who "lurk," merely reading posts but refusing to openly participate. Some boards are intimate and neighborly. Others are frosty and highly technical. Some are little more than storage dumps for software, where users "download" and "upload" programs, but interact among themselves little if at all. Boards can be grouped by their ease of access. Some boards are entirely public. Others are private and restricted only to personal friends of the sysop. Some boards divide users by status. On these boards, some users, especially beginners, strangers or children, will be restricted to general topics, and perhaps forbidden to post. Favored users, though, are granted the ability to post as they please, and to stay "on-line" as long as they like, even to the disadvantage of other people trying to call in. High-status users can be given access to hidden areas in the board, such as off-color topics, private discussions, and/or valuable software. Favored users may even become "remote sysops" with the power to take remote control of the board through their own home computers. Quite often "remote sysops" end up doing all the work and taking formal control of the enterprise, despite the fact that it's physically located in someone else's house. Sometimes several "co-sysops" share power. And boards can also be grouped by size. Massive, nationwide commercial networks, such as CompuServe, Delphi, GEnie and Prodigy, are run on mainframe computers and are generally not considered "boards," though they share many of their characteristics, such as electronic mail, discussion topics, libraries of software, and persistent and growing problems with civil-liberties issues. Some private boards have as many as thirty phone-lines and quite sophisticated hardware. And then there are tiny boards. Boards vary in popularity. Some boards are huge and crowded, where users must claw their way in against a constant busy-signal. Others are huge and empty--there are few things sadder than a formerly flourishing board where no one posts any longer, and the dead conversations of vanished users lie about gathering digital dust. Some boards are tiny and intimate, their telephone numbers intentionally kept confidential so that only a small number can log on. And some boards are UNDERGROUND. Boards can be mysterious entities. The activities of their users can be hard to differentiate from conspiracy. Sometimes they ARE conspiracies. Boards have harbored, or have been accused of harboring, all manner of fringe groups, and have abetted, or been accused of abetting, every manner of frowned-upon, sleazy, radical, and criminal activity. There are Satanist boards. Nazi boards. Pornographic boards. Pedophile boards. Drug- dealing boards. Anarchist boards. Communist boards. Gay and Lesbian boards (these exist in great profusion, many of them quite lively with well-established histories). Religious cult boards. Evangelical boards. Witchcraft boards, hippie boards, punk boards, skateboarder boards. Boards for UFO believers. There may well be boards for serial killers, airline terrorists and professional assassins. There is simply no way to tell. Boards spring up, flourish, and disappear in large numbers, in most every corner of the developed world. Even apparently innocuous public boards can, and sometimes do, harbor secret areas known only to a few. And even on the vast, public, commercial services, private mail is very private--and quite possibly criminal. Boards cover most every topic imaginable and some that are hard to imagine. They cover a vast spectrum of social activity. However, all board users do have something in common: their possession of computers and phones. Naturally, computers and phones are primary topics of conversation on almost every board. And hackers and phone phreaks, those utter devotees of computers and phones, live by boards. They swarm by boards. They are bred by boards. By the late 1980s, phone-phreak groups and hacker groups, united by boards, had proliferated fantastically. As evidence, here is a list of hacker groups compiled by the editors of Phrack on August 8, 1988. The Administration. Advanced Telecommunications, Inc. ALIAS. American Tone Travelers. Anarchy Inc. Apple Mafia. The Association. Atlantic Pirates Guild. Bad Ass Mother Fuckers. Bellcore. Bell Shock Force. Black Bag. Camorra. C&M Productions. Catholics Anonymous. Chaos Computer Club. Chief Executive Officers. Circle Of Death. Circle Of Deneb. Club X. Coalition of Hi-Tech Pirates. Coast-To-Coast. Corrupt Computing. Cult Of The Dead Cow. Custom Retaliations. Damage Inc. D&B Communications. The Danger Gang. Dec Hunters. Digital Gang. DPAK. Eastern Alliance. The Elite Hackers Guild. Elite Phreakers and Hackers Club. The Elite Society Of America. EPG. Executives Of Crime. Extasyy Elite. Fargo 4A. Farmers Of Doom. The Federation. Feds R Us. First Class. Five O. Five Star. Force Hackers. The 414s. Hack-A-Trip. Hackers Of America. High Mountain Hackers. High Society. The Hitchhikers. IBM Syndicate. The Ice Pirates. Imperial Warlords. Inner Circle. Inner Circle II. Insanity Inc. International Computer Underground Bandits. Justice League of America. Kaos Inc. Knights Of Shadow. Knights Of The Round Table. League Of Adepts. Legion Of Doom. Legion Of Hackers. Lords Of Chaos. Lunatic Labs, Unlimited. Master Hackers. MAD! The Marauders. MD/PhD. Metal Communications, Inc. MetalliBashers, Inc. MBI. Metro Communications. Midwest Pirates Guild. NASA Elite. The NATO Association. Neon Knights. Nihilist Order. Order Of The Rose. OSS. Pacific Pirates Guild. Phantom Access Associates. PHido PHreaks. The Phirm. Phlash. PhoneLine Phantoms. Phone Phreakers Of America. Phortune 500. Phreak Hack Delinquents. Phreak Hack Destroyers. Phreakers, Hackers, And Laundromat Employees Gang (PHALSE Gang). Phreaks Against Geeks. Phreaks Against Phreaks Against Geeks. Phreaks and Hackers of America. Phreaks Anonymous World Wide. Project Genesis. The Punk Mafia. The Racketeers. Red Dawn Text Files. Roscoe Gang. SABRE. Secret Circle of Pirates. Secret Service. 707 Club. Shadow Brotherhood. Sharp Inc. 65C02 Elite. Spectral Force. Star League. Stowaways. Strata-Crackers. Team Hackers '86. Team Hackers '87. TeleComputist Newsletter Staff. Tribunal Of Knowledge. Triple Entente. Turn Over And Die Syndrome (TOADS). 300 Club. 1200 Club. 2300 Club. 2600 Club. 2601 Club. 2AF. The United Soft WareZ Force. United Technical Underground. Ware Brigade. The Warelords. WASP. Contemplating this list is an impressive, almost humbling business. As a cultural artifact, the thing approaches poetry. Underground groups--subcultures--can be distinguished from independent cultures by their habit of referring constantly to the parent society. Undergrounds by their nature constantly must maintain a membrane of differentiation. Funny/distinctive clothes and hair, specialized jargon, specialized ghettoized areas in cities, different hours of rising, working, sleeping. . . . The digital underground, which specializes in information, relies very heavily on language to distinguish itself. As can be seen from this list, they make heavy use of parody and mockery. It's revealing to see who they choose to mock. First, large corporations. We have the Phortune 500, The Chief Executive Officers, Bellcore, IBM Syndicate, SABRE (a computerized reservation service maintained by airlines). The common use of "Inc." is telling-- none of these groups are actual corporations, but take clear delight in mimicking them. Second, governments and police. NASA Elite, NATO Association. "Feds R Us" and "Secret Service" are fine bits of fleering boldness. OSS--the Office of Strategic Services was the forerunner of the CIA. Third, criminals. Using stigmatizing pejoratives as a perverse badge of honor is a time-honored tactic for subcultures: punks, gangs, delinquents, mafias, pirates, bandits, racketeers. Specialized orthography, especially the use of "ph" for "f" and "z" for the plural "s," are instant recognition symbols. So is the use of the numeral "0" for the letter "O" --computer-software orthography generally features a slash through the zero, making the distinction obvious. Some terms are poetically descriptive of computer intrusion: the Stowaways, the Hitchhikers, the PhoneLine Phantoms, Coast-to-Coast. Others are simple bravado and vainglorious puffery. (Note the insistent use of the terms "elite" and "master.") Some terms are blasphemous, some obscene, others merely cryptic-- anything to puzzle, offend, confuse, and keep the straights at bay. Many hacker groups further re-encrypt their names by the use of acronyms: United Technical Underground becomes UTU, Farmers of Doom become FoD, the United SoftWareZ Force becomes, at its own insistence, "TuSwF," and woe to the ignorant rodent who capitalizes the wrong letters. It should be further recognized that the members of these groups are themselves pseudonymous. If you did, in fact, run across the "PhoneLine Phantoms," you would find them to consist of "Carrier Culprit," "The Executioner," "Black Majik," "Egyptian Lover," "Solid State," and "Mr Icom." "Carrier Culprit" will likely be referred to by his friends as "CC," as in, "I got these dialups from CC of PLP." It's quite possible that this entire list refers to as few as a thousand people. It is not a complete list of underground groups--there has never been such a list, and there never will be. Groups rise, flourish, decline, share membership, maintain a cloud of wannabes and casual hangers-on. People pass in and out, are ostracized, get bored, are busted by police, or are cornered by telco security and presented with huge bills. Many "underground groups" are software pirates, "warez d00dz," who might break copy protection and pirate programs, but likely wouldn't dare to intrude on a computer-system. It is hard to estimate the true population of the digital underground. There is constant turnover. Most hackers start young, come and go, then drop out at age 22-- the age of college graduation. And a large majority of "hackers" access pirate boards, adopt a handle, swipe software and perhaps abuse a phone-code or two, while never actually joining the elite. Some professional informants, who make it their business to retail knowledge of the underground to paymasters in private corporate security, have estimated the hacker population at as high as fifty thousand. This is likely highly inflated, unless one counts every single teenage software pirate and petty phone-booth thief. My best guess is about 5,000 people. Of these, I would guess that as few as a hundred are truly "elite" --active computer intruders, skilled enough to penetrate sophisticated systems and truly to worry corporate security and law enforcement. Another interesting speculation is whether this group is growing or not. Young teenage hackers are often convinced that hackers exist in vast swarms and will soon dominate the cybernetic universe. Older and wiser veterans, perhaps as wizened as 24 or 25 years old, are convinced that the glory days are long gone, that the cops have the underground's number now, and that kids these days are dirt-stupid and just want to play Nintendo. My own assessment is that computer intrusion, as a non-profit act of intellectual exploration and mastery, is in slow decline, at least in the United States; but that electronic fraud, especially telecommunication crime, is growing by leaps and bounds. One might find a useful parallel to the digital underground in the drug underground. There was a time, now much-obscured by historical revisionism, when Bohemians freely shared joints at concerts, and hip, small-scale marijuana dealers might turn people on just for the sake of enjoying a long stoned conversation about the Doors and Allen Ginsberg. Now drugs are increasingly verboten, except in a high-stakes, highly-criminal world of highly addictive drugs. Over years of disenchantment and police harassment, a vaguely ideological, free-wheeling drug underground has relinquished the business of drug-dealing to a far more savage criminal hard-core. This is not a pleasant prospect to contemplate, but the analogy is fairly compelling. What does an underground board look like? What distinguishes it from a standard board? It isn't necessarily the conversation-- hackers often talk about common board topics, such as hardware, software, sex, science fiction, current events, politics, movies, personal gossip. Underground boards can best be distinguished by their files, or "philes," pre-composed texts which teach the techniques and ethos of the underground. These are prized reservoirs of forbidden knowledge. Some are anonymous, but most proudly bear the handle of the "hacker" who has created them, and his group affiliation, if he has one. Here is a partial table-of-contents of philes from an underground board, somewhere in the heart of middle America, circa 1991. The descriptions are mostly self-explanatory. BANKAMER.ZIP 5406 06-11-91 Hacking Bank America CHHACK.ZIP 4481 06-11-91 Chilton Hacking CITIBANK.ZIP 4118 06-11-91 Hacking Citibank CREDIMTC.ZIP 3241 06-11-91 Hacking Mtc Credit Company DIGEST.ZIP 5159 06-11-91 Hackers Digest HACK.ZIP 14031 06-11-91 How To Hack HACKBAS.ZIP 5073 06-11-91 Basics Of Hacking HACKDICT.ZIP 42774 06-11-91 Hackers Dictionary HACKER.ZIP 57938 06-11-91 Hacker Info HACKERME.ZIP 3148 06-11-91 Hackers Manual HACKHAND.ZIP 4814 06-11-91 Hackers Handbook HACKTHES.ZIP 48290 06-11-91 Hackers Thesis HACKVMS.ZIP 4696 06-11-91 Hacking Vms Systems MCDON.ZIP 3830 06-11-91 Hacking Macdonalds (Home Of The Archs) P500UNIX.ZIP 15525 06-11-91 Phortune 500 Guide To Unix RADHACK.ZIP 8411 06-11-91 Radio Hacking TAOTRASH.DOC 4096 12-25-89 Suggestions For Trashing TECHHACK.ZIP 5063 06-11-91 Technical Hacking The files above are do-it-yourself manuals about computer intrusion. The above is only a small section of a much larger library of hacking and phreaking techniques and history. We now move into a different and perhaps surprising area. +------------+ |Anarchy| +------------+ ANARC.ZIP 3641 06-11-91 Anarchy Files ANARCHST.ZIP 63703 06-11-91 Anarchist Book ANARCHY.ZIP 2076 06-11-91 Anarchy At Home ANARCHY3.ZIP 6982 06-11-91 Anarchy No 3 ANARCTOY.ZIP 2361 06-11-91 Anarchy Toys ANTIMODM.ZIP 2877 06-11-91 Anti-modem Weapons ATOM.ZIP 4494 06-11-91 How To Make An Atom Bomb BARBITUA.ZIP 3982 06-11-91 Barbiturate Formula BLCKPWDR.ZIP 2810 06-11-91 Black Powder Formulas BOMB.ZIP 3765 06-11-91 How To Make Bombs BOOM.ZIP 2036 06-11-91 Things That Go Boom CHLORINE.ZIP 1926 06-11-91 Chlorine Bomb COOKBOOK.ZIP 1500 06-11-91 Anarchy Cook Book DESTROY.ZIP 3947 06-11-91 Destroy Stuff DUSTBOMB.ZIP 2576 06-11-91 Dust Bomb ELECTERR.ZIP 3230 06-11-91 Electronic Terror EXPLOS1.ZIP 2598 06-11-91 Explosives 1 EXPLOSIV.ZIP 18051 06-11-91 More Explosives EZSTEAL.ZIP 4521 06-11-91 Ez-stealing FLAME.ZIP 2240 06-11-91 Flame Thrower FLASHLT.ZIP 2533 06-11-91 Flashlight Bomb FMBUG.ZIP 2906 06-11-91 How To Make An Fm Bug OMEEXPL.ZIP 2139 06-11-91 Home Explosives HOW2BRK.ZIP 3332 06-11-91 How To Break In LETTER.ZIP 2990 06-11-91 Letter Bomb LOCK.ZIP 2199 06-11-91 How To Pick Locks MRSHIN.ZIP 3991 06-11-91 Briefcase Locks NAPALM.ZIP 3563 06-11-91 Napalm At Home NITRO.ZIP 3158 06-11-91 Fun With Nitro PARAMIL.ZIP 2962 06-11-91 Paramilitary Info PICKING.ZIP 3398 06-11-91 Picking Locks PIPEBOMB.ZIP 2137 06-11-91 Pipe Bomb POTASS.ZIP 3987 06-11-91 Formulas With Potassium PRANK.TXT 11074 08-03-90 More Pranks To Pull On Idiots! REVENGE.ZIP 4447 06-11-91 Revenge Tactics ROCKET.ZIP 2590 06-11-91 Rockets For Fun SMUGGLE.ZIP 3385 06-11-91 How To Smuggle HOLY COW! The damned thing is full of stuff about bombs! What are we to make of this? First, it should be acknowledged that spreading knowledge about demolitions to teenagers is a highly and deliberately antisocial act. It is not, however, illegal. Second, it should be recognized that most of these philes were in fact WRITTEN by teenagers. Most adult American males who can remember their teenage years will recognize that the notion of building a flamethrower in your garage is an incredibly neat-o idea. ACTUALLY, building a flamethrower in your garage, however, is fraught with discouraging difficulty. Stuffing gunpowder into a booby-trapped flashlight, so as to blow the arm off your high-school vice-principal, can be a thing of dark beauty to contemplate. Actually committing assault by explosives will earn you the sustained attention of the federal Bureau of Alcohol, Tobacco and Firearms. Some people, however, will actually try these plans. A determinedly murderous American teenager can probably buy or steal a handgun far more easily than he can brew fake "napalm" in the kitchen sink. Nevertheless, if temptation is spread before people, a certain number will succumb, and a small minority will actually attempt these stunts. A large minority of that small minority will either fail or, quite likely, maim themselves, since these "philes" have not been checked for accuracy, are not the product of professional experience, and are often highly fanciful. But the gloating menace of these philes is not to be entirely dismissed. Hackers may not be "serious" about bombing; if they were, we would hear far more about exploding flashlights, homemade bazookas, and gym teachers poisoned by chlorine and potassium. However, hackers are VERY serious about forbidden knowledge. They are possessed not merely by curiosity, but by a positive LUST TO KNOW. The desire to know what others don't is scarcely new. But the INTENSITY of this desire, as manifested by these young technophilic denizens of the Information Age, may in fact BE new, and may represent some basic shift in social values-- a harbinger of what the world may come to, as society lays more and more value on the possession, assimilation and retailing of INFORMATION as a basic commodity of daily life. There have always been young men with obsessive interests in these topics. Never before, however, have they been able to network so extensively and easily, and to propagandize their interests with impunity to random passers-by. High-school teachers will recognize that there's always one in a crowd, but when the one in a crowd escapes control by jumping into the phone-lines, and becomes a hundred such kids all together on a board, then trouble is brewing visibly. The urge of authority to DO SOMETHING, even something drastic, is hard to resist. And in 1990, authority did something. In fact authority did a great deal. # The process by which boards create hackers goes something like this. A youngster becomes interested in computers-- usually, computer games. He hears from friends that "bulletin boards" exist where games can be obtained for free. (Many computer games are "freeware," not copyrighted-- invented simply for the love of it and given away to the public; some of these games are quite good.) He bugs his parents for a modem, or quite often, uses his parents' modem. The world of boards suddenly opens up. Computer games can be quite expensive, real budget-breakers for a kid, but pirated games, stripped of copy protection, are cheap or free. They are also illegal, but it is very rare, almost unheard of, for a small-scale software pirate to be prosecuted. Once "cracked" of its copy protection, the program, being digital data, becomes infinitely reproducible. Even the instructions to the game, any manuals that accompany it, can be reproduced as text files, or photocopied from legitimate sets. Other users on boards can give many useful hints in game-playing tactics. And a youngster with an infinite supply of free computer games can certainly cut quite a swath among his modem-less friends. And boards are pseudonymous. No one need know that you're fourteen years old--with a little practice at subterfuge, you can talk to adults about adult things, and be accepted and taken seriously! You can even pretend to be a girl, or an old man, or anybody you can imagine. If you find this kind of deception gratifying, there is ample opportunity to hone your ability on boards. But local boards can grow stale. And almost every board maintains a list of phone-numbers to other boards, some in distant, tempting, exotic locales. Who knows what they're up to, in Oregon or Alaska or Florida or California? It's very easy to find out--just order the modem to call through its software--nothing to this, just typing on a keyboard, the same thing you would do for most any computer game. The machine reacts swiftly and in a few seconds you are talking to a bunch of interesting people on another seaboard. And yet the BILLS for this trivial action can be staggering! Just by going tippety-tap with your fingers, you may have saddled your parents with four hundred bucks in long-distance charges, and gotten chewed out but good. That hardly seems fair. How horrifying to have made friends in another state and to be deprived of their company--and their software-- just because telephone companies demand absurd amounts of money! How painful, to be restricted to boards in one's own AREA CODE-- what the heck is an "area code" anyway, and what makes it so special? A few grumbles, complaints, and innocent questions of this sort will often elicit a sympathetic reply from another board user-- someone with some stolen codes to hand. You dither a while, knowing this isn't quite right, then you make up your mind to try them anyhow--AND THEY WORK! Suddenly you're doing something even your parents can't do. Six months ago you were just some kid--now, you're the Crimson Flash of Area Code 512! You're bad--you're nationwide! Maybe you'll stop at a few abused codes. Maybe you'll decide that boards aren't all that interesting after all, that it's wrong, not worth the risk --but maybe you won't. The next step is to pick up your own repeat-dialling program-- to learn to generate your own stolen codes. (This was dead easy five years ago, much harder to get away with nowadays, but not yet impossible.) And these dialling programs are not complex or intimidating-- some are as small as twenty lines of software. Now, you too can share codes. You can trade codes to learn other techniques. If you're smart enough to catch on, and obsessive enough to want to bother, and ruthless enough to start seriously bending rules, then you'll get better, fast. You start to develop a rep. You move up to a heavier class of board--a board with a bad attitude, the kind of board that naive dopes like your classmates and your former self have never even heard of! You pick up the jargon of phreaking and hacking from the board. You read a few of those anarchy philes-- and man, you never realized you could be a real OUTLAW without ever leaving your bedroom. You still play other computer games, but now you have a new and bigger game. This one will bring you a different kind of status than destroying even eight zillion lousy space invaders. Hacking is perceived by hackers as a "game." This is not an entirely unreasonable or sociopathic perception. You can win or lose at hacking, succeed or fail, but it never feels "real." It's not simply that imaginative youngsters sometimes have a hard time telling "make-believe" from "real life." Cyberspace is NOT REAL! "Real" things are physical objects like trees and shoes and cars. Hacking takes place on a screen. Words aren't physical, numbers (even telephone numbers and credit card numbers) aren't physical. Sticks and stones may break my bones, but data will never hurt me. Computers SIMULATE reality, like computer games that simulate tank battles or dogfights or spaceships. Simulations are just make-believe, and the stuff in computers is NOT REAL. Consider this: if "hacking" is supposed to be so serious and real-life and dangerous, then how come NINE-YEAR-OLD KIDS have computers and modems? You wouldn't give a nine year old his own car, or his own rifle, or his own chainsaw--those things are "real." People underground are perfectly aware that the "game" is frowned upon by the powers that be. Word gets around about busts in the underground. Publicizing busts is one of the primary functions of pirate boards, but they also promulgate an attitude about them, and their own idiosyncratic ideas of justice. The users of underground boards won't complain if some guy is busted for crashing systems, spreading viruses, or stealing money by wire-fraud. They may shake their heads with a sneaky grin, but they won't openly defend these practices. But when a kid is charged with some theoretical amount of theft: $233,846.14, for instance, because he sneaked into a computer and copied something, and kept it in his house on a floppy disk-- this is regarded as a sign of near-insanity from prosecutors, a sign that they've drastically mistaken the immaterial game of computing for their real and boring everyday world of fatcat corporate money. It's as if big companies and their suck-up lawyers think that computing belongs to them, and they can retail it with price stickers, as if it were boxes of laundry soap! But pricing "information" is like trying to price air or price dreams. Well, anybody on a pirate board knows that computing can be, and ought to be, FREE. Pirate boards are little independent worlds in cyberspace, and they don't belong to anybody but the underground. Underground boards aren't "brought to you by Procter & Gamble." To log on to an underground board can mean to experience liberation, to enter a world where, for once, money isn't everything and adults don't have all the answers. Let's sample another vivid hacker manifesto. Here are some excerpts from "The Conscience of a Hacker," by "The Mentor," from Phrack Volume One, Issue 7, Phile 3. "I made a discovery today. I found a computer. Wait a second, this is cool. It does what I want it to. If it makes a mistake, it's because I screwed it up. Not because it doesn't like me. (. . .) "And then it happened. . .a door opened to a world. . . rushing through the phone line like heroin through an addict's veins, an electronic pulse is sent out, a refuge from day-to-day incompetencies is sought. . . a board is found. `This is it. . .this is where I belong. . .' "I know everyone here. . .even if I've never met them, never talked to them, may never hear from them again. . . I know you all. . . (. . .) "This is our world now. . .the world of the electron and the switch, the beauty of the baud. We make use of a service already existing without paying for what could be dirt-cheap if it wasn't run by profiteering gluttons, and you call us criminals. We explore. . .and you call us criminals. We seek after knowledge. . .and you call us criminals. We exist without skin color, without nationality, without religious bias. . .and you call us criminals. You build atomic bombs, you wage wars, you murder, cheat and lie to us and try to make us believe that it's for our own good, yet we're the criminals. "Yes, I am a criminal. My crime is that of curiosity. My crime is that of judging people by what they say and think, not what they look like. My crime is that of outsmarting you, something that you will never forgive me for." # There have been underground boards almost as long as there have been boards. One of the first was 8BBS, which became a stronghold of the West Coast phone-phreak elite. After going on-line in March 1980, 8BBS sponsored "Susan Thunder," and "Tuc," and, most notoriously, "the Condor." "The Condor" bore the singular distinction of becoming the most vilified American phreak and hacker ever. Angry underground associates, fed up with Condor's peevish behavior, turned him in to police, along with a heaping double-helping of outrageous hacker legendry. As a result, Condor was kept in solitary confinement for seven months, for fear that he might start World War Three by triggering missile silos from the prison payphone. (Having served his time, Condor is now walking around loose; WWIII has thus far conspicuously failed to occur.) The sysop of 8BBS was an ardent free-speech enthusiast who simply felt that ANY attempt to restrict the expression of his users was unconstitutional and immoral. Swarms of the technically curious entered 8BBS and emerged as phreaks and hackers, until, in 1982, a friendly 8BBS alumnus passed the sysop a new modem which had been purchased by credit-card fraud. Police took this opportunity to seize the entire board and remove what they considered an attractive nuisance. Plovernet was a powerful East Coast pirate board that operated in both New York and Florida. Owned and operated by teenage hacker "Quasi Moto," Plovernet attracted five hundred eager users in 1983. "Emmanuel Goldstein" was one-time co-sysop of Plovernet, along with "Lex Luthor," founder of the "Legion of Doom" group. Plovernet bore the signal honor of being the original home of the "Legion of Doom," about which the reader will be hearing a great deal, soon. "Pirate-80," or "P-80," run by a sysop known as "Scan-Man," got into the game very early in Charleston, and continued steadily for years. P-80 flourished so flagrantly that even its most hardened users became nervous, and some slanderously speculated that "Scan Man" must have ties to corporate security, a charge he vigorously denied. "414 Private" was the home board for the first GROUP to attract conspicuous trouble, the teenage "414 Gang," whose intrusions into Sloan-Kettering Cancer Center and Los Alamos military computers were to be a nine-days-wonder in 1982. At about this time, the first software piracy boards began to open up, trading cracked games for the Atari 800 and the Commodore C64. Naturally these boards were heavily frequented by teenagers. And with the 1983 release of the hacker-thriller movie War Games, the scene exploded. It seemed that every kid in America had demanded and gotten a modem for Christmas. Most of these dabbler wannabes put their modems in the attic after a few weeks, and most of the remainder minded their P's and Q's and stayed well out of hot water. But some stubborn and talented diehards had this hacker kid in War Games figured for a happening dude. They simply could not rest until they had contacted the underground-- or, failing that, created their own. In the mid-80s, underground boards sprang up like digital fungi. ShadowSpawn Elite. Sherwood Forest I, II, and III. Digital Logic Data Service in Florida, sysoped by no less a man than "Digital Logic" himself; Lex Luthor of the Legion of Doom was prominent on this board, since it was in his area code. Lex's own board, "Legion of Doom," started in 1984. The Neon Knights ran a network of Apple- hacker boards: Neon Knights North, South, East and West. Free World II was run by "Major Havoc." Lunatic Labs is still in operation as of this writing. Dr. Ripco in Chicago, an anything-goes anarchist board with an extensive and raucous history, was seized by Secret Service agents in 1990 on Sundevil day, but up again almost immediately, with new machines and scarcely diminished vigor. The St. Louis scene was not to rank with major centers of American hacking such as New York and L.A. But St. Louis did rejoice in possession of "Knight Lightning" and "Taran King," two of the foremost JOURNALISTS native to the underground. Missouri boards like Metal Shop, Metal Shop Private, Metal Shop Brewery, may not have been the heaviest boards around in terms of illicit expertise. But they became boards where hackers could exchange social gossip and try to figure out what the heck was going on nationally--and internationally. Gossip from Metal Shop was put into the form of news files, then assembled into a general electronic publication, Phrack, a portmanteau title coined from "phreak" and "hack." The Phrack editors were as obsessively curious about other hackers as hackers were about machines. Phrack, being free of charge and lively reading, began to circulate throughout the underground. As Taran King and Knight Lightning left high school for college, Phrack began to appear on mainframe machines linked to BITNET, and, through BITNET to the "Internet," that loose but extremely potent not-for-profit network where academic, governmental and corporate machines trade data through the UNIX TCP/IP protocol. (The "Internet Worm" of November 2-3,1988, created by Cornell grad student Robert Morris, was to be the largest and best-publicized computer-intrusion scandal to date. Morris claimed that his ingenious "worm" program was meant to harmlessly explore the Internet, but due to bad programming, the Worm replicated out of control and crashed some six thousand Internet computers. Smaller-scale and less ambitious Internet hacking was a standard for the underground elite.) Most any underground board not hopelessly lame and out-of-it would feature a complete run of Phrack--and, possibly, the lesser-known standards of the underground: the Legion of Doom Technical Journal, the obscene and raucous Cult of the Dead Cow files, P/HUN magazine, Pirate, the Syndicate Reports, and perhaps the highly anarcho-political Activist Times Incorporated. Possession of Phrack on one's board was prima facie evidence of a bad attitude. Phrack was seemingly everywhere, aiding, abetting, and spreading the underground ethos. And this did not escape the attention of corporate security or the police. We now come to the touchy subject of police and boards. Police, do, in fact, own boards. In 1989, there were police-sponsored boards in California, Colorado, Florida, Georgia, Idaho, Michigan, Missouri, Texas, and Virginia: boards such as "Crime Bytes," "Crimestoppers," "All Points" and "Bullet-N-Board." Police officers, as private computer enthusiasts, ran their own boards in Arizona, California, Colorado, Connecticut, Florida, Missouri, Maryland, New Mexico, North Carolina, Ohio, Tennessee and Texas. Police boards have often proved helpful in community relations. Sometimes crimes are reported on police boards. Sometimes crimes are COMMITTED on police boards. This has sometimes happened by accident, as naive hackers blunder onto police boards and blithely begin offering telephone codes. Far more often, however, it occurs through the now almost-traditional use of "sting boards." The first police sting-boards were established in 1985: "Underground Tunnel" in Austin, Texas, whose sysop Sgt. Robert Ansley called himself "Pluto"--"The Phone Company" in Phoenix, Arizona, run by Ken MacLeod of the Maricopa County Sheriff's office--and Sgt. Dan Pasquale's board in Fremont, California. Sysops posed as hackers, and swiftly garnered coteries of ardent users, who posted codes and loaded pirate software with abandon, and came to a sticky end. Sting boards, like other boards, are cheap to operate, very cheap by the standards of undercover police operations. Once accepted by the local underground, sysops will likely be invited into other pirate boards, where they can compile more dossiers. And when the sting is announced and the worst offenders arrested, the publicity is generally gratifying. The resultant paranoia in the underground--perhaps more justly described as a "deterrence effect"-- tends to quell local lawbreaking for quite a while. Obviously police do not have to beat the underbrush for hackers. On the contrary, they can go trolling for them. Those caught can be grilled. Some become useful informants. They can lead the way to pirate boards all across the country. And boards all across the country showed the sticky fingerprints of Phrack, and of that loudest and most flagrant of all underground groups, the "Legion of Doom." The term "Legion of Doom" came from comic books. The Legion of Doom, a conspiracy of costumed super- villains headed by the chrome-domed criminal ultra- mastermind Lex Luthor, gave Superman a lot of four-color graphic trouble for a number of decades. Of course, Superman, that exemplar of Truth, Justice, and the American Way, always won in the long run. This didn't matter to the hacker Doomsters-- "Legion of Doom" was not some thunderous and evil Satanic reference, it was not meant to be taken seriously. "Legion of Doom" came from funny-books and was supposed to be funny. "Legion of Doom" did have a good mouthfilling ring to it, though. It sounded really cool. Other groups, such as the "Farmers of Doom," closely allied to LoD, recognized this grandiloquent quality, and made fun of it. There was even a hacker group called "Justice League of America," named after Superman's club of true-blue crimefighting superheros. But they didn't last; the Legion did. The original Legion of Doom, hanging out on Quasi Moto's Plovernet board, were phone phreaks. They weren't much into computers. "Lex Luthor" himself (who was under eighteen when he formed the Legion) was a COSMOS expert, COSMOS being the "Central System for Mainframe Operations," a telco internal computer network. Lex would eventually become quite a dab hand at breaking into IBM mainframes, but although everyone liked Lex and admired his attitude, he was not considered a truly accomplished computer intruder. Nor was he the "mastermind" of the Legion of Doom--LoD were never big on formal leadership. As a regular on Plovernet and sysop of his "Legion of Doom BBS," Lex was the Legion's cheerleader and recruiting officer. Legion of Doom began on the ruins of an earlier phreak group, The Knights of Shadow. Later, LoD was to subsume the personnel of the hacker group "Tribunal of Knowledge." People came and went constantly in LoD; groups split up or formed offshoots. Early on, the LoD phreaks befriended a few computer-intrusion enthusiasts, who became the associated "Legion of Hackers." Then the two groups conflated into the "Legion of Doom/Hackers," or LoD/H. When the original "hacker" wing, Messrs. "Compu-Phreak" and "Phucked Agent 04," found other matters to occupy their time, the extra "/H" slowly atrophied out of the name; but by this time the phreak wing, Messrs. Lex Luthor, "Blue Archer," "Gary Seven," "Kerrang Khan," "Master of Impact," "Silver Spy," "The Marauder," and "The Videosmith," had picked up a plethora of intrusion expertise and had become a force to be reckoned with. LoD members seemed to have an instinctive understanding that the way to real power in the underground lay through covert publicity. LoD were flagrant. Not only was it one of the earliest groups, but the members took pains to widely distribute their illicit knowledge. Some LoD members, like "The Mentor," were close to evangelical about it. Legion of Doom Technical Journal began to show up on boards throughout the underground. LoD Technical Journal was named in cruel parody of the ancient and honored AT&T Technical Journal. The material in these two publications was quite similar-- much of it, adopted from public journals and discussions in the telco community. And yet, the predatory attitude of LoD made even its most innocuous data seem deeply sinister; an outrage; a clear and present danger. To see why this should be, let's consider the following (invented) paragraphs, as a kind of thought experiment. (A) "W. Fred Brown, AT&T Vice President for Advanced Technical Development, testified May 8 at a Washington hearing of the National Telecommunications and Information Administration (NTIA), regarding Bellcore's GARDEN project. GARDEN (Generalized Automatic Remote Distributed Electronic Network) is a telephone-switch programming tool that makes it possible to develop new telecom services, including hold-on-hold and customized message transfers, from any keypad terminal, within seconds. The GARDEN prototype combines centrex lines with a minicomputer using UNIX operating system software." (B) "Crimson Flash 512 of the Centrex Mobsters reports: D00dz, you wouldn't believe this GARDEN bullshit Bellcore's just come up with! Now you don't even need a lousy Commodore to reprogram a switch--just log on to GARDEN as a technician, and you can reprogram switches right off the keypad in any public phone booth! You can give yourself hold-on-hold and customized message transfers, and best of all, the thing is run off (notoriously insecure) centrex lines using--get this--standard UNIX software! Ha ha ha ha!" Message (A), couched in typical techno-bureaucratese, appears tedious and almost unreadable. (A) scarcely seems threatening or menacing. Message (B), on the other hand, is a dreadful thing, prima facie evidence of a dire conspiracy, definitely not the kind of thing you want your teenager reading. The INFORMATION, however, is identical. It is PUBLIC information, presented before the federal government in an open hearing. It is not "secret." It is not "proprietary." It is not even "confidential." On the contrary, the development of advanced software systems is a matter of great public pride to Bellcore. However, when Bellcore publicly announces a project of this kind, it expects a certain attitude from the public--something along the lines of GOSH WOW, YOU GUYS ARE GREAT, KEEP THAT UP, WHATEVER IT IS-- certainly not cruel mimickry, one-upmanship and outrageous speculations about possible security holes. Now put yourself in the place of a policeman confronted by an outraged parent, or telco official, with a copy of Version (B). This well-meaning citizen, to his horror, has discovered a local bulletin-board carrying outrageous stuff like (B), which his son is examining with a deep and unhealthy interest. If (B) were printed in a book or magazine, you, as an American law enforcement officer, would know that it would take a hell of a lot of trouble to do anything about it; but it doesn't take technical genius to recognize that if there's a computer in your area harboring stuff like (B), there's going to be trouble. In fact, if you ask around, any computer-literate cop will tell you straight out that boards with stuff like (B) are the SOURCE of trouble. And the WORST source of trouble on boards are the ringleaders inventing and spreading stuff like (B). If it weren't for these jokers, there wouldn't BE any trouble. And Legion of Doom were on boards like nobody else. Plovernet. The Legion of Doom Board. The Farmers of Doom Board. Metal Shop. OSUNY. Blottoland. Private Sector. Atlantis. Digital Logic. Hell Phrozen Over. LoD members also ran their own boards. "Silver Spy" started his own board, "Catch-22," considered one of the heaviest around. So did "Mentor," with his "Phoenix Project." When they didn't run boards themselves, they showed up on other people's boards, to brag, boast, and strut. And where they themselves didn't go, their philes went, carrying evil knowledge and an even more evil attitude. As early as 1986, the police were under the vague impression that EVERYONE in the underground was Legion of Doom. LoD was never that large--considerably smaller than either "Metal Communications" or "The Administration," for instance-- but LoD got tremendous press. Especially in Phrack, which at times read like an LoD fan magazine; and Phrack was everywhere, especially in the offices of telco security. You couldn't GET busted as a phone phreak, a hacker, or even a lousy codes kid or warez dood, without the cops asking if you were LoD. This was a difficult charge to deny, as LoD never distributed membership badges or laminated ID cards. If they had, they would likely have died out quickly, for turnover in their membership was considerable. LoD was less a high-tech street-gang than an ongoing state-of-mind. LoD was the Gang That Refused to Die. By 1990, LoD had RULED for ten years, and it seemed WEIRD to police that they were continually busting people who were only sixteen years old. All these teenage small-timers were pleading the tiresome hacker litany of "just curious, no criminal intent." Somewhere at the center of this conspiracy there had to be some serious adult masterminds, not this seemingly endless supply of myopic suburban white kids with high SATs and funny haircuts. There was no question that most any American hacker arrested would "know" LoD. They knew the handles of contributors to LoD Tech Journal, and were likely to have learned their craft through LoD boards and LoD activism. But they'd never met anyone from LoD. Even some of the rotating cadre who were actually and formally "in LoD" knew one another only by board-mail and pseudonyms. This was a highly unconventional profile for a criminal conspiracy. Computer networking, and the rapid evolution of the digital underground, made the situation very diffuse and confusing. Furthermore, a big reputation in the digital underground did not coincide with one's willingness to commit "crimes." Instead, reputation was based on cleverness and technical mastery. As a result, it often seemed that the HEAVIER the hackers were, the LESS likely they were to have committed any kind of common, easily prosecutable crime. There were some hackers who could really steal. And there were hackers who could really hack. But the two groups didn't seem to overlap much, if at all. For instance, most people in the underground looked up to "Emmanuel Goldstein" of 2600 as a hacker demigod. But Goldstein's publishing activities were entirely legal-- Goldstein just printed dodgy stuff and talked about politics, he didn't even hack. When you came right down to it, Goldstein spent half his time complaining that computer security WASN'T STRONG ENOUGH and ought to be drastically improved across the board! Truly heavy-duty hackers, those with serious technical skills who had earned the respect of the underground, never stole money or abused credit cards. Sometimes they might abuse phone-codes-- but often, they seemed to get all the free phone-time they wanted without leaving a trace of any kind. The best hackers, the most powerful and technically accomplished, were not professional fraudsters. They raided computers habitually, but wouldn't alter anything, or damage anything. They didn't even steal computer equipment--most had day-jobs messing with hardware, and could get all the cheap secondhand equipment they wanted. The hottest hackers, unlike the teenage wannabes, weren't snobs about fancy or expensive hardware. Their machines tended to be raw second-hand digital hot-rods full of custom add-ons that they'd cobbled together out of chickenwire, memory chips and spit. Some were adults, computer software writers and consultants by trade, and making quite good livings at it. Some of them ACTUALLY WORKED FOR THE PHONE COMPANY--and for those, the "hackers" actually found under the skirts of Ma Bell, there would be little mercy in 1990. It has long been an article of faith in the underground that the "best" hackers never get caught. They're far too smart, supposedly. They never get caught because they never boast, brag, or strut. These demigods may read underground boards (with a condescending smile), but they never say anything there. The "best" hackers, according to legend, are adult computer professionals, such as mainframe system administrators, who already know the ins and outs of their particular brand of security. Even the "best" hacker can't break in to just any computer at random: the knowledge of security holes is too specialized, varying widely with different software and hardware. But if people are employed to run, say, a UNIX mainframe or a VAX/VMS machine, then they tend to learn security from the inside out. Armed with this knowledge, they can look into most anybody else's UNIX or VMS without much trouble or risk, if they want to. And, according to hacker legend, of course they want to, so of course they do. They just don't make a big deal of what they've done. So nobody ever finds out. It is also an article of faith in the underground that professional telco people "phreak" like crazed weasels. OF COURSE they spy on Madonna's phone calls--I mean, WOULDN'T YOU? Of course they give themselves free long- distance--why the hell should THEY pay, they're running the whole shebang! It has, as a third matter, long been an article of faith that any hacker caught can escape serious punishment if he confesses HOW HE DID IT. Hackers seem to believe that governmental agencies and large corporations are blundering about in cyberspace like eyeless jellyfish or cave salamanders. They feel that these large but pathetically stupid organizations will proffer up genuine gratitude, and perhaps even a security post and a big salary, to the hot-shot intruder who will deign to reveal to them the supreme genius of his modus operandi. In the case of longtime LoD member "Control-C," this actually happened, more or less. Control-C had led Michigan Bell a merry chase, and when captured in 1987, he turned out to be a bright and apparently physically harmless young fanatic, fascinated by phones. There was no chance in hell that Control-C would actually repay the enormous and largely theoretical sums in long-distance service that he had accumulated from Michigan Bell. He could always be indicted for fraud or computer-intrusion, but there seemed little real point in this--he hadn't physically damaged any computer. He'd just plead guilty, and he'd likely get the usual slap-on-the-wrist, and in the meantime it would be a big hassle for Michigan Bell just to bring up the case. But if kept on the payroll, he might at least keep his fellow hackers at bay. There were uses for him. For instance, a contrite Control-C was featured on Michigan Bell internal posters, sternly warning employees to shred their trash. He'd always gotten most of his best inside info from "trashing"--raiding telco dumpsters, for useful data indiscreetly thrown away. He signed these posters, too. Control-C had become something like a Michigan Bell mascot. And in fact, Control-C DID keep other hackers at bay. Little hackers were quite scared of Control-C and his heavy-duty Legion of Doom friends. And big hackers WERE his friends and didn't want to screw up his cushy situation. No matter what one might say of LoD, they did stick together. When "Wasp," an apparently genuinely malicious New York hacker, began crashing Bellcore machines, Control-C received swift volunteer help from "the Mentor" and the Georgia LoD wing made up of "The Prophet," "Urvile," and "Leftist." Using Mentor's Phoenix Project board to coordinate, the Doomsters helped telco security to trap Wasp, by luring him into a machine with a tap and line-trace installed. Wasp lost. LoD won! And my, did they brag. Urvile, Prophet and Leftist were well-qualified for this activity, probably more so even than the quite accomplished Control-C. The Georgia boys knew all about phone switching-stations. Though relative johnny-come-latelies in the Legion of Doom, they were considered some of LoD's heaviest guys, into the hairiest systems around. They had the good fortune to live in or near Atlanta, home of the sleepy and apparently tolerant BellSouth RBOC. As RBOC security went, BellSouth were "cake." US West (of Arizona, the Rockies and the Pacific Northwest) were tough and aggressive, probably the heaviest RBOC around. Pacific Bell, California's PacBell, were sleek, high-tech, and longtime veterans of the LA phone-phreak wars. NYNEX had the misfortune to run the New York City area, and were warily prepared for most anything. Even Michigan Bell, a division of the Ameritech RBOC, at least had the elementary sense to hire their own hacker as a useful scarecrow. But BellSouth, even though their corporate P.R. proclaimed them to have "Everything You Expect From a Leader," were pathetic. When rumor about LoD's mastery of Georgia's switching network got around to BellSouth through Bellcore and telco security scuttlebutt, they at first refused to believe it. If you paid serious attention to every rumor out and about these hacker kids, you would hear all kinds of wacko saucer-nut nonsense: that the National Security Agency monitored all American phone calls, that the CIA and DEA tracked traffic on bulletin-boards with word-analysis programs, that the Condor could start World War III from a payphone. If there were hackers into BellSouth switching-stations, then how come nothing had happened? Nothing had been hurt. BellSouth's machines weren't crashing. BellSouth wasn't suffering especially badly from fraud. BellSouth's customers weren't complaining. BellSouth was headquartered in Atlanta, ambitious metropolis of the new high-tech Sunbelt; and BellSouth was upgrading its network by leaps and bounds, digitizing the works left right and center. They could hardly be considered sluggish or naive. BellSouth's technical expertise was second to none, thank you kindly. But then came the Florida business. On June 13, 1989, callers to the Palm Beach County Probation Department, in Delray Beach, Florida, found themselves involved in a remarkable discussion with a phone-sex worker named "Tina" in New York State. Somehow, ANY call to this probation office near Miami was instantly and magically transported across state lines, at no extra charge to the user, to a pornographic phone-sex hotline hundreds of miles away! This practical joke may seem utterly hilarious at first hearing, and indeed there was a good deal of chuckling about it in phone phreak circles, including the Autumn 1989 issue of 2600. But for Southern Bell (the division of the BellSouth RBOC supplying local service for Florida, Georgia, North Carolina and South Carolina), this was a smoking gun. For the first time ever, a computer intruder had broken into a BellSouth central office switching station and re-programmed it! Or so BellSouth thought in June 1989. Actually, LoD members had been frolicking harmlessly in BellSouth switches since September 1987. The stunt of June 13--call-forwarding a number through manipulation of a switching station--was child's play for hackers as accomplished as the Georgia wing of LoD. Switching calls interstate sounded like a big deal, but it took only four lines of code to accomplish this. An easy, yet more discreet, stunt, would be to call-forward another number to your own house. If you were careful and considerate, and changed the software back later, then not a soul would know. Except you. And whoever you had bragged to about it. As for BellSouth, what they didn't know wouldn't hurt them. Except now somebody had blown the whole thing wide open, and BellSouth knew. A now alerted and considerably paranoid BellSouth began searching switches right and left for signs of impropriety, in that hot summer of 1989. No fewer than forty-two BellSouth employees were put on 12-hour shifts, twenty-four hours a day, for two solid months, poring over records and monitoring computers for any sign of phony access. These forty-two overworked experts were known as BellSouth's "Intrusion Task Force." What the investigators found astounded them. Proprietary telco databases had been manipulated: phone numbers had been created out of thin air, with no users' names and no addresses. And perhaps worst of all, no charges and no records of use. The new digital ReMOB (Remote Observation) diagnostic feature had been extensively tampered with--hackers had learned to reprogram ReMOB software, so that they could listen in on any switch-routed call at their leisure! They were using telco property to SPY! The electrifying news went out throughout law enforcement in 1989. It had never really occurred to anyone at BellSouth that their prized and brand-new digital switching-stations could be RE-PROGRAMMED. People seemed utterly amazed that anyone could have the nerve. Of course these switching stations were "computers," and everybody knew hackers liked to "break into computers:" but telephone people's computers were DIFFERENT from normal people's computers. The exact reason WHY these computers were "different" was rather ill-defined. It certainly wasn't the extent of their security. The security on these BellSouth computers was lousy; the AIMSX computers, for instance, didn't even have passwords. But there was no question that BellSouth strongly FELT that their computers were very different indeed. And if there were some criminals out there who had not gotten that message, BellSouth was determined to see that message taught. After all, a 5ESS switching station was no mere bookkeeping system for some local chain of florists. Public service depended on these stations. Public SAFETY depended on these stations. And hackers, lurking in there call-forwarding or ReMobbing, could spy on anybody in the local area! They could spy on telco officials! They could spy on police stations! They could spy on local offices of the Secret Service. . . . In 1989, electronic cops and hacker-trackers began using scrambler-phones and secured lines. It only made sense. There was no telling who was into those systems. Whoever they were, they sounded scary. This was some new level of antisocial daring. Could be West German hackers, in the pay of the KGB. That too had seemed a weird and farfetched notion, until Clifford Stoll had poked and prodded a sluggish Washington law-enforcement bureaucracy into investigating a computer intrusion that turned out to be exactly that--HACKERS, IN THE PAY OF THE KGB! Stoll, the systems manager for an Internet lab in Berkeley California, had ended up on the front page of the New Nork Times, proclaimed a national hero in the first true story of international computer espionage. Stoll's counterspy efforts, which he related in a bestselling book, The Cuckoo's Egg, in 1989, had established the credibility of `hacking' as a possible threat to national security. The United States Secret Service doesn't mess around when it suspects a possible action by a foreign intelligence apparat. The Secret Service scrambler-phones and secured lines put a tremendous kink in law enforcement's ability to operate freely; to get the word out, cooperate, prevent misunderstandings. Nevertheless, 1989 scarcely seemed the time for half-measures. If the police and Secret Service themselves were not operationally secure, then how could they reasonably demand measures of security from private enterprise? At least, the inconvenience made people aware of the seriousness of the threat. If there was a final spur needed to get the police off the dime, it came in the realization that the emergency 911 system was vulnerable. The 911 system has its own specialized software, but it is run on the same digital switching systems as the rest of the telephone network. 911 is not physically different from normal telephony. But it is certainly culturally different, because this is the area of telephonic cyberspace reserved for the police and emergency services. Your average policeman may not know much about hackers or phone-phreaks. Computer people are weird; even computer COPS are rather weird; the stuff they do is hard to figure out. But a threat to the 911 system is anything but an abstract threat. If the 911 system goes, people can die. Imagine being in a car-wreck, staggering to a phone-booth, punching 911 and hearing "Tina" pick up the phone-sex line somewhere in New York! The situation's no longer comical, somehow. And was it possible? No question. Hackers had attacked 911 systems before. Phreaks can max-out 911 systems just by siccing a bunch of computer-modems on them in tandem, dialling them over and over until they clog. That's very crude and low-tech, but it's still a serious business. The time had come for action. It was time to take stern measures with the underground. It was time to start picking up the dropped threads, the loose edges, the bits of braggadocio here and there; it was time to get on the stick and start putting serious casework together. Hackers weren't "invisible." They THOUGHT they were invisible; but the truth was, they had just been tolerated too long. Under sustained police attention in the summer of '89, the digital underground began to unravel as never before. The first big break in the case came very early on: July 1989, the following month. The perpetrator of the "Tina" switch was caught, and confessed. His name was "Fry Guy," a 16-year-old in Indiana. Fry Guy had been a very wicked young man. Fry Guy had earned his handle from a stunt involving French fries. Fry Guy had filched the log-in of a local MacDonald's manager and had logged-on to the MacDonald's mainframe on the Sprint Telenet system. Posing as the manager, Fry Guy had altered MacDonald's records, and given some teenage hamburger-flipping friends of his, generous raises. He had not been caught. Emboldened by success, Fry Guy moved on to credit-card abuse. Fry Guy was quite an accomplished talker; with a gift for "social engineering." If you can do "social engineering" --fast-talk, fake-outs, impersonation, conning, scamming-- then card abuse comes easy. (Getting away with it in the long run is another question). Fry Guy had run across "Urvile" of the Legion of Doom on the ALTOS Chat board in Bonn, Germany. ALTOS Chat was a sophisticated board, accessible through globe-spanning computer networks like BITnet, Tymnet, and Telenet. ALTOS was much frequented by members of Germany's Chaos Computer Club. Two Chaos hackers who hung out on ALTOS, "Jaeger" and "Pengo," had been the central villains of Clifford Stoll's Cuckoo's Egg case: consorting in East Berlin with a spymaster from the KGB, and breaking into American computers for hire, through the Internet. When LoD members learned the story of Jaeger's depredations from Stoll's book, they were rather less than impressed, technically speaking. On LoD's own favorite board of the moment, "Black Ice," LoD members bragged that they themselves could have done all the Chaos break-ins in a week flat! Nevertheless, LoD were grudgingly impressed by the Chaos rep, the sheer hairy-eyed daring of hash-smoking anarchist hackers who had rubbed shoulders with the fearsome big-boys of international Communist espionage. LoD members sometimes traded bits of knowledge with friendly German hackers on ALTOS--phone numbers for vulnerable VAX/VMS computers in Georgia, for instance. Dutch and British phone phreaks, and the Australian clique of "Phoenix," "Nom," and "Electron," were ALTOS regulars, too. In underground circles, to hang out on ALTOS was considered the sign of an elite dude, a sophisticated hacker of the international digital jet-set. Fry Guy quickly learned how to raid information from credit-card consumer-reporting agencies. He had over a hundred stolen credit-card numbers in his notebooks, and upwards of a thousand swiped long-distance access codes. He knew how to get onto Altos, and how to talk the talk of the underground convincingly. He now wheedled knowledge of switching-station tricks from Urvile on the ALTOS system. Combining these two forms of knowledge enabled Fry Guy to bootstrap his way up to a new form of wire-fraud. First, he'd snitched credit card numbers from credit-company computers. The data he copied included names, addresses and phone numbers of the random card-holders. Then Fry Guy, impersonating a card-holder, called up Western Union and asked for a cash advance on "his" credit card. Western Union, as a security guarantee, would call the customer back, at home, to verify the transaction. But, just as he had switched the Florida probation office to "Tina" in New York, Fry Guy switched the card-holder's number to a local pay-phone. There he would lurk in wait, muddying his trail by routing and re-routing the call, through switches as far away as Canada. When the call came through, he would boldly "social-engineer," or con, the Western Union people, pretending to be the legitimate card-holder. Since he'd answered the proper phone number, the deception was not very hard. Western Union's money was then shipped to a confederate of Fry Guy's in his home town in Indiana. Fry Guy and his cohort, using LoD techniques, stole six thousand dollars from Western Union between December 1988 and July 1989. They also dabbled in ordering delivery of stolen goods through card-fraud. Fry Guy was intoxicated with success. The sixteen-year-old fantasized wildly to hacker rivals, boasting that he'd used rip-off money to hire himself a big limousine, and had driven out-of-state with a groupie from his favorite heavy-metal band, Motley Crue. Armed with knowledge, power, and a gratifying stream of free money, Fry Guy now took it upon himself to call local representatives of Indiana Bell security, to brag, boast, strut, and utter tormenting warnings that his powerful friends in the notorious Legion of Doom could crash the national telephone network. Fry Guy even named a date for the scheme: the Fourth of July, a national holiday. This egregious example of the begging-for-arrest syndrome was shortly followed by Fry Guy's arrest. After the Indiana telephone company figured out who he was, the Secret Service had DNRs--Dialed Number Recorders-- installed on his home phone lines. These devices are not taps, and can't record the substance of phone calls, but they do record the phone numbers of all calls going in and out. Tracing these numbers showed Fry Guy's long-distance code fraud, his extensive ties to pirate bulletin boards, and numerous personal calls to his LoD friends in Atlanta. By July 11, 1989, Prophet, Urvile and Leftist also had Secret Service DNR "pen registers" installed on their own lines. The Secret Service showed up in force at Fry Guy's house on July 22, 1989, to the horror of his unsuspecting parents. The raiders were led by a special agent from the Secret Service's Indianapolis office. However, the raiders were accompanied and advised by Timothy M. Foley of the Secret Service's Chicago office (a gentleman about whom we will soon be hearing a great deal). Following federal computer-crime techniques that had been standard since the early 1980s, the Secret Service searched the house thoroughly, and seized all of Fry Guy's electronic equipment and notebooks. All Fry Guy's equipment went out the door in the custody of the Secret Service, which put a swift end to his depredations. The USSS interrogated Fry Guy at length. His case was put in the charge of Deborah Daniels, the federal US Attorney for the Southern District of Indiana. Fry Guy was charged with eleven counts of computer fraud, unauthorized computer access, and wire fraud. The evidence was thorough and irrefutable. For his part, Fry Guy blamed his corruption on the Legion of Doom and offered to testify against them. Fry Guy insisted that the Legion intended to crash the phone system on a national holiday. And when AT&T crashed on Martin Luther King Day, 1990, this lent a credence to his claim that genuinely alarmed telco security and the Secret Service. Fry Guy eventually pled guilty on May 31, 1990. On September 14, he was sentenced to forty-four months' probation and four hundred hours' community service. He could have had it much worse; but it made sense to prosecutors to take it easy on this teenage minor, while zeroing in on the notorious kingpins of the Legion of Doom. But the case against LoD had nagging flaws. Despite the best effort of investigators, it was impossible to prove that the Legion had crashed the phone system on January 15, because they, in fact, hadn't done so. The investigations of 1989 did show that certain members of the Legion of Doom had achieved unprecedented power over the telco switching stations, and that they were in active conspiracy to obtain more power yet. Investigators were privately convinced that the Legion of Doom intended to do awful things with this knowledge, but mere evil intent was not enough to put them in jail. And although the Atlanta Three--Prophet, Leftist, and especially Urvile-- had taught Fry Guy plenty, they were not themselves credit-card fraudsters. The only thing they'd "stolen" was long-distance service--and since they'd done much of that through phone-switch manipulation, there was no easy way to judge how much they'd "stolen," or whether this practice was even "theft" of any easily recognizable kind. Fry Guy's theft of long-distance codes had cost the phone companies plenty. The theft of long-distance service may be a fairly theoretical "loss," but it costs genuine money and genuine time to delete all those stolen codes, and to re-issue new codes to the innocent owners of those corrupted codes. The owners of the codes themselves are victimized, and lose time and money and peace of mind in the hassle. And then there were the credit-card victims to deal with, too, and Western Union. When it came to rip-off, Fry Guy was far more of a thief than LoD. It was only when it came to actual computer expertise that Fry Guy was small potatoes. The Atlanta Legion thought most "rules" of cyberspace were for rodents and losers, but they DID have rules. THEY NEVER CRASHED ANYTHING, AND THEY NEVER TOOK MONEY. These were rough rules-of-thumb, and rather dubious principles when it comes to the ethical subtleties of cyberspace, but they enabled the Atlanta Three to operate with a relatively clear conscience (though never with peace of mind). If you didn't hack for money, if you weren't robbing people of actual funds --money in the bank, that is-- then nobody REALLY got hurt, in LoD's opinion. "Theft of service" was a bogus issue, and "intellectual property" was a bad joke. But LoD had only elitist contempt for rip-off artists, "leechers," thieves. They considered themselves clean. In their opinion, if you didn't smash-up or crash any systems --(well, not on purpose, anyhow-- accidents can happen, just ask Robert Morris) then it was very unfair to call you a "vandal" or a "cracker." When you were hanging out on-line with your "pals" in telco security, you could face them down from the higher plane of hacker morality. And you could mock the police from the supercilious heights of your hacker's quest for pure knowledge. But from the point of view of law enforcement and telco security, however, Fry Guy was not really dangerous. The Atlanta Three WERE dangerous. It wasn't the crimes they were committing, but the DANGER, the potential hazard, the sheer TECHNICAL POWER LoD had accumulated, that had made the situation untenable. Fry Guy was not LoD. He'd never laid eyes on anyone in LoD; his only contacts with them had been electronic. Core members of the Legion of Doom tended to meet physically for conventions every year or so, to get drunk, give each other the hacker high-sign, send out for pizza and ravage hotel suites. Fry Guy had never done any of this. Deborah Daniels assessed Fry Guy accurately as "an LoD wannabe." Nevertheless Fry Guy's crimes would be directly attributed to LoD in much future police propaganda. LoD would be described as "a closely knit group" involved in "numerous illegal activities" including "stealing and modifying individual credit histories," and "fraudulently obtaining money and property." Fry Guy did this, but the Atlanta Three didn't; they simply weren't into theft, but rather intrusion. This caused a strange kink in the prosecution's strategy. LoD were accused of "disseminating information about attacking computers to other computer hackers in an effort to shift the focus of law enforcement to those other hackers and away from the Legion of Doom." This last accusation (taken directly from a press release by the Chicago Computer Fraud and Abuse Task Force) sounds particularly far-fetched. One might conclude at this point that investigators would have been well-advised to go ahead and "shift their focus" from the "Legion of Doom." Maybe they SHOULD concentrate on "those other hackers"--the ones who were actually stealing money and physical objects. But the Hacker Crackdown of 1990 was not a simple policing action. It wasn't meant just to walk the beat in cyberspace--it was a CRACKDOWN, a deliberate attempt to nail the core of the operation, to send a dire and potent message that would settle the hash of the digital underground for good. By this reasoning, Fry Guy wasn't much more than the electronic equivalent of a cheap streetcorner dope dealer. As long as the masterminds of LoD were still flagrantly operating, pushing their mountains of illicit knowledge right and left, and whipping up enthusiasm for blatant lawbreaking, then there would be an INFINITE SUPPLY of Fry Guys. Because LoD were flagrant, they had left trails everywhere, to be picked up by law enforcement in New York, Indiana, Florida, Texas, Arizona, Missouri, even Australia. But 1990's war on the Legion of Doom was led out of Illinois, by the Chicago Computer Fraud and Abuse Task Force. # The Computer Fraud and Abuse Task Force, led by federal prosecutor William J. Cook, had started in 1987 and had swiftly become one of the most aggressive local "dedicated computer-crime units." Chicago was a natural home for such a group. The world's first computer bulletin-board system had been invented in Illinois. The state of Illinois had some of the nation's first and sternest computer crime laws. Illinois State Police were markedly alert to the possibilities of white-collar crime and electronic fraud. And William J. Cook in particular was a rising star in electronic crime-busting. He and his fellow federal prosecutors at the U.S. Attorney's office in Chicago had a tight relation with the Secret Service, especially go-getting Chicago-based agent Timothy Foley. While Cook and his Department of Justice colleagues plotted strategy, Foley was their man on the street. Throughout the 1980s, the federal government had given prosecutors an armory of new, untried legal tools against computer crime. Cook and his colleagues were pioneers in the use of these new statutes in the real-life cut-and-thrust of the federal courtroom. On October 2, 1986, the US Senate had passed the "Computer Fraud and Abuse Act" unanimously, but there were pitifully few convictions under this statute. Cook's group took their name from this statute, since they were determined to transform this powerful but rather theoretical Act of Congress into a real-life engine of legal destruction against computer fraudsters and scofflaws. It was not a question of merely discovering crimes, investigating them, and then trying and punishing their perpetrators. The Chicago unit, like most everyone else in the business, already KNEW who the bad guys were: the Legion of Doom and the writers and editors of Phrack. The task at hand was to find some legal means of putting these characters away. This approach might seem a bit dubious, to someone not acquainted with the gritty realities of prosecutorial work. But prosecutors don't put people in jail for crimes they have committed; they put people in jail for crimes they have committed THAT CAN BE PROVED IN COURT. Chicago federal police put Al Capone in prison for income-tax fraud. Chicago is a big town, with a rough-and-ready bare-knuckle tradition on both sides of the law. Fry Guy had broken the case wide open and alerted telco security to the scope of the problem. But Fry Guy's crimes would not put the Atlanta Three behind bars--much less the wacko underground journalists of Phrack. So on July 22, 1989, the same day that Fry Guy was raided in Indiana, the Secret Service descended upon the Atlanta Three. This was likely inevitable. By the summer of 1989, law enforcement were closing in on the Atlanta Three from at least six directions at once. First, there were the leads from Fry Guy, which had led to the DNR registers being installed on the lines of the Atlanta Three. The DNR evidence alone would have finished them off, sooner or later. But second, the Atlanta lads were already well-known to Control-C and his telco security sponsors. LoD's contacts with telco security had made them overconfident and even more boastful than usual; they felt that they had powerful friends in high places, and that they were being openly tolerated by telco security. But BellSouth's Intrusion Task Force were hot on the trail of LoD and sparing no effort or expense. The Atlanta Three had also been identified by name and listed on the extensive anti-hacker files maintained, and retailed for pay, by private security operative John Maxfield of Detroit. Maxfield, who had extensive ties to telco security and many informants in the underground, was a bete noire of the Phrack crowd, and the dislike was mutual. The Atlanta Three themselves had written articles for Phrack. This boastful act could not possibly escape telco and law enforcement attention. "Knightmare," a high-school age hacker from Arizona, was a close friend and disciple of Atlanta LoD, but he had been nabbed by the formidable Arizona Organized Crime and Racketeering Unit. Knightmare was on some of LoD's favorite boards--"Black Ice" in particular-- and was privy to their secrets. And to have Gail Thackeray, the Assistant Attorney General of Arizona, on one's trail was a dreadful peril for any hacker. And perhaps worst of all, Prophet had committed a major blunder by passing an illicitly copied BellSouth computer-file to Knight Lightning, who had published it in Phrack. This, as we will see, was an act of dire consequence for almost everyone concerned. On July 22, 1989, the Secret Service showed up at the Leftist's house, where he lived with his parents. A massive squad of some twenty officers surrounded the building: Secret Service, federal marshals, local police, possibly BellSouth telco security; it was hard to tell in the crush. Leftist's dad, at work in his basement office, first noticed a muscular stranger in plain clothes crashing through the back yard with a drawn pistol. As more strangers poured into the house, Leftist's dad naturally assumed there was an armed robbery in progress. Like most hacker parents, Leftist's mom and dad had only the vaguest notions of what their son had been up to all this time. Leftist had a day-job repairing computer hardware. His obsession with computers seemed a bit odd, but harmless enough, and likely to produce a well- paying career. The sudden, overwhelming raid left Leftist's parents traumatized. The Leftist himself had been out after work with his co-workers, surrounding a couple of pitchers of margaritas. As he came trucking on tequila-numbed feet up the pavement, toting a bag full of floppy-disks, he noticed a large number of unmarked cars parked in his driveway. All the cars sported tiny microwave antennas. The Secret Service had knocked the front door off its hinges, almost flattening his mom. Inside, Leftist was greeted by Special Agent James Cool of the US Secret Service, Atlanta office. Leftist was flabbergasted. He'd never met a Secret Service agent before. He could not imagine that he'd ever done anything worthy of federal attention. He'd always figured that if his activities became intolerable, one of his contacts in telco security would give him a private phone-call and tell him to knock it off. But now Leftist was pat-searched for weapons by grim professionals, and his bag of floppies was quickly seized. He and his parents were all shepherded into separate rooms and grilled at length as a score of officers scoured their home for anything electronic. Leftist was horrified as his treasured IBM AT personal computer with its forty-meg hard disk, and his recently purchased 80386 IBM-clone with a whopping hundred-meg hard disk, both went swiftly out the door in Secret Service custody. They also seized all his disks, all his notebooks, and a tremendous booty in dogeared telco documents that Leftist had snitched out of trash dumpsters. Leftist figured the whole thing for a big misunderstanding. He'd never been into MILITARY computers. He wasn't a SPY or a COMMUNIST. He was just a good ol' Georgia hacker, and now he just wanted all these people out of the house. But it seemed they wouldn't go until he made some kind of statement. And so, he levelled with them. And that, Leftist said later from his federal prison camp in Talladega, Alabama, was a big mistake. The Atlanta area was unique, in that it had three members of the Legion of Doom who actually occupied more or less the same physical locality. Unlike the rest of LoD, who tended to associate by phone and computer, Atlanta LoD actually WERE "tightly knit." It was no real surprise that the Secret Service agents apprehending Urvile at the computer-labs at Georgia Tech, would discover Prophet with him as well. Urvile, a 21-year-old Georgia Tech student in polymer chemistry, posed quite a puzzling case for law enforcement. Urvile--also known as "Necron 99," as well as other handles, for he tended to change his cover-alias about once a month--was both an accomplished hacker and a fanatic simulation-gamer. Simulation games are an unusual hobby; but then hackers are unusual people, and their favorite pastimes tend to be somewhat out of the ordinary. The best-known American simulation game is probably "Dungeons & Dragons," a multi-player parlor entertainment played with paper, maps, pencils, statistical tables and a variety of oddly-shaped dice. Players pretend to be heroic characters exploring a wholly-invented fantasy world. The fantasy worlds of simulation gaming are commonly pseudo-medieval, involving swords and sorcery--spell-casting wizards, knights in armor, unicorns and dragons, demons and goblins. Urvile and his fellow gamers preferred their fantasies highly technological. They made use of a game known as "G.U.R.P.S.," the "Generic Universal Role Playing System," published by a company called Steve Jackson Games (SJG). "G.U.R.P.S." served as a framework for creating a wide variety of artificial fantasy worlds. Steve Jackson Games published a smorgasboard of books, full of detailed information and gaming hints, which were used to flesh-out many different fantastic backgrounds for the basic GURPS framework. Urvile made extensive use of two SJG books called GURPS High-Tech and GURPS Special Ops. In the artificial fantasy-world of GURPS Special Ops, players entered a modern fantasy of intrigue and international espionage. On beginning the game, players started small and powerless, perhaps as minor-league CIA agents or penny-ante arms dealers. But as players persisted through a series of game sessions (game sessions generally lasted for hours, over long, elaborate campaigns that might be pursued for months on end) then they would achieve new skills, new knowledge, new power. They would acquire and hone new abilities, such as marksmanship, karate, wiretapping, or Watergate burglary. They could also win various kinds of imaginary booty, like Berettas, or martini shakers, or fast cars with ejection seats and machine-guns under the headlights. As might be imagined from the complexity of these games, Urvile's gaming notes were very detailed and extensive. Urvile was a "dungeon-master," inventing scenarios for his fellow gamers, giant simulated adventure-puzzles for his friends to unravel. Urvile's game notes covered dozens of pages with all sorts of exotic lunacy, all about ninja raids on Libya and break-ins on encrypted Red Chinese supercomputers. His notes were written on scrap-paper and kept in loose-leaf binders. The handiest scrap paper around Urvile's college digs were the many pounds of BellSouth printouts and documents that he had snitched out of telco dumpsters. His notes were written on the back of misappropriated telco property. Worse yet, the gaming notes were chaotically interspersed with Urvile's hand-scrawled records involving ACTUAL COMPUTER INTRUSIONS that he had committed. Not only was it next to impossible to tell Urvile's fantasy game-notes from cyberspace "reality," but Urvile himself barely made this distinction. It's no exaggeration to say that to Urvile it was ALL a game. Urvile was very bright, highly imaginative, and quite careless of other people's notions of propriety. His connection to "reality" was not something to which he paid a great deal of attention. Hacking was a game for Urvile. It was an amusement he was carrying out, it was something he was doing for fun. And Urvile was an obsessive young man. He could no more stop hacking than he could stop in the middle of a jigsaw puzzle, or stop in the middle of reading a Stephen Donaldson fantasy trilogy. (The name "Urvile" came from a best-selling Donaldson novel.) Urvile's airy, bulletproof attitude seriously annoyed his interrogators. First of all, he didn't consider that he'd done anything wrong. There was scarcely a shred of honest remorse in him. On the contrary, he seemed privately convinced that his police interrogators were operating in a demented fantasy-world all their own. Urvile was too polite and well-behaved to say this straight-out, but his reactions were askew and disquieting. For instance, there was the business about LoD's ability to monitor phone-calls to the police and Secret Service. Urvile agreed that this was quite possible, and posed no big problem for LoD. In fact, he and his friends had kicked the idea around on the "Black Ice" board, much as they had discussed many other nifty notions, such as building personal flame-throwers and jury-rigging fistfulls of blasting-caps. They had hundreds of dial-up numbers for government agencies that they'd gotten through scanning Atlanta phones, or had pulled from raided VAX/VMS mainframe computers. Basically, they'd never gotten around to listening in on the cops because the idea wasn't interesting enough to bother with. Besides, if they'd been monitoring Secret Service phone calls, obviously they'd never have been caught in the first place. Right? The Secret Service was less than satisfied with this rapier-like hacker logic. Then there was the issue of crashing the phone system. No problem, Urvile admitted sunnily. Atlanta LoD could have shut down phone service all over Atlanta any time they liked. EVEN THE 911 SERVICE? Nothing special about that, Urvile explained patiently. Bring the switch to its knees, with say the UNIX "makedir" bug, and 911 goes down too as a matter of course. The 911 system wasn't very interesting, frankly. It might be tremendously interesting to cops (for odd reasons of their own), but as technical challenges went, the 911 service was yawnsville. So of course the Atlanta Three could crash service. They probably could have crashed service all over BellSouth territory, if they'd worked at it for a while. But Atlanta LoD weren't crashers. Only losers and rodents were crashers. LoD were ELITE. Urvile was privately convinced that sheer technical expertise could win him free of any kind of problem. As far as he was concerned, elite status in the digital underground had placed him permanently beyond the intellectual grasp of cops and straights. Urvile had a lot to learn. Of the three LoD stalwarts, Prophet was in the most direct trouble. Prophet was a UNIX programming expert who burrowed in and out of the Internet as a matter of course. He'd started his hacking career at around age 14, meddling with a UNIX mainframe system at the University of North Carolina. Prophet himself had written the handy Legion of Doom file "UNIX Use and Security From the Ground Up." UNIX (pronounced "you-nicks") is a powerful, flexible computer operating-system, for multi-user, multi-tasking computers. In 1969, when UNIX was created in Bell Labs, such computers were exclusive to large corporations and universities, but today UNIX is run on thousands of powerful home machines. UNIX was particularly well-suited to telecommunications programming, and had become a standard in the field. Naturally, UNIX also became a standard for the elite hacker and phone phreak. Lately, Prophet had not been so active as Leftist and Urvile, but Prophet was a recidivist. In 1986, when he was eighteen, Prophet had been convicted of "unauthorized access to a computer network" in North Carolina. He'd been discovered breaking into the Southern Bell Data Network, a UNIX-based internal telco network supposedly closed to the public. He'd gotten a typical hacker sentence: six months suspended, 120 hours community service, and three years' probation. After that humiliating bust, Prophet had gotten rid of most of his tonnage of illicit phreak and hacker data, and had tried to go straight. He was, after all, still on probation. But by the autumn of 1988, the temptations of cyberspace had proved too much for young Prophet, and he was shoulder-to-shoulder with Urvile and Leftist into some of the hairiest systems around. In early September 1988, he'd broken into BellSouth's centralized automation system, AIMSX or "Advanced Information Management System." AIMSX was an internal business network for BellSouth, where telco employees stored electronic mail, databases, memos, and calendars, and did text processing. Since AIMSX did not have public dial-ups, it was considered utterly invisible to the public, and was not well-secured --it didn't even require passwords. Prophet abused an account known as "waa1," the personal account of an unsuspecting telco employee. Disguised as the owner of waa1, Prophet made about ten visits to AIMSX. Prophet did not damage or delete anything in the system. His presence in AIMSX was harmless and almost invisible. But he could not rest content with that. One particular piece of processed text on AIMSX was a telco document known as "Bell South Standard Practice 660-225-104SV Control Office Administration of Enhanced 911 Services for Special Services and Major Account Centers dated March 1988." Prophet had not been looking for this document. It was merely one among hundreds of similar documents with impenetrable titles. However, having blundered over it in the course of his illicit wanderings through AIMSX, he decided to take it with him as a trophy. It might prove very useful in some future boasting, bragging, and strutting session. So, some time in September 1988, Prophet ordered the AIMSX mainframe computer to copy this document (henceforth called simply called "the E911 Document") and to transfer this copy to his home computer. No one noticed that Prophet had done this. He had "stolen" the E911 Document in some sense, but notions of property in cyberspace can be tricky. BellSouth noticed nothing wrong, because BellSouth still had their original copy. They had not been "robbed" of the document itself. Many people were supposed to copy this document--specifically, people who worked for the nineteen BellSouth "special services and major account centers," scattered throughout the Southeastern United States. That was what it was for, why it was present on a computer network in the first place: so that it could be copied and read-- by telco employees. But now the data had been copied by someone who wasn't supposed to look at it. Prophet now had his trophy. But he further decided to store yet another copy of the E911 Document on another person's computer. This unwitting person was a computer enthusiast named Richard Andrews who lived near Joliet, Illinois. Richard Andrews was a UNIX programmer by trade, and ran a powerful UNIX board called "Jolnet," in the basement of his house. Prophet, using the handle "Robert Johnson," had obtained an account on Richard Andrews' computer. And there he stashed the E911 Document, by storing it in his own private section of Andrews' computer. Why did Prophet do this? If Prophet had eliminated the E911 Document from his own computer, and kept it hundreds of miles away, on another machine, under an alias, then he might have been fairly safe from discovery and prosecution-- although his sneaky action had certainly put the unsuspecting Richard Andrews at risk. But, like most hackers, Prophet was a pack-rat for illicit data. When it came to the crunch, he could not bear to part from his trophy. When Prophet's place in Decatur, Georgia was raided in July 1989, there was the E911 Document, a smoking gun. And there was Prophet in the hands of the Secret Service, doing his best to "explain." Our story now takes us away from the Atlanta Three and their raids of the Summer of 1989. We must leave Atlanta Three "cooperating fully" with their numerous investigators. And all three of them did cooperate, as their Sentencing Memorandum from the US District Court of the Northern Division of Georgia explained--just before all three of them were sentenced to various federal prisons in November 1990. We must now catch up on the other aspects of the war on the Legion of Doom. The war on the Legion was a war on a network--in fact, a network of three networks, which intertwined and interrelated in a complex fashion. The Legion itself, with Atlanta LoD, and their hanger-on Fry Guy, were the first network. The second network was Phrack magazine, with its editors and contributors. The third network involved the electronic circle around a hacker known as "Terminus." The war against these hacker networks was carried out by a law enforcement network. Atlanta LoD and Fry Guy were pursued by USSS agents and federal prosecutors in Atlanta, Indiana, and Chicago. "Terminus" found himself pursued by USSS and federal prosecutors from Baltimore and Chicago. And the war against Phrack was almost entirely a Chicago operation. The investigation of Terminus involved a great deal of energy, mostly from the Chicago Task Force, but it was to be the least-known and least-publicized of the Crackdown operations. Terminus, who lived in Maryland, was a UNIX programmer and consultant, fairly well-known (under his given name) in the UNIX community, as an acknowledged expert on AT&T minicomputers. Terminus idolized AT&T, especially Bellcore, and longed for public recognition as a UNIX expert; his highest ambition was to work for Bell Labs. But Terminus had odd friends and a spotted history. Terminus had once been the subject of an admiring interview in Phrack (Volume II, Issue 14, Phile 2--dated May 1987). In this article, Phrack co-editor Taran King described "Terminus" as an electronics engineer, 5'9", brown-haired, born in 1959--at 28 years old, quite mature for a hacker. Terminus had once been sysop of a phreak/hack underground board called "MetroNet," which ran on an Apple II. Later he'd replaced "MetroNet" with an underground board called "MegaNet," specializing in IBMs. In his younger days, Terminus had written one of the very first and most elegant code-scanning programs for the IBM-PC. This program had been widely distributed in the underground. Uncounted legions of PC-owning phreaks and hackers had used Terminus's scanner program to rip-off telco codes. This feat had not escaped the attention of telco security; it hardly could, since Terminus's earlier handle, "Terminal Technician," was proudly written right on the program. When he became a full-time computer professional (specializing in telecommunications programming), he adopted the handle Terminus, meant to indicate that he had "reached the final point of being a proficient hacker." He'd moved up to the UNIX-based "Netsys" board on an AT&T computer, with four phone lines and an impressive 240 megs of storage. "Netsys" carried complete issues of Phrack, and Terminus was quite friendly with its publishers, Taran King and Knight Lightning. In the early 1980s, Terminus had been a regular on Plovernet, Pirate-80, Sherwood Forest and Shadowland, all well-known pirate boards, all heavily frequented by the Legion of Doom. As it happened, Terminus was never officially "in LoD," because he'd never been given the official LoD high-sign and back-slap by Legion maven Lex Luthor. Terminus had never physically met anyone from LoD. But that scarcely mattered much-- the Atlanta Three themselves had never been officially vetted by Lex, either. As far as law enforcement was concerned, the issues were clear. Terminus was a full-time, adult computer professional with particular skills at AT&T software and hardware-- but Terminus reeked of the Legion of Doom and the underground. On February 1, 1990--half a month after the Martin Luther King Day Crash-- USSS agents Tim Foley from Chicago, and Jack Lewis from the Baltimore office, accompanied by AT&T security officer Jerry Dalton, travelled to Middle Town, Maryland. There they grilled Terminus in his home (to the stark terror of his wife and small children), and, in their customary fashion, hauled his computers out the door. The Netsys machine proved to contain a plethora of arcane UNIX software-- proprietary source code formally owned by AT&T. Software such as: UNIX System Five Release 3.2; UNIX SV Release 3.1; UUCP communications software; KORN SHELL; RFS; IWB; WWB; DWB; the C++ programming language; PMON; TOOL CHEST; QUEST; DACT, and S FIND. In the long-established piratical tradition of the underground, Terminus had been trading this illicitly-copied software with a small circle of fellow UNIX programmers. Very unwisely, he had stored seven years of his electronic mail on his Netsys machine, which documented all the friendly arrangements he had made with his various colleagues. Terminus had not crashed the AT&T phone system on January 15. He was, however, blithely running a not-for-profit AT&T software-piracy ring. This was not an activity AT&T found amusing. AT&T security officer Jerry Dalton valued this "stolen" property at over three hundred thousand dollars. AT&T's entry into the tussle of free enterprise had been complicated by the new, vague groundrules of the information economy. Until the break-up of Ma Bell, AT&T was forbidden to sell computer hardware or software. Ma Bell was the phone company; Ma Bell was not allowed to use the enormous revenue from telephone utilities, in order to finance any entry into the computer market. AT&T nevertheless invented the UNIX operating system. And somehow AT&T managed to make UNIX a minor source of income. Weirdly, UNIX was not sold as computer software, but actually retailed under an obscure regulatory exemption allowing sales of surplus equipment and scrap. Any bolder attempt to promote or retail UNIX would have aroused angry legal opposition from computer companies. Instead, UNIX was licensed to universities, at modest rates, where the acids of academic freedom ate away steadily at AT&T's proprietary rights. Come the breakup, AT&T recognized that UNIX was a potential gold-mine. By now, large chunks of UNIX code had been created that were not AT&T's, and were being sold by others. An entire rival UNIX-based operating system had arisen in Berkeley, California (one of the world's great founts of ideological hackerdom). Today, "hackers" commonly consider "Berkeley UNIX" to be technically superior to AT&T's "System V UNIX," but AT&T has not allowed mere technical elegance to intrude on the real-world business of marketing proprietary software. AT&T has made its own code deliberately incompatible with other folks' UNIX, and has written code that it can prove is copyrightable, even if that code happens to be somewhat awkward--"kludgey." AT&T UNIX user licenses are serious business agreements, replete with very clear copyright statements and non-disclosure clauses. AT&T has not exactly kept the UNIX cat in the bag, but it kept a grip on its scruff with some success. By the rampant, explosive standards of software piracy, AT&T UNIX source code is heavily copyrighted, well-guarded, well-licensed. UNIX was traditionally run only on mainframe machines, owned by large groups of suit-and-tie professionals, rather than on bedroom machines where people can get up to easy mischief. And AT&T UNIX source code is serious high-level programming. The number of skilled UNIX programmers with any actual motive to swipe UNIX source code is small. It's tiny, compared to the tens of thousands prepared to rip-off, say, entertaining PC games like "Leisure Suit Larry." But by 1989, the warez-d00d underground, in the persons of Terminus and his friends, was gnawing at AT&T UNIX. And the property in question was not sold for twenty bucks over the counter at the local branch of Babbage's or Egghead's; this was massive, sophisticated, multi-line, multi-author corporate code worth tens of thousands of dollars. It must be recognized at this point that Terminus's purported ring of UNIX software pirates had not actually made any money from their suspected crimes. The $300,000 dollar figure bandied about for the contents of Terminus's computer did not mean that Terminus was in actual illicit possession of three hundred thousand of AT&T's dollars. Terminus was shipping software back and forth, privately, person to person, for free. He was not making a commercial business of piracy. He hadn't asked for money; he didn't take money. He lived quite modestly. AT&T employees--as well as freelance UNIX consultants, like Terminus-- commonly worked with "proprietary" AT&T software, both in the office and at home on their private machines. AT&T rarely sent security officers out to comb the hard disks of its consultants. Cheap freelance UNIX contractors were quite useful to AT&T; they didn't have health insurance or retirement programs, much less union membership in the Communication Workers of America. They were humble digital drudges, wandering with mop and bucket through the Great Technological Temple of AT&T; but when the Secret Service arrived at their homes, it seemed they were eating with company silverware and sleeping on company sheets! Outrageously, they behaved as if the things they worked with every day belonged to them! And these were no mere hacker teenagers with their hands full of trash-paper and their noses pressed to the corporate windowpane. These guys were UNIX wizards, not only carrying AT&T data in their machines and their heads, but eagerly networking about it, over machines that were far more powerful than anything previously imagined in private hands. How do you keep people disposable, yet assure their awestruck respect for your property? It was a dilemma. Much UNIX code was public-domain, available for free. Much "proprietary" UNIX code had been extensively re-written, perhaps altered so much that it became an entirely new product--or perhaps not. Intellectual property rights for software developers were, and are, extraordinarily complex and confused. And software "piracy," like the private copying of videos, is one of the most widely practiced "crimes" in the world today. The USSS were not experts in UNIX or familiar with the customs of its use. The United States Secret Service, considered as a body, did not have one single person in it who could program in a UNIX environment--no, not even one. The Secret Service WERE making extensive use of expert help, but the "experts" they had chosen were AT&T and Bellcore security officials, the very victims of the purported crimes under investigation, the very people whose interest in AT&T's "proprietary" software was most pronounced. On February 6, 1990, Terminus was arrested by Agent Lewis. Eventually, Terminus would be sent to prison for his illicit use of a piece of AT&T software. The issue of pirated AT&T software would bubble along in the background during the war on the Legion of Doom. Some half-dozen of Terminus's on-line acquaintances, including people in Illinois, Texas and California, were grilled by the Secret Service in connection with the illicit copying of software. Except for Terminus, however, none were charged with a crime. None of them shared his peculiar prominence in the hacker underground. But that did not mean that these people would, or could, stay out of trouble. The transferral of illicit data in cyberspace is hazy and ill-defined business, with paradoxical dangers for everyone concerned: hackers, signal carriers, board owners, cops, prosecutors, even random passers-by. Sometimes, well-meant attempts to avert trouble or punish wrongdoing bring more trouble than would simple ignorance, indifference or impropriety. Terminus's "Netsys" board was not a common-or-garden bulletin board system, though it had most of the usual functions of a board. Netsys was not a stand-alone machine, but part of the globe-spanning "UUCP" cooperative network. The UUCP network uses a set of Unix software programs called "Unix-to-Unix Copy," which allows Unix systems to throw data to one another at high speed through the public telephone network. UUCP is a radically decentralized, not-for-profit network of UNIX computers. There are tens of thousands of these UNIX machines. Some are small, but many are powerful and also link to other networks. UUCP has certain arcane links to major networks such as JANET, EasyNet, BITNET, JUNET, VNET, DASnet, PeaceNet and FidoNet, as well as the gigantic Internet. (The so-called "Internet" is not actually a network itself, but rather an "internetwork" connections standard that allows several globe-spanning computer networks to communicate with one another. Readers fascinated by the weird and intricate tangles of modern computer networks may enjoy John S. Quarterman's authoritative 719-page explication, The Matrix, Digital Press, 1990.) A skilled user of Terminus' UNIX machine could send and receive electronic mail from almost any major computer network in the world. Netsys was not called a "board" per se, but rather a "node." "Nodes" were larger, faster, and more sophisticated than mere "boards," and for hackers, to hang out on internationally-connected "nodes" was quite the step up from merely hanging out on local "boards." Terminus's Netsys node in Maryland had a number of direct links to other, similar UUCP nodes, run by people who shared his interests and at least something of his free-wheeling attitude. One of these nodes was Jolnet, owned by Richard Andrews, who, like Terminus, was an independent UNIX consultant. Jolnet also ran UNIX, and could be contacted at high speed by mainframe machines from all over the world. Jolnet was quite a sophisticated piece of work, technically speaking, but it was still run by an individual, as a private, not-for-profit hobby. Jolnet was mostly used by other UNIX programmers--for mail, storage, and access to networks. Jolnet supplied access network access to about two hundred people, as well as a local junior college. Among its various features and services, Jolnet also carried Phrack magazine. For reasons of his own, Richard Andrews had become suspicious of a new user called "Robert Johnson." Richard Andrews took it upon himself to have a look at what "Robert Johnson" was storing in Jolnet. And Andrews found the E911 Document. "Robert Johnson" was the Prophet from the Legion of Doom, and the E911 Document was illicitly copied data from Prophet's raid on the BellSouth computers. The E911 Document, a particularly illicit piece of digital property, was about to resume its long, complex, and disastrous career. It struck Andrews as fishy that someone not a telephone employee should have a document referring to the "Enhanced 911 System." Besides, the document itself bore an obvious warning. "WARNING: NOT FOR USE OR DISCLOSURE OUTSIDE BELLSOUTH OR ANY OF ITS SUBSIDIARIES EXCEPT UNDER WRITTEN AGREEMENT." These standard nondisclosure tags are often appended to all sorts of corporate material. Telcos as a species are particularly notorious for stamping most everything in sight as "not for use or disclosure." Still, this particular piece of data was about the 911 System. That sounded bad to Rich Andrews. Andrews was not prepared to ignore this sort of trouble. He thought it would be wise to pass the document along to a friend and acquaintance on the UNIX network, for consultation. So, around September 1988, Andrews sent yet another copy of the E911 Document electronically to an AT&T employee, one Charles Boykin, who ran a UNIX-based node called "attctc" in Dallas, Texas. "Attctc" was the property of AT&T, and was run from AT&T's Customer Technology Center in Dallas, hence the name "attctc." "Attctc" was better-known as "Killer," the name of the machine that the system was running on. "Killer" was a hefty, powerful, AT&T 3B2 500 model, a multi-user, multi-tasking UNIX platform with 32 meg of memory and a mind-boggling 3.2 Gigabytes of storage. When Killer had first arrived in Texas, in 1985, the 3B2 had been one of AT&T's great white hopes for going head-to-head with IBM for the corporate computer-hardware market. "Killer" had been shipped to the Customer Technology Center in the Dallas Infomart, essentially a high-technology mall, and there it sat, a demonstration model. Charles Boykin, a veteran AT&T hardware and digital communications expert, was a local technical backup man for the AT&T 3B2 system. As a display model in the Infomart mall, "Killer" had little to do, and it seemed a shame to waste the system's capacity. So Boykin ingeniously wrote some UNIX bulletin-board software for "Killer," and plugged the machine in to the local phone network. "Killer's" debut in late 1985 made it the first publicly available UNIX site in the state of Texas. Anyone who wanted to play was welcome. The machine immediately attracted an electronic community. It joined the UUCP network, and offered network links to over eighty other computer sites, all of which became dependent on Killer for their links to the greater world of cyberspace. And it wasn't just for the big guys; personal computer users also stored freeware programs for the Amiga, the Apple, the IBM and the Macintosh on Killer's vast 3,200 meg archives. At one time, Killer had the largest library of public-domain Macintosh software in Texas. Eventually, Killer attracted about 1,500 users, all busily communicating, uploading and downloading, getting mail, gossipping, and linking to arcane and distant networks. Boykin received no pay for running Killer. He considered it good publicity for the AT&T 3B2 system (whose sales were somewhat less than stellar), but he also simply enjoyed the vibrant community his skill had created. He gave away the bulletin-board UNIX software he had written, free of charge. In the UNIX programming community, Charlie Boykin had the reputation of a warm, open-hearted, level-headed kind of guy. In 1989, a group of Texan UNIX professionals voted Boykin "System Administrator of the Year." He was considered a fellow you could trust for good advice. In September 1988, without warning, the E911 Document came plunging into Boykin's life, forwarded by Richard Andrews. Boykin immediately recognized that the Document was hot property. He was not a voice-communications man, and knew little about the ins and outs of the Baby Bells, but he certainly knew what the 911 System was, and he was angry to see confidential data about it in the hands of a nogoodnik. This was clearly a matter for telco security. So, on September 21, 1988, Boykin made yet ANOTHER copy of the E911 Document and passed this one along to a professional acquaintance of his, one Jerome Dalton, from AT&T Corporate Information Security. Jerry Dalton was the very fellow who would later raid Terminus's house. From AT&T's security division, the E911 Document went to Bellcore. Bellcore (or BELL COmmunications REsearch) had once been the central laboratory of the Bell System. Bell Labs employees had invented the UNIX operating system. Now Bellcore was a quasi-independent, jointly owned company that acted as the research arm for all seven of the Baby Bell RBOCs. Bellcore was in a good position to co-ordinate security technology and consultation for the RBOCs, and the gentleman in charge of this effort was Henry M. Kluepfel, a veteran of the Bell System who had worked there for twenty-four years. On October 13, 1988, Dalton passed the E911 Document to Henry Kluepfel. Kluepfel, a veteran expert witness in telecommunications fraud and computer-fraud cases, had certainly seen worse trouble than this. He recognized the document for what it was: a trophy from a hacker break-in. However, whatever harm had been done in the intrusion was presumably old news. At this point there seemed little to be done. Kluepfel made a careful note of the circumstances and shelved the problem for the time being. Whole months passed. February 1989 arrived. The Atlanta Three were living it up in Bell South's switches, and had not yet met their comeuppance. The Legion was thriving. So was Phrack magazine. A good six months had passed since Prophet's AIMSX break-in. Prophet, as hackers will, grew weary of sitting on his laurels. "Knight Lightning" and "Taran King," the editors of Phrack, were always begging Prophet for material they could publish. Prophet decided that the heat must be off by this time, and that he could safely brag, boast, and strut. So he sent a copy of the E911 Document--yet another one-- from Rich Andrews' Jolnet machine to Knight Lightning's BITnet account at the University of Missouri. Let's review the fate of the document so far. 0. The original E911 Document. This in the AIMSX system on a mainframe computer in Atlanta, available to hundreds of people, but all of them, presumably, BellSouth employees. An unknown number of them may have their own copies of this document, but they are all professionals and all trusted by the phone company. 1. Prophet's illicit copy, at home on his own computer in Decatur, Georgia. 2. Prophet's back-up copy, stored on Rich Andrew's Jolnet machine in the basement of Rich Andrews' house near Joliet Illinois. 3. Charles Boykin's copy on "Killer" in Dallas, Texas, sent by Rich Andrews from Joliet. 4. Jerry Dalton's copy at AT&T Corporate Information Security in New Jersey, sent from Charles Boykin in Dallas. 5. Henry Kluepfel's copy at Bellcore security headquarters in New Jersey, sent by Dalton. 6. Knight Lightning's copy, sent by Prophet from Rich Andrews' machine, and now in Columbia, Missouri. We can see that the "security" situation of this proprietary document, once dug out of AIMSX, swiftly became bizarre. Without any money changing hands, without any particular special effort, this data had been reproduced at least six times and had spread itself all over the continent. By far the worst, however, was yet to come. In February 1989, Prophet and Knight Lightning bargained electronically over the fate of this trophy. Prophet wanted to boast, but, at the same time, scarcely wanted to be caught. For his part, Knight Lightning was eager to publish as much of the document as he could manage. Knight Lightning was a fledgling political-science major with a particular interest in freedom-of-information issues. He would gladly publish most anything that would reflect glory on the prowess of the underground and embarrass the telcos. However, Knight Lightning himself had contacts in telco security, and sometimes consulted them on material he'd received that might be too dicey for publication. Prophet and Knight Lightning decided to edit the E911 Document so as to delete most of its identifying traits. First of all, its large "NOT FOR USE OR DISCLOSURE" warning had to go. Then there were other matters. For instance, it listed the office telephone numbers of several BellSouth 911 specialists in Florida. If these phone numbers were published in Phrack, the BellSouth employees involved would very likely be hassled by phone phreaks, which would anger BellSouth no end, and pose a definite operational hazard for both Prophet and Phrack. So Knight Lightning cut the Document almost in half, removing the phone numbers and some of the touchier and more specific information. He passed it back electronically to Prophet; Prophet was still nervous, so Knight Lightning cut a bit more. They finally agreed that it was ready to go, and that it would be published in Phrack under the pseudonym, "The Eavesdropper." And this was done on February 25, 1989. The twenty-fourth issue of Phrack featured a chatty interview with co-ed phone-phreak "Chanda Leir," three articles on BITNET and its links to other computer networks, an article on 800 and 900 numbers by "Unknown User," "VaxCat's" article on telco basics (slyly entitled "Lifting Ma Bell's Veil of Secrecy,)" and the usual "Phrack World News." The News section, with painful irony, featured an extended account of the sentencing of "Shadowhawk," an eighteen-year-old Chicago hacker who had just been put in federal prison by William J. Cook himself. And then there were the two articles by "The Eavesdropper." The first was the edited E911 Document, now titled "Control Office Administration Of Enhanced 911 Services for Special Services and Major Account Centers." Eavesdropper's second article was a glossary of terms explaining the blizzard of telco acronyms and buzzwords in the E911 Document. The hapless document was now distributed, in the usual Phrack routine, to a good one hundred and fifty sites. Not a hundred and fifty PEOPLE, mind you--a hundred and fifty SITES, some of these sites linked to UNIX nodes or bulletin board systems, which themselves had readerships of tens, dozens, even hundreds of people. This was February 1989. Nothing happened immediately. Summer came, and the Atlanta crew were raided by the Secret Service. Fry Guy was apprehended. Still nothing whatever happened to Phrack. Six more issues of Phrack came out, 30 in all, more or less on a monthly schedule. Knight Lightning and co-editor Taran King went untouched. Phrack tended to duck and cover whenever the heat came down. During the summer busts of 1987--(hacker busts tended to cluster in summer, perhaps because hackers were easier to find at home than in college)-- Phrack had ceased publication for several months, and laid low. Several LoD hangers-on had been arrested, but nothing had happened to the Phrack crew, the premiere gossips of the underground. In 1988, Phrack had been taken over by a new editor, "Crimson Death," a raucous youngster with a taste for anarchy files. 1989, however, looked like a bounty year for the underground. Knight Lightning and his co-editor Taran King took up the reins again, and Phrack flourished throughout 1989. Atlanta LoD went down hard in the summer of 1989, but Phrack rolled merrily on. Prophet's E911 Document seemed unlikely to cause Phrack any trouble. By January 1990, it had been available in Phrack for almost a year. Kluepfel and Dalton, officers of Bellcore and AT&T security, had possessed the document for sixteen months--in fact, they'd had it even before Knight Lightning himself, and had done nothing in particular to stop its distribution. They hadn't even told Rich Andrews or Charles Boykin to erase the copies from their UNIX nodes, Jolnet and Killer. But then came the monster Martin Luther King Day Crash of January 15, 1990. A flat three days later, on January 18, four agents showed up at Knight Lightning's fraternity house. One was Timothy Foley, the second Barbara Golden, both of them Secret Service agents from the Chicago office. Also along was a University of Missouri security officer, and Reed Newlin, a security man from Southwestern Bell, the RBOC having jurisdiction over Missouri. Foley accused Knight Lightning of causing the nationwide crash of the phone system. Knight Lightning was aghast at this allegation. On the face of it, the suspicion was not entirely implausible--though Knight Lightning knew that he himself hadn't done it. Plenty of hot-dog hackers had bragged that they could crash the phone system, however. "Shadowhawk," for instance, the Chicago hacker whom William Cook had recently put in jail, had several times boasted on boards that he could "shut down AT&T's public switched network." And now this event, or something that looked just like it, had actually taken place. The Crash had lit a fire under the Chicago Task Force. And the former fence-sitters at Bellcore and AT&T were now ready to roll. The consensus among telco security--already horrified by the skill of the BellSouth intruders --was that the digital underground was out of hand. LoD and Phrack must go. And in publishing Prophet's E911 Document, Phrack had provided law enforcement with what appeared to be a powerful legal weapon. Foley confronted Knight Lightning about the E911 Document. Knight Lightning was cowed. He immediately began "cooperating fully" in the usual tradition of the digital underground. He gave Foley a complete run of Phrack, printed out in a set of three-ring binders. He handed over his electronic mailing list of Phrack subscribers. Knight Lightning was grilled for four hours by Foley and his cohorts. Knight Lightning admitted that Prophet had passed him the E911 Document, and he admitted that he had known it was stolen booty from a hacker raid on a telephone company. Knight Lightning signed a statement to this effect, and agreed, in writing, to cooperate with investigators. Next day--January 19, 1990, a Friday --the Secret Service returned with a search warrant, and thoroughly searched Knight Lightning's upstairs room in the fraternity house. They took all his floppy disks, though, interestingly, they left Knight Lightning in possession of both his computer and his modem. (The computer had no hard disk, and in Foley's judgement was not a store of evidence.) But this was a very minor bright spot among Knight Lightning's rapidly multiplying troubles. By this time, Knight Lightning was in plenty of hot water, not only with federal police, prosecutors, telco investigators, and university security, but with the elders of his own campus fraternity, who were outraged to think that they had been unwittingly harboring a federal computer-criminal. On Monday, Knight Lightning was summoned to Chicago, where he was further grilled by Foley and USSS veteran agent Barbara Golden, this time with an attorney present. And on Tuesday, he was formally indicted by a federal grand jury. The trial of Knight Lightning, which occurred on July 24-27, 1990, was the crucial show-trial of the Hacker Crackdown. We will examine the trial at some length in Part Four of this book. In the meantime, we must continue our dogged pursuit of the E911 Document. It must have been clear by January 1990 that the E911 Document, in the form Phrack had published it back in February 1989, had gone off at the speed of light in at least a hundred and fifty different directions. To attempt to put this electronic genie back in the bottle was flatly impossible. And yet, the E911 Document was STILL stolen property, formally and legally speaking. Any electronic transference of this document, by anyone unauthorized to have it, could be interpreted as an act of wire fraud. Interstate transfer of stolen property, including electronic property, was a federal crime. The Chicago Computer Fraud and Abuse Task Force had been assured that the E911 Document was worth a hefty sum of money. In fact, they had a precise estimate of its worth from BellSouth security personnel: $79,449. A sum of this scale seemed to warrant vigorous prosecution. Even if the damage could not be undone, at least this large sum offered a good legal pretext for stern punishment of the thieves. It seemed likely to impress judges and juries. And it could be used in court to mop up the Legion of Doom. The Atlanta crowd was already in the bag, by the time the Chicago Task Force had gotten around to Phrack. But the Legion was a hydra-headed thing. In late 89, a brand-new Legion of Doom board, "Phoenix Project," had gone up in Austin, Texas. Phoenix Project was sysoped by no less a man than the Mentor himself, ably assisted by University of Texas student and hardened Doomster "Erik Bloodaxe." As we have seen from his Phrack manifesto, the Mentor was a hacker zealot who regarded computer intrusion as something close to a moral duty. Phoenix Project was an ambitious effort, intended to revive the digital underground to what Mentor considered the full flower of the early 80s. The Phoenix board would also boldly bring elite hackers face-to-face with the telco "opposition." On "Phoenix," America's cleverest hackers would supposedly shame the telco squareheads out of their stick-in-the-mud attitudes, and perhaps convince them that the Legion of Doom elite were really an all-right crew. The premiere of "Phoenix Project" was heavily trumpeted by Phrack,and "Phoenix Project" carried a complete run of Phrack issues, including the E911 Document as Phrack had published it. Phoenix Project was only one of many--possibly hundreds--of nodes and boards all over America that were in guilty possession of the E911 Document. But Phoenix was an outright, unashamed Legion of Doom board. Under Mentor's guidance, it was flaunting itself in the face of telco security personnel. Worse yet, it was actively trying to WIN THEM OVER as sympathizers for the digital underground elite. "Phoenix" had no cards or codes on it. Its hacker elite considered Phoenix at least technically legal. But Phoenix was a corrupting influence, where hacker anarchy was eating away like digital acid at the underbelly of corporate propriety. The Chicago Computer Fraud and Abuse Task Force now prepared to descend upon Austin, Texas. Oddly, not one but TWO trails of the Task Force's investigation led toward Austin. The city of Austin, like Atlanta, had made itself a bulwark of the Sunbelt's Information Age, with a strong university research presence, and a number of cutting-edge electronics companies, including Motorola, Dell, CompuAdd, IBM, Sematech and MCC. Where computing machinery went, hackers generally followed. Austin boasted not only "Phoenix Project," currently LoD's most flagrant underground board, but a number of UNIX nodes. One of these nodes was "Elephant," run by a UNIX consultant named Robert Izenberg. Izenberg, in search of a relaxed Southern lifestyle and a lowered cost-of-living, had recently migrated to Austin from New Jersey. In New Jersey, Izenberg had worked for an independent contracting company, programming UNIX code for AT&T itself. "Terminus" had been a frequent user on Izenberg's privately owned Elephant node. Having interviewed Terminus and examined the records on Netsys, the Chicago Task Force were now convinced that they had discovered an underground gang of UNIX software pirates, who were demonstrably guilty of interstate trafficking in illicitly copied AT&T source code. Izenberg was swept into the dragnet around Terminus, the self-proclaimed ultimate UNIX hacker. Izenberg, in Austin, had settled down into a UNIX job with a Texan branch of IBM. Izenberg was no longer working as a contractor for AT&T, but he had friends in New Jersey, and he still logged on to AT&T UNIX computers back in New Jersey, more or less whenever it pleased him. Izenberg's activities appeared highly suspicious to the Task Force. Izenberg might well be breaking into AT&T computers, swiping AT&T software, and passing it to Terminus and other possible confederates, through the UNIX node network. And this data was worth, not merely $79,499, but hundreds of thousands of dollars! On February 21, 1990, Robert Izenberg arrived home from work at IBM to find that all the computers had mysteriously vanished from his Austin apartment. Naturally he assumed that he had been robbed. His "Elephant" node, his other machines, his notebooks, his disks, his tapes, all gone! However, nothing much else seemed disturbed--the place had not been ransacked. The puzzle becaming much stranger some five minutes later. Austin U. S. Secret Service Agent Al Soliz, accompanied by University of Texas campus-security officer Larry Coutorie and the ubiquitous Tim Foley, made their appearance at Izenberg's door. They were in plain clothes: slacks, polo shirts. They came in, and Tim Foley accused Izenberg of belonging to the Legion of Doom. Izenberg told them that he had never heard of the "Legion of Doom." And what about a certain stolen E911 Document, that posed a direct threat to the police emergency lines? Izenberg claimed that he'd never heard of that, either. His interrogators found this difficult to believe. Didn't he know Terminus? Who? They gave him Terminus's real name. Oh yes, said Izenberg. He knew THAT guy all right--he was leading discussions on the Internet about AT&T computers, especially the AT&T 3B2. AT&T had thrust this machine into the marketplace, but, like many of AT&T's ambitious attempts to enter the computing arena, the 3B2 project had something less than a glittering success. Izenberg himself had been a contractor for the division of AT&T that supported the 3B2. The entire division had been shut down. Nowadays, the cheapest and quickest way to get help with this fractious piece of machinery was to join one of Terminus's discussion groups on the Internet, where friendly and knowledgeable hackers would help you for free. Naturally the remarks within this group were less than flattering about the Death Star. . .was THAT the problem? Foley told Izenberg that Terminus had been acquiring hot software through his, Izenberg's, machine. Izenberg shrugged this off. A good eight megabytes of data flowed through his UUCP site every day. UUCP nodes spewed data like fire hoses. Elephant had been directly linked to Netsys--not surprising, since Terminus was a 3B2 expert and Izenberg had been a 3B2 contractor. Izenberg was also linked to "attctc" and the University of Texas. Terminus was a well-known UNIX expert, and might have been up to all manner of hijinks on Elephant. Nothing Izenberg could do about that. That was physically impossible. Needle in a haystack. In a four-hour grilling, Foley urged Izenberg to come clean and admit that he was in conspiracy with Terminus, and a member of the Legion of Doom. Izenberg denied this. He was no weirdo teenage hacker-- he was thirty-two years old, and didn't even have a "handle." Izenberg was a former TV technician and electronics specialist who had drifted into UNIX consulting as a full-grown adult. Izenberg had never met Terminus, physically. He'd once bought a cheap high-speed modem from him, though. Foley told him that this modem (a Telenet T2500 which ran at 19.2 kilobaud, and which had just gone out Izenberg's door in Secret Service custody) was likely hot property. Izenberg was taken aback to hear this; but then again, most of Izenberg's equipment, like that of most freelance professionals in the industry, was discounted, passed hand-to-hand through various kinds of barter and gray-market. There was no proof that the modem was stolen, and even if it were, Izenberg hardly saw how that gave them the right to take every electronic item in his house. Still, if the United States Secret Service figured they needed his computer for national security reasons--or whatever-- then Izenberg would not kick. He figured he would somehow make the sacrifice of his twenty thousand dollars' worth of professional equipment, in the spirit of full cooperation and good citizenship. Robert Izenberg was not arrested. Izenberg was not charged with any crime. His UUCP node--full of some 140 megabytes of the files, mail, and data of himself and his dozen or so entirely innocent users--went out the door as "evidence." Along with the disks and tapes, Izenberg had lost about 800 megabytes of data. Six months would pass before Izenberg decided to phone the Secret Service and ask how the case was going. That was the first time that Robert Izenberg would ever hear the name of William Cook. As of January 1992, a full two years after the seizure, Izenberg, still not charged with any crime, would be struggling through the morass of the courts, in hope of recovering his thousands of dollars' worth of seized equipment. In the meantime, the Izenberg case received absolutely no press coverage. The Secret Service had walked into an Austin home, removed a UNIX bulletin- board system, and met with no operational difficulties whatsoever. Except that word of a crackdown had percolated through the Legion of Doom. "The Mentor" voluntarily shut down "The Phoenix Project." It seemed a pity, especially as telco security employees had, in fact, shown up on Phoenix, just as he had hoped--along with the usual motley crowd of LoD heavies, hangers-on, phreaks, hackers and wannabes. There was "Sandy" Sandquist from US SPRINT security, and some guy named Henry Kluepfel, from Bellcore itself! Kluepfel had been trading friendly banter with hackers on Phoenix since January 30th (two weeks after the Martin Luther King Day Crash). The presence of such a stellar telco official seemed quite the coup for Phoenix Project. Still, Mentor could judge the climate. Atlanta in ruins, Phrack in deep trouble, something weird going on with UNIX nodes-- discretion was advisable. Phoenix Project went off-line. Kluepfel, of course, had been monitoring this LoD bulletin board for his own purposes--and those of the Chicago unit. As far back as June 1987, Kluepfel had logged on to a Texas underground board called "Phreak Klass 2600." There he'd discovered an Chicago youngster named "Shadowhawk," strutting and boasting about rifling AT&T computer files, and bragging of his ambitions to riddle AT&T's Bellcore computers with trojan horse programs. Kluepfel had passed the news to Cook in Chicago, Shadowhawk's computers had gone out the door in Secret Service custody, and Shadowhawk himself had gone to jail. Now it was Phoenix Project's turn. Phoenix Project postured about "legality" and "merely intellectual interest," but it reeked of the underground. It had Phrack on it. It had the E911 Document. It had a lot of dicey talk about breaking into systems, including some bold and reckless stuff about a supposed "decryption service" that Mentor and friends were planning to run, to help crack encrypted passwords off of hacked systems. Mentor was an adult. There was a bulletin board at his place of work, as well. Kleupfel logged onto this board, too, and discovered it to be called "Illuminati." It was run by some company called Steve Jackson Games. On March 1, 1990, the Austin crackdown went into high gear. On the morning of March 1--a Thursday--21-year-old University of Texas student "Erik Bloodaxe," co-sysop of Phoenix Project and an avowed member of the Legion of Doom, was wakened by a police revolver levelled at his head. Bloodaxe watched, jittery, as Secret Service agents appropriated his 300 baud terminal and, rifling his files, discovered his treasured source-code for Robert Morris's notorious Internet Worm. But Bloodaxe, a wily operator, had suspected that something of the like might be coming. All his best equipment had been hidden away elsewhere. The raiders took everything electronic, however, including his telephone. They were stymied by his hefty arcade-style Pac-Man game, and left it in place, as it was simply too heavy to move. Bloodaxe was not arrested. He was not charged with any crime. A good two years later, the police still had what they had taken from him, however. The Mentor was less wary. The dawn raid rousted him and his wife from bed in their underwear, and six Secret Service agents, accompanied by an Austin policeman and Henry Kluepfel himself, made a rich haul. Off went the works, into the agents' white Chevrolet minivan: an IBM PC-AT clone with 4 meg of RAM and a 120-meg hard disk; a Hewlett-Packard LaserJet II printer; a completely legitimate and highly expensive SCO-Xenix 286 operating system; Pagemaker disks and documentation; and the Microsoft Word word-processing program. Mentor's wife had her incomplete academic thesis stored on the hard-disk; that went, too, and so did the couple's telephone. As of two years later, all this property remained in police custody. Mentor remained under guard in his apartment as agents prepared to raid Steve Jackson Games. The fact that this was a business headquarters and not a private residence did not deter the agents. It was still very early; no one was at work yet. The agents prepared to break down the door, but Mentor, eavesdropping on the Secret Service walkie-talkie traffic, begged them not to do it, and offered his key to the building. The exact details of the next events are unclear. The agents would not let anyone else into the building. Their search warrant, when produced, was unsigned. Apparently they breakfasted from the local "Whataburger," as the litter from hamburgers was later found inside. They also extensively sampled a bag of jellybeans kept by an SJG employee. Someone tore a "Dukakis for President" sticker from the wall. SJG employees, diligently showing up for the day's work, were met at the door and briefly questioned by U.S. Secret Service agents. The employees watched in astonishment as agents wielding crowbars and screwdrivers emerged with captive machines. They attacked outdoor storage units with boltcutters. The agents wore blue nylon windbreakers with "SECRET SERVICE" stencilled across the back, with running-shoes and jeans. Jackson's company lost three computers, several hard-disks, hundred of floppy disks, two monitors, three modems, a laser printer, various powercords, cables, and adapters (and, oddly, a small bag of screws, bolts and nuts). The seizure of Illuminati BBS deprived SJG of all the programs, text files, and private e-mail on the board. The loss of two other SJG computers was a severe blow as well, since it caused the loss of electronically stored contracts, financial projections, address directories, mailing lists, personnel files, business correspondence, and, not least, the drafts of forthcoming games and gaming books. No one at Steve Jackson Games was arrested. No one was accused of any crime. No charges were filed. Everything appropriated was officially kept as "evidence" of crimes never specified. After the Phrack show-trial, the Steve Jackson Games scandal was the most bizarre and aggravating incident of the Hacker Crackdown of 1990. This raid by the Chicago Task Force on a science-fiction gaming publisher was to rouse a swarming host of civil liberties issues, and gave rise to an enduring controversy that was still re-complicating itself, and growing in the scope of its implications, a full two years later. The pursuit of the E911 Document stopped with the Steve Jackson Games raid. As we have seen, there were hundreds, perhaps thousands of computer users in America with the E911 Document in their possession. Theoretically, Chicago had a perfect legal right to raid any of these people, and could have legally seized the machines of anybody who subscribed to Phrack. However, there was no copy of the E911 Document on Jackson's Illuminati board. And there the Chicago raiders stopped dead; they have not raided anyone since. It might be assumed that Rich Andrews and Charlie Boykin, who had brought the E911 Document to the attention of telco security, might be spared any official suspicion. But as we have seen, the willingness to "cooperate fully" offers little, if any, assurance against federal anti-hacker prosecution. Richard Andrews found himself in deep trouble, thanks to the E911 Document. Andrews lived in Illinois, the native stomping grounds of the Chicago Task Force. On February 3 and 6, both his home and his place of work were raided by USSS. His machines went out the door, too, and he was grilled at length (though not arrested). Andrews proved to be in purportedly guilty possession of: UNIX SVR 3.2; UNIX SVR 3.1; UUCP; PMON; WWB; IWB; DWB; NROFF; KORN SHELL '88; C++; and QUEST, among other items. Andrews had received this proprietary code-- which AT&T officially valued at well over $250,000--through the UNIX network, much of it supplied to him as a personal favor by Terminus. Perhaps worse yet, Andrews admitted to returning the favor, by passing Terminus a copy of AT&T proprietary STARLAN source code. Even Charles Boykin, himself an AT&T employee, entered some very hot water. By 1990, he'd almost forgotten about the E911 problem he'd reported in September 88; in fact, since that date, he'd passed two more security alerts to Jerry Dalton, concerning matters that Boykin considered far worse than the E911 Document. But by 1990, year of the crackdown, AT&T Corporate Information Security was fed up with "Killer." This machine offered no direct income to AT&T, and was providing aid and comfort to a cloud of suspicious yokels from outside the company, some of them actively malicious toward AT&T, its property, and its corporate interests. Whatever goodwill and publicity had been won among Killer's 1,500 devoted users was considered no longer worth the security risk. On February 20, 1990, Jerry Dalton arrived in Dallas and simply unplugged the phone jacks, to the puzzled alarm of Killer's many Texan users. Killer went permanently off-line, with the loss of vast archives of programs and huge quantities of electronic mail; it was never restored to service. AT&T showed no particular regard for the "property" of these 1,500 people. Whatever "property" the users had been storing on AT&T's computer simply vanished completely. Boykin, who had himself reported the E911 problem, now found himself under a cloud of suspicion. In a weird private-security replay of the Secret Service seizures, Boykin's own home was visited by AT&T Security and his own machines were carried out the door. However, there were marked special features in the Boykin case. Boykin's disks and his personal computers were swiftly examined by his corporate employers and returned politely in just two days-- (unlike Secret Service seizures, which commonly take months or years). Boykin was not charged with any crime or wrongdoing, and he kept his job with AT&T (though he did retire from AT&T in September 1991, at the age of 52). It's interesting to note that the US Secret Service somehow failed to seize Boykin's "Killer" node and carry AT&T's own computer out the door. Nor did they raid Boykin's home. They seemed perfectly willing to take the word of AT&T Security that AT&T's employee, and AT&T's "Killer" node, were free of hacker contraband and on the up-and-up. It's digital water-under-the-bridge at this point, as Killer's 3,200 megabytes of Texan electronic community were erased in 1990, and "Killer" itself was shipped out of the state. But the experiences of Andrews and Boykin, and the users of their systems, remained side issues. They did not begin to assume the social, political, and legal importance that gathered, slowly but inexorably, around the issue of the raid on Steve Jackson Games. # We must now turn our attention to Steve Jackson Games itself, and explain what SJG was, what it really did, and how it had managed to attract this particularly odd and virulent kind of trouble. The reader may recall that this is not the first but the second time that the company has appeared in this narrative; a Steve Jackson game called GURPS was a favorite pastime of Atlanta hacker Urvile, and Urvile's science-fictional gaming notes had been mixed up promiscuously with notes about his actual computer intrusions. First, Steve Jackson Games, Inc., was NOT a publisher of "computer games." SJG published "simulation games," parlor games that were played on paper, with pencils, and dice, and printed guidebooks full of rules and statistics tables. There were no computers involved in the games themselves. When you bought a Steve Jackson Game, you did not receive any software disks. What you got was a plastic bag with some cardboard game tokens, maybe a few maps or a deck of cards. Most of their products were books. However, computers WERE deeply involved in the Steve Jackson Games business. Like almost all modern publishers, Steve Jackson and his fifteen employees used computers to write text, to keep accounts, and to run the business generally. They also used a computer to run their official bulletin board system for Steve Jackson Games, a board called Illuminati. On Illuminati, simulation gamers who happened to own computers and modems could associate, trade mail, debate the theory and practice of gaming, and keep up with the company's news and its product announcements. Illuminati was a modestly popular board, run on a small computer with limited storage, only one phone-line, and no ties to large-scale computer networks. It did, however, have hundreds of users, many of them dedicated gamers willing to call from out-of-state. Illuminati was NOT an "underground" board. It did not feature hints on computer intrusion, or "anarchy files," or illicitly posted credit card numbers, or long-distance access codes. Some of Illuminati's users, however, were members of the Legion of Doom. And so was one of Steve Jackson's senior employees--the Mentor. The Mentor wrote for Phrack, and also ran an underground board, Phoenix Project--but the Mentor was not a computer professional. The Mentor was the managing editor of Steve Jackson Games and a professional game designer by trade. These LoD members did not use Illuminati to help their HACKING activities. They used it to help their GAME-PLAYING activities--and they were even more dedicated to simulation gaming than they were to hacking. "Illuminati" got its name from a card-game that Steve Jackson himself, the company's founder and sole owner, had invented. This multi-player card-game was one of Mr Jackson's best-known, most successful, most technically innovative products. "Illuminati" was a game of paranoiac conspiracy in which various antisocial cults warred covertly to dominate the world. "Illuminati" was hilarious, and great fun to play, involving flying saucers, the CIA, the KGB, the phone companies, the Ku Klux Klan, the South American Nazis, the cocaine cartels, the Boy Scouts, and dozens of other splinter groups from the twisted depths of Mr. Jackson's professionally fervid imagination. For the uninitiated, any public discussion of the "Illuminati" card-game sounded, by turns, utterly menacing or completely insane. And then there was SJG's "Car Wars," in which souped-up armored hot-rods with rocket-launchers and heavy machine-guns did battle on the American highways of the future. The lively Car Wars discussion on the Illuminati board featured many meticulous, painstaking discussions of the effects of grenades, land-mines, flamethrowers and napalm. It sounded like hacker anarchy files run amuck. Mr Jackson and his co-workers earned their daily bread by supplying people with make-believe adventures and weird ideas. The more far-out, the better. Simulation gaming is an unusual pastime, but gamers have not generally had to beg the permission of the Secret Service to exist. Wargames and role-playing adventures are an old and honored pastime, much favored by professional military strategists. Once little-known, these games are now played by hundreds of thousands of enthusiasts throughout North America, Europe and Japan. Gaming-books, once restricted to hobby outlets, now commonly appear in chain-stores like B. Dalton's and Waldenbooks, and sell vigorously. Steve Jackson Games, Inc., of Austin, Texas, was a games company of the middle rank. In 1989, SJG grossed about a million dollars. Jackson himself had a good reputation in his industry as a talented and innovative designer of rather unconventional games, but his company was something less than a titan of the field--certainly not like the multimillion-dollar TSR Inc., or Britain's gigantic "Games Workshop." SJG's Austin headquarters was a modest two-story brick office-suite, cluttered with phones, photocopiers, fax machines and computers. It bustled with semi-organized activity and was littered with glossy promotional brochures and dog-eared science-fiction novels. Attached to the offices was a large tin-roofed warehouse piled twenty feet high with cardboard boxes of games and books. Despite the weird imaginings that went on within it, the SJG headquarters was quite a quotidian, everyday sort of place. It looked like what it was: a publishers' digs. Both "Car Wars" and "Illuminati" were well-known, popular games. But the mainstay of the Jackson organization was their Generic Universal Role-Playing System, "G.U.R.P.S." The GURPS system was considered solid and well-designed, an asset for players. But perhaps the most popular feature of the GURPS system was that it allowed gaming-masters to design scenarios that closely resembled well-known books, movies, and other works of fantasy. Jackson had licensed and adapted works from many science fiction and fantasy authors. There was GURPS Conan, GURPS Riverworld, GURPS Horseclans, GURPS Witch World, names eminently familiar to science-fiction readers. And there was GURPS Special Ops, from the world of espionage fantasy and unconventional warfare. And then there was GURPS Cyberpunk. "Cyberpunk" was a term given to certain science fiction writers who had entered the genre in the 1980s. "Cyberpunk," as the label implies, had two general distinguishing features. First, its writers had a compelling interest in information technology, an interest closely akin to science fiction's earlier fascination with space travel. And second, these writers were "punks," with all the distinguishing features that that implies: Bohemian artiness, youth run wild, an air of deliberate rebellion, funny clothes and hair, odd politics, a fondness for abrasive rock and roll; in a word, trouble. The "cyberpunk" SF writers were a small group of mostly college-educated white middle-class litterateurs, scattered through the US and Canada. Only one, Rudy Rucker, a professor of computer science in Silicon Valley, could rank with even the humblest computer hacker. But, except for Professor Rucker, the "cyberpunk" authors were not programmers or hardware experts; they considered themselves artists (as, indeed, did Professor Rucker). However, these writers all owned computers, and took an intense and public interest in the social ramifications of the information industry. The cyberpunks had a strong following among the global generation that had grown up in a world of computers, multinational networks, and cable television. Their outlook was considered somewhat morbid, cynical, and dark, but then again, so was the outlook of their generational peers. As that generation matured and increased in strength and influence, so did the cyberpunks. As science-fiction writers went, they were doing fairly well for themselves. By the late 1980s, their work had attracted attention from gaming companies, including Steve Jackson Games, which was planning a cyberpunk simulation for the flourishing GURPS gaming-system. The time seemed ripe for such a product, which had already been proven in the marketplace. The first games- company out of the gate, with a product boldly called "Cyberpunk" in defiance of possible infringement-of-copyright suits, had been an upstart group called R. Talsorian. Talsorian's Cyberpunk was a fairly decent game, but the mechanics of the simulation system left a lot to be desired. Commercially, however, the game did very well. The next cyberpunk game had been the even more successful Shadowrun by FASA Corporation. The mechanics of this game were fine, but the scenario was rendered moronic by sappy fantasy elements like elves, trolls, wizards, and dragons--all highly ideologically-incorrect, according to the hard-edged, high-tech standards of cyberpunk science fiction. Other game designers were champing at the bit. Prominent among them was the Mentor, a gentleman who, like most of his friends in the Legion of Doom, was quite the cyberpunk devotee. Mentor reasoned that the time had come for a REAL cyberpunk gaming-book--one that the princes of computer-mischief in the Legion of Doom could play without laughing themselves sick. This book, GURPS Cyberpunk, would reek of culturally on-line authenticity. Mentor was particularly well-qualified for this task. Naturally, he knew far more about computer-intrusion and digital skullduggery than any previously published cyberpunk author. Not only that, but he was good at his work. A vivid imagination, combined with an instinctive feeling for the working of systems and, especially, the loopholes within them, are excellent qualities for a professional game designer. By March 1st, GURPS Cyberpunk was almost complete, ready to print and ship. Steve Jackson expected vigorous sales for this item, which, he hoped, would keep the company financially afloat for several months. GURPS Cyberpunk, like the other GURPS "modules," was not a "game" like a Monopoly set, but a BOOK: a bound paperback book the size of a glossy magazine, with a slick color cover, and pages full of text, illustrations, tables and footnotes. It was advertised as a game, and was used as an aid to game-playing, but it was a book, with an ISBN number, published in Texas, copyrighted, and sold in bookstores. And now, that book, stored on a computer, had gone out the door in the custody of the Secret Service. The day after the raid, Steve Jackson visited the local Secret Service headquarters with a lawyer in tow. There he confronted Tim Foley (still in Austin at that time) and demanded his book back. But there was trouble. GURPS Cyberpunk, alleged a Secret Service agent to astonished businessman Steve Jackson, was "a manual for computer crime." "It's science fiction," Jackson said. "No, this is real." This statement was repeated several times, by several agents. Jackson's ominously accurate game had passed from pure, obscure, small-scale fantasy into the impure, highly publicized, large-scale fantasy of the Hacker Crackdown. No mention was made of the real reason for the search. According to their search warrant, the raiders had expected to find the E911 Document stored on Jackson's bulletin board system. But that warrant was sealed; a procedure that most law enforcement agencies will use only when lives are demonstrably in danger. The raiders' true motives were not discovered until the Jackson search-warrant was unsealed by his lawyers, many months later. The Secret Service, and the Chicago Computer Fraud and Abuse Task Force, said absolutely nothing to Steve Jackson about any threat to the police 911 System. They said nothing about the Atlanta Three, nothing about Phrack or Knight Lightning, nothing about Terminus. Jackson was left to believe that his computers had been seized because he intended to publish a science fiction book that law enforcement considered too dangerous to see print. This misconception was repeated again and again, for months, to an ever-widening public audience. It was not the truth of the case; but as months passed, and this misconception was publicly printed again and again, it became one of the few publicly known "facts" about the mysterious Hacker Crackdown. The Secret Service had seized a computer to stop the publication of a cyberpunk science fiction book. The second section of this book, "The Digital Underground," is almost finished now. We have become acquainted with all the major figures of this case who actually belong to the underground milieu of computer intrusion. We have some idea of their history, their motives, their general modus operandi. We now know, I hope, who they are, where they came from, and more or less what they want. In the next section of this book, "Law and Order," we will leave this milieu and directly enter the world of America's computer-crime police. At this point, however, I have another figure to introduce: myself. My name is Bruce Sterling. I live in Austin, Texas, where I am a science fiction writer by trade: specifically, a CYBERPUNK science fiction writer. Like my "cyberpunk" colleagues in the U.S. and Canada, I've never been entirely happy with this literary label-- especially after it became a synonym for computer criminal. But I did once edit a book of stories by my colleagues, called Mirrorshades: the Cyberpunk Anthology, and I've long been a writer of literary-critical cyberpunk manifestos. I am not a "hacker" of any description, though I do have readers in the digital underground. When the Steve Jackson Games seizure occurred, I naturally took an intense interest. If "cyberpunk" books were being banned by federal police in my own home town, I reasonably wondered whether I myself might be next. Would my computer be seized by the Secret Service? At the time, I was in possession of an aging Apple IIe without so much as a hard disk. If I were to be raided as an author of computer-crime manuals, the loss of my feeble word-processor would likely provoke more snickers than sympathy. I'd known Steve Jackson for many years. We knew one another as colleagues, for we frequented the same local science-fiction conventions. I'd played Jackson games, and recognized his cleverness; but he certainly had never struck me as a potential mastermind of computer crime. I also knew a little about computer bulletin-board systems. In the mid-1980s I had taken an active role in an Austin board called "SMOF-BBS," one of the first boards dedicated to science fiction. I had a modem, and on occasion I'd logged on to Illuminati, which always looked entertainly wacky, but certainly harmless enough. At the time of the Jackson seizure, I had no experience whatsoever with underground boards. But I knew that no one on Illuminati talked about breaking into systems illegally, or about robbing phone companies. Illuminati didn't even offer pirated computer games. Steve Jackson, like many creative artists, was markedly touchy about theft of intellectual property. It seemed to me that Jackson was either seriously suspected of some crime--in which case, he would be charged soon, and would have his day in court--or else he was innocent, in which case the Secret Service would quickly return his equipment, and everyone would have a good laugh. I rather expected the good laugh. The situation was not without its comic side. The raid, known as the "Cyberpunk Bust" in the science fiction community, was winning a great deal of free national publicity both for Jackson himself and the "cyberpunk" science fiction writers generally. Besides, science fiction people are used to being misinterpreted. Science fiction is a colorful, disreputable, slipshod occupation, full of unlikely oddballs, which, of course, is why we like it. Weirdness can be an occupational hazard in our field. People who wear Halloween costumes are sometimes mistaken for monsters. Once upon a time--back in 1939, in New York City-- science fiction and the U.S. Secret Service collided in a comic case of mistaken identity. This weird incident involved a literary group quite famous in science fiction, known as "the Futurians," whose membership included such future genre greats as Isaac Asimov, Frederik Pohl, and Damon Knight. The Futurians were every bit as offbeat and wacky as any of their spiritual descendants, including the cyberpunks, and were given to communal living, spontaneous group renditions of light opera, and midnight fencing exhibitions on the lawn. The Futurians didn't have bulletin board systems, but they did have the technological equivalent in 1939--mimeographs and a private printing press. These were in steady use, producing a stream of science-fiction fan magazines, literary manifestos, and weird articles, which were picked up in ink-sticky bundles by a succession of strange, gangly, spotty young men in fedoras and overcoats. The neighbors grew alarmed at the antics of the Futurians and reported them to the Secret Service as suspected counterfeiters. In the winter of 1939, a squad of USSS agents with drawn guns burst into "Futurian House," prepared to confiscate the forged currency and illicit printing presses. There they discovered a slumbering science fiction fan named George Hahn, a guest of the Futurian commune who had just arrived in New York. George Hahn managed to explain himself and his group, and the Secret Service agents left the Futurians in peace henceforth. (Alas, Hahn died in 1991, just before I had discovered this astonishing historical parallel, and just before I could interview him for this book.) But the Jackson case did not come to a swift and comic end. No quick answers came his way, or mine; no swift reassurances that all was right in the digital world, that matters were well in hand after all. Quite the opposite. In my alternate role as a sometime pop-science journalist, I interviewed Jackson and his staff for an article in a British magazine. The strange details of the raid left me more concerned than ever. Without its computers, the company had been financially and operationally crippled. Half the SJG workforce, a group of entirely innocent people, had been sorrowfully fired, deprived of their livelihoods by the seizure. It began to dawn on me that authors--American writers--might well have their computers seized, under sealed warrants, without any criminal charge; and that, as Steve Jackson had discovered, there was no immediate recourse for this. This was no joke; this wasn't science fiction; this was real. I determined to put science fiction aside until I had discovered what had happened and where this trouble had come from. It was time to enter the purportedly real world of electronic free expression and computer crime. Hence, this book. Hence, the world of the telcos; and the world of the digital underground; and next, the world of the police. PART THREE: LAW AND ORDER Of the various anti-hacker activities of 1990, "Operation Sundevil" had by far the highest public profile. The sweeping, nationwide computer seizures of May 8, 1990 were unprecedented in scope and highly, if rather selectively, publicized. Unlike the efforts of the Chicago Computer Fraud and Abuse Task Force, "Operation Sundevil" was not intended to combat "hacking" in the sense of computer intrusion or sophisticated raids on telco switching stations. Nor did it have anything to do with hacker misdeeds with AT&T's software, or with Southern Bell's proprietary documents. Instead, "Operation Sundevil" was a crackdown on those traditional scourges of the digital underground: credit-card theft and telephone code abuse. The ambitious activities out of Chicago, and the somewhat lesser-known but vigorous anti-hacker actions of the New York State Police in 1990, were never a part of "Operation Sundevil" per se, which was based in Arizona. Nevertheless, after the spectacular May 8 raids, the public, misled by police secrecy, hacker panic, and a puzzled national press-corps, conflated all aspects of the nationwide crackdown in 1990 under the blanket term "Operation Sundevil." "Sundevil" is still the best-known synonym for the crackdown of 1990. But the Arizona organizers of "Sundevil" did not really deserve this reputation--any more, for instance, than all hackers deserve a reputation as "hackers." There was some justice in this confused perception, though. For one thing, the confusion was abetted by the Washington office of the Secret Service, who responded to Freedom of Information Act requests on "Operation Sundevil" by referring investigators to the publicly known cases of Knight Lightning and the Atlanta Three. And "Sundevil" was certainly the largest aspect of the Crackdown, the most deliberate and the best-organized. As a crackdown on electronic fraud, "Sundevil" lacked the frantic pace of the war on the Legion of Doom; on the contrary, Sundevil's targets were picked out with cool deliberation over an elaborate investigation lasting two full years. And once again the targets were bulletin board systems. Boards can be powerful aids to organized fraud. Underground boards carry lively, extensive, detailed, and often quite flagrant "discussions" of lawbreaking techniques and lawbreaking activities. "Discussing" crime in the abstract, or "discussing" the particulars of criminal cases, is not illegal--but there are stern state and federal laws against coldbloodedly conspiring in groups in order to commit crimes. In the eyes of police, people who actively conspire to break the law are not regarded as "clubs," "debating salons," "users' groups," or "free speech advocates." Rather, such people tend to find themselves formally indicted by prosecutors as "gangs," "racketeers," "corrupt organizations" and "organized crime figures." What's more, the illicit data contained on outlaw boards goes well beyond mere acts of speech and/or possible criminal conspiracy. As we have seen, it was common practice in the digital underground to post purloined telephone codes on boards, for any phreak or hacker who cared to abuse them. Is posting digital booty of this sort supposed to be protected by the First Amendment? Hardly--though the issue, like most issues in cyberspace, is not entirely resolved. Some theorists argue that to merely RECITE a number publicly is not illegal--only its USE is illegal. But anti-hacker police point out that magazines and newspapers (more traditional forms of free expression) never publish stolen telephone codes (even though this might well raise their circulation). Stolen credit card numbers, being riskier and more valuable, were less often publicly posted on boards--but there is no question that some underground boards carried "carding" traffic, generally exchanged through private mail. Underground boards also carried handy programs for "scanning" telephone codes and raiding credit card companies, as well as the usual obnoxious galaxy of pirated software, cracked passwords, blue-box schematics, intrusion manuals, anarchy files, porn files, and so forth. But besides their nuisance potential for the spread of illicit knowledge, bulletin boards have another vitally interesting aspect for the professional investigator. Bulletin boards are cram-full of EVIDENCE. All that busy trading of electronic mail, all those hacker boasts, brags and struts, even the stolen codes and cards, can be neat, electronic, real-time recordings of criminal activity. As an investigator, when you seize a pirate board, you have scored a coup as effective as tapping phones or intercepting mail. However, you have not actually tapped a phone or intercepted a letter. The rules of evidence regarding phone-taps and mail interceptions are old, stern and well-understood by police, prosecutors and defense attorneys alike. The rules of evidence regarding boards are new, waffling, and understood by nobody at all. Sundevil was the largest crackdown on boards in world history. On May 7, 8, and 9, 1990, about forty-two computer systems were seized. Of those forty-two computers, about twenty-five actually were running boards. (The vagueness of this estimate is attributable to the vagueness of (a) what a "computer system" is, and (b) what it actually means to "run a board" with one--or with two computers, or with three.) About twenty-five boards vanished into police custody in May 1990. As we have seen, there are an estimated 30,000 boards in America today. If we assume that one board in a hundred is up to no good with codes and cards (which rather flatters the honesty of the board-using community), then that would leave 2,975 outlaw boards untouched by Sundevil. Sundevil seized about one tenth of one percent of all computer bulletin boards in America. Seen objectively, this is something less than a comprehensive assault. In 1990, Sundevil's organizers-- the team at the Phoenix Secret Service office, and the Arizona Attorney General's office-- had a list of at least THREE HUNDRED boards that they considered fully deserving of search and seizure warrants. The twenty-five boards actually seized were merely among the most obvious and egregious of this much larger list of candidates. All these boards had been examined beforehand--either by informants, who had passed printouts to the Secret Service, or by Secret Service agents themselves, who not only come equipped with modems but know how to use them. There were a number of motives for Sundevil. First, it offered a chance to get ahead of the curve on wire-fraud crimes. Tracking back credit-card ripoffs to their perpetrators can be appallingly difficult. If these miscreants have any kind of electronic sophistication, they can snarl their tracks through the phone network into a mind-boggling, untraceable mess, while still managing to "reach out and rob someone." Boards, however, full of brags and boasts, codes and cards, offer evidence in the handy congealed form. Seizures themselves--the mere physical removal of machines-- tends to take the pressure off. During Sundevil, a large number of code kids, warez d00dz, and credit card thieves would be deprived of those boards--their means of community and conspiracy--in one swift blow. As for the sysops themselves (commonly among the boldest offenders) they would be directly stripped of their computer equipment, and rendered digitally mute and blind. And this aspect of Sundevil was carried out with great success. Sundevil seems to have been a complete tactical surprise-- unlike the fragmentary and continuing seizures of the war on the Legion of Doom, Sundevil was precisely timed and utterly overwhelming. At least forty "computers" were seized during May 7, 8 and 9, 1990, in Cincinnati, Detroit, Los Angeles, Miami, Newark, Phoenix, Tucson, Richmond, San Diego, San Jose, Pittsburgh and San Francisco. Some cities saw multiple raids, such as the five separate raids in the New York City environs. Plano, Texas (essentially a suburb of the Dallas/Fort Worth metroplex, and a hub of the telecommunications industry) saw four computer seizures. Chicago, ever in the forefront, saw its own local Sundevil raid, briskly carried out by Secret Service agents Timothy Foley and Barbara Golden. Many of these raids occurred, not in the cities proper, but in associated white-middle class suburbs--places like Mount Lebanon, Pennsylvania and Clark Lake, Michigan. There were a few raids on offices; most took place in people's homes, the classic hacker basements and bedrooms. The Sundevil raids were searches and seizures, not a group of mass arrests. There were only four arrests during Sundevil. "Tony the Trashman," a longtime teenage bete noire of the Arizona Racketeering unit, was arrested in Tucson on May 9. "Dr. Ripco," sysop of an outlaw board with the misfortune to exist in Chicago itself, was also arrested-- on illegal weapons charges. Local units also arrested a 19-year-old female phone phreak named "Electra" in Pennsylvania, and a male juvenile in California. Federal agents however were not seeking arrests, but computers. Hackers are generally not indicted (if at all) until the evidence in their seized computers is evaluated--a process that can take weeks, months--even years. When hackers are arrested on the spot, it's generally an arrest for other reasons. Drugs and/or illegal weapons show up in a good third of anti-hacker computer seizures (though not during Sundevil). That scofflaw teenage hackers (or their parents) should have marijuana in their homes is probably not a shocking revelation, but the surprisingly common presence of illegal firearms in hacker dens is a bit disquieting. A Personal Computer can be a great equalizer for the techno-cowboy-- much like that more traditional American "Great Equalizer," the Personal Sixgun. Maybe it's not all that surprising that some guy obsessed with power through illicit technology would also have a few illicit high-velocity-impact devices around. An element of the digital underground particularly dotes on those "anarchy philes," and this element tends to shade into the crackpot milieu of survivalists, gun-nuts, anarcho-leftists and the ultra-libertarian right-wing. This is not to say that hacker raids to date have uncovered any major crack-dens or illegal arsenals; but Secret Service agents do not regard "hackers" as "just kids." They regard hackers as unpredictable people, bright and slippery. It doesn't help matters that the hacker himself has been "hiding behind his keyboard" all this time. Commonly, police have no idea what he looks like. This makes him an unknown quantity, someone best treated with proper caution. To date, no hacker has come out shooting, though they do sometimes brag on boards that they will do just that. Threats of this sort are taken seriously. Secret Service hacker raids tend to be swift, comprehensive, well-manned (even over-manned); and agents generally burst through every door in the home at once, sometimes with drawn guns. Any potential resistance is swiftly quelled. Hacker raids are usually raids on people's homes. It can be a very dangerous business to raid an American home; people can panic when strangers invade their sanctum. Statistically speaking, the most dangerous thing a policeman can do is to enter someone's home. (The second most dangerous thing is to stop a car in traffic.) People have guns in their homes. More cops are hurt in homes than are ever hurt in biker bars or massage parlors. But in any case, no one was hurt during Sundevil, or indeed during any part of the Hacker Crackdown. Nor were there any allegations of any physical mistreatment of a suspect. Guns were pointed, interrogations were sharp and prolonged; but no one in 1990 claimed any act of brutality by any crackdown raider. In addition to the forty or so computers, Sundevil reaped floppy disks in particularly great abundance--an estimated 23,000 of them, which naturally included every manner of illegitimate data: pirated games, stolen codes, hot credit card numbers, the complete text and software of entire pirate bulletin-boards. These floppy disks, which remain in police custody today, offer a gigantic, almost embarrassingly rich source of possible criminal indictments. These 23,000 floppy disks also include a thus-far unknown quantity of legitimate computer games, legitimate software, purportedly "private" mail from boards, business records, and personal correspondence of all kinds. Standard computer-crime search warrants lay great emphasis on seizing written documents as well as computers--specifically including photocopies, computer printouts, telephone bills, address books, logs, notes, memoranda and correspondence. In practice, this has meant that diaries, gaming magazines, software documentation, nonfiction books on hacking and computer security, sometimes even science fiction novels, have all vanished out the door in police custody. A wide variety of electronic items have been known to vanish as well, including telephones, televisions, answering machines, Sony Walkmans, desktop printers, compact disks, and audiotapes. No fewer than 150 members of the Secret Service were sent into the field during Sundevil. They were commonly accompanied by squads of local and/or state police. Most of these officers-- especially the locals--had never been on an anti-hacker raid before. (This was one good reason, in fact, why so many of them were invited along in the first place.) Also, the presence of a uniformed police officer assures the raidees that the people entering their homes are, in fact, police. Secret Service agents wear plain clothes. So do the telco security experts who commonly accompany the Secret Service on raids (and who make no particular effort to identify themselves as mere employees of telephone companies). A typical hacker raid goes something like this. First, police storm in rapidly, through every entrance, with overwhelming force, in the assumption that this tactic will keep casualties to a minimum. Second, possible suspects are immediately removed from the vicinity of any and all computer systems, so that they will have no chance to purge or destroy computer evidence. Suspects are herded into a room without computers, commonly the living room, and kept under guard-- not ARMED guard, for the guns are swiftly holstered, but under guard nevertheless. They are presented with the search warrant and warned that anything they say may be held against them. Commonly they have a great deal to say, especially if they are unsuspecting parents. Somewhere in the house is the "hot spot"--a computer tied to a phone line (possibly several computers and several phones). Commonly it's a teenager's bedroom, but it can be anywhere in the house; there may be several such rooms. This "hot spot" is put in charge of a two-agent team, the "finder" and the "recorder." The "finder" is computer-trained, commonly the case agent who has actually obtained the search warrant from a judge. He or she understands what is being sought, and actually carries out the seizures: unplugs machines, opens drawers, desks, files, floppy-disk containers, etc. The "recorder" photographs all the equipment, just as it stands--especially the tangle of wired connections in the back, which can otherwise be a real nightmare to restore. The recorder will also commonly photograph every room in the house, lest some wily criminal claim that the police had robbed him during the search. Some recorders carry videocams or tape recorders; however, it's more common for the recorder to simply take written notes. Objects are described and numbered as the finder seizes them, generally on standard preprinted police inventory forms. Even Secret Service agents were not, and are not, expert computer users. They have not made, and do not make, judgements on the fly about potential threats posed by various forms of equipment. They may exercise discretion; they may leave Dad his computer, for instance, but they don't HAVE to. Standard computer-crime search warrants, which date back to the early 80s, use a sweeping language that targets computers, most anything attached to a computer, most anything used to operate a computer--most anything that remotely resembles a computer--plus most any and all written documents surrounding it. Computer-crime investigators have strongly urged agents to seize the works. In this sense, Operation Sundevil appears to have been a complete success. Boards went down all over America, and were shipped en masse to the computer investigation lab of the Secret Service, in Washington DC, along with the 23,000 floppy disks and unknown quantities of printed material. But the seizure of twenty-five boards, and the multi-megabyte mountains of possibly useful evidence contained in these boards (and in their owners' other computers, also out the door), were far from the only motives for Operation Sundevil. An unprecedented action of great ambition and size, Sundevil's motives can only be described as political. It was a public-relations effort, meant to pass certain messages, meant to make certain situations clear: both in the mind of the general public, and in the minds of various constituencies of the electronic community. First --and this motivation was vital--a "message" would be sent from law enforcement to the digital underground. This very message was recited in so many words by Garry M. Jenkins, the Assistant Director of the US Secret Service, at the Sundevil press conference in Phoenix on May 9, 1990, immediately after the raids. In brief, hackers were mistaken in their foolish belief that they could hide behind the "relative anonymity of their computer terminals." On the contrary, they should fully understand that state and federal cops were actively patrolling the beat in cyberspace--that they were on the watch everywhere, even in those sleazy and secretive dens of cybernetic vice, the underground boards. This is not an unusual message for police to publicly convey to crooks. The message is a standard message; only the context is new. In this respect, the Sundevil raids were the digital equivalent of the standard vice-squad crackdown on massage parlors, porno bookstores, head-shops, or floating crap-games. There may be few or no arrests in a raid of this sort; no convictions, no trials, no interrogations. In cases of this sort, police may well walk out the door with many pounds of sleazy magazines, X-rated videotapes, sex toys, gambling equipment, baggies of marijuana. . . . Of course, if something truly horrendous is discovered by the raiders, there will be arrests and prosecutions. Far more likely, however, there will simply be a brief but sharp disruption of the closed and secretive world of the nogoodniks. There will be "street hassle." "Heat." "Deterrence." And, of course, the immediate loss of the seized goods. It is very unlikely that any of this seized material will ever be returned. Whether charged or not, whether convicted or not, the perpetrators will almost surely lack the nerve ever to ask for this stuff to be given back. Arrests and trials--putting people in jail--may involve all kinds of formal legalities; but dealing with the justice system is far from the only task of police. Police do not simply arrest people. They don't simply put people in jail. That is not how the police perceive their jobs. Police "protect and serve." Police "keep the peace," they "keep public order." Like other forms of public relations, keeping public order is not an exact science. Keeping public order is something of an art-form. If a group of tough-looking teenage hoodlums was loitering on a street-corner, no one would be surprised to see a street-cop arrive and sternly order them to "break it up." On the contrary, the surprise would come if one of these ne'er-do-wells stepped briskly into a phone-booth, called a civil rights lawyer, and instituted a civil suit in defense of his Constitutional rights of free speech and free assembly. But something much along this line was one of the many anomolous outcomes of the Hacker Crackdown. Sundevil also carried useful "messages" for other constituents of the electronic community. These messages may not have been read aloud from the Phoenix podium in front of the press corps, but there was little mistaking their meaning. There was a message of reassurance for the primary victims of coding and carding: the telcos, and the credit companies. Sundevil was greeted with joy by the security officers of the electronic business community. After years of high-tech harassment and spiralling revenue losses, their complaints of rampant outlawry were being taken seriously by law enforcement. No more head-scratching or dismissive shrugs; no more feeble excuses about "lack of computer-trained officers" or the low priority of "victimless" white-collar telecommunication crimes. Computer-crime experts have long believed that computer-related offenses are drastically under-reported. They regard this as a major open scandal of their field. Some victims are reluctant to come forth, because they believe that police and prosecutors are not computer-literate, and can and will do nothing. Others are embarrassed by their vulnerabilities, and will take strong measures to avoid any publicity; this is especially true of banks, who fear a loss of investor confidence should an embezzlement-case or wire-fraud surface. And some victims are so helplessly confused by their own high technology that they never even realize that a crime has occurred--even when they have been fleeced to the bone. The results of this situation can be dire. Criminals escape apprehension and punishment. The computer-crime units that do exist, can't get work. The true scope of computer-crime: its size, its real nature, the scope of its threats, and the legal remedies for it-- all remain obscured. Another problem is very little publicized, but it is a cause of genuine concern. Where there is persistent crime, but no effective police protection, then vigilantism can result. Telcos, banks, credit companies, the major corporations who maintain extensive computer networks vulnerable to hacking --these organizations are powerful, wealthy, and politically influential. They are disinclined to be pushed around by crooks (or by most anyone else, for that matter). They often maintain well-organized private security forces, commonly run by experienced veterans of military and police units, who have left public service for the greener pastures of the private sector. For police, the corporate security manager can be a powerful ally; but if this gentleman finds no allies in the police, and the pressure is on from his board-of-directors, he may quietly take certain matters into his own hands. Nor is there any lack of disposable hired-help in the corporate security business. Private security agencies-- the `security business' generally--grew explosively in the 1980s. Today there are spooky gumshoed armies of "security consultants," "rent-a- cops," "private eyes," "outside experts"--every manner of shady operator who retails in "results" and discretion. Or course, many of these gentlemen and ladies may be paragons of professional and moral rectitude. But as anyone who has read a hard-boiled detective novel knows, police tend to be less than fond of this sort of private-sector competition. Companies in search of computer-security have even been known to hire hackers. Police shudder at this prospect. Police treasure good relations with the business community. Rarely will you see a policeman so indiscreet as to allege publicly that some major employer in his state or city has succumbed to paranoia and gone off the rails. Nevertheless, police --and computer police in particular--are aware of this possibility. Computer-crime police can and do spend up to half of their business hours just doing public relations: seminars, "dog and pony shows," sometimes with parents' groups or computer users, but generally with their core audience: the likely victims of hacking crimes. These, of course, are telcos, credit card companies and large computer-equipped corporations. The police strongly urge these people, as good citizens, to report offenses and press criminal charges; they pass the message that there is someone in authority who cares, understands, and, best of all, will take useful action should a computer-crime occur. But reassuring talk is cheap. Sundevil offered action. The final message of Sundevil was intended for internal consumption by law enforcement. Sundevil was offered as proof that the community of American computer-crime police had come of age. Sundevil was proof that enormous things like Sundevil itself could now be accomplished. Sundevil was proof that the Secret Service and its local law-enforcement allies could act like a well-oiled machine--(despite the hampering use of those scrambled phones). It was also proof that the Arizona Organized Crime and Racketeering Unit--the sparkplug of Sundevil--ranked with the best in the world in ambition, organization, and sheer conceptual daring. And, as a final fillip, Sundevil was a message from the Secret Service to their longtime rivals in the Federal Bureau of Investigation. By Congressional fiat, both USSS and FBI formally share jurisdiction over federal computer-crimebusting activities. Neither of these groups has ever been remotely happy with this muddled situation. It seems to suggest that Congress cannot make up its mind as to which of these groups is better qualified. And there is scarcely a G-man or a Special Agent anywhere without a very firm opinion on that topic. # For the neophyte, one of the most puzzling aspects of the crackdown on hackers is why the United States Secret Service has anything at all to do with this matter. The Secret Service is best known for its primary public role: its agents protect the President of the United States. They also guard the President's family, the Vice President and his family, former Presidents, and Presidential candidates. They sometimes guard foreign dignitaries who are visiting the United States, especially foreign heads of state, and have been known to accompany American officials on diplomatic missions overseas. Special Agents of the Secret Service don't wear uniforms, but the Secret Service also has two uniformed police agencies. There's the former White House Police (now known as the Secret Service Uniformed Division, since they currently guard foreign embassies in Washington, as well as the White House itself). And there's the uniformed Treasury Police Force. The Secret Service has been charged by Congress with a number of little-known duties. They guard the precious metals in Treasury vaults. They guard the most valuable historical documents of the United States: originals of the Constitution, the Declaration of Independence, Lincoln's Second Inaugural Address, an American-owned copy of the Magna Carta, and so forth. Once they were assigned to guard the Mona Lisa, on her American tour in the 1960s. The entire Secret Service is a division of the Treasury Department. Secret Service Special Agents (there are about 1,900 of them) are bodyguards for the President et al, but they all work for the Treasury. And the Treasury (through its divisions of the U.S. Mint and the Bureau of Engraving and Printing) prints the nation's money. As Treasury police, the Secret Service guards the nation's currency; it is the only federal law enforcement agency with direct jurisdiction over counterfeiting and forgery. It analyzes documents for authenticity, and its fight against fake cash is still quite lively (especially since the skilled counterfeiters of Medellin, Columbia have gotten into the act). Government checks, bonds, and other obligations, which exist in untold millions and are worth untold billions, are common targets for forgery, which the Secret Service also battles. It even handles forgery of postage stamps. But cash is fading in importance today as money has become electronic. As necessity beckoned, the Secret Service moved from fighting the counterfeiting of paper currency and the forging of checks, to the protection of funds transferred by wire. From wire-fraud, it was a simple skip-and-jump to what is formally known as "access device fraud." Congress granted the Secret Service the authority to investigate "access device fraud" under Title 18 of the United States Code (U.S.C. Section 1029). The term "access device" seems intuitively simple. It's some kind of high-tech gizmo you use to get money with. It makes good sense to put this sort of thing in the charge of counterfeiting and wire-fraud experts. However, in Section 1029, the term "access device" is very generously defined. An access device is: "any card, plate, code, account number, or other means of account access that can be used, alone or in conjunction with another access device, to obtain money, goods, services, or any other thing of value, or that can be used to initiate a transfer of funds." "Access device" can therefore be construed to include credit cards themselves (a popular forgery item nowadays). It also includes credit card account NUMBERS, those standards of the digital underground. The same goes for telephone charge cards (an increasingly popular item with telcos, who are tired of being robbed of pocket change by phone-booth thieves). And also telephone access CODES, those OTHER standards of the digital underground. (Stolen telephone codes may not "obtain money," but they certainly do obtain valuable "services," which is specifically forbidden by Section 1029.) We can now see that Section 1029 already pits the United States Secret Service directly against the digital underground, without any mention at all of the word "computer." Standard phreaking devices, like "blue boxes," used to steal phone service from old-fashioned mechanical switches, are unquestionably "counterfeit access devices." Thanks to Sec.1029, it is not only illegal to USE counterfeit access devices, but it is even illegal to BUILD them. "Producing," "designing" "duplicating" or "assembling" blue boxes are all federal crimes today, and if you do this, the Secret Service has been charged by Congress to come after you. Automatic Teller Machines, which replicated all over America during the 1980s, are definitely "access devices," too, and an attempt to tamper with their punch-in codes and plastic bank cards falls directly under Sec. 1029. Section 1029 is remarkably elastic. Suppose you find a computer password in somebody's trash. That password might be a "code"--it's certainly a "means of account access." Now suppose you log on to a computer and copy some software for yourself. You've certainly obtained "service" (computer service) and a "thing of value" (the software). Suppose you tell a dozen friends about your swiped password, and let them use it, too. Now you're "trafficking in unauthorized access devices." And when the Prophet, a member of the Legion of Doom, passed a stolen telephone company document to Knight Lightning at Phrack magazine, they were both charged under Sec. 1029! There are two limitations on Section 1029. First, the offense must "affect interstate or foreign commerce" in order to become a matter of federal jurisdiction. The term "affecting commerce" is not well defined; but you may take it as a given that the Secret Service can take an interest if you've done most anything that happens to cross a state line. State and local police can be touchy about their jurisdictions, and can sometimes be mulish when the feds show up. But when it comes to computer-crime, the local police are pathetically grateful for federal help--in fact they complain that they can't get enough of it. If you're stealing long-distance service, you're almost certainly crossing state lines, and you're definitely "affecting the interstate commerce" of the telcos. And if you're abusing credit cards by ordering stuff out of glossy catalogs from, say, Vermont, you're in for it. The second limitation is money. As a rule, the feds don't pursue penny-ante offenders. Federal judges will dismiss cases that appear to waste their time. Federal crimes must be serious; Section 1029 specifies a minimum loss of a thousand dollars. We now come to the very next section of Title 18, which is Section 1030, "Fraud and related activity in connection with computers." This statute gives the Secret Service direct jurisdiction over acts of computer intrusion. On the face of it, the Secret Service would now seem to command the field. Section 1030, however, is nowhere near so ductile as Section 1029. The first annoyance is Section 1030(d), which reads: "(d) The United States Secret Service shall, IN ADDITION TO ANY OTHER AGENCY HAVING SUCH AUTHORITY, have the authority to investigate offenses under this section. Such authority of the United States Secret Service shall be exercised in accordance with an agreement which shall be entered into by the Secretary of the Treasury AND THE ATTORNEY GENERAL." (Author's italics.) [Represented by capitals.] The Secretary of the Treasury is the titular head of the Secret Service, while the Attorney General is in charge of the FBI. In Section (d), Congress shrugged off responsibility for the computer-crime turf-battle between the Service and the Bureau, and made them fight it out all by themselves. The result was a rather dire one for the Secret Service, for the FBI ended up with exclusive jurisdiction over computer break-ins having to do with national security, foreign espionage, federally insured banks, and U.S. military bases, while retaining joint jurisdiction over all the other computer intrusions. Essentially, when it comes to Section 1030, the FBI not only gets the real glamor stuff for itself, but can peer over the shoulder of the Secret Service and barge in to meddle whenever it suits them. The second problem has to do with the dicey term "Federal interest computer." Section 1030(a)(2) makes it illegal to "access a computer without authorization" if that computer belongs to a financial institution or an issuer of credit cards (fraud cases, in other words). Congress was quite willing to give the Secret Service jurisdiction over money-transferring computers, but Congress balked at letting them investigate any and all computer intrusions. Instead, the USSS had to settle for the money machines and the "Federal interest computers." A "Federal interest computer" is a computer which the government itself owns, or is using. Large networks of interstate computers, linked over state lines, are also considered to be of "Federal interest." (This notion of "Federal interest" is legally rather foggy and has never been clearly defined in the courts. The Secret Service has never yet had its hand slapped for investigating computer break-ins that were NOT of "Federal interest," but conceivably someday this might happen.) So the Secret Service's authority over "unauthorized access" to computers covers a lot of territory, but by no means the whole ball of cyberspatial wax. If you are, for instance, a LOCAL computer retailer, or the owner of a LOCAL bulletin board system, then a malicious LOCAL intruder can break in, crash your system, trash your files and scatter viruses, and the U.S. Secret Service cannot do a single thing about it. At least, it can't do anything DIRECTLY. But the Secret Service will do plenty to help the local people who can. The FBI may have dealt itself an ace off the bottom of the deck when it comes to Section 1030; but that's not the whole story; that's not the street. What's Congress thinks is one thing, and Congress has been known to change its mind. The REAL turf-struggle is out there in the streets where it's happening. If you're a local street-cop with a computer problem, the Secret Service wants you to know where you can find the real expertise. While the Bureau crowd are off having their favorite shoes polished--(wing-tips)--and making derisive fun of the Service's favorite shoes--("pansy-ass tassels")-- the tassel-toting Secret Service has a crew of ready-and-able hacker-trackers installed in the capital of every state in the Union. Need advice? They'll give you advice, or at least point you in the right direction. Need training? They can see to that, too. If you're a local cop and you call in the FBI, the FBI (as is widely and slanderously rumored) will order you around like a coolie, take all the credit for your busts, and mop up every possible scrap of reflected glory. The Secret Service, on the other hand, doesn't brag a lot. They're the quiet types. VERY quiet. Very cool. Efficient. High-tech. Mirrorshades, icy stares, radio ear-plugs, an Uzi machine-pistol tucked somewhere in that well-cut jacket. American samurai, sworn to give their lives to protect our President. "The granite agents." Trained in martial arts, absolutely fearless. Every single one of 'em has a top-secret security clearance. Something goes a little wrong, you're not gonna hear any whining and moaning and political buck-passing out of these guys. The facade of the granite agent is not, of course, the reality. Secret Service agents are human beings. And the real glory in Service work is not in battling computer crime--not yet, anyway--but in protecting the President. The real glamour of Secret Service work is in the White House Detail. If you're at the President's side, then the kids and the wife see you on television; you rub shoulders with the most powerful people in the world. That's the real heart of Service work, the number one priority. More than one computer investigation has stopped dead in the water when Service agents vanished at the President's need. There's romance in the work of the Service. The intimate access to circles of great power; the esprit-de-corps of a highly trained and disciplined elite; the high responsibility of defending the Chief Executive; the fulfillment of a patriotic duty. And as police work goes, the pay's not bad. But there's squalor in Service work, too. You may get spat upon by protesters howling abuse--and if they get violent, if they get too close, sometimes you have to knock one of them down-- discreetly. The real squalor in Service work is drudgery such as "the quarterlies," traipsing out four times a year, year in, year out, to interview the various pathetic wretches, many of them in prisons and asylums, who have seen fit to threaten the President's life. And then there's the grinding stress of searching all those faces in the endless bustling crowds, looking for hatred, looking for psychosis, looking for the tight, nervous face of an Arthur Bremer, a Squeaky Fromme, a Lee Harvey Oswald. It's watching all those grasping, waving hands for sudden movements, while your ears strain at your radio headphone for the long-rehearsed cry of "Gun!" It's poring, in grinding detail, over the biographies of every rotten loser who ever shot at a President. It's the unsung work of the Protective Research Section, who study scrawled, anonymous death threats with all the meticulous tools of anti-forgery techniques. And it's maintaining the hefty computerized files on anyone who ever threatened the President's life. Civil libertarians have become increasingly concerned at the Government's use of computer files to track American citizens--but the Secret Service file of potential Presidential assassins, which has upward of twenty thousand names, rarely causes a peep of protest. If you EVER state that you intend to kill the President, the Secret Service will want to know and record who you are, where you are, what you are, and what you're up to. If you're a serious threat-- if you're officially considered "of protective interest"-- then the Secret Service may well keep tabs on you for the rest of your natural life. Protecting the President has first call on all the Service's resources. But there's a lot more to the Service's traditions and history than standing guard outside the Oval Office. The Secret Service is the nation's oldest general federal law-enforcement agency. Compared to the Secret Service, the FBI are new-hires and the CIA are temps. The Secret Service was founded 'way back in 1865, at the suggestion of Hugh McCulloch, Abraham Lincoln's Secretary of the Treasury. McCulloch wanted a specialized Treasury police to combat counterfeiting. Abraham Lincoln agreed that this seemed a good idea, and, with a terrible irony, Abraham Lincoln was shot that very night by John Wilkes Booth. The Secret Service originally had nothing to do with protecting Presidents. They didn't take this on as a regular assignment until after the Garfield assassination in 1881. And they didn't get any Congressional money for it until President McKinley was shot in 1901. The Service was originally designed for one purpose: destroying counterfeiters. # There are interesting parallels between the Service's nineteenth-century entry into counterfeiting, and America's twentieth-century entry into computer-crime. In 1865, America's paper currency was a terrible muddle. Security was drastically bad. Currency was printed on the spot by local banks in literally hundreds of different designs. No one really knew what the heck a dollar bill was supposed to look like. Bogus bills passed easily. If some joker told you that a one-dollar bill from the Railroad Bank of Lowell, Massachusetts had a woman leaning on a shield, with a locomotive, a cornucopia, a compass, various agricultural implements, a railroad bridge, and some factories, then you pretty much had to take his word for it. (And in fact he was telling the truth!) SIXTEEN HUNDRED local American banks designed and printed their own paper currency, and there were no general standards for security. Like a badly guarded node in a computer network, badly designed bills were easy to fake, and posed a security hazard for the entire monetary system. No one knew the exact extent of the threat to the currency. There were panicked estimates that as much as a third of the entire national currency was faked. Counterfeiters-- known as "boodlers" in the underground slang of the time-- were mostly technically skilled printers who had gone to the bad. Many had once worked printing legitimate currency. Boodlers operated in rings and gangs. Technical experts engraved the bogus plates--commonly in basements in New York City. Smooth confidence men passed large wads of high-quality, high-denomination fakes, including the really sophisticated stuff-- government bonds, stock certificates, and railway shares. Cheaper, botched fakes were sold or sharewared to low-level gangs of boodler wannabes. (The really cheesy lowlife boodlers merely upgraded real bills by altering face values, changing ones to fives, tens to hundreds, and so on.) The techniques of boodling were little-known and regarded with a certain awe by the mid- nineteenth-century public. The ability to manipulate the system for rip-off seemed diabolically clever. As the skill and daring of the boodlers increased, the situation became intolerable. The federal government stepped in, and began offering its own federal currency, which was printed in fancy green ink, but only on the back--the original "greenbacks." And at first, the improved security of the well-designed, well-printed federal greenbacks seemed to solve the problem; but then the counterfeiters caught on. Within a few years things were worse than ever: a CENTRALIZED system where ALL security was bad! The local police were helpless. The Government tried offering blood money to potential informants, but this met with little success. Banks, plagued by boodling, gave up hope of police help and hired private security men instead. Merchants and bankers queued up by the thousands to buy privately-printed manuals on currency security, slim little books like Laban Heath's INFALLIBLE GOVERNMENT COUNTERFEIT DETECTOR. The back of the book offered Laban Heath's patent microscope for five bucks. Then the Secret Service entered the picture. The first agents were a rough and ready crew. Their chief was one William P. Wood, a former guerilla in the Mexican War who'd won a reputation busting contractor fraudsters for the War Department during the Civil War. Wood, who was also Keeper of the Capital Prison, had a sideline as a counterfeiting expert, bagging boodlers for the federal bounty money. Wood was named Chief of the new Secret Service in July 1865. There were only ten Secret Service agents in all: Wood himself, a handful who'd worked for him in the War Department, and a few former private investigators--counterfeiting experts--whom Wood had won over to public service. (The Secret Service of 1865 was much the size of the Chicago Computer Fraud Task Force or the Arizona Racketeering Unit of 1990.) These ten "Operatives" had an additional twenty or so "Assistant Operatives" and "Informants." Besides salary and per diem, each Secret Service employee received a whopping twenty-five dollars for each boodler he captured. Wood himself publicly estimated that at least HALF of America's currency was counterfeit, a perhaps pardonable perception. Within a year the Secret Service had arrested over 200 counterfeiters. They busted about two hundred boodlers a year for four years straight. Wood attributed his success to travelling fast and light, hitting the bad-guys hard, and avoiding bureaucratic baggage. "Because my raids were made without military escort and I did not ask the assistance of state officers, I surprised the professional counterfeiter." Wood's social message to the once-impudent boodlers bore an eerie ring of Sundevil: "It was also my purpose to convince such characters that it would no longer be healthy for them to ply their vocation without being handled roughly, a fact they soon discovered." William P. Wood, the Secret Service's guerilla pioneer, did not end well. He succumbed to the lure of aiming for the really big score. The notorious Brockway Gang of New York City, headed by William E. Brockway, the "King of the Counterfeiters," had forged a number of government bonds. They'd passed these brilliant fakes on the prestigious Wall Street investment firm of Jay Cooke and Company. The Cooke firm were frantic and offered a huge reward for the forgers' plates. Laboring diligently, Wood confiscated the plates (though not Mr. Brockway) and claimed the reward. But the Cooke company treacherously reneged. Wood got involved in a down-and-dirty lawsuit with the Cooke capitalists. Wood's boss, Secretary of the Treasury McCulloch, felt that Wood's demands for money and glory were unseemly, and even when the reward money finally came through, McCulloch refused to pay Wood anything. Wood found himself mired in a seemingly endless round of federal suits and Congressional lobbying. Wood never got his money. And he lost his job to boot. He resigned in 1869. Wood's agents suffered, too. On May 12, 1869, the second Chief of the Secret Service took over, and almost immediately fired most of Wood's pioneer Secret Service agents: Operatives, Assistants and Informants alike. The practice of receiving $25 per crook was abolished. And the Secret Service began the long, uncertain process of thorough professionalization. Wood ended badly. He must have felt stabbed in the back. In fact his entire organization was mangled. On the other hand, William P. Wood WAS the first head of the Secret Service. William Wood was the pioneer. People still honor his name. Who remembers the name of the SECOND head of the Secret Service? As for William Brockway (also known as "Colonel Spencer"), he was finally arrested by the Secret Service in 1880. He did five years in prison, got out, and was still boodling at the age of seventy-four. # Anyone with an interest in Operation Sundevil-- or in American computer-crime generally-- could scarcely miss the presence of Gail Thackeray, Assistant Attorney General of the State of Arizona. Computer-crime training manuals often cited Thackeray's group and her work; she was the highest-ranking state official to specialize in computer-related offenses. Her name had been on the Sundevil press release (though modestly ranked well after the local federal prosecuting attorney and the head of the Phoenix Secret Service office). As public commentary, and controversy, began to mount about the Hacker Crackdown, this Arizonan state official began to take a higher and higher public profile. Though uttering almost nothing specific about the Sundevil operation itself, she coined some of the most striking soundbites of the growing propaganda war: "Agents are operating in good faith, and I don't think you can say that for the hacker community," was one. Another was the memorable "I am not a mad dog prosecutor" (Houston Chronicle, Sept 2, 1990.) In the meantime, the Secret Service maintained its usual extreme discretion; the Chicago Unit, smarting from the backlash of the Steve Jackson scandal, had gone completely to earth. As I collated my growing pile of newspaper clippings, Gail Thackeray ranked as a comparative fount of public knowledge on police operations. I decided that I had to get to know Gail Thackeray. I wrote to her at the Arizona Attorney General's Office. Not only did she kindly reply to me, but, to my astonishment, she knew very well what "cyberpunk" science fiction was. Shortly after this, Gail Thackeray lost her job. And I temporarily misplaced my own career as a science-fiction writer, to become a full-time computer-crime journalist. In early March, 1991, I flew to Phoenix, Arizona, to interview Gail Thackeray for my book on the hacker crackdown. # "Credit cards didn't used to cost anything to get," says Gail Thackeray. "Now they cost forty bucks-- and that's all just to cover the costs from RIP-OFF ARTISTS." Electronic nuisance criminals are parasites. One by one they're not much harm, no big deal. But they never come just one by one. They come in swarms, heaps, legions, sometimes whole subcultures. And they bite. Every time we buy a credit card today, we lose a little financial vitality to a particular species of bloodsucker. What, in her expert opinion, are the worst forms of electronic crime, I ask, consulting my notes. Is it--credit card fraud? Breaking into ATM bank machines? Phone-phreaking? Computer intrusions? Software viruses? Access-code theft? Records tampering? Software piracy? Pornographic bulletin boards? Satellite TV piracy? Theft of cable service? It's a long list. By the time I reach the end of it I feel rather depressed. "Oh no," says Gail Thackeray, leaning forward over the table, her whole body gone stiff with energetic indignation, "the biggest damage is telephone fraud. Fake sweepstakes, fake charities. Boiler-room con operations. You could pay off the national debt with what these guys steal. . . . They target old people, they get hold of credit ratings and demographics, they rip off the old and the weak." The words come tumbling out of her. It's low-tech stuff, your everyday boiler-room fraud. Grifters, conning people out of money over the phone, have been around for decades. This is where the word "phony" came from! It's just that it's so much EASIER now, horribly facilitated by advances in technology and the byzantine structure of the modern phone system. The same professional fraudsters do it over and over, Thackeray tells me, they hide behind dense onion-shells of fake companies. . . fake holding corporations nine or ten layers deep, registered all over the map. They get a phone installed under a false name in an empty safe-house. And then they call-forward everything out of that phone to yet another phone, a phone that may even be in another STATE. And they don't even pay the charges on their phones; after a month or so, they just split; set up somewhere else in another Podunkville with the same seedy crew of veteran phone-crooks. They buy or steal commercial credit card reports, slap them on the PC, have a program pick out people over sixty-five who pay a lot to charities. A whole subculture living off this, merciless folks on the con. "The `light-bulbs for the blind' people," Thackeray muses, with a special loathing. "There's just no end to them." We're sitting in a downtown diner in Phoenix, Arizona. It's a tough town, Phoenix. A state capital seeing some hard times. Even to a Texan like myself, Arizona state politics seem rather baroque. There was, and remains, endless trouble over the Martin Luther King holiday, the sort of stiff-necked, foot-shooting incident for which Arizona politics seem famous. There was Evan Mecham, the eccentric Republican millionaire governor who was impeached, after reducing state government to a ludicrous shambles. Then there was the national Keating scandal, involving Arizona savings and loans, in which both of Arizona's U.S. senators, DeConcini and McCain, played sadly prominent roles. And the very latest is the bizarre AzScam case, in which state legislators were videotaped, eagerly taking cash from an informant of the Phoenix city police department, who was posing as a Vegas mobster. "Oh," says Thackeray cheerfully. "These people are amateurs here, they thought they were finally getting to play with the big boys. They don't have the least idea how to take a bribe! It's not institutional corruption. It's not like back in Philly." Gail Thackeray was a former prosecutor in Philadelphia. Now she's a former assistant attorney general of the State of Arizona. Since moving to Arizona in 1986, she had worked under the aegis of Steve Twist, her boss in the Attorney General's office. Steve Twist wrote Arizona's pioneering computer crime laws and naturally took an interest in seeing them enforced. It was a snug niche, and Thackeray's Organized Crime and Racketeering Unit won a national reputation for ambition and technical knowledgeability. . . . Until the latest election in Arizona. Thackeray's boss ran for the top job, and lost. The victor, the new Attorney General, apparently went to some pains to eliminate the bureaucratic traces of his rival, including his pet group--Thackeray's group. Twelve people got their walking papers. Now Thackeray's painstakingly assembled computer lab sits gathering dust somewhere in the glass-and-concrete Attorney General's HQ on 1275 Washington Street. Her computer-crime books, her painstakingly garnered back issues of phreak and hacker zines, all bought at her own expense--are piled in boxes somewhere. The State of Arizona is simply not particularly interested in electronic racketeering at the moment. At the moment of our interview, Gail Thackeray, officially unemployed, is working out of the county sheriff's office, living on her savings, and prosecuting several cases--working 60-hour weeks, just as always-- for no pay at all. "I'm trying to train people," she mutters. Half her life seems to be spent training people--merely pointing out, to the naive and incredulous (such as myself) that this stuff is ACTUALLY GOING ON OUT THERE. It's a small world, computer crime. A young world. Gail Thackeray, a trim blonde Baby-Boomer who favors Grand Canyon white-water rafting to kill some slow time, is one of the world's most senior, most veteran "hacker-trackers." Her mentor was Donn Parker, the California think-tank theorist who got it all started `way back in the mid-70s, the "grandfather of the field," "the great bald eagle of computer crime." And what she has learned, Gail Thackeray teaches. Endlessly. Tirelessly. To anybody. To Secret Service agents and state police, at the Glynco, Georgia federal training center. To local police, on "roadshows" with her slide projector and notebook. To corporate security personnel. To journalists. To parents. Even CROOKS look to Gail Thackeray for advice. Phone-phreaks call her at the office. They know very well who she is. They pump her for information on what the cops are up to, how much they know. Sometimes whole CROWDS of phone phreaks, hanging out on illegal conference calls, will call Gail Thackeray up. They taunt her. And, as always, they boast. Phone-phreaks, real stone phone-phreaks, simply CANNOT SHUT UP. They natter on for hours. Left to themselves, they mostly talk about the intricacies of ripping-off phones; it's about as interesting as listening to hot-rodders talk about suspension and distributor-caps. They also gossip cruelly about each other. And when talking to Gail Thackeray, they incriminate themselves. "I have tapes," Thackeray says coolly. Phone phreaks just talk like crazy. "Dial-Tone" out in Alabama has been known to spend half-an-hour simply reading stolen phone-codes aloud into voice-mail answering machines. Hundreds, thousands of numbers, recited in a monotone, without a break--an eerie phenomenon. When arrested, it's a rare phone phreak who doesn't inform at endless length on everybody he knows. Hackers are no better. What other group of criminals, she asks rhetorically, publishes newsletters and holds conventions? She seems deeply nettled by the sheer brazenness of this behavior, though to an outsider, this activity might make one wonder whether hackers should be considered "criminals" at all. Skateboarders have magazines, and they trespass a lot. Hot rod people have magazines and they break speed limits and sometimes kill people. . . . I ask her whether it would be any loss to society if phone phreaking and computer hacking, as hobbies, simply dried up and blew away, so that nobody ever did it again. She seems surprised. "No," she says swiftly. "Maybe a little. . . in the old days. . .the MIT stuff. . . . But there's a lot of wonderful, legal stuff you can do with computers now, you don't have to break into somebody else's just to learn. You don't have that excuse. You can learn all you like." Did you ever hack into a system? I ask. The trainees do it at Glynco. Just to demonstrate system vulnerabilities. She's cool to the notion. Genuinely indifferent. "What kind of computer do you have?" "A Compaq 286LE," she mutters. "What kind do you WISH you had?" At this question, the unmistakable light of true hackerdom flares in Gail Thackeray's eyes. She becomes tense, animated, the words pour out: "An Amiga 2000 with an IBM card and Mac emulation! The most common hacker machines are Amigas and Commodores. And Apples." If she had the Amiga, she enthuses, she could run a whole galaxy of seized computer-evidence disks on one convenient multifunctional machine. A cheap one, too. Not like the old Attorney General lab, where they had an ancient CP/M machine, assorted Amiga flavors and Apple flavors, a couple IBMS, all the utility software. . .but no Commodores. The workstations down at the Attorney General's are Wang dedicated word-processors. Lame machines tied in to an office net--though at least they get on- line to the Lexis and Westlaw legal data services. I don't say anything. I recognize the syndrome, though. This computer-fever has been running through segments of our society for years now. It's a strange kind of lust: K-hunger, Meg-hunger; but it's a shared disease; it can kill parties dead, as conversation spirals into the deepest and most deviant recesses of software releases and expensive peripherals. . . . The mark of the hacker beast. I have it too. The whole "electronic community," whatever the hell that is, has it. Gail Thackeray has it. Gail Thackeray is a hacker cop. My immediate reaction is a strong rush of indignant pity: WHY DOESN'T SOMEBODY BUY THIS WOMAN HER AMIGA?! It's not like she's asking for a Cray X-MP supercomputer mainframe; an Amiga's a sweet little cookie-box thing. We're losing zillions in organized fraud; prosecuting and defending a single hacker case in court can cost a hundred grand easy. How come nobody can come up with four lousy grand so this woman can do her job? For a hundred grand we could buy every computer cop in America an Amiga. There aren't that many of 'em. Computers. The lust, the hunger, for computers. The loyalty they inspire, the intense sense of possessiveness. The culture they have bred. I myself am sitting in downtown Phoenix, Arizona because it suddenly occurred to me that the police might-- just MIGHT--come and take away my computer. The prospect of this, the mere IMPLIED THREAT, was unbearable. It literally changed my life. It was changing the lives of many others. Eventually it would change everybody's life. Gail Thackeray was one of the top computer-crime people in America. And I was just some novelist, and yet I had a better computer than hers. PRACTICALLY EVERYBODY I KNEW had a better computer than Gail Thackeray and her feeble laptop 286. It was like sending the sheriff in to clean up Dodge City and arming her with a slingshot cut from an old rubber tire. But then again, you don't need a howitzer to enforce the law. You can do a lot just with a badge. With a badge alone, you can basically wreak havoc, take a terrible vengeance on wrongdoers. Ninety percent of "computer crime investigation" is just "crime investigation:" names, places, dossiers, modus operandi, search warrants, victims, complainants, informants. . . . What will computer crime look like in ten years? Will it get better? Did "Sundevil" send 'em reeling back in confusion? It'll be like it is now, only worse, she tells me with perfect conviction. Still there in the background, ticking along, changing with the times: the criminal underworld. It'll be like drugs are. Like our problems with alcohol. All the cops and laws in the world never solved our problems with alcohol. If there's something people want, a certain percentage of them are just going to take it. Fifteen percent of the populace will never steal. Fifteen percent will steal most anything not nailed down. The battle is for the hearts and minds of the remaining seventy percent. And criminals catch on fast. If there's not "too steep a learning curve"-- if it doesn't require a baffling amount of expertise and practice-- then criminals are often some of the first through the gate of a new technology. Especially if it helps them to hide. They have tons of cash, criminals. The new communications tech-- like pagers, cellular phones, faxes, Federal Express--were pioneered by rich corporate people, and by criminals. In the early years of pagers and beepers, dope dealers were so enthralled this technology that owing a beeper was practically prima facie evidence of cocaine dealing. CB radio exploded when the speed limit hit 55 and breaking the highway law became a national pastime. Dope dealers send cash by Federal Express, despite, or perhaps BECAUSE OF, the warnings in FedEx offices that tell you never to try this. Fed Ex uses X-rays and dogs on their mail, to stop drug shipments. That doesn't work very well. Drug dealers went wild over cellular phones. There are simple methods of faking ID on cellular phones, making the location of the call mobile, free of charge, and effectively untraceable. Now victimized cellular companies routinely bring in vast toll-lists of calls to Colombia and Pakistan. Judge Greene's fragmentation of the phone company is driving law enforcement nuts. Four thousand telecommunications companies. Fraud skyrocketing. Every temptation in the world available with a phone and a credit card number. Criminals untraceable. A galaxy of "new neat rotten things to do." If there were one thing Thackeray would like to have, it would be an effective legal end-run through this new fragmentation minefield. It would be a new form of electronic search warrant, an "electronic letter of marque" to be issued by a judge. It would create a new category of "electronic emergency." Like a wiretap, its use would be rare, but it would cut across state lines and force swift cooperation from all concerned. Cellular, phone, laser, computer network, PBXes, AT&T, Baby Bells, long-distance entrepreneurs, packet radio. Some document, some mighty court-order, that could slice through four thousand separate forms of corporate red-tape, and get her at once to the source of calls, the source of email threats and viruses, the sources of bomb threats, kidnapping threats. "From now on," she says, "the Lindbergh baby will always die." Something that would make the Net sit still, if only for a moment. Something that would get her up to speed. Seven league boots. That's what she really needs. "Those guys move in nanoseconds and I'm on the Pony Express." And then, too, there's the coming international angle. Electronic crime has never been easy to localize, to tie to a physical jurisdiction. And phone-phreaks and hackers loathe boundaries, they jump them whenever they can. The English. The Dutch. And the Germans, especially the ubiquitous Chaos Computer Club. The Australians. They've all learned phone-phreaking from America. It's a growth mischief industry. The multinational networks are global, but governments and the police simply aren't. Neither are the laws. Or the legal frameworks for citizen protection. One language is global, though--English. Phone phreaks speak English; it's their native tongue even if they're Germans. English may have started in England but now it's the Net language; it might as well be called "CNNese." Asians just aren't much into phone phreaking. They're the world masters at organized software piracy. The French aren't into phone-phreaking either. The French are into computerized industrial espionage. In the old days of the MIT righteous hackerdom, crashing systems didn't hurt anybody. Not all that much, anyway. Not permanently. Now the players are more venal. Now the consequences are worse. Hacking will begin killing people soon. Already there are methods of stacking calls onto 911 systems, annoying the police, and possibly causing the death of some poor soul calling in with a genuine emergency. Hackers in Amtrak computers, or air-traffic control computers, will kill somebody someday. Maybe a lot of people. Gail Thackeray expects it. And the viruses are getting nastier. The "Scud" virus is the latest one out. It wipes hard-disks. According to Thackeray, the idea that phone-phreaks are Robin Hoods is a fraud. They don't deserve this repute. Basically, they pick on the weak. AT&T now protects itself with the fearsome ANI (Automatic Number Identification) trace capability. When AT&T wised up and tightened security generally, the phreaks drifted into the Baby Bells. The Baby Bells lashed out in 1989 and 1990, so the phreaks switched to smaller long-distance entrepreneurs. Today, they are moving into locally owned PBXes and voice-mail systems, which are full of security holes, dreadfully easy to hack. These victims aren't the moneybags Sheriff of Nottingham or Bad King John, but small groups of innocent people who find it hard to protect themselves, and who really suffer from these depredations. Phone phreaks pick on the weak. They do it for power. If it were legal, they wouldn't do it. They don't want service, or knowledge, they want the thrill of power-tripping. There's plenty of knowledge or service around if you're willing to pay. Phone phreaks don't pay, they steal. It's because it is illegal that it feels like power, that it gratifies their vanity. I leave Gail Thackeray with a handshake at the door of her office building-- a vast International-Style office building downtown. The Sheriff's office is renting part of it. I get the vague impression that quite a lot of the building is empty--real estate crash. In a Phoenix sports apparel store, in a downtown mall, I meet the "Sun Devil" himself. He is the cartoon mascot of Arizona State University, whose football stadium, "Sundevil," is near the local Secret Service HQ--hence the name Operation Sundevil. The Sun Devil himself is named "Sparky." Sparky the Sun Devil is maroon and bright yellow, the school colors. Sparky brandishes a three-tined yellow pitchfork. He has a small mustache, pointed ears, a barbed tail, and is dashing forward jabbing the air with the pitchfork, with an expression of devilish glee. Phoenix was the home of Operation Sundevil. The Legion of Doom ran a hacker bulletin board called "The Phoenix Project." An Australian hacker named "Phoenix" once burrowed through the Internet to attack Cliff Stoll, then bragged and boasted about it to The New York Times. This net of coincidence is both odd and meaningless. The headquarters of the Arizona Attorney General, Gail Thackeray's former workplace, is on 1275 Washington Avenue. Many of the downtown streets in Phoenix are named after prominent American presidents: Washington, Jefferson, Madison. . . . After dark, all the employees go home to their suburbs. Washington, Jefferson and Madison--what would be the Phoenix inner city, if there were an inner city in this sprawling automobile-bred town--become the haunts of transients and derelicts. The homeless. The sidewalks along Washington are lined with orange trees. Ripe fallen fruit lies scattered like croquet balls on the sidewalks and gutters. No one seems to be eating them. I try a fresh one. It tastes unbearably bitter. The Attorney General's office, built in 1981 during the Babbitt administration, is a long low two-story building of white cement and wall-sized sheets of curtain-glass. Behind each glass wall is a lawyer's office, quite open and visible to anyone strolling by. Across the street is a dour government building labelled simply ECONOMIC SECURITY, something that has not been in great supply in the American Southwest lately. The offices are about twelve feet square. They feature tall wooden cases full of red-spined lawbooks; Wang computer monitors; telephones; Post-it notes galore. Also framed law diplomas and a general excess of bad Western landscape art. Ansel Adams photos are a big favorite, perhaps to compensate for the dismal specter of the parking lot, two acres of striped black asphalt, which features gravel landscaping and some sickly-looking barrel cacti. It has grown dark. Gail Thackeray has told me that the people who work late here, are afraid of muggings in the parking lot. It seems cruelly ironic that a woman tracing electronic racketeers across the interstate labyrinth of Cyberspace should fear an assault by a homeless derelict in the parking lot of her own workplace. Perhaps this is less than coincidence. Perhaps these two seemingly disparate worlds are somehow generating one another. The poor and disenfranchised take to the streets, while the rich and computer-equipped, safe in their bedrooms, chatter over their modems. Quite often the derelicts kick the glass out and break in to the lawyers' offices, if they see something they need or want badly enough. I cross the parking lot to the street behind the Attorney General's office. A pair of young tramps are bedding down on flattened sheets of cardboard, under an alcove stretching over the sidewalk. One tramp wears a glitter-covered T-shirt reading "CALIFORNIA" in Coca-Cola cursive. His nose and cheeks look chafed and swollen; they glisten with what seems to be Vaseline. The other tramp has a ragged long-sleeved shirt and lank brown hair parted in the middle. They both wear blue jeans coated in grime. They are both drunk. "You guys crash here a lot?" I ask them. They look at me warily. I am wearing black jeans, a black pinstriped suit jacket and a black silk tie. I have odd shoes and a funny haircut. "It's our first time here," says the red-nosed tramp unconvincingly. There is a lot of cardboard stacked here. More than any two people could use. "We usually stay at the Vinnie's down the street," says the brown-haired tramp, puffing a Marlboro with a meditative air, as he sprawls with his head on a blue nylon backpack. "The Saint Vincent's." "You know who works in that building over there?" I ask, pointing. The brown-haired tramp shrugs. "Some kind of attorneys, it says." We urge one another to take it easy. I give them five bucks. A block down the street I meet a vigorous workman who is wheeling along some kind of industrial trolley; it has what appears to be a tank of propane on it. We make eye contact. We nod politely. I walk past him. "Hey! Excuse me sir!" he says. "Yes?" I say, stopping and turning. "Have you seen," the guy says rapidly, "a black guy, about 6'7", scars on both his cheeks like this--" he gestures-- "wears a black baseball cap on backwards, wandering around here anyplace?" "Sounds like I don't much WANT to meet him," I say. "He took my wallet," says my new acquaintance. "Took it this morning. Y'know, some people would be SCARED of a guy like that. But I'm not scared. I'm from Chicago. I'm gonna hunt him down. We do things like that in Chicago." "Yeah?" "I went to the cops and now he's got an APB out on his ass," he says with satisfaction. "You run into him, you let me know." "Okay," I say. "What is your name, sir?" "Stanley. . . ." "And how can I reach you?" "Oh," Stanley says, in the same rapid voice, "you don't have to reach, uh, me. You can just call the cops. Go straight to the cops." He reaches into a pocket and pulls out a greasy piece of pasteboard. "See, here's my report on him." I look. The "report," the size of an index card, is labelled PRO-ACT: Phoenix Residents Opposing Active Crime Threat. . . . or is it Organized Against Crime Threat? In the darkening street it's hard to read. Some kind of vigilante group? Neighborhood watch? I feel very puzzled. "Are you a police officer, sir?" He smiles, seems very pleased by the question. "No," he says. "But you are a `Phoenix Resident?'" "Would you believe a homeless person," Stanley says. "Really? But what's with the. . . ." For the first time I take a close look at Stanley's trolley. It's a rubber-wheeled thing of industrial metal, but the device I had mistaken for a tank of propane is in fact a water-cooler. Stanley also has an Army duffel-bag, stuffed tight as a sausage with clothing or perhaps a tent, and, at the base of his trolley, a cardboard box and a battered leather briefcase. "I see," I say, quite at a loss. For the first time I notice that Stanley has a wallet. He has not lost his wallet at all. It is in his back pocket and chained to his belt. It's not a new wallet. It seems to have seen a lot of wear. "Well, you know how it is, brother," says Stanley. Now that I know that he is homeless--A POSSIBLE THREAT--my entire perception of him has changed in an instant. His speech, which once seemed just bright and enthusiastic, now seems to have a dangerous tang of mania. "I have to do this!" he assures me. "Track this guy down. . . . It's a thing I do. . . you know. . .to keep myself together!" He smiles, nods, lifts his trolley by its decaying rubber handgrips. "Gotta work together, y'know," Stanley booms, his face alight with cheerfulness, "the police can't do everything!" The gentlemen I met in my stroll in downtown Phoenix are the only computer illiterates in this book. To regard them as irrelevant, however, would be a grave mistake. As computerization spreads across society, the populace at large is subjected to wave after wave of future shock. But, as a necessary converse, the "computer community" itself is subjected to wave after wave of incoming computer illiterates. How will those currently enjoying America's digital bounty regard, and treat, all this teeming refuse yearning to breathe free? Will the electronic frontier be another Land of Opportunity-- or an armed and monitored enclave, where the disenfranchised snuggle on their cardboard at the locked doors of our houses of justice? Some people just don't get along with computers. They can't read. They can't type. They just don't have it in their heads to master arcane instructions in wirebound manuals. Somewhere, the process of computerization of the populace will reach a limit. Some people-- quite decent people maybe, who might have thrived in any other situation-- will be left irretrievably outside the bounds. What's to be done with these people, in the bright new shiny electroworld? How will they be regarded, by the mouse-whizzing masters of cyberspace? With contempt? Indifference? Fear? In retrospect, it astonishes me to realize how quickly poor Stanley became a perceived threat. Surprise and fear are closely allied feelings. And the world of computing is full of surprises. I met one character in the streets of Phoenix whose role in this book is supremely and directly relevant. That personage was Stanley's giant thieving scarred phantom. This phantasm is everywhere in this book. He is the specter haunting cyberspace. Sometimes he's a maniac vandal ready to smash the phone system for no sane reason at all. Sometimes he's a fascist fed, coldly programming his mighty mainframes to destroy our Bill of Rights. Sometimes he's a telco bureaucrat, covertly conspiring to register all modems in the service of an Orwellian surveillance regime. Mostly, though, this fearsome phantom is a "hacker." He's strange, he doesn't belong, he's not authorized, he doesn't smell right, he's not keeping his proper place, he's not one of us. The focus of fear is the hacker, for much the same reasons that Stanley's fancied assailant is black. Stanley's demon can't go away, because he doesn't exist. Despite singleminded and tremendous effort, he can't be arrested, sued, jailed, or fired. The only constructive way to do ANYTHING about him is to learn more about Stanley himself. This learning process may be repellent, it may be ugly, it may involve grave elements of paranoiac confusion, but it's necessary. Knowing Stanley requires something more than class-crossing condescension. It requires more than steely legal objectivity. It requires human compassion and sympathy. To know Stanley is to know his demon. If you know the other guy's demon, then maybe you'll come to know some of your own. You'll be able to separate reality from illusion. And then you won't do your cause, and yourself, more harm than good. Like poor damned Stanley from Chicago did. # The Federal Computer Investigations Committee (FCIC) is the most important and influential organization in the realm of American computer-crime. Since the police of other countries have largely taken their computer-crime cues from American methods, the FCIC might well be called the most important computer crime group in the world. It is also, by federal standards, an organization of great unorthodoxy. State and local investigators mix with federal agents. Lawyers, financial auditors and computer-security programmers trade notes with street cops. Industry vendors and telco security people show up to explain their gadgetry and plead for protection and justice. Private investigators, think-tank experts and industry pundits throw in their two cents' worth. The FCIC is the antithesis of a formal bureaucracy. Members of the FCIC are obscurely proud of this fact; they recognize their group as aberrant, but are entirely convinced that this, for them, outright WEIRD behavior is nevertheless ABSOLUTELY NECESSARY to get their jobs done. FCIC regulars --from the Secret Service, the FBI, the IRS, the Department of Labor, the offices of federal attorneys, state police, the Air Force, from military intelligence-- often attend meetings, held hither and thither across the country, at their own expense. The FCIC doesn't get grants. It doesn't charge membership fees. It doesn't have a boss. It has no headquarters-- just a mail drop in Washington DC, at the Fraud Division of the Secret Service. It doesn't have a budget. It doesn't have schedules. It meets three times a year--sort of. Sometimes it issues publications, but the FCIC has no regular publisher, no treasurer, not even a secretary. There are no minutes of FCIC meetings. Non-federal people are considered "non-voting members," but there's not much in the way of elections. There are no badges, lapel pins or certificates of membership. Everyone is on a first-name basis. There are about forty of them. Nobody knows how many, exactly. People come, people go-- sometimes people "go" formally but still hang around anyway. Nobody has ever exactly figured out what "membership" of this "Committee" actually entails. Strange as this may seem to some, to anyone familiar with the social world of computing, the "organization" of the FCIC is very recognizable. For years now, economists and management theorists have speculated that the tidal wave of the information revolution would destroy rigid, pyramidal bureaucracies, where everything is top-down and centrally controlled. Highly trained "employees" would take on much greater autonomy, being self-starting, and self-motivating, moving from place to place, task to task, with great speed and fluidity. "Ad-hocracy" would rule, with groups of people spontaneously knitting together across organizational lines, tackling the problem at hand, applying intense computer-aided expertise to it, and then vanishing whence they came. This is more or less what has actually happened in the world of federal computer investigation. With the conspicuous exception of the phone companies, which are after all over a hundred years old, practically EVERY organization that plays any important role in this book functions just like the FCIC. The Chicago Task Force, the Arizona Racketeering Unit, the Legion of Doom, the Phrack crowd, the Electronic Frontier Foundation--they ALL look and act like "tiger teams" or "user's groups." They are all electronic ad-hocracies leaping up spontaneously to attempt to meet a need. Some are police. Some are, by strict definition, criminals. Some are political interest-groups. But every single group has that same quality of apparent spontaneity--"Hey, gang! My uncle's got a barn--let's put on a show!" Every one of these groups is embarrassed by this "amateurism," and, for the sake of their public image in a world of non-computer people, they all attempt to look as stern and formal and impressive as possible. These electronic frontier-dwellers resemble groups of nineteenth-century pioneers hankering after the respectability of statehood. There are however, two crucial differences in the historical experience of these "pioneers" of the nineteeth and twenty-first centuries. First, powerful information technology DOES play into the hands of small, fluid, loosely organized groups. There have always been "pioneers," "hobbyists," "amateurs," "dilettantes," "volunteers," "movements," "users' groups" and "blue-ribbon panels of experts" around. But a group of this kind--when technically equipped to ship huge amounts of specialized information, at lightning speed, to its members, to government, and to the press--is simply a different kind of animal. It's like the difference between an eel and an electric eel. The second crucial change is that American society is currently in a state approaching permanent technological revolution. In the world of computers particularly, it is practically impossible to EVER stop being a "pioneer," unless you either drop dead or deliberately jump off the bus. The scene has never slowed down enough to become well-institutionalized. And after twenty, thirty, forty years the "computer revolution" continues to spread, to permeate new corners of society. Anything that really works is already obsolete. If you spend your entire working life as a "pioneer," the word "pioneer" begins to lose its meaning. Your way of life looks less and less like an introduction to something else" more stable and organized, and more and more like JUST THE WAY THINGS ARE. A "permanent revolution" is really a contradiction in terms. If "turmoil" lasts long enough, it simply becomes A NEW KIND OF SOCIETY--still the same game of history, but new players, new rules. Apply this to the world of late twentieth-century law enforcement, and the implications are novel and puzzling indeed. Any bureaucratic rulebook you write about computer-crime will be flawed when you write it, and almost an antique by the time it sees print. The fluidity and fast reactions of the FCIC give them a great advantage in this regard, which explains their success. Even with the best will in the world (which it does not, in fact, possess) it is impossible for an organization the size of the U.S. Federal Bureau of Investigation to get up to speed on the theory and practice of computer crime. If they tried to train all their agents to do this, it would be SUICIDAL, as they would NEVER BE ABLE TO DO ANYTHING ELSE. The FBI does try to train its agents in the basics of electronic crime, at their base in Quantico, Virginia. And the Secret Service, along with many other law enforcement groups, runs quite successful and well-attended training courses on wire fraud, business crime, and computer intrusion at the Federal Law Enforcement Training Center (FLETC, pronounced "fletsy") in Glynco, Georgia. But the best efforts of these bureaucracies does not remove the absolute need for a "cutting-edge mess" like the FCIC. For you see--the members of FCIC ARE the trainers of the rest of law enforcement. Practically and literally speaking, they are the Glynco computer-crime faculty by another name. If the FCIC went over a cliff on a bus, the U.S. law enforcement community would be rendered deaf dumb and blind in the world of computer crime, and would swiftly feel a desperate need to reinvent them. And this is no time to go starting from scratch. On June 11, 1991, I once again arrived in Phoenix, Arizona, for the latest meeting of the Federal Computer Investigations Committee. This was more or less the twentieth meeting of this stellar group. The count was uncertain, since nobody could figure out whether to include the meetings of "the Colluquy," which is what the FCIC was called in the mid-1980s before it had even managed to obtain the dignity of its own acronym. Since my last visit to Arizona, in May, the local AzScam bribery scandal had resolved itself in a general muddle of humiliation. The Phoenix chief of police, whose agents had videotaped nine state legislators up to no good, had resigned his office in a tussle with the Phoenix city council over the propriety of his undercover operations. The Phoenix Chief could now join Gail Thackeray and eleven of her closest associates in the shared experience of politically motivated unemployment. As of June, resignations were still continuing at the Arizona Attorney General's office, which could be interpreted as either a New Broom Sweeping Clean or a Night of the Long Knives Part II, depending on your point of view. The meeting of FCIC was held at the Scottsdale Hilton Resort. Scottsdale is a wealthy suburb of Phoenix, known as "Scottsdull" to scoffing local trendies, but well-equipped with posh shopping-malls and manicured lawns, while conspicuously undersupplied with homeless derelicts. The Scottsdale Hilton Resort was a sprawling hotel in postmodern crypto-Southwestern style. It featured a "mission bell tower" plated in turquoise tile and vaguely resembling a Saudi minaret. Inside it was all barbarically striped Santa Fe Style decor. There was a health spa downstairs and a large oddly-shaped pool in the patio. A poolside umbrella-stand offered Ben and Jerry's politically correct Peace Pops. I registered as a member of FCIC, attaining a handy discount rate, then went in search of the Feds. Sure enough, at the back of the hotel grounds came the unmistakable sound of Gail Thackeray holding forth. Since I had also attended the Computers Freedom and Privacy conference (about which more later), this was the second time I had seen Thackeray in a group of her law enforcement colleagues. Once again I was struck by how simply pleased they seemed to see her. It was natural that she'd get SOME attention, as Gail was one of two women in a group of some thirty men; but there was a lot more to it than that. Gail Thackeray personifies the social glue of the FCIC. They could give a damn about her losing her job with the Attorney General. They were sorry about it, of course, but hell, they'd all lost jobs. If they were the kind of guys who liked steady boring jobs, they would never have gotten into computer work in the first place. I wandered into her circle and was immediately introduced to five strangers. The conditions of my visit at FCIC were reviewed. I would not quote anyone directly. I would not tie opinions expressed to the agencies of the attendees. I would not (a purely hypothetical example) report the conversation of a guy from the Secret Service talking quite civilly to a guy from the FBI, as these two agencies NEVER talk to each other, and the IRS (also present, also hypothetical) NEVER TALKS TO ANYBODY. Worse yet, I was forbidden to attend the first conference. And I didn't. I have no idea what the FCIC was up to behind closed doors that afternoon. I rather suspect that they were engaging in a frank and thorough confession of their errors, goof-ups and blunders, as this has been a feature of every FCIC meeting since their legendary Memphis beer-bust of 1986. Perhaps the single greatest attraction of FCIC is that it is a place where you can go, let your hair down, and completely level with people who actually comprehend what you are talking about. Not only do they understand you, but they REALLY PAY ATTENTION, they are GRATEFUL FOR YOUR INSIGHTS, and they FORGIVE YOU, which in nine cases out of ten is something even your boss can't do, because as soon as you start talking "ROM," "BBS," or "T-1 trunk," his eyes glaze over. I had nothing much to do that afternoon. The FCIC were beavering away in their conference room. Doors were firmly closed, windows too dark to peer through. I wondered what a real hacker, a computer intruder, would do at a meeting like this. The answer came at once. He would "trash" the place. Not reduce the place to trash in some orgy of vandalism; that's not the use of the term in the hacker milieu. No, he would quietly EMPTY THE TRASH BASKETS and silently raid any valuable data indiscreetly thrown away. Journalists have been known to do this. (Journalists hunting information have been known to do almost every single unethical thing that hackers have ever done. They also throw in a few awful techniques all their own.) The legality of `trashing' is somewhat dubious but it is not in fact flagrantly illegal. It was, however, absurd to contemplate trashing the FCIC. These people knew all about trashing. I wouldn't last fifteen seconds. The idea sounded interesting, though. I'd been hearing a lot about the practice lately. On the spur of the moment, I decided I would try trashing the office ACROSS THE HALL from the FCIC, an area which had nothing to do with the investigators. The office was tiny; six chairs, a table. . . . Nevertheless, it was open, so I dug around in its plastic trash can. To my utter astonishment, I came up with the torn scraps of a SPRINT long-distance phone bill. More digging produced a bank statement and the scraps of a hand-written letter, along with gum, cigarette ashes, candy wrappers and a day-old-issue of USA TODAY. The trash went back in its receptacle while the scraps of data went into my travel bag. I detoured through the hotel souvenir shop for some Scotch tape and went up to my room. Coincidence or not, it was quite true. Some poor soul had, in fact, thrown a SPRINT bill into the hotel's trash. Date May 1991, total amount due: $252.36. Not a business phone, either, but a residential bill, in the name of someone called Evelyn (not her real name). Evelyn's records showed a ## PAST DUE BILL ##! Here was her nine-digit account ID. Here was a stern computer-printed warning: "TREAT YOUR FONCARD AS YOU WOULD ANY CREDIT CARD. TO SECURE AGAINST FRAUD, NEVER GIVE YOUR FONCARD NUMBER OVER THE PHONE UNLESS YOU INITIATED THE CALL. IF YOU RECEIVE SUSPICIOUS CALLS PLEASE NOTIFY CUSTOMER SERVICE IMMEDIATELY!" I examined my watch. Still plenty of time left for the FCIC to carry on. I sorted out the scraps of Evelyn's SPRINT bill and re-assembled them with fresh Scotch tape. Here was her ten-digit FONCARD number. Didn't seem to have the ID number necessary to cause real fraud trouble. I did, however, have Evelyn's home phone number. And the phone numbers for a whole crowd of Evelyn's long-distance friends and acquaintances. In San Diego, Folsom, Redondo, Las Vegas, La Jolla, Topeka, and Northampton Massachusetts. Even somebody in Australia! I examined other documents. Here was a bank statement. It was Evelyn's IRA account down at a bank in San Mateo California (total balance $1877.20). Here was a charge-card bill for $382.64. She was paying it off bit by bit. Driven by motives that were completely unethical and prurient, I now examined the handwritten notes. They had been torn fairly thoroughly, so much so that it took me almost an entire five minutes to reassemble them. They were drafts of a love letter. They had been written on the lined stationery of Evelyn's employer, a biomedical company. Probably written at work when she should have been doing something else. "Dear Bob," (not his real name) "I guess in everyone's life there comes a time when hard decisions have to be made, and this is a difficult one for me--very upsetting. Since you haven't called me, and I don't understand why, I can only surmise it's because you don't want to. I thought I would have heard from you Friday. I did have a few unusual problems with my phone and possibly you tried, I hope so. "Robert, you asked me to `let go'. . . ." The first note ended. UNUSUAL PROBLEMS WITH HER PHONE? I looked swiftly at the next note. "Bob, not hearing from you for the whole weekend has left me very perplexed. . . ." Next draft. "Dear Bob, there is so much I don't understand right now, and I wish I did. I wish I could talk to you, but for some unknown reason you have elected not to call--this is so difficult for me to understand. . . ." She tried again. "Bob, Since I have always held you in such high esteem, I had every hope that we could remain good friends, but now one essential ingredient is missing-- respect. Your ability to discard people when their purpose is served is appalling to me. The kindest thing you could do for me now is to leave me alone. You are no longer welcome in my heart or home. . . ." Try again. "Bob, I wrote a very factual note to you to say how much respect I had lost for you, by the way you treat people, me in particular, so uncaring and cold. The kindest thing you can do for me is to leave me alone entirely, as you are no longer welcome in my heart or home. I would appreciate it if you could retire your debt to me as soon as possible--I wish no link to you in any way. Sincerely, Evelyn." Good heavens, I thought, the bastard actually owes her money! I turned to the next page. "Bob: very simple. GOODBYE! No more mind games--no more fascination-- no more coldness--no more respect for you! It's over--Finis. Evie" There were two versions of the final brushoff letter, but they read about the same. Maybe she hadn't sent it. The final item in my illicit and shameful booty was an envelope addressed to "Bob" at his home address, but it had no stamp on it and it hadn't been mailed. Maybe she'd just been blowing off steam because her rascal boyfriend had neglected to call her one weekend. Big deal. Maybe they'd kissed and made up, maybe she and Bob were down at Pop's Chocolate Shop now, sharing a malted. Sure. Easy to find out. All I had to do was call Evelyn up. With a half-clever story and enough brass-plated gall I could probably trick the truth out of her. Phone-phreaks and hackers deceive people over the phone all the time. It's called "social engineering." Social engineering is a very common practice in the underground, and almost magically effective. Human beings are almost always the weakest link in computer security. The simplest way to learn Things You Are Not Meant To Know is simply to call up and exploit the knowledgeable people. With social engineering, you use the bits of specialized knowledge you already have as a key, to manipulate people into believing that you are legitimate. You can then coax, flatter, or frighten them into revealing almost anything you want to know. Deceiving people (especially over the phone) is easy and fun. Exploiting their gullibility is very gratifying; it makes you feel very superior to them. If I'd been a malicious hacker on a trashing raid, I would now have Evelyn very much in my power. Given all this inside data, it wouldn't take much effort at all to invent a convincing lie. If I were ruthless enough, and jaded enough, and clever enough, this momentary indiscretion of hers-- maybe committed in tears, who knows--could cause her a whole world of confusion and grief. I didn't even have to have a MALICIOUS motive. Maybe I'd be "on her side," and call up Bob instead, and anonymously threaten to break both his kneecaps if he didn't take Evelyn out for a steak dinner pronto. It was still profoundly NONE OF MY BUSINESS. To have gotten this knowledge at all was a sordid act and to use it would be to inflict a sordid injury. To do all these awful things would require exactly zero high-tech expertise. All it would take was the willingness to do it and a certain amount of bent imagination. I went back downstairs. The hard-working FCIC, who had labored forty-five minutes over their schedule, were through for the day, and adjourned to the hotel bar. We all had a beer. I had a chat with a guy about "Isis," or rather IACIS, the International Association of Computer Investigation Specialists. They're into "computer forensics," the techniques of picking computer- systems apart without destroying vital evidence. IACIS, currently run out of Oregon, is comprised of investigators in the U.S., Canada, Taiwan and Ireland. "Taiwan and Ireland?" I said. Are TAIWAN and IRELAND really in the forefront of this stuff? Well not exactly, my informant admitted. They just happen to have been the first ones to have caught on by word of mouth. Still, the international angle counts, because this is obviously an international problem. Phone-lines go everywhere. There was a Mountie here from the Royal Canadian Mounted Police. He seemed to be having quite a good time. Nobody had flung this Canadian out because he might pose a foreign security risk. These are cyberspace cops. They still worry a lot about "jurisdictions," but mere geography is the least of their troubles. NASA had failed to show. NASA suffers a lot from computer intrusions, in particular from Australian raiders and a well-trumpeted Chaos Computer Club case, and in 1990 there was a brief press flurry when it was revealed that one of NASA's Houston branch-exchanges had been systematically ripped off by a gang of phone-phreaks. But the NASA guys had had their funding cut. They were stripping everything. Air Force OSI, its Office of Special Investigations, is the ONLY federal entity dedicated full-time to computer security. They'd been expected to show up in force, but some of them had cancelled--a Pentagon budget pinch. As the empties piled up, the guys began joshing around and telling war-stories. "These are cops," Thackeray said tolerantly. "If they're not talking shop they talk about women and beer." I heard the story about the guy who, asked for "a copy" of a computer disk, PHOTOCOPIED THE LABEL ON IT. He put the floppy disk onto the glass plate of a photocopier. The blast of static when the copier worked completely erased all the real information on the disk. Some other poor souls threw a whole bag of confiscated diskettes into the squad-car trunk next to the police radio. The powerful radio signal blasted them, too. We heard a bit about Dave Geneson, the first computer prosecutor, a mainframe-runner in Dade County, turned lawyer. Dave Geneson was one guy who had hit the ground running, a signal virtue in making the transition to computer-crime. It was generally agreed that it was easier to learn the world of computers first, then police or prosecutorial work. You could take certain computer people and train 'em to successful police work--but of course they had to have the COP MENTALITY. They had to have street smarts. Patience. Persistence. And discretion. You've got to make sure they're not hot-shots, show-offs, "cowboys." Most of the folks in the bar had backgrounds in military intelligence, or drugs, or homicide. It was rudely opined that "military intelligence" was a contradiction in terms, while even the grisly world of homicide was considered cleaner than drug enforcement. One guy had been 'way undercover doing dope-work in Europe for four years straight. "I'm almost recovered now," he said deadpan, with the acid black humor that is pure cop. "Hey, now I can say FUCKER without putting MOTHER in front of it." "In the cop world," another guy said earnestly, "everything is good and bad, black and white. In the computer world everything is gray." One guy--a founder of the FCIC, who'd been with the group since it was just the Colluquy--described his own introduction to the field. He'd been a Washington DC homicide guy called in on a "hacker" case. From the word "hacker," he naturally assumed he was on the trail of a knife-wielding marauder, and went to the computer center expecting blood and a body. When he finally figured out what was happening there (after loudly demanding, in vain, that the programmers "speak English"), he called headquarters and told them he was clueless about computers. They told him nobody else knew diddly either, and to get the hell back to work. So, he said, he had proceeded by comparisons. By analogy. By metaphor. "Somebody broke in to your computer, huh?" Breaking and entering; I can understand that. How'd he get in? "Over the phone-lines." Harassing phone-calls, I can understand that! What we need here is a tap and a trace! It worked. It was better than nothing. And it worked a lot faster when he got hold of another cop who'd done something similar. And then the two of them got another, and another, and pretty soon the Colluquy was a happening thing. It helped a lot that everybody seemed to know Carlton Fitzpatrick, the data-processing trainer in Glynco. The ice broke big-time in Memphis in '86. The Colluquy had attracted a bunch of new guys--Secret Service, FBI, military, other feds, heavy guys. Nobody wanted to tell anybody anything. They suspected that if word got back to the home office they'd all be fired. They passed an uncomfortably guarded afternoon. The formalities got them nowhere. But after the formal session was over, the organizers brought in a case of beer. As soon as the participants knocked it off with the bureaucratic ranks and turf-fighting, everything changed. "I bared my soul," one veteran reminisced proudly. By nightfall they were building pyramids of empty beer-cans and doing everything but composing a team fight song. FCIC were not the only computer-crime people around. There was DATTA (District Attorneys' Technology Theft Association), though they mostly specialized in chip theft, intellectual property, and black-market cases. There was HTCIA (High Tech Computer Investigators Association), also out in Silicon Valley, a year older than FCIC and featuring brilliant people like Donald Ingraham. There was LEETAC (Law Enforcement Electronic Technology Assistance Committee) in Florida, and computer-crime units in Illinois and Maryland and Texas and Ohio and Colorado and Pennsylvania. But these were local groups. FCIC were the first to really network nationally and on a federal level. FCIC people live on the phone lines. Not on bulletin board systems-- they know very well what boards are, and they know that boards aren't secure. Everyone in the FCIC has a voice-phone bill like you wouldn't believe. FCIC people have been tight with the telco people for a long time. Telephone cyberspace is their native habitat. FCIC has three basic sub-tribes: the trainers, the security people, and the investigators. That's why it's called an "Investigations Committee" with no mention of the term "computer-crime"--the dreaded "C-word." FCIC, officially, is "an association of agencies rather than individuals;" unofficially, this field is small enough that the influence of individuals and individual expertise is paramount. Attendance is by invitation only, and most everyone in FCIC considers himself a prophet without honor in his own house. Again and again I heard this, with different terms but identical sentiments. "I'd been sitting in the wilderness talking to myself." "I was totally isolated." "I was desperate." "FCIC is the best thing there is about computer crime in America." "FCIC is what really works." "This is where you hear real people telling you what's really happening out there, not just lawyers picking nits." "We taught each other everything we knew." The sincerity of these statements convinces me that this is true. FCIC is the real thing and it is invaluable. It's also very sharply at odds with the rest of the traditions and power structure in American law enforcement. There probably hasn't been anything around as loose and go-getting as the FCIC since the start of the U.S. Secret Service in the 1860s. FCIC people are living like twenty-first-century people in a twentieth-century environment, and while there's a great deal to be said for that, there's also a great deal to be said against it, and those against it happen to control the budgets. I listened to two FCIC guys from Jersey compare life histories. One of them had been a biker in a fairly heavy-duty gang in the 1960s. "Oh, did you know so-and-so?" said the other guy from Jersey. "Big guy, heavyset?" "Yeah, I knew him." "Yeah, he was one of ours. He was our plant in the gang." "Really? Wow! Yeah, I knew him. Helluva guy." Thackeray reminisced at length about being tear-gassed blind in the November 1969 antiwar protests in Washington Circle, covering them for her college paper. "Oh yeah, I was there," said another cop. "Glad to hear that tear gas hit somethin'. Haw haw haw." He'd been so blind himself, he confessed, that later that day he'd arrested a small tree. FCIC are an odd group, sifted out by coincidence and necessity, and turned into a new kind of cop. There are a lot of specialized cops in the world--your bunco guys, your drug guys, your tax guys, but the only group that matches FCIC for sheer isolation are probably the child-pornography people. Because they both deal with conspirators who are desperate to exchange forbidden data and also desperate to hide; and because nobody else in law enforcement even wants to hear about it. FCIC people tend to change jobs a lot. They tend not to get the equipment and training they want and need. And they tend to get sued quite often. As the night wore on and a band set up in the bar, the talk grew darker. Nothing ever gets done in government, someone opined, until there's a DISASTER. Computing disasters are awful, but there's no denying that they greatly help the credibility of FCIC people. The Internet Worm, for instance. "For years we'd been warning about that--but it's nothing compared to what's coming." They expect horrors, these people. They know that nothing will really get done until there is a horror. # Next day we heard an extensive briefing from a guy who'd been a computer cop, gotten into hot water with an Arizona city council, and now installed computer networks for a living (at a considerable rise in pay). He talked about pulling fiber-optic networks apart. Even a single computer, with enough peripherals, is a literal "network"--a bunch of machines all cabled together, generally with a complexity that puts stereo units to shame. FCIC people invent and publicize methods of seizing computers and maintaining their evidence. Simple things, sometimes, but vital rules of thumb for street cops, who nowadays often stumble across a busy computer in the midst of a drug investigation or a white-collar bust. For instance: Photograph the system before you touch it. Label the ends of all the cables before you detach anything. "Park" the heads on the disk drives before you move them. Get the diskettes. Don't put the diskettes in magnetic fields. Don't write on diskettes with ballpoint pens. Get the manuals. Get the printouts. Get the handwritten notes. Copy data before you look at it, and then examine the copy instead of the original. Now our lecturer distributed copied diagrams of a typical LAN or "Local Area Network", which happened to be out of Connecticut. ONE HUNDRED AND FIFTY-NINE desktop computers, each with its own peripherals. Three "file servers." Five "star couplers" each with thirty-two ports. One sixteen-port coupler off in the corner office. All these machines talking to each other, distributing electronic mail, distributing software, distributing, quite possibly, criminal evidence. All linked by high-capacity fiber-optic cable. A bad guy--cops talk a about "bad guys" --might be lurking on PC #47 lot or #123 and distributing his ill doings onto some dupe's "personal" machine in another office--or another floor--or, quite possibly, two or three miles away! Or, conceivably, the evidence might be "data-striped"--split up into meaningless slivers stored, one by one, on a whole crowd of different disk drives. The lecturer challenged us for solutions. I for one was utterly clueless. As far as I could figure, the Cossacks were at the gate; there were probably more disks in this single building than were seized during the entirety of Operation Sundevil. "Inside informant," somebody said. Right. There's always the human angle, something easy to forget when contemplating the arcane recesses of high technology. Cops are skilled at getting people to talk, and computer people, given a chair and some sustained attention, will talk about their computers till their throats go raw. There's a case on record of a single question-- "How'd you do it?"--eliciting a forty-five-minute videotaped confession from a computer criminal who not only completely incriminated himself but drew helpful diagrams. Computer people talk. Hackers BRAG. Phone-phreaks talk PATHOLOGICALLY--why else are they stealing phone-codes, if not to natter for ten hours straight to their friends on an opposite seaboard? Computer-literate people do in fact possess an arsenal of nifty gadgets and techniques that would allow them to conceal all kinds of exotic skullduggery, and if they could only SHUT UP about it, they could probably get away with all manner of amazing information-crimes. But that's just not how it works--or at least, that's not how it's worked SO FAR. Most every phone-phreak ever busted has swiftly implicated his mentors, his disciples, and his friends. Most every white-collar computer-criminal, smugly convinced that his clever scheme is bulletproof, swiftly learns otherwise when, for the first time in his life, an actual no-kidding policeman leans over, grabs the front of his shirt, looks him right in the eye and says: "All right, ASSHOLE--you and me are going downtown!" All the hardware in the world will not insulate your nerves from these actual real-life sensations of terror and guilt. Cops know ways to get from point A to point Z without thumbing through every letter in some smart-ass bad-guy's alphabet. Cops know how to cut to the chase. Cops know a lot of things other people don't know. Hackers know a lot of things other people don't know, too. Hackers know, for instance, how to sneak into your computer through the phone-lines. But cops can show up RIGHT ON YOUR DOORSTEP and carry off YOU and your computer in separate steel boxes. A cop interested in hackers can grab them and grill them. A hacker interested in cops has to depend on hearsay, underground legends, and what cops are willing to publicly reveal. And the Secret Service didn't get named "the SECRET Service" because they blab a lot. Some people, our lecturer informed us, were under the mistaken impression that it was "impossible" to tap a fiber-optic line. Well, he announced, he and his son had just whipped up a fiber-optic tap in his workshop at home. He passed it around the audience, along with a circuit-covered LAN plug-in card so we'd all recognize one if we saw it on a case. We all had a look. The tap was a classic "Goofy Prototype"--a thumb-length rounded metal cylinder with a pair of plastic brackets on it. From one end dangled three thin black cables, each of which ended in a tiny black plastic cap. When you plucked the safety-cap off the end of a cable, you could see the glass fiber-- no thicker than a pinhole. Our lecturer informed us that the metal cylinder was a "wavelength division multiplexer." Apparently, what one did was to cut the fiber-optic cable, insert two of the legs into the cut to complete the network again, and then read any passing data on the line by hooking up the third leg to some kind of monitor. Sounded simple enough. I wondered why nobody had thought of it before. I also wondered whether this guy's son back at the workshop had any teenage friends. We had a break. The guy sitting next to me was wearing a giveaway baseball cap advertising the Uzi submachine gun. We had a desultory chat about the merits of Uzis. Long a favorite of the Secret Service, it seems Uzis went out of fashion with the advent of the Persian Gulf War, our Arab allies taking some offense at Americans toting Israeli weapons. Besides, I was informed by another expert, Uzis jam. The equivalent weapon of choice today is the Heckler & Koch, manufactured in Germany. The guy with the Uzi cap was a forensic photographer. He also did a lot of photographic surveillance work in computer crime cases. He used to, that is, until the firings in Phoenix. He was now a private investigator and, with his wife, ran a photography salon specializing in weddings and portrait photos. At--one must repeat--a considerable rise in income. He was still FCIC. If you were FCIC, and you needed to talk to an expert about forensic photography, well, there he was, willing and able. If he hadn't shown up, people would have missed him. Our lecturer had raised the point that preliminary investigation of a computer system is vital before any seizure is undertaken. It's vital to understand how many machines are in there, what kinds there are, what kind of operating system they use, how many people use them, where the actual data itself is stored. To simply barge into an office demanding "all the computers" is a recipe for swift disaster. This entails some discreet inquiries beforehand. In fact, what it entails is basically undercover work. An intelligence operation. SPYING, not to put too fine a point on it. In a chat after the lecture, I asked an attendee whether "trashing" might work. I received a swift briefing on the theory and practice of "trash covers." Police "trash covers," like "mail covers" or like wiretaps, require the agreement of a judge. This obtained, the "trashing" work of cops is just like that of hackers, only more so and much better organized. So much so, I was informed, that mobsters in Phoenix make extensive use of locked garbage cans picked up by a specialty high-security trash company. In one case, a tiger team of Arizona cops had trashed a local residence for four months. Every week they showed up on the municipal garbage truck, disguised as garbagemen, and carried the contents of the suspect cans off to a shade tree, where they combed through the garbage--a messy task, especially considering that one of the occupants was undergoing kidney dialysis. All useful documents were cleaned, dried and examined. A discarded typewriter-ribbon was an especially valuable source of data, as its long one-strike ribbon of film contained the contents of every letter mailed out of the house. The letters were neatly retyped by a police secretary equipped with a large desk-mounted magnifying glass. There is something weirdly disquieting about the whole subject of "trashing"-- an unsuspected and indeed rather disgusting mode of deep personal vulnerability. Things that we pass by every day, that we take utterly for granted, can be exploited with so little work. Once discovered, the knowledge of these vulnerabilities tend to spread. Take the lowly subject of MANHOLE COVERS. The humble manhole cover reproduces many of the dilemmas of computer-security in miniature. Manhole covers are, of course, technological artifacts, access-points to our buried urban infrastructure. To the vast majority of us, manhole covers are invisible. They are also vulnerable. For many years now, the Secret Service has made a point of caulking manhole covers along all routes of the Presidential motorcade. This is, of course, to deter terrorists from leaping out of underground ambush or, more likely, planting remote-control car-smashing bombs beneath the street. Lately, manhole covers have seen more and more criminal exploitation, especially in New York City. Recently, a telco in New York City discovered that a cable television service had been sneaking into telco manholes and installing cable service alongside the phone-lines-- WITHOUT PAYING ROYALTIES. New York companies have also suffered a general plague of (a) underground copper cable theft; (b) dumping of garbage, including toxic waste, and (c) hasty dumping of murder victims. Industry complaints reached the ears of an innovative New England industrial-security company, and the result was a new product known as "the Intimidator," a thick titanium-steel bolt with a precisely machined head that requires a special device to unscrew. All these "keys" have registered serial numbers kept on file with the manufacturer. There are now some thousands of these "Intimidator" bolts being sunk into American pavements wherever our President passes, like some macabre parody of strewn roses. They are also spreading as fast as steel dandelions around US military bases and many centers of private industry. Quite likely it has never occurred to you to peer under a manhole cover, perhaps climb down and walk around down there with a flashlight, just to see what it's like. Formally speaking, this might be trespassing, but if you didn't hurt anything, and didn't make an absolute habit of it, nobody would really care. The freedom to sneak under manholes was likely a freedom you never intended to exercise. You now are rather less likely to have that freedom at all. You may never even have missed it until you read about it here, but if you're in New York City it's gone, and elsewhere it's likely going. This is one of the things that crime, and the reaction to crime, does to us. The tenor of the meeting now changed as the Electronic Frontier Foundation arrived. The EFF, whose personnel and history will be examined in detail in the next chapter, are a pioneering civil liberties group who arose in direct response to the Hacker Crackdown of 1990. Now Mitchell Kapor, the Foundation's president, and Michael Godwin, its chief attorney, were confronting federal law enforcement MANO A MANO for the first time ever. Ever alert to the manifold uses of publicity, Mitch Kapor and Mike Godwin had brought their own journalist in tow: Robert Draper, from Austin, whose recent well-received book about ROLLING STONE magazine was still on the stands. Draper was on assignment for TEXAS MONTHLY. The Steve Jackson/EFF civil lawsuit against the Chicago Computer Fraud and Abuse Task Force was a matter of considerable regional interest in Texas. There were now two Austinite journalists here on the case. In fact, counting Godwin (a former Austinite and former journalist) there were three of us. Lunch was like Old Home Week. Later, I took Draper up to my hotel room. We had a long frank talk about the case, networking earnestly like a miniature freelance-journo version of the FCIC: privately confessing the numerous blunders of journalists covering the story, and trying hard to figure out who was who and what the hell was really going on out there. I showed Draper everything I had dug out of the Hilton trashcan. We pondered the ethics of "trashing" for a while, and agreed that they were dismal. We also agreed that finding a SPRINT bill on your first time out was a heck of a coincidence. First I'd "trashed"--and now, mere hours later, I'd bragged to someone else. Having entered the lifestyle of hackerdom, I was now, unsurprisingly, following its logic. Having discovered something remarkable through a surreptitious action, I of course HAD to "brag," and to drag the passing Draper into my iniquities. I felt I needed a witness. Otherwise nobody would have believed what I'd discovered. . . . Back at the meeting, Thackeray cordially, if rather tentatively, introduced Kapor and Godwin to her colleagues. Papers were distributed. Kapor took center stage. The brilliant Bostonian high-tech entrepreneur, normally the hawk in his own administration and quite an effective public speaker, seemed visibly nervous, and frankly admitted as much. He began by saying he consided computer-intrusion to be morally wrong, and that the EFF was not a "hacker defense fund," despite what had appeared in print. Kapor chatted a bit about the basic motivations of his group, emphasizing their good faith and willingness to listen and seek common ground with law enforcement--when, er, possible. Then, at Godwin's urging, Kapor suddenly remarked that EFF's own Internet machine had been "hacked" recently, and that EFF did not consider this incident amusing. After this surprising confession, things began to loosen up quite rapidly. Soon Kapor was fielding questions, parrying objections, challenging definitions, and juggling paradigms with something akin to his usual gusto. Kapor seemed to score quite an effect with his shrewd and skeptical analysis of the merits of telco "Caller-ID" services. (On this topic, FCIC and EFF have never been at loggerheads, and have no particular established earthworks to defend.) Caller-ID has generally been promoted as a privacy service for consumers, a presentation Kapor described as a "smokescreen," the real point of Caller-ID being to ALLOW CORPORATE CUSTOMERS TO BUILD EXTENSIVE COMMERCIAL DATABASES ON EVERYBODY WHO PHONES OR FAXES THEM. Clearly, few people in the room had considered this possibility, except perhaps for two late-arrivals from US WEST RBOC security, who chuckled nervously. Mike Godwin then made an extensive presentation on "Civil Liberties Implications of Computer Searches and Seizures." Now, at last, we were getting to the real nitty-gritty here, real political horse-trading. The audience listened with close attention, angry mutters rising occasionally: "He's trying to teach us our jobs!" "We've been thinking about this for years! We think about these issues every day!" "If I didn't seize the works, I'd be sued by the guy's victims!" "I'm violating the law if I leave ten thousand disks full of illegal PIRATED SOFTWARE and STOLEN CODES!" "It's our job to make sure people don't trash the Constitution-- we're the DEFENDERS of the Constitution!" "We seize stuff when we know it will be forfeited anyway as restitution for the victim!" "If it's forfeitable, then don't get a search warrant, get a forfeiture warrant," Godwin suggested coolly. He further remarked that most suspects in computer crime don't WANT to see their computers vanish out the door, headed God knew where, for who knows how long. They might not mind a search, even an extensive search, but they want their machines searched on-site. "Are they gonna feed us?" somebody asked sourly. "How about if you take copies of the data?" Godwin parried. "That'll never stand up in court." "Okay, you make copies, give THEM the copies, and take the originals." Hmmm. Godwin championed bulletin-board systems as repositories of First Amendment protected free speech. He complained that federal computer-crime training manuals gave boards a bad press, suggesting that they are hotbeds of crime haunted by pedophiles and crooks, whereas the vast majority of the nation's thousands of boards are completely innocuous, and nowhere near so romantically suspicious. People who run boards violently resent it when their systems are seized, and their dozens (or hundreds) of users look on in abject horror. Their rights of free expression are cut short. Their right to associate with other people is infringed. And their privacy is violated as their private electronic mail becomes police property. Not a soul spoke up to defend the practice of seizing boards. The issue passed in chastened silence. Legal principles aside-- (and those principles cannot be settled without laws passed or court precedents)--seizing bulletin boards has become public-relations poison for American computer police. And anyway, it's not entirely necessary. If you're a cop, you can get 'most everything you need from a pirate board, just by using an inside informant. Plenty of vigilantes--well, CONCERNED CITIZENS--will inform police the moment they see a pirate board hit their area (and will tell the police all about it, in such technical detail, actually, that you kinda wish they'd shut up). They will happily supply police with extensive downloads or printouts. It's IMPOSSIBLE to keep this fluid electronic information out of the hands of police. Some people in the electronic community become enraged at the prospect of cops "monitoring" bulletin boards. This does have touchy aspects, as Secret Service people in particular examine bulletin boards with some regularity. But to expect electronic police to be deaf dumb and blind in regard to this particular medium rather flies in the face of common sense. Police watch television, listen to radio, read newspapers and magazines; why should the new medium of boards be different? Cops can exercise the same access to electronic information as everybody else. As we have seen, quite a few computer police maintain THEIR OWN bulletin boards, including anti-hacker "sting" boards, which have generally proven quite effective. As a final clincher, their Mountie friends in Canada (and colleagues in Ireland and Taiwan) don't have First Amendment or American constitutional restrictions, but they do have phone lines, and can call any bulletin board in America whenever they please. The same technological determinants that play into the hands of hackers, phone phreaks and software pirates can play into the hands of police. "Technological determinants" don't have ANY human allegiances. They're not black or white, or Establishment or Underground, or pro-or-anti anything. Godwin complained at length about what he called "the Clever Hobbyist hypothesis" --the assumption that the "hacker" you're busting is clearly a technical genius, and must therefore by searched with extreme thoroughness. So: from the law's point of view, why risk missing anything? Take the works. Take the guy's computer. Take his books. Take his notebooks. Take the electronic drafts of his love letters. Take his Walkman. Take his wife's computer. Take his dad's computer. Take his kid sister's computer. Take his employer's computer. Take his compact disks-- they MIGHT be CD-ROM disks, cunningly disguised as pop music. Take his laser printer--he might have hidden something vital in the printer's 5meg of memory. Take his software manuals and hardware documentation. Take his science-fiction novels and his simulation- gaming books. Take his Nintendo Game-Boy and his Pac-Man arcade game. Take his answering machine, take his telephone out of the wall. Take anything remotely suspicious. Godwin pointed out that most "hackers" are not, in fact, clever genius hobbyists. Quite a few are crooks and grifters who don't have much in the way of technical sophistication; just some rule-of-thumb rip-off techniques. The same goes for most fifteen-year-olds who've downloaded a code-scanning program from a pirate board. There's no real need to seize everything in sight. It doesn't require an entire computer system and ten thousand disks to prove a case in court. What if the computer is the instrumentality of a crime? someone demanded. Godwin admitted quietly that the doctrine of seizing the instrumentality of a crime was pretty well established in the American legal system. The meeting broke up. Godwin and Kapor had to leave. Kapor was testifying next morning before the Massachusetts Department Of Public Utility, about ISDN narrowband wide-area networking. As soon as they were gone, Thackeray seemed elated. She had taken a great risk with this. Her colleagues had not, in fact, torn Kapor and Godwin's heads off. She was very proud of them, and told them so. "Did you hear what Godwin said about INSTRUMENTALITY OF A CRIME?" she exulted, to nobody in particular. "Wow, that means MITCH ISN'T GOING TO SUE ME." # America's computer police are an interesting group. As a social phenomenon they are far more interesting, and far more important, than teenage phone phreaks and computer hackers. First, they're older and wiser; not dizzy hobbyists with leaky morals, but seasoned adult professionals with all the responsibilities of public service. And, unlike hackers, they possess not merely TECHNICAL power alone, but heavy-duty legal and social authority. And, very interestingly, they are just as much at sea in cyberspace as everyone else. They are not happy about this. Police are authoritarian by nature, and prefer to obey rules and precedents. (Even those police who secretly enjoy a fast ride in rough territory will soberly disclaim any "cowboy" attitude.) But in cyberspace there ARE no rules and precedents. They are groundbreaking pioneers, Cyberspace Rangers, whether they like it or not. In my opinion, any teenager enthralled by computers, fascinated by the ins and outs of computer security, and attracted by the lure of specialized forms of knowledge and power, would do well to forget all about "hacking" and set his (or her) sights on becoming a fed. Feds can trump hackers at almost every single thing hackers do, including gathering intelligence, undercover disguise, trashing, phone-tapping, building dossiers, networking, and infiltrating computer systems--CRIMINAL computer systems. Secret Service agents know more about phreaking, coding and carding than most phreaks can find out in years, and when it comes to viruses, break-ins, software bombs and trojan horses, Feds have direct access to red-hot confidential information that is only vague rumor in the underground. And if it's an impressive public rep you're after, there are few people in the world who can be so chillingly impressive as a well-trained, well-armed United States Secret Service agent. Of course, a few personal sacrifices are necessary in order to obtain that power and knowledge. First, you'll have the galling discipline of belonging to a large organization; but the world of computer crime is still so small, and so amazingly fast-moving, that it will remain spectacularly fluid for years to come. The second sacrifice is that you'll have to give up ripping people off. This is not a great loss. Abstaining from the use of illegal drugs, also necessary, will be a boon to your health. A career in computer security is not a bad choice for a young man or woman today. The field will almost certainly expand drastically in years to come. If you are a teenager today, by the time you become a professional, the pioneers you have read about in this book will be the grand old men and women of the field, swamped by their many disciples and successors. Of course, some of them, like William P. Wood of the 1865 Secret Service, may well be mangled in the whirring machinery of legal controversy; but by the time you enter the computer-crime field, it may have stabilized somewhat, while remaining entertainingly challenging. But you can't just have a badge. You have to win it. First, there's the federal law enforcement training. And it's hard--it's a challenge. A real challenge--not for wimps and rodents. Every Secret Service agent must complete gruelling courses at the Federal Law Enforcement Training Center. (In fact, Secret Service agents are periodically re-trained during their entire careers.) In order to get a glimpse of what this might be like, I myself travelled to FLETC. # The Federal Law Enforcement Training Center is a 1500-acre facility on Georgia's Atlantic coast. It's a milieu of marshgrass, seabirds, damp, clinging sea-breezes, palmettos, mosquitos, and bats. Until 1974, it was a Navy Air Base, and still features a working runway, and some WWII vintage blockhouses and officers' quarters. The Center has since benefitted by a forty-million-dollar retrofit, but there's still enough forest and swamp on the facility for the Border Patrol to put in tracking practice. As a town, "Glynco" scarcely exists. The nearest real town is Brunswick, a few miles down Highway 17, where I stayed at the aptly named Marshview Holiday Inn. I had Sunday dinner at a seafood restaurant called "Jinright's," where I feasted on deep-fried alligator tail. This local favorite was a heaped basket of bite-sized chunks of white, tender, almost fluffy reptile meat, steaming in a peppered batter crust. Alligator makes a culinary experience that's hard to forget, especially when liberally basted with homemade cocktail sauce from a Jinright squeeze-bottle. The crowded clientele were tourists, fishermen, local black folks in their Sunday best, and white Georgian locals who all seemed to bear an uncanny resemblance to Georgia humorist Lewis Grizzard. The 2,400 students from 75 federal agencies who make up the FLETC population scarcely seem to make a dent in the low-key local scene. The students look like tourists, and the teachers seem to have taken on much of the relaxed air of the Deep South. My host was Mr. Carlton Fitzpatrick, the Program Coordinator of the Financial Fraud Institute. Carlton Fitzpatrick is a mustached, sinewy, well-tanned Alabama native somewhere near his late forties, with a fondness for chewing tobacco, powerful computers, and salty, down-home homilies. We'd met before, at FCIC in Arizona. The Financial Fraud Institute is one of the nine divisions at FLETC. Besides Financial Fraud, there's Driver & Marine, Firearms, and Physical Training. These are specialized pursuits. There are also five general training divisions: Basic Training, Operations, Enforcement Techniques, Legal Division, and Behavioral Science. Somewhere in this curriculum is everything necessary to turn green college graduates into federal agents. First they're given ID cards. Then they get the rather miserable-looking blue coveralls known as "smurf suits." The trainees are assigned a barracks and a cafeteria, and immediately set on FLETC's bone-grinding physical training routine. Besides the obligatory daily jogging--(the trainers run up danger flags beside the track when the humidity rises high enough to threaten heat stroke)-- here's the Nautilus machines, the martial arts, the survival skills. . . . The eighteen federal agencies who maintain on-site academies at FLETC employ a wide variety of specialized law enforcement units, some of them rather arcane. There's Border Patrol, IRS Criminal Investigation Division, Park Service, Fish and Wildlife, Customs, Immigration, Secret Service and the Treasury's uniformed subdivisions. . . . If you're a federal cop and you don't work for the FBI, you train at FLETC. This includes people as apparently obscure as the agents of the Railroad Retirement Board Inspector General. Or the Tennessee Valley Authority Police, who are in fact federal police officers, and can and do arrest criminals on the federal property of the Tennessee Valley Authority. And then there are the computer-crime people. All sorts, all backgrounds. Mr. Fitzpatrick is not jealous of his specialized knowledge. Cops all over, in every branch of service, may feel a need to learn what he can teach. Backgrounds don't matter much. Fitzpatrick himself was originally a Border Patrol veteran, then became a Border Patrol instructor at FLETC. His Spanish is still fluent--but he found himself strangely fascinated when the first computers showed up at the Training Center. Fitzpatrick did have a background in electrical engineering, and though he never considered himself a computer hacker, he somehow found himself writing useful little programs for this new and promising gizmo. He began looking into the general subject of computers and crime, reading Donn Parker's books and articles, keeping an ear cocked for war stories, useful insights from the field, the up-and-coming people of the local computer-crime and high-technology units. . . . Soon he got a reputation around FLETC as the resident "computer expert," and that reputation alone brought him more exposure, more experience-- until one day he looked around, and sure enough he WAS a federal computer-crime expert. In fact, this unassuming, genial man may be THE federal computer-crime expert. There are plenty of very good computer people, and plenty of very good federal investigators, but the area where these worlds of expertise overlap is very slim. And Carlton Fitzpatrick has been right at the center of that since 1985, the first year of the Colluquy, a group which owes much to his influence. He seems quite at home in his modest, acoustic-tiled office, with its Ansel Adams-style Western photographic art, a gold-framed Senior Instructor Certificate, and a towering bookcase crammed with three-ring binders with ominous titles such as Datapro Reports on Information Security and CFCA Telecom Security '90. The phone rings every ten minutes; colleagues show up at the door to chat about new developments in locksmithing or to shake their heads over the latest dismal developments in the BCCI global banking scandal. Carlton Fitzpatrick is a fount of computer-crime war-stories, related in an acerbic drawl. He tells me the colorful tale of a hacker caught in California some years back. He'd been raiding systems, typing code without a detectable break, for twenty, twenty-four, thirty-six hours straight. Not just logged on--TYPING. Investigators were baffled. Nobody could do that. Didn't he have to go to the bathroom? Was it some kind of automatic keyboard-whacking device that could actually type code? A raid on the suspect's home revealed a situation of astonishing squalor. The hacker turned out to be a Pakistani computer-science student who had flunked out of a California university. He'd gone completely underground as an illegal electronic immigrant, and was selling stolen phone-service to stay alive. The place was not merely messy and dirty, but in a state of psychotic disorder. Powered by some weird mix of culture shock, computer addiction, and amphetamines, the suspect had in fact been sitting in front of his computer for a day and a half straight, with snacks and drugs at hand on the edge of his desk and a chamber-pot under his chair. Word about stuff like this gets around in the hacker-tracker community. Carlton Fitzpatrick takes me for a guided tour by car around the FLETC grounds. One of our first sights is the biggest indoor firing range in the world. There are federal trainees in there, Fitzpatrick assures me politely, blasting away with a wide variety of automatic weapons: Uzis, Glocks, AK-47s. . . . He's willing to take me inside. I tell him I'm sure that's really interesting, but I'd rather see his computers. Carlton Fitzpatrick seems quite surprised and pleased. I'm apparently the first journalist he's ever seen who has turned down the shooting gallery in favor of microchips. Our next stop is a favorite with touring Congressmen: the three-mile long FLETC driving range. Here trainees of the Driver & Marine Division are taught high-speed pursuit skills, setting and breaking road-blocks, diplomatic security driving for VIP limousines. . . . A favorite FLETC pastime is to strap a passing Senator into the passenger seat beside a Driver & Marine trainer, hit a hundred miles an hour, then take it right into "the skid-pan," a section of greased track where two tons of Detroit iron can whip and spin like a hockey puck. Cars don't fare well at FLETC. First they're rifled again and again for search practice. Then they do 25,000 miles of high-speed pursuit training; they get about seventy miles per set of steel-belted radials. Then it's off to the skid pan, where sometimes they roll and tumble headlong in the grease. When they're sufficiently grease-stained, dented, and creaky, they're sent to the roadblock unit, where they're battered without pity. And finally then they're sacrificed to the Bureau of Alcohol, Tobacco and Firearms, whose trainees learn the ins and outs of car-bomb work by blowing them into smoking wreckage. There's a railroad box-car on the FLETC grounds, and a large grounded boat, and a propless plane; all training-grounds for searches. The plane sits forlornly on a patch of weedy tarmac next to an eerie blockhouse known as the "ninja compound," where anti-terrorism specialists practice hostage rescues. As I gaze on this creepy paragon of modern low-intensity warfare, my nerves are jangled by a sudden staccato outburst of automatic weapons fire, somewhere in the woods to my right. "Nine-millimeter," Fitzpatrick judges calmly. Even the eldritch ninja compound pales somewhat compared to the truly surreal area known as "the raid-houses." This is a street lined on both sides with nondescript concrete-block houses with flat pebbled roofs. They were once officers' quarters. Now they are training grounds. The first one to our left, Fitzpatrick tells me, has been specially adapted for computer search-and-seizure practice. Inside it has been wired for video from top to bottom, with eighteen pan-and-tilt remotely controlled videocams mounted on walls and in corners. Every movement of the trainee agent is recorded live by teachers, for later taped analysis. Wasted movements, hesitations, possibly lethal tactical mistakes--all are gone over in detail. Perhaps the weirdest single aspect of this building is its front door, scarred and scuffed all along the bottom, from the repeated impact, day after day, of federal shoe-leather. Down at the far end of the row of raid-houses some people are practicing a murder. We drive by slowly as some very young and rather nervous-looking federal trainees interview a heavyset bald man on the raid-house lawn. Dealing with murder takes a lot of practice; first you have to learn to control your own instinctive disgust and panic, then you have to learn to control the reactions of a nerve-shredded crowd of civilians, some of whom may have just lost a loved one, some of whom may be murderers-- quite possibly both at once. A dummy plays the corpse. The roles of the bereaved, the morbidly curious, and the homicidal are played, for pay, by local Georgians: waitresses, musicians, most anybody who needs to moonlight and can learn a script. These people, some of whom are FLETC regulars year after year, must surely have one of the strangest jobs in the world. Something about the scene: "normal" people in a weird situation, standing around talking in bright Georgia sunshine, unsuccessfully pretending that something dreadful has gone on, while a dummy lies inside on faked bloodstains. . . . While behind this weird masquerade, like a nested set of Russian dolls, are grim future realities of real death, real violence, real murders of real people, that these young agents will really investigate, many times during their careers. . . . Over and over. . . . Will those anticipated murders look like this, feel like this--not as "real" as these amateur actors are trying to make it seem, but both as "real," and as numbingly unreal, as watching fake people standing around on a fake lawn? Something about this scene unhinges me. It seems nightmarish to me, Kafkaesque. I simply don't know how to take it; my head is turned around; I don't know whether to laugh, cry, or just shudder. When the tour is over, Carlton Fitzpatrick and I talk about computers. For the first time cyberspace seems like quite a comfortable place. It seems very real to me suddenly, a place where I know what I'm talking about, a place I'm used to. It's real. "Real." Whatever. Carlton Fitzpatrick is the only person I've met in cyberspace circles who is happy with his present equipment. He's got a 5 Meg RAM PC with a 112 meg hard disk; a 660 meg's on the way. He's got a Compaq 386 desktop, and a Zenith 386 laptop with 120 meg. Down the hall is a NEC Multi-Sync 2A with a CD-ROM drive and a 9600 baud modem with four com-lines. There's a training minicomputer, and a 10-meg local mini just for the Center, and a lab-full of student PC clones and half-a-dozen Macs or so. There's a Data General MV 2500 with 8 meg on board and a 370 meg disk. Fitzpatrick plans to run a UNIX board on the Data General when he's finished beta-testing the software for it, which he wrote himself. It'll have E-mail features, massive files on all manner of computer-crime and investigation procedures, and will follow the computer-security specifics of the Department of Defense "Orange Book." He thinks it will be the biggest BBS in the federal government. Will it have Phrack on it? I ask wryly. Sure, he tells me. Phrack, TAP, Computer Underground Digest, all that stuff. With proper disclaimers, of course. I ask him if he plans to be the sysop. Running a system that size is very time-consuming, and Fitzpatrick teaches two three-hour courses every day. No, he says seriously, FLETC has to get its money worth out of the instructors. He thinks he can get a local volunteer to do it, a high-school student. He says a bit more, something I think about an Eagle Scout law-enforcement liaison program, but my mind has rocketed off in disbelief. "You're going to put a TEENAGER in charge of a federal security BBS?" I'm speechless. It hasn't escaped my notice that the FLETC Financial Fraud Institute is the ULTIMATE hacker-trashing target; there is stuff in here, stuff of such utter and consummate cool by every standard of the digital underground. . . . I imagine the hackers of my acquaintance, fainting dead-away from forbidden-knowledge greed-fits, at the mere prospect of cracking the superultra top-secret computers used to train the Secret Service in computer-crime. . . . "Uhm, Carlton," I babble, "I'm sure he's a really nice kid and all, but that's a terrible temptation to set in front of somebody who's, you know, into computers and just starting out. . . ." "Yeah," he says, "that did occur to me." For the first time I begin to suspect that he's pulling my leg. He seems proudest when he shows me an ongoing project called JICC, Joint Intelligence Control Council. It's based on the services provided by EPIC, the El Paso Intelligence Center, which supplies data and intelligence to the Drug Enforcement Administration, the Customs Service, the Coast Guard, and the state police of the four southern border states. Certain EPIC files can now be accessed by drug-enforcement police of Central America, South America and the Caribbean, who can also trade information among themselves. Using a telecom program called "White Hat," written by two brothers named Lopez from the Dominican Republic, police can now network internationally on inexpensive PCs. Carlton Fitzpatrick is teaching a class of drug-war agents from the Third World, and he's very proud of their progress. Perhaps soon the sophisticated smuggling networks of the Medellin Cartel will be matched by a sophisticated computer network of the Medellin Cartel's sworn enemies. They'll track boats, track contraband, track the international drug-lords who now leap over borders with great ease, defeating the police through the clever use of fragmented national jurisdictions. JICC and EPIC must remain beyond the scope of this book. They seem to me to be very large topics fraught with complications that I am not fit to judge. I do know, however, that the international, computer-assisted networking of police, across national boundaries, is something that Carlton Fitzpatrick considers very important, a harbinger of a desirable future. I also know that networks by their nature ignore physical boundaries. And I also know that where you put communications you put a community, and that when those communities become self-aware they will fight to preserve themselves and to expand their influence. I make no judgements whether this is good or bad. It's just cyberspace; it's just the way things are. I asked Carlton Fitzpatrick what advice he would have for a twenty-year-old who wanted to shine someday in the world of electronic law enforcement. He told me that the number one rule was simply not to be scared of computers. You don't need to be an obsessive "computer weenie," but you mustn't be buffaloed just because some machine looks fancy. The advantages computers give smart crooks are matched by the advantages they give smart cops. Cops in the future will have to enforce the law "with their heads, not their holsters." Today you can make good cases without ever leaving your office. In the future, cops who resist the computer revolution will never get far beyond walking a beat. I asked Carlton Fitzpatrick if he had some single message for the public; some single thing that he would most like the American public to know about his work. He thought about it while. "Yes," he said finally. "TELL me the rules, and I'll TEACH those rules!" He looked me straight in the eye. "I do the best that I can." PART FOUR: THE CIVIL LIBERTARIANS The story of the Hacker Crackdown, as we have followed it thus far, has been technological, subcultural, criminal and legal. The story of the Civil Libertarians, though it partakes of all those other aspects, is profoundly and thoroughly POLITICAL. In 1990, the obscure, long-simmering struggle over the ownership and nature of cyberspace became loudly and irretrievably public. People from some of the oddest corners of American society suddenly found themselves public figures. Some of these people found this situation much more than they had ever bargained for. They backpedalled, and tried to retreat back to the mandarin obscurity of their cozy subcultural niches. This was generally to prove a mistake. But the civil libertarians seized the day in 1990. They found themselves organizing, propagandizing, podium-pounding, persuading, touring, negotiating, posing for publicity photos, submitting to interviews, squinting in the limelight as they tried a tentative, but growingly sophisticated, buck-and-wing upon the public stage. It's not hard to see why the civil libertarians should have this competitive advantage. The hackers of the digital underground are an hermetic elite. They find it hard to make any remotely convincing case for their actions in front of the general public. Actually, hackers roundly despise the "ignorant" public, and have never trusted the judgement of "the system." Hackers do propagandize, but only among themselves, mostly in giddy, badly spelled manifestos of class warfare, youth rebellion or naive techie utopianism. Hackers must strut and boast in order to establish and preserve their underground reputations. But if they speak out too loudly and publicly, they will break the fragile surface-tension of the underground, and they will be harrassed or arrested. Over the longer term, most hackers stumble, get busted, get betrayed, or simply give up. As a political force, the digital underground is hamstrung. The telcos, for their part, are an ivory tower under protracted seige. They have plenty of money with which to push their calculated public image, but they waste much energy and goodwill attacking one another with slanderous and demeaning ad campaigns. The telcos have suffered at the hands of politicians, and, like hackers, they don't trust the public's judgement. And this distrust may be well-founded. Should the general public of the high-tech 1990s come to understand its own best interests in telecommunications, that might well pose a grave threat to the specialized technical power and authority that the telcos have relished for over a century. The telcos do have strong advantages: loyal employees, specialized expertise, influence in the halls of power, tactical allies in law enforcement, and unbelievably vast amounts of money. But politically speaking, they lack genuine grassroots support; they simply don't seem to have many friends. Cops know a lot of things other people don't know. But cops willingly reveal only those aspects of their knowledge that they feel will meet their institutional purposes and further public order. Cops have respect, they have responsibilities, they have power in the streets and even power in the home, but cops don't do particularly well in limelight. When pressed, they will step out in the public gaze to threaten bad-guys, or to cajole prominent citizens, or perhaps to sternly lecture the naive and misguided. But then they go back within their time-honored fortress of the station-house, the courtroom and the rule-book. The electronic civil libertarians, however, have proven to be born political animals. They seemed to grasp very early on the postmodern truism that communication is power. Publicity is power. Soundbites are power. The ability to shove one's issue onto the public agenda--and KEEP IT THERE--is power. Fame is power. Simple personal fluency and eloquence can be power, if you can somehow catch the public's eye and ear. The civil libertarians had no monopoly on "technical power"-- though they all owned computers, most were not particularly advanced computer experts. They had a good deal of money, but nowhere near the earthshaking wealth and the galaxy of resources possessed by telcos or federal agencies. They had no ability to arrest people. They carried out no phreak and hacker covert dirty-tricks. But they really knew how to network. Unlike the other groups in this book, the civil libertarians have operated very much in the open, more or less right in the public hurly-burly. They have lectured audiences galore and talked to countless journalists, and have learned to refine their spiels. They've kept the cameras clicking, kept those faxes humming, swapped that email, run those photocopiers on overtime, licked envelopes and spent small fortunes on airfare and long-distance. In an information society, this open, overt, obvious activity has proven to be a profound advantage. In 1990, the civil libertarians of cyberspace assembled out of nowhere in particular, at warp speed. This "group" (actually, a networking gaggle of interested parties which scarcely deserves even that loose term) has almost nothing in the way of formal organization. Those formal civil libertarian organizations which did take an interest in cyberspace issues, mainly the Computer Professionals for Social Responsibility and the American Civil Liberties Union, were carried along by events in 1990, and acted mostly as adjuncts, underwriters or launching-pads. The civil libertarians nevertheless enjoyed the greatest success of any of the groups in the Crackdown of 1990. At this writing, their future looks rosy and the political initiative is firmly in their hands. This should be kept in mind as we study the highly unlikely lives and lifestyles of the people who actually made this happen. # In June 1989, Apple Computer, Inc., of Cupertino, California, had a problem. Someone had illicitly copied a small piece of Apple's proprietary software, software which controlled an internal chip driving the Macintosh screen display. This Color QuickDraw source code was a closely guarded piece of Apple's intellectual property. Only trusted Apple insiders were supposed to possess it. But the "NuPrometheus League" wanted things otherwise. This person (or persons) made several illicit copies of this source code, perhaps as many as two dozen. He (or she, or they) then put those illicit floppy disks into envelopes and mailed them to people all over America: people in the computer industry who were associated with, but not directly employed by, Apple Computer. The NuPrometheus caper was a complex, highly ideological, and very hacker-like crime. Prometheus, it will be recalled, stole the fire of the Gods and gave this potent gift to the general ranks of downtrodden mankind. A similar god-in-the-manger attitude was implied for the corporate elite of Apple Computer, while the "Nu" Prometheus had himself cast in the role of rebel demigod. The illicitly copied data was given away for free. The new Prometheus, whoever he was, escaped the fate of the ancient Greek Prometheus, who was chained to a rock for centuries by the vengeful gods while an eagle tore and ate his liver. On the other hand, NuPrometheus chickened out somewhat by comparison with his role model. The small chunk of Color QuickDraw code he had filched and replicated was more or less useless to Apple's industrial rivals (or, in fact, to anyone else). Instead of giving fire to mankind, it was more as if NuPrometheus had photocopied the schematics for part of a Bic lighter. The act was not a genuine work of industrial espionage. It was best interpreted as a symbolic, deliberate slap in the face for the Apple corporate heirarchy. Apple's internal struggles were well-known in the industry. Apple's founders, Jobs and Wozniak, had both taken their leave long since. Their raucous core of senior employees had been a barnstorming crew of 1960s Californians, many of them markedly less than happy with the new button-down multimillion dollar regime at Apple. Many of the programmers and developers who had invented the Macintosh model in the early 1980s had also taken their leave of the company. It was they, not the current masters of Apple's corporate fate, who had invented the stolen Color QuickDraw code. The NuPrometheus stunt was well-calculated to wound company morale. Apple called the FBI. The Bureau takes an interest in high-profile intellectual-property theft cases, industrial espionage and theft of trade secrets. These were likely the right people to call, and rumor has it that the entities responsible were in fact discovered by the FBI, and then quietly squelched by Apple management. NuPrometheus was never publicly charged with a crime, or prosecuted, or jailed. But there were no further illicit releases of Macintosh internal software. Eventually the painful issue of NuPrometheus was allowed to fade. In the meantime, however, a large number of puzzled bystanders found themselves entertaining surprise guests from the FBI. One of these people was John Perry Barlow. Barlow is a most unusual man, difficult to describe in conventional terms. He is perhaps best known as a songwriter for the Grateful Dead, for he composed lyrics for "Hell in a Bucket," "Picasso Moon," "Mexicali Blues," "I Need a Miracle," and many more; he has been writing for the band since 1970. Before we tackle the vexing question as to why a rock lyricist should be interviewed by the FBI in a computer-crime case, it might be well to say a word or two about the Grateful Dead. The Grateful Dead are perhaps the most successful and long-lasting of the numerous cultural emanations from the Haight-Ashbury district of San Francisco, in the glory days of Movement politics and lysergic transcendance. The Grateful Dead are a nexus, a veritable whirlwind, of applique decals, psychedelic vans, tie-dyed T-shirts, earth-color denim, frenzied dancing and open and unashamed drug use. The symbols, and the realities, of Californian freak power surround the Grateful Dead like knotted macrame. The Grateful Dead and their thousands of Deadhead devotees are radical Bohemians. This much is widely understood. Exactly what this implies in the 1990s is rather more problematic. The Grateful Dead are among the world's most popular and wealthy entertainers: number 20, according to Forbes magazine, right between M.C. Hammer and Sean Connery. In 1990, this jeans-clad group of purported raffish outcasts earned seventeen million dollars. They have been earning sums much along this line for quite some time now. And while the Dead are not investment bankers or three-piece-suit tax specialists--they are, in point of fact, hippie musicians-- this money has not been squandered in senseless Bohemian excess. The Dead have been quietly active for many years, funding various worthy activities in their extensive and widespread cultural community. The Grateful Dead are not conventional players in the American power establishment. They nevertheless are something of a force to be reckoned with. They have a lot of money and a lot of friends in many places, both likely and unlikely. The Dead may be known for back-to-the-earth environmentalist rhetoric, but this hardly makes them anti-technological Luddites. On the contrary, like most rock musicians, the Grateful Dead have spent their entire adult lives in the company of complex electronic equipment. They have funds to burn on any sophisticated tool and toy that might happen to catch their fancy. And their fancy is quite extensive. The Deadhead community boasts any number of recording engineers, lighting experts, rock video mavens, electronic technicians of all descriptions. And the drift goes both ways. Steve Wozniak, Apple's co-founder, used to throw rock festivals. Silicon Valley rocks out. These are the 1990s, not the 1960s. Today, for a surprising number of people all over America, the supposed dividing line between Bohemian and technician simply no longer exists. People of this sort may have a set of windchimes and a dog with a knotted kerchief 'round its neck, but they're also quite likely to own a multimegabyte Macintosh running MIDI synthesizer software and trippy fractal simulations. These days, even Timothy Leary himself, prophet of LSD, does virtual-reality computer-graphics demos in his lecture tours. John Perry Barlow is not a member of the Grateful Dead. He is, however, a ranking Deadhead. Barlow describes himself as a "techno-crank." A vague term like "social activist" might not be far from the mark, either. But Barlow might be better described as a "poet"--if one keeps in mind Percy Shelley's archaic definition of poets as "unacknowledged legislators of the world." Barlow once made a stab at acknowledged legislator status. In 1987, he narrowly missed the Republican nomination for a seat in the Wyoming State Senate. Barlow is a Wyoming native, the third-generation scion of a well-to-do cattle-ranching family. He is in his early forties, married and the father of three daughters. Barlow is not much troubled by other people's narrow notions of consistency. In the late 1980s, this Republican rock lyricist cattle rancher sold his ranch and became a computer telecommunications devotee. The free-spirited Barlow made this transition with ease. He genuinely enjoyed computers. With a beep of his modem, he leapt from small-town Pinedale, Wyoming, into electronic contact with a large and lively crowd of bright, inventive, technological sophisticates from all over the world. Barlow found the social milieu of computing attractive: its fast-lane pace, its blue-sky rhetoric, its open-endedness. Barlow began dabbling in computer journalism, with marked success, as he was a quick study, and both shrewd and eloquent. He frequently travelled to San Francisco to network with Deadhead friends. There Barlow made extensive contacts throughout the Californian computer community, including friendships among the wilder spirits at Apple. In May 1990, Barlow received a visit from a local Wyoming agent of the FBI. The NuPrometheus case had reached Wyoming. Barlow was troubled to find himself under investigation in an area of his interests once quite free of federal attention. He had to struggle to explain the very nature of computer-crime to a headscratching local FBI man who specialized in cattle-rustling. Barlow, chatting helpfully and demonstrating the wonders of his modem to the puzzled fed, was alarmed to find all "hackers" generally under FBI suspicion as an evil influence in the electronic community. The FBI, in pursuit of a hacker called "NuPrometheus," were tracing attendees of a suspect group called the Hackers Conference. The Hackers Conference, which had been started in 1984, was a yearly Californian meeting of digital pioneers and enthusiasts. The hackers of the Hackers Conference had little if anything to do with the hackers of the digital underground. On the contrary, the hackers of this conference were mostly well-to-do Californian high-tech CEOs, consultants, journalists and entrepreneurs. (This group of hackers were the exact sort of "hackers" most likely to react with militant fury at any criminal degradation of the term "hacker.") Barlow, though he was not arrested or accused of a crime, and though his computer had certainly not gone out the door, was very troubled by this anomaly. He carried the word to the Well. Like the Hackers Conference, "the Well" was an emanation of the Point Foundation. Point Foundation, the inspiration of a wealthy Californian 60s radical named Stewart Brand, was to be a major launch-pad of the civil libertarian effort. Point Foundation's cultural efforts, like those of their fellow Bay Area Californians the Grateful Dead, were multifaceted and multitudinous. Rigid ideological consistency had never been a strong suit of the Whole Earth Catalog. This Point publication had enjoyed a strong vogue during the late 60s and early 70s, when it offered hundreds of practical (and not so practical) tips on communitarian living, environmentalism, and getting back-to-the-land. The Whole Earth Catalog, and its sequels, sold two and half million copies and won a National Book Award. With the slow collapse of American radical dissent, the Whole Earth Catalog had slipped to a more modest corner of the cultural radar; but in its magazine incarnation, CoEvolution Quarterly, the Point Foundation continued to offer a magpie potpourri of "access to tools and ideas." CoEvolution Quarterly, which started in 1974, was never a widely popular magazine. Despite periodic outbreaks of millenarian fervor, CoEvolution Quarterly failed to revolutionize Western civilization and replace leaden centuries of history with bright new Californian paradigms. Instead, this propaganda arm of Point Foundation cakewalked a fine line between impressive brilliance and New Age flakiness. CoEvolution Quarterly carried no advertising, cost a lot, and came out on cheap newsprint with modest black-and-white graphics. It was poorly distributed, and spread mostly by subscription and word of mouth. It could not seem to grow beyond 30,000 subscribers. And yet--it never seemed to shrink much, either. Year in, year out, decade in, decade out, some strange demographic minority accreted to support the magazine. The enthusiastic readership did not seem to have much in the way of coherent politics or ideals. It was sometimes hard to understand what held them together (if the often bitter debate in the letter-columns could be described as "togetherness"). But if the magazine did not flourish, it was resilient; it got by. Then, in 1984, the birth-year of the Macintosh computer, CoEvolution Quarterly suddenly hit the rapids. Point Foundation had discovered the computer revolution. Out came the Whole Earth Software Catalog of 1984, arousing headscratching doubts among the tie-dyed faithful, and rabid enthusiasm among the nascent "cyberpunk" milieu, present company included. Point Foundation started its yearly Hackers Conference, and began to take an extensive interest in the strange new possibilities of digital counterculture. CoEvolution Quarterlyfolded its teepee, replaced by Whole Earth Software Review and eventually by Whole Earth Review (the magazine's present incarnation, currently under the editorship of virtual-reality maven Howard Rheingold). 1985 saw the birth of the "WELL"--the "Whole Earth 'Lectronic Link." The Well was Point Foundation's bulletin board system. As boards went, the Well was an anomaly from the beginning, and remained one. It was local to San Francisco. It was huge, with multiple phonelines and enormous files of commentary. Its complex UNIX-based software might be most charitably described as "user-opaque." It was run on a mainframe out of the rambling offices of a non-profit cultural foundation in Sausalito. And it was crammed with fans of the Grateful Dead. Though the Well was peopled by chattering hipsters of the Bay Area counterculture, it was by no means a "digital underground" board. Teenagers were fairly scarce; most Well users (known as "Wellbeings") were thirty- and forty-something Baby Boomers. They tended to work in the information industry: hardware, software, telecommunications, media, entertainment. Librarians, academics, and journalists were especially common on the Well, attracted by Point Foundation's open-handed distribution of "tools and ideas." There were no anarchy files on the Well, scarcely a dropped hint about access codes or credit-card theft. No one used handles. Vicious "flame-wars" were held to a comparatively civilized rumble. Debates were sometimes sharp, but no Wellbeing ever claimed that a rival had disconnected his phone, trashed his house, or posted his credit card numbers. The Well grew slowly as the 1980s advanced. It charged a modest sum for access and storage, and lost money for years--but not enough to hamper the Point Foundation, which was nonprofit anyway. By 1990, the Well had about five thousand users. These users wandered about a gigantic cyberspace smorgasbord of "Conferences", each conference itself consisting of a welter of "topics," each topic containing dozens, sometimes hundreds of comments, in a tumbling, multiperson debate that could last for months or years on end. In 1991, the Well's list of conferences looked like this: CONFERENCES ON THE WELL WELL "Screenzine" Digest (g zine) Best of the WELL - vintage material - (g best) Index listing of new topics in all conferences - (g newtops) Business - Education ---------------------- Apple Library Users Group(g alug) Agriculture (g agri) Brainstorming (g brain) Classifieds (g cla) Computer Journalism (g cj) Consultants (g consult) Consumers (g cons) Design (g design) Desktop Publishing (g desk) Disability (g disability) Education (g ed) Energy (g energy91) Entrepreneurs (g entre) Homeowners (g home) Indexing (g indexing) Investments (g invest) Kids91 (g kids) Legal (g legal) One Person Business (g one) Periodical/newsletter (g per) Telecomm Law (g tcl) The Future (g fut) Translators (g trans) Travel (g tra) Work (g work) Electronic Frontier Foundation (g eff) Computers, Freedom & Privacy (g cfp) Computer Professionals for Social Responsibility (g cpsr) Social - Political - Humanities --------------------------------- Aging (g gray) AIDS (g aids) Amnesty International (g amnesty) Archives (g arc) Berkeley (g berk) Buddhist (g wonderland) Christian (g cross) Couples (g couples) Current Events (g curr) Dreams (g dream) Drugs (g dru) East Coast (g east) Emotional Health@@@@ (g private) Erotica (g eros) Environment (g env) Firearms (g firearms) First Amendment (g first) Fringes of Reason (g fringes) Gay (g gay) Gay (Private)# (g gaypriv) Geography (g geo) German (g german) Gulf War (g gulf) Hawaii (g aloha) Health (g heal) History (g hist) Holistic (g holi) Interview (g inter) Italian (g ital) Jewish (g jew) Liberty (g liberty) Mind (g mind) Miscellaneous (g misc) Men on the WELL@@ (g mow) Network Integration (g origin) Nonprofits (g non) North Bay (g north) Northwest (g nw) Pacific Rim (g pacrim) Parenting (g par) Peace (g pea) Peninsula (g pen) Poetry (g poetry) Philosophy (g phi) Politics (g pol) Psychology (g psy) Psychotherapy (g therapy) Recovery## (g recovery) San Francisco (g sanfran) Scams (g scam) Sexuality (g sex) Singles (g singles) Southern (g south) Spanish (g spanish) Spirituality (g spirit) Tibet (g tibet) Transportation (g transport) True Confessions (g tru) Unclear (g unclear) WELL Writer's Workshop@@@(g www) Whole Earth (g we) Women on the WELL@(g wow) Words (g words) Writers (g wri) @@@@Private Conference - mail wooly for entry @@@Private conference - mail sonia for entry @@Private conference - mail flash for entry @ Private conference - mail reva for entry # Private Conference - mail hudu for entry ## Private Conference - mail dhawk for entry Arts - Recreation - Entertainment ----------------------------------- ArtCom Electronic Net (g acen) Audio-Videophilia (g aud) Bicycles (g bike) Bay Area Tonight@@(g bat) Boating (g wet) Books (g books) CD's (g cd) Comics (g comics) Cooking (g cook) Flying (g flying) Fun (g fun) Games (g games) Gardening (g gard) Kids (g kids) Nightowls@ (g owl) Jokes (g jokes) MIDI (g midi) Movies (g movies) Motorcycling (g ride) Motoring (g car) Music (g mus) On Stage (g onstage) Pets (g pets) Radio (g rad) Restaurant (g rest) Science Fiction (g sf) Sports (g spo) Star Trek (g trek) Television (g tv) Theater (g theater) Weird (g weird) Zines/Factsheet Five(g f5) @Open from midnight to 6am @@Updated daily Grateful Dead ------------- Grateful Dead (g gd) Deadplan@ (g dp) Deadlit (g deadlit) Feedback (g feedback) GD Hour (g gdh) Tapes (g tapes) Tickets (g tix) Tours (g tours) @Private conference - mail tnf for entry Computers ----------- AI/Forth/Realtime (g realtime) Amiga (g amiga) Apple (g app) Computer Books (g cbook) Art & Graphics (g gra) Hacking (g hack) HyperCard (g hype) IBM PC (g ibm) LANs (g lan) Laptop (g lap) Macintosh (g mac) Mactech (g mactech) Microtimes (g microx) Muchomedia (g mucho) NeXt (g next) OS/2 (g os2) Printers (g print) Programmer's Net (g net) Siggraph (g siggraph) Software Design (g sdc) Software/Programming (g software) Software Support (g ssc) Unix (g unix) Windows (g windows) Word Processing (g word) Technical - Communications ---------------------------- Bioinfo (g bioinfo) Info (g boing) Media (g media) NAPLPS (g naplps) Netweaver (g netweaver) Networld (g networld) Packet Radio (g packet) Photography (g pho) Radio (g rad) Science (g science) Technical Writers (g tec) Telecommunications(g tele) Usenet (g usenet) Video (g vid) Virtual Reality (g vr) The WELL Itself --------------- Deeper (g deeper) Entry (g ent) General (g gentech) Help (g help) Hosts (g hosts) Policy (g policy) System News (g news) Test (g test) The list itself is dazzling, bringing to the untutored eye a dizzying impression of a bizarre milieu of mountain-climbing Hawaiian holistic photographers trading true-life confessions with bisexual word-processing Tibetans. But this confusion is more apparent than real. Each of these conferences was a little cyberspace world in itself, comprising dozens and perhaps hundreds of sub-topics. Each conference was commonly frequented by a fairly small, fairly like-minded community of perhaps a few dozen people. It was humanly impossible to encompass the entire Well (especially since access to the Well's mainframe computer was billed by the hour). Most long-time users contented themselves with a few favorite topical neighborhoods, with the occasional foray elsewhere for a taste of exotica. But especially important news items, and hot topical debates, could catch the attention of the entire Well community. Like any community, the Well had its celebrities, and John Perry Barlow, the silver-tongued and silver-modemed lyricist of the Grateful Dead, ranked prominently among them. It was here on the Well that Barlow posted his true-life tale of computer-crime encounter with the FBI. The story, as might be expected, created a great stir. The Well was already primed for hacker controversy. In December 1989, Harper's magazine had hosted a debate on the Well about the ethics of illicit computer intrusion. While over forty various computer-mavens took part, Barlow proved a star in the debate. So did "Acid Phreak" and "Phiber Optik," a pair of young New York hacker-phreaks whose skills at telco switching-station intrusion were matched only by their apparently limitless hunger for fame. The advent of these two boldly swaggering outlaws in the precincts of the Well created a sensation akin to that of Black Panthers at a cocktail party for the radically chic. Phiber Optik in particular was to seize the day in 1990. A devotee of the 2600 circle and stalwart of the New York hackers' group "Masters of Deception," Phiber Optik was a splendid exemplar of the computer intruder as committed dissident. The eighteen-year-old Optik, a high-school dropout and part-time computer repairman, was young, smart, and ruthlessly obsessive, a sharp-dressing, sharp-talking digital dude who was utterly and airily contemptuous of anyone's rules but his own. By late 1991, Phiber Optik had appeared in Harper's, Esquire, The New York Times, in countless public debates and conventions, even on a television show hosted by Geraldo Rivera. Treated with gingerly respect by Barlow and other Well mavens, Phiber Optik swiftly became a Well celebrity. Strangely, despite his thorny attitude and utter single-mindedness, Phiber Optik seemed to arouse strong protective instincts in most of the people who met him. He was great copy for journalists, always fearlessly ready to swagger, and, better yet, to actually DEMONSTRATE some off-the-wall digital stunt. He was a born media darling. Even cops seemed to recognize that there was something peculiarly unworldly and uncriminal about this particular troublemaker. He was so bold, so flagrant, so young, and so obviously doomed, that even those who strongly disapproved of his actions grew anxious for his welfare, and began to flutter about him as if he were an endangered seal pup. In January 24, 1990 (nine days after the Martin Luther King Day Crash), Phiber Optik, Acid Phreak, and a third NYC scofflaw named Scorpion were raided by the Secret Service. Their computers went out the door, along with the usual blizzard of papers, notebooks, compact disks, answering machines, Sony Walkmans, etc. Both Acid Phreak and Phiber Optik were accused of having caused the Crash. The mills of justice ground slowly. The case eventually fell into the hands of the New York State Police. Phiber had lost his machinery in the raid, but there were no charges filed against him for over a year. His predicament was extensively publicized on the Well, where it caused much resentment for police tactics. It's one thing to merely hear about a hacker raided or busted; it's another to see the police attacking someone you've come to know personally, and who has explained his motives at length. Through the Harper's debate on the Well, it had become clear to the Wellbeings that Phiber Optik was not in fact going to "hurt anything." In their own salad days, many Wellbeings had tasted tear-gas in pitched street-battles with police. They were inclined to indulgence for acts of civil disobedience. Wellbeings were also startled to learn of the draconian thoroughness of a typical hacker search-and-seizure. It took no great stretch of imagination for them to envision themselves suffering much the same treatment. As early as January 1990, sentiment on the Well had already begun to sour, and people had begun to grumble that "hackers" were getting a raw deal from the ham-handed powers-that-be. The resultant issue of Harper's magazine posed the question as to whether computer-intrusion was a "crime" at all. As Barlow put it later: "I've begun to wonder if we wouldn't also regard spelunkers as desperate criminals if AT&T owned all the caves." In February 1991, more than a year after the raid on his home, Phiber Optik was finally arrested, and was charged with first-degree Computer Tampering and Computer Trespass, New York state offenses. He was also charged with a theft-of-service misdemeanor, involving a complex free-call scam to a 900 number. Phiber Optik pled guilty to the misdemeanor charge, and was sentenced to 35 hours of community service. This passing harassment from the unfathomable world of straight people seemed to bother Optik himself little if at all. Deprived of his computer by the January search-and-seizure, he simply bought himself a portable computer so the cops could no longer monitor the phone where he lived with his Mom, and he went right on with his depredations, sometimes on live radio or in front of television cameras. The crackdown raid may have done little to dissuade Phiber Optik, but its galling affect on the Wellbeings was profound. As 1990 rolled on, the slings and arrows mounted: the Knight Lightning raid, the Steve Jackson raid, the nation-spanning Operation Sundevil. The rhetoric of law enforcement made it clear that there was, in fact, a concerted crackdown on hackers in progress. The hackers of the Hackers Conference, the Wellbeings, and their ilk, did not really mind the occasional public misapprehension of "hacking;" if anything, this membrane of differentiation from straight society made the "computer community" feel different, smarter, better. They had never before been confronted, however, by a concerted vilification campaign. Barlow's central role in the counter-struggle was one of the major anomalies of 1990. Journalists investigating the controversy often stumbled over the truth about Barlow, but they commonly dusted themselves off and hurried on as if nothing had happened. It was as if it were TOO MUCH TO BELIEVE that a 1960s freak from the Grateful Dead had taken on a federal law enforcement operation head-to-head and ACTUALLY SEEMED TO BE WINNING! Barlow had no easily detectable power-base for a political struggle of this kind. He had no formal legal or technical credentials. Barlow was, however, a computer networker of truly stellar brilliance. He had a poet's gift of concise, colorful phrasing. He also had a journalist's shrewdness, an off-the-wall, self-deprecating wit, and a phenomenal wealth of simple personal charm. The kind of influence Barlow possessed is fairly common currency in literary, artistic, or musical circles. A gifted critic can wield great artistic influence simply through defining the temper of the times, by coining the catch-phrases and the terms of debate that become the common currency of the period. (And as it happened, Barlow WAS a part-time art critic, with a special fondness for the Western art of Frederic Remington.) Barlow was the first commentator to adopt William Gibson's striking science-fictional term "cyberspace" as a synonym for the present-day nexus of computer and telecommunications networks. Barlow was insistent that cyberspace should be regarded as a qualitatively new world, a "frontier." According to Barlow, the world of electronic communications, now made visible through the computer screen, could no longer be usefully regarded as just a tangle of high-tech wiring. Instead, it had become a PLACE, cyberspace, which demanded a new set of metaphors, a new set of rules and behaviors. The term, as Barlow employed it, struck a useful chord, and this concept of cyberspace was picked up by Time, Scientific American, computer police, hackers, and even Constitutional scholars. "Cyberspace" now seems likely to become a permanent fixture of the language. Barlow was very striking in person: a tall, craggy-faced, bearded, deep-voiced Wyomingan in a dashing Western ensemble of jeans, jacket, cowboy boots, a knotted throat-kerchief and an ever-present Grateful Dead cloisonne lapel pin. Armed with a modem, however, Barlow was truly in his element. Formal hierarchies were not Barlow's strong suit; he rarely missed a chance to belittle the "large organizations and their drones," with their uptight, institutional mindset. Barlow was very much of the free-spirit persuasion, deeply unimpressed by brass-hats and jacks-in-office. But when it came to the digital grapevine, Barlow was a cyberspace ad-hocrat par excellence. There was not a mighty army of Barlows. There was only one Barlow, and he was a fairly anomolous individual. However, the situation only seemed to REQUIRE a single Barlow. In fact, after 1990, many people must have concluded that a single Barlow was far more than they'd ever bargained for. Barlow's querulous mini-essay about his encounter with the FBI struck a strong chord on the Well. A number of other free spirits on the fringes of Apple Computing had come under suspicion, and they liked it not one whit better than he did. One of these was Mitchell Kapor, the co-inventor of the spreadsheet program "Lotus 1-2-3" and the founder of Lotus Development Corporation. Kapor had written-off the passing indignity of being fingerprinted down at his own local Boston FBI headquarters, but Barlow's post made the full national scope of the FBI's dragnet clear to Kapor. The issue now had Kapor's full attention. As the Secret Service swung into anti-hacker operation nationwide in 1990, Kapor watched every move with deep skepticism and growing alarm. As it happened, Kapor had already met Barlow, who had interviewed Kapor for a California computer journal. Like most people who met Barlow, Kapor had been very taken with him. Now Kapor took it upon himself to drop in on Barlow for a heart-to-heart talk about the situation. Kapor was a regular on the Well. Kapor had been a devotee of the Whole Earth Catalogsince the beginning, and treasured a complete run of the magazine. And Kapor not only had a modem, but a private jet. In pursuit of the scattered high-tech investments of Kapor Enterprises Inc., his personal, multi-million dollar holding company, Kapor commonly crossed state lines with about as much thought as one might give to faxing a letter. The Kapor-Barlow council of June 1990, in Pinedale, Wyoming, was the start of the Electronic Frontier Foundation. Barlow swiftly wrote a manifesto, "Crime and Puzzlement," which announced his, and Kapor's, intention to form a political organization to "raise and disburse funds for education, lobbying, and litigation in the areas relating to digital speech and the extension of the Constitution into Cyberspace." Furthermore, proclaimed the manifesto, the foundation would "fund, conduct, and support legal efforts to demonstrate that the Secret Service has exercised prior restraint on publications, limited free speech, conducted improper seizure of equipment and data, used undue force, and generally conducted itself in a fashion which is arbitrary, oppressive, and unconstitutional." "Crime and Puzzlement" was distributed far and wide through computer networking channels, and also printed in the Whole Earth Review. The sudden declaration of a coherent, politicized counter-strike from the ranks of hackerdom electrified the community. Steve Wozniak (perhaps a bit stung by the NuPrometheus scandal) swiftly offered to match any funds Kapor offered the Foundation. John Gilmore, one of the pioneers of Sun Microsystems, immediately offered his own extensive financial and personal support. Gilmore, an ardent libertarian, was to prove an eloquent advocate of electronic privacy issues, especially freedom from governmental and corporate computer-assisted surveillance of private citizens. A second meeting in San Francisco rounded up further allies: Stewart Brand of the Point Foundation, virtual-reality pioneers Jaron Lanier and Chuck Blanchard, network entrepreneur and venture capitalist Nat Goldhaber. At this dinner meeting, the activists settled on a formal title: the Electronic Frontier Foundation, Incorporated. Kapor became its president. A new EFF Conference was opened on the Point Foundation's Well, and the Well was declared "the home of the Electronic Frontier Foundation." Press coverage was immediate and intense. Like their nineteenth-century spiritual ancestors, Alexander Graham Bell and Thomas Watson, the high-tech computer entrepreneurs of the 1970s and 1980s--people such as Wozniak, Jobs, Kapor, Gates, and H. Ross Perot, who had raised themselves by their bootstraps to dominate a glittering new industry--had always made very good copy. But while the Wellbeings rejoiced, the press in general seemed nonplussed by the self-declared "civilizers of cyberspace." EFF's insistence that the war against "hackers" involved grave Constitutional civil liberties issues seemed somewhat farfetched, especially since none of EFF's organizers were lawyers or established politicians. The business press in particular found it easier to seize on the apparent core of the story-- that high-tech entrepreneur Mitchell Kapor had established a "defense fund for hackers." Was EFF a genuinely important political development--or merely a clique of wealthy eccentrics, dabbling in matters better left to the proper authorities? The jury was still out. But the stage was now set for open confrontation. And the first and the most critical battle was the hacker show-trial of "Knight Lightning." # It has been my practice throughout this book to refer to hackers only by their "handles." There is little to gain by giving the real names of these people, many of whom are juveniles, many of whom have never been convicted of any crime, and many of whom had unsuspecting parents who have already suffered enough. But the trial of Knight Lightning on July 24-27, 1990, made this particular "hacker" a nationally known public figure. It can do no particular harm to himself or his family if I repeat the long-established fact that his name is Craig Neidorf (pronounced NYE-dorf). Neidorf's jury trial took place in the United States District Court, Northern District of Illinois, Eastern Division, with the Honorable Nicholas J. Bua presiding. The United States of America was the plaintiff, the defendant Mr. Neidorf. The defendant's attorney was Sheldon T. Zenner of the Chicago firm of Katten, Muchin and Zavis. The prosecution was led by the stalwarts of the Chicago Computer Fraud and Abuse Task Force: William J. Cook, Colleen D. Coughlin, and David A. Glockner, all Assistant United States Attorneys. The Secret Service Case Agent was Timothy M. Foley. It will be recalled that Neidorf was the co-editor of an underground hacker "magazine" called Phrack. Phrack was an entirely electronic publication, distributed through bulletin boards and over electronic networks. It was amateur publication given away for free. Neidorf had never made any money for his work in Phrack. Neither had his unindicted co-editor "Taran King" or any of the numerous Phrack contributors. The Chicago Computer Fraud and Abuse Task Force, however, had decided to prosecute Neidorf as a fraudster. To formally admit that Phrack was a "magazine" and Neidorf a "publisher" was to open a prosecutorial Pandora's Box of First Amendment issues. To do this was to play into the hands of Zenner and his EFF advisers, which now included a phalanx of prominent New York civil rights lawyers as well as the formidable legal staff of Katten, Muchin and Zavis. Instead, the prosecution relied heavily on the issue of access device fraud: Section 1029 of Title 18, the section from which the Secret Service drew its most direct jurisdiction over computer crime. Neidorf's alleged crimes centered around the E911 Document. He was accused of having entered into a fraudulent scheme with the Prophet, who, it will be recalled, was the Atlanta LoD member who had illicitly copied the E911 Document from the BellSouth AIMSX system. The Prophet himself was also a co-defendant in the Neidorf case, part-and-parcel of the alleged "fraud scheme" to "steal" BellSouth's E911 Document (and to pass the Document across state lines, which helped establish the Neidorf trial as a federal case). The Prophet, in the spirit of full co-operation, had agreed to testify against Neidorf. In fact, all three of the Atlanta crew stood ready to testify against Neidorf. Their own federal prosecutors in Atlanta had charged the Atlanta Three with: (a) conspiracy, (b) computer fraud, (c) wire fraud, (d) access device fraud, and (e) interstate transportation of stolen property (Title 18, Sections 371, 1030, 1343, 1029, and 2314). Faced with this blizzard of trouble, Prophet and Leftist had ducked any public trial and had pled guilty to reduced charges--one conspiracy count apiece. Urvile had pled guilty to that odd bit of Section 1029 which makes it illegal to possess "fifteen or more" illegal access devices (in his case, computer passwords). And their sentences were scheduled for September 14, 1990--well after the Neidorf trial. As witnesses, they could presumably be relied upon to behave. Neidorf, however, was pleading innocent. Most everyone else caught up in the crackdown had "cooperated fully" and pled guilty in hope of reduced sentences. (Steve Jackson was a notable exception, of course, and had strongly protested his innocence from the very beginning. But Steve Jackson could not get a day in court-- Steve Jackson had never been charged with any crime in the first place.) Neidorf had been urged to plead guilty. But Neidorf was a political science major and was disinclined to go to jail for "fraud" when he had not made any money, had not broken into any computer, and had been publishing a magazine that he considered protected under the First Amendment. Neidorf's trial was the ONLY legal action of the entire Crackdown that actually involved bringing the issues at hand out for a public test in front of a jury of American citizens. Neidorf, too, had cooperated with investigators. He had voluntarily handed over much of the evidence that had led to his own indictment. He had already admitted in writing that he knew that the E911 Document had been stolen before he had "published" it in Phrack--or, from the prosecution's point of view, illegally transported stolen property by wire in something purporting to be a "publication." But even if the "publication" of the E911 Document was not held to be a crime, that wouldn't let Neidorf off the hook. Neidorf had still received the E911 Document when Prophet had transferred it to him from Rich Andrews' Jolnet node. On that occasion, it certainly hadn't been "published"-- it was hacker booty, pure and simple, transported across state lines. The Chicago Task Force led a Chicago grand jury to indict Neidorf on a set of charges that could have put him in jail for thirty years. When some of these charges were successfully challenged before Neidorf actually went to trial, the Chicago Task Force rearranged his indictment so that he faced a possible jail term of over sixty years! As a first offender, it was very unlikely that Neidorf would in fact receive a sentence so drastic; but the Chicago Task Force clearly intended to see Neidorf put in prison, and his conspiratorial "magazine" put permanently out of commission. This was a federal case, and Neidorf was charged with the fraudulent theft of property worth almost eighty thousand dollars. William Cook was a strong believer in high-profile prosecutions with symbolic overtones. He often published articles on his work in the security trade press, arguing that "a clear message had to be sent to the public at large and the computer community in particular that unauthorized attacks on computers and the theft of computerized information would not be tolerated by the courts." The issues were complex, the prosecution's tactics somewhat unorthodox, but the Chicago Task Force had proved sure-footed to date. "Shadowhawk" had been bagged on the wing in 1989 by the Task Force, and sentenced to nine months in prison, and a $10,000 fine. The Shadowhawk case involved charges under Section 1030, the "federal interest computer" section. Shadowhawk had not in fact been a devotee of "federal-interest" computers per se. On the contrary, Shadowhawk, who owned an AT&T home computer, seemed to cherish a special aggression toward AT&T. He had bragged on the underground boards "Phreak Klass 2600" and "Dr. Ripco" of his skills at raiding AT&T, and of his intention to crash AT&T's national phone system. Shadowhawk's brags were noticed by Henry Kluepfel of Bellcore Security, scourge of the outlaw boards, whose relations with the Chicago Task Force were long and intimate. The Task Force successfully established that Section 1030 applied to the teenage Shadowhawk, despite the objections of his defense attorney. Shadowhawk had entered a computer "owned" by U.S. Missile Command and merely "managed" by AT&T. He had also entered an AT&T computer located at Robbins Air Force Base in Georgia. Attacking AT&T was of "federal interest" whether Shadowhawk had intended it or not. The Task Force also convinced the court that a piece of AT&T software that Shadowhawk had illicitly copied from Bell Labs, the "Artificial Intelligence C5 Expert System," was worth a cool one million dollars. Shadowhawk's attorney had argued that Shadowhawk had not sold the program and had made no profit from the illicit copying. And in point of fact, the C5 Expert System was experimental software, and had no established market value because it had never been on the market in the first place. AT&T's own assessment of a "one million dollar" figure for its own intangible property was accepted without challenge by the court, however. And the court concurred with the government prosecutors that Shadowhawk showed clear "intent to defraud" whether he'd gotten any money or not. Shadowhawk went to jail. The Task Force's other best-known triumph had been the conviction and jailing of "Kyrie." Kyrie, a true denizen of the digital criminal underground, was a 36-year-old Canadian woman, convicted and jailed for telecommunications fraud in Canada. After her release from prison, she had fled the wrath of Canada Bell and the Royal Canadian Mounted Police, and eventually settled, very unwisely, in Chicago. "Kyrie," who also called herself "Long Distance Information," specialized in voice-mail abuse. She assembled large numbers of hot long-distance codes, then read them aloud into a series of corporate voice-mail systems. Kyrie and her friends were electronic squatters in corporate voice-mail systems, using them much as if they were pirate bulletin boards, then moving on when their vocal chatter clogged the system and the owners necessarily wised up. Kyrie's camp followers were a loose tribe of some hundred and fifty phone-phreaks, who followed her trail of piracy from machine to machine, ardently begging for her services and expertise. Kyrie's disciples passed her stolen credit-card numbers, in exchange for her stolen "long distance information." Some of Kyrie's clients paid her off in cash, by scamming credit-card cash advances from Western Union. Kyrie travelled incessantly, mostly through airline tickets and hotel rooms that she scammed through stolen credit cards. Tiring of this, she found refuge with a fellow female phone phreak in Chicago. Kyrie's hostess, like a surprising number of phone phreaks, was blind. She was also physically disabled. Kyrie allegedly made the best of her new situation by applying for, and receiving, state welfare funds under a false identity as a qualified caretaker for the handicapped. Sadly, Kyrie's two children by a former marriage had also vanished underground with her; these pre-teen digital refugees had no legal American identity, and had never spent a day in school. Kyrie was addicted to technical mastery and enthralled by her own cleverness and the ardent worship of her teenage followers. This foolishly led her to phone up Gail Thackeray in Arizona, to boast, brag, strut, and offer to play informant. Thackeray, however, had already learned far more than enough about Kyrie, whom she roundly despised as an adult criminal corrupting minors, a "female Fagin." Thackeray passed her tapes of Kyrie's boasts to the Secret Service. Kyrie was raided and arrested in Chicago in May 1989. She confessed at great length and pled guilty. In August 1990, Cook and his Task Force colleague Colleen Coughlin sent Kyrie to jail for 27 months, for computer and telecommunications fraud. This was a markedly severe sentence by the usual wrist-slapping standards of "hacker" busts. Seven of Kyrie's foremost teenage disciples were also indicted and convicted. The Kyrie "high-tech street gang," as Cook described it, had been crushed. Cook and his colleagues had been the first ever to put someone in prison for voice-mail abuse. Their pioneering efforts had won them attention and kudos. In his article on Kyrie, Cook drove the message home to the readers of Security Management magazine, a trade journal for corporate security professionals. The case, Cook said, and Kyrie's stiff sentence, "reflect a new reality for hackers and computer crime victims in the '90s. . . . Individuals and corporations who report computer and telecommunications crimes can now expect that their cooperation with federal law enforcement will result in meaningful punishment. Companies and the public at large must report computer-enhanced crimes if they want prosecutors and the course to protect their rights to the tangible and intangible property developed and stored on computers." Cook had made it his business to construct this "new reality for hackers." He'd also made it his business to police corporate property rights to the intangible. Had the Electronic Frontier Foundation been a "hacker defense fund" as that term was generally understood, they presumably would have stood up for Kyrie. Her 1990 sentence did indeed send a "message" that federal heat was coming down on "hackers." But Kyrie found no defenders at EFF, or anywhere else, for that matter. EFF was not a bail-out fund for electronic crooks. The Neidorf case paralleled the Shadowhawk case in certain ways. The victim once again was allowed to set the value of the "stolen" property. Once again Kluepfel was both investigator and technical advisor. Once again no money had changed hands, but the "intent to defraud" was central. The prosecution's case showed signs of weakness early on. The Task Force had originally hoped to prove Neidorf the center of a nationwide Legion of Doom criminal conspiracy. The Phrack editors threw physical get-togethers every summer, which attracted hackers from across the country; generally two dozen or so of the magazine's favorite contributors and readers. (Such conventions were common in the hacker community; 2600 Magazine, for instance, held public meetings of hackers in New York, every month.) LoD heavy-dudes were always a strong presence at these Phrack-sponsored "Summercons." In July 1988, an Arizona hacker named "Dictator" attended Summercon in Neidorf's home town of St. Louis. Dictator was one of Gail Thackeray's underground informants; Dictator's underground board in Phoenix was a sting operation for the Secret Service. Dictator brought an undercover crew of Secret Service agents to Summercon. The agents bored spyholes through the wall of Dictator's hotel room in St Louis, and videotaped the frolicking hackers through a one-way mirror. As it happened, however, nothing illegal had occurred on videotape, other than the guzzling of beer by a couple of minors. Summercons were social events, not sinister cabals. The tapes showed fifteen hours of raucous laughter, pizza-gobbling, in-jokes and back-slapping. Neidorf's lawyer, Sheldon Zenner, saw the Secret Service tapes before the trial. Zenner was shocked by the complete harmlessness of this meeting, which Cook had earlier characterized as a sinister interstate conspiracy to commit fraud. Zenner wanted to show the Summercon tapes to the jury. It took protracted maneuverings by the Task Force to keep the tapes from the jury as "irrelevant." The E911 Document was also proving a weak reed. It had originally been valued at $79,449. Unlike Shadowhawk's arcane Artificial Intelligence booty, the E911 Document was not software--it was written in English. Computer-knowledgeable people found this value--for a twelve-page bureaucratic document--frankly incredible. In his "Crime and Puzzlement" manifesto for EFF, Barlow commented: "We will probably never know how this figure was reached or by whom, though I like to imagine an appraisal team consisting of Franz Kafka, Joseph Heller, and Thomas Pynchon." As it happened, Barlow was unduly pessimistic. The EFF did, in fact, eventually discover exactly how this figure was reached, and by whom-- but only in 1991, long after the Neidorf trial was over. Kim Megahee, a Southern Bell security manager, had arrived at the document's value by simply adding up the "costs associated with the production" of the E911 Document. Those "costs" were as follows: 1. A technical writer had been hired to research and write the E911 Document. 200 hours of work, at $35 an hour, cost : $7,000. A Project Manager had overseen the technical writer. 200 hours, at $31 an hour, made: $6,200. 2. A week of typing had cost $721 dollars. A week of formatting had cost $721. A week of graphics formatting had cost $742. 3. Two days of editing cost $367. 4. A box of order labels cost five dollars. 5. Preparing a purchase order for the Document, including typing and the obtaining of an authorizing signature from within the BellSouth bureaucracy, cost $129. 6. Printing cost $313. Mailing the Document to fifty people took fifty hours by a clerk, and cost $858. 7. Placing the Document in an index took two clerks an hour each, totalling $43. Bureaucratic overhead alone, therefore, was alleged to have cost a whopping $17,099. According to Mr. Megahee, the typing of a twelve-page document had taken a full week. Writing it had taken five weeks, including an overseer who apparently did nothing else but watch the author for five weeks. Editing twelve pages had taken two days. Printing and mailing an electronic document (which was already available on the Southern Bell Data Network to any telco employee who needed it), had cost over a thousand dollars. But this was just the beginning. There were also the HARDWARE EXPENSES. Eight hundred fifty dollars for a VT220 computer monitor. THIRTY-ONE THOUSAND DOLLARS for a sophisticated VAXstation II computer. Six thousand dollars for a computer printer. TWENTY-TWO THOUSAND DOLLARS for a copy of "Interleaf" software. Two thousand five hundred dollars for VMS software. All this to create the twelve-page Document. Plus ten percent of the cost of the software and the hardware, for maintenance. (Actually, the ten percent maintenance costs, though mentioned, had been left off the final $79,449 total, apparently through a merciful oversight). Mr. Megahee's letter had been mailed directly to William Cook himself, at the office of the Chicago federal attorneys. The United States Government accepted these telco figures without question. As incredulity mounted, the value of the E911 Document was officially revised downward. This time, Robert Kibler of BellSouth Security estimated the value of the twelve pages as a mere $24,639.05--based, purportedly, on "R&D costs." But this specific estimate, right down to the nickel, did not move the skeptics at all; in fact it provoked open scorn and a torrent of sarcasm. The financial issues concerning theft of proprietary information have always been peculiar. It could be argued that BellSouth had not "lost" its E911 Document at all in the first place, and therefore had not suffered any monetary damage from this "theft." And Sheldon Zenner did in fact argue this at Neidorf's trial-- that Prophet's raid had not been "theft," but was better understood as illicit copying. The money, however, was not central to anyone's true purposes in this trial. It was not Cook's strategy to convince the jury that the E911 Document was a major act of theft and should be punished for that reason alone. His strategy was to argue that the E911 Document was DANGEROUS. It was his intention to establish that the E911 Document was "a road-map" to the Enhanced 911 System. Neidorf had deliberately and recklessly distributed a dangerous weapon. Neidorf and the Prophet did not care (or perhaps even gloated at the sinister idea) that the E911 Document could be used by hackers to disrupt 911 service, "a life line for every person certainly in the Southern Bell region of the United States, and indeed, in many communities throughout the United States," in Cook's own words. Neidorf had put people's lives in danger. In pre-trial maneuverings, Cook had established that the E911 Document was too hot to appear in the public proceedings of the Neidorf trial. The JURY ITSELF would not be allowed to ever see this Document, lest it slip into the official court records, and thus into the hands of the general public, and, thus, somehow, to malicious hackers who might lethally abuse it. Hiding the E911 Document from the jury may have been a clever legal maneuver, but it had a severe flaw. There were, in point of fact, hundreds, perhaps thousands, of people, already in possession of the E911 Document, just as Phrack had published it. Its true nature was already obvious to a wide section of the interested public (all of whom, by the way, were, at least theoretically, party to a gigantic wire-fraud conspiracy). Most everyone in the electronic community who had a modem and any interest in the Neidorf case already had a copy of the Document. It had already been available in Phrack for over a year. People, even quite normal people without any particular prurient interest in forbidden knowledge, did not shut their eyes in terror at the thought of beholding a "dangerous" document from a telephone company. On the contrary, they tended to trust their own judgement and simply read the Document for themselves. And they were not impressed. One such person was John Nagle. Nagle was a forty-one-year-old professional programmer with a masters' degree in computer science from Stanford. He had worked for Ford Aerospace, where he had invented a computer-networking technique known as the "Nagle Algorithm," and for the prominent Californian computer-graphics firm "Autodesk," where he was a major stockholder. Nagle was also a prominent figure on the Well, much respected for his technical knowledgeability. Nagle had followed the civil-liberties debate closely, for he was an ardent telecommunicator. He was no particular friend of computer intruders, but he believed electronic publishing had a great deal to offer society at large, and attempts to restrain its growth, or to censor free electronic expression, strongly roused his ire. The Neidorf case, and the E911 Document, were both being discussed in detail on the Internet, in an electronic publication called Telecom Digest. Nagle, a longtime Internet maven, was a regular reader of Telecom Digest. Nagle had never seen a copy of Phrack, but the implications of the case disturbed him. While in a Stanford bookstore hunting books on robotics, Nagle happened across a book called The Intelligent Network. Thumbing through it at random, Nagle came across an entire chapter meticulously detailing the workings of E911 police emergency systems. This extensive text was being sold openly, and yet in Illinois a young man was in danger of going to prison for publishing a thin six-page document about 911 service. Nagle made an ironic comment to this effect in Telecom Digest. From there, Nagle was put in touch with Mitch Kapor, and then with Neidorf's lawyers. Sheldon Zenner was delighted to find a computer telecommunications expert willing to speak up for Neidorf, one who was not a wacky teenage "hacker." Nagle was fluent, mature, and respectable; he'd once had a federal security clearance. Nagle was asked to fly to Illinois to join the defense team. Having joined the defense as an expert witness, Nagle read the entire E911 Document for himself. He made his own judgement about its potential for menace. The time has now come for you yourself, the reader, to have a look at the E911 Document. This six-page piece of work was the pretext for a federal prosecution that could have sent an electronic publisher to prison for thirty, or even sixty, years. It was the pretext for the search and seizure of Steve Jackson Games, a legitimate publisher of printed books. It was also the formal pretext for the search and seizure of the Mentor's bulletin board, "Phoenix Project," and for the raid on the home of Erik Bloodaxe. It also had much to do with the seizure of Richard Andrews' Jolnet node and the shutdown of Charles Boykin's AT&T node. The E911 Document was the single most important piece of evidence in the Hacker Crackdown. There can be no real and legitimate substitute for the Document itself. ==Phrack Inc.== Volume Two, Issue 24, File 5 of 13 Control Office Administration Of Enhanced 911 Services For Special Services and Account Centers by the Eavesdropper March, 1988 Description of Service ~~~~~~~~~~~~~~~~~~~~~ The control office for Emergency 911 service is assigned in accordance with the existing standard guidelines to one of the following centers: o Special Services Center (SSC) o Major Accounts Center (MAC) o Serving Test Center (STC) o Toll Control Center (TCC) The SSC/MAC designation is used in this document interchangeably for any of these four centers. The Special Services Centers (SSCs) or Major Account Centers (MACs) have been designated as the trouble reporting contact for all E911 customer (PSAP) reported troubles. Subscribers who have trouble on an E911 call will continue to contact local repair service (CRSAB) who will refer the trouble to the SSC/MAC, when appropriate. Due to the critical nature of E911 service, the control and timely repair of troubles is demanded. As the primary E911 customer contact, the SSC/MAC is in the unique position to monitor the status of the trouble and insure its resolution. System Overview ~~~~~~~~~~~~~~ The number 911 is intended as a nationwide universal telephone number which provides the public with direct access to a Public Safety Answering Point (PSAP). A PSAP is also referred to as an Emergency Service Bureau (ESB). A PSAP is an agency or facility which is authorized by a municipality to receive and respond to police, fire and/or ambulance services. One or more attendants are located at the PSAP facilities to receive and handle calls of an emergency nature in accordance with the local municipal requirements. An important advantage of E911 emergency service is improved (reduced) response times for emergency services. Also close coordination among agencies providing various emergency services is a valuable capability provided by E911 service. 1A ESS is used as the tandem office for the E911 network to route all 911 calls to the correct (primary) PSAP designated to serve the calling station. The E911 feature was developed primarily to provide routing to the correct PSAP for all 911 calls. Selective routing allows a 911 call originated from a particular station located in a particular district, zone, or town, to be routed to the primary PSAP designated to serve that customer station regardless of wire center boundaries. Thus, selective routing eliminates the problem of wire center boundaries not coinciding with district or other political boundaries. The services available with the E911 feature include: Forced Disconnect Default Routing Alternative Routing Night Service Selective Routing Automatic Number Identification (ANI) Selective Transfer Automatic Location Identification (ALI) Preservice/Installation Guidelines ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ When a contract for an E911 system has been signed, it is the responsibility of Network Marketing to establish an implementation/cutover committee which should include a representative from the SSC/MAC. Duties of the E911 Implementation Team include coordination of all phases of the E911 system deployment and the formation of an on-going E911 maintenance subcommittee. Marketing is responsible for providing the following customer specific information to the SSC/MAC prior to the start of call through testing: o All PSAP's (name, address, local contact) o All PSAP circuit ID's o 1004 911 service request including PSAP details on each PSAP (1004 Section K, L, M) o Network configuration o Any vendor information (name, telephone number, equipment) The SSC/MAC needs to know if the equipment and sets at the PSAP are maintained by the BOCs, an independent company, or an outside vendor, or any combination. This information is then entered on the PSAP profile sheets and reviewed quarterly for changes, additions and deletions. Marketing will secure the Major Account Number (MAN) and provide this number to Corporate Communications so that the initial issue of the service orders carry the MAN and can be tracked by the SSC/MAC via CORDNET. PSAP circuits are official services by definition. All service orders required for the installation of the E911 system should include the MAN assigned to the city/county which has purchased the system. In accordance with the basic SSC/MAC strategy for provisioning, the SSC/MAC will be Overall Control Office (OCO) for all Node to PSAP circuits (official services) and any other services for this customer. Training must be scheduled for all SSC/MAC involved personnel during the pre-service stage of the project. The E911 Implementation Team will form the on-going maintenance subcommittee prior to the initial implementation of the E911 system. This sub-committee will establish post implementation quality assurance procedures to ensure that the E911 system continues to provide quality service to the customer. Customer/Company training, trouble reporting interfaces for the customer, telephone company and any involved independent telephone companies needs to be addressed and implemented prior to E911 cutover. These functions can be best addressed by the formation of a sub- committee of the E911 Implementation Team to set up guidelines for and to secure service commitments of interfacing organizations. A SSC/MAC supervisor should chair this subcommittee and include the following organizations: 1) Switching Control Center - E911 translations - Trunking - End office and Tandem office hardware/software 2) Recent Change Memory Administration Center - Daily RC update activity for TN/ESN translations - Processes validity errors and rejects 3) Line and Number Administration - Verification of TN/ESN translations 4) Special Service Center/Major Account Center - Single point of contact for all PSAP and Node to host troubles - Logs, tracks & statusing of all trouble reports - Trouble referral, follow up, and escalation - Customer notification of status and restoration - Analyzation of "chronic" troubles - Testing, installation and maintenance of E911 circuits 5) Installation and Maintenance (SSIM/I&M) - Repair and maintenance of PSAP equipment and Telco owned sets 6) Minicomputer Maintenance Operations Center - E911 circuit maintenance (where applicable) 7) Area Maintenance Engineer - Technical assistance on voice (CO-PSAP) network related E911 troubles Maintenance Guidelines ~~~~~~~~~~~~~~~~~~~~~ The CCNC will test the Node circuit from the 202T at the Host site to the 202T at the Node site. Since Host to Node (CCNC to MMOC) circuits are official company services, the CCNC will refer all Node circuit troubles to the SSC/MAC. The SSC/MAC is responsible for the testing and follow up to restoration of these circuit troubles. Although Node to PSAP circuit are official services, the MMOC will refer PSAP circuit troubles to the appropriate SSC/MAC. The SSC/MAC is responsible for testing and follow up to restoration of PSAP circuit troubles. The SSC/MAC will also receive reports from CRSAB/IMC(s) on subscriber 911 troubles when they are not line troubles. The SSC/MAC is responsible for testing and restoration of these troubles. Maintenance responsibilities are as follows: SCC@ Voice Network (ANI to PSAP) @SCC responsible for tandem switch SSIM/I&M PSAP Equipment (Modems, CIU's, sets) Vendor PSAP Equipment (when CPE) SSC/MAC PSAP to Node circuits, and tandem to PSAP voice circuits (EMNT) MMOC Node site (Modems, cables, etc) Note: All above work groups are required to resolve troubles by interfacing with appropriate work groups for resolution. The Switching Control Center (SCC) is responsible for E911/1AESS translations in tandem central offices. These translations route E911 calls, selective transfer, default routing, speed calling, etc., for each PSAP. The SCC is also responsible for troubleshooting on the voice network (call originating to end office tandem equipment). For example, ANI failures in the originating offices would be a responsibility of the SCC. Recent Change Memory Administration Center (RCMAC) performs the daily tandem translation updates (recent change) for routing of individual telephone numbers. Recent changes are generated from service order activity (new service, address changes, etc.) and compiled into a daily file by the E911 Center (ALI/DMS E911 Computer). SSIM/I&M is responsible for the installation and repair of PSAP equipment. PSAP equipment includes ANI Controller, ALI Controller, data sets, cables, sets, and other peripheral equipment that is not vendor owned. SSIM/I&M is responsible for establishing maintenance test kits, complete with spare parts for PSAP maintenance. This includes test gear, data sets, and ANI/ALI Controller parts. Special Services Center (SSC) or Major Account Center (MAC) serves as the trouble reporting contact for all (PSAP) troubles reported by customer. The SSC/MAC refers troubles to proper organizations for handling and tracks status of troubles, escalating when necessary. The SSC/MAC will close out troubles with customer. The SSC/MAC will analyze all troubles and tracks "chronic" PSAP troubles. Corporate Communications Network Center (CCNC) will test and refer troubles on all node to host circuits. All E911 circuits are classified as official company property. The Minicomputer Maintenance Operations Center (MMOC) maintains the E911 (ALI/DMS) computer hardware at the Host site. This MMOC is also responsible for monitoring the system and reporting certain PSAP and system problems to the local MMOC's, SCC's or SSC/MAC's. The MMOC personnel also operate software programs that maintain the TN data base under the direction of the E911 Center. The maintenance of the NODE computer (the interface between the PSAP and the ALI/DMS computer) is a function of the MMOC at the NODE site. The MMOC's at the NODE sites may also be involved in the testing of NODE to Host circuits. The MMOC will also assist on Host to PSAP and data network related troubles not resolved through standard trouble clearing procedures. Installation And Maintenance Center (IMC) is responsible for referral of E911 subscriber troubles that are not subscriber line problems. E911 Center - Performs the role of System Administration and is responsible for overall operation of the E911 computer software. The E911 Center does A-Z trouble analysis and provides statistical information on the performance of the system. This analysis includes processing PSAP inquiries (trouble reports) and referral of network troubles. The E911 Center also performs daily processing of tandem recent change and provides information to the RCMAC for tandem input. The E911 Center is responsible for daily processing of the ALI/DMS computer data base and provides error files, etc. to the Customer Services department for investigation and correction. The E911 Center participates in all system implementations and on-going maintenance effort and assists in the development of procedures, training and education of information to all groups. Any group receiving a 911 trouble from the SSC/MAC should close out the trouble with the SSC/MAC or provide a status if the trouble has been referred to another group. This will allow the SSC/MAC to provide a status back to the customer or escalate as appropriate. Any group receiving a trouble from the Host site (MMOC or CCNC) should close the trouble back to that group. The MMOC should notify the appropriate SSC/MAC when the Host, Node, or all Node circuits are down so that the SSC/MAC can reply to customer reports that may be called in by the PSAPs. This will eliminate duplicate reporting of troubles. On complete outages the MMOC will follow escalation procedures for a Node after two (2) hours and for a PSAP after four (4) hours. Additionally the MMOC will notify the appropriate SSC/MAC when the Host, Node, or all Node circuits are down. The PSAP will call the SSC/MAC to report E911 troubles. The person reporting the E911 trouble may not have a circuit I.D. and will therefore report the PSAP name and address. Many PSAP troubles are not circuit specific. In those instances where the caller cannot provide a circuit I.D., the SSC/MAC will be required to determine the circuit I.D. using the PSAP profile. Under no circumstances will the SSC/MAC Center refuse to take the trouble. The E911 trouble should be handled as quickly as possible, with the SSC/MAC providing as much assistance as possible while taking the trouble report from the caller. The SSC/MAC will screen/test the trouble to determine the appropriate handoff organization based on the following criteria: PSAP equipment problem: SSIM/I&M Circuit problem: SSC/MAC Voice network problem: SCC (report trunk group number) Problem affecting multiple PSAPs (No ALI report from all PSAPs): Contact the MMOC to check for NODE or Host computer problems before further testing. The SSC/MAC will track the status of reported troubles and escalate as appropriate. The SSC/MAC will close out customer/company reports with the initiating contact. Groups with specific maintenance responsibilities, defined above, will investigate "chronic" troubles upon request from the SSC/MAC and the ongoing maintenance subcommittee. All "out of service" E911 troubles are priority one type reports. One link down to a PSAP is considered a priority one trouble and should be handled as if the PSAP was isolated. The PSAP will report troubles with the ANI controller, ALI controller or set equipment to the SSC/MAC. NO ANI: Where the PSAP reports NO ANI (digital display screen is blank) ask if this condition exists on all screens and on all calls. It is important to differentiate between blank screens and screens displaying 911-00XX, or all zeroes. When the PSAP reports all screens on all calls, ask if there is any voice contact with callers. If there is no voice contact the trouble should be referred to the SCC immediately since 911 calls are not getting through which may require alternate routing of calls to another PSAP. When the PSAP reports this condition on all screens but not all calls and has voice contact with callers, the report should be referred to SSIM/I&M for dispatch. The SSC/MAC should verify with the SCC that ANI is pulsing before dispatching SSIM. When the PSAP reports this condition on one screen for all calls (others work fine) the trouble should be referred to SSIM/I&M for dispatch, because the trouble is isolated to one piece of equipment at the customer premise. An ANI failure (i.e. all zeroes) indicates that the ANI has not been received by the PSAP from the tandem office or was lost by the PSAP ANI controller. The PSAP may receive "02" alarms which can be caused by the ANI controller logging more than three all zero failures on the same trunk. The PSAP has been instructed to report this condition to the SSC/MAC since it could indicate an equipment trouble at the PSAP which might be affecting all subscribers calling into the PSAP. When all zeroes are being received on all calls or "02" alarms continue, a tester should analyze the condition to determine the appropriate action to be taken. The tester must perform cooperative testing with the SCC when there appears to be a problem on the Tandem-PSAP trunks before requesting dispatch. When an occasional all zero condition is reported, the SSC/MAC should dispatch SSIM/I&M to routine equipment on a "chronic" troublesweep. The PSAPs are instructed to report incidental ANI failures to the BOC on a PSAP inquiry trouble ticket (paper) that is sent to the Customer Services E911 group and forwarded to E911 center when required. This usually involves only a particular telephone number and is not a condition that would require a report to the SSC/MAC. Multiple ANI failures which our from the same end office (XX denotes end office), indicate a hard trouble condition may exist in the end office or end office tandem trunks. The PSAP will report this type of condition to the SSC/MAC and the SSC/MAC should refer the report to the SCC responsible for the tandem office. NOTE: XX is the ESCO (Emergency Service Number) associated with the incoming 911 trunks into the tandem. It is important that the C/MAC tell the SCC what is displayed at the PSAP (i.e. 911-0011) which indicates to the SCC which end office is in trouble. Note: It is essential that the PSAP fill out inquiry form on every ANI failure. The PSAP will report a trouble any time an address is not received on an address display (screen blank) E911 call. (If a record is not in the 911 data base or an ANI failure is encountered, the screen will provide a display noticing such condition). The SSC/MAC should verify with the PSAP whether the NO ALI condition is on one screen or all screens. When the condition is on one screen (other screens receive ALI information) the SSC/MAC will request SSIM/I&M to dispatch. If no screens are receiving ALI information, there is usually a circuit trouble between the PSAP and the Host computer. The SSC/MAC should test the trouble and refer for restoral. Note: If the SSC/MAC receives calls from multiple PSAP's, all of which are receiving NO ALI, there is a problem with the Node or Node to Host circuits or the Host computer itself. Before referring the trouble the SSC/MAC should call the MMOC to inquire if the Node or Host is in trouble. Alarm conditions on the ANI controller digital display at the PSAP are to be reported by the PSAP's. These alarms can indicate various trouble conditions so the SSC/MAC should ask the PSAP if any portion of the E911 system is not functioning properly. The SSC/MAC should verify with the PSAP attendant that the equipment's primary function is answering E911 calls. If it is, the SSC/MAC should request a dispatch SSIM/I&M. If the equipment is not primarily used for E911, then the SSC/MAC should advise PSAP to contact their CPE vendor. Note: These troubles can be quite confusing when the PSAP has vendor equipment mixed in with equipment that the BOC maintains. The Marketing representative should provide the SSC/MAC information concerning any unusual or exception items where the PSAP should contact their vendor. This information should be included in the PSAP profile sheets. ANI or ALI controller down: When the host computer sees the PSAP equipment down and it does not come back up, the MMOC will report the trouble to the SSC/MAC; the equipment is down at the PSAP, a dispatch will be required. PSAP link (circuit) down: The MMOC will provide the SSC/MAC with the circuit ID that the Host computer indicates in trouble. Although each PSAP has two circuits, when either circuit is down the condition must be treated as an emergency since failure of the second circuit will cause the PSAP to be isolated. Any problems that the MMOC identifies from the Node location to the Host computer will be handled directly with the appropriate MMOC(s)/CCNC. Note: The customer will call only when a problem is apparent to the PSAP. When only one circuit is down to the PSAP, the customer may not be aware there is a trouble, even though there is one link down, notification should appear on the PSAP screen. Troubles called into the SSC/MAC from the MMOC or other company employee should not be closed out by calling the PSAP since it may result in the customer responding that they do not have a trouble. These reports can only be closed out by receiving information that the trouble was fixed and by checking with the company employee that reported the trouble. The MMOC personnel will be able to verify that the trouble has cleared by reviewing a printout from the host. When the CRSAB receives a subscriber complaint (i.e., cannot dial 911) the RSA should obtain as much information as possible while the customer is on the line. For example, what happened when the subscriber dialed 911? The report is automatically directed to the IMC for subscriber line testing. When no line trouble is found, the IMC will refer the trouble condition to the SSC/MAC. The SSC/MAC will contact Customer Services E911 Group and verify that the subscriber should be able to call 911 and obtain the ESN. The SSC/MAC will verify the ESN via 2SCCS. When both verifications match, the SSC/MAC will refer the report to the SCC responsible for the 911 tandem office for investigation and resolution. The MAC is responsible for tracking the trouble and informing the IMC when it is resolved. For more information, please refer to E911 Glossary of Terms. End of Phrack File _____________________________________ The reader is forgiven if he or she was entirely unable to read this document. John Perry Barlow had a great deal of fun at its expense, in "Crime and Puzzlement:" "Bureaucrat-ese of surpassing opacity. . . . To read the whole thing straight through without entering coma requires either a machine or a human who has too much practice thinking like one. Anyone who can understand it fully and fluidly had altered his consciousness beyond the ability to ever again read Blake, Whitman, or Tolstoy. . . . the document contains little of interest to anyone who is not a student of advanced organizational sclerosis." With the Document itself to hand, however, exactly as it was published (in its six-page edited form) in Phrack, the reader may be able to verify a few statements of fact about its nature. First, there is no software, no computer code, in the Document. It is not computer-programming language like FORTRAN or C++, it is English; all the sentences have nouns and verbs and punctuation. It does not explain how to break into the E911 system. It does not suggest ways to destroy or damage the E911 system. There are no access codes in the Document. There are no computer passwords. It does not explain how to steal long distance service. It does not explain how to break in to telco switching stations. There is nothing in it about using a personal computer or a modem for any purpose at all, good or bad. Close study will reveal that this document is not about machinery. The E911 Document is about ADMINISTRATION. It describes how one creates and administers certain units of telco bureaucracy: Special Service Centers and Major Account Centers (SSC/MAC). It describes how these centers should distribute responsibility for the E911 service, to other units of telco bureaucracy, in a chain of command, a formal hierarchy. It describes who answers customer complaints, who screens calls, who reports equipment failures, who answers those reports, who handles maintenance, who chairs subcommittees, who gives orders, who follows orders, WHO tells WHOM what to do. The Document is not a "roadmap" to computers. The Document is a roadmap to PEOPLE. As an aid to breaking into computer systems, the Document is USELESS. As an aid to harassing and deceiving telco people, however, the Document might prove handy (especially with its Glossary, which I have not included). An intense and protracted study of this Document and its Glossary, combined with many other such documents, might teach one to speak like a telco employee. And telco people live by SPEECH--they live by phone communication. If you can mimic their language over the phone, you can "social-engineer" them. If you can con telco people, you can wreak havoc among them. You can force them to no longer trust one another; you can break the telephonic ties that bind their community; you can make them paranoid. And people will fight harder to defend their community than they will fight to defend their individual selves. This was the genuine, gut-level threat posed by Phrack magazine. The real struggle was over the control of telco language, the control of telco knowledge. It was a struggle to defend the social "membrane of differentiation" that forms the walls of the telco community's ivory tower --the special jargon that allows telco professionals to recognize one another, and to exclude charlatans, thieves, and upstarts. And the prosecution brought out this fact. They repeatedly made reference to the threat posed to telco professionals by hackers using "social engineering." However, Craig Neidorf was not on trial for learning to speak like a professional telecommunications expert. Craig Neidorf was on trial for access device fraud and transportation of stolen property. He was on trial for stealing a document that was purportedly highly sensitive and purportedly worth tens of thousands of dollars. # John Nagle read the E911 Document. He drew his own conclusions. And he presented Zenner and his defense team with an overflowing box of similar material, drawn mostly from Stanford University's engineering libraries. During the trial, the defense team--Zenner, half-a-dozen other attorneys, Nagle, Neidorf, and computer-security expert Dorothy Denning, all pored over the E911 Document line-by-line. On the afternoon of July 25, 1990, Zenner began to cross-examine a woman named Billie Williams, a service manager for Southern Bell in Atlanta. Ms. Williams had been responsible for the E911 Document. (She was not its author--its original "author" was a Southern Bell staff manager named Richard Helms. However, Mr. Helms should not bear the entire blame; many telco staff people and maintenance personnel had amended the Document. It had not been so much "written" by a single author, as built by committee out of concrete-blocks of jargon.) Ms. Williams had been called as a witness for the prosecution, and had gamely tried to explain the basic technical structure of the E911 system, aided by charts. Now it was Zenner's turn. He first established that the "proprietary stamp" that BellSouth had used on the E911 Document was stamped on EVERY SINGLE DOCUMENT that BellSouth wrote-- THOUSANDS of documents. "We do not publish anything other than for our own company," Ms. Williams explained. "Any company document of this nature is considered proprietary." Nobody was in charge of singling out special high-security publications for special high-security protection. They were ALL special, no matter how trivial, no matter what their subject matter-- the stamp was put on as soon as any document was written, and the stamp was never removed. Zenner now asked whether the charts she had been using to explain the mechanics of E911 system were "proprietary," too. Were they PUBLIC INFORMATION, these charts, all about PSAPs, ALIs, nodes, local end switches? Could he take the charts out in the street and show them to anybody, "without violating some proprietary notion that BellSouth has?" Ms Williams showed some confusion, but finally areed that the charts were, in fact, public. "But isn't this what you said was basically what appeared in Phrack?" Ms. Williams denied this. Zenner now pointed out that the E911 Document as published in Phrack was only half the size of the original E911 Document (as Prophet had purloined it). Half of it had been deleted--edited by Neidorf. Ms. Williams countered that "Most of the information that is in the text file is redundant." Zenner continued to probe. Exactly what bits of knowledge in the Document were, in fact, unknown to the public? Locations of E911 computers? Phone numbers for telco personnel? Ongoing maintenance subcommittees? Hadn't Neidorf removed much of this? Then he pounced. "Are you familiar with Bellcore Technical Reference Document TR-TSY-000350?" It was, Zenner explained, officially titled "E911 Public Safety Answering Point Interface Between 1-1AESS Switch and Customer Premises Equipment." It contained highly detailed and specific technical information about the E911 System. It was published by Bellcore and publicly available for about $20. He showed the witness a Bellcore catalog which listed thousands of documents from Bellcore and from all the Baby Bells, BellSouth included. The catalog, Zenner pointed out, was free. Anyone with a credit card could call the Bellcore toll-free 800 number and simply order any of these documents, which would be shipped to any customer without question. Including, for instance, "BellSouth E911 Service Interfaces to Customer Premises Equipment at a Public Safety Answering Point." Zenner gave the witness a copy of "BellSouth E911 Service Interfaces," which cost, as he pointed out, $13, straight from the catalog. "Look at it carefully," he urged Ms. Williams, "and tell me if it doesn't contain about twice as much detailed information about the E911 system of BellSouth than appeared anywhere in Phrack." "You want me to. . . ." Ms. Williams trailed off. "I don't understand." "Take a careful look," Zenner persisted. "Take a look at that document, and tell me when you're done looking at it if, indeed, it doesn't contain much more detailed information about the E911 system than appeared in Phrack." "Phrack wasn't taken from this," Ms. Williams said. "Excuse me?" said Zenner. "Phrack wasn't taken from this." "I can't hear you," Zenner said. "Phrack was not taken from this document. I don't understand your question to me." "I guess you don't," Zenner said. At this point, the prosecution's case had been gutshot. Ms. Williams was distressed. Her confusion was quite genuine. Phrack had not been taken from any publicly available Bellcore document. Phrack's E911 Document had been stolen from her own company's computers, from her own company's text files, that her own colleagues had written, and revised, with much labor. But the "value" of the Document had been blown to smithereens. It wasn't worth eighty grand. According to Bellcore it was worth thirteen bucks. And the looming menace that it supposedly posed had been reduced in instants to a scarecrow. Bellcore itself was selling material far more detailed and "dangerous," to anybody with a credit card and a phone. Actually, Bellcore was not giving this information to just anybody. They gave it to ANYBODY WHO ASKED, but not many did ask. Not many people knew that Bellcore had a free catalog and an 800 number. John Nagle knew, but certainly the average teenage phreak didn't know. "Tuc," a friend of Neidorf's and sometime Phrack contributor, knew, and Tuc had been very helpful to the defense, behind the scenes. But the Legion of Doom didn't know--otherwise, they would never have wasted so much time raiding dumpsters. Cook didn't know. Foley didn't know. Kluepfel didn't know. The right hand of Bellcore knew not what the left hand was doing. The right hand was battering hackers without mercy, while the left hand was distributing Bellcore's intellectual property to anybody who was interested in telephone technical trivia--apparently, a pathetic few. The digital underground was so amateurish and poorly organized that they had never discovered this heap of unguarded riches. The ivory tower of the telcos was so wrapped-up in the fog of its own technical obscurity that it had left all the windows open and flung open the doors. No one had even noticed. Zenner sank another nail in the coffin. He produced a printed issue of Telephone Engineer & Management, a prominent industry journal that comes out twice a month and costs $27 a year. This particular issue of TE&M, called "Update on 911," featured a galaxy of technical details on 911 service and a glossary far more extensive than Phrack's. The trial rumbled on, somehow, through its own momentum. Tim Foley testified about his interrogations of Neidorf. Neidorf's written admission that he had known the E911 Document was pilfered was officially read into the court record. An interesting side issue came up: "Terminus" had once passed Neidorf a piece of UNIX AT&T software, a log-in sequence, that had been cunningly altered so that it could trap passwords. The UNIX software itself was illegally copied AT&T property, and the alterations "Terminus" had made to it, had transformed it into a device for facilitating computer break-ins. Terminus himself would eventually plead guilty to theft of this piece of software, and the Chicago group would send Terminus to prison for it. But it was of dubious relevance in the Neidorf case. Neidorf hadn't written the program. He wasn't accused of ever having used it. And Neidorf wasn't being charged with software theft or owning a password trapper. On the next day, Zenner took the offensive. The civil libertarians now had their own arcane, untried legal weaponry to launch into action-- the Electronic Communications Privacy Act of 1986, 18 US Code, Section 2701 et seq. Section 2701 makes it a crime to intentionally access without authorization a facility in which an electronic communication service is provided--it is, at heart, an anti-bugging and anti-tapping law, intended to carry the traditional protections of telephones into other electronic channels of communication. While providing penalties for amateur snoops, however, Section 2703 of the ECPA also lays some formal difficulties on the bugging and tapping activities of police. The Secret Service, in the person of Tim Foley, had served Richard Andrews with a federal grand jury subpoena, in their pursuit of Prophet, the E911 Document, and the Terminus software ring. But according to the Electronic Communications Privacy Act, a "provider of remote computing service" was legally entitled to "prior notice" from the government if a subpoena was used. Richard Andrews and his basement UNIX node, Jolnet, had not received any "prior notice." Tim Foley had purportedly violated the ECPA and committed an electronic crime! Zenner now sought the judge's permission to cross-examine Foley on the topic of Foley's own electronic misdeeds. Cook argued that Richard Andrews' Jolnet was a privately owned bulletin board, and not within the purview of ECPA. Judge Bua granted the motion of the government to prevent cross-examination on that point, and Zenner's offensive fizzled. This, however, was the first direct assault on the legality of the actions of the Computer Fraud and Abuse Task Force itself-- the first suggestion that they themselves had broken the law, and might, perhaps, be called to account. Zenner, in any case, did not really need the ECPA. Instead, he grilled Foley on the glaring contradictions in the supposed value of the E911 Document. He also brought up the embarrassing fact that the supposedly red-hot E911 Document had been sitting around for months, in Jolnet, with Kluepfel's knowledge, while Kluepfel had done nothing about it. In the afternoon, the Prophet was brought in to testify for the prosecution. (The Prophet, it will be recalled, had also been indicted in the case as partner in a fraud scheme with Neidorf.) In Atlanta, the Prophet had already pled guilty to one charge of conspiracy, one charge of wire fraud and one charge of interstate transportation of stolen property. The wire fraud charge, and the stolen property charge, were both directly based on the E911 Document. The twenty-year-old Prophet proved a sorry customer, answering questions politely but in a barely audible mumble, his voice trailing off at the ends of sentences. He was constantly urged to speak up. Cook, examining Prophet, forced him to admit that he had once had a "drug problem," abusing amphetamines, marijuana, cocaine, and LSD. This may have established to the jury that "hackers" are, or can be, seedy lowlife characters, but it may have damaged Prophet's credibility somewhat. Zenner later suggested that drugs might have damaged Prophet's memory. The interesting fact also surfaced that Prophet had never physically met Craig Neidorf. He didn't even know Neidorf's last name--at least, not until the trial. Prophet confirmed the basic facts of his hacker career. He was a member of the Legion of Doom. He had abused codes, he had broken into switching stations and re-routed calls, he had hung out on pirate bulletin boards. He had raided the BellSouth AIMSX computer, copied the E911 Document, stored it on Jolnet, mailed it to Neidorf. He and Neidorf had edited it, and Neidorf had known where it came from. Zenner, however, had Prophet confirm that Neidorf was not a member of the Legion of Doom, and had not urged Prophet to break into BellSouth computers. Neidorf had never urged Prophet to defraud anyone, or to steal anything. Prophet also admitted that he had never known Neidorf to break in to any computer. Prophet said that no one in the Legion of Doom considered Craig Neidorf a "hacker" at all. Neidorf was not a UNIX maven, and simply lacked the necessary skill and ability to break into computers. Neidorf just published a magazine. On Friday, July 27, 1990, the case against Neidorf collapsed. Cook moved to dismiss the indictment, citing "information currently available to us that was not available to us at the inception of the trial." Judge Bua praised the prosecution for this action, which he described as "very responsible," then dismissed a juror and declared a mistrial. Neidorf was a free man. His defense, however, had cost himself and his family dearly. Months of his life had been consumed in anguish; he had seen his closest friends shun him as a federal criminal. He owed his lawyers over a hundred thousand dollars, despite a generous payment to the defense by Mitch Kapor. Neidorf was not found innocent. The trial was simply dropped. Nevertheless, on September 9, 1991, Judge Bua granted Neidorf's motion for the "expungement and sealing" of his indictment record. The United States Secret Service was ordered to delete and destroy all fingerprints, photographs, and other records of arrest or processing relating to Neidorf's indictment, including their paper documents and their computer records. Neidorf went back to school, blazingly determined to become a lawyer. Having seen the justice system at work, Neidorf lost much of his enthusiasm for merely technical power. At this writing, Craig Neidorf is working in Washington as a salaried researcher for the American Civil Liberties Union. # The outcome of the Neidorf trial changed the EFF from voices-in-the-wilderness to the media darlings of the new frontier. Legally speaking, the Neidorf case was not a sweeping triumph for anyone concerned. No constitutional principles had been established. The issues of "freedom of the press" for electronic publishers remained in legal limbo. There were public misconceptions about the case. Many people thought Neidorf had been found innocent and relieved of all his legal debts by Kapor. The truth was that the government had simply dropped the case, and Neidorf's family had gone deeply into hock to support him. But the Neidorf case did provide a single, devastating, public sound-bite: THE FEDS SAID IT WAS WORTH EIGHTY GRAND, AND IT WAS ONLY WORTH THIRTEEN BUCKS. This is the Neidorf case's single most memorable element. No serious report of the case missed this particular element. Even cops could not read this without a wince and a shake of the head. It left the public credibility of the crackdown agents in tatters. The crackdown, in fact, continued, however. Those two charges against Prophet, which had been based on the E911 Document, were quietly forgotten at his sentencing--even though Prophet had already pled guilty to them. Georgia federal prosecutors strongly argued for jail time for the Atlanta Three, insisting on "the need to send a message to the community," "the message that hackers around the country need to hear." There was a great deal in their sentencing memorandum about the awful things that various other hackers had done (though the Atlanta Three themselves had not, in fact, actually committed these crimes). There was also much speculation about the awful things that the Atlanta Three MIGHT have done and WERE CAPABLE of doing (even though they had not, in fact, actually done them). The prosecution's argument carried the day. The Atlanta Three were sent to prison: Urvile and Leftist both got 14 months each, while Prophet (a second offender) got 21 months. The Atlanta Three were also assessed staggering fines as "restitution": $233,000 each. BellSouth claimed that the defendants had "stolen" "approximately $233,880 worth" of "proprietary computer access information"-- specifically, $233,880 worth of computer passwords and connect addresses. BellSouth's astonishing claim of the extreme value of its own computer passwords and addresses was accepted at face value by the Georgia court. Furthermore (as if to emphasize its theoretical nature) this enormous sum was not divvied up among the Atlanta Three, but each of them had to pay all of it. A striking aspect of the sentence was that the Atlanta Three were specifically forbidden to use computers, except for work or under supervision. Depriving hackers of home computers and modems makes some sense if one considers hackers as "computer addicts," but EFF, filing an amicus brief in the case, protested that this punishment was unconstitutional-- it deprived the Atlanta Three of their rights of free association and free expression through electronic media. Terminus, the "ultimate hacker," was finally sent to prison for a year through the dogged efforts of the Chicago Task Force. His crime, to which he pled guilty, was the transfer of the UNIX password trapper, which was officially valued by AT&T at $77,000, a figure which aroused intense skepticism among those familiar with UNIX "login.c" programs. The jailing of Terminus and the Atlanta Legionnaires of Doom, however, did not cause the EFF any sense of embarrassment or defeat. On the contrary, the civil libertarians were rapidly gathering strength. An early and potent supporter was Senator Patrick Leahy, Democrat from Vermont, who had been a Senate sponsor of the Electronic Communications Privacy Act. Even before the Neidorf trial, Leahy had spoken out in defense of hacker-power and freedom of the keyboard: "We cannot unduly inhibit the inquisitive 13-year-old who, if left to experiment today, may tomorrow develop the telecommunications or computer technology to lead the United States into the 21st century. He represents our future and our best hope to remain a technologically competitive nation." It was a handsome statement, rendered perhaps rather more effective by the fact that the crackdown raiders DID NOT HAVE any Senators speaking out for THEM. On the contrary, their highly secretive actions and tactics, all "sealed search warrants" here and "confidential ongoing investigations" there, might have won them a burst of glamorous publicity at first, but were crippling them in the on-going propaganda war. Gail Thackeray was reduced to unsupported bluster: "Some of these people who are loudest on the bandwagon may just slink into the background," she predicted in Newsweek--when all the facts came out, and the cops were vindicated. But all the facts did not come out. Those facts that did, were not very flattering. And the cops were not vindicated. And Gail Thackeray lost her job. By the end of 1991, William Cook had also left public employment. 1990 had belonged to the crackdown, but by '91 its agents were in severe disarray, and the libertarians were on a roll. People were flocking to the cause. A particularly interesting ally had been Mike Godwin of Austin, Texas. Godwin was an individual almost as difficult to describe as Barlow; he had been editor of the student newspaper of the University of Texas, and a computer salesman, and a programmer, and in 1990 was back in law school, looking for a law degree. Godwin was also a bulletin board maven. He was very well-known in the Austin board community under his handle "Johnny Mnemonic," which he adopted from a cyberpunk science fiction story by William Gibson. Godwin was an ardent cyberpunk science fiction fan. As a fellow Austinite of similar age and similar interests, I myself had known Godwin socially for many years. When William Gibson and myself had been writing our collaborative SF novel, The Difference Engine, Godwin had been our technical advisor in our effort to link our Apple word-processors from Austin to Vancouver. Gibson and I were so pleased by his generous expert help that we named a character in the novel "Michael Godwin" in his honor. The handle "Mnemonic" suited Godwin very well. His erudition and his mastery of trivia were impressive to the point of stupor; his ardent curiosity seemed insatiable, and his desire to debate and argue seemed the central drive of his life. Godwin had even started his own Austin debating society, wryly known as the "Dull Men's Club." In person, Godwin could be overwhelming; a flypaper-brained polymath who could not seem to let any idea go. On bulletin boards, however, Godwin's closely reasoned, highly grammatical, erudite posts suited the medium well, and he became a local board celebrity. Mike Godwin was the man most responsible for the public national exposure of the Steve Jackson case. The Izenberg seizure in Austin had received no press coverage at all. The March 1 raids on Mentor, Bloodaxe, and Steve Jackson Games had received a brief front-page splash in the front page of the Austin American-Statesman, but it was confused and ill-informed: the warrants were sealed, and the Secret Service wasn't talking. Steve Jackson seemed doomed to obscurity. Jackson had not been arrested; he was not charged with any crime; he was not on trial. He had lost some computers in an ongoing investigation--so what? Jackson tried hard to attract attention to the true extent of his plight, but he was drawing a blank; no one in a position to help him seemed able to get a mental grip on the issues. Godwin, however, was uniquely, almost magically, qualified to carry Jackson's case to the outside world. Godwin was a board enthusiast, a science fiction fan, a former journalist, a computer salesman, a lawyer-to-be, and an Austinite. Through a coincidence yet more amazing, in his last year of law school Godwin had specialized in federal prosecutions and criminal procedure. Acting entirely on his own, Godwin made up a press packet which summarized the issues and provided useful contacts for reporters. Godwin's behind-the-scenes effort (which he carried out mostly to prove a point in a local board debate) broke the story again in the Austin American-Statesman and then in Newsweek. Life was never the same for Mike Godwin after that. As he joined the growing civil liberties debate on the Internet, it was obvious to all parties involved that here was one guy who, in the midst of complete murk and confusion, GENUINELY UNDERSTOOD EVERYTHING HE WAS TALKING ABOUT. The disparate elements of Godwin's dilettantish existence suddenly fell together as neatly as the facets of a Rubik's cube. When the time came to hire a full-time EFF staff attorney, Godwin was the obvious choice. He took the Texas bar exam, left Austin, moved to Cambridge, became a full-time, professional, computer civil libertarian, and was soon touring the nation on behalf of EFF, delivering well-received addresses on the issues to crowds as disparate as academics, industrialists, science fiction fans, and federal cops. Michael Godwin is currently the chief legal counsel of the Electronic Frontier Foundation in Cambridge, Massachusetts. # Another early and influential participant in the controversy was Dorothy Denning. Dr. Denning was unique among investigators of the computer underground in that she did not enter the debate with any set of politicized motives. She was a professional cryptographer and computer security expert whose primary interest in hackers was SCHOLARLY. She had a B.A. and M.A. in mathematics, and a Ph.D. in computer science from Purdue. She had worked for SRI International, the California think-tank that was also the home of computer-security maven Donn Parker, and had authored an influential text called Cryptography and Data Security. In 1990, Dr. Denning was working for Digital Equipment Corporation in their Systems Reseach Center. Her husband, Peter Denning, was also a computer security expert, working for NASA's Research Institute for Advanced Computer Science. He had edited the well-received Computers Under Attack: Intruders, Worms and Viruses. Dr. Denning took it upon herself to contact the digital underground, more or less with an anthropological interest. There she discovered that these computer-intruding hackers, who had been characterized as unethical, irresponsible, and a serious danger to society, did in fact have their own subculture and their own rules. They were not particularly well-considered rules, but they were, in fact, rules. Basically, they didn't take money and they didn't break anything. Her dispassionate reports on her researches did a great deal to influence serious-minded computer professionals--the sort of people who merely rolled their eyes at the cyberspace rhapsodies of a John Perry Barlow. For young hackers of the digital underground, meeting Dorothy Denning was a genuinely mind-boggling experience. Here was this neatly coiffed, conservatively dressed, dainty little personage, who reminded most hackers of their moms or their aunts. And yet she was an IBM systems programmer with profound expertise in computer architectures and high-security information flow, who had personal friends in the FBI and the National Security Agency. Dorothy Denning was a shining example of the American mathematical intelligentsia, a genuinely brilliant person from the central ranks of the computer-science elite. And here she was, gently questioning twenty-year-old hairy-eyed phone-phreaks over the deeper ethical implications of their behavior. Confronted by this genuinely nice lady, most hackers sat up very straight and did their best to keep the anarchy-file stuff down to a faint whiff of brimstone. Nevertheless, the hackers WERE in fact prepared to seriously discuss serious issues with Dorothy Denning. They were willing to speak the unspeakable and defend the indefensible, to blurt out their convictions that information cannot be owned, that the databases of governments and large corporations were a threat to the rights and privacy of individuals. Denning's articles made it clear to many that "hacking" was not simple vandalism by some evil clique of psychotics. "Hacking" was not an aberrant menace that could be charmed away by ignoring it, or swept out of existence by jailing a few ringleaders. Instead, "hacking" was symptomatic of a growing, primal struggle over knowledge and power in the age of information. Denning pointed out that the attitude of hackers were at least partially shared by forward-looking management theorists in the business community: people like Peter Drucker and Tom Peters. Peter Drucker, in his book The New Realities, had stated that "control of information by the government is no longer possible. Indeed, information is now transnational. Like money, it has no `fatherland.'" And management maven Tom Peters had chided large corporations for uptight, proprietary attitudes in his bestseller, Thriving on Chaos: "Information hoarding, especially by politically motivated, power-seeking staffs, had been commonplace throughout American industry, service and manufacturing alike. It will be an impossible millstone aroung the neck of tomorrow's organizations." Dorothy Denning had shattered the social membrane of the digital underground. She attended the Neidorf trial, where she was prepared to testify for the defense as an expert witness. She was a behind-the-scenes organizer of two of the most important national meetings of the computer civil libertarians. Though not a zealot of any description, she brought disparate elements of the electronic community into a surprising and fruitful collusion. Dorothy Denning is currently the Chair of the Computer Science Department at Georgetown University in Washington, DC. # There were many stellar figures in the civil libertarian community. There's no question, however, that its single most influential figure was Mitchell D. Kapor. Other people might have formal titles, or governmental positions, have more experience with crime, or with the law, or with the arcanities of computer security or constitutional theory. But by 1991 Kapor had transcended any such narrow role. Kapor had become "Mitch." Mitch had become the central civil-libertarian ad-hocrat. Mitch had stood up first, he had spoken out loudly, directly, vigorously and angrily, he had put his own reputation, and his very considerable personal fortune, on the line. By mid-'91 Kapor was the best-known advocate of his cause and was known PERSONALLY by almost every single human being in America with any direct influence on the question of civil liberties in cyberspace. Mitch had built bridges, crossed voids, changed paradigms, forged metaphors, made phone-calls and swapped business cards to such spectacular effect that it had become impossible for anyone to take any action in the "hacker question" without wondering what Mitch might think-- and say--and tell his friends. The EFF had simply NETWORKED the situation into an entirely new status quo. And in fact this had been EFF's deliberate strategy from the beginning. Both Barlow and Kapor loathed bureaucracies and had deliberately chosen to work almost entirely through the electronic spiderweb of "valuable personal contacts." After a year of EFF, both Barlow and Kapor had every reason to look back with satisfaction. EFF had established its own Internet node, "eff.org," with a well-stocked electronic archive of documents on electronic civil rights, privacy issues, and academic freedom. EFF was also publishing EFFector, a quarterly printed journal, as well as EFFector Online, an electronic newsletter with over 1,200 subscribers. And EFF was thriving on the Well. EFF had a national headquarters in Cambridge and a full-time staff. It had become a membership organization and was attracting grass-roots support. It had also attracted the support of some thirty civil-rights lawyers, ready and eager to do pro bono work in defense of the Constitution in Cyberspace. EFF had lobbied successfully in Washington and in Massachusetts to change state and federal legislation on computer networking. Kapor in particular had become a veteran expert witness, and had joined the Computer Science and Telecommunications Board of the National Academy of Science and Engineering. EFF had sponsored meetings such as "Computers, Freedom and Privacy" and the CPSR Roundtable. It had carried out a press offensive that, in the words of EFFector, "has affected the climate of opinion about computer networking and begun to reverse the slide into `hacker hysteria' that was beginning to grip the nation." It had helped Craig Neidorf avoid prison. And, last but certainly not least, the Electronic Frontier Foundation had filed a federal lawsuit in the name of Steve Jackson, Steve Jackson Games Inc., and three users of the Illuminati bulletin board system. The defendants were, and are, the United States Secret Service, William Cook, Tim Foley, Barbara Golden and Henry Kleupfel. The case, which is in pre-trial procedures in an Austin federal court as of this writing, is a civil action for damages to redress alleged violations of the First and Fourth Amendments to the United States Constitution, as well as the Privacy Protection Act of 1980 (42 USC 2000aa et seq.), and the Electronic Communications Privacy Act (18 USC 2510 et seq and 2701 et seq). EFF had established that it had credibility. It had also established that it had teeth. In the fall of 1991 I travelled to Massachusetts to speak personally with Mitch Kapor. It was my final interview for this book. # The city of Boston has always been one of the major intellectual centers of the American republic. It is a very old city by American standards, a place of skyscrapers overshadowing seventeenth-century graveyards, where the high-tech start-up companies of Route 128 co-exist with the hand-wrought pre-industrial grace of "Old Ironsides," the USS CONSTITUTION. The Battle of Bunker Hill, one of the first and bitterest armed clashes of the American Revolution, was fought in Boston's environs. Today there is a monumental spire on Bunker Hill, visible throughout much of the city. The willingness of the republican revolutionaries to take up arms and fire on their oppressors has left a cultural legacy that two full centuries have not effaced. Bunker Hill is still a potent center of American political symbolism, and the Spirit of '76 is still a potent image for those who seek to mold public opinion. Of course, not everyone who wraps himself in the flag is necessarily a patriot. When I visited the spire in September 1991, it bore a huge, badly-erased, spray-can grafitto around its bottom reading "BRITS OUT--IRA PROVOS." Inside this hallowed edifice was a glass-cased diorama of thousands of tiny toy soldiers, rebels and redcoats, fighting and dying over the green hill, the riverside marshes, the rebel trenchworks. Plaques indicated the movement of troops, the shiftings of strategy. The Bunker Hill Monument is occupied at its very center by the toy soldiers of a military war-game simulation. The Boston metroplex is a place of great universities, prominent among the Massachusetts Institute of Technology, where the term "computer hacker" was first coined. The Hacker Crackdown of 1990 might be interpreted as a political struggle among American cities: traditional strongholds of longhair intellectual liberalism, such as Boston, San Francisco, and Austin, versus the bare-knuckle industrial pragmatism of Chicago and Phoenix (with Atlanta and New York wrapped in internal struggle). The headquarters of the Electronic Frontier Foundation is on 155 Second Street in Cambridge, a Bostonian suburb north of the River Charles. Second Street has weedy sidewalks of dented, sagging brick and elderly cracked asphalt; large street-signs warn "NO PARKING DURING DECLARED SNOW EMERGENCY." This is an old area of modest manufacturing industries; the EFF is catecorner from the Greene Rubber Company. EFF's building is two stories of red brick; its large wooden windows feature gracefully arched tops and stone sills. The glass window beside the Second Street entrance bears three sheets of neatly laser-printed paper, taped against the glass. They read: ON Technology. EFF. KEI. "ON Technology" is Kapor's software company, which currently specializes in "groupware" for the Apple Macintosh computer. "Groupware" is intended to promote efficient social interaction among office-workers linked by computers. ON Technology's most successful software products to date are "Meeting Maker" and "Instant Update." "KEI" is Kapor Enterprises Inc., Kapor's personal holding company, the commercial entity that formally controls his extensive investments in other hardware and software corporations. "EFF" is a political action group--of a special sort. Inside, someone's bike has been chained to the handrails of a modest flight of stairs. A wall of modish glass brick separates this anteroom from the offices. Beyond the brick, there's an alarm system mounted on the wall, a sleek, complex little number that resembles a cross between a thermostat and a CD player. Piled against the wall are box after box of a recent special issue of Scientific American, "How to Work, Play, and Thrive in Cyberspace," with extensive coverage of electronic networking techniques and political issues, including an article by Kapor himself. These boxes are addressed to Gerard Van der Leun, EFF's Director of Communications, who will shortly mail those magazines to every member of the EFF. The joint headquarters of EFF, KEI, and ON Technology, which Kapor currently rents, is a modestly bustling place. It's very much the same physical size as Steve Jackson's gaming company. It's certainly a far cry from the gigantic gray steel-sided railway shipping barn, on the Monsignor O'Brien Highway, that is owned by Lotus Development Corporation. Lotus is, of course, the software giant that Mitchell Kapor founded in the late 70s. The software program Kapor co-authored, "Lotus 1-2-3," is still that company's most profitable product. "Lotus 1-2-3" also bears a singular distinction in the digital underground: it's probably the most pirated piece of application software in world history. Kapor greets me cordially in his own office, down a hall. Kapor, whose name is pronounced KAY-por, is in his early forties, married and the father of two. He has a round face, high forehead, straight nose, a slightly tousled mop of black hair peppered with gray. His large brown eyes are wideset, reflective, one might almost say soulful. He disdains ties, and commonly wears Hawaiian shirts and tropical prints, not so much garish as simply cheerful and just that little bit anomalous. There is just the whiff of hacker brimstone about Mitch Kapor. He may not have the hard-riding, hell-for-leather, guitar-strumming charisma of his Wyoming colleague John Perry Barlow, but there's something about the guy that still stops one short. He has the air of the Eastern city dude in the bowler hat, the dreamy, Longfellow-quoting poker shark who only HAPPENS to know the exact mathematical odds against drawing to an inside straight. Even among his computer-community colleagues, who are hardly known for mental sluggishness, Kapor strikes one forcefully as a very intelligent man. He speaks rapidly, with vigorous gestures, his Boston accent sometimes slipping to the sharp nasal tang of his youth in Long Island. Kapor, whose Kapor Family Foundation does much of his philanthropic work, is a strong supporter of Boston's Computer Museum. Kapor's interest in the history of his industry has brought him some remarkable curios, such as the "byte" just outside his office door. This "byte"-- eight digital bits--has been salvaged from the wreck of an electronic computer of the pre-transistor age. It's a standing gunmetal rack about the size of a small toaster-oven: with eight slots of hand-soldered breadboarding featuring thumb-sized vacuum tubes. If it fell off a table it could easily break your foot, but it was state-of-the-art computation in the 1940s. (It would take exactly 157,184 of these primordial toasters to hold the first part of this book.) There's also a coiling, multicolored, scaly dragon that some inspired techno-punk artist has cobbled up entirely out of transistors, capacitors, and brightly plastic-coated wiring. Inside the office, Kapor excuses himself briefly to do a little mouse-whizzing housekeeping on his personal Macintosh IIfx. If its giant screen were an open window, an agile person could climb through it without much trouble at all. There's a coffee-cup at Kapor's elbow, a memento of his recent trip to Eastern Europe, which has a black-and-white stencilled photo and the legend CAPITALIST FOOLS TOUR. It's Kapor, Barlow, and two California venture-capitalist luminaries of their acquaintance, four windblown, grinning Baby Boomer dudes in leather jackets, boots, denim, travel bags, standing on airport tarmac somewhere behind the formerly Iron Curtain. They look as if they're having the absolute time of their lives. Kapor is in a reminiscent mood. We talk a bit about his youth-- high school days as a "math nerd," Saturdays attending Columbia University's high-school science honors program, where he had his first experience programming computers. IBM 1620s, in 1965 and '66. "I was very interested," says Kapor, "and then I went off to college and got distracted by drugs sex and rock and roll, like anybody with half a brain would have then!" After college he was a progressive-rock DJ in Hartford, Connecticut, for a couple of years. I ask him if he ever misses his rock and roll days--if he ever wished he could go back to radio work. He shakes his head flatly. "I stopped thinking about going back to be a DJ the day after Altamont." Kapor moved to Boston in 1974 and got a job programming mainframes in COBOL. He hated it. He quit and became a teacher of transcendental meditation. (It was Kapor's long flirtation with Eastern mysticism that gave the world "Lotus.") In 1976 Kapor went to Switzerland, where the Transcendental Meditation movement had rented a gigantic Victorian hotel in St-Moritz. It was an all-male group--a hundred and twenty of them--determined upon Enlightenment or Bust. Kapor had given the transcendant his best shot. He was becoming disenchanted by "the nuttiness in the organization." "They were teaching people to levitate," he says, staring at the floor. His voice drops an octave, becomes flat. "THEY DON'T LEVITATE." Kapor chose Bust. He went back to the States and acquired a degree in counselling psychology. He worked a while in a hospital, couldn't stand that either. "My rep was," he says "a very bright kid with a lot of potential who hasn't found himself. Almost thirty. Sort of lost." Kapor was unemployed when he bought his first personal computer--an Apple II. He sold his stereo to raise cash and drove to New Hampshire to avoid the sales tax. "The day after I purchased it," Kapor tells me, "I was hanging out in a computer store and I saw another guy, a man in his forties, well-dressed guy, and eavesdropped on his conversation with the salesman. He didn't know anything about computers. I'd had a year programming. And I could program in BASIC. I'd taught myself. So I went up to him, and I actually sold myself to him as a consultant." He pauses. "I don't know where I got the nerve to do this. It was uncharacteristic. I just said, `I think I can help you, I've been listening, this is what you need to do and I think I can do it for you.' And he took me on! He was my first client! I became a computer consultant the first day after I bought the Apple II." Kapor had found his true vocation. He attracted more clients for his consultant service, and started an Apple users' group. A friend of Kapor's, Eric Rosenfeld, a graduate student at MIT, had a problem. He was doing a thesis on an arcane form of financial statistics, but could not wedge himself into the crowded queue for time on MIT's mainframes. (One might note at this point that if Mr. Rosenfeld had dishonestly broken into the MIT mainframes, Kapor himself might have never invented Lotus 1-2-3 and the PC business might have been set back for years!) Eric Rosenfeld did have an Apple II, however, and he thought it might be possible to scale the problem down. Kapor, as favor, wrote a program for him in BASIC that did the job. It then occurred to the two of them, out of the blue, that it might be possible to SELL this program. They marketed it themselves, in plastic baggies, for about a hundred bucks a pop, mail order. "This was a total cottage industry by a marginal consultant," Kapor says proudly. "That's how I got started, honest to God." Rosenfeld, who later became a very prominent figure on Wall Street, urged Kapor to go to MIT's business school for an MBA. Kapor did seven months there, but never got his MBA. He picked up some useful tools--mainly a firm grasp of the principles of accounting--and, in his own words, "learned to talk MBA." Then he dropped out and went to Silicon Valley. The inventors of VisiCalc, the Apple computer's premier business program, had shown an interest in Mitch Kapor. Kapor worked diligently for them for six months, got tired of California, and went back to Boston where they had better bookstores. The VisiCalc group had made the critical error of bringing in "professional management." "That drove them into the ground," Kapor says. "Yeah, you don't hear a lot about VisiCalc these days," I muse. Kapor looks surprised. "Well, Lotus. . . we BOUGHT it." "Oh. You BOUGHT it?" "Yeah." "Sort of like the Bell System buying Western Union?" Kapor grins. "Yep! Yep! Yeah, exactly!" Mitch Kapor was not in full command of the destiny of himself or his industry. The hottest software commodities of the early 1980s were COMPUTER GAMES--the Atari seemed destined to enter every teenage home in America. Kapor got into business software simply because he didn't have any particular feeling for computer games. But he was supremely fast on his feet, open to new ideas and inclined to trust his instincts. And his instincts were good. He chose good people to deal with-- gifted programmer Jonathan Sachs (the co-author of Lotus 1-2-3). Financial wizard Eric Rosenfeld, canny Wall Street analyst and venture capitalist Ben Rosen. Kapor was the founder and CEO of Lotus, one of the most spectacularly successful business ventures of the later twentieth century. He is now an extremely wealthy man. I ask him if he actually knows how much money he has. "Yeah," he says. "Within a percent or two." How much does he actually have, then? He shakes his head. "A lot. A lot. Not something I talk about. Issues of money and class are things that cut pretty close to the bone." I don't pry. It's beside the point. One might presume, impolitely, that Kapor has at least forty million--that's what he got the year he left Lotus. People who ought to know claim Kapor has about a hundred and fifty million, give or take a market swing in his stock holdings. If Kapor had stuck with Lotus, as his colleague friend and rival Bill Gates has stuck with his own software start-up, Microsoft, then Kapor would likely have much the same fortune Gates has-- somewhere in the neighborhood of three billion, give or take a few hundred million. Mitch Kapor has all the money he wants. Money has lost whatever charm it ever held for him--probably not much in the first place. When Lotus became too uptight, too bureaucratic, too far from the true sources of his own satisfaction, Kapor walked. He simply severed all connections with the company and went out the door. It stunned everyone--except those who knew him best. Kapor has not had to strain his resources to wreak a thorough transformation in cyberspace politics. In its first year, EFF's budget was about a quarter of a million dollars. Kapor is running EFF out of his pocket change. Kapor takes pains to tell me that he does not consider himself a civil libertarian per se. He has spent quite some time with true-blue civil libertarians lately, and there's a political-correctness to them that bugs him. They seem to him to spend entirely too much time in legal nitpicking and not enough vigorously exercising civil rights in the everyday real world. Kapor is an entrepreneur. Like all hackers, he prefers his involvements direct, personal, and hands-on. "The fact that EFF has a node on the Internet is a great thing. We're a publisher. We're a distributor of information." Among the items the eff.org Internet node carries is back issues of Phrack. They had an internal debate about that in EFF, and finally decided to take the plunge. They might carry other digital underground publications--but if they do, he says, "we'll certainly carry Donn Parker, and anything Gail Thackeray wants to put up. We'll turn it into a public library, that has the whole spectrum of use. Evolve in the direction of people making up their own minds." He grins. "We'll try to label all the editorials." Kapor is determined to tackle the technicalities of the Internet in the service of the public interest. "The problem with being a node on the Net today is that you've got to have a captive technical specialist. We have Chris Davis around, for the care and feeding of the balky beast! We couldn't do it ourselves!" He pauses. "So one direction in which technology has to evolve is much more standardized units, that a non-technical person can feel comfortable with. It's the same shift as from minicomputers to PCs. I can see a future in which any person can have a Node on the Net. Any person can be a publisher. It's better than the media we now have. It's possible. We're working actively." Kapor is in his element now, fluent, thoroughly in command in his material. "You go tell a hardware Internet hacker that everyone should have a node on the Net," he says, "and the first thing they're going to say is, `IP doesn't scale!'" ("IP" is the interface protocol for the Internet. As it currently exists, the IP software is simply not capable of indefinite expansion; it will run out of usable addresses, it will saturate.) "The answer," Kapor says, "is: evolve the protocol! Get the smart people together and figure out what to do. Do we add ID? Do we add new protocol? Don't just say, WE CAN'T DO IT." Getting smart people together to figure out what to do is a skill at which Kapor clearly excels. I counter that people on the Internet rather enjoy their elite technical status, and don't seem particularly anxious to democratize the Net. Kapor agrees, with a show of scorn. "I tell them that this is the snobbery of the people on the Mayflower looking down their noses at the people who came over ON THE SECOND BOAT! Just because they got here a year, or five years, or ten years before everybody else, that doesn't give them ownership of cyberspace! By what right?" I remark that the telcos are an electronic network, too, and they seem to guard their specialized knowledge pretty closely. Kapor ripostes that the telcos and the Internet are entirely different animals. "The Internet is an open system, everything is published, everything gets argued about, basically by anybody who can get in. Mostly, it's exclusive and elitist just because it's so difficult. Let's make it easier to use." On the other hand, he allows with a swift change of emphasis, the so-called elitists do have a point as well. "Before people start coming in, who are new, who want to make suggestions, and criticize the Net as `all screwed up'. . . . They should at least take the time to understand the culture on its own terms. It has its own history--show some respect for it. I'm a conservative, to that extent." The Internet is Kapor's paradigm for the future of telecommunications. The Internet is decentralized, non-hierarchical, almost anarchic. There are no bosses, no chain of command, no secret data. If each node obeys the general interface standards, there's simply no need for any central network authority. Wouldn't that spell the doom of AT&T as an institution? I ask. That prospect doesn't faze Kapor for a moment. "Their big advantage, that they have now, is that they have all of the wiring. But two things are happening. Anyone with right-of-way is putting down fiber--Southern Pacific Railroad, people like that--there's enormous `dark fiber' laid in." ("Dark Fiber" is fiber-optic cable, whose enormous capacity so exceeds the demands of current usage that much of the fiber still has no light-signals on it--it's still `dark,' awaiting future use.) "The other thing that's happening is the local-loop stuff is going to go wireless. Everyone from Bellcore to the cable TV companies to AT&T wants to put in these things called `personal communication systems.' So you could have local competition-- you could have multiplicity of people, a bunch of neighborhoods, sticking stuff up on poles. And a bunch of other people laying in dark fiber. So what happens to the telephone companies? There's enormous pressure on them from both sides. "The more I look at this, the more I believe that in a post-industrial, digital world, the idea of regulated monopolies is bad. People will look back on it and say that in the 19th and 20th centuries the idea of public utilities was an okay compromise. You needed one set of wires in the ground. It was too economically inefficient, otherwise. And that meant one entity running it. But now, with pieces being wireless--the connections are going to be via high-level interfaces, not via wires. I mean, ULTIMATELY there are going to be wires--but the wires are just a commodity. Fiber, wireless. You no longer NEED a utility." Water utilities? Gas utilities? Of course we still need those, he agrees. "But when what you're moving is information, instead of physical substances, then you can play by a different set of rules. We're evolving those rules now! Hopefully you can have a much more decentralized system, and one in which there's more competition in the marketplace. "The role of government will be to make sure that nobody cheats. The proverbial `level playing field.' A policy that prevents monopolization. It should result in better service, lower prices, more choices, and local empowerment." He smiles. "I'm very big on local empowerment." Kapor is a man with a vision. It's a very novel vision which he and his allies are working out in considerable detail and with great energy. Dark, cynical, morbid cyberpunk that I am, I cannot avoid considering some of the darker implications of "decentralized, nonhierarchical, locally empowered" networking. I remark that some pundits have suggested that electronic networking--faxes, phones, small-scale photocopiers--played a strong role in dissolving the power of centralized communism and causing the collapse of the Warsaw Pact. Socialism is totally discredited, says Kapor, fresh back from the Eastern Bloc. The idea that faxes did it, all by themselves, is rather wishful thinking. Has it occurred to him that electronic networking might corrode America's industrial and political infrastructure to the point where the whole thing becomes untenable, unworkable--and the old order just collapses headlong, like in Eastern Europe? "No," Kapor says flatly. "I think that's extraordinarily unlikely. In part, because ten or fifteen years ago, I had similar hopes about personal computers--which utterly failed to materialize." He grins wryly, then his eyes narrow. "I'm VERY opposed to techno-utopias. Every time I see one, I either run away, or try to kill it." It dawns on me then that Mitch Kapor is not trying to make the world safe for democracy. He certainly is not trying to make it safe for anarchists or utopians-- least of all for computer intruders or electronic rip-off artists. What he really hopes to do is make the world safe for future Mitch Kapors. This world of decentralized, small-scale nodes, with instant global access for the best and brightest, would be a perfect milieu for the shoestring attic capitalism that made Mitch Kapor what he is today. Kapor is a very bright man. He has a rare combination of visionary intensity with a strong practical streak. The Board of the EFF: John Barlow, Jerry Berman of the ACLU, Stewart Brand, John Gilmore, Steve Wozniak, and Esther Dyson, the doyenne of East-West computer entrepreneurism--share his gift, his vision, and his formidable networking talents. They are people of the 1960s, winnowed-out by its turbulence and rewarded with wealth and influence. They are some of the best and the brightest that the electronic community has to offer. But can they do it, in the real world? Or are they only dreaming? They are so few. And there is so much against them. I leave Kapor and his networking employees struggling cheerfully with the promising intricacies of their newly installed Macintosh System 7 software. The next day is Saturday. EFF is closed. I pay a few visits to points of interest downtown. One of them is the birthplace of the telephone. It's marked by a bronze plaque in a plinth of black-and-white speckled granite. It sits in the plaza of the John F. Kennedy Federal Building, the very place where Kapor was once fingerprinted by the FBI. The plaque has a bas-relief picture of Bell's original telephone. "BIRTHPLACE OF THE TELEPHONE," it reads. "Here, on June 2, 1875, Alexander Graham Bell and Thomas A. Watson first transmitted sound over wires. "This successful experiment was completed in a fifth floor garret at what was then 109 Court Street and marked the beginning of world-wide telephone service." 109 Court Street is long gone. Within sight of Bell's plaque, across a street, is one of the central offices of NYNEX, the local Bell RBOC, on 6 Bowdoin Square. I cross the street and circle the telco building, slowly, hands in my jacket pockets. It's a bright, windy, New England autumn day. The central office is a handsome 1940s-era megalith in late Art Deco, eight stories high. Parked outside the back is a power-generation truck. The generator strikes me as rather anomalous. Don't they already have their own generators in this eight-story monster? Then the suspicion strikes me that NYNEX must have heard of the September 17 AT&T power-outage which crashed New York City. Belt-and-suspenders, this generator. Very telco. Over the glass doors of the front entrance is a handsome bronze bas-relief of Art Deco vines, sunflowers, and birds, entwining the Bell logo and the legend NEW ENGLAND TELEPHONE AND TELEGRAPH COMPANY --an entity which no longer officially exists. The doors are locked securely. I peer through the shadowed glass. Inside is an official poster reading: "New England Telephone a NYNEX Company ATTENTION "All persons while on New England Telephone Company premises are required to visibly wear their identification cards (C.C.P. Section 2, Page 1). "Visitors, vendors, contractors, and all others are required to visibly wear a daily pass. "Thank you. Kevin C. Stanton. Building Security Coordinator." Outside, around the corner, is a pull-down ribbed metal security door, a locked delivery entrance. Some passing stranger has grafitti-tagged this door, with a single word in red spray-painted cursive: Fury # My book on the Hacker Crackdown is almost over now. I have deliberately saved the best for last. In February 1991, I attended the CPSR Public Policy Roundtable, in Washington, DC. CPSR, Computer Professionals for Social Responsibility, was a sister organization of EFF, or perhaps its aunt, being older and perhaps somewhat wiser in the ways of the world of politics. Computer Professionals for Social Responsibility began in 1981 in Palo Alto, as an informal discussion group of Californian computer scientists and technicians, united by nothing more than an electronic mailing list. This typical high-tech ad-hocracy received the dignity of its own acronym in 1982, and was formally incorporated in 1983. CPSR lobbied government and public alike with an educational outreach effort, sternly warning against any foolish and unthinking trust in complex computer systems. CPSR insisted that mere computers should never be considered a magic panacea for humanity's social, ethical or political problems. CPSR members were especially troubled about the stability, safety, and dependability of military computer systems, and very especially troubled by those systems controlling nuclear arsenals. CPSR was best-known for its persistent and well-publicized attacks on the scientific credibility of the Strategic Defense Initiative ("Star Wars"). In 1990, CPSR was the nation's veteran cyber-political activist group, with over two thousand members in twenty- one local chapters across the US. It was especially active in Boston, Silicon Valley, and Washington DC, where its Washington office sponsored the Public Policy Roundtable. The Roundtable, however, had been funded by EFF, which had passed CPSR an extensive grant for operations. This was the first large-scale, official meeting of what was to become the electronic civil libertarian community. Sixty people attended, myself included--in this instance, not so much as a journalist as a cyberpunk author. Many of the luminaries of the field took part: Kapor and Godwin as a matter of course. Richard Civille and Marc Rotenberg of CPSR. Jerry Berman of the ACLU. John Quarterman, author of The Matrix. Steven Levy, author of Hackers. George Perry and Sandy Weiss of Prodigy Services, there to network about the civil-liberties troubles their young commercial network was experiencing. Dr. Dorothy Denning. Cliff Figallo, manager of the Well. Steve Jackson was there, having finally found his ideal target audience, and so was Craig Neidorf, "Knight Lightning" himself, with his attorney, Sheldon Zenner. Katie Hafner, science journalist, and co-author of Cyberpunk: Outlaws and Hackers on the Computer Frontier. Dave Farber, ARPAnet pioneer and fabled Internet guru. Janlori Goldman of the ACLU's Project on Privacy and Technology. John Nagle of Autodesk and the Well. Don Goldberg of the House Judiciary Committee. Tom Guidoboni, the defense attorney in the Internet Worm case. Lance Hoffman, computer-science professor at The George Washington University. Eli Noam of Columbia. And a host of others no less distinguished. Senator Patrick Leahy delivered the keynote address, expressing his determination to keep ahead of the curve on the issue of electronic free speech. The address was well-received, and the sense of excitement was palpable. Every panel discussion was interesting--some were entirely compelling. People networked with an almost frantic interest. I myself had a most interesting and cordial lunch discussion with Noel and Jeanne Gayler, Admiral Gayler being a former director of the National Security Agency. As this was the first known encounter between an actual no-kidding cyberpunk and a chief executive of America's largest and best-financed electronic espionage apparat, there was naturally a bit of eyebrow-raising on both sides. Unfortunately, our discussion was off-the-record. In fact all the discussions at the CPSR were officially off-the-record, the idea being to do some serious networking in an atmosphere of complete frankness, rather than to stage a media circus. In any case, CPSR Roundtable, though interesting and intensely valuable, was as nothing compared to the truly mind-boggling event that transpired a mere month later. # "Computers, Freedom and Privacy." Four hundred people from every conceivable corner of America's electronic community. As a science fiction writer, I have been to some weird gigs in my day, but this thing is truly BEYOND THE PALE. Even "Cyberthon," Point Foundation's "Woodstock of Cyberspace" where Bay Area psychedelia collided headlong with the emergent world of computerized virtual reality, was like a Kiwanis Club gig compared to this astonishing do. The "electronic community" had reached an apogee. Almost every principal in this book is in attendance. Civil Libertarians. Computer Cops. The Digital Underground. Even a few discreet telco people. Colorcoded dots for lapel tags are distributed. Free Expression issues. Law Enforcement. Computer Security. Privacy. Journalists. Lawyers. Educators. Librarians. Programmers. Stylish punk-black dots for the hackers and phone phreaks. Almost everyone here seems to wear eight or nine dots, to have six or seven professional hats. It is a community. Something like Lebanon perhaps, but a digital nation. People who had feuded all year in the national press, people who entertained the deepest suspicions of one another's motives and ethics, are now in each others' laps. "Computers, Freedom and Privacy" had every reason in the world to turn ugly, and yet except for small irruptions of puzzling nonsense from the convention's token lunatic, a surprising bonhomie reigned. CFP was like a wedding-party in which two lovers, unstable bride and charlatan groom, tie the knot in a clearly disastrous matrimony. It is clear to both families--even to neighbors and random guests-- that this is not a workable relationship, and yet the young couple's desperate attraction can brook no further delay. They simply cannot help themselves. Crockery will fly, shrieks from their newlywed home will wake the city block, divorce waits in the wings like a vulture over the Kalahari, and yet this is a wedding, and there is going to be a child from it. Tragedies end in death; comedies in marriage. The Hacker Crackdown is ending in marriage. And there will be a child. From the beginning, anomalies reign. John Perry Barlow, cyberspace ranger, is here. His color photo in The New York Times Magazine, Barlow scowling in a grim Wyoming snowscape, with long black coat, dark hat, a Macintosh SE30 propped on a fencepost and an awesome frontier rifle tucked under one arm, will be the single most striking visual image of the Hacker Crackdown. And he is CFP's guest of honor-- along with Gail Thackeray of the FCIC! What on earth do they expect these dual guests to do with each other? Waltz? Barlow delivers the first address. Uncharacteristically, he is hoarse--the sheer volume of roadwork has worn him down. He speaks briefly, congenially, in a plea for conciliation, and takes his leave to a storm of applause. Then Gail Thackeray takes the stage. She's visibly nervous. She's been on the Well a lot lately. Reading those Barlow posts. Following Barlow is a challenge to anyone. In honor of the famous lyricist for the Grateful Dead, she announces reedily, she is going to read-- A POEM. A poem she has composed herself. It's an awful poem, doggerel in the rollicking meter of Robert W. Service's The Cremation of Sam McGee, but it is in fact, a poem. It's the Ballad of the Electronic Frontier! A poem about the Hacker Crackdown and the sheer unlikelihood of CFP. It's full of in-jokes. The score or so cops in the audience, who are sitting together in a nervous claque, are absolutely cracking-up. Gail's poem is the funniest goddamn thing they've ever heard. The hackers and civil-libs, who had this woman figured for Ilsa She-Wolf of the SS, are staring with their jaws hanging loosely. Never in the wildest reaches of their imagination had they figured Gail Thackeray was capable of such a totally off-the-wall move. You can see them punching their mental CONTROL-RESET buttons. Jesus! This woman's a hacker weirdo! She's JUST LIKE US! God, this changes everything! Al Bayse, computer technician for the FBI, had been the only cop at the CPSR Roundtable, dragged there with his arm bent by Dorothy Denning. He was guarded and tightlipped at CPSR Roundtable; a "lion thrown to the Christians." At CFP, backed by a claque of cops, Bayse suddenly waxes eloquent and even droll, describing the FBI's "NCIC 2000", a gigantic digital catalog of criminal records, as if he has suddenly become some weird hybrid of George Orwell and George Gobel. Tentatively, he makes an arcane joke about statistical analysis. At least a third of the crowd laughs aloud. "They didn't laugh at that at my last speech," Bayse observes. He had been addressing cops--STRAIGHT cops, not computer people. It had been a worthy meeting, useful one supposes, but nothing like THIS. There has never been ANYTHING like this. Without any prodding, without any preparation, people in the audience simply begin to ask questions. Longhairs, freaky people, mathematicians. Bayse is answering, politely, frankly, fully, like a man walking on air. The ballroom's atmosphere crackles with surreality. A female lawyer behind me breaks into a sweat and a hot waft of surprisingly potent and musky perfume flows off her pulse-points. People are giddy with laughter. People are interested, fascinated, their eyes so wide and dark that they seem eroticized. Unlikely daisy-chains form in the halls, around the bar, on the escalators: cops with hackers, civil rights with FBI, Secret Service with phone phreaks. Gail Thackeray is at her crispest in a white wool sweater with a tiny Secret Service logo. "I found Phiber Optik at the payphones, and when he saw my sweater, he turned into a PILLAR OF SALT!" she chortles. Phiber discusses his case at much length with his arresting officer, Don Delaney of the New York State Police. After an hour's chat, the two of them look ready to begin singing "Auld Lang Syne." Phiber finally finds the courage to get his worst complaint off his chest. It isn't so much the arrest. It was the CHARGE. Pirating service off 900 numbers. I'm a PROGRAMMER, Phiber insists. This lame charge is going to hurt my reputation. It would have been cool to be busted for something happening, like Section 1030 computer intrusion. Maybe some kind of crime that's scarcely been invented yet. Not lousy phone fraud. Phooey. Delaney seems regretful. He had a mountain of possible criminal charges against Phiber Optik. The kid's gonna plead guilty anyway. He's a first timer, they always plead. Coulda charged the kid with most anything, and gotten the same result in the end. Delaney seems genuinely sorry not to have gratified Phiber in this harmless fashion. Too late now. Phiber's pled already. All water under the bridge. Whaddya gonna do? Delaney's got a good grasp on the hacker mentality. He held a press conference after he busted a bunch of Masters of Deception kids. Some journo had asked him: "Would you describe these people as GENIUSES?" Delaney's deadpan answer, perfect: "No, I would describe these people as DEFENDANTS." Delaney busts a kid for hacking codes with repeated random dialling. Tells the press that NYNEX can track this stuff in no time flat nowadays, and a kid has to be STUPID to do something so easy to catch. Dead on again: hackers don't mind being thought of as Genghis Khan by the straights, but if there's anything that really gets 'em where they live, it's being called DUMB. Won't be as much fun for Phiber next time around. As a second offender he's gonna see prison. Hackers break the law. They're not geniuses, either. They're gonna be defendants. And yet, Delaney muses over a drink in the hotel bar, he has found it impossible to treat them as common criminals. Delaney knows criminals. These kids, by comparison, are clueless--there is just no crook vibe off of them, they don't smell right, they're just not BAD. Delaney has seen a lot of action. He did Vietnam. He's been shot at, he has shot people. He's a homicide cop from New York. He has the appearance of a man who has not only seen the shit hit the fan but has seen it splattered across whole city blocks and left to ferment for years. This guy has been around. He listens to Steve Jackson tell his story. The dreamy game strategist has been dealt a bad hand. He has played it for all he is worth. Under his nerdish SF-fan exterior is a core of iron. Friends of his say Steve Jackson believes in the rules, believes in fair play. He will never compromise his principles, never give up. "Steve," Delaney says to Steve Jackson, "they had some balls, whoever busted you. You're all right!" Jackson, stunned, falls silent and actually blushes with pleasure. Neidorf has grown up a lot in the past year. The kid is a quick study, you gotta give him that. Dressed by his mom, the fashion manager for a national clothing chain, Missouri college techie-frat Craig Neidorf out-dappers everyone at this gig but the toniest East Coast lawyers. The iron jaws of prison clanged shut without him and now law school beckons for Neidorf. He looks like a larval Congressman. Not a "hacker," our Mr. Neidorf. He's not interested in computer science. Why should he be? He's not interested in writing C code the rest of his life, and besides, he's seen where the chips fall. To the world of computer science he and Phrack were just a curiosity. But to the world of law. . . . The kid has learned where the bodies are buried. He carries his notebook of press clippings wherever he goes. Phiber Optik makes fun of Neidorf for a Midwestern geek, for believing that "Acid Phreak" does acid and listens to acid rock. Hell no. Acid's never done ACID! Acid's into ACID HOUSE MUSIC. Jesus. The very idea of doing LSD. Our PARENTS did LSD, ya clown. Thackeray suddenly turns upon Craig Neidorf the full lighthouse glare of her attention and begins a determined half-hour attempt to WIN THE BOY OVER. The Joan of Arc of Computer Crime is GIVING CAREER ADVICE TO KNIGHT LIGHTNING! "Your experience would be very valuable--a real asset," she tells him with unmistakeable sixty-thousand-watt sincerity. Neidorf is fascinated. He listens with unfeigned attention. He's nodding and saying yes ma'am. Yes, Craig, you too can forget all about money and enter the glamorous and horribly underpaid world of PROSECUTING COMPUTER CRIME! You can put your former friends in prison--ooops. . . . You cannot go on dueling at modem's length indefinitely. You cannot beat one another senseless with rolled-up press-clippings. Sooner or later you have to come directly to grips. And yet the very act of assembling here has changed the entire situation drastically. John Quarterman, author of The Matrix, explains the Internet at his symposium. It is the largest news network in the world, it is growing by leaps and bounds, and yet you cannot measure Internet because you cannot stop it in place. It cannot stop, because there is no one anywhere in the world with the authority to stop Internet. It changes, yes, it grows, it embeds itself across the post-industrial, postmodern world and it generates community wherever it touches, and it is doing this all by itself. Phiber is different. A very fin de siecle kid, Phiber Optik. Barlow says he looks like an Edwardian dandy. He does rather. Shaven neck, the sides of his skull cropped hip-hop close, unruly tangle of black hair on top that looks pomaded, he stays up till four a.m. and misses all the sessions, then hangs out in payphone booths with his acoustic coupler gutsily CRACKING SYSTEMS RIGHT IN THE MIDST OF THE HEAVIEST LAW ENFORCEMENT DUDES IN THE U.S., or at least PRETENDING to. . . . Unlike "Frank Drake." Drake, who wrote Dorothy Denning out of nowhere, and asked for an interview for his cheapo cyberpunk fanzine, and then started grilling her on her ethics. She was squirmin', too. . . . Drake, scarecrow-tall with his floppy blond mohawk, rotting tennis shoes and black leather jacket lettered ILLUMINATI in red, gives off an unmistakeable air of the bohemian literatus. Drake is the kind of guy who reads British industrial design magazines and appreciates William Gibson because the quality of the prose is so tasty. Drake could never touch a phone or a keyboard again, and he'd still have the nose-ring and the blurry photocopied fanzines and the sampled industrial music. He's a radical punk with a desktop-publishing rig and an Internet address. Standing next to Drake, the diminutive Phiber looks like he's been physically coagulated out of phone-lines. Born to phreak. Dorothy Denning approaches Phiber suddenly. The two of them are about the same height and body-build. Denning's blue eyes flash behind the round window-frames of her glasses. "Why did you say I was `quaint?'" she asks Phiber, quaintly. It's a perfect description but Phiber is nonplussed. . . "Well, I uh, you know. . . ." "I also think you're quaint, Dorothy," I say, novelist to the rescue, the journo gift of gab. . . . She is neat and dapper and yet there's an arcane quality to her, something like a Pilgrim Maiden behind leaded glass; if she were six inches high Dorothy Denning would look great inside a china cabinet. . .The Cryptographeress. . . The Cryptographrix. . .whatever. . . . Weirdly, Peter Denning looks just like his wife, you could pick this gentleman out of a thousand guys as the soulmate of Dorothy Denning. Wearing tailored slacks, a spotless fuzzy varsity sweater, and a neatly knotted academician's tie. . . . This fineboned, exquisitely polite, utterly civilized and hyperintelligent couple seem to have emerged from some cleaner and finer parallel universe, where humanity exists to do the Brain Teasers column in Scientific American. Why does this Nice Lady hang out with these unsavory characters? Because the time has come for it, that's why. Because she's the best there is at what she does. Donn Parker is here, the Great Bald Eagle of Computer Crime. . . . With his bald dome, great height, and enormous Lincoln-like hands, the great visionary pioneer of the field plows through the lesser mortals like an icebreaker. . . . His eyes are fixed on the future with the rigidity of a bronze statue. . . . Eventually, he tells his audience, all business crime will be computer crime, because businesses will do everything through computers. "Computer crime" as a category will vanish. In the meantime, passing fads will flourish and fail and evaporate. . . . Parker's commanding, resonant voice is sphinxlike, everything is viewed from some eldritch valley of deep historical abstraction. . . . Yes, they've come and they've gone, these passing flaps in the world of digital computation. . . . The radio-frequency emanation scandal. . . KGB and MI5 and CIA do it every day, it's easy, but nobody else ever has. . . . The salami-slice fraud, mostly mythical. . . . "Crimoids," he calls them. . . . Computer viruses are the current crimoid champ, a lot less dangerous than most people let on, but the novelty is fading and there's a crimoid vacuum at the moment, the press is visibly hungering for something more outrageous. . . . The Great Man shares with us a few speculations on the coming crimoids. . . . Desktop Forgery! Wow. . . . Computers stolen just for the sake of the information within them--data-napping! Happened in Britain a while ago, could be the coming thing. . . . Phantom nodes in the Internet! Parker handles his overhead projector sheets with an ecclesiastical air. . . . He wears a grey double-breasted suit, a light blue shirt, and a very quiet tie of understated maroon and blue paisley. . . . Aphorisms emerge from him with slow, leaden emphasis. . . . There is no such thing as an adequately secure computer when one faces a sufficiently powerful adversary. . . . Deterrence is the most socially useful aspect of security. . . . People are the primary weakness in all information systems. . . . The entire baseline of computer security must be shifted upward. . . . Don't ever violate your security by publicly describing your security measures. . . . People in the audience are beginning to squirm, and yet there is something about the elemental purity of this guy's philosophy that compels uneasy respect. . . . Parker sounds like the only sane guy left in the lifeboat, sometimes. The guy who can prove rigorously, from deep moral principles, that Harvey there, the one with the broken leg and the checkered past, is the one who has to be, err. . .that is, Mr. Harvey is best placed to make the necessary sacrifice for the security and indeed the very survival of the rest of this lifeboat's crew. . . . Computer security, Parker informs us mournfully, is a nasty topic, and we wish we didn't have to have it. . . . The security expert, armed with method and logic, must think--imagine-- everything that the adversary might do before the adversary might actually do it. It is as if the criminal's dark brain were an extensive subprogram within the shining cranium of Donn Parker. He is a Holmes whose Moriarty does not quite yet exist and so must be perfectly simulated. CFP is a stellar gathering, with the giddiness of a wedding. It is a happy time, a happy ending, they know their world is changing forever tonight, and they're proud to have been there to see it happen, to talk, to think, to help. And yet as night falls, a certain elegiac quality manifests itself, as the crowd gathers beneath the chandeliers with their wineglasses and dessert plates. Something is ending here, gone forever, and it takes a while to pinpoint it. It is the End of the Amateurs. 
15617	----	[Transcriber's Note: References to page numbers in table of contents and index removed, as well as the numbers themselves.] [Illustration: ALEXANDER GRAHAM BELL The Inventor of the Telephone.] Cyclopedia of Telephony and Telegraphy _A General Reference Work on_ TELEPHONY, SUBSTATIONS, PARTY-LINE SYSTEMS, PROTECTION, MANUAL SWITCHBOARDS, AUTOMATIC SYSTEMS, POWER PLANTS, SPECIAL SERVICE FEATURES, CONSTRUCTION, ENGINEERING, OPERATION, MAINTENANCE, TELEGRAPHY, WIRELESS TELEGRAPHY AND TELEPHONY, ETC. _Prepared by a Corps of_ TELEPHONE AND TELEGRAPH EXPERTS, AND ELECTRICAL ENGINEERS OF THE HIGHEST PROFESSIONAL STANDING _Illustrated with over Two Thousand Engravings_ FOUR VOLUMES CHICAGO AMERICAN SCHOOL OF CORRESPONDENCE 1919 Authors and Collaborators * * * * * KEMPSTER B. MILLER. M.E. Consulting Engineer and Telephone Expert Of the Firm of McMeen and Miller, Electrical Engineers and Patent Experts, Chicago American Institute of Electrical Engineers Western Society of Engineers * * * * * GEORGE W. PATTERSON, S.B., Ph.D. Head, Department of Electrical Engineering, University of Michigan * * * * * CHARLES THOM Chief of Quadruplex Department, Western Union Main Office, New York City * * * * * ROBERT ANDREWS MILLIKAN, Ph.D. Associate Professor of Physics, University of Chicago Member, Executive Council, American Physical Society * * * * * SAMUEL G. McMEEN Consulting Engineer and Telephone Expert Of the Firm of McMeen and Miller, Electrical Engineers and Patent Experts, Chicago American Institute of Electrical Engineers Western Society of Engineers * * * * * LAWRENCE K. SAGER, S.B., M.P.L. Patent Attorney and Electrical Expert Formerly Assistant Examiner, U.S. Patent Office * * * * * GLENN M. HOBBS, Ph.D. Secretary, American School of Correspondence Formerly Instructor in Physics, University of Chicago American Physical Society * * * * * CHARLES G. ASHLEY Electrical Engineer and Expert in Wireless Telegraphy and Telephony * * * * * A. FREDERICK COLLINS Editor, _Collins Wireless Bulletin_ Author of "Wireless Telegraphy, Its History, Theory, and Practice" * * * * * FRANCIS B. CROCKER, E.M., Ph.D. Head, Department of Electrical Engineering, Columbia University Past-President, American Institute of Electrical Engineers * * * * * MORTON ARENDT, E.E. Instructor in Electrical Engineering, Columbia University, New York * * * * * EDWARD B. WAITE Head, Instruction Department, American School of Correspondence American Society of Mechanical Engineers Western Society of Engineers * * * * * DAVID P. MORETON, B.S., E.E. Associate Professor of Electrical Engineering, Armour Institute of Technology American Institute of Electrical Engineers, * * * * * LEIGH S. KEITH, B.S. Managing Engineer with McMeen and Miller, Electrical Engineers and Patent Experts Chicago Associate Member, American Institute of Electrical Engineers * * * * * JESSIE M. SHEPHERD, A.B. Associate Editor, Textbook Department, American School of Correspondence * * * * * ERNEST L. WALLACE, B.S. Assistant Examiner, United States Patent Office, Washington, D. C. * * * * * GEORGE R. METCALFE, M.E. Editor, _American Institute of Electrical Engineers_ Formerly Head of Publication Department, Westinghouse Elec. & Mfg. Co. * * * * * J.P. SCHROETER Graduate, Munich Technical School Instructor in Electrical Engineering, American School of Correspondence * * * * * JAMES DIXON, E.E. American Institute of Electrical Engineers * * * * * HARRIS C. TROW, S.B., _Managing Editor_ Editor-in-Chief, Textbook Department, American School of Correspondence Authorities Consulted The editors have freely consulted the standard technical literature of America and Europe in the preparation of these volumes. They desire to express their indebtedness particularly to the following eminent authorities, whose well-known works should be in the library of every telephone and telegraph engineer. Grateful acknowledgment is here made also for the invaluable co-operation of the foremost engineering firms and manufacturers in making these volumes thoroughly representative of the very best and latest practice in the transmission of intelligence, also for the valuable drawings, data, suggestions, criticisms, and other courtesies. * * * * * ARTHUR E. KENNELY, D.Sc. Professor of Electrical Engineering, Harvard University. Joint Author of "The Electric Telephone." "The Electric Telegraph," "Alternating Currents," "Arc Lighting," "Electric Heating," "Electric Motors," "Electric Railways," "Incandescent Lighting," etc. * * * * * HENRY SMITH CARHART, A.M., LL.D. Professor of Physics and Director of the Physical Laboratory, University of Michigan. Author of "Primary Batteries," "Elements of Physics," "University Physics," "Electrical Measurements," "High School Physics," etc. * * * * * FRANCIS B. CROCKER, M.E., Ph.D. Head of Department of Electrical Engineering, Columbia University, New York; Past-President, American Institute of Electrical Engineers. Author of "Electric Lighting;" Joint Author of "Management of Electrical Machinery." * * * * * HORATIO A. FOSTER Consulting Engineer; Member of American Institute of Electrical Engineers; Member of American Society of Mechanical Engineers. Author of "Electrical Engineer's Pocket-Book." * * * * * WILLIAM S. FRANKLIN, M.S., D.Sc. Professor of Physics, Lehigh University. Joint Author of "The Elements of Electrical Engineering," "The Elements of Alternating Currents." * * * * * LAMAR LYNDON, B.E., M.E. Consulting Electrical Engineer; Associate Member of American Institute of Electrical Engineers; Member, American Electro-Chemical Society. Author of "Storage Battery Engineering." * * * * * ROBERT ANDREWS MILLIKAN, Ph.D. Professor of Physics, University of Chicago. Joint Author of "A First Course in Physics," "Electricity, Sound and Light," etc. * * * * * KEMPSTER B. MILLER, M.E. Consulting Engineer and Telephone Expert; of the Firm of McMeen and Miller, Electrical Engineers and Patent Experts, Chicago. Author of "American Telephone Practice." * * * * * WILLIAM H. PREECE Chief of the British Postal Telegraph. Joint Author of "Telegraphy," "A Manual of Telephony," etc.-- * * * * * LOUIS BELL, Ph.D. Consulting Electrical Engineer; Lecturer on Power Transmission, Massachusetts Institute of Technology. Author of "Electric Power Transmission," "Power Distribution for Electric Railways," "The Art of Illumination," "Wireless Telephony," etc. * * * * * OLIVER HEAVISIDE, F.R.S. Author of "Electro-Magnetic Theory," "Electrical Papers," etc. * * * * * SILVANUS P. THOMPSON, D.Sc, B.A., F.R.S., F.R.A.S. Principal and Professor of Physics in the City and Guilds of London Technical College. Author of "Electricity and Magnetism," "Dynamo-Electric Machinery," "Polyphase Electric Currents and Alternate-Current Motors," "The Electromagnet," etc. * * * * * ANDREW GRAY, M.A., F.R.S.E. Author of "Absolute Measurements in Electricity and Magnetism." * * * * * ALBERT CUSHING CREHORE, A.B., Ph.D. Electrical Engineer; Assistant Professor of Physics, Dartmouth College; Formerly instructor in Physics, Cornell University. Author of "Synchronous and Other Multiple Telegraphs;" Joint Author of "Alternating Currents." * * * * * J. J. THOMSON, D.Sc, LL.D., Ph.D., F.R.S. Fellow of Trinity College, Cambridge University; Cavendish Professor of Experimental Physics, Cambridge University. Author of "The Conduction of Electricity through Gases," "Electricity and Matter." * * * * * FREDERICK BEDELL, Ph. D. Professor of Applied Electricity, Cornell University. Author of "The Principles of the Transformer;" Joint Author of "Alternating Currents." * * * * * DUGALD C. JACKSON, C.E. Head of Department of Electrical Engineering, Massachusetts Institute of Technology; Member, American Institute of Electrical Engineers, etc. Author of "A Textbook on Electromagnetism and the Construction of Dynamos;" Joint Author of "Alternating Currents and Alternating-Current Machinery." * * * * * MICHAEL IDVORSKY PUPIN, A.B., Sc.D., Ph.D. Professor of Electro-Mechanics, Columbia University, New York. Author of "Propagation of Long Electric Waves," and "Wave-Transmission over Non-Uniform Cables and Long-Distance Air Lines." * * * * * FRANK BALDWIN JEWETT, A.B., Ph.D. Transmission and Protection Engineer, with American Telephone & Telegraph Co. Author of "Modern Telephone Cable," "Effect of Pressure on Insulation Resistance." * * * * * ARTHUR CROTCH Formerly Lecturer on Telegraphy and Telephony at the Municipal Technical Schools, Norwich, Eng. Author of "Telegraphy and Telephony." * * * * * JAMES ERSKINE-MURRAY, D.Sc. Fellow of the Royal Society of Edinburgh; Member of the Institution of Electrical Engineers. Author of "A Handbook of Wireless Telegraphy." * * * * * A.H. MCMILLAN, A.B., LL.B. Author of "Telephone Law, A Manual on the Organization and Operation of Telephone Companies." * * * * * WILLIAM ESTY, S.B., M.A. Head of Department of Electrical Engineering, Lehigh University. Joint Author of "The Elements of Electrical Engineering." * * * * * GEORGE W. WILDER, Ph.D. Formerly Professor of Telephone Engineering, Armour Institute of Technology. Author of "Telephone Principles and Practice," "Simultaneous Telegraphy and Telephony," etc. * * * * * WILLIAM L. HOOPER, Ph.D. Head of Department of Electrical Engineering, Tufts College. Joint Author of "Electrical Problems for Engineering Students." * * * * * DAVID S. HULFISH Technical Editor, _The Nickelodeon_; Telephone and Motion-Picture Expert; Solicitor of Patents. Author of "How to Read Telephone Circuit Diagrams." * * * * * J.A. FLEMING, M.A., D.Sc. (Lond.), F.R.S. Professor of Electrical Engineering in University College, London; Late Fellow and Scholar of St. John's College, Cambridge; Fellow of University College, London. Author of "The Alternate-Current Transformer," "Radiotelegraphy and Radiotelephony," "Principles of Electric Wave Telegraphy," "Cantor Lectures on Electrical Oscillations and Electric Waves," "Hertzian Wave Wireless Telegraphy," etc. * * * * * F.A.C. PERRINE, A.M., D.Sc. Consulting Engineer: Formerly President, Stanley Electric Manufacturing Company; Formerly Professor of Electrical Engineering, Leland Stanford, Jr. University. Author of "Conductors for Electrical Distribution." * * * * * A. FREDERICK COLLINS Editor, _Collins Wireless Bulletin_. Author of "Wireless Telegraphy, Its History, Theory and Practice," "Manual of Wireless Telegraphy," "Design and Construction of Induction Coils," etc. * * * * * SCHUYLER S. WHEELER, D.Sc. President, Crocker-Wheeler Co.; Past-President, American Institute of Electrical Engineers. Joint Author of "Management of Electrical Machinery." * * * * * CHARLES PROTEUS STEINMETZ Consulting Engineer, with the General Electric Co.; Professor of Electrical Engineering, Union College. Author of "The Theory and Calculation of Alternating-Current Phenomena," "Theoretical Elements of Electrical Engineering", etc. * * * * * GEORGE W. PATTERSON, S.B., Ph.D. Head of Department of Electrical Engineering, University of Michigan. Joint Author of "Electrical Measurements." * * * * * WILLIAM MAVER, JR. Ex-Electrician Baltimore and Ohio Telegraph Company; Member of the American Institute of Electrical Engineers. Author of "American Telegraphy and Encyclopedia of the Telegraph," "Wireless Telegraphy." * * * * * JOHN PRICE JACKSON, M.E. Professor of Electrical Engineering, Pennsylvania State College. Joint Author of "Alternating Currents and Alternating-Current Machinery." * * * * * AUGUSTUS TREADWELL, JR., E.E. Associate Member, American Institute of Electrical Engineers. Author of "The Storage Battery, A Practical Treatise on Secondary Batteries." * * * * * EDWIN J. HOUSTON, Ph.D. Professor of Physics, Franklin Institute, Pennsylvania; Joint Inventor of Thomson-Houston System of Arc Lighting; Electrical Expert and Consulting Engineer. Joint Author of "The Electric Telephone," "The Electric Telegraph," "Alternating Currents," "Arc Lighting," "Electric Heating," "Electric Motors," "Electric Railways," "Incandescent Lighting," etc. * * * * * WILLIAM J. HOPKINS Professor of Physics in the Drexel Institute of Art, Science, and Industry, Philadelphia. Author of "Telephone Lines and their Properties." [Illustration: A TYPICAL SMALL MAGNETO SWITCHBOARD INSTALLATION] [Illustration: A TYPICAL CENTRAL OFFICE FOR RURAL EXCHANGE Line Protectors on Wall at Left.] Foreword The present day development of the "talking wire" has annihilated both time and space, and has enabled men thousands of miles apart to get into almost instant communication. The user of the telephone and the telegraph forgets the tremendousness of the feat in the simplicity of its accomplishment; but the man who has made the feat possible knows that its very simplicity is due to the complexity of the principles and appliances involved; and he realizes his need of a practical, working understanding of each principle and its application. The Cyclopedia of Telephony and Telegraphy presents a comprehensive and authoritative treatment of the whole art of the electrical transmission of intelligence. The communication engineer--if so he may be called--requires a knowledge both of the mechanism of his instruments and of the vagaries of the current that makes them talk. He requires as well a knowledge of plants and buildings, of office equipment, of poles and wires and conduits, of office system and time-saving methods, for the transmission of intelligence is a business as well as an art. And to each of these subjects, and to all others pertinent, the Cyclopedia gives proper space and treatment. The sections on Telephony cover the installation, maintenance, and operation of all standard types of telephone systems; they present without prejudice the respective merits of manual and automatic exchanges; and they give special attention to the prevention and handling of operating "troubles." The sections on Telegraphy cover both commercial service and train dispatching. Practical methods of wireless communication--both by telephone and by telegraph--are thoroughly treated. The drawings, diagrams, and photographs incorporated into the Cyclopedia have been prepared especially for this work; and their instructive value is as great as that of the text itself. They have been used to illustrate and illuminate the text, and not as a medium around which to build the text. Both drawings and diagrams have been simplified so far as is compatible with their correctness, with the result that they tell their own story and always in the same language. The Cyclopedia is a compilation of many of the most valuable Instruction Papers of the American School of Correspondence, and the method adopted in its preparation is that which this School has developed and employed so successfully for many years. This method is not an experiment, but has stood the severest of all tests--that of practical use--which has demonstrated it to be the best yet devised for the education of the busy, practical man. In conclusion, grateful acknowledgment is due to the staff of authors and collaborators, without whose hearty co-operation this work would have been impossible. Table of Contents VOLUME I FUNDAMENTAL PRINCIPLES _By K. B. Miller and S. G. McMeen_[A] Acoustics--Characteristics of Sound--Loudness--Pitch--Vibration of Diaphragms--Timbre--Human Voice--Human Ear--Speech--Magneto Telephones--Loose-Contact Principle--Induction Coils--Simple Telephone Circuit--Capacity--Telephone Currents--Audible and Visible Signals--Telephone Lines--Conductors--Inductance--Insulation SUBSTATION EQUIPMENT _By K. B. Miller and S. G. McMeen_ Transmitters--Variable Resistance--Materials--Single and Multiple Electrodes--Solid-Back Transmitter--Types of Transmitters--Electrodes--Packing--Acousticon Transmitter--Switchboard Transmitter--Receivers--Types of Receivers--Operator's Receiver--Primary Cells--Series and Multiple Connections--Types of Primary Cells--Magneto Signaling Apparatus--Battery Bell--Magneto Bell--Magneto Generator--Armature--Automatic Shunt--Polarized Ringer--Hook Switch--Electromagnets--Impedance, Induction, and Repeating Coils--Non-Inductive Resistance Devices--Differentially-Wound Unit--Condensers--Materials--Current Supply to Transmitters--Local Battery--Common Battery--Diagrams of Common-Battery Systems--Telephone Sets: Magneto, Series and Bridging, Common-Battery PARTY-LINE SYSTEMS _By K. B. Miller and S. G. McMeen_ Non-Selective Party-Line Systems--Series and Bridging--Signal Code--Selective Party-Line Systems: Polarity, Harmonic, Step-by-Step, and Broken-Line--Lock-Out Party-Line Systems: Poole, Step-by-Step, and Broken-Line PROTECTION _By K. B. Miller and S. G. McMeen_ Electrical Hazards--High Potentials--Air-Gap Arrester--Discharge across Gaps--Types of Arrester--Vacuum Arrester--Strong Currents--Fuses--Sneak Currents--Line Protection--Central-Office and Subscribers' Station Protectors--City Exchange Requirements--Electrolysis MANUAL SWITCHBOARDS _By K. B. Miller and S. G. McMeen_ The Telephone Exchange--Subscribers', Trunk, and Toll Lines--Districts--Switchboards--Simple Magneto Switchboard--Operation--Commercial Types of Drops and Jacks--Manual vs. Automatic Restoration--Switchboard Plugs and Cords--Ringing and Listening Keys--Operator's Telephone Equipment--Circuits of Complete Switchboard--Night-Alarm Circuits--Grounded and Metallic Circuit Line--Cord Circuit--Switchboard Assembly REVIEW QUESTIONS INDEX [Footnote A: For professional standing of authors, see list of Authors and Collaborators at front of volume.] [Illustration: OLD BRANCH-TERMINAL MULTIPLE BOARD, PARIS, FRANCE] TELEPHONY INTRODUCTION The telephone was invented in 1875 by Alexander Graham Bell, a resident of the United States, a native of Scotland, and by profession a teacher of deaf mutes in the art of vocal speech. In that year, Professor Bell was engaged in the experimental development of a system of multiplex telegraphy, based on the use of rapidly varying currents. During those experiments, he observed an iron reed to vibrate before an electromagnet as a result of another iron reed vibrating before a distant electromagnet connected to the nearer one by wires. The telephone resulted from this observation with great promptness. In the instrument first made, sound vibrated a membrane diaphragm supporting a bit of iron near an electromagnet; a line joined this simple device of three elements to another like it; a battery in the line magnetized both electromagnet cores; the vibration of the iron in the sending device caused the current in the line to undulate and to vary the magnetism of the receiving device. The diaphragm of the latter was vibrated in consequence of the varying pull upon its bit of iron, and these vibrations reproduced the sound that vibrated the sending diaphragm. The first public use of the electric telephone was at the Centennial Exposition in Philadelphia in 1876. It was there tested by many interested observers, among them Sir William Thomson, later Lord Kelvin, the eminent Scotch authority on matters of electrical communication. It was he who contributed so largely to the success of the early telegraph cable system between England and America. Two of his comments which are characteristic are as follows: To-day I have seen that which yesterday I should have deemed impossible. Soon lovers will whisper their secrets over an electric wire. * * * * * Who can but admire the hardihood of invention which devised such slight means to realize the mathematical conception that if electricity is to convey all the delicacies of sound which distinguish articulate speech, the strength of its current must vary continuously as nearly as may be in simple proportion to the velocity of a particle of the air engaged in constituting the sound. Contrary to usual methods of improving a new art, the earliest improvement of the telephone simplified it. The diaphragms became thin iron disks, instead of membranes carrying iron; the electromagnet cores were made of permanently magnetized steel instead of temporarily magnetized soft iron, and the battery was omitted from the line. The undulatory current in a system of two such telephones joined by a line is _produced_ in the sending telephone by the vibration of the iron diaphragm. The vibration of the diaphragm in the receiving telephone is _produced_ by the undulatory current. Sound is _produced_ by the vibration of the diaphragm of the receiving telephone. Such a telephone is at once the simplest known form of electric generator or motor for alternating currents. It is capable of translating motion into current or current into motion through a wide range of frequencies. It is not known that there is any frequency of alternating current which it is not capable of producing and translating. It can produce and translate currents of greater complexity than any other existing electrical machine. Though possessing these admirable qualities as an electrical machine, the simple electromagnetic telephone had not the ability to transmit speech loudly enough for all practical uses. Transmitters producing stronger telephonic currents were developed soon after the fundamental invention. Some forms of these were invented by Professor Bell himself. Other inventors contributed devices embodying the use of carbon as a resistance to be varied by the motions of the diaphragm. This general form of transmitting telephone has prevailed and at present is the standard type. It is interesting to note that the earliest incandescent lamps, as invented by Mr. Edison, had a resistance material composed of carbon, and that such a lamp retained its position as the most efficient small electric illuminant until the recent introduction of metal filament lamps. It is possible that some form of metal may be introduced as the resistance medium for telephone transmitters, and that such a change as has taken place in incandescent lamps may increase the efficiency of telephone transmitting devices. At the time of the invention of the telephone, there were in existence two distinct types of telegraph, working in regular commercial service. In the more general type, many telegraph stations were connected to a line and whatever was telegraphed between two stations could be read by all the stations of that line. In the other and less general type, many lines, each having a single telegraph station, were centered in an office or "exchange," and at the desire of a user his line could be connected to another and later disconnected from it. Both of these types of telegraph service were imitated at once in telephone practice. Lines carrying many telephones each, were established with great rapidity. Telephones actually displaced telegraphic apparatus in the exchange method of working in America. The fundamental principle on which telegraph or telephone exchanges operate, being that of placing any line in communication with any other in the system, gave to each line an ultimate scope so great as to make this form of communication more popular than any arrangement of telephones on a single line. Beginning in 1877, telephone exchanges were developed with great rapidity in all of the larger communities of the United States. Telegraph switching devices were utilized at the outset or were modified in such minor particulars as were necessary to fit them to the new task. In its simplest form, a telephone system is, of course, a single line permanently joining two telephones. In its next simplest form, it is a line permanently joining more than two telephones. In its most useful form, it is a line joining a telephone to some means of connecting it at will to another. A telephone exchange central office contains means for connecting lines at will in that useful way. The least complicated machine for that purpose is a switchboard to be operated by hand, having some way of letting the operator know that a connection is wished and a way of making it. The customary way of connecting the lines always has been by means of flexible conductors fitted with plugs to be inserted in sockets. If the switchboard be small enough so that all the lines are within arm's reach of the operator, the whole process is individual, and may be said to be at its best and simplest. There are but few communities, however, in which the number of lines to be served and calls to be answered is small enough so that the entire traffic of the exchange can be handled by a single person. An obvious way, therefore, is to provide as many operators in a central office as may be required by the number of calls to be answered, and to terminate before each of the operators enough of the lines to bring enough work to keep that operator economically occupied. This presents the additional problem, how to connect a line terminating before one operator to a line normally terminating before another operator. The obvious answer is to provide lines from each operator's place of work to each other operator's place, connecting a calling line to some one of these lines which are local within the central office, and, in turn, connecting that chosen local line to the line which is called. Such lines between operators have come to be known as _trunk lines_, because of the obvious analogy to trunk lines of railways between common centers, and such a system of telephone lines may be called a _trunking system_. Very good service has been given and can be given by such an arrangement of local trunks, but the growth in lines and in traffic has developed in most instances certain weaknesses which make it advisable to find speedier, more accurate, and more reliable means. For the serving of a large traffic from a large number of lines, as is required in practically every city of the world, a very great contribution to the practical art was made by the development of the multiple switchboard. Such a switchboard is merely such a device as has been described for the simpler cases, with the further refinement that within reach of each operator in the central office appears _every line which enters that office_, and this without regard to what point in the switchboard the lines may terminate for the _answering_ of calls. In other words, while each operator answers a certain subordinate group of the total number of lines, each operator may reach, for calling purposes, every line which enters that office. It is probable that the invention and development of the multiple switchboard was the first great impetus toward the wide-spread use of telephone service. Coincident with the development of the multiple switchboard for manually operated, central-office mechanisms was the beginning of the development of automatic apparatus under the control of the calling subscriber for finding and connecting with a called line. It is interesting to note the general trend of the early development of automatic apparatus in comparison with the development, to that time, of manual telephone apparatus. While the manual apparatus on the one hand attempted to meet its problem by providing local trunks between the various operators of a central office, and failing of success in that, finally developed a means which placed all the lines of a central office within connecting reach of each operator, automatic telephony, beginning at that point, failed of success in attempting to bring each line in the central office within connecting reach of each connecting mechanism. In other terms, the first automatic switching equipment consisted of a machine for each line, which machine was so organized as to be able to find and connect its calling line with any called line of the entire central-office group. It may be said that an attempt to develop this plan was the fundamental reason for the repeated failure of automatic apparatus to solve the problem it attacked. All that the earlier automatic system did was to prove more or less successfully that automatic apparatus had a right to exist, and that to demand of the subscriber that he manipulate from his station a distant machine to make the connection without human aid was not fallacious. When it had been recognized that the entire multiple switchboard idea could not be carried into automatic telephony with success, the first dawn of hope in that art may be said to have come. Success in automatic telephony did come by the re-adoption of the trunking method. As adopted for automatic telephony, the method contemplates that the calling line shall be extended, link by link, until it finds itself lengthened and directed so as to be able to seize the called line in a very much smaller multiple than the total group of one office of the exchange. A similar curious reversion has taken place in the development of telephone lines. The earliest telephone lines were merely telegraph lines equipped with telephone instruments, and the earliest telegraph lines were planned by Professor Morse to be insulated wires laid in the earth. A lack of skill in preparing the wires for putting in the earth caused these early underground lines to be failures. At the urging of one of his associates, Professor Morse consented to place his earliest telegraph lines on poles in the air. Each such line originally consisted of two wires, one for the going and one for the returning current, as was then considered the action. Upon its being discovered that a single wire, using the earth as a return, would serve as a satisfactory telegraph line, such practice became universal. Upon the arrival of the telephone, all lines obviously were built in the same way, and until force of newer circumstances compelled it, the present metallic circuit without an earth connection did not come into general use. The extraordinary growth of the number of telephone lines in a community and the development of other methods of electrical utilization, as well as the growth in the knowledge of telephony itself, ultimately forced the wires underground again. At the same time and for the same causes, a telephone line became one of two wires, so that it becomes again the counterpart of the earliest telegraph line of Professor Morse. Another curious and interesting example of this reversion to type exists in the simple telephone receiver. An early improvement in telephone receivers after Professor Bell's original invention was to provide the necessary magnetism of the receiver core by making it of steel and permanently magnetizing it, whereas Professor Bell's instrument provided its magnetism by means of direct current flowing in the line. In later days the telephone receiver has returned almost to the original form in which Professor Bell produced it and this change has simplified other elements of telephone-exchange apparatus in a very interesting and gratifying way. By reason of improvements in methods of line construction and apparatus arrangement, the radius of communication steadily has increased. Commercial speech now is possible between points several thousand miles apart, and there is no theoretical reason why communication might not be established between any two points on the earth's surface. The practical reasons of demand and cost may prevent so great an accomplishment as talking half around the earth. So far as science is concerned there would seem to be no reason why this might not be done today, by the careful application of what already is known. In the United States, telephone service from its beginning has been supplied to users by private enterprise. In other countries, it is supplied by means of governmentally-owned equipment. In general, it may be said that the adequacy and the amount, as well as the quality of telephone service, is best in countries where the service is provided by private enterprise. Telephone systems in the United States were under the control of the Bell Telephone Company from the invention of the device in 1876 until 1893. The fundamental telephone patent expired in 1893. This opened the telephone art to the general public, because it no longer was necessary to secure telephones solely from the patent-holding company nor to pay royalty for the right to use them, if secured at all. Manufacturers of electrical apparatus generally then began to make and sell telephones and telephone apparatus, and operating companies, also independent of the Bell organization, began to install and use telephones. At the end of seventeen years of patent monopoly in the United States, there were in operation a little over 250,000 telephones. In the seventeen years since the expiration of the fundamental patent, independent telephone companies throughout the United States have installed and now have in daily successful use over 3,911,400 telephones. In other words, since its first beginnings, independent telephony has brought into continuous daily use nearly sixteen times as many telephones as were brought into use in the equal time of the complete monopoly of the Bell organization. At the beginning of 1910, there were in service by the Bell organization about 3,633,900 telephones. These with the 3,911,400 independent telephones, make a total of 7,545,300, or about one-twelfth as many telephones as there are inhabitants of the United States. The influence of this development upon the lives of the people has been profound. Whether the influence has been wholly for good may not be so conclusively apparent. Lord Bacon has declared that, excepting only the alphabet and the art of printing, those inventions abridging distance are of the greatest service to mankind. If this be true, it may be said that the invention of telephony deserves high place among the civilizing influences. There is no industrial art in which the advancement of the times has been followed more closely by practical application than in telephony. Commercial speech by telephone is possible by means of currents which so far are practically unmeasurable. In other words, it is possible to speak clearly and satisfactorily over a line by means of currents which cannot be read, with certainty as to their amount, by any electrical measuring device so far known. In this regard, telephony is less well fortified than are any of the arts utilizing electrical power in larger quantities. The real wonder is that with so little knowledge of what takes place, particularly as to amount, those working in the art have been able to do as well as they have. When an exact knowledge of quantity is easily obtainable, very striking advances may be looked for. The student of these phases of physical science and industrial art will do well to combine three processes: study of the words of others; personal experimentation; and digestive thought. The last mentioned is the process of profoundest value. On it finally depends mastery. It is not of so much importance how soon the concept shall finally be gained as _that it is gained_. A statement by another may seem lifeless and inert and the meaning of an observation may be obscure. Digestive thought is the only assimilative process. The whole art of telephony hangs on taking thought of things. Judge R.F. Taylor of Indiana said of Professor Bell, "It has been said that no man by taking thought may add a cubit to his stature, yet here is a man who, by taking thought, has added not cubits but miles to the lengths of men's tongues and ears." In observations of many students, it is found that the notion of each must pass through a certain period of incubation before his private and personal knowledge of Ohm's law is hatched. Once hatched, however, it is his. By just such a process must come each principal addition to his stock of concepts. The periods may vary and practice in the uses of the mind may train it in alertness in its work. If time is required, time should be given, the object always being to keep thinking or re-reading or re-trying until the thought is wholly encompassed and possessed. CHAPTER I ACOUSTICS Telephony is the art of reproducing at a distant point, usually by the agency of electricity, sounds produced at a sending point. In this art the elements of two general divisions of physical science are concerned, sound and electricity. Sound is the effect of vibrations of matter upon the ear. The vibrations may be those of air or other matter. Various forms of matter transmit sound vibrations in varying degrees, at different specific speeds, and with different effects upon the vibrations. Any form of matter may serve as a transmitting medium for sound vibrations. Sound itself is an effect of sound vibrations upon the ear. Propagation of Sound. Since human beings communicate with each other by means of speech and hearing through the air, it is with air that the acoustics of telephony principally is concerned. In air, sound vibrations consist of successive condensations and rarefactions tending to proceed outwardly from the source in all directions. The source is the center of a sphere of sound vibrations. Whatever may be the nature of the sounds or of the medium transmitting them, they consist of waves emitted by the source and observed by the ear. A sound wave is one complete condensation and rarefaction of the transmitting medium. It is produced by one complete vibration of the sound-producing thing. Sound waves in air travel at a rate of about 1,090 feet per second. The rate of propagation of sound waves in other materials varies with the density of the material. For example, the speed of transmission is much greater in water than in air, and is much less in highly rarefied air than in air at ordinary density. The propagation of sound waves in a vacuum may be said not to take place at all. Characteristics of Sound. Three qualities distinguish sound: loudness, pitch, and timbre. _Loudness._ Loudness depends upon the violence of the effect upon the ear; sounds may be alike in their other qualities and differ in loudness, the louder sounds being produced by the stronger vibrations of the air or other medium at the ear. Other things being equal, the louder sound is produced by the source radiating the greater energy and so producing the greater _degree_ of condensation and rarefaction of the medium. _Pitch._ Pitch depends upon the frequency at which the sound waves strike the ear. Pitches are referred to as _high_ or _low_ as the frequency of waves reaching the ear are greater or fewer. Familiar low pitches are the left-hand strings of a piano; the larger ones of stringed instruments generally; bass voices; and large bells. Familiar high pitches are right-hand piano strings; smaller ones of other stringed instruments; soprano voices; small bells; and the voices of most birds and insects. Doppler's Principle:--As pitch depends upon the frequency at which sound waves strike the ear, an object may emit sound waves at a constant frequency, yet may produce different pitches in ears differently situated. Such a case is not usual, but an example of it will serve a useful purpose in fixing certain facts as to pitch. Conceive two railroad trains to pass each other, running in opposite directions, the engine bells of both trains ringing. Passengers on each train will hear the bell of the other, first as a _rising_ pitch, then as a _falling_ one. Passengers on each train will hear the bell of their own train at a _constant_ pitch. The difference in the observations in such a case is due to relative positions between the ear and the source of the sound. As to the bell of their own train, the passengers are a fixed distance from it, whether the train moves or stands; as to the bell of the other train, the passengers first rapidly approach it, then pass it, then recede from it. The distances at which it is heard vary as the secants of a circle, the radius in this case being a length which is the closest approach of the ear to the bell. If the bell have a constant intrinsic fundamental pitch of 200 waves per second (a wave-length of about 5.5 feet), it first will be heard at a pitch of about 200 waves per second. But this pitch rises rapidly, as if the bell were changing its own pitch, which bells do not do. The rising pitch is heard because the ear is rushing down the wave-train, every instant nearer to the source. At a speed of 45 miles an hour, the pitch rises rapidly, about 12 vibrations per second. If the _rate of approach_ between the ear and the bell were constant, the pitch of the bell would be heard at 212 waves per second. But suddenly the ear passes the bell, hears the pitch stop rising and begin to fall; and the tone drops 12 waves per second as it had risen. Such a circumflex is an excellent example of the bearing of wavelengths and frequencies upon pitch. Vibration of Diaphragms:--Sound waves in air have the power to move other diaphragms than that of the ear. Sound waves constantly vibrate such diaphragms as panes of windows and the walls of houses. The recording diaphragm of a phonograph is a window pane bearing a stylus adapted to engrave a groove in a record blank. In the cylinder form of record, the groove varies in depth with the vibrations of the diaphragm. In the disk type of phonograph, the groove varies sidewise from its normal true spiral. If the disk record be dusted with talcum powder, wiped, and examined with a magnifying glass, the waving spiral line may be seen. Its variations are the result of the blows struck upon the diaphragm by a train of sound waves. In reproducing a phonograph record, increasing the speed of the record rotation causes the pitch to rise, because the blows upon the air are increased in frequency and the wave-lengths shortened. A transitory decrease in speed in recording will cause a transitory rise in pitch when that record is reproduced at uniform speed. _Timbre._ Character of sound denotes that difference of effect produced upon the ear by sounds otherwise alike in pitch and loudness. This characteristic is called timbre. It is extraordinarily useful in human affairs, human voices being distinguished from each other by it, and a great part of the joy of music lying in it. A bell, a stretched string, a reed, or other sound-producing body, emits a certain lowest possible tone when vibrated. This is called its _fundamental tone_. The pitch, loudness, and timbre of this tone depend upon various controlling causes. Usually this fundamental tone is accompanied by a number of others of higher pitch, blending with it to form the general tone of that object. These higher tones are called _harmonics_. The Germans call them _overtones_. They are always of a frequency which is some multiple of the fundamental frequency. That is, the rate of vibration of a harmonic is 2, 3, 4, 5, or some other integral number, times as great as the fundamental itself. A tone having no harmonics is rare in nature and is not an attractive one. The tones of the human voice are rich in harmonics. In any tone having a fundamental and harmonics (multiples), the wave-train consists of a complex series of condensations and rarefactions of the air or other transmitting medium. In the case of mere noises the train of vibrations is irregular and follows no definite order. This is the difference between vowel sounds and other musical tones on the one hand and all unmusical sounds (or noises) on the other. Human Voice. Human beings communicate with each other in various ways. The chief method is by speech. Voice is sound vibration produced by the vocal cords, these being two ligaments in the larynx. The vocal cords in man are actuated by the air from the lungs. The size and tension of the vocal cords and the volume and the velocity of the air from the lungs control the tones of the voice. The more tightly the vocal cords be drawn, other things being equal, the higher will be the pitch of the sound; that is, the higher the frequency of vibration produced by the voice. The pitches of the human voice lie, in general, between the frequencies of 87 and 768 per second. These are the extremes of pitch, and it is not to be understood that any such range of pitch is utilized in ordinary speech. An average man speaks mostly between the fundamental frequencies of 85 and 160 per second. Many female speaking voices use fundamental frequencies between 150 and 320 vibrations per second. It is obvious from what has been said that in all cases these speaking fundamentals are accompanied by their multiples, giving complexity to the resulting wave-trains and character to the speaking voice. Speech-sounds result from shocks given to the air by the organs of speech; these organs are principally the mouth cavity, the tongue, and the teeth. The vocal cords are _voice-organs_; that is, man only truly speaks, yet the lower animals have voice. Speech may be whispered, using no voice. Note the distinction between speech and voice, and the organs of both. The speech of adults has a mean pitch lower than that of children; of adult males, lower than that of females. There is no close analogue for the voice-organ in artificial mechanism, but the use of the lips in playing a bugle, trumpet, cornet, or trombone is a fairly close one. Here the lips, in contact with each other, are stretched across one end of a tube (the mouthpiece) while the air is blown between the lips by the lungs. A musical tone results; if the instrument be a bugle or a trumpet of fixed tube length, the pitch will be some one of several certain tones, depending on the tension on the lips. The loudness depends on the force of the blast of air; the character depends largely on the bugle. Human Ear. The human ear, the organ of hearing in man, is a complex mechanism of three general parts, relative to sound waves: a wave-collecting part; a wave-observing part, and a wave-interpreting part. The outer ear collects and reflects the waves inwardly to beat upon the tympanum, or ear drum, a membrane diaphragm. The uses of the rolls or convolutions of the outer ear are not conclusively known, but it is observed that when they are filled up evenly with a wax or its equivalent, the sense of direction of sound is impaired, and usually of loudness also. The diaphragm of the ear vibrates when struck by sound waves, as does any other diaphragm. By means of bone and nerve mechanism, the vibration of the diaphragm finally is made known to the brain and is interpretable therein. The human ear can appreciate and interpret sound waves at frequencies from 32 to about 32,000 vibrations per second. Below the lesser-number, the tendency is to appreciate the separate vibrations as separate sounds. Above the higher number, the vibrations are inaudible to the human ear. The most acute perception of sound differences lies at about 3,000 vibrations per second. It may be that the range of hearing of organisms other than man lies far above the range with which human beings are familiar. Some trained musicians are able to discriminate between two sounds as differing one from the other when the difference in frequency is less than one-thousandth of either number. Other ears are unable to detect a difference in two sounds when they differ by as much as one full step of the chromatic scale. Whatever faculty an individual may possess as to tone discrimination, it can be improved by training and practice. CHAPTER II ELECTRICAL REPRODUCTION OF SPEECH The art of telephony in its present form has for its problem so to relate two diaphragms and an electrical system that one diaphragm will respond to all the fundamental and harmonic vibrations beating upon it and cause the other to vibrate in exact consonance, producing just such vibrations, which beat upon an ear. The art does not do all this today; it falls short of it in every phase. Many of the harmonics are lost in one or another stage of the process; new harmonics are inserted by the operations of the system itself and much of the volume originally available fails to reappear. The art, however, has been able to change commercial and social affairs in a profound degree. Conversion from Sound Waves to Vibration of Diaphragm. However produced, by the voice or otherwise, sounds to be transmitted by telephone consist of vibrations of the air. These vibrations, upon reaching a diaphragm, cause it to move. The greatest amplitude of motion of a diaphragm is, or is wished to be, at its center, and its edge ordinarily is fixed. The diaphragm thus serves as a translating device, changing the energy carried by the molecules of the air into localized oscillations of the matter of the diaphragm. The waves of sound in the air advance; the vibrations of the molecules are localized. The agency of the air as a medium for sound transmission should be understood to be one in which its general volume has no need to move from place to place. What occurs is that the vibrations of the sound-producer cause alternate condensations and rarefactions of the air. Each molecule of the air concerned merely oscillates through a small amplitude, producing, by joint action, shells of waves, each traveling outward from the sound-producing center like rapidly growing coverings of a ball. Conversion from Vibration to Voice Currents. Fig. 1 illustrates a simple machine adapted to translate motion of a diaphragm into an alternating electrical current. The device is merely one form of magneto telephone chosen to illustrate the point of immediate conversion. _1_ is a diaphragm adapted to vibrate in response to the sounds reaching it. _2_ is a permanent magnet and _3_ is its armature. The armature is in contact with one pole of the permanent magnet and nearly in contact with the other. The effort of the armature to touch the pole it nearly touches places the diaphragm under tension. The free arm of the magnet is surrounded by a coil _4_, whose ends extend to form the line. [Illustration: Fig. 1. Type of Magneto Telephone] When sound vibrates the diaphragm, it vibrates the armature also, increasing and decreasing the distance from the free pole of the magnet. The lines of force threading the coil _4_ are varied as the gap between the magnet and the armature is varied. The result of varying the lines of force through the turns of the coil is to produce an electromotive force in them, and if a closed path is provided by the line, a current will flow. This current is an alternating one having a frequency the same as the sound causing it. As in speech the frequencies vary constantly, many pitches constituting even a single spoken word, so the alternating voice currents are of great varying complexity, and every fundamental frequency has its harmonics superposed. Conversion from Voice Currents to Vibration. The best knowledge of the action of such a telephone as is shown in Fig. 1 leads to the conclusion that a half-cycle of alternating current is produced by an inward stroke of the diaphragm and a second half-cycle of alternating current by the succeeding outward stroke, these half-cycles flowing in opposite directions. Assume one complete cycle of current to pass through the line and also through another such device as in Fig. 1 and that the first half-cycle is of such direction as to increase the permanent magnetism of the core. The effort of this increase is to narrow the gap between the armature and pole piece. The diaphragm will throb inward during the half-cycle of current. The succeeding half-cycle being of opposite direction will tend to oppose the magnetism of the core. In practice, the flow of opposing current never would be great enough wholly to nullify and reverse the magnetism of the core, so that the opposition results in a mere decrease, causing the armature's gap to increase and the diaphragm to respond by an outward blow. Complete Cycle of Conversion. The cycle of actions thus is complete; one complete sound-wave in air has produced a cycle of motion in a diaphragm, a cycle of current in a line, a cycle of magnetic change in a core, a cycle of motion in another diaphragm, and a resulting wave of sound. It is to be observed that the chain of operation involves the expenditure of energy only by the speaker, the only function of any of the parts being that of _translating_ this energy from one form to another. In every stage of these translations, there are losses; the devising of means of limiting these losses as greatly as possible is a problem of telephone engineering. [Illustration: Fig. 2. Magneto Telephones and Line] Magneto Telephones. The device in Fig. 1 is a practical magneto receiver and transmitter. It is chosen as best picturing the idea to be proposed. Fig. 2 illustrates a pair of magneto telephones of the early Bell type; _1-1_ are diaphragms; _2-2_ are permanent magnets with a free end of each brought as near as possible, without touching, to the diaphragm. Each magnet bears on its end nearest the diaphragm a winding of fine wire, the two ends of each of these windings being joined by means of a two-wire line. All that has been said concerning Fig. 1 is true also of the electrical and magnetic actions of the devices of Fig. 2. In the latter, the flux which threads the fine wire winding is disturbed by motions of the transmitting diaphragm. This disturbance of the flux creates electromotive forces in those windings. Similarly, a variation of the electromotive forces in the windings varies the pull of the permanent magnet of the receiving instrument upon its diaphragm. [Illustration: No. 10 SERIES MULTIPLE SWITCHBOARD _Monarch Telephone Mfg. Co._] [Illustration: Fig. 3. Magneto Telephones without Permanent Magnets] Fig. 3 illustrates a similar arrangement, but it is to be understood that the cores about which the windings are carried in this case are of soft iron and not of hard magnetized steel. The necessary magnetism which constantly enables the cores to exert a pull upon the diaphragm is provided by the battery which is inserted serially in the line. Such an arrangement in action differs in no particular from that of Fig. 2, for the reason that it matters not at all whether the magnetism of the core be produced by electromagnetic or by permanently magnetic conditions. The arrangement of Fig. 3 is a fundamental counterpart of the original telephone of Professor Bell, and it is of particular interest in the present stage of the art for the reason that a tendency lately is shown to revert to the early type, abandoning the use of the permanent magnet. The modifications which have been made in the original magneto telephone, practically as shown in Fig. 2, have been many. Thirty-five years' experimentation upon and daily use of the instrument has resulted in its refinement to a point where it is a most successful receiver and a most unsuccessful transmitter. Its use for the latter purpose may be said to be nothing. As a receiver, it is not only wholly satisfactory for commercial use in its regular function, but it is, in addition, one of the most sensitive electrical detecting devices known to the art. Loose Contact Principle. Early experimenters upon Bell's device, all using in their first work the arrangement utilizing current from a battery in series with the line, noticed that sound was given out by disturbing loose contacts in the line circuit. This observation led to the arrangement of circuits in such a way that some imperfect contacts could be shaken by means of the diaphragm, and the resistance of the line circuit varied in this manner. An early and interesting form of such imperfect contact transmitter device consisted merely of metal conductors laid loosely in contact. A simple example is that of three wire nails, the third lying across the other two, the two loose contacts thus formed being arranged in series with a battery, the line, and the receiving instrument. Such a device when slightly jarred, by the voice or other means, causes abrupt variation in the resistance of the line, and will transmit speech. Early Conceptions. The conception of the possibility and desirability of transmitting speech by electricity may have occurred to many, long prior to its accomplishment. It is certain that one person, at least, had a clear idea of the general problem. In 1854, Charles Bourseul, a Frenchman, wrote: "I have asked myself, for example, if the spoken word itself could not be transmitted by electricity; in a word, if what was spoken in Vienna might not be heard in Paris? The thing is practicable in this way: [Illustration: Fig. 4. Reis Transmitter] "Suppose that a man speaks near a movable disk sufficiently flexible to lose none of the vibrations of the voice; that this disk _alternately makes and breaks_ the connection from a battery; you may have at a distance another disk which will simultaneously execute the same vibrations." The idea so expressed is weak in only one particular. This particular is shown by the words italicized by ourselves. It is impossible to transmit a complex series of waves by any simple series of makes and breaks. Philipp Reis, a German, devised the arrangement shown in Fig. 4 for the transmission of sound, letting the make and break of the contact between the diaphragm _1_ and the point _2_ interrupt the line circuit. His receiver took several forms, all electromagnetic. His success was limited to the transmission of musical sounds, and it is not believed that articulate speech ever was transmitted by such an arrangement. It must be remembered that the art of telegraphy, particularly in America, was well established long before the invention of the telephone, and that an arrangement of keys, relays, and a battery, as shown in Fig. 5, was well known to a great many persons. Attaching the armatures of the relays of such a line to diaphragms, as in Fig. 6, at any time after 1838, would have produced the telephone. "The hardihood of invention" to conceive such a change was the quality required. [Illustration: Fig. 5. Typical Telegraph Line] Limitations of Magneto Transmitter. For reasons not finally established, the ability of the magneto telephone to produce large currents from large sounds is not equal to its ability to produce large sounds from large currents. As a receiving device, it is unexcelled, and but slight improvement has been made since its first invention. It is inadequate as a transmitter, and as early as 1876, Professor Bell exhibited other means than electromagnetic action for producing the varying currents as a consequence of diaphragm motion. Much other inventive effort was addressed to this problem, the aim of all being to send out more robust voice currents. [Illustration: Fig. 6. Telegraph Equipment Converted into Telephone Equipment] Other Methods of Producing Voice Currents. Some of these means are the variation of resistance in the path of direct current, variation in the pressure of the source of that current, and variation in the electrostatic capacity of some part of the circuit. _Electrostatic Telephone._ The latter method is principally that of Dolbear and Edison. Dolbear's thought is illustrated in Fig. 7. Two conducting plates are brought close together. One is free to vibrate as a diaphragm, while the other is fixed. The element _1_ in Fig. 7 is merely a stud to hold rigid the plate it bears against. Each of two instruments connected by a line contains such a pair of plates, and a battery in the line keeps them charged to its potential. The two diaphragms of each instrument are kept drawn towards each other because their unlike charges attract each other. The vibration of one of the diaphragms changes the potential of the other pair; the degree of attraction thus is varied, so that vibration of the diaphragm and sound waves result. Examples of this method of telephone transmission are more familiar to later practice in the form of condenser receivers. A condenser, in usual present practice, being a pair of closely adjacent conductors of considerable surface insulated from each other, a rapidly varying current actually may move one or both of the conductors. Ordinarily these are of thin sheet metal (foil) interleaved with an insulating material, such as paper or mica. Voice currents can vibrate the metal sheets in a degree to cause the condenser to speak. These condenser methods of telephony have not become commercial. [Illustration: Fig. 7. Electrostatic Telephone] _Variation of Electrical Pressure._ Variation of the pressure of the source is a conceivable way of transmitting speech. To utilize it, would require that the vibrations of the diaphragm cause the electromotive force of a battery or machine to vary in harmony with the sound waves. So far as we are informed this method never has come into practical use. _Variation of Resistance._ Variation of resistance proportional to the vibrations of the diaphragm is the method which has produced the present prevailing form of transmission. Professor Bell's Centennial exhibit contained a water-resistance transmitter. Dr. Elisha Gray also devised one. In both, the diaphragm acted to increase and diminish the distance between two conductors immersed in water, lowering and raising the resistance of the line. It later was discovered by Edison that carbon possesses a peculiarly great property of varying its resistance under pressure. Professor David E. Hughes discovered that two conducting bodies, preferably of rather poor conductivity, when laid together so as to form a _loose contact_ between them, possessed, in remarkable degree, the ability to vary the resistance of the path through them when subject to such vibrations as would alter the _intimacy of contact_. He thus discovered and formulated the principles of _loose contact_ upon which the operation of all modern transmitters rests. Hughes' device was named by him a "microphone," indicating a magnification of sound or an ability to respond to and make audible minute sounds. It is shown in Fig. 8. Firmly attached to a board are two carbon blocks, shown in section in the figure. A rod of carbon with cone-shaped ends is supported loosely between the two blocks, conical depressions in the blocks receiving the ends of the rod. A battery and magneto receiver are connected in series with the device. Under certain conditions of contact, the arrangement is extraordinarily sensitive to small sounds and approaches an ability indicated by its name. Its practical usefulness has been not as a serviceable speech transmitter, but as a stimulus to the devising of transmitters using carbon in other ways. Variation of the resistance of metal conductors and of contact between metals has served to transmit voice currents, but no material approaches carbon in this property. [Illustration: Fig. 8. Hughes' Microphone] Carbon. _Adaptability._ The application of carbon to use in transmitters has taken many forms. They may be classified as those having a single contact and those having a plurality of contacts; in all cases, the _intimacy of contact_ is varied by the diaphragm excursions. An example of the single-contact type is the Blake transmitter, long familiar in America. An example of the multiple-contact type is the loose-carbon type universal now. Other types popular at other times and in particular places use solid rods or blocks of carbon having many points of contact, though not in a powdered or granular form. Fig. 9 shows an example of each of the general forms of transmitters. The use of granular carbon as a transmitter material has extended greatly the radius of speech, and has been a principal contributing cause for the great spread of the telephone industry. [Illustration: Fig. 9. General Types of Transmitters] _Superiority._ The superiority of carbon over other resistance-varying materials for transmitters is well recognized, but the reason for it is not well known. Various theories have been proposed to explain why, for example, the resistance of a mass of carbon granules varies with the vibrations or compressions to which they are subjected. Four principal theories respectively allege: First, that change in pressure actually changes the specific resistance of carbon. Second, that upon the surface of carbon bodies exists some gas in some form of attachment or combination, variations of pressure causing variations of resistance merely by reducing the thickness of this intervening gas. Third, that the change of resistance is caused by variations in the length of electrical arcs between the particles. Fourth, that change of pressure changes the area of contact, as is true of solids generally. One may take his choice. A solid carbon block or rod is not found to decrease its resistance by being subjected to pressure. The gas theory lacks experimental proof also. The existence of arcs between the granules never has been seen or otherwise observed under normal working conditions of a transmitter; when arcs surely are experimentally established between the granules the usefulness of the transmitter ceases. The final theory, that change of pressure changes area of surface contact, does not explain why other conductors than carbon are not good materials for transmitters. This, it may be noticed, is just what the theories set out to make clear. There are many who feel that more experimental data is required before a conclusive and satisfactory theory can be set up. There is need of one, for a proper theory often points the way for effective advance in practice. Carbon and magneto transmitters differ wholly in their methods of action. The magneto transmitter _produces_ current; the carbon transmitter _controls_ current. The former is an alternating-current generator; the latter is a rheostat. The magneto transmitter produces alternating current without input of any electricity at all; the carbon transmitter merely controls a direct current, supplied by an external source, and varies its amount without changing its direction. The carbon transmitter, however, may be associated with other devices in a circuit in such a way as to _transform_ direct currents into alternating ones, or it may be used merely to change constant direct currents into _undulating_ ones, which _never_ reverse direction, as alternating currents _always_ do. These distinctions are important. [Illustration: Fig. 10. Battery in Line Circuit] _Limitations._ A carbon transmitter being merely a resistance-varying device, its usefulness depends on how much its resistance can vary in response to motions of air molecules. A granular-carbon transmitter may vary between resistances of 5 to 50 ohms while transmitting a particular tone, having the lower resistance when its diaphragm is driven inward. Conceive this transmitter to be in a line as shown in Fig. 10, the line, distant receiver, and battery together having a resistance of 1,000 ohms. The minimum resistance then is 1,005 ohms and the maximum 1,050 ohms. The variation is limited to about 4.5 per cent. The greater the resistance of the line and other elements than the transmitter, the less relative change the transmitter can produce, and the less loudly the distant receiver can speak. [Illustration: Fig 11. Battery in Local Circuit] Induction Coil. Mr. Edison realized this limitation to the use of the carbon transmitter direct in the line, and contributed the means of removing it. His method is to introduce an induction coil between the line and the transmitter, its function being to translate the variation of the direct current controlled by the transmitter into true alternating currents. An induction coil is merely a transformer, and for the use under discussion consists of two insulated wires wound around an iron core. Change in the current carried by one of the windings _produces_ a current in the other. If direct current be flowing in one of the windings, and remains constant, no current whatever is produced in the other. It is important to note that it is change, and change only, which produces that alternating current. Fig. 11 shows an induction coil related to a carbon transmitter, a battery, and a receiver. Fig. 12 shows exactly the same arrangement, using conventional signs. The winding of the induction coil which is in series with the transmitter and the battery is called the primary winding; the other is called the secondary winding. In the arrangement of Figs. 11 and 12 the battery has no metallic connection with the line, so that it is called a _local battery_. The circuit containing the battery, transmitter, and primary winding of the induction coil is called the _local circuit_. Let us observe what is the advantage of this arrangement over the case of Fig. 10. Using the same values of resistance in the transmitter and line, assume the local circuit apart from the transmitter to have a fixed resistance of 5 ohms. The limits of variations in the local circuit, therefore, are 10 and 55 ohms, thus making the maximum 5.5 times the minimum, or an increase of 450 per cent as against 4.5 per cent in the case of Fig. 10. The changes, therefore, are 100 times as great. [Illustration: Fig. 12. Conventional Diagram of Talking Circuit] The relation between the windings of the induction coil in this practice are such that the secondary winding contains many more turns than the primary winding. Changes in the circuit of the primary winding produce potentials in the secondary winding correspondingly higher than the potentials producing them. These secondary potentials depend upon the _ratio_ of turns in the two windings and therefore, within close limits, may be chosen as wished. High potentials in the secondary winding are admirably adapted to transmit currents in a high-resistance line, for exactly the same reason that long-distance power transmission meets with but one-quarter of one kind of loss when the sending potential is doubled, one-hundredth of that loss when it is raised tenfold, and similarly. The induction coil, therefore, serves the double purpose of a step-up transformer to limit line losses and a device for vastly increasing the range of change in the transmitter circuit. Fig. 13 is offered to remind the student of the action of an induction coil or transformer in whose primary circuit a direct current is increased and decreased. An increase of current in the local winding produces an impulse of _opposite_ direction in the turns of the secondary winding; a decrease of current in the local winding produces an impulse of _the same_ direction in the turns of the secondary winding. The key of Fig. 13 being closed, current flows upward in the primary winding as drawn in the figure, inducing a downward impulse of current in the secondary winding and its circuit as noted at the right of the figure. On the key being opened, current ceases in the primary circuit, inducing an upward impulse of current in the secondary winding and circuit as shown. During other than instants of opening and closing (changing) the local circuit, no current whatever flows in the secondary circuit. [Illustration: Fig. 13. Induction-Coil Action] It is by these means that telephone transmitters draw direct current from primary batteries and send high-potential alternating currents over lines; the same process produces what in Therapeutics are called "Faradic currents," and enables also a simple vibrating contact-maker to produce alternating currents for operating polarized ringers of telephone sets. Detrimental Effects of Capacity. Electrostatic capacity plays an important part in the transmission of speech. Its presence between the wires of a line and between them and the earth causes one of the losses from which long-distance telephony suffers. Its presence in condensers assists in the solution of many circuit and apparatus problems. A condenser is a device composed of two or more conductors insulated from each other by a medium called the _dielectric_. A pair of metal plates separated by glass, a pair of wires separated by air, or a pair of sheets of foil separated by paper or mica may constitute a condenser. The use of condensers as pieces of apparatus and the problems presented by electrostatic capacity in lines are discussed in other chapters. Measurements of Telephone Currents. It has been recognized in all branches of engineering that a definite advance is possible only when quantitative data exists. The lack of reliable means of measuring telephone currents has been a principal cause of the difficulty in solving many of its problems. It is only in very recent times that accurate and reliable means have been worked out for measuring the small currents which flow in telephone lines. These ways are of two general kinds: by thermal and by electromagnetic means. _Thermal Method_. The thermal methods simply measure, in some way, the amount of heat which is produced by a received telephone current. When this current is allowed to pass through a conductor the effect of the heat generated in that conductor, is observed in one of three ways: by the expansion of the conductor, by its change in resistance, or by the production of an electromotive force in a thermo-electric couple heated by the conductor. Any one of these three ways can be used to get some idea of the amount of current which is received. None of them gives an accurate knowledge of the forms of the waves which cause the reproduction of speech in the telephone receiver. [Illustration: Fig. 14. Oscillogram of Telephone Currents] _Electromagnetic Method_. An electromagnetic device adapted to tell something of the magnitude of the telephone current and also something of its form, _i.e._, something of its various increases and decreases and also of its changes in direction is the oscillograph. An oscillograph is composed of a magnetic field formed by direct currents or by a permanent magnet, a turn of wire under mechanical tension in that field, and a mirror borne by the turn of wire, adapted to reflect a beam of light to a photographic film or to a rotating mirror. When a current is to be measured by the oscillograph, it is passed through the turn of wire in the magnetic field. While no current is passing, the wire does not move in the magnetic field and its mirror reflects a stationary beam of light. A photographic film moved in a direction normal to the axis of the turn of wire will have drawn upon it a straight line by the beam of light. If the beam of light, however, is moved by a current, from side to side at right angles to this axis, it will draw a wavy line on the photographic film and this wavy line will picture the alternations of that current and the oscillations of the molecules of air which carried the originating sound. Fig. 14 is a photograph of nine different vowel sounds which have caused the oscillograph to take their pictures. They are copies of records made by Mr. Bela Gati, assisted by Mr. Tolnai. The measuring instrument consisted of an oscillograph of the type described, the transmitter being of the carbon type actuated by a 2-volt battery. The primary current was transformed by an induction coil of the ordinary type and the transformed current was sent through a non-inductive resistance of 3,000 ohms. No condensers were placed in the circuit. It will be seen that the integral values of the curves, starting from zero, are variable. The positive and the negative portions of the curves are not equal, so that the solution of the individual harmonic motion is difficult and laborious. These photographs point out several facts very clearly. One is that the alternations of currents in the telephone line, like the motions of the molecules of air of the original sound, are highly complex and are not, as musical tones are, regular recurrences of equal vibrations. They show also that any vowel sound may be considered to be a regular recurrence of certain groups of vibrations of different amplitudes and of different frequencies. CHAPTER III ELECTRICAL SIGNALS Electric calls or signals are of two kinds: audible and visible. [Illustration: Fig. 15. Telegraph Sounder and Key] [Illustration: Fig. 16. Vibrating Bell] Audible Signals. _Telegraph Sounder._ The earliest electric signal was an audible one, being the telegraph sounder, or the Morse register considered apart from its registering function. Each telegraph sounder serves as an audible electric signal and is capable of signifying more than that the call is being made. Such a signal is operated by the making and breaking of current from a battery. An arrangement of this kind is shown in Fig. 15, in which pressure upon the key causes the current from the battery to energize the sounder and give one sharp audible rap of the lever upon the striking post. _Vibrating Bell_. The vibrating bell, so widely used as a door bell, is a device consequent to the telegraph. Its action is to give a series of blows on its gong when its key or push button closes the battery circuit. At the risk of describing a trite though not trivial thing, it may be said that when the contact _1_ of Fig. 16 is closed, current from the battery energizes the armature _2_, causing the latter to strike a blow on the gong and to break the line circuit as well, by opening the contact back of the armature. So de-energized, the armature falls back and the cycle is repeated until the button contact is released. A comparison of this action with that of the polarized ringer (to be described later) will be found of interest. [Illustration: Fig. 17. Elemental Magneto-Generator] _Magneto-Bell._ The magneto-bell came into wide use with the spread of telephone service. Its two fundamental parts are an alternating-current generator and a polarized bell-ringing device. Each had its counterpart long before the invention of the telephone, though made familiar by the latter. The alternating-current generator of the magneto-bell consists of a rotatable armature composed of a coil of insulated wire and usually a core of soft iron, its rotation taking place in a magnetic field. This field is usually provided by a permanent magnet, hence the name "magneto-generator." The purist in terms may well say, however, that every form whatever of the dynamo-electric generator is a magneto-generator, as magnetism is one link in every such conversion of mechanical power into electricity. The terms magneto-electric, magneto-generator, etc., involving the term "magneto," have come to imply the presence of _permanently_ magnetized steel as an element of the construction. In its early form, the magneto-generator consisted of the arrangement shown in Fig. 17, wherein a permanent magnet can rotate on an axis before an electromagnet having soft iron cores and a winding. Reversals of magnetism produce current in alternately reversing half-cycles, one complete rotation of the magnet producing one such cycle. Obviously the result would be the same if the magnet were stationary and the coils should rotate, which is the construction of more modern devices. The turning of the crank of a magneto-bell rotates the armature in the magnetic field by some form of gearing at a rate usually of the order of twenty turns per second, producing an alternating current of that frequency. This current is caused by an effective electromotive force which may be as great as 100 volts, produced immediately by the energy of the user. In an equipment using a magneto-telephone as both receiver and transmitter and a magneto-bell as its signal-sending machine, as was usual in 1877, it is interesting to note that the entire motive power for signals and speech transmission was supplied by the muscular tissues of the user--a case of working one's passage. [Illustration: Fig. 18. Extension of a Permanent Magnet] The alternating current from the generator is received and converted into sound by means of the _polarized ringer_, a device which is interesting as depending upon several of the electrical, mechanical, and magnetic actions which are the foundations of telephone engineering. [Illustration: Fig. 19. Extension of a Permanent Magnet] "Why the ringer rings" may be gathered from a study of Figs. 18 to 21. A permanent magnet will impart temporary magnetism to pieces of iron near it. In Fig. 18 two pieces of iron are so energized. The ends of these pieces which are nearest to the permanent magnet _1_ are of the opposite polarity to the end they approach, the free ends being of opposite polarity. In the figure, these free ends are marked _N_, meaning they are of a polarity to point north if free to point at all. English-speaking persons call this _north polarity_. Similarly, as in Fig. 19, any arrangement of iron near a permanent magnet always will have free poles of the same polarity as the end of the permanent magnet nearest them. A permanent magnet so related to iron forms part of a polarized ringer. So does an electromagnet composed of windings and iron cores. Fig. 20 reminds us of the law of electromagnets. If current flows from the plus towards the minus side, with the windings as drawn, polarities will be induced as marked. [Illustration: Fig. 20. Electromagnet] [Illustration: Fig. 21. Polarized Ringer] If, now, such an electromagnet, a permanent magnet, and a pivoted armature be related to a pair of gongs as shown in Fig. 21, a polarized ringer results. It should be noted that a permanent magnet has both its poles presented (though one of the poles is not actually attached) to two parts of the iron of the _electro_-magnet. The result is that the ends of the armature are of south polarity and those of the core are of north polarity. All the markings of Fig. 21 relate to the polarity produced by the permanent magnet. If, now, a current flow in the ringer winding from plus to minus, obviously the right-hand pole will be additively magnetized, the current tending to produce north magnetism there; also the left-hand pole will be subtractively magnetized, the current tending to produce south magnetism there. If the current be of a certain strength, relative to the certain ringer under study, magnetism in the left pole will be neutralized and that in the right pole doubled. Hence the armature will be attracted more by the right pole than by the left and will strike the right-hand gong. A reversal of current produces an opposite action, the left-hand gong being struck. The current ceasing, the armature remains where last thrown. [Illustration: OPERATOR'S EQUIPMENT Clement Automanual System.] It is important to note that the strength of action depends upon the strength of the current up to a certain point only. That depends upon the strength of the permanent magnet. Whenever the current is great enough just to neutralize the normal magnetism of one pole and to double that of the other, no increase in current will cause the device to ring any louder. This makes obvious the importance of a proper permanent magnetism and displays the fallacy of some effort to increase the output of various devices depending upon these principles. This discussion of magneto-electric signaling is introduced here because of a belief in its being fundamental. Chapter VIII treats of such a signaling in further detail. _Telephone Receiver._ The telephone receiver itself serves a useful purpose as an audible signal. An interrupted or alternating current of proper frequency and amount will produce in it a musical tone which can be heard throughout a large room. This fact enables a telephone central office to signal a subscriber who has left his receiver off the switch hook, so that normal conditions may be restored. Visible Signals. _Electromagnetic Signal._ Practical visual signals are of two general kinds: electromagnetic devices for moving a target or pointer, and incandescent lamps. The earliest and most widely used visible signal in telephone practice was the annunciator, having a shutter adapted to fall when the magnet is energized. Fig. 22 is such a signal. Shutter _1_ is held by the catch _2_ from dropping to the right by its own gravity. The name "gravity-drop" is thus obvious. Current energizing the core attracts the armature _3_, lifts the catch _2_, and the shutter falls. A simple modification of the gravity-drop produces the visible signal shown in Fig. 23. Energizing the core lifts a target so as to render it visible through an opening in the plate _1_. A contrast of color between the plate and the target heightens the effect. [Illustration: Fig. 22. Gravity-Drop] The gravity-drop is principally adapted to the magneto-bell system of signaling, where an alternating current is sent over the line to a central office by the operation of a bell crank at the subscriber's station, this current, lasting only as long as the crank is turned, energizes the drop, which may be restored by hand or otherwise and will remain latched. The visible signal is better adapted to lines in which the signaling is done by means of direct current, as, for example, in systems where the removal of the receiver from the hook at the subscriber's station closes the line circuit, causing current to flow through the winding of the visible signal and so displaying it until the receiver has been hung upon the hook or the circuit opened by some operation at the central office. Visible signals of the magnetic type of Fig. 23 have been widely used in connection with common-battery systems, both for line signals and for supervisory purposes, indicating the state and the progress of the connection and conversation. [Illustration: Fig. 23. Electromagnetic Visible Signal] [Illustration: Fig. 24. Lamp Signal and Lens] _Electric-Lamp Signal._ Incandescent electric lamps appeared in telephony as a considerable element about 1890. They are better than either form of mechanical visible signals because of three principal qualities: simplicity and ease of restoring them to normal as compared with drops; their compactness; and their greater prominence when displayed. Of the latter quality, one may say that they are more _insistent_, as they give out light instead of reflecting it, as do all other visible signals. In its best form, the lamp signal is mounted behind a hemispherical lens, either slightly clouded or cut in facets. This lens serves to distribute the rays of light from the lamp, with the result that the signal may be seen from a wide angle with the axis of the lens, as shown in Fig. 24. This is of particular advantage in connection with manual-switchboard connecting cords, as it enables the signals to be mounted close to and even among the cords, their great visible prominence when shining saving them from being hidden. The influence of the lamp signal was one of the potent ones in the development of the type of multiple switchboard which is now universal as the mechanism of large manual exchanges. The first large trial of such an equipment was in 1896 in Worcester, Mass. No large and successful multiple switchboard with any other type of signal has been built since that time. Any electric signal has upper and lower limits of current between which it is to be actuated. It must receive current enough to operate but not enough to become damaged by overheating. The magnetic types of visible signals have a wider range between these limits than have lamp signals. If current in a lamp is too little, its filament either will not glow at all or merely at a dull red, insufficient for a proper signal. If the current is too great, the filament is heated beyond its strength and parts at the weakest place. This range between current limits in magnetic visible signals is great enough to enable them to be used direct in telephone lines, the operating current through the line and signal in series with a fixed voltage at the central office being not harmfully great when the entire line resistance is shunted out at or near the central office. The increase of current may be as great as ten times without damage to the winding of such a signal. In lamps, the safe margin is much less. The current which just gives a sufficient lighting of the signal may be about doubled with safety to the filament of the lamp. Consequently it is not feasible to place the lamp directly in series with long exposed lines. A short circuit of such a line near the central office will burn it out. [Illustration: Fig. 25. Lamp Signal Controlled by Relay] The qualities of electromagnets and lamps in these respects are used to advantage by the lamp signal arrangement shown in Fig. 25. A relay is in series with the line and provides a large range of sensibility. It is able to carry any current the central-office current source can pass through it. The local circuit of the relay includes the lamp. Energizing the relay lights the lamp, and the reverse; the lamp is thus isolated from danger and receives the current best adapted to its needs. All lines are not long and when enclosed in cable or in well-insulated interior wire, may be only remotely in danger of being short-circuited. Such conditions exist in private-branch exchanges, which are groups of telephones, usually local to limited premises, connected to a switchboard on those premises. Such a situation permits the omission of the line relay, the lamp being directly in the line. Fig. 26 shows the extreme simplicity of the arrangement, containing no moving parts or costly elements. Lamps for such service have improved greatly since the demand began to grow. The small bulk permitted by the need of compactness, the high filament resistance required for simplicity of the general power scheme of the system, and the need of considerable sturdiness in the completed thing have made the task a hard one. The practical result, however, is a signal lamp which is highly satisfactory. [Illustration: Fig. 26. Lamp Signal Directly in Line] [Illustration: Fig. 27. Lamp Signal and Ballast] The nature of carbon and certain earths being that their conductivity _rises_ with the temperature and that of metals being that their conductivity _falls_ with the temperature, has enabled the Nernst lamp to be successful. The same relation of properties has enabled incandescent-lamp signals to be connected direct to lines without relays, but compensated against too great a current by causing the resistance in series with the lamp to be increased inversely as the resistance of the filament. Employment of a "ballast" resistance in this way is referred to in Chapter XI. In Fig. 27 is shown its relation to a signal lamp directly in the line. _1_ is the carbon-filament lamp; _2_ is the ballast. The latter's conductor is fine iron wire in a vacuum. The resistance of the lamp falls as that of the ballast rises. Within certain limits, these changes balance each other, widening the range of allowable change in the total resistance of the line. CHAPTER IV TELEPHONE LINES _The line is a path over which the telephone current passes from telephone to telephone._ The term "telephone line circuit" is equivalent. "Line" and "line circuit" mean slightly different things to some persons, "line" meaning the out-of-doors portion of the line and "line circuit" meaning the indoor portion, composed of apparatus and associated wiring. Such shades of meaning are inevitable and serve useful purposes. The opening definition hereof is accurate. A telephone line consists of two conductors. One of these conductors may be the earth; the other always is some conducting material other than the earth--almost universally it is of metal and in the form of a wire. A line using one wire and the earth as its pair of conductors has several defects, to be discussed later herein. Both conductors of a line may be wires, the earth serving as no part of the circuit, and this is the best practice. A line composed of one wire and the earth is called a _grounded line_; a line composed of two wires not needing the earth as a conductor is called a _metallic circuit_. In the earliest telephone practice, all lines were grounded ones. The wires were of iron, supported by poles and insulated from them by glass, earthenware, or rubber insulators. For certain uses, such lines still represent good practice. For telegraph service, they represent the present standard practice. Copper is a better conductor than iron, does not rust, and when drawn into wire in such a way as to have a sufficient tensile strength to support itself is the best available conductor for telephone lines. Only one metal surpasses it in any quality for the purpose: silver is a better conductor by 1 or 2 per cent. Copper is better than silver in strength and price. In the open country, telephone lines consist of bare wires of copper, of iron, of steel, or of copper-covered steel supported on insulators borne by poles. If the wires on the poles be many, cross-arms carry four to ten wires each and the insulators are mounted on pins in the cross-arms. If the wires on the poles be few, the insulators are mounted on brackets nailed to the poles. Wires so carried are called _open wires_. In towns and cities where many wires are to be carried along the same route, the wires are reduced in size, insulated by a covering over each, and assembled into a group. Such a bundle of insulated wires is called a _cable_. It may be drawn into a duct in the earth and be called an _underground cable_; it may be laid on the bottom of the sea or other water and be called a _submarine cable_; or it may be suspended on poles and be called an _aërial cable_. In the most general practice each wire is insulated from all others by a wrapping of paper ribbon, which covering is only adequate when very dry. Cables formed of paper-insulated wires, therefore, are covered by a seamless, continuous lead sheath, no part of the paper insulation of the wires being exposed to the atmosphere during the cable's entire life in service. Telephone cables for certain uses are formed of wires insulated with such materials as soft rubber, gutta-percha, and cotton or jute saturated with mineral compounds. When insulated with rubber or gutta-percha, no continuous lead sheath is essential for insulation, as those materials, if continuous upon the wire, insulate even when the cable is immersed in water. Sheaths and other armors can assist in protecting these insulating materials from mechanical injury, and often are used for that purpose. The uses to which such cables are suitable in telephony are not many, as will be shown. A wire supported on poles requires that it be large enough to support its own weight. The smaller the wire, the weaker it is, and with poles a given distance apart, the strength of the wire must be above a certain minimum. In regions where freezing occurs, wires in the open air can collect ice in winter and everywhere open wires are subject to wind pressure; for these reasons additional strength is required. Speaking generally, the practical and economical spacing of poles requires that wires, to be strong enough to meet the above conditions, shall have a diameter not less than .08 inch, if of hard-drawn copper, and .064 inch, if of iron or steel. The honor of developing ways of drawing copper wire with sufficient tensile strength for open-air uses belongs to Mr. Thomas B. Doolittle of Massachusetts. Lines whose lengths are limited to a few miles do not require a conductivity as great as that of copper wire of .08-inch diameter. A wire of that size weighs approximately 100 pounds per mile. Less than 100 pounds of copper per mile of wire will not give strength enough for use on poles; but as little as 10 pounds per mile of wire gives the necessary conductivity for the lines of the thousands of telephone stations in towns and cities. Open wires, being exposed to the elements, suffer damage from storms; their insulation is injured by contact with trees; they may make contact with electric power circuits, perhaps injuring apparatus, themselves, and persons; they endanger life and property by the possibility of falling; they and their cross-arm supports are less sightly than a more compact arrangement. Grouping small wires of telephone lines into cables has, therefore, the advantage of allowing less copper to be used, of reducing the space required, of improving appearance, and of increasing safety. On the other hand, this same grouping introduces negative advantages as well as the foregoing positive ones. It is not possible to talk as far or as well over a line in an ordinary cable as over a line of two open wires. Long-distance telephone circuits, therefore, have not yet been placed in cables for lengths greater than 200 or 300 miles, and special treatment of cable circuits is required to talk through them for even 100 miles. One may talk 2,000 miles over open wires. The reasons for the superiority of the open wires have to do with position rather than material. Obviously it is possible to insulate and bury any wire which can be carried in the air. The differences in the properties of lines whose wires are differently situated with reference to each other and surrounding things are interesting and important. A telephone line composed of two conductors always possesses four principal properties in some amount: (1) conductivity of the conductors; (2) electrostatic capacity between the conductors; (3) inductance of the circuit; (4) insulation of each conductor from other things. Conductivity of Conductors. The conductivity of a wire depends upon its material, its cross-section, its length, and its temperature. Conductivity of a copper wire, for example, increases in direct ratio to its weight, in inverse ratio to its length, and its conductivity falls as the temperature rises. Resistance is the reciprocal of conductivity and the properties, conductivity and resistance, are more often expressed in terms of resistance. The unit of the latter is the _ohm_; of the former the _mho_. A conductor having a resistance of 100 ohms has a conductivity of .01 mho. The exact correlative terms are _resistance_ and _conductance_, _resistivity_ and _conductivity_. The use of the terms as in the foregoing is in accordance with colloquial practice. Current in a circuit having resistance only, varies inversely as the resistance. Electromotive force being a cause, and resistance a state, current is the result. The formula of this relation, Ohm's law, is C = E/R _C_ being the current which results from _E_, the electromotive force, acting upon _R_, the resistance. The units are: of current, the ampere; of electromotive force, the volt; of resistance, the ohm. As the conductivity or resistance of a line is the property of controlling importance in telegraphy, a similar relation was expected in early telephony. As the current in the telephone line varies rapidly, certain other properties of the line assume an importance they do not have in telegraphy in any such degree. The importance that these properties assume is, that if they did not act and the resistance of the conductors alone limited speech, transmission would be possible direct from Europe to America over a pair of wires weighing 200 pounds per mile of wire, which is less than half the weight of the wire of the best long-distance land lines now in service. The distance from Europe to America is about twice as great as the present commercial radius by land lines of 435-pound wire. In other words, good speech is possible through a mere resistance twenty times greater than the resistance of the longest actual open-wire line it is possible to talk through. The talking ratio between a mere resistance and the resistance of a regular telephone cable is still greater. Electrostatic Capacity. It is the possession of electrostatic capacity which enables the condenser, of which the Leyden jar is a good example, to be useful in a telephone line. The simplest form of a condenser is illustrated in Fig. 28, in which two conducting surfaces are separated by an insulating material. The larger the surfaces, the closer they are together; and the higher the specific inductive capacity of the insulator, the greater the capacity of the device. An insulator used in this relation to two conducting surfaces is called the _dielectric_. [Illustration: Fig. 28. Simple Condenser] [Illustration: Fig. 29. Condenser Symbols] Two conventional signs are used to illustrate condensers, the upper one of Fig. 29 growing out of the original condenser of two metal plates, the lower one suggesting the thought of interleaved conductors of tin foil, as for many years was the practice in condenser construction. With relation to this property, a telephone line is just as truly a condenser as is any other arrangement of conductors and insulators. Assume such a line to be open at the distant end and its wires to be well insulated from each other and the earth. Telegraphy through such a line by ordinary means would be impossible. All that the battery or other source could do would be to cause current to flow into the line for an infinitesimal time, raising the wires to its potential, after which no current would flow. But, by virtue of electrostatic capacity, the condition is much as shown in Fig. 30. The condensers which that figure shows bridged across the line from wire to wire are intended merely to fix in the mind that there is a path for the transfer of electrical energy from wire to wire. [Illustration: Fig. 30. Line with Shunt Capacity] A simple test will enable two of the results of a short-circuiting capacity to be appreciated. Conceive a very short line of two wires to connect two local battery telephones. Such a line possesses negligible resistance, inductance, and shunt capacity. Its insulation is practically infinite. Let condensers be bridged across the line, one by one, while conversation goes on. The listening observer will notice that the sounds reaching his ear steadily grow less loud as the capacity across the line increases. The speaking observer will notice that the sounds he hears through the receiver in series with the line steadily grow louder as the capacity across the line increases. Fig. 31 illustrates the test. The speaker's observation in this test shows that increasing the capacity across the line increased the amount of current entering it. The hearer's observation in this test shows that increasing the capacity across the line decreased the amount of energy turned into sound at his receiver. [Illustration: Fig. 31. Test of Line with Varying Shunt Capacity] The unit of electrostatic capacity is the _farad_. As this unit is inconveniently large, for practical applications the unit _microfarad_--millionth of a farad--is employed. If quantities are known in microfarads and are to be used in calculations in which the values of the capacity require to be farads, care should be taken to introduce the proper corrective factor. The electrostatic capacity between the conductors of a telephone line depends upon their surface area, their length, their position, and the nature of the materials separating them from each other and from other things. For instance, in an open wire line of two wires, the electrostatic capacity depends upon the diameter of the wires, upon the length of the line, upon their distance apart, upon their distance above the earth, and upon the specific inductive capacity of the air. Air being so common an insulating medium, it is taken as a convenient material whose specific inductive capacity may be used as a basis of reference. Therefore, the specific inductive capacity of air is taken as unity. All solid matter has higher specific inductive capacity than air. The electrostatic capacity of two open wires .165 inch diameter, 1 ft. apart, and 30 ft. above the earth, is of the order of .009 microfarads per mile. This quantity would be higher if the wires were closer together; or nearer the earth; or if they were surrounded by a gas other than the air or hydrogen; or if the wires were insulated not by a gas but by any solid covering. As another example, a line composed of two wires of a diameter of .036 inch, if wrapped with paper and twisted into a pair as a part of a telephone-cable, has a mutual electrostatic capacity of approximately .08 microfarads per mile, this quantity being greater if the cable be more tightly compressed. The use of paper as an insulator for wires in telephone cables is due to its low specific inductive capacity. This is because the insulation of the wires is so largely dry air. Rubber and similar insulating materials give capacities as great as twice that of dry paper. The condenser or other capacity acts as an effective barrier to the steady flow of direct currents. Applying a fixed potential causes a mere rush of current to charge its surface to a definite degree, dependent upon the particular conditions. The condenser does not act as such a barrier to alternating currents, for it is possible to talk through a condenser by means of the alternating voice currents of telephony, or to pass through it alternating currents of much lower frequency. A condenser is used in series with a polarized ringer for the purpose of letting through alternating current for ringing the bell, and of preventing the flow of direct current. The degree to which the condenser allows alternating currents to pass while stopping direct currents, depends on the capacity of the condenser and on the frequencies of alternating current. The larger the condenser capacity or the higher the frequency of the alternations, the greater will be the current passing through the circuit. The degree to which the current is opposed by the capacity is the reactance of that capacity for that frequency. The formula is Capacity reactance = 1 /_C_[omega] wherein _C_ is the capacity in farads and [omega] is 2[pi]_n_, or twice 3.1416 times the frequency. All the foregoing leads to the generalization that the higher the frequency, the less the opposition of a capacity to an alternating current. If the frequency be zero, the reactance is infinite, _i.e._, the circuit is open to direct current. If the frequency be infinite, the reactance is zero, _i.e._, the circuit is as if the condenser were replaced by a solid conductor of no resistance. Compare this statement with the correlative generalization which follows the next thought upon inductance. Inductance of the Circuit. Inductance is the property of a circuit by which change of current in it tends to produce in itself and other conductors an electromotive force other than that which causes the current. Its unit is the _henry_. The inductance of a circuit is one henry when a change of one ampere per second produces an electromotive force of one volt. Induction _between_ circuits occurs because the circuits possess inductance; it is called _mutual induction_. Induction _within_ a circuit occurs because the circuit possesses inductance; it is called _self-induction_. Lenz' law says: _In all cases of electromagnetic induction, the induced currents have such a direction that their reaction tends to stop the motion which produced them_. [Illustration: Fig. 32. Spiral of Wire] [Illustration: Fig. 33. Spiral of Wire Around Iron Core] All conductors possess inductance, but straight wires used in lines have negligible inductance in most actual cases. All wires which are wound into coils, such as electromagnets, possess inductance in a greatly increased degree. A wire wound into a spiral, as indicated in Fig. 32, possesses much greater inductance than when drawn out straight. If iron be inserted into the spiral, as shown in Fig. 33, the inductance is still further increased. It is for the purpose of eliminating inductance that resistance coils are wound with double wires, so that current passing through such coils turns in one direction half the way and in the other direction the other half. A simple test will enable the results of a series inductance in a line to be appreciated. Conceive a very short line of two wires to connect two local battery telephones. Such a line possesses negligible resistance, inductance, and shunt capacity. Its insulation is practically infinite. Let inductive coils such as electromagnets be inserted serially in the wires of the line one by one, while conversation goes on. The listening observer will notice that the sounds reaching his ear steadily grow faint as the inductance in the line increases and the speaking observer will notice the same thing through the receiver in series with the line. Both observations in this test show that the amount of current entering and emerging from the line decreased as the inductance increased. Compare this with the test with bridged capacity and the loading of lines described later herein, observing the curious beneficial result when both hurtful properties are present in a line. The test is illustrated in Fig. 34. The degree in which any current is opposed by inductance is termed the reactance of that inductance. Its formula is Inductive reactance = _L_[omega] wherein _L_ is the inductance in henrys and [omega] is _2_[pi]_n_, or twice 3.1416 times the frequency. To distinguish the two kinds of reactance, that due to the capacity is called _capacity reactance_ and that due to inductance is called _inductive reactance_. All the foregoing leads to the generalization that the higher the frequency, the greater the opposition of an inductance to an alternating current. If the frequency be zero, the reactance is zero, _i.e._, the circuit conducts direct current as mere resistance. If the frequency be infinite, the reactance is infinite, _i.e._, the circuit is "open" to the alternating current and that current cannot pass through it. Compare this with the correlative generalization following the preceding thought upon capacity. [Illustration: Fig. 34. Test of Line with Varying Serial Inductance] Capacity and inductance depend only on states of matter. Their reactances depend on states of matter and actions of energy. In circuits having both resistance and capacity or resistance and inductance, both properties affect the passage of current. The joint reaction is expressed in ohms and is called _impedance_. Its value is the square root of the sum of the squares of the resistance and reactance, or, Z being impedance, ------------------------- / 1 Z = / R^{2} + ---------------- \/ C^{2}[omega]^{2} and -------------------------- Z = / R^{2} + L^{2}[omega]^{2} \/ the symbols meaning as before. In words, these formulas mean that, knowing the frequency of the current and the capacity of a condenser, or the frequency of the current and the inductance of a circuit (a line or piece of apparatus), and in either case the resistance of the circuit, one may learn the impedance by calculation. Insulation of Conductors. The fourth property of telephone lines, insulation of the conductors, usually is expressed in ohms as an insulation resistance. In practice, this property needs to be intrinsically high, and usually is measured by millions of ohms resistance from the wire of a line to its mate or to the earth. It is a convenience to employ a large unit. A million ohms, therefore, is called a _megohm_. In telephone cables, an insulation resistance of 500 megohms per mile at 60° Fahrenheit is the usual specification. So high an insulation resistance in a paper-insulated conductor is only attained by applying the lead sheath to the cable when its core is made practically anhydrous and kept so during the splicing and terminating of the cable. Insulation resistance varies inversely as the length of the conductor. If a piece of cable 528 feet long has an insulation resistance of 6,750 megohms, a mile (ten times as much) of such cable, will have an insulation resistance of 675 megohms, or one-tenth as great. Inductance vs. Capacity. The mutual capacity of a telephone line is greater as its wires are closer together. The self-induction of a telephone line is smaller as its wires are closer together. The electromotive force induced by the capacity of a line leads the impressed electromotive force by 90 degrees. The inductive electromotive force lags 90 degrees behind the impressed electromotive force. And so, in general, the natures of these two properties are opposite. In a cable, the wires are so close together that their induction is negligible, while their capacity is so great as to limit commercial transmission through a cable having .06 microfarads per mile capacity and 94 ohms loop resistance per mile, to a distance of about 30 miles. In the case of open wires spaced 12 inches apart, the limit of commercial transmission is greater, not only because the wires are larger, but because the capacity is lower and the inductance higher. Table I shows-the practical limiting conversation distance over uniform lines with present standard telephone apparatus. TABLE I Limiting Transmission Distances +-----------------------------+----------------------+ | SIZE AND GAUGE OF WIRE | LIMITING DISTANCE | +-----------------------------+----------------------+ | No. 8 B. W. G. copper | 900 miles | | 10 B. W. G. copper | 700 miles | | 10 B. & S. copper | 400 miles | | 12 N. B. S. copper | 400 miles | | 12 B. & S. copper | 240 miles | | 14 N. B. S. copper | 240 miles | | 8 B. W. G. iron | 135 miles | | 10 B. W. G. iron | 120 miles | | 12 B. W. G. iron | 90 miles | | 16 B. & S. cable, copper | 40 miles | | 19 B. & S. cable, copper | 30 miles | | 22 B. & S. cable, copper | 20 miles | +-----------------------------+----------------------+ In 1893, Oliver Heaviside proposed that the inductance of telephone lines be increased above the amount natural for the inter-axial spacing, with a view to counteracting the hurtful effects of the capacity. His meaning was that the increased inductance--a harmful quality in a circuit not having also a harmfully great capacity--would act oppositely to the capacity, and if properly chosen and applied, should decrease or eliminate distortion by making the line's effect on fundamentals and harmonics more nearly uniform, and as well should reduce the attenuation by neutralizing the action of the capacity in dissipating energy. There are two ways in which inductance might be introduced into a telephone line. As the capacity whose effects are to be neutralized is distributed uniformly throughout the line, the counteracting inductance must also be distributed throughout the line. Mere increase of distance between two wires of the line very happily acts both to increase the inductance and to lower the capacity; unhappily for practical results, the increase of separation to bring the qualities into useful neutralizing relation is beyond practical limits. The wires would need to be so far above the earth and so far apart as to make the arrangement commercially impossible. Practical results have been secured in increasing the distributed inductance by wrapping fine iron wire over each conductor of the line. Such a treatment increases the inductance and improves transmission. The most marked success has come as a result of the studies of Professor Michael Idvorsky Pupin. He inserts inductances in series with the wires of the line, so adapting them to the constants of the circuit that attenuation and distortion are diminished in a gratifying degree. This method of counteracting the effects of a distributed capacity by the insertion of localized inductance requires not only that the requisite total amount of inductance be known, but that the proper subdivision and spacing of the local portions of that inductance be known. Professor Pupin's method is described in a paper entitled "Wave Transmission Over Non-uniform Cables and Long-Distance Air Lines," read by him at a meeting of the American Institute of Electrical Engineers in Philadelphia, May 19, 1900. NOTE. United States Letters Patent were issued to Professor Pupin on June 19, 1900, upon his practical method of reducing attenuation of electrical waves. A paper upon "Propagation of Long Electric Waves" was read by Professor Pupin before the American Institute of Electrical Engineers on March 22, 1899, and appears in Vol. 15 of the Transactions of that society. The student will find these documents useful in his studies on the subject. He is referred also to "Electrical Papers" and "Electromagnetic Theory" of Oliver Heaviside. Professor Pupin likens the transmission of electric waves over long-distance circuits to the transmission of mechanical waves over a string. Conceive an ordinary light string to be fixed at one end and shaken by the hand at the other; waves will pass over the string from the shaken to the fixed end. Certain reflections will occur from the fixed end. The amount of energy which can be sent in this case from the shaken to the fixed point is small, but if the string be loaded by attaching bullets to it, uniformly throughout its length, it now may transmit much more energy to the fixed end. [Illustration: MAIN ENTRANCE AND PUBLIC OFFICE, SAN FRANCISCO HOME TELEPHONE COMPANY Contract Department on Left. Accounting Department on Right.] The addition of inductance to a telephone line is analogous to the addition of bullets to the string, so that a telephone line is said to be _loaded_ when inductances are inserted in it, and the inductances themselves are known as _loading coils_. Fig. 35 shows the general relation of Pupin loading coils to the capacity of the line. The condensers of the figure are merely conventionals to represent the condenser which the line itself forms. The inductances of the figure are the actual loading coils. [Illustration: Fig. 35. Loaded Line] The loading of open wires is not as successful in practice as is that of cables. The fundamental reason lies in the fact that two of the properties of open wires--insulation and capacity--vary with atmospheric change. The inserted inductance remaining constant, its benefits may become detriments when the other two "constants" change. The loading of cable circuits is not subject to these defects. Such loading improves transmission; saves copper; permits the use of longer underground cables than are usable when not loaded; lowers maintenance costs by placing interurban cables underground; and permits submarine telephone cables to join places not otherwise able to speak with each other. Underground long-distance lines now join or are joining Boston and New York, Philadelphia and New York, Milwaukee and Chicago. England and France are connected by a loaded submarine cable. There is no theoretical reason why Europe and America should not speak to each other. The student wishing to determine for himself what are the effects of the properties of lines upon open or cable circuits will find most of the subject in the following equation. It tells the value of _a_ in terms of the four properties, _a_ being the attenuation constant of the line. That is, the larger _a_ is, the more the voice current is reduced in passing over the line. The equation is ----------------------------------------------------------------------- / ----------------------------------------------- a= /½ /(R^{2}+L^{2}[omega]^{2})(S^{2}+C^{2}[omega]^{2} + ½(RS-LC[omega]^{2} \/ \/ The quantities are R = Resistance in ohms L = Inductance in henrys C = Mutual (shunt) capacity in farads [omega] = 2[pi]_n_ = 6.2832 times the frequency S = Shunt leakage in mhos The quantity _S_ is a measure of the combined direct-current conductance (reciprocal of insulation resistance) and the apparent conductance due to dielectric hysteresis. NOTE. An excellent paper, assisting such study, and of immediate practical value as helping the understanding of cables and their reasons, is that of Mr. Frank B. Jewett, presented at the Thousand Islands Convention of the American Institute of Electrical Engineers, July 1, 1909. Chapter 43 treats cables in further detail. They form a most important part of telephone wire-plant practice, and their uses are becoming wider and more valuable. Possible Ways of Improving Transmission. Practical ways of improving telephone transmission are of two kinds: to improve the lines and to improve the apparatus. The foregoing shows what are the qualities of lines and the ways they require to be treated. Apparatus treatment, in the present state of the art, is addressed largely to the reduction of losses. Theoretical considerations seem to show, however, that great advance in apparatus effectiveness still is possible. More powerful transmitters--and more _faithful_ ones--more sensitive and accurate receivers, and more efficient translating devices surely are possible. Discovery may need to intervene, to enable invention to restimulate. In both telegraphy and telephony, the longer the line the weaker the current which is received at the distant end. In both telegraphy and telephony, there is a length of line with a given kind and size of wire and method of construction over which it is just possible to send intelligible speech or intelligible signals. A repeater, in telegraphy, is a device in the form of a relay which is adapted to receive these highly attenuated signal impulses and to re-transmit them with fresh power over a new length of line. An arrangement of two such relays makes it possible to telegraph both ways over a pair of lines united by such a repeater. It is practically possible to join up several such links of lines to repeating devices and, if need be, even submarine cables can be joined to land lines within practical limits. If it were necessary, it probably would be possible to telegraph around the world in this way. If it were possible to imitate the telegraph repeater in telephony, attenuated voice currents might be caused to actuate it so as to send on those voice currents with renewed power over a length of line, section by section. Such a device has been sought for many years, and it once was quoted in the public press that a reward of one million dollars had been offered by Charles J. Glidden for a successful device of that kind. The records of the patent offices of the world show what effort has been made in that direction and many more devices have been invented than have been patented in all the countries together. Like some other problems in telephony, this one seems simpler at first sight than it proves to be after more exhaustive study. It is possible for any amateur to produce at once a repeating device which will relay telephone circuits in one direction. It is required, however, that in practice the voice currents be relayed in both directions, and further, that the relay actually augment the energy which passes through it; that is, that it will send on a more powerful current than it receives. Most of the devices so far invented fail in one or the other of these particulars. Several ways have been shown of assembling repeating devices which will talk both ways, but not many assembling repeating devices have been shown that will talk both ways and augment in both directions. [Illustration: Fig. 36. Shreeve Repeater and Circuit] Practical repeaters have been produced, however, and at least one type is in daily successful use. It is not conclusively shown even of it that it augments in the same degree all of the voice waves which reach it, or even that it augments some of them at all. Its action, however, is distinctly an improvement in commercial practice. It is the invention of Mr. Herbert E. Shreeve and is shown in Fig. 39. Primarily it consists of a telephone receiver, of a particular type devised by Gundlach, associated with a granular carbon transmitter button. It is further associated with an arrangement of induction coils or repeating coils, the object of these being to accomplish the two-way action, that is, of speaking in both directions and of preventing reactive interference between the receiving and transmitting elements. The battery _1_ energizes the field of the receiving element; the received line current varies that field; the resulting motion varies the resistance of the carbon button and transforms current from battery _2_ into a new alternating line current. By reactive interference is meant action whereby the transmitter element, in emitting a wave, affects its own controlling receiver element, thus setting up an action similar to that which occurs when the receiver of a telephone is held close to its transmitter and humming or singing ensues. No repeater is successful unless it is free from this reactive interference. [Illustration: Fig. 37. Mercury-Arc Telephone Relay] Enough has been accomplished by practical tests of the Shreeve device and others like it to show that the search for a method of relaying telephone voice currents is not looking for a pot of gold at the end of the rainbow. The most remarkable truth established by the success of repeaters of the Shreeve type is that a device embodying so large inertia of moving parts can succeed at all. If this mean anything, it is that a device in which inertia is absolutely eliminated might do very much better. Many of the methods already proposed by inventors attack the problem in this way and one of the most recent and most promising ways is that of Mr. J.B. Taylor, the circuit of whose telephone-relay patent is shown in Fig. 37. In it, _1_ is an electromagnet energized by voice currents; its varying field varies an arc between the electrodes _2-2_ and _3_ in a vacuum tube. These fluctuations are transformed into line currents by the coil _4_. CHAPTER V TRANSMITTERS Variable Resistance. As already pointed out in Chapter II, the variable-resistance method of producing current waves, corresponding to sound waves for telephonic transmission, is the one that lends itself most readily to practical purposes. Practically all telephone transmitters of today employ this variable-resistance principle. The reason for the adoption of this method instead of the other possible ones is that the devices acting on this principle are capable, with great simplicity of construction, of producing much more powerful results than the others. Their simplicity is such as to make them capable of being manufactured at low cost and of being used successfully by unskilled persons. Materials. Of all the materials available for the variable-resistance element in telephone transmitters, carbon is by far the most suitable, and its use is well nigh universal. Sometimes one of the rarer metals, such as platinum or gold, is to be found in commercial transmitters as part of the resistance-varying device, but, even when this is so, it is always used in combination with carbon in some form or other. Most of the transmitters in use, however, depend solely upon carbon as the conductive material of the variable-resistance element. Arrangement of Electrodes. Following the principles pointed out by Hughes, the transmitters of today always employ as their variable-resistance elements one or more loose contacts between one or more pairs of electrodes, which electrodes, as just stated, are usually of carbon. Always the arrangement is such that the sound waves will vary the intimacy of contact between the electrodes and, therefore, the resistance of the path through the electrodes. A multitude of arrangements have been proposed and tried. Sometimes a single pair of electrodes has been employed having a single point of loose contact between them. These may be termed single-contact transmitters. Sometimes the variable-resistance element has included a greater number of electrodes arranged in multiple, or in series, or in series-multiple, and these have been termed multiple-electrode transmitters, signifying a plurality of electrodes. A later development, an outgrowth of the multiple-electrode transmitter, makes use of a pair of principal electrodes, between which is included a mass of finely divided carbon in the form of granules or small spheres or pellets. These, regardless of the exact form of the carbon particles, are called granular-carbon transmitters. [Illustration: Fig. 38. Blake Transmitter] Single Electrode. _Blake_. The most notable example of the single-contact transmitter is the once familiar Blake instrument. At one time this formed a part of the standard equipment of almost every telephone in the United States, and it was also largely used abroad. Probably no transmitter has ever exceeded it in clearness of articulation, but it was decidedly deficient in power in comparison with the modern transmitters. In this instrument, which is shown in Fig. 38, the variable-resistance contact was that between a carbon and a platinum electrode. The diaphragm _1_ was of sheet iron mounted, as usual in later transmitters, in a soft rubber gasket _2_. The whole diaphragm was mounted in a cast-iron ring _3_, supported on the inside of the box containing the entire instrument. The front electrode _4_ was mounted on a light spring _5_, the upper end of which was supported by a movable bar or lever _6_, flexibly supported on a spring _7_ secured to the casting which supported the diaphragm. The tension of this spring _5_ was such as to cause the platinum point to press lightly away from the center of the diaphragm. The rear electrode was of carbon in the form of a small block _9_, secured in a heavy brass button _10_. The entire rear electrode structure was supported on a heavier spring _11_ carried on the same lever as the spring _5_. The tension of this latter spring was such as to press against the front electrode and, by its greater strength, press this against the center of the diaphragm. The adjustment of the instrument was secured by means of the screw _12_, carried in a lug extending rearwardly from the diaphragm supporting casting, this screw, by its position, determining the strength with which the rear electrode pressed against the front electrode and that against the diaphragm. This instrument was ordinarily mounted in a wooden box together with the induction coil, which is shown in the upper portion of the figure. The Blake transmitter has passed almost entirely out of use in this country, being superseded by the various forms of granular instruments, which, while much more powerful, are not perhaps capable of producing quite such clear and distinct articulation. The great trouble with the single-contact transmitters, such as the Blake, was that it was impossible to pass enough current through the single point of contact to secure the desired power of transmission without overheating the contact. If too much current is sent through such transmitters, an undue amount of heat is generated at the point of contact and a vibration is set up which causes a peculiar humming or squealing sound which interferes with the transmission of other sounds. Multiple Electrode. To remedy this difficulty the so-called multiple-electrode transmitter was brought out. This took a very great number of forms, of which the one shown in Fig. 39 is typical. The diaphragm shown at _1_, in this particular form, was made of thin pine wood. On the rear side of this, suspended from a rod _3_ carried in a bracket _4_, were a number of carbon rods or pendants _5_, loosely resting against a rod _2_, carried on a bracket _6_ also mounted on the rear of the diaphragm. The pivotal rod _3_ and the rod _2_, against which the pendants rested, were sometimes, like the pendant rods, made of carbon and sometimes of metal, such as brass. When the diaphragm vibrated, the intimacy of contact between the pendant rod _5_ and the rod _2_ was altered, and thus the resistance of the path through all of the pendant rods in multiple was changed. [Illustration: Fig. 39. Multiple-Electrode Transmitter] A multitude of forms of such transmitters came into use in the early eighties, and while they in some measure remedied the difficulty encountered with the Blake transmitter, _i.e._, of not being able to carry a sufficiently large current, they were all subject to the effects of extreme sensitiveness, and would rattle or break when called upon to transmit sounds of more than ordinary loudness. Furthermore, the presence of such large masses of material, which it was necessary to throw into vibration by the sound waves, was distinctly against this form of transmitter. The inertia of the moving parts was so great that clearness of articulation was interfered with. Granular Carbon. The idea of employing a mass of granular carbon, supported between two electrodes, one of which vibrated with the sound waves and the other was stationary, was proposed by Henry Hunnings in the early eighties. While this idea forms the basis of all modern telephone transmitters, yet it did not prevent the almost universal adoption of the single-contact form of instrument during the next decade. Western Electric Solid-Back Transmitter. In the early nineties, however, the granular-carbon transmitter came into its own with the advent and wide adoption of the transmitter designed by Anthony C. White, known as the _White_, or _solid-back_, transmitter. This has for many years been the standard instrument of the Bell companies operating throughout the United States, and has found large use abroad. A horizontal cross-section of this instrument is shown in Fig. 40, and a rear view of the working parts in Fig. 41. The working parts are all mounted on the front casting _1_. This is supported in a cup _2_, in turn supported on the lug _3_, which is pivoted on the transmitter arm or other support. The front and rear electrodes of this instrument are formed of thin carbon disks shown in solid black. The rear electrode, the larger one of these disks, is securely attached by solder to the face of a brass disk having a rearwardly projecting screw-threaded shank, which serves to hold it and the rear electrode in place in the bottom of a heavy brass cup _4_. The front electrode is mounted on the rear face of a stud. Clamped against the head of this stud, by a screw-threaded clamping ring _7_, is a mica washer, or disk _6_. The center portion of this mica washer is therefore rigid with respect to the front electrode and partakes of its movements. The outer edge of this mica washer is similarly clamped against the front edge of the cup _4_, a screw-threaded ring _9_ serving to hold the edge of the mica rigidly against the front of the cup. The outer edge of this washer is, therefore, rigid with respect to the rear electrode, which is fixed. Whatever relative movement there is between the two electrodes must, therefore, be permitted by the flexing of the mica washer. This mica washer not only serves to maintain the electrodes in their normal relative positions, but also serves to close the chamber which contains the electrodes, and, therefore, to prevent the granular carbon, with which the space between the electrodes is filled, from falling out. [Illustration: Fig. 40. White Solid-Back Transmitter] The cup _4_, containing the electrode chamber, is rigidly fastened with respect to the body of the transmitter by a rearwardly projecting shank held in a bridge piece _8_ which is secured at its ends to the front block. The needed rigidity of the rear electrode is thus obtained and this is probably the reason for calling the instrument the _solid-back_. The front electrode, on the other hand, is fastened to the center of the diaphragm by means of a shank on the stud, which passes through a hole in the diaphragm and is clamped thereto by two small nuts. Against the rear face of the diaphragm of this transmitter there rest two damping springs. These are not shown in Fig. 40 but are in Fig. 41. They are secured at one end to the rear flange of the front casting _1_, and bear with their other or free ends against the rear face of the diaphragm. The damping springs are prevented from coming into actual contact with the diaphragm by small insulating pads. The purpose of the damping springs is to reduce the sensitiveness of the diaphragm to extraneous sounds. As a result, the White transmitter does not pick up all of the sounds in its vicinity as readily as do the more sensitive transmitters, and thus the transmission is not interfered with by extraneous noises. On the other hand, the provision of these heavy damping springs makes it necessary that this transmitter shall be spoken into directly by the user. [Illustration: Fig. 41. White Solid-Back Transmitter] The action of this transmitter is as follows: Sound waves are concentrated against the center of the diaphragm by the mouth-piece, which is of the familiar form. These waves impinge against the diaphragm, causing it to vibrate, and this, in turn, produces similar vibrations in the front electrode. The vibrations of the front electrode are permitted by the elasticity of the mica washer _6_. The rear electrode is, however, held stationary within the heavy chambered block _4_ and which in turn is held immovable by its rigid mounting. As a result, the front electrode approaches and recedes from the rear electrode, thus compressing and decompressing the mass of granular carbon between them. As a result, the intimacy of contact between the electrode plates and the granules and also between the granules themselves is altered, and the resistance of the path from one electrode to the other through the mass of granules is varied. New Western Electric Transmitter. The White transmitter was the prototype of a large number of others embodying the same features of having the rear electrode mounted in a stationary cup or chamber and the front electrode movable with the diaphragm, a washer of mica or other flexible insulating material serving to close the front of the electrode chamber and at the same time to permit the necessary vibration of the front electrode with the diaphragm. [Illustration: Fig. 42. New Western Electric Transmitter] One of these transmitters, embodying these same features but with modified details, is shown in Fig. 42, this being the new transmitter manufactured by the Western Electric Company. In this the bridge of the original White transmitter is dispensed with, the electrode chamber being supported by a pressed metal cup _1_, which supports the chamber as a whole. The electrode cup, instead of being made of a solid block as in the White instrument, is composed of two portions, a cylindrical or tubular portion _2_ and a back _3_. The cylindrical portion is externally screw-threaded so as to engage an internal screw thread in a flanged opening in the center of the cup _1_. By this means the electrode chamber is held in place in the cup _1_, and by the same means the mica washer _4_ is clamped between the flange in this opening and the tubular portion _2_ of the electrode chamber. The front electrode is carried, as in the White transmitter, on the mica washer and is rigidly attached to the center of the diaphragm so as to partake of the movement thereof. It will be seen, therefore, that this is essentially a White transmitter, but with a modified mounting for the electrode chamber. A feature in this transmitter that is not found in the White transmitter is that both the front and the rear electrodes, in fact, the entire working portions of the transmitter, are insulated from the exposed metal parts of the instrument. This is accomplished by insulating the diaphragm and the supporting cup _1_ from the transmitter front. The terminal _5_ on the cup _1_ forms the electrical connection for the rear electrode, while the terminal _6_, which is mounted _on_ but insulated _from_ the cup _1_ and is connected with the front electrode by a thin flexible connecting strip, forms the electrical connection for the front electrode. Kellogg Transmitter. The transmitter of the Kellogg Switchboard and Supply Company, originally developed by Mr. W.W. Dean and modified by his successors in the Kellogg Company, is shown in Fig. 43. In this, the electrode chamber, instead of being mounted in a stationary and rigid position, as in the case of the White instrument, is mounted on, and, in fact, forms a part of the diaphragm. The electrode which is associated with the mica washer instead of moving with the diaphragm, as in the White instrument, is rigidly connected to a bridge so as to be as free as possible from all vibrations. Referring to Fig. 43, which is a horizontal cross-section of the instrument, _1_ indicates the diaphragm. This is of aluminum and it has in its center a forwardly deflected portion forming a chamber for the electrodes. The front electrode _2_ of carbon is backed by a disk of brass and rigidly secured in the front of this chamber, as clearly indicated. The rear electrode _3_, also of carbon, is backed by a disk of brass, and is clamped against the central portion of a mica disk by means of the enlarged head of stud _6_. A nut _7_, engaging the end of a screw-threaded shank from the back of the rear electrode, serves to bind these two parts together securely, clamping the mica washer between them. The outer edge of the mica washer is clamped to the main diaphragm _1_ by an aluminum ring and rivets, as clearly indicated. It is seen, therefore, that the diaphragm itself contains the electrode chamber as an integral part thereof. The entire structure of the diaphragm, the front and back electrodes, and the granular carbon within are permanently assembled in the factory and cannot be dissociated without destroying some of the parts. The rear electrode is held rigidly in place by the bridge _5_ and the stud _6_, this stud passing through a block _9_ mounted on the bridge but insulated from it. The stud _6_ is clamped in the block _9_ by means of the set screw _8_, so as to hold the rear electrode in proper position after this position has been determined. [Illustration: Fig. 43. Kellogg Transmitter] In this transmitter, as in the transmitter shown in Fig. 42, all of the working parts are insulated from the exposed metal casing. The diaphragm is insulated from the front of the instrument by means of a washer _4_ of impregnated cloth, as indicated. The rear electrode is insulated from the other portions of the instrument by means of the mica washer and by means of the insulation between the block _9_ and the bridge _5_. The terminal for the rear electrode is mounted on the block _9_, while the terminal for the front electrode, shown at _10_, is mounted on, but insulated from, the bridge. This terminal _10_ is connected with the diaphragm and therefore with the front electrode by means of a thin, flexible metallic connection. This transmitter is provided with damping springs similar to those of the White instrument. It is claimed by advocates of this type of instrument that, in addition to the ordinary action due to the compression and decompression of the granular carbon between the electrodes, there exists another action due to the agitation of the granules as the chamber is caused to vibrate by the sound waves. In other words, in addition to the ordinary action, which may be termed _the piston action between the electrodes_, it is claimed that the general shaking-up effect of the granules when the chamber vibrates produces an added effect. Certain it is, however, that transmitters of this general type are very efficient and have proven their capability of giving satisfactory service through long periods of time. Another interesting feature of this instrument as it is now manufactured is the use of a transmitter front that is struck up from sheet metal rather than the employment of a casting as has ordinarily been the practice. The formation of the supporting lug for the transmitter from the sheet metal which forms the rear casing or shell of the instrument is also an interesting feature. Automatic Electric Company Transmitter. The transmitter of the Automatic Electric Company, of Chicago, shown in Fig. 44, is of the same general type as the one just discussed, in that the electrode chamber is mounted on and vibrates with the diaphragm instead of being rigidly supported on the bridge as in the case of the White or solid-back type of instrument. In this instrument the transmitter front _1_ is struck up from sheet metal and contains a rearwardly projecting flange, carrying an internal screw thread. A heavy inner cup _2_, together with the diaphragm _3_, form an enclosure containing the electrode chamber. The diaphragm is, in this case, permanently secured at its edge to the periphery of the inner cup _2_ by a band of metal _4_ so formed as to embrace the edges of both the cup and the diaphragm and permanently lock them together. This inner chamber is held in place in the transmitter front _1_ by means of a lock ring _5_ externally screw-threaded to engage the internal screw-thread on the flange on the front. The electrode chamber proper is made in the form of a cup, rigidly secured to the diaphragm so as to move therewith, as clearly indicated. The rear electrode is mounted on a screw-threaded stud carried in a block which is fitted to a close central opening in the cup _2_. This transmitter does not make use of a mica washer or diaphragm, but employs a felt washer which surrounds the shank of the rear electrode and serves to close and seal the carbon containing cup. By this means the granular carbon is retained in the chamber and the necessary flexibility or freedom of motion is permitted between the front and the rear electrodes. As in the Kellogg and the later Bell instruments, the entire working parts of this transmitter are insulated from the metal containing case, the inner chamber, formed by the cup _2_ and the diaphragm _3_, being insulated from the transmitter front and its locking ring by means of insulating washers, as shown. Fig. 44. Automatic Electric Company Transmitter Monarch Transmitter. The transmitter of the Monarch Telephone Manufacturing Company, shown in Fig. 45, differs from both the stationary-cup and the vibrating-cup types, although it has the characteristics of both. It might be said that it differs from each of these two types of transmitters in that it has the characteristics of both. This transmitter, it will be seen, has two flexible mica washers between the electrodes and the walls of the electrode cup. The front and the back electrodes are attached to the diaphragm and the bridge, respectively, by a method similar to that employed in the solid-back transmitters, while the carbon chamber itself is free to vibrate with the diaphragm as is characteristic of the Kellogg transmitter. [Illustration: Fig. 45. Monarch Transmitter] An aluminum diaphragm is employed, the circumferential edge of which is forwardly deflected to form a seat. The edge of the diaphragm rests _against_ and is separated _from_ the brass front by means of a one-piece gasket of specially treated linen. This forms an insulator which is not affected by heat or moisture. As in the transmitters previously described, the electrodes are firmly soldered to brass disks which have solid studs extending from their centers. In the case of both the front and the rear electrodes, a mica disk is placed over the supporting stud and held in place by a brass hub which has a base of the same size as the electrode. The carbon-chamber wall consists of a brass ring to which are fastened the mica disks of the front and the back electrodes by means of brass collars clamped over the edge of the mica and around the rim of the brass ring forming the chamber. [Illustration: MAIN OFFICE BUILDING, BERKELEY, CALIFORNIA Containing Automatic Equipment, Forming Part of Larger System Operating in San Francisco and Vicinity. Bay Cities Home Telephone Company.] Electrodes. The electrode plates of nearly all modern transmitters are of specially treated carbon. These are first copper-plated and soldered to their brass supporting disks. After this they are turned and ground so as to be truly circular in form and to present absolutely flat faces toward each other. These faces are then highly polished and the utmost effort is made to keep them absolutely clean. Great pains are taken to remove from the pores of the carbon, as well as from the surface, all of the acids or other chemicals that may have entered them during the process of electroplating them or of soldering them to the brass supporting disk. That the two electrodes, when mounted in a transmitter, should be parallel with each other, is an item of great importance as will be pointed out later. In a few cases, as previously stated, gold or platinum has been substituted for the carbon electrodes in transmitters. These are capable of giving good results when used in connection with the proper form of granular carbon, but, on the whole, the tendency has been to abandon all forms of electrode material except carbon, and its use is now well nigh universal. _Preparation of Carbon_. The granular carbon is prepared from carefully selected anthracite coal, which is specially treated by roasting or "re-carbonizing" and is then crushed to approximately the proper fineness. The crushed carbon is then screened with extreme care to eliminate all dust and to retain only granules of uniform size. Packing. In the earlier forms of granular-carbon transmitters a great deal of trouble was experienced due to the so-called packing of the instrument. This, as the term indicates, was a trouble due to the tendency of the carbon granules to settle into a compact mass and thus not respond to the variable pressure. This was sometimes due to the presence of moisture in the electrode chamber; sometimes to the employment of granules of varying sizes, so that they would finally arrange themselves under the vibration of the diaphragm into a fairly compact mass; or sometimes, and more frequently, to the granules in some way wedging the two electrodes apart and holding them at a greater distance from each other than their normal distance. The trouble due to moisture has been entirely eliminated by so sealing the granule chambers as to prevent the entrance of moisture. The trouble due to the lack of uniformity in size of the granules has been entirely eliminated by making them all of one size and by making them of sufficient hardness so that they would not break up into granules of smaller size. The trouble due to the settling of the granules and wedging the electrodes apart has been practically eliminated in well-designed instruments, by great mechanical nicety in manufacture. Almost any transmitter may be packed by drawing the diaphragm forward so as to widely separate the electrodes. This allows the granules to settle to a lower level than they normally occupy and when the diaphragm is released and attempts to resume its normal position it is prevented from doing so by the mass of granules between. Transmitters of the early types could be packed by placing the lips against the mouthpiece and drawing in the breath. The slots now provided at the base of standard mouthpieces effectually prevent this. In general it may be said that the packing difficulty has been almost entirely eliminated, not by the employment of remedial devices, such as those often proposed for stirring up the carbon, but by preventing the trouble by the design and manufacture of the instruments in such forms that they will not be subject to the evil. Carrying Capacity. Obviously, the power of a transmitter is dependent on the amount of current that it may carry, as well as on the amount of variation that it may make in the resistance of the path through it. Granular carbon transmitters are capable of carrying much heavier current than the old Blake or other single or multiple electrode types. If forced to carry too much current, however, the same frying or sizzling sound is noticeable as in the earlier types. This is due to the heating of the electrodes and to small arcs that occur between the electrodes and the granules. One way to increase the current-carrying capacity of a transmitter is to increase the area of its electrodes, but a limit is soon reached in this direction owing to the increased inertia of the moving electrode, which necessarily comes with its larger size. The carrying capacity of transmitters may also be increased by providing special means for carrying away the heat generated in the variable-resistance medium. Several schemes have been proposed for this. One is to employ unusually heavy metal for the electrode chamber, and this practice is best exemplified in the White solid-back instrument. It has also been proposed by others to water-jacket the electrode chamber, and also to keep it cool by placing it in close proximity to the relatively cool joints of a thermopile. Neither of these two latter schemes seems to be warranted in ordinary commercial practice. Sensitiveness. In all the transmitters so far discussed damping springs of one form or another have been employed to reduce the sensitiveness of the instrument. For ordinary commercial use too great a degree of sensitiveness is a fault, as has already been pointed out. There are, however, certain adaptations of the telephone transmitter which make a maximum degree of sensitiveness desirable. One of these adaptations is found in the telephone equipments for assisting partially deaf people to hear. In these the transmitter is carried on some portion of the body of the deaf person, the receiver is strapped or otherwise held at his ear, and a battery for furnishing the current is carried in his pocket. It is not feasible, for this sort of use, that the sound which this transmitter is to reproduce shall always occur immediately in front of the transmitter. It more often occurs at a distance of several feet. For this reason the transmitter is made as sensitive as possible, and yet is so constructed that it will not be caused to produce too loud or unduly harsh sounds in response to a loud sound taking place immediately in front of it. Another adaptation of such highly sensitive transmitters is found in the special intercommunicating telephone systems for use between the various departments or desks in business offices. In these it is desirable that the transmitter shall be able to respond adequately to sounds occurring anywhere in a small-sized room, for instance. Acousticon Transmitter. In Fig. 46 is shown a transmitter adapted for such use. This has been termed by its makers the _acousticon transmitter_. Like all the transmitters previously discussed, this is of the variable-resistance type, but it differs from them all in that it has no damping springs; in that carbon balls are substituted for carbon granules; and in that the diaphragm itself serves as the front electrode. This transmitter consists of a cup _1_, into which is set a cylindrical block _2_, in one face of which are a number of hemispherical recesses. The diaphragm _3_ is made of thin carbon and is so placed in the transmitter as to cover the openings of the recesses in the carbon block, and lie close enough to the carbon block, without engaging it, to prevent the carbon particles from falling out. The diaphragm thus serves as the front electrode and the carbon block as the rear electrode. The recesses in the carbon block are about two-thirds filled with small carbon balls, which are about the size of fine sand. The front piece _4_ of the transmitter is of sheet metal and serves to hold the diaphragm in place. To admit the sound waves it is provided with a circular opening opposite to and about the size of the rear electrode block. On this front piece are mounted the two terminals of the transmitter, connected respectively to the two electrodes, terminal _5_ being insulated from the front piece and connected by a thin metal strip with the diaphragm, while terminal _6_ is mounted directly on the front piece and connected through the cup _1_ with the carbon block _2_, or back electrode of the transmitter. [Illustration: Fig 46. Acousticon Transmitter] When this transmitter is used in connection with outfits for the deaf, it is placed in a hard rubber containing case, consisting of a hollow cylindrical piece _7_, which has fastened to it a cover _8_. This cover has a circular row of openings or holes near its outer edge, as shown at _9_, through which the sound waves may pass to the chamber within, and thence find their way through the round hole in the center of the front plate _4_ to the diaphragm _3_. It is probable also that the front face of the cover _8_ of the outer case vibrates, and in this way also causes sound waves to impinge against the diaphragm. This arrangement provides a large receiving surface for the sound waves, but, owing to the fact that the openings in the containing case are not opposite the opening in the transmitter proper, the sound waves do not impinge directly against the diaphragm. This peculiar arrangement is probably the result of an endeavor to prevent the transmitter from being too strongly actuated by violent sounds close to it. Instruments of this kind are very sensitive and under proper conditions are readily responsive to words spoken in an ordinary tone ten feet away. [Illustration: Fig. 47. Switchboard Transmitter] Switchboard Transmitter. Another special adaptation of the telephone transmitter is that for use of telephone operators at central-office switchboards. The requirements in this case are such that the operator must always be able to speak into the transmitter while seated before the switchboard, and yet allow both of her hands to be free for use. This was formerly accomplished by suspending an ordinary granular-carbon transmitter in front of the operator, but a later development has resulted in the adoption of the so-called breast transmitter, shown in Fig. 47. This is merely an ordinary granular-carbon transmitter mounted on a plate which is strapped on the breast of the operator, the transmitter being provided with a long curved mouthpiece which projects in such a manner as to lie just in front of the operator's lips. This device has the advantage of automatically following the operator in her movements. The breast transmitter shown in Fig. 47, is that of the Dean Electric Company. [Illustration: Fig. 48. Transmitter Symbols] Conventional Diagram. There are several common ways of illustrating transmitters in diagrams of circuits in which they are employed. The three most common ways are shown in Fig. 48. The one at the left is supposed to be a side view of an ordinary instrument, the one in the center a front view, and the one at the right to be merely a suggestive arrangement of the diaphragm and the rear electrode. The one at the right is best and perhaps most common; the center one is the poorest and least used. CHAPTER VI RECEIVERS The telephone receiver is the device which translates the energy of the voice currents into the energy of corresponding sound waves. All telephone receivers today are of the electromagnetic type, the voice currents causing a varying magnetic pull on an armature or diaphragm, which in turn produces the sound waves corresponding to the undulations of the voice currents. Early Receivers. The early forms of telephone receivers were of the _single-pole_ type; that is, the type wherein but one pole of the electromagnet was presented to the diaphragm. The single-pole receiver that formed the companion piece to the old Blake transmitter and that was the standard of the Bell companies for many years, is shown in Fig. 49. While this has almost completely passed out of use, it may be profitably studied in order that a comparison may be made between certain features of its construction and those of the later forms of receivers. The coil of this receiver was wound on a round iron core _2_, flattened at one end to afford means for attaching the permanent magnet. The permanent magnet was of laminated construction, consisting of four hard steel bars _1_, extending nearly the entire length of the receiver shell. These steel bars were all magnetized separately and placed with like poles together so as to form a single bar magnet. They were laid together in pairs so as to include between the pairs the flattened end of the pole piece _2_ at one end and the flattened portion of the tail piece _3_ at the other end. This whole magnet structure, including the core, the tail piece, and the permanently magnetized steel bars, was clamped together by screws as shown. The containing shell was of hard rubber consisting of three pieces, the barrel _4_, the ear-piece _5_, and the tail cap _6_. The barrel and the ear piece engaged each other by means of a screw thread and served to clamp the diaphragm between them. The compound bar magnet was held in place within the shell by means of a screw _7_ passing through the hard rubber tail cap _6_ and into the tail block _3_ of the magnet. External binding posts mounted on the tail cap, as shown, were connected by heavy leading-in wires to the terminals of the electromagnet. A casual consideration of the magnetic circuit of this instrument will show that it was inefficient, since the return path for the lines of force set up by the bar magnet was necessarily through a very long air path. Notwithstanding this, these receivers were capable of giving excellent articulation and were of marvelous delicacy of action. A very grave fault was that the magnet was supported in the shell at the end farthest removed from the diaphragm. As a result it was difficult to maintain a permanent adjustment between the pole piece and the diaphragm. One reason for this was that hard rubber and steel contract and expand under changes of temperature at very different rates, and therefore the distance between the pole piece and the diaphragm changed with changes of temperature. Another grave defect, brought about by this tying together of the permanent magnet and the shell which supported the diaphragm at the end farthest from the diaphragm, was that any mechanical shocks were thus given a good chance to alter the adjustment. [Illustration: Fig. 49. Single-Pole Receiver] Modern Receivers. Receivers of today differ from this old single-pole receiver in two radical respects. In the first place, the modern receiver is of the bi-polar type, consisting essentially of a horseshoe magnet presenting both of its poles to the diaphragm. In the second place, the modern practice is to either support all of the working parts of the receiver, _i.e._, the magnet, the coils, and the diaphragm, by an inner metallic frame entirely independent of the shell; or, if the shell is used as a part of the structure, to rigidly fasten the several parts close to the diaphragm rather than at the end farthest removed from the diaphragm. Western Electric Receiver. The standard bi-polar receiver of the Western Electric Company, in use by practically all of the Bell operating companies throughout this country and in large use abroad, is shown in Fig. 50. In this the shell is of three pieces, consisting of the barrel _1_, the ear cap _2_, and the tail cap _3_. The tail cap and the barrel are permanently fastened together to form substantially a single piece. Two permanently magnetized bar magnets _4-4_ are employed, these being clamped together at their upper ends, as shown, so as to include the soft iron block _5_ between them. The north pole of one of these magnets is clamped to the south pole of the other, so that in reality a horseshoe magnet is formed. At their lower ends, these two permanent magnets are clamped against the soft iron pole pieces _6-6_, a threaded block _7_ also being clamped rigidly between these pole pieces at this point. On the ends of the pole pieces the bobbins are wound. The whole magnet structure is secured within the shell _1_ by means of a screw thread on the block _7_ which engages a corresponding internal screw thread in the shell _1_. As a result of this construction the whole magnet structure is bound rigidly to the shell structure at a point close to the diaphragm, comparatively speaking, and as a result of this close coupling, the relation between the diaphragm and the pole piece is very much more rigid and substantial than in the case where the magnet structure and the shell were secured together at the end farthest removed from the diaphragm. [Illustration: Fig. 50. Western Electric Receiver] Although this receiver shown in Fig. 50 is the standard in use by the Bell companies throughout this country, its numbers running well into the millions, it cannot be said to be a strictly modern receiver, because of at least one rather antiquated feature. The binding posts, by which the circuit conductors are led to the coils of this instrument, are mounted on the outside of the receiver shell, as indicated, and are thus subject to danger of mechanical injury and they are also exposed to the touch of the user, so that he may, in case of the wires being charged to an abnormal potential, receive a shock. Probably a more serious feature than either one of these is that the terminals of the flexible cords which attach to these binding posts are attached outside of the receiver shell, and are therefore exposed to the wear and tear of use, rather than being protected as they should be within the shell. Notwithstanding this undesirable feature, this receiver is a very efficient one and is excellently constructed. [Illustration: Fig. 51. Kellogg Receiver] Kellogg Receiver. In Fig. 51 is shown a bi-polar receiver with internal or concealed binding posts. This particular receiver is typical of a large number of similar kinds and is manufactured by the Kellogg Switchboard and Supply Company. Two straight permanently magnetized bar magnets _1-1_ are clamped together at their opposite ends so as to form a horseshoe magnet. At the end opposite the diaphragm these bars clamp between them a cylindrical piece of iron _2_, so as to complete the magnetic circuit at the end. At the end nearest the diaphragm they clamp between them the ends of the soft iron pole pieces _3-3_, and also a block of composite metal _4_ having a large circular flange _4'_ which serves as a means for supporting the magnet structure within the shell. The screws by means of which the disk _4'_ is clamped to the shouldered seat in the shell do not enter the shell directly, but rather enter screw-threaded brass blocks which are moulded into the structure of the shell. It is seen from this construction that the diaphragm and the pole pieces and the magnet structure itself are all rigidly secured together through the medium of the shell at a point as close as possible to the diaphragm. Between the magnets _1-1_ there is clamped an insulating block _5_, to which are fastened the terminal plates _6_, one on each side of the receiver. These terminal plates are thoroughly insulated from the magnets themselves and from all other metallic parts by means of sheets of fiber, as indicated by the heavy black lines. On these plates _6_ are carried the binding posts for the receiver cord terminals. A long tongue extends from each of the plates _6_ through a hole in the disk _4'_, into the coil chamber of the receiver, at which point the terminal of the magnet winding is secured to it. This tongue is insulated from the disk _4'_, where it passes through it, by means of insulating bushing, as shown. The other terminal of the magnet coils is brought out to the other plate _6_ by means of a similar tongue on the other side. In order that the receiver terminals proper may not be subjected to any strain in case the receiver is dropped and its weight caught on the receiver cord, a strain loop is formed as a continuation of the braided covering of the receiver cord, and this is tied to the permanent magnet structure, as shown. By making this strain loop short, it is obvious that whatever pull the cord receives will not be taken by the cord conductors leading to the binding posts or by the binding posts or the cord terminals themselves. A number of other manufacturers have gone even a step further than this in securing permanency of adjustment between the receiver diaphragm and pole pieces. They have done this by not depending at all on the hard rubber shell as a part of the structure, but by enclosing the magnet coil in a cup of metal upon which the diaphragm is mounted, so that the permanency of relation between the diaphragm and the pole pieces is dependent only upon the metallic structure and not at all upon the less durable shell. Direct-Current Receiver. Until about the middle of the year 1909, it was the universal practice to employ permanent magnets for giving the initial polarization to the magnet cores of telephone receivers. This is still done, and necessarily so, in receivers employed in connection with magneto telephones. In common-battery systems, however, where the direct transmitter current is fed from the central office to the local stations, it has been found that this current which must flow at any rate through the line may be made to serve the additional purpose of energizing the receiver magnets so as to give them the necessary initial polarity. A type of receiver has come into wide use as a result, which is commonly called the _direct-current receiver_, deriving its name from the fact that it employs the direct current that is flowing in the common-battery line to magnetize the receiver cores. The Automatic Electric Company, of Chicago, was probably the first company to adopt this form of receiver as its standard type. Their receiver is shown in cross-section in Fig. 52, and a photograph of the same instrument partially disassembled is given in Fig. 53. The most noticeable thing about the construction of this receiver is the absence of permanent magnets. The entire working parts are contained within the brass cup _1_, which serves not only as a container for the magnet, but also as a seat for the diaphragm. This receiver is therefore illustrative of the type mentioned above, wherein the relation between the diaphragm and the pole pieces is not dependent upon any connection through the shell. [Illustration: Fig. 52. Automatic Electric Company Direct-Current Receiver] [Illustration: Fig. 53. Automatic Electric Company Direct-Current Receiver] The coil of this instrument consists of a single cylindrical spool _2_, mounted on a cylindrical core. This bobbin lies within a soft iron-punching _3_, the form of which is most clearly shown in Fig. 53, and this punching affords a return path to the diaphragm for the lines of force set up in the magnet core. Obviously a magnetizing current passing through the winding of the coil will cause the end of the core toward the diaphragm to be polarized, say positively, while the end of the enclosing shell will be polarized in the other polarity, negatively. Both poles of the magnet are therefore presented to the diaphragm and the only air gap in the magnetic circuit is that between the diaphragm and these poles. The magnetic circuit is therefore one of great efficiency, since it consists almost entirely of iron, the only air gap being that across which the attraction of the diaphragm is to take place. The action of this receiver will be understood when it is stated that in common-battery practice, as will be shown in later chapters, a steady current flows over the line for energizing the transmitter. On this current is superposed the incoming voice currents from a distant station. The steady current flowing in the line will, in the case of this receiver, pass through the magnet winding and establish a normal magnetic field in the same way as if a permanent magnet were employed. The superposed incoming voice currents will then be able to vary this magnetic field in exactly the same way as in the ordinary receiver. An astonishing feature of this recent development of the so-called direct-current receiver is that it did not come into use until after about twenty years of common-battery practice. There is nothing new in the principles involved, as all of them were already understood and some of them were employed by Bell in his original telephone; in fact, the idea had been advanced time and again, and thrown aside as not being worth consideration. This is an illustration of a frequent occurrence in the development of almost any rapidly growing art. Ideas that are discarded as worthless in the early stages of the art are finally picked up and made use of. The reason for this is that in some cases the ideas come in advance of the art, or they are proposed before the art is ready to use them. In other cases the idea as originally proposed lacked some small but essential detail, or, as is more often the case, the experimenter in the early days did not have sufficient skill or knowledge to make it fit the requirements as he saw them. Monarch Receiver. The receiver of the Automatic Electric Company just discussed employs but a single electromagnet by which the initial magnetization of the cores and also the variable magnetization necessary for speech reproduction is secured. The problem of the direct-current receiver has been attacked in another way by Ernest E. Yaxley, of the Monarch Telephone Manufacturing Company, with the result shown in Fig. 54. The construction in this case is not unlike that of an ordinary permanent-magnet receiver, except that in the place of the permanent magnets two soft iron cores _1-1_ are employed. On these are wound two long bobbins of insulated wire so that the direct current flowing over the telephone line will pass through these and magnetize the cores to the same degree and for the same purpose as in the case of permanent magnets. These soft iron magnet cores _1-1_ continue to a point near the coil chamber, where they join the two soft iron pole pieces _2-2_, upon which the ordinary voice-current coils are wound. The two long coils _4-4_, which may be termed the direct-current coils, are of somewhat lower resistance than the two voice-current coils _3-3_. They are, however, by virtue of their greater number of turns and the greater amount of iron that is included in their cores, of much higher impedance than the voice-current coils _3-3_. These two sets of coils _4-4_ and _3-3_ are connected in multiple. As a result of their lower ohmic resistance the coils _4-4_ will take a greater amount of the steady current which comes over the line, and therefore the greater proportion of the steady current will be employed in magnetizing the bar magnets. On account of their higher impedance to alternating currents, however, nearly all of the voice currents which are superposed on the steady currents, flowing in the line will pass through the voice-current coils _3-3_, and, being near the diaphragm, these currents will so vary the steady magnetism in the cores _2-2_ as to produce the necessary vibration of the diaphragm. [Illustration: Fig. 54. Monarch Direct-Current Receiver] This receiver, like the one of the Automatic Electric Company, does not rely on the shell in any respect to maintain the permanency of relation between the pole pieces and the diaphragm. The cup _5_, which is of pressed brass, contains the voice-current coils and also acts as a seat for the diaphragm. The entire working parts of this receiver may be removed by merely unscrewing the ear piece from the hard rubber shell, thus permitting the whole works to be withdrawn in an obvious manner. Dean Receiver. Of such decided novelty as to be almost revolutionary in character is the receiver recently put on the market by the Dean Electric Company and shown in Fig. 55. This receiver is of the direct-current type and employs but a single cylindrical bobbin of wire. The core of this bobbin and the return path for the magnetic lines of force set up in it are composed of soft iron punchings of substantially =E= shape. These punchings are laid together so as to form a laminated soft-iron field, the limbs of which are about square in cross-section. The coil is wound on the center portion of this _E_ as a core, the core being, as stated, approximately square in cross-section. The general form of magnetic circuit in this instrument is therefore similar to that of the Automatic Electric Company's receiver, shown in Figs. 52 and 53, but the core is laminated instead of being solid as in that instrument. [Illustration: Fig. 55. Dean Steel Shell Receiver] The most unusual feature of this Dean receiver is that the use of hard rubber or composition does not enter into the formation of the shell, but instead a shell composed entirely of steel stampings has been substituted therefor. The main portion of this shell is the barrel _1_. Great skill has evidently been exercised in the forming of this by the cold-drawn process, it presenting neither seams nor welds. The ear piece _2_ is also formed of steel of about the same gauge as the barrel _1_. Instead of screw-threading the steel parts, so that they would directly engage each other, the ingenious device has been employed of swaging a brass ring _3_ in the barrel portion and a similar brass ring _4_ in the ear cap portion, these two being slotted and keyed, as shown at _8_, so as to prevent their turning in their respective seats. The ring _3_ is provided with an external screw thread and the ring _4_ with an internal screw thread, so that the receiver cap is screwed on to the barrel in the same way as in the ordinary rubber shell. By the employment of these brass screw-threaded rings, the rusting together of the parts so that they could not be separated when required--a difficulty heretofore encountered in steel construction of similar parts--has been remedied. [Illustration: Fig. 56. Working Parts of Dean Receiver] The entire working parts of this receiver are contained within the cup _5_, the edge of which is flanged outwardly to afford a seat for the diaphragm. The diaphragm is locked in place on the shell by a screw-threaded ring _6_, as is clearly indicated. A ring _7_ of insulating material is seated within the enlarged portion of the barrel _1_, and against this the flange of the cup _5_ rests and is held in place by the cap _2_ when it is screwed home. The working parts of this receiver partially disassembled are shown in Fig. 56, which gives a clear idea of some of the features not clearly illustrated in Fig. 55. It cannot be denied that one of the principal items of maintenance of subscribers' station equipment has been due to the breakage of receiver shells. The users frequently allow their receiver to fall and strike heavily against the wall or floor, thus not only subjecting the cords to great strain, but sometimes cracking or entirely breaking the receiver shell. The innovation thus proposed by the Dean Company of making the entire receiver shell of steel is of great interest. The shell, as will be seen, is entirely insulated from the circuit of the receiver so that no contact exists by which a user could receive a shock. The shell is enameled inside and out with a heavy black insulating enamel baked on, and said to be of great durability. How this enamel will wear remains to be seen. The insulation of the interior portions of the receiver is further guarded by providing a lining of fiber within the shell at all points where it seems possible that a cross could occur between some of the working parts and the metal of the shell. This type of receiver has not been on the market long enough to draw definite conclusions, based on experience in use, as to what its permanent performance will be. Thus far in this chapter only those receivers which are commonly called _hand receivers_ have been discussed. These are the receivers that are ordinarily employed by the general public. [Illustration: Fig. 57. Operator's Receiver] Operator's Receiver. At the central office in telephone exchanges the operators are provided with receivers in order that they may communicate with the subscribers or with other operators. In order that they may have both of their hands free to set up and take down the connections and to perform all of the switching operations required, a special form of receiver is employed for this purpose, which is worn as a part of a head-gear and is commonly termed a _head receiver_. These are necessarily of very light construction, in order not to be burdensome to the operators, and obviously they must be efficient. They are ordinarily held in place at the ear by a metallic head band fitting over the head of the operator. [Illustration: GRANT AVENUE OFFICE OF HOME TELEPHONE COMPANY, SAN FRANCISCO, CAL. A Type of Central-Office Buildings in Down-Town Districts of Large Cities.] Such a receiver is shown in cross-section in Fig. 57, and completely assembled with its head band in Fig. 58. Referring to Fig. 57 the shell _1_ of the receiver is of aluminum and the magnets are formed of steel rings _2_, cross-magnetized so as to present a north pole on one side of the ring and a south pole on the other. The two L-shaped pole pieces _3_ are secured by screws to the poles of these ring magnets, and these pole pieces carry the magnet coils, as is clearly indicated. These poles are presented to a soft iron diaphragm in exactly the same way as in the larger hand receivers, the diaphragm being clamped in place by a hard rubber ear piece, as shown. The head bands are frequently of steel covered with leather. They have assumed numerous forms, but the general form shown in Fig. 58 is the one commonly adopted. [Illustration: Fig. 58. Operator's Receiver and Cord] [Illustration: Fig. 59. Receiver Symbols] Conventional Symbols. The usual diagrammatic symbols for hand and head receivers are shown in Fig. 59. They are self-explanatory. The symbol at the left in this figure, showing the general outline of the receiver, is the one most commonly used where any sort of a receiver is to be indicated in a circuit diagram, but where it becomes desirable to indicate in the diagram the actual connections with the coil or coils of the receiver, the symbol shown at the right is to be preferred, and obviously it may be modified as to number of windings and form of core as desired. CHAPTER VII PRIMARY CELLS Galvani, an Italian physician, discovered, in 1786, that a current of electricity could be produced by chemical action. In 1800, Volta, a physicist, also an Italian, threw further light on Galvani's discovery and produced what we know as the _voltaic_, or _galvanic_, cell. In honor of these two discoverers we have the words volt, galvanic, and the various words and terms derived therefrom. Simple Voltaic Cell. A very simple voltaic cell may be made by placing two plates, one of copper and one of zinc, in a glass vessel partly filled with dilute sulphuric acid, as shown in Fig. 60. When the two plates are not connected by a wire or other conductor, experiment shows that the copper plate bears a positive charge with respect to the zinc plate, and the zinc plate bears a negative charge with respect to the copper. When the two plates are connected by a wire, a current flows from the copper to the zinc plate through the metallic path of the wire, just as is to be expected when any conductor of relatively high electrical potential is joined to one of relatively low electrical potential. Ordinarily, when one charged body is connected to another of different potential, the resulting current is of but momentary duration, due to the redistribution of the charges and consequent equalization of potential. In the case of the simple cell, however, the current is continuous, showing that some action is maintaining the charges on the two plates and therefore maintaining the difference of potential between them. The energy of this current is derived from the chemical action of the acid on the zinc. The cell is in reality a sort of a zinc-burning furnace. In the action of the cell, when the two plates are joined by a wire, it may be noticed that the zinc plate is consumed and that bubbles of hydrogen gas are formed on the surface of the copper plate. _Theory_. Just why or how chemical action in a voltaic cell results in the production of a negative charge on the consumed plate is not known. Modern theory has it that when an acid is diluted in water the molecules of the acid are split up or _dissociated_ into two oppositely charged atoms, or groups of atoms, one bearing a positive charge and the other a negative charge of electricity. Such charged atoms or groups of atoms are called _ions_. This separation of the molecules of a chemical compound into positively and negatively charged ions is called _dissociation_. Thus, in the simple cell under consideration the sulphuric acid, by dissociation, splits up into hydrogen ions bearing positive charges, and SO_{4} ions bearing negative charges. The solution as a whole is neutral in potential, having an equal number of equal and opposite charges. [Illustration: Fig. 60. Simple Voltaic Cell] It is known that when a metal is being dissolved by an acid, each atom of the metal which is torn off by the solution leaves the metal as a positively charged ion. The carrying away of positive charges from a hitherto neutral body leaves that body with a negative charge. Hence the zinc, or _consumed_ plate, becomes negatively charged. In the chemical attack of the sulphuric acid on the zinc, the positive hydrogen ions are liberated, due to the affinity of the negative SO_{4} ions for the positive zinc ions, this resulting in the formation of zinc sulphate in the solution. Now the solution itself becomes positively charged, due to the positive charges leaving the zinc plate with the zinc ions, and the free positively charged hydrogen ions liberated in the solution as just described are repelled to the copper plate, carrying their positive charges thereto. Hence the copper plate, or the _unconsumed_ plate, becomes positively charged and also coated with hydrogen bubbles. The plates or electrodes of a voltaic cell need not consist of zinc and copper, nor need the fluid, called the _electrolyte_, be of sulphuric acid; any two dissimilar elements immersed in an electrolyte that attacks one of them more readily than the other will form a voltaic cell. In every such cell it will be found that one of the plates is consumed, and that on the other plate some element is deposited, this element being sometimes a gas and sometimes a solid. The plate which is consumed is always the negative plate, and the one on which the element is deposited is always the positive, the current through the connecting wire always being, therefore, from the unconsumed to the consumed plate. Thus, in the simple copper-zinc cell just considered, the zinc is consumed, the element hydrogen is deposited on the copper, and the current flow through the external circuit is from the copper to the zinc. The positive charges, leaving the zinc, or consumed, plate, and passing through the electrolyte to the copper, or unconsumed, plate, constitute in effect a current of electricity flowing within the electrolyte. The current within the cell passes, therefore, from the zinc plate to the copper plate. The zinc is, therefore, said to be positive with respect to the copper. _Difference of Potential._ The amount of electromotive force, that is generated between two dissimilar elements immersed in an electrolyte is different for different pairs of elements and for different electrolytes. For a given electrolyte each element bears a certain relation to another; _i.e._, they are either electro-positive or electro-negative relative to each other. In the following list a group of elements are arranged with respect to the potentials which they assume with respect to each other with dilute sulphuric acid as the electrolyte. The most electro-positive elements are at the top and the most electro-negative at the bottom. +Sodium Lead Copper Magnesium Iron Silver Zinc Nickel Gold Cadmium Bismuth Platinum Tin Antimony -Graphite (Carbon) Any two elements selected from this list and immersed in dilute sulphuric acid will form a voltaic cell, the amount of difference of potential, or electromotive force, depending on the distance apart in this series of the two elements chosen. The current within the cell will always flow from the one nearest the top of the list to the one nearest the bottom, _i.e._, from the most electro-positive to the most electro-negative; and, therefore, the current in the wire joining the two plates will flow from the one lowest down in the list to the one highest up. From this series it is easy to see why zinc and copper, and also zinc and carbon, are often chosen as elements of voltaic cells. They are widely separated in the series and comparatively cheap. This series may not be taken as correct for all electrolytes, for different electrolytes alter somewhat the order of the elements in the series. Thus, if two plates, one of iron and the other of copper, are immersed in dilute sulphuric acid, a current is set up which proceeds through the liquid from the iron to the copper; but, if the plates after being carefully washed are placed in a solution of potassium sulphide, a current is produced in the opposite direction. The copper is now the positive element. Table II shows the electrical deportment of the principal metals in three different liquids. It is arranged like the preceding one, each metal being electro-positive to any one lower in the list. TABLE II Behavior of Metals in Different Electrolytes +------------------+-------------------+--------------------+ | CAUSTIC POTASH | HYDROCHLORIC ACID | POTASSIUM SULPHIDE | +------------------+-------------------+--------------------+ | + Zinc | + Zinc | + Zinc | | Tin | Cadmium | Copper | | Cadmium | Tin | Cadmium | | Antimony | Lead | Tin | | Lead | Iron | Silver | | Bismuth | Copper | Antimony | | Iron | Bismuth | Lead | | Copper | Nickel | Bismuth | | Nickel | Silver | Nickel | | - Silver | - Antimony | - Iron | +------------------+-------------------+--------------------+ It is important to remember that in all cells, no matter what elements or what electrolyte are used, the electrode _which is consumed_ is the one that becomes _negatively charged_ and its terminal, therefore, becomes the _negative terminal_ or _pole_, while the electrode _which is not consumed_ is the one that becomes _positively charged_, and its terminal is, therefore, the _positive terminal_ or _pole of the cell_. However, because the current in the electrolyte flows from the _consumed_ plate to the _unconsumed_ plate, the consumed plate is called the _positive_ plate and the unconsumed, the _negative_. This is likely to become confusing, but if one remembers that the _active_ plate is the _positive_ plate, because it sends forth _positive_ ions in the electrolyte, and, therefore, itself becomes _negatively_ charged, one will have the proper basis always to determine the direction of the current flow, which is the important thing. _Polarization._ If the simple cell already described have its terminals connected by a wire for some time, it will be found that the current rapidly weakens until it ceases to be manifest. This weakening results from two causes: first, the hydrogen gas which is liberated in the action of the cell is deposited in a layer on the copper plate, thereby covering the plate and reducing the area of contact with the liquid. This increases the internal resistance of the cell, since hydrogen is a non-conductor. Second, the plate so covered becomes in effect a hydrogen electrode, and hydrogen stands high as an electro-positive element. There is, therefore, actual reduction in the electromotive force of the cell, as well as an increase in internal resistance. This phenomenon is known as polarization, and in commercial cells means must be taken to prevent such action as far as possible. The means by which polarization of cells is prevented or reduced in practice may be divided into three general classes: First--_mechanical means_. If the hydrogen bubbles be simply brushed away from the surface of the electrode the resistance and the counter polarity which they cause will be diminished. The same result may be secured if air be blown into the solution through a tube, or if the liquid be kept agitated. If the surface of the electrode be roughened or covered with points, the bubbles collect more freely at the points and are more quickly carried away to the surface of the liquid. These means are, however, hardly practical except in cells for laboratory use. Second--_chemical means_. If a highly oxidizing substance be added to the electrolyte, it will destroy the hydrogen bubbles by combining with them while they are in a nascent state, and this will prevent the increase in internal resistance and the opposing electromotive force. Such substances are bichromate of potash, nitric acid, and chlorine, and are largely used. Third--_electro-chemical means_. Double cells, arranged to separate the elements and liquids by means of porous partitions or by gravity, may be so arranged that solid copper is liberated instead of hydrogen at a point where the current leaves the liquid, thereby entirely obviating polarization. This method also is largely used. _Local Action._ When a simple cell stands idle, _i.e._, with its circuit open, small hydrogen bubbles may be noticed rising from the zinc electrode instead of from copper, as is the case where the circuit is closed. This is due to impurities in the zinc plate, such as particles of iron, tin, arsenic, carbon, etc. Each of these particles acts with the surrounding zinc just as might be expected of any pair of dissimilar elements opposed to each other in an electrolyte; in other words, they constitute small voltaic cells. Local currents, therefore, are generated, circulating between the two adjacent metals, and, as a result, the zinc plate and the electrolyte are needlessly wasted and the general condition of the cell is impaired. This is called _local action_. _Amalgamated Zincs._ Local action might be prevented by the use of chemically pure zinc, but this, on account of its expense, cannot be employed commercially. Local action, however, may be overcome to a great extent by amalgamating the zinc, _i.e._, coating it with mercury. The iron particles or other impurities do not dissolve in the mercury, as does the zinc, but they float to the surface, whence the hydrogen bubbles which may form speedily carry them off, and, in other cases, the impurities fall to the bottom of the cell. As the zinc in the pasty amalgam dissolves in the acid, the film of mercury unites with fresh zinc, and so always presents a clear, bright, homogeneous surface to the action of the electrolyte. The process of amalgamating the zinc may be performed by dipping it in a solution composed of Nitric Acid 1 lb. Muriatic Acid 2 lbs. Mercury 8 oz. The acids should be first mixed and then the mercury slowly added until dissolved. Clean the zinc with lye and then dip it in the solution for a second or two. Rinse in clean water and rub with a brush. Another method of amalgamating zincs is to clean them by dipping them in dilute sulphuric acid and then in mercury, allowing the surplus to drain off. Commercial zincs, for use in voltaic cells as now manufactured, usually have about 4 per cent of mercury added to the molten zinc before casting into the form of plates or rods. Series and Multiple Connections. When a number of voltaic cells are joined in series, the positive pole of one being connected to the negative pole of the next one, and so on throughout the series, the _electromotive forces_ of all the cells are added, and the electromotive force of the group, therefore, becomes the sum of the electromotive forces of the component cells. The currents through all the cells in this case will be equal to that of one cell. If the cells be joined in multiple, the positive poles all being connected by one wire and the negative poles by another, then the _currents_ of all the cells will be added while the electromotive force of the combination remains the same as that of a single cell, assuming all the cells to be alike in electromotive force. Obviously combinations of these two arrangements may be made, as by forming strings of cells connected in series, and connecting the strings in multiple or parallel. The term battery is frequently applied to a single voltaic cell, but this term is more properly used to designate a plurality of cells joined together in series, or in multiple, or in series multiple so as to combine their actions in causing current to flow through an external circuit. We may therefore refer to a battery of so many cells. It has, however, become common, though technically improper, to refer to a single cell as a battery, so that the term battery, as indicating necessarily more than one cell, has largely lost its significance. Cells may be of two types, primary and secondary. Primary cells are those consisting of electrodes of dissimilar elements which, when placed in an electrolyte, become immediately ready for action. Secondary cells, commonly called _storage cells_ and _accumulators_, consist always of two inert plates of metal, or metallic oxide, immersed in an electrolyte which is incapable of acting on either of them until a current has first been passed through the electrolyte from one plate to the other. On the passage of a current in this way, the decomposition of the electrolyte is effected and the composition of the plates is so changed that one of them becomes electro-positive and the other electro-negative. The cell is then, when the _charging_ current ceases, capable of acting as a voltaic cell. This chapter is devoted to the primary cell or battery alone. Types of Primary Cells. Primary cells may be divided into two general classes: first, those adapted to furnish constant current; and second, those adapted to furnish only intermittent currents. The difference between cells in this respect rests largely in the means employed for preventing or lessening polarization. Obviously in a cell in which polarization is entirely prevented the current may be allowed to flow constantly until the cell is completely exhausted; that is, until the zinc is all eaten up or until the hydrogen is exhausted from the electrolyte or both. On the other hand some cells are so constituted that polarization takes place faster than the means intended to prevent it can act. In other words, the polarization gradually gains on the preventive means and so gradually reduces the current by increasing the resistance of the cell and lowering its electromotive force. In cells of this kind, however, the arrangement is such that if the cell is allowed to rest, that is, if the external circuit is opened, the depolarizing agency will gradually act to remove the hydrogen from the unattacked electrode and thus place the cell in good condition for use again. Of these two types of primary cells the intermittent-current cell is of far greater use in telephony than the constant-current cell. This is because the use of primary batteries in telephony is, in the great majority of cases, intermittent, and for that reason a cell which will give a strong current for a few minutes and which after such use will regain practically all of its initial strength and be ready for use again, is more desirable than one which will give a weaker current continuously throughout a long period of time. Since the cells which are adapted to give constant current are commonly used in connection with circuits that are continuously closed, they are called _closed-circuit cells_. The other cells, which are better adapted for intermittent current, are commonly used on circuits which stand open most of the time and are closed only occasionally when their current is desired. For this reason these are termed _open-circuit cells_. _Open-Circuit Cells_. LeClanché Cell:--By far the most important primary cell for telephone work is the so-called LeClanché cell. This assumes a large variety of forms, but always employs zinc as the negatively charged element, carbon as the positively charged element, and a solution of sal ammoniac as the electrolyte. This cell employs a chemical method of taking care of polarization, the depolarizing agent being peroxide of manganese, which is closely associated with the carbon element. The original form of the LeClanché cell, a form in which it was very largely used up to within a short time ago, is shown in Fig. 61. In this the carbon element is placed within a cylindrical jar of porous clay, the walls of this jar being of such consistency as to allow moisture slowly to permeate through it. Within this porous cup, as it is called, a plate or disk of carbon is placed, and around this the depolarizing agent, consisting of black oxide of manganese. This is usually mixed with, broken carbon, so as to increase the effective area of the carbon element in contact with the depolarizing agent, and also to reduce the total internal resistance of the cell. The zinc electrode usually consisted merely in a rod of zinc, as shown, with a suitable terminal at its upper end. [Illustration: Fig. 61. LeClanché Cell] The chemical action taking place within the LeClanché cell is, briefly, as follows: Sal ammoniac is chemically known as chloride of ammonium and is a combination of chlorine and ammonia. In the action which is assumed to accompany the passage of current in this cell, the sal ammoniac is decomposed, the chlorine leaving the ammonia to unite with an atom of the zinc plate, forming chloride of zinc and setting free ammonia and hydrogen. The ammonia is immediately dissolved in the water of the cell, and the hydrogen enters the porous cup and would speedily polarize the cell by adhering to the carbon plate but for the fact that it encounters the peroxide of manganese. This material is exceedingly rich in oxygen and it therefore readily gives up a part of its oxygen, which forms water by combination with the already liberated hydrogen and leaves what is termed a _sesquioxide_ of manganese. This absorption or combination of the hydrogen prevents immediate polarization, but hydrogen is evolved during the operation of the cell more rapidly than it can combine with[typo was 'wth'] the oxygen of the manganese, thereby leading to polarization more rapidly than the depolarizer can prevent it when the cell is heavily worked. When, however, the cell is left with its external circuit open for a time, depolarization ensues by the gradual combination of the hydrogen with the oxygen of the peroxide of manganese, and as a result the cell recuperates and in a short time attains its normal electromotive force. The electromotive force of this cell when new is about 1.47 volts. The internal resistance of the cell of the type shown in Fig. 61 is approximately 1 ohm, ordinarily less rather than more. A more recent form of LeClanché cell is shown in cross-section in Fig. 62. This uses practically the same materials and has the same chemical action as the old disk LeClanché cell shown in Fig. 61. It dispenses, however, with the porous cup and instead employs a carbon electrode, which in itself forms a cup for the depolarizing agent. [Illustration: Fig. 62. Carbon Cylinder LeClanché Cell] The carbon electrode is in the form of a corrugated hollow cylinder which engages by means of an internal screw thread a corresponding screw thread on the outer side of the carbon cover. Within this cylinder is contained a mixture of broken carbon and peroxide of manganese. The zinc electrode is in the form of a hollow cylinder almost surrounding the carbon electrode and separated therefrom by means of heavy rubber bands stretched around the carbon. The rod, forming the terminal of the zinc, passes through a porcelain bushing on the cover plate to obviate short circuits. This type of cell has an electromotive force of about 1.55 volts and recuperates very quickly after severe use. It also has considerably lower internal resistance than the type of LeClanché cell employing a porous cup, and, therefore, is capable of generating a considerably larger current. Cells of this general type have assumed a variety of forms. In some the carbon electrode, together with the broken carbon and peroxide of manganese, were packed into a canvas bag which was suspended in the electrolyte and usually surrounded by the zinc electrode. In other forms the carbon electrode has moulded with it the manganese depolarizer. In order to prevent the salts within the cell from creeping over the edge of the containing glass jar and also over the upper portion of the carbon electrode, it is common practice to immerse the upper end of the carbon element and also the upper edge of the glass jar in hot paraffin. In setting up the LeClanché cell, place not more than four ounces of white sal ammoniac in the jar, fill the jar one-third full of water, and stir until the sal ammoniac is all dissolved. Then put the carbon and zinc elements in place. A little water poured in the vent hole of the porous jar or carbon cylinder will tend to hasten the action. An excess of sal ammoniac should not be used, as a saturated solution tends to deposit crystals on the zinc; on the other hand, the solution should not be allowed to become too weak, as in that case the chloride of zinc will form on the zinc. Both of these causes materially increase the resistance of the cell. A great advantage of the LeClanché cell is that when not in use there is but little material waste. It contains no highly corrosive chemicals. Such cells require little attention, and the addition of water now and then to replace the loss due to evaporation is about all that is required until the elements become exhausted. They give a relatively high electromotive force and have a moderately low internal resistance, so that they are capable of giving rather large currents for short intervals of time. If properly made, they recuperate quickly after polarization due to heavy use. _Dry Cell_. All the forms of cells so far considered may be quite properly termed _wet cells_ because of the fact that a free liquid electrolyte is used. This term is employed in contradistinction to the later developed cell, commonly termed the _dry cell_. This term "dry cell" is in some respects a misnomer, since it is not dry and if it were dry it would not work. It is essential to the operation of these cells that they shall be moist within, and when such moisture is dissipated the cell is no longer usable, as there is no further useful chemical action. The dry cells are all of the LeClanché type, the liquid electrolyte of that type being replaced by a semi-solid substance that is capable of retaining moisture for a considerable period. As in the ordinary wet LeClanché cell, the electrodes are of carbon and zinc, the zinc element being in the form of a cylindrical cup and forming the retaining vessel of the cell, while the carbon element is in the form of a rod or plate and occupies a central position with regard to the zinc, being held out of contact with the zinc, however, at all points. A cross-section of an excellent form of dry cell is shown in Fig. 63. The outer casing is of zinc, formed in the shape of a cylindrical cup, and serves not only as the retaining vessel, but as the negatively charged electrode. The outer surface of the zinc is completely covered on its sides and bottom with heavy pasteboard so as to insulate it from bodies with which it may come in contact, and particularly from the zinc cups of other cells used in the same battery. The positively charged electrode is a carbon rod corrugated longitudinally, as shown, in order to obtain greater surface. This rod is held in the center of the zinc cup out of contact therewith, and the intervening space is filled with a mixture of peroxide of manganese, powdered carbon, and sal ammoniac. Several thicknesses of blotting paper constitute a lining for the inner portion of the zinc electrode and serve to prevent the manganese mixture from coming directly into contact therewith. The cell is sealed with pitch, which is placed on a layer of sand and sawdust mixed in about equal parts. [Illustration: Fig. 63. Dry Cell] The electrolyte in such cells varies largely as to quantities and proportions of the materials employed in various types of cells, and also varies in the method in which the elements are introduced into the container. The following list and approximate proportions of material will serve as a fair example of the filling mixture in well-known types of cells. Manganese dioxide 45 per cent Carbon or graphite, or both 45 per cent Sal ammoniac 7 per cent Zinc chloride 3 per cent Water is added to the above and a sufficient amount of mixture is taken for each cell to fill the zinc cup about seven-eighths full when the carbon is in place. The most suitable quantity of water depends upon the original dryness and fineness of material and upon the quality of the paper lining. In some forms of dry batteries, starch or other paste is added to improve the contact of the electrolyte with the zinc and promote a more even distribution of action throughout the electrolyte. Mercury, too, is often added to effect amalgamation of the zinc. As in the ordinary wet type of LeClanché cell, the purpose of the manganese is to act as a depolarizer; the carbon or graphite being added to give conductivity to the manganese and to form a large electrode surface. It is important that the sal ammoniac, which is the active agent of the cell, should be free from lumps in order to mix properly with the manganese and carbon. A small local action takes place in the dry cell, caused by the dissimilar metals necessarily employed in soldering up the zinc cup and in soldering the terminal rod of zinc to the zinc cup proper. This action, however, is slight in the better grades of cells. As a result of this, and also of the gradual drying out of the moisture within the cell, these cells gradually deteriorate even when not in use--this is commonly called _shelf-wear_. Shelf-wear is much more serious in the very small sizes of dry cells than in the larger ones. Dry cells are made in a large number of shapes and sizes. The most useful form, however, is the ordinary cylindrical type. These are made in sizes varying from one and one-half inches high and three-quarters inch in diameter to eight inches high and three and three-quarters inches in diameter. The most used and standard size of dry cell is of cylindrical form six inches high and two and three-quarters inches in diameter. The dry cell when new and in good condition has an open-circuit voltage of from 1.5 to 1.6 volts. Perhaps 1.55 represents the usual average. A cell of the two and three-quarters by six-inch size will give throughout its useful life probably thirty ampere hours as a maximum, but this varies greatly with the condition of use and the make of cell. Its effective voltage during its useful life averages about one volt, and if during this life it gives a total discharge of thirty ampere hours, the fair energy rating of the cell will be thirty watt-hours. This may not be taken as an accurate figure, however, as the watt-hour capacity of a cell depends very largely, not only on the make of the cell, but on the rate of its discharge. An examination of Fig. 63 shows that the dry cell has all of the essential elements of the LeClanché cell. The materials of which the electrodes are made are the same and the porous cup of the disk LeClanché cell is represented in the dry cell by the blotting-paper cylinder, which separates the zinc from the carbon electrode. The positively charged electrode must not be considered as merely the carbon plate or rod alone, but rather the carbon rod with its surrounding mixture of peroxide of manganese and broken carbon. Such being the case, it is obvious that the separation between the electrodes is very small, while the surface presented by both electrodes is very large. As a result, the internal resistance of the cell is small and the current which it will give on a short circuit is correspondingly large. A good cell of the two and three-quarters by six-inch size will give eighteen or twenty amperes on short-circuit, when new. As the action of the cell proceeds, zinc chloride and ammonia are formed, and there being insufficient water to dissolve the ammonia, there results the formation of double chlorides of zinc and ammonium. These double chlorides are less soluble than the chlorides and finally occupy the pores of the paper lining between the electrolyte and the zinc and greatly increase the internal resistance of the cell. This increase of resistance is further contributed to by the gradual drying out of the cell as its age increases. Within the last few years dry batteries have been so perfected mechanically, chemically, and electrically that they have far greater outputs and better recuperative power than any of the other types of LeClanché batteries, while in point of convenience and economy, resulting from their small size and non-breakable, non-spillable features and low cost, they leave no room for comparison. _Closed-Circuit Cells_. Gravity-Cell:--Coming now to the consideration of closed-circuit or constant-current cells, the most important is the well-known gravity, or blue-stone, cell, devised by Daniell. It is largely used in telegraphy, and often in telephony in such cases as require a constantly flowing current of small quantity. Such a cell is shown in Fig. 64. The elements of the gravity cell are electrodes of copper and zinc. The solution in which the copper plate is immersed is primarily a solution of copper sulphate, commonly known as blue-stone, in water. The zinc plate after the cell is in action is immersed in a solution of sulphate of zinc which is formed around it. The glass jar is usually cylindrical, the standard sizes being 5 inches diameter and 7 inches deep; and also 6 inches diameter and 8 inches deep. The copper electrode is of sheet copper of the form shown, and it is partly covered with crystals of blue-stone or copper sulphate. Frequently, in later forms of cells, the copper electrode consists merely of a straight, thick, rectangular bar of copper laid horizontally, directly on top of the blue-stone crystals. In all cases a rubber-insulated wire is attached by riveting to the copper electrode, and passes up through the electrolyte to form the positive terminal. [Illustration: Fig. 64. Gravity Cell] The zinc is, as a rule, of crowfoot form, as shown, whence this cell derives the commonly applied name of _crowfoot cell_. This is essentially a two-fluid cell, for in its action zinc sulphate is formed, and this being lighter than copper sulphate rises to the top of the jar and surrounds the zinc. Gravity, therefore, serves to keep the two fluids separate. [Illustration: INTERIOR OF WAREHOUSE FOR TELEPHONE CONSTRUCTION MATERIAL] In the action of the cell, when the external circuit is closed, sulphuric acid is formed which attacks the zinc to form sulphate of zinc and to liberate hydrogen, which follows its tendency to attach itself to the copper plate. But in so doing the hydrogen necessarily passes through the solution of sulphate of copper surrounding the copper plate. The hydrogen immediately combines with the SO_{4} radical, forming therewith sulphuric acid, and liberating metallic copper. This sulphuric acid, being lighter than the copper sulphate, rises to the surface of the zinc and attacks the zinc, thus forming more sulphate of zinc. The metallic copper so formed is deposited on the copper plate, thereby keeping the surface bright and clean. Since hydrogen is thus diverted from the copper plate, polarization does not ensue. The zinc sulphate being colorless, while the copper sulphate is of a dark blue color, the separating line of the two liquids is easily distinguishable. This line is called the _blue line_ and care should be taken that it does not reach the zinc and cause a deposit of copper to be placed thereon. As has been stated, these two liquids do not mix readily, but they will eventually mingle unless the action of the cell is sufficient to use up the copper sulphate as speedily as it is dissolved. Thus it will be seen that while the cell is free from polarization and local action, there is, nevertheless, a deteriorating effect if the cell is allowed to remain long on open circuit. Therefore, it should be used when a constant current is required. Prevention of Creeping:--Much trouble has been experienced in gravity cells due to the creeping of the salts over the edge of the jar. Frequently the upper edges of the jars are coated by dipping in hot paraffin wax in the hope of preventing this. Sometimes oil is poured on top of the fluid in the jar to prevent the creeping of the salts and the evaporation of the electrolyte. The following account of experiments performed by Mr. William Reid, of Chicago, throws light on the relative advantages of these and other methods of preventing creeping. The experiment was made with gravity cells having 5-inch by 7-inch glass jars. Four cells were made up and operated in a rather dry, warm place, although perhaps under no more severe local conditions than would be found in most telephone exchanges. Cell No. 1 was a plain cell as ordinarily used. Cell No. 2 had the top of the rim of the jar treated with paraffin wax by dipping the rim to about one inch in depth in melted paraffin wax. Cell No. 3 had melted paraffin wax poured over the surface of the liquid forming a seal about 3/16 inch in thickness. After cooling, a few small holes were bored through the seal to let gases escape. Cell No. 4 had a layer of heavy paraffin oil nearly 1/2 inch in thickness (about 6 oz. being used) on top of the solutions. These cells were all run on a load of .22 to .29 amperes for 15-1/2 hours per day for thirty days, after which the following results were noted: (_a_) The plain cell, or cell No. 1, had to have 26 ounces of water added to it to replace that which had evaporated. The creeping of zinc sulphate salts was very bad. (_b_) The waxed rim cell, or cell No. 2, evaporated 26 ounces of water and the creeping of zinc sulphate salts was not prevented by the waxed rim. The wax proved of no value. (_c_) The wax sealed cell, or cell No. 3, showed practically no evaporation and only very slight creeping of zinc sulphate salts. The creeping of salts that took place was only around spots where the edges of the seal were loose from the jar. (_d_) The paraffin oil sealed cell, or cell No. 4, showed no evaporation and no creeping of salts. It was concluded by Mr. Reid from the above experiments that the wax applied to the rim of the jar is totally ineffective and has no merits. The wax seal loosens around the edges and does not totally prevent creeping of the zinc sulphate salts, although nearly so. The wax-sealed jar must have holes drilled in it to allow the gases to escape. The method is hardly commercial, as it is difficult to make a neat appearing cell, besides making it almost impossible to manipulate its contents. A coat of paraffin oil approximately 1/2 inch in thickness (about 6 ounces) gives perfect protection against evaporation and creeping of the zinc sulphate salts. The cell, having the paraffin-oil seal, had a very neat, clean appearance as compared with cells No. 1 and No. 2. It was found that the zinc could be drawn out through the oil, cleaned, and replaced with no appreciable effect on voltage or current. Setting Up:--In setting up the battery the copper electrode is first unfolded to form a cross and placed in the bottom of the jar. Enough copper sulphate, or blue-stone crystals, is then dropped into the jar to almost cover the copper. The zinc crowfoot is then hung in place, occupying a position about 4 inches above the top of the copper. Clear water is then poured in sufficient to fill the jar within about an inch of the top. If it is not required to use the cell at once, it may be placed on short circuit for a time and allowed to form its own zinc sulphate. The cell may, however, be made immediately available for use by drawing about one-half pint of a solution of zinc sulphate from a cell already in use and pouring it into the jar, or, when this is not convenient, by putting into the liquid four or five ounces of pulverized sulphate of zinc, or by adding about ten drops of sulphuric acid. When the cell is in proper working condition, one-half inch in thickness of heavy paraffin oil of good quality may be added. If the blue line gets too low, and if there is in the bottom of the cell a sufficient quantity of sulphate of copper, it may be raised by drawing off a portion of the zinc sulphate with a battery syringe and replacing this with water. If the blue line gets too high, it may be lowered by short-circuiting the cell for a time, or by the addition of more sulphate of zinc solution from another battery. If the copper sulphate becomes exhausted, it should be replenished by dropping in more crystals. Care should be taken in cold weather to maintain the temperature of the battery above 65° or 70° Fahrenheit. If below this temperature, the internal resistance of a cell increases very rapidly, so much so that even at 50° Fahrenheit the action becomes very much impaired. This follows from the facts that the resistance of a liquid decreases as its temperature rises, and that chemical action is much slower at lower temperatures. The gravity cell has a practically constant voltage of 1.08 volts. Its internal resistance is comparatively high, seldom falling below 1 ohm and often rising to 6 ohms. At best, therefore, it is only capable of producing about 1 ampere. The gravity cell is perhaps the most common type of cell wherein depolarization is affected by electro-chemical means. Fuller Cell:--A form of cell that is adapted to very heavy open-circuit work and also closed-circuit work where heavier currents are required than can be supplied by the gravity battery is the Fuller. In this the electrodes are of zinc and carbon, respectively, the zinc usually being in the form of a heavy cone and placed within a porous cup. The electrolyte of the Fuller cell is known as _electropoion fluid_, and consists of a mixture of sodium or potassium bichromate, sulphuric acid, and water. The various parts of the standard Fuller cell, as once largely employed by the various Bell operating companies, are shown in Fig. 65. In this the jar was made of flint glass, cylindrical in form, six inches in diameter and eight inches deep. It is important that a good grade of glass be used for the jar in this cell, because, on account of the nature of the electrolyte, breakage is disastrous in the effects it may produce on adjacent property. The carbon plate is rectangular in form, about four inches wide, eight and three-quarters inches long, and one-quarter inch thick. The metal terminal at the top of the carbon block is of bronze, both it and the lock nuts and bolts being nickel-plated to minimize corrosion. The upper end of the carbon block is soaked in paraffin so hot as to drive all of the moisture out of the paraffin and out of the pores of the block itself. The zinc, as is noted from the cut, is in the form of a truncated cone. It is about two and one-eighth inches in diameter at the base and two and one-half inches high. Cast into the zinc is a soft copper wire about No. 12 B. & S. gauge. This wire extends above the top of the jar so as to form a convenient terminal for the cell. The porous cup is cylindrical in form, about three inches in diameter and seven inches deep. The wooden cover is of kiln-dried white wood thoroughly coated with two coats of asphalt paint. It is provided with a slot for the carbon and a hole for the copper wire extending to the zinc. The electrolyte for this cell is made as follows: Sodium bichromate 6 oz. Sulphuric acid 17 oz. Soft water 56 oz. This solution is mixed by dissolving the bichromate of sodium in the water and then adding slowly the sulphuric acid. Potassium bichromate may be substituted for the sodium bichromate. In setting up this cell, the amalgamated zinc is placed within the porous cup, in the bottom of which are about two teaspoonfuls of mercury, the latter serving to keep the zinc well amalgamated. The porous cup is then placed in the glass jar and a sufficient quantity of the electrolyte is placed in the outer jar to come within about one and one-half inches of the top of the porous cup. About two teaspoonfuls of salt are then placed in the porous cup and sufficient soft water added to bring the level of the liquid within the porous cup even with the level of the electrolyte in the jar surrounding the cup. The carbon is then placed through the slot in the cover, and the wire from the zinc is passed through the hole in the cover provided for it, and the cover is allowed to fall in place. The cell is now ready for immediate use. The action of this cell is as follows: The sulphuric acid attacks the zinc and forms zinc sulphate, liberating hydrogen. The hydrogen attempts to pass to the carbon plate as usual, but in so doing it meets with the oxygen of the chromic acid and forms water therewith. The remainder of the chromic acid combines with the sulphuric acid to form chromium sulphate. [Illustration: Fig 65. Fuller Cell] The mercury placed in the bottom of the porous cup with the zinc keeps the zinc in a state of perpetual amalgamation. This it does by capillary action, as the mercury spreads over the entire surface of the zinc. The initial amalgamation, while not absolutely essential, helps in a measure this capillary action. In another well-known type of the Fuller battery the carbon is a hollow cylinder, surrounding the porous cup. In this type the zinc usually took the form of a long bar having a cross-shaped section, the length of this bar being sufficient to extend the entire depth of the porous cup. This type of cell has the advantage of a somewhat lower internal resistance than the standard form just described. Should the electrolyte become supersaturated by virtue of the battery being neglected or too heavily overworked, a set of secondary reactions will occur in the cell, resulting in the formation of the yellow crystals upon the carbon. This seriously affects the e.m.f. of the cell and also its internal resistance. Should this occur, some of the solution should be withdrawn and dilute sulphuric acid inserted in its place and the crystals which have formed on the carbon should be carefully washed off. Should the solution lose its orange tint and turn blue, it indicates that more bichromate of potash or bichromate of sodium is needed. This cell gives an electromotive force of 2.1 volts and a very large current when it is in good condition, since its internal resistance is low. The Fuller cell was once largely used for supplying current to telephone transmitters at subscribers' stations, where very heavy service was demanded, but the advent of the so-called common-battery systems, in some cases, and of the high-resistance transmitter, in other cases, has caused a great lessening in its use. This is fortunate as the cell is a "dirty" one to handle and is expensive to maintain. The Fuller cell still warrants attention, however, as an available source of current, which may be found useful in certain cases of emergency work, and in supplying special but temporary needs for heavier current than the LeClanché or gravity cell can furnish. Lalande Cell:--A type of cell, specially adapted to constant-current work, and sometimes used as a central source of current in very small common-battery exchanges is the so-called _copper oxide_, or _Lalande cell_, of which the Edison and the Gordon are types. In all of these the negatively charged element is of zinc, the positively charged element a mass of copper oxide, and the electrolyte a solution of caustic potash in water. In the Edison cell the copper oxide is in the form of a compressed slab which with its connecting copper support forms the electrode. In the Gordon and other cells of this type the copper oxide is contained loosely in a perforated cylinder of sheet copper. The copper oxide serves not only as an electrode, but also as a depolarizing agent, the liberated hydrogen in the electrolyte uniting with the oxygen of the copper oxide to form water, and leaving free metallic copper. On open circuit the elements are not attacked, therefore there is no waste of material while the cell is not in use. This important feature, and the fact that the internal resistance is low, make this cell well adapted for all forms of heavy open-circuit work. The fact that there is no polarizing action within the cell makes it further adaptable to heavy closed-circuit service. These cells are intended to be so proportioned that all of their parts become exhausted at once so that when the cell fails, complete renewals are necessary. Therefore, there is never a question as to which of the elements should be renewed. After the elements and solution are in place about one-fourth of an inch of heavy paraffin oil is poured upon the surface of the solution in order to prevent evaporation. This cell requires little attention and will maintain a constant e.m.f. of about two-thirds of a volt until completely exhausted. It is non-freezable at all ordinary temperatures. Its low voltage is its principal disadvantage. _Standard Cell_. Chloride of Silver Cell:--The chloride of silver cell is largely used as a standard for testing purposes. Its compactness and portability and its freedom from local action make it particularly adaptable to use in portable testing outfits where constant electromotive force and very small currents are required. [Illustration: Fig. 66. Chloride of Silver Cell] A cross-section of one form of the cell is shown in Fig. 66. Its elements are a rod of chemically-pure zinc and a rod of chloride of silver immersed in a water solution of sal ammoniac. As ordinarily constructed, the glass jar or tube is usually about 2-1/2 inches long by 1 inch in diameter. After the solution is poured in and the elements are in place the glass tube is hermetically sealed with a plug of paraffin wax. The e.m.f. of a cell of this type is 1.03 volts and the external resistance varies with the age of the cell, being about 4 ohms at first. Care should be taken not to short-circuit these cells, or use them in any but high-resistance circuits, as they have but little energy and become quickly exhausted if compelled to work in low-resistance circuits. Conventional Symbol. The conventional symbol for a cell, either of the primary or the secondary type, consists of a long thin line and a short heavy line side by side and parallel. A battery is represented by a number of pairs of such lines, as in Fig. 67. The two lines of each pair are supposed to represent the two electrodes of a cell. Where any significance is to be placed on the polarity of the cell or battery the long thin line is supposed to represent the positively charged plate and the short thick line the negatively charged plate. The number of pairs may indicate the number of cells in the battery. Frequently, however, a few pairs of such lines are employed merely for the purpose of indicating a battery without regard to its polarity or its number of cells. [Illustration: Fig. 67. Battery Symbols] In Fig. 67 the representation at _A_ is that of a battery of a number of cells connected in parallel; that at _B_ of a battery with the cells connected in series; and that at _C_ of a battery with one of its poles grounded. CHAPTER VIII MAGNETO SIGNALING APPARATUS Method of Signaling. The ordinary apparatus, by which speech is received telephonically, is not capable of making sufficiently loud sounds to attract the attention of people at a distance from the instrument. For this reason it is necessary to employ auxiliary apparatus for the purpose of signaling between stations. In central offices where an attendant is always on hand, the sense of sight is usually appealed to by the use of signals which give a visual indication, but in the case of telephone instruments for use by the public, the sense of hearing is appealed to by employing an audible rather than a visual signal. Battery Bell. The ordinary vibrating or battery bell, such as is employed for door bells, is sometimes, though not often, employed in telephony. It derives its current from primary batteries or from any direct-current source. The reason why they are not employed to a greater extent in telephony is that telephone signals usually have to be sent over lines of considerable length and the voltage that would be required to furnish current to operate such bells over such lengths of line is higher than would ordinarily be found in the batteries commonly employed in telephone work. Besides this the make-and-break contacts on which the, ordinary battery bell depends for its operation are an objectionable feature from the standpoint of maintenance. Magneto Bell. Fortunately, however, there has been developed a simpler type of electric bell, which operates on smaller currents, and which requires no make-and-break contacts whatever. This simpler form of bell is commonly known as the _polarized_, or _magneto_, bell or _ringer_. It requires for its operation, in its ordinary form, an alternating current, though in its modified forms it may be used with pulsating currents, that is, with periodically recurring impulses of current always in the same direction. Magneto Generator. In the early days of telephony there was nearly always associated with each polarized bell a magneto generator for furnishing the proper kind of current to ring such bells. Each telephone was therefore equipped, in addition to the transmitter and receiver, with a signal-receiving device in the form of a polarized bell, and with a current generator by which the user was enabled to develop his own currents of suitable kind and voltage for ringing the bells of other stations. Considering the signaling apparatus of the telephones alone, therefore, each telephone was equipped with a power plant for generating currents used by that station in signaling other stations, the prime mover being the muscles of the user applied to the turning of a crank on the side of the instrument; and also with a current-consuming device in the form of a polarized electromagnetic bell adapted to receive the currents generated at other stations and to convert a portion of their energy into audible signals. The magneto generator is about the simplest type of dynamo-electric machine, and it depends upon the same principles of operation as the much larger generators, employed in electric-lighting and street-railway power plants, for instance. Instead of developing the necessary magnetic field by means of electromagnets, as in the case of the ordinary dynamo, the field of the magneto generator is developed by permanent magnets, usually of the horseshoe form. Hence the name _magneto_. [Illustration: Fig. 68. Principles of Magneto Generator] In order to concentrate the magnetic field within the space in which the armature revolves, pole pieces of iron are so arranged in connection with the poles of the permanent magnet as to afford a substantially cylindrical space in which the armature conductors may revolve and through which practically all the magnetic lines of force set up by the permanent magnets will pass. In Fig. 68 there is shown, diagrammatically, a horseshoe magnet with such a pair of pole pieces, between which a loop of wire is adapted to rotate. The magnet _1_ is of hardened steel and permanently magnetized. The pole pieces are shown at _2_ and _3_, each being of soft iron adapted to make good magnetic contact on its flat side with the inner flat surface of the bar magnet, and being bored out so as to form a cylindrical recess between them as indicated. The direction of the magnetic lines of force set up by the bar magnet through the interpolar space is indicated by the long horizontal arrows, this flow being from the north pole (N) to the south pole (S) of the magnet. At _4_ there is shown a loop of wire supposed to revolve in the magnetic field of force on the axis _5-5_. Theory. In order to understand how currents will be generated in this loop of wire _4_, it is only necessary to remember that if a conductor is so moved as to cut across magnetic lines of force, an electromotive force will be set up in the conductor which will tend to make the current flow through it. The magnitude of the electromotive force will depend on the rate at which the conductor cuts through the lines of force, or, in other words, on the number of lines of force that are cut through by the conductor in a given unit of time. Again, the direction of the electromotive force depends on the direction of the cutting, so that if the conductor be moved in one direction across the lines of force, the electromotive force and the current will be in one direction; while if it moves in the opposite direction across the lines of force, the electromotive force and the current will be in the reverse direction. It is, evident that as the loop of wire _4_ revolves in the field of force about the axis _5-5_, the portions of the conductor parallel to the axis will cut through the lines of force, first in one direction and then in the other, thus producing electromotive forces therein, first in one direction and then in the other. Referring now to Fig. 68, and supposing that the loop _4_ is revolving in the direction of the curved arrow shown between the upper edges of the pole pieces, it will be evident that just as the loop stands in the vertical position, its horizontal members will be moving in a horizontal direction, parallel with the lines of force and, therefore, not cutting them at all. The electromotive force and the current will, therefore, be zero at this time. As the loop advances toward the position shown in dotted lines, the upper portion of the loop that is parallel with the axis will begin to cut downwardly through the lines of force, and likewise the lower portion of the loop that is parallel with the axis will begin to cut upwardly through the lines of force. This will cause electromotive forces in opposite directions to be generated in these portions of the loop, and these will tend to aid each other in causing a current to circulate in the loop in the direction shown by the arrows associated with the dotted representation of the loop. It is evident that as the motion of the loop progresses, the rate of cutting the lines of force will increase and will be a maximum when the loop reaches a horizontal position, or at that time the two portions of the loop that are parallel with the axis will be traveling at right angles to the lines of force. At this point, therefore, the electromotive force and the current will be a maximum. From this point until the loop again assumes a vertical position, the cutting of the lines of force will still be in the same direction, but at a constantly decreasing rate, until, finally, when the loop is vertical the movement of the parts of the loop that are parallel with the axis will be in the direction of the lines of force and, therefore, no cutting will take place. At this point, therefore, the electromotive force and the current in the loop again will be zero. We have seen, therefore, that in this half revolution of the loop from the time when it was in a vertical position to a time when it was again in a vertical position but upside down, the electromotive force varied from zero to a maximum and back to zero, and the current did the same. It is easy to see that, as the loop moves through the next half revolution, an exactly similar rise and fall of electromotive force and current will take place; but this will be in the opposite direction, since that portion of the loop which was going down through the lines of force is now going up, and the portion which was previously going up is now going down. The law concerning the generation of electromotive force and current in a conductor that is cutting through lines of magnetic force, may be stated in another way, when the conductor is bent into the form of a loop, as in the case under consideration: Thus, _if the number of lines of force which pass through a conducting loop be varied, electromotive forces will be generated in the loop_. This will be true whether the number of lines passing through the loop be varied by moving the loop within the field of force or by varying the field of force itself. In any case, _if the number of lines of force be increased, the current will flow in one way, and if it be diminished the current will flow in the other way_. The amount of the current will depend, other things being equal, on the rate at which the lines of force through the loop are being varied, regardless of the method by which the variation is made to take place. One revolution of the loop, therefore, results in a complete cycle of alternating current consisting of one positive followed by one negative impulse. The diagram of Fig. 68 is merely intended to illustrate the principle involved. In the practical construction of magneto generators more than one bar magnet is used, and, in addition, the conductors in the armature are so arranged as to include a great many loops of wire. Furthermore, the conductors in the armature are wound around an iron core so that the path through the armature loops or turns, may present such low reluctance to the passage of lines of force as to greatly increase the number of such lines and also to cause practically all of them to go through the loops in the armature conductor. Armature. The iron upon which the armature conductors are wound is called the _core_. The core of an ordinary armature is shown in Fig. 69. This is usually made of soft gray cast iron, turned so as to form bearing surfaces at _1_ and _2_, upon which the entire armature may rotate, and also turned so that the surfaces _3_ will be truly cylindrical with respect to the axis through the center of the shaft. The armature conductors are put on by winding the space between the two parallel faces _4_ as full of insulated wire as space will admit. One end of the armature winding is soldered to the pin _5_ and, therefore, makes contact with the frame of the generator, while the other end of the winding is soldered to the pin _6_, which engages the stud _7_, carried in an insulating bushing in a longitudinal hole in the end of the armature shaft. It is thus seen that the frame of the machine will form one terminal of the armature winding, while the insulated stud _7_ will form the other terminal. [Illustration: Fig. 69. Generator Armature] Another form of armature largely employed in recent magneto generators is illustrated in Fig. 70. In this the shaft on which the armature revolves does not form an integral part of the armature core but consists of two cylindrical studs _2_ and _3_ projecting from the centers of disks _4_ and _5_, which are screwed to the ends of the core _1_. This =H= type of armature core, as it is called, while containing somewhat more parts than the simpler type shown in Fig. 69, possesses distinct advantages in the matter of winding. By virtue of its simpler form of winding space, it is easier to insulate and easier to wind, and furthermore, since the shaft does not run through the winding space, it is capable of holding a considerably greater number of turns of wire. The ends of the armature winding are connected, one directly to the frame and the other to an insulated pin, as is shown in the illustration. [Illustration: Fig. 70. Generator Armature] [Illustration: Fig. 71. Generator Field and Armature] The method commonly employed of associating the pole pieces with each other and with the permanent magnets is shown in Fig. 71. It is very important that the space in which the armature revolves shall be truly cylindrical, and that the bearings for the armature shall be so aligned as to make the axis of rotation of the armature coincide with the axis of the cylindrical surface of the pole pieces. A rigid structure is, therefore, required and this is frequently secured, as shown in Fig. 71, by joining the two pole pieces _1_ and _2_ together by means of heavy brass rods _3_ and _4_, the rods being shouldered and their reduced ends passed through holes in flanges extending from the pole pieces, and riveted. The bearing plates in which the armature is journaled are then secured to the ends of these pole pieces, as will be shown in subsequent illustrations. This assures proper rigidity between the pole pieces and also between the pole pieces and the armature bearings. The reason why this degree of rigidity is required is that it is necessary to work with very small air gaps between the armature core and its pole pieces and unless these generators are mechanically well made they are likely to alter their adjustment and thus allow the armature faces to scrape or rub against the pole pieces. In Fig. 71 one of the permanent horseshoe magnets is shown, its ends resting in grooves on the outer faces of the pole pieces and usually clamped thereto by means of heavy iron machine screws. With this structure in mind, the theory of the magneto generator developed in connection with Fig. 68 may be carried a little further. When the armature lies in the position shown at the left of Fig. 71, so that the center position of the core is horizontal, a good path is afforded for the lines of force passing from one pole to the other. Practically all of these lines will pass through the iron of the core rather than through the air, and, therefore, practically all of them will pass through the convolutions of the armature winding. When the armature has advanced, say 45 degrees, in its rotation in the direction of the curved arrow, the lower right-hand portion of the armature flange will still lie opposite the lower face of the right-hand pole piece and the upper left-hand portion of the armature flange will still lie opposite the upper face of the left-hand pole piece. As a result there will still be a good path for the lines of force through the iron of the core and comparatively little change in the number of lines passing through the armature winding. As the corners of the armature flange pass away from the corners of the pole pieces, however, there is a sudden change in condition which may be best understood by reference to the right-hand portion of Fig. 71. The lines of force now no longer find path through the center portion of the armature core--that lying at right angles to their direction of flow. Two other paths are at this time provided through the now horizontal armature flanges which serve almost to connect the two pole pieces. The lines of force are thus shunted out of the path through the armature coils and there is a sudden decrease from a large number of lines through the turns of the winding to almost none. As the armature continues in its rotation the two paths through the flanges are broken, and the path through the center of the armature core and, therefore, through the coils themselves, is reëstablished. As a result of this consideration it will be seen that in actual practice the change in the number of lines passing through the armature winding is not of the gradual nature that would be indicated by a consideration of Fig. 68 alone, but rather, is abrupt, as the corners of the armature flanges leave the corners of the pole pieces. This abrupt change produces a sudden rise in electromotive force just at these points in the rotation, and, therefore, the electromotive force and the current curves of these magneto generators is not usually of the smooth sine-wave type but rather of a form resembling the sine wave with distinct humps added to each half cycle. [Illustration: Fig. 72. Generator with Magnets Removed] As is to be expected from any two-pole alternating generator, there is one cycle of current for each revolution of the armature. Under ordinary conditions a person is able to turn the generator handle at the rate of about two hundred revolutions a minute, and as the ratio of gearing is about five to one, this results in about one thousand revolutions per minute of the generator, and, therefore, in a current of about one thousand cycles per minute, this varying widely according to the person who is doing the turning. [Illustration: HOWARD OFFICE OF HOME TELEPHONE COMPANY, SAN FRANCISCO An All-Concrete Building Serving the District South of Market Street.] The end plates which support the bearings for the armature are usually extended upwardly, as shown in Fig. 72, so as to afford bearings for the crank shaft. The crank shaft carries a large spur gear which meshes with a pinion in the end of the armature shaft, so that the user may cause the armature to revolve rapidly. The construction shown in Fig. 72 is typical of that of a modern magneto generator, it being understood that the permanent magnets are removed for clearness of illustration. Fig. 73 is a view of a completely assembled generator such as is used for service requiring a comparatively heavy output. Other types of generators having two, three, or four permanent magnets instead of five, as shown in this figure, are also standard. [Illustration: Fig. 73. Five-Bar Generator] Referring again to Fig. 69, it will be remembered that one end of the armature winding shown diagrammatically in that figure, is terminated in the pin _5_, while the other terminates in the pin _7_. When the armature is assembled in the frame of the generator it is evident that the frame itself is in metallic connection with one end of the armature winding, since the pin _5_ is in metallic contact with the armature casting and this is in contact with the frame of the generator through the bearings. The frame of the machine is, therefore, one terminal of the generator. When the generator is assembled a spring of one form or another always rests against the terminal pin _7_ of the armature so as to form a terminal for the armature winding of such a nature as to permit the armature to rotate freely. Such spring, therefore, forms the other terminal of the generator. Automatic Shunt. Under nearly all conditions of practice it is desirable to have the generator automatically perform some switching function when it is operated. As an example, when the generator is connected so that its armature is in series in a telephone line, it is quite obvious that the presence of the resistance and the impedance of the armature winding would be objectionable if left in the circuit through which the voice currents had to pass. For this reason, what is termed an _automatic shunt_ is employed on generators designed for series work; this shunt is so arranged that it will automatically shunt or short-circuit the armature winding when it is at rest and also break this shunt when the generator is operated, so as to allow the current to pass to line. [Illustration: Fig 74. Generator Shunt Switch] A simple and much-used arrangement for this purpose is shown in Fig. 74, where _1_ is the armature; _2_ is a wire leading from the frame of the generator and forming one terminal of the generator circuit; and _3_ is a wire forming the other terminal of the generator circuit, this wire being attached to the spring _4_, which rests against the center pin of the armature so as to make contact with the opposite end of the armature winding to that which is connected with the frame. The circuit through the armature may be traced from the terminal wire _2_ through the frame; thence through the bearings to the armature _1_ and through the pin to the right-hand side of the armature winding. Continuing the circuit through the winding itself, it passes to the center pin projecting from the left-hand end of the armature shaft; thence to the spring _4_ which rests against this pin; and thence to the terminal wire _3_. Normally, this path is shunted by what is practically a short circuit, which may be traced from the terminal _2_ through the frame of the generator to the crank shaft _5_; thence to the upper end of the spring _4_ and out by the terminal wire _3_. This is the condition which ordinarily exists and which results in the removal of the resistance and the impedance on the armature winding from any circuit in which the generator is placed, as long as the generator is not operated. An arrangement is provided, however, whereby the crank shaft _5_ will be withdrawn automatically from engaging with the upper end of the spring _4_, thus breaking the shunt around the armature circuit, whenever the generator crank is turned. In order to accomplish this the crank shaft _5_ is capable of partial rotation and of slight longitudinal movement within the hub of the large gear wheel. A spring 7 usually presses the crank shaft toward the left and into engagement with the spring _4_. A pin _8_ carried by the crank shaft, rests in a V-shaped notch in the end of the hub _6_ and as a result, when the crank is turned the pin rides on the surface of this notch before the large gear wheel starts to turn, and thus moves the crank shaft _5_ to the right and breaks the contact between it and the spring _4_. Thus, as long as the generator is being operated, its armature is connected in the circuit of the line, but as soon as it becomes idle the armature is automatically short-circuited. Such devices as this are termed _automatic shunts_. In still other cases it is desirable to have the generator circuit normally open so that it will not affect in any way the electrical characteristics of the line while the line is being used for talking. In this case the arrangement is made so that the generator will automatically be placed in proper circuit relation with the line when it is operated. [Illustration: Fig. 75. Generator Cut-in Switch] A common arrangement for doing this is shown in Fig. 75, wherein the spring _1_ normally rests against the contact pin of the armature and forms one terminal of the armature circuit. The spring _2_ is adapted to form the other terminal of the armature circuit but it is normally insulated from everything. The circuit of the generator is, therefore, open between the spring _2_ and the shaft _3_, but as soon as the generator is operated the crank shaft is bodily moved to the left by means of the =V=-shaped notch in the driving collar _4_ and is thus made to engage the spring _2_. The circuit of the generator is then completed from the spring _1_ through the armature pin to the armature winding; thence to the frame of the machine and through shaft _3_ to the spring _2_. Such devices as this are largely used in connection with so-called "bridging" telephones in which the generators and bells are adapted to be connected in multiple across the line. A better arrangement for accomplishing the automatic switching on the part of the generator is to make no use of the crank shaft as a part of the conducting path as is the case in both Figs. 74 and 75, but to make the crank shaft, by its longitudinal movement, impart the necessary motion to a switch spring which, in turn, is made to engage or disengage a corresponding contact spring. An arrangement of this kind that is in common use is shown in Fig. 76. This needs no further explanation than to say that the crank shaft is provided on its end with an insulating stud _1_, against which a switching spring _2_ bears. This spring normally rests against another switch spring _3_, but when the generator crank shaft moves to the right upon the turning of the crank, the spring _2_ disengages spring _3_ and engages spring _4_, thus completing the circuit of the generator armature. It is seen that this operation accomplishes the breaking of one circuit and the making of another, a function that will be referred to later on in this work. [Illustration: Fig. 76. Generator Cut-in Switch] Pulsating Current. Sometimes it is desirable to have a generator capable of developing a pulsating current instead of an alternating current; that is, a current which will consist of impulses all in one direction rather than of impulses alternating in direction. It is obvious that this may be accomplished if the circuit of the generator be broken during each half revolution so that its circuit is completed only when current is being generated in one direction. Such an arrangement is indicated diagrammatically in Fig. 77. Instead of having one terminal of the armature winding brought out through the frame of the generator as is ordinarily done, both terminals are brought out to a commuting device carried on the end of the armature shaft. Thus, one end of the loop representing the armature winding is shown connected directly to the armature pin _1_, against which bears a spring _2_, in the usual manner. The other end of the armature winding is carried directly to a disk _3_, mounted _on_ but insulated _from_ the shaft and revolving therewith. One-half of the circumferential surface of this disk is of insulating material _4_ and a spring _5_ rests against this disk and bears alternately upon the conducting portion _3_ or the insulating portion _4_, according to the position of the armature in its revolution. It is obvious that when the generator armature is in the position shown the circuit through it is from the spring _2_ to the pin _1_; thence to one terminal of the armature loop; thence through the loop and back to the disk _3_ and out by the spring _5_. If, however, the armature were turned slightly, the spring _5_ would rest on the insulating portion _4_ and the circuit would be broken. [Illustration: Fig. 77. Pulsating-Current Commutator] [Illustration: Fig. 78. Generator Symbols] It is obvious that if the brush _5_ is so disposed as to make contact with the disk _3_ only during that portion of the revolution while positive current is being generated, the generator will produce positive pulsations of current, all the negative ones being cut out. If, on the other hand, the spring _5_ may be made to bear on the opposite side of the disk, then it is evident that the positive impulses would all be cut out and the generator would develop only negative impulses. Such a generator is termed a "direct-current" generator or a "pulsating-current" generator. The symbols for magneto or hand generators usually embody a simplified side view, showing the crank and the gears on one side and the shunting or other switching device on the other. Thus in Fig. 78 are shown three such symbols, differing from each other only in the details of the switching device. The one at the left shows the simple shunt, adapted to short-circuit the generator at all times save when it is in operation. The one in the center shows the cut-in, of which another form is described in connection with Fig. 75; while the symbol at the right of Fig. 78 is of the make-and-break device, discussed in connection with Fig. 76. In such diagrammatic representations of generators it is usual to somewhat exaggerate the size of the switching springs, in order to make clear their action in respect to the circuit connections in which the generator is used. Polarized Ringer. The polarized bell or ringer is, as has been stated, the device which is adapted to respond to the currents sent out by the magneto generator. In order that the alternately opposite currents may cause the armature to move alternately in opposite directions, these bells are polarized, _i.e._, given a definite magnetic set, so to speak; so the effect of the currents in the coils is not to create magnetism in normally neutral iron, but rather to alter the magnetism in iron already magnetized. _Western Electric Ringer._ A typical form of polarized bell is shown in Fig. 79, this being the standard bell or ringer of the Western Electric Company. The two electromagnets are mounted side by side, as shown, by attaching their cores to a yoke piece _1_ of soft iron. This yoke piece also carries the standards _2_ upon which the gongs are mounted. The method of mounting is such that the standards may be adjusted slightly so as to bring the gongs closer _to_ or farther _from_, the tapper. The soft iron yoke piece _1_ also carries two brass posts _3_ which, in turn, carry another yoke _4_ of brass. In this yoke _4_ is pivoted, by means of trunnion screws, the armature _5_, this extending on each side of the pivot so that its ends lie opposite the free poles of the electromagnets. From the center of the armature projects the tapper rod carrying the ball or striker which plays between the two gongs. In order that the armature and cores may be normally polarized, a permanent magnet _6_ is secured to the center of the yoke piece _1_. This bends around back of the electromagnets and comes into close proximity to the armature _5_. By this means one end of each of the electromagnet cores is given one polarity--say north--while the armature is given the other polarity--say south. The two coils of the electromagnet are connected together in series in such a way that current in a given direction will act to produce a north pole in one of the free poles and a south pole in the other. If it be assumed that the permanent magnet maintains the armature normally of south polarity and that the current through the coils is of such direction as to make the left-hand core north and the right-hand core south, then it is evident that the left-hand end of the armature will be attracted and the right-hand end repelled. This will throw the tapper rod to the right and sound the right-hand bell. A reversal in current will obviously produce the opposite effect and cause the tapper to strike the left-hand bell. An important feature in polarized bells is the adjustment between the armature and the pole pieces. This is secured in the Western Electric bell by means of the nuts _7_, by which the yoke _4_ is secured to the standards _3_. By moving these nuts up or down on the standards the armature may be brought closer _to_ or farther _from_ the poles, and the device affords ready means for clamping the parts into any position to which they may have been adjusted. [Illustration: Fig. 79. Polarized Bell] _Kellogg Ringer._ Another typical ringer is that of the Kellogg Switchboard and Supply Company, shown in Fig. 80. This differs from that of the Western Electric Company mainly in the details by which the armature adjustment is obtained. The armature supporting yoke _1_ is attached directly to the cores of the magnets, no supporting side rods being employed. Instead of providing means whereby the armature may be adjusted toward or from the poles, the reverse practice is employed, that is, of making the poles themselves extensible. This is done by means of the iron screws _2_ which form extensions of the cores and which may be made to approach or recede from the armature by turning them in such direction as to screw them in or out of the core ends. [Illustration: Fig. 80. Polarized Bell] [Illustration: Fig. 81. Biased Bell] _Biased Bell._ The pulsating-current generator has already been discussed and its principle of operation pointed out in connection with Fig. 77. The companion piece to this generator is the so-called biased ringer. This is really nothing but a common alternating-current polarized ringer with a light spring so arranged as to hold the armature normally in one of its extreme positions so that the tapper will rest against one of the gongs. Such a ringer is shown in Fig. 81 and needs no further explanation. It is obvious that if a current flows in the coils of such a ringer in a direction tending to move the tapper toward the left, then no sound will result because the tapper is already moved as far as it can be in that direction. If, however, currents in the opposite direction are caused to flow through the windings, then the electromagnetic attraction on the armature will overcome the pull of the spring and the tapper will move over and strike the right-hand gong. A cessation of the current will allow the spring to exert itself and throw the tapper back into engagement with the left-hand gong. A series of such pulsations in the proper direction will, therefore, cause the tapper to play between the two gongs and ring the bell as usual. A series of currents in a wrong direction will, however, produce no effect. Conventional Symbols. In Fig. 82 are shown six conventional symbols of polarized bells. The three at the top, consisting merely of two circles representing the magnets in plan view, are perhaps to be preferred as they are well standardized, easy to draw, and rather suggestive. The three at the bottom, showing the ringer as a whole in side elevation, are somewhat more specific, but are objectionable in that they take more space and are not so easily drawn. [Illustration: Fig. 82. Ringer Symbols] Symbols _A_ or _B_ may be used for designating any ordinary polarized ringer. Symbols _C_ and _D_ are interchangeably used to indicate a biased ringer. If the bell is designed to operate only on positive impulses, then the plus sign is placed opposite the symbol, while a minus sign so placed indicates that the bell is to be operated only by negative impulses. Some specific types of ringers are designed to operate only on a given frequency of current. That is, they are so designed as to be responsive to currents having a frequency of sixty cycles per second, for instance, and to be unresponsive to currents of any other frequency. Either symbols _E_ or _F_ may be used to designate such ringers, and if it is desired to indicate the particular frequency of the ringer this is done by adding the proper numeral followed by a short reversed curve sign indicating frequency. Thus 50~ would indicate a frequency of fifty cycles per second. CHAPTER IX THE HOOK SWITCH Purpose. In complete telephone instruments, comprising both talking and signaling apparatus, it is obviously desirable that the two sets of apparatus, for talking and signaling respectively, shall not be connected with the line at the same time. A certain switching device is, therefore, necessary in order that the signaling apparatus alone may be left operatively connected with the line while the instrument is not being used in the transmission of speech, and in order that the signaling apparatus may be cut out when the talking apparatus is brought into play. In instruments employing batteries for the supply of transmitter current, another switching function is the closing of the battery circuit through the transmitter and the induction coil when the instrument is in use for talking, since to leave the battery circuit closed all the time would be an obvious waste of battery energy. In the early forms of telephones these switching operations were performed by a manually operated switch, the position of which the user was obliged to change before and after each use of the telephone. The objection to this was not so much in the manual labor imposed on the user as in the tax on his memory. It was found to be practically a necessity to make this switching function automatic, principally because of the liability of the user to forget to move the switch to the proper position after using the telephone, resulting not only in the rapid waste of the battery elements but also in the inoperative condition of the signal-receiving bell. The solution of this problem, a vexing one at first, was found in the so-called automatic hook switch or switch hook, by which the circuits of the instrument were made automatically to assume their proper conditions by the mere act, on the part of the user, of removing the receiver from, or placing it upon, a conveniently arranged hook or fork projecting from the side of the telephone casing. Automatic Operation. It may be taken as a fundamental principle in the design of any piece of telephone apparatus that is to be generally used by the public, that the necessary acts which a person must perform in order to use the device must, as far as possible, follow as a natural result from some other act which it is perfectly obvious to the user that he must perform. So in the case of the switch hook, the user of a telephone knows that he must take the receiver from its normal support and hold it to his ear; and likewise, when he is through with it, that he must dispose of it by hanging it upon a support obviously provided for that purpose. In its usual form a forked hook is provided for supporting the receiver in a convenient place. This hook is at the free end of a pivoted lever, which is normally pressed upward by a spring when the receiver is not supported on it. When, however, the receiver is supported on it, the lever is depressed by its weight. The motion of the lever is mechanically imparted to the members of the switch proper, the contacts of which are usually enclosed so as to be out of reach of the user. This switch is so arranged that when the hook is depressed the circuits are held in such condition that the talking apparatus will be cut out, the battery circuit opened, and the signaling apparatus connected with the line. On the other hand, when the hook is in its raised position, the signaling apparatus is cut out, the talking apparatus switched into proper working relation with the line, and the battery circuit closed through the transmitter. In the so-called common-battery telephones, where no magneto generator or local battery is included in the equipment at the subscriber's station, the mere raising of the hook serves another important function. It acts, not only to complete the circuit through the substation talking apparatus, but, by virtue of the closure of the line circuit, permits a current to flow over the line from the central-office battery which energizes a signal associated with the line at the central office. This use of the hook switch in the case of the common-battery telephone is a good illustration of the principle just laid down as to making all the functions which the subscriber has to perform depend, as far as possible, on acts which his common sense alone tells him he must do. Thus, in the common-battery telephone the subscriber has only to place the receiver at his ear and ask for what he wants. This operation automatically displays a signal at the central office and he does nothing further until the operator inquires for the number that he wants. He has then nothing to do but wait until the called-for party responds, and after the conversation his own personal convenience demands that he shall dispose of the receiver in some way, so he hangs it up on the most convenient object, the hook switch, and thereby not only places the apparatus at his telephone in proper condition to receive another call, but also conveys to the central office the signal for disconnection. Likewise in the case of telephones operating in connection with automatic exchanges, the hook switch performs a number of functions automatically, of which the subscriber has no conception; and while, in automatic telephones, there are more acts required of the user than in the manual, yet a study of these acts will show that they all follow in a way naturally suggested to the user, so that he need have but the barest fundamental knowledge in order to properly make use of the instrument. In all cases, in properly designed apparatus, the arrangement is such that the failure of the subscriber to do a certain required act will do no damage to the apparatus or to the system, and, therefore, will inconvenience only himself. Design. The hook switch is in reality a two-position switch, and while at present it is a simple affair, yet its development to its high state of perfection has been slow, and its imperfections in the past have been the cause of much annoyance. Several important points must be borne in mind in the design of the hook switch. The spring provided to lift the hook must be sufficiently strong to accomplish this purpose and yet must not be strong enough to prevent the weight of the receiver from moving the switch to its other position. The movement of this spring must be somewhat limited in order that it will not break when used a great many times, and also it must be of such material and shape that it will not lose its elasticity with use. The shape and material of the restoring spring are, of course, determined to a considerable extent by the length of the lever arm which acts on the spring, and on the space which is available for the spring. The various contacts by which the circuit changes are brought about upon the movement of the hook-switch lever usually take the form of springs of German silver or phosphor-bronze, hard rolled so as to have the necessary resiliency, and these are usually tipped with platinum at the points of contact so as to assure the necessary character of surface at the points where the electric circuits are made or broken. A slight sliding movement between each pair of contacts as they are brought together is considered desirable, in that it tends to rub off any dirt that may have accumulated, yet this sliding movement should not be great, as the surfaces will then cut each other and, therefore, reduce the life of the switch. Contact Material. On account of the high cost of platinum, much experimental work has been done to find a substitute metal suitable for the contact points in hook switches and similar uses in the manufacture of telephone apparatus. Platinum is unquestionably the best known material, on account of its non-corrosive and heat-resisting qualities. Hard silver is the next best and is found in some first-class apparatus. The various cheap alloys intended as substitutes for platinum or silver in contact points may be dismissed as worthless, so far as the writers' somewhat extensive investigations have shown. In the more recent forms of hook switches, the switch lever itself does not form a part of the electrical circuit, but serves merely as the means by which the springs that are concerned in the switching functions are moved into their alternate cooperative relations. One advantage in thus insulating the switch lever from the current-carrying portions of the apparatus and circuits is that, since it necessarily projects from the box or cabinet, it is thus liable to come in contact with the person of the user. By insulating it, all liability of the user receiving shocks by contact with it is eliminated. Wall Telephone Hooks. _Kellogg._ A typical form of hook switch, as employed in the ordinary wall telephone sets, is shown in Fig. 83, this being the standard hook of the Kellogg Switchboard and Supply Company. In this the lever _1_ is pivoted at the point _3_ in a bracket _5_ that forms the base of all the working parts and the means of securing the entire hook switch to the box or framework of the telephone. This switch lever is normally pressed upward by a spring _2_, mounted on the bracket _5_, and engaging the under side of the hook lever at the point _4_. Attached to the lever arm _1_ is an insulated pin _6_. The contact springs by which the various electrical circuits are made and broken are shown at _7_, _8_, _9_, _10_, and _11_, these being mounted in one group with insulated bushings between them; the entire group is secured by machine screws to a lug projecting horizontally from the bracket _5_. The center spring _9_ is provided with a forked extension which embraces the pin _6_ on the hook lever. It is obvious that an up-and-down motion of the hook lever will move the long spring _9_ in such manner as to cause electrical contact either between it and the two upper springs _7_ and _8_, or between it and the two lower springs _10_ and _11_. The hook is shown in its raised position, which is the position required for talking. When lowered the two springs _7_ and _8_ are disengaged from the long spring _9_ and from each other, and the three springs _9_, _10_, and _11_ are brought into electrical engagement, thus establishing the necessary signaling conditions. [Illustration: Fig. 83. Long Lever Hook Switch] The right-hand ends of the contact springs are shown projecting beyond the insulating supports. This is for the purpose of facilitating making electrical joints between these springs and the various wires which lead from them. These projecting ends are commonly referred to as ears, and are usually provided with holes or notches into which the connecting wire is fastened by soldering. _Western Electric._ Fig. 84 shows the type of hook switch quite extensively employed by the Western Electric Company in wall telephone sets where the space is somewhat limited and a compact arrangement is desired. It will readily be seen that the principle on which this hook switch operates is similar to that employed in Fig. 83, although the mechanical arrangement of the parts differs radically. The hook lever _1_ is pivoted at _3_ on a bracket _2_, which serves to support all the other parts of the switch. The contact springs are shown at _4_, _5_, and _6_, and this latter spring _6_ is so designed as to make it serve as an actuating spring for the hook. This is accomplished by having the curved end of this spring press against the lug _7_ of the hook and thus tend to raise the hook when it is relieved of the weight of the receiver. The two shorter springs _8_ and _9_ have no electrical function but merely serve as supports against which the springs _4_ and _5_ may rest, when the receiver is on the hook, these springs _4_ and _5_ being given a light normal tension toward the stop springs _8_ and _9_. It is obvious that in the particular arrangement of the springs in this switch no contacts are closed when the receiver is on the hook. [Illustration: Fig. 84. Short Lever Hook Switch] Concerning this latter feature, it will be noted that the particular form of Kellogg hook switch, shown in Fig. 83, makes two contacts and breaks two when it is raised. Similarly the Western Electric Company's makes two contacts but does not break any when raised. From such considerations it is customary to speak of a hook such as that shown in Fig. 83 as having two make and two break contacts, and such a hook as that shown in Fig. 84 as having two make contacts. It will be seen from either of these switches that the modification of the spring arrangement, so as to make them include a varying number of make-and-break contacts, is a simple matter, and switches of almost any type are readily modified in this respect. [Illustration: Fig. 85. Removable Lever Hook Switch] _Dean_. In Fig. 85 is shown a decidedly unique hook switch for wall telephone sets which forms the standard equipment of the Dean Electric Company. The hook lever _1_ is pivoted at _2_, an auxiliary lever _3_ also being pivoted at the same point. The auxiliary lever _3_ carries at its rear end a slotted lug _4_, which engages the long contact spring _5_, and serves to move it up and down so as to engage and disengage the spring _6_, these two springs being mounted on a base lug extending from the base plate _7_, upon which the entire hook-switch mechanism is mounted. The curved spring _8_, also mounted on this same base, engages the auxiliary lever _3_ at the point _9_ and normally serves to press this up so as to maintain the contact springs _5_ in engagement with contact spring _6_. The switch springs are moved entirely by the auxiliary lever _3_, but in order that this lever _3_ may be moved as required by the hook lever _1_, this lever is provided with a notched lug _10_ on its lower side, which notch is engaged by a forwardly projecting lug _11_ that is integral with the auxiliary lever _3_. The switch lever may be bodily removed from the remaining parts of the hook switch by depressing the lug _11_ with the finger, so that it disengages the notch in lug _10_, and then drawing the hook lever out of engagement with the pivot stud _2_, as shown in the lower portion of the figure. It will be noted that the pivotal end of the hook lever is made with a slot instead of a hole as is the customary practice. The advantage of being able to remove the hook switch bodily from the other portions arises mainly in connection with the shipment or transportation of instruments. The projecting hooks cause the instruments to take up more room and thus make larger packing boxes necessary than would otherwise be used. Moreover, in handling the telephones in store houses or transporting them to the places where they are to be used, the projecting hook switch is particularly liable to become damaged. It is for convenience under such conditions that the Dean hook switch is made so that the switch lever may be removed bodily and placed, for instance, inside the telephone box for transportation. Desk-Stand Hooks. The problem of hook-switch design for portable desk telephones, while presenting the same general characteristics, differs in the details of construction on account of the necessarily restricted space available for the switch contacts in the desk telephone. [Illustration: WEST OFFICE OF HOME TELEPHONE COMPANY, SAN FRANCISCO Serving the General Western Business and Residence Districts.] _Western Electric._ In Fig. 86 is shown an excellent example of hook-switch design as applied to the requirements of the ordinary portable desk set. This figure is a cross-sectional view of the base and standard of a familiar type of desk telephone. The base itself is of stamped metal construction, as indicated, and the standard which supports the transmitter and the switch hook for the receiver is composed of a black enameled or nickel-plated brass tube _1_, attached to the base by a screw-threaded joint, as shown. The switch lever _2_ is pivoted at _3_ in a brass plug _4_, closing the upper end of the tube forming the standard. This brass plug supports also the transmitter, which is not shown in this figure. Attached to the plug _4_ by the screw _5_ is a heavy strip _6_, which reaches down through the tube to the base plate of the standard and is held therein by a screw _7_. The plug _4_, carrying with it the switch-hook lever _2_ and the brass strip _6_, may be lifted bodily out of the standard _1_ by taking out the screw _7_ which holds the strip _6_ in place, as is clearly indicated. On the strip _6_ there is mounted the group of switch springs by which the circuit changes of the instrument are brought about when the hook is raised or lowered. The spring _8_ is longer than the others, and projects upwardly far enough to engage the lug on the switch-hook lever _2_. This spring, which is so bent as to close the contacts at the right when not prevented by the switch lever, also serves as an actuating spring to raise the lever _2_ when the receiver is removed from it. This spring, when the receiver is removed from the hook, engages the two springs at the right, as shown, or when the receiver is placed on the hook, breaks contact with the two right-hand springs and makes contact respectively with the left-hand spring and also with the contact _9_ which forms the transmitter terminal. [Illustration: Fig. 86. Desk-Stand Hook Switch] It is seen from an inspection of this switch hook that it has two make and two break contacts. The various contact springs are connected with the several binding posts shown, these forming the connectors for the flexible cord conductors leading into the base and up through the standard of the desk stand. By means of the conductors in this cord the circuits are led to the other parts of the instrument, such as the induction coil, call bell, and generator, if there is one, which, in the case of the Western Electric Company's desk set, are all mounted separately from the portable desk stand proper. This hook switch is accessible in an easy manner and yet not subject to the tampering of idle or mischievous persons. By taking out the screw _7_ the entire hook switch may be lifted out of the tube forming the standard, the cords leading to the various binding posts being slid along through the tube. By this means the connections to the hook switch, as well as the contact of the switch itself, are readily inspected or repaired by those whose duty it is to perform such operations. _Kellogg._ In Fig. 87 is shown a sectional view of the desk-stand hook switch of the Kellogg Switchboard and Supply Company. In this it will be seen that instead of placing the switch-hook springs within the standard or tube, as in the case of the Western Electric Company, they are mounted in the base where they are readily accessible by merely taking off the base plate from the bottom of the stand. The hook lever operates on the long spring of the group of switch springs by means of a toggle joint in an obvious manner. This switch spring itself serves by its own strength to raise the hook lever when released from the weight of the receiver. [Illustration: Fig. 87. Desk-Stand Hook Switch] In this switch, the hook lever, and in fact the entire exposed metal portions of the instrument, are insulated from all of the contact springs and, therefore, there is little liability of shocks on the part of the person using the instrument. Conventional Symbols. The hook switch plays a very important part in the operation of telephone circuits; for this reason readily understood conventional symbols, by which they may be conveniently represented in drawings of circuits, are desirable. In Fig. 88 are shown several symbols such as would apply to almost any circuit, regardless of the actual mechanical details of the particular hook switch which happened to be employed. Thus diagram _A_ in Fig. 88 shows a hook switch having a single make contact and this diagram might be used to refer to the hook switch of the Dean Electric Company shown in Fig. 85, in which only a single contact is made when the receiver is removed, and none is made when it is on the hook. Similarly, diagram _B_ might be used to represent the hook switch of the Kellogg Company, shown in Fig. 83, the arrangement being for two make and two break contacts. Likewise diagram _C_ might be used to represent the hook switch of the Western Electric Company, shown in Fig. 84, which, as before stated, has two make contacts only. Diagram _D_ shows another modification in which contacts made by the hook switch, when the receiver is removed, control two separate circuits. Assuming that the solid black portion represents insulation, it is obvious that the contacts are divided into two groups, one insulated from the other. [Illustration: Fig. 88. Hook Switch Symbols] [Illustration: COMPRESSED AIR WAGON FOR PNEUMATIC DRILLING AND CHIPPING IN MANHOLES] CHAPTER X ELECTROMAGNETS AND INDUCTIVE COILS Electromagnet. The physical thing which we call an electromagnet, consisting of a coil or helix of wire, the turns of which are insulated from each other, and within which is usually included an iron core, is by far the most useful of all the so-called translating devices employed in telephony. In performing the ordinary functions of an electromagnet it translates the energy of an electrical current into the energy of mechanical motion. An almost equally important function is the converse of this, that is, the translation of the energy of mechanical motion into that of an electrical current. In addition to these primary functions which underlie the art of telephony, the electromagnetic coil or helix serves a wide field of usefulness in cases where no mechanical motion is involved. As impedance coils, they serve to exert important influences on the flow of currents in circuits, and as induction coils, they serve to translate the energy of a current flowing in one circuit into the energy of a current flowing in another circuit, the translation usually, but not always, being accompanied by a change in voltage. When a current flows through the convolutions of an ordinary helix, the helix will exhibit the properties of a magnet even though the substance forming the core of the helix is of non-magnetic material, such as air, or wood, or brass. If, however, a mass of iron, such as a rod or a bundle of soft iron wires, for instance, is substituted as a core, the magnetic properties will be enormously increased. The reason for this is, that a given magnetizing force will set up in iron a vastly greater number of lines of magnetic force than in air or in any other non-magnetic material. Magnetizing Force. The magnetizing force of a given helix is that force which tends to drive magnetic lines of force through the magnetic circuit interlinked with the helix. It is called _magnetomotive force_ and is analogous to electromotive force, that is, the force which tends to drive an electric current through a circuit. The magnetizing force of a given helix depends on the product of the current strength and the number of turns of wire in the helix. Thus, when the current strength is measured in amperes, this magnetizing force is expressed as ampere-turns, being the product of the number of amperes flowing by the number of turns. The magnetizing force exerted by a given current, therefore, is independent of anything except the number of turns, and the material within the core or the shape of the core has no effect upon it. Magnetic Flux. The total magnetization resulting from a magnetizing force is called the magnetic flux, and is analogous to current. The intensity of a magnetic flux is expressed by the number of magnetic lines of force in a square centimeter or square inch. While the magnetomotive force or magnetizing force of a given helix is independent of the material of the core, the flux which it sets up is largely dependent on the material and shape of the core--not only upon this but on the material that lies in the return path for the flux outside of the core. We may say, therefore, that the amount of flux set up by a given current in a given coil or helix is dependent on the material in the magnetic path or magnetic circuit, and on the shape and length of that circuit. If the magnetic circuit be of air or brass or wood or any other non-magnetic material, the amount of flux set up by a given magnetizing force will be relatively small, while it will be very much greater if the magnetic circuit be composed in part or wholly of iron or steel, which are highly magnetic substances. Permeability. The quality of material, which permits of a given magnetizing force setting up a greater or less number of lines of force within it, is called its permeability. More accurately, the permeability is the ratio existing between the amount of magnetization and the magnetizing force which produces such magnetization. The permeability of a substance is usually represented by the Greek letter µ (pronounced _mu_). The intensity of the magnetizing force is commonly symbolized by H, and since the permeability of air is always taken as unity, we may express the intensity of magnetizing force by the number of lines of force per square centimeter which it sets up in air. Now, if the space on which the given magnetizing force H were acting were filled with iron instead of air, then, owing to the greater permeability of iron, there would be set up a very much greater number of lines of force per square centimeter, and this number of lines of force per square centimeter in the iron is the measure of the magnetization produced and is commonly expressed by the letter =B=. From this we have µ = B/H Thus, when we say that the permeability of a given specimen of wrought iron under given conditions is 2,000, we mean that 2,000 times as many lines of force would be induced in a unit cross-section of this sample as would be induced by the same magnetizing force in a corresponding unit cross-section of air. Evidently for air B = H, hence µ becomes unity. The permeability of air is always a constant. This means that whether the magnetic density of the lines of force through the air be great or small the number of lines will always be proportional to the magnetizing force. Unfortunately for easy calculations in electromagnetic work, however, this is not true of the permeability of iron. For small magnetic densities the permeability is very great, but for large densities, that is, under conditions where the number of lines of force existing in the iron is great, the permeability becomes smaller, and an increase in the magnetizing force does not produce a corresponding increase in the total flux through the iron. Magnetization Curves. This quality of iron is best shown by the curves of Fig. 89, which illustrate the degree of magnetization set up in various kinds of iron by different magnetizing forces. In these curves the ordinates represent the total magnetization =B=, while the abscissas represent the magnetizing force =H=. It is seen from an inspection of these curves that as the magnetizing force =H= increases, the intensity of flux also increases, but at a gradually lessening rate, indicating a reduction in permeability at the higher densities. These curves are also instructive as showing the great differences that exist between the permeability of the different kinds of iron; and also as showing how, when the magnetizing force becomes very great, the iron approaches what is called _saturation_, that is, a point at which the further increase in magnetizing force will result in no further magnetization of the core. From the data of the curves of Fig. 89, which are commonly called _magnetization curves_, it is easy to determine other data from which so-called permeability curves may be plotted. In permeability curves the total magnetization of the given pieces of iron are plotted as abscissas, while the corresponding permeabilities are plotted as ordinates. [Illustration: Fig. 89. Magnetization Curve] Direction of Lines of Force. The lines of force set up within the core of a helix always have a certain direction. This direction always depends upon the direction of the flow of current around the core. An easy way to remember the direction is to consider the helix as grasped in the right hand with the fingers partially encircling it and the thumb pointing along its axis. Then, if the current through the convolutions of the helix be in the direction in which the fingers of the hand are pointed around the helix, the magnetic lines of force will proceed through the core of the helix along the direction in which the thumb is pointed. In the case of a simple bar electromagnet, such as is shown in Fig. 90, the lines of force emerging from one end of the bar must pass back through the air to the other end of the bar, as indicated by dotted lines and arrows. The path followed by the magnetic lines of force is called the _magnetic circuit_, and, therefore, the magnetic circuit of the magnet shown in Fig. 90 is composed partly of iron and partly of air. From what has been said concerning the relative permeability of air and of iron, it will be obvious that the presence of such a long air path in the magnetic circuit will greatly reduce the number of lines of force that a given magnetizing force can set up. The presence of an air gap in a magnetic circuit has much the same effect on the total flow of lines of force as the presence of a piece of bad conductor in a circuit composed otherwise of good conductor, in the case of the flow of electric current. Reluctance. As the property which opposes the flow of electric current in an electrical circuit is called _resistance_, so the property which opposes the flow of magnetic lines of force in a magnetic circuit is called _reluctance_. In the case of the electric circuit, the resistance is the reciprocal of the conductivity; in the case of the magnetic circuit, the reluctance is the reciprocal of the permeability. As in the case of an electrical circuit, the amount of flow of current is equal to the electromotive force divided by the resistance; so in a magnetic circuit, the magnetic flux is equal to the magnetizing force or magnetomotive force divided by the reluctance. [Illustration: Fig. 90. Bar Electromagnet] Types of Low-Reluctance Circuits. As the pull of an electromagnet upon its armature depends on the total number of lines of force passing from the core to the armature--that is, on the total flux--and as the total flux depends for a given magnetizing force on the reluctance of the magnetic circuit, it is obvious that the design of the electromagnetic circuit is of great importance in influencing the action of the magnet. Obviously, anything that will reduce the amount of air or other non-magnetic material that is in the magnetic circuit will tend to reduce the reluctance, and, therefore, to increase the total magnetization resulting from a given magnetizing force. _Horseshoe Form._ One of the easiest and most common ways of reducing reluctance in a circuit is to bend the ordinary bar electromagnet into horseshoe form. In order to make clear the direction of current flow, attention is called to Fig. 91. This is intended to represent a simple bar of iron with a winding of one direction throughout its length. The gap in the middle of the bar, which divides the winding into two parts, is intended merely to mark the fact that the winding need not cover the whole length of the bar and still will be able to magnetize the bar when the current passes through it. In Fig. 92 a similar bar is shown with similar winding upon it, but bent into =U=-form, exactly as if it had been grasped in the hand and bent without further change. The magnetic polarity of the two ends of the bar remain the same as before for the same direction of current, and it is obvious that the portion of the magnetic circuit which extends through air has been very greatly shortened by the bending. As a result, the magnetic reluctance of the circuit has been greatly decreased and the strength of the magnet correspondingly increased. [Illustration: Fig. 91. Bar Electromagnet] [Illustration: Fig. 92. Horseshoe Electromagnet] [Illustration: Fig. 93. Horseshoe Electromagnet] If the armature of the electromagnet shown in Fig. 92 is long enough to extend entirely across the air gap from the south to the north pole, then the air gap in the magnetic circuit is still further shortened, and is now represented only by the small gap between the ends of the armature and the ends of the core. Such a magnet, with an armature closely approaching the poles, is called a _closed-circuit magnet_, since the only gap in the iron of the magnetic circuit is that across which the magnet pulls in attracting its armature. In Fig. 93 is shown the electrical and magnetic counterpart of Fig. 92. The fact that the magnetic circuit is not a single iron bar but is made up of two cores and one backpiece rigidly secured together, has no bearing upon the principle, but only shows that a modification of construction is possible. In the construction of Fig. 93 the armature _1_ is shown as being pulled directly against the two cores _2_ and _3_, these two cores being joined by a yoke _4_, which, like the armature and the core, is of magnetic material. The path of the lines of force is indicated by dotted lines. This is a very important form of electromagnet and is largely used in telephony. _Iron-Clad Form_. Another way of forming a closed-circuit magnet that is widely used in telephony is to enclose the helix or winding in a shell of magnetic material which joins the core at one end. This construction results in what is known as the _tubular_ or _iron-clad_ electromagnet, which is shown in section and in end view in Fig. 94. In this the core _1_ is a straight bar of iron and it lies centrally within a cylindrical shell _2_, also of iron. The bar is usually held in place within the shell by a screw, as shown. The lines of force set up in the core by the current flowing through the coil, pass to the center of the bottom of the iron shell and thence return through the metal of the shell, through the air gap between the edges of the shell and the armature, and then concentrate at the center of the armature and pass back to the end of the core. This is a highly efficient form of closed-circuit magnet, since the magnetic circuit is of low reluctance. [Illustration: Fig. 94. Iron-Clad Electromagnet] Such forms of magnets are frequently used where it is necessary to mount a large number of them closely together and where it is desired that the current flowing in one magnet shall produce no inductive effect in the coils of the adjacent magnets. The reason why mutual induction between adjacent magnets is obviated in the case of the iron-clad or tubular magnet is that practically all stray field is eliminated, since the return path for the magnetic lines is so completely provided for by the presence of the iron shell. _Special Horseshoe Form._ In Fig. 95 is shown a type of relay commonly employed in telephone circuits. The purpose of illustrating it in this chapter is not to discuss relays, but rather to show an adaptation of an electromagnet wherein low reluctance of the magnetic circuit is secured by providing a return leg for the magnetic lines developed in the core, thus forming in effect a horseshoe magnet with a winding on one of its limbs only. To the end of the core _1_ there is secured an =L=-shaped piece of soft iron _2_. This extends upwardly and then forwardly throughout the entire length of the magnet core. An =L=-shaped armature _3_ rests on the front edge of the piece _2_ so that a slight rocking motion will be permitted on the "knife-edge" bearing thus afforded. It is seen from the dotted lines that the magnetic circuit is almost a closed one. The only gap is that between the lower end of the armature _3_ and the front end of the core. When the coil is energized, this gap is closed by the attraction of the armature. As a result, the rearwardly projecting end of the armature _3_ is raised and this raises the spring _4_ and causes it to break the normally existing contact with the spring _5_ and to establish another contact with the spring _6_. Thus the energy developed within the coil of the magnet is made to move certain parts which in turn operate the switching devices to produce changes in electrical circuits. These relays and other adaptations of the electromagnet will be discussed more fully later on. [Illustration: Fig. 95. Electromagnet of Relay] There are almost numberless forms of electromagnets, but we have illustrated here examples of the principal types employed in telephony, and the modifications of these types will be readily understood in view of the general principles laid down. Direction of Armature Motion. It may be said in general that the armature of an electromagnet always moves or tends to move, when the coil is energized, in such a way as to reduce the reluctance of the magnetic circuit through the coil. Thus, in all of the forms of electromagnets discussed, the armature, when attracted, moves in such a direction as to shorten the air gap and to introduce the iron of the armature as much as possible into the path of the magnetic lines, thus reducing the reluctance. In the case of a solenoid type of electromagnet, or the coil and plunger type, which is a better name than solenoid, the coil, when energized, acts in effect to suck the iron core or plunger within itself so as to include more and more of the iron within the most densely occupied portion of the magnetic circuit. [Illustration: Fig. 96. Parallel Differential Electromagnet] Differential Electromagnet. Frequently in telephony, the electromagnets are provided with more than one winding. One purpose of the double-wound electromagnet is to produce the so-called differential action between the two windings, _i.e._, making one of the windings develop magnetization in the opposite direction from that of the other, so that the two will neutralize each other, or at least exert different and opposite influences. The principle of the differential electromagnet may be illustrated in connection with Fig. 96. Here two wires _1_ and _2_ are shown wrapped in the same direction about an iron core, the ends of the wire being joined together at _3_. Obviously, if one of these windings only is employed and a current sent through it, as by connecting the terminals of a battery with the points _4_ and _3_, for instance, the core will be magnetized as in an ordinary magnet. Likewise, the core will be energized if a current be sent from _5_ to _3_. Assuming that the two windings are of equal resistance and number of turns, the effects so produced, when either the coil _1_ or the coil _2_ is energized, will be equal. If the battery be connected between the terminals _4_ and _5_ with the positive pole, say, at _5_, then the current will proceed through the winding _2_ and tend to generate magnetism in the core in the direction of the arrow. After traversing the winding _2_, however, it will then begin to traverse the other winding _1_ and will pass around the core in the opposite direction throughout the length of that winding. This will tend to set up magnetism in the core in the opposite direction to that indicated by the arrow. Since the two currents are equal and also the number of turns in each winding, it is obvious that the two magnetizing influences will be exactly equal and opposite and no magnetic effect will be produced. Such a winding, as is shown in Fig. 96, where the two wires are laid on side by side, is called a _parallel differential winding_. Another way of winding magnets differentially is to put one winding on one end of the core and the other winding on the other end of the core and connect these so as to cause the currents through them to flow around the core in opposite directions. Such a construction is shown in Fig. 97 and is called a _tandem differential winding_. The tandem arrangement, while often good enough for practical purposes, cannot result in the complete neutralization of magnetic effect. This is true because of the leakage of some of the lines of force from intermediate points in the length of the core through the air, resulting in some of the lines passing through more of the turns of one coil than of the other. Complete neutralization can only be attained by first twisting the two wires together with a uniform lay and then winding them simultaneously on the core. [Illustration: Fig. 97. Tandem Differential Electromagnet] Mechanical Details. We will now consider the actual mechanical construction of the electromagnet. This is a very important feature of telephone work, because, not only must the proper electrical and magnetic effects be produced, but also the whole structure of the magnet must be such that it will not easily get out of order and not be affected by moisture, heat, careless handling, or other adverse conditions. The most usual form of magnet construction employed in telephony is shown in Fig. 98. On the core, which is of soft Norway iron, usually cylindrical in form, are forced two washers of either fiber or hard rubber. Fiber is ordinarily to be preferred because it is tougher and less liable to breakage. Around the core, between the two heads, are then wrapped several layers of paper or specially prepared cloth in order that the wire forming the winding may be thoroughly insulated from the core. One end of the wire is then passed through a hole in one of the spool heads or washers, near the core, and the wire is then wound on in layers. Sometimes a thickness of paper is placed around each layer of wire in order to further guard against the breaking down of the insulation between layers. When the last layer is wound on, the end of the wire is passed out through a hole in the head, thus leaving both ends projecting. [Illustration: Fig. 98 Construction of Electromagnet] Magnet Wire. The wire used in winding magnets is, of course, an important part of the electromagnet. It is always necessary that the adjacent turns of the wire be insulated from each other so that the current shall be forced to pass around the core through all the length of wire in each turn rather than allowing it to take the shorter and easier path from one turn to the next, as would be the case if the turns were not insulated. For this purpose the wire is usually covered with a coating of some insulating material. There are, however, methods of winding magnet coils with bare wire and taking care of the insulation between the turns in another way, as will be pointed out. Insulated wire for the purpose of winding magnet coils is termed _magnet wire_. Copper is the material almost universally employed for the conductor. Its high conductivity, great ductility, and low cost are the factors which make it superior to all other metals. However, in special cases, where exceedingly high conductivity is required with a limited winding space, silver wire is sometimes employed, and on the other hand, where very high resistance is desired within a limited winding space, either iron or German silver or some other high-resistance alloy is used. _Wire Gauges_. Wire for electrical purposes is drawn to a number of different standard gauges. Each of the so-called wire gauges consists of a series of graded sizes of wire, ranging from approximately one-half an inch in diameter down to about the fineness of a lady's hair. In certain branches of telephone work, such as line construction, the existence of the several wire gauges or standards is very likely to lead to confusion. Fortunately, however, so far as magnet wire is concerned, the so-called Brown and Sharpe, or American, wire gauge is almost universally employed in this country. The abbreviations for this gauge are B.&S. or A.W.G. TABLE III Copper Wire Table Giving weights, lengths, and resistances of wire @ 68° F., of Matthiessen's Standard Conductivity. +-------+----------+----------+-----------------------+--------------------+-----------------------+ | | | | RESISTANCE | LENGTH | WEIGHT | | A.W.G.| DIAMETER | AREA +-----------------------+--------------------+-----------------------+ | B.&S. | MILS | CIRCULAR | OHMS PER | OHMS PER | FEET PER | FEET PER| POUNDS PER |POUNDS PER| | | | MILS | POUND | FOOT | POUND | OHM | FOOT | OHM | +-------+----------+----------+-----------+-----------+----------+---------+------------+----------+ | 0000 | 460. | 211,600. |0.00007639 | 0.0000489 | 1.561 | 20,440. | 0.6405 | 13,090. | | 000 | 409.6 | 167,800. |0.0001215 | 0.0000617 | 1.969 | 16,210. | 0.5080 | 8,232. | | 00 | 364.8 | 133,100. |0.0001931 | 0.0000778 | 2.482 | 12,850. | 0.4028 | 5,177. | | 0 | 324.9 | 105,500. |0.0003071 | 0.0000981 | 3.130 | 10,190. | 0.3195 | 3,256. | +-------+----------+----------+-----------+-----------+----------+---------+------------+----------+ | 1 | 289.3 | 83,690. | 0.0004883 | 0.0001237 | 3.947 | 8,083. | 0.2533 | 2,048. | | 2 | 257.6 | 66,370. | 0.0007765 | 0.0001560 | 4.977 | 6,410. | 0.2009 | 1,288. | | 3 | 229.4 | 52,630. | 0.001235 | 0.0001967 | 6.276 | 5,084. | 0.1593 | 810.0 | | 4 | 204.3 | 41,740. | 0.001963 | 0.0002480 | 7.914 | 4,031. | 0.1264 | 509.4 | | 5 | 181.9 | 33,100. | 0.003122 | 0.0003128 | 9.980 | 3,197. | 0.1002 | 320.4 | | 6 | 162.0 | 26,250. | 0.004963 | 0.0003944 | 12.58 | 2,535. | 0.07946 | 201.5 | | 7 | 144.3 | 20,820. | 0.007892 | 0.0004973 | 15.87 | 2,011. | 0.06302 | 126.7 | | 8 | 128.5 | 16,510. | 0.01255 | 0.0006271 | 20.01 | 1,595. | 0.04998 | 79.69 | | 9 | 114.4 | 13,090. | 0.01995 | 0.0007908 | 25.23 | 1,265. | 0.03963 | 50.12 | | 10 | 101.9 | 10,380. | 0.03173 | 0.0009273 | 31.82 | 1,003. | 0.03143 | 31.52 | +-------+----------+----------+-----------+-----------+----------+---------+------------+----------+ | 11 | 90.74 | 8,234. | 0.05045 | 0.001257 | 40.12 | 795.3 | 0.02493 | 19.82 | | 12 | 80.81 | 6,530. | 0.08022 | 0.001586 | 50.59 | 630.7 | 0.01977 | 12.47 | | 13 | 71.96 | 5,178. | 0.1276 | 0.001999 | 63.79 | 500.1 | 0.01568 | 7.840 | | 14 | 64.08 | 4,107. | 0.2028 | 0.002521 | 80.44 | 396.6 | 0.01243 | 4.931 | | 15 | 57.07 | 3,257. | 0.3225 | 0.003179 | 101.4 | 314.5 | 0.009858 | 3.101 | | 16 | 50.82 | 2,583. | 0.5128 | 0.004009 | 127.9 | 249.4 | 0.007818 | 1.950 | | 17 | 45.26 | 2,048. | 0.8153 | 0.005055 | 161.3 | 197.8 | 0.006200 | 1.226 | | 18 | 40.30 | 1,624. | 1.296 | 0.006374 | 203.4 | 156.9 | 0.004917 | 0.7713 | | 19 | 35.89 | 1,288. | 2.061 | 0.008038 | 256.5 | 124.4 | 0.003899 | 0.4851 | | 20 | 31.96 | 1,022. | 3.278 | 0.01014 | 323.4 | 98.66 | 0.003092 | 0.3051 | +-------+----------+----------+-----------+-----------+----------+---------+------------+----------+ | 21 | 28.46 | 810.1 | 5.212 | 0.01278 | 407.8 | 78.24 | 0.002452 | 0.1919 | | 22 | 25.35 | 642.4 | 8.287 | 0.01612 | 514.2 | 62.05 | 0.001945 | 0.1207 | | 23 | 22.57 | 509.5 | 13.18 | 0.02032 | 648.4 | 49.21 | 0.001542 | 0.07589 | | 24 | 20.10 | 404.0 | 20.95 | 0.02563 | 817.6 | 39.02 | 0.001223 | 0.04773 | | 25 | 17.90 | 320.4 | 33.32 | 0.03231 | 1,031. | 30.95 | 0.0009699 | 0.03002 | | 26 | 15.94 | 254.1 | 52.97 | 0.04075 | 1,300. | 24.54 | 0.0007692 | 0.1187 | | 27 | 14.2 | 201.5 | 84.23 | 0.05138 | 1,639. | 19.46 | 0.0006100 | 0.01888 | | 28 | 12.64 | 159.8 | 133.9 | 0.06479 | 2,067. | 15.43 | 0.0004837 | 0.007466 | | 29 | 11.26 | 126.7 | 213.0 | 0.08170 | 2,607. | 12.24 | 0.0003836 | 0.004696 | | 30 | 10.03 | 100.5 | 338.6 | 0.1030 | 3,287. | 9.707 | 0.0003042 | 0.002953 | +-------+----------+----------+-----------+-----------+----------+---------+------------+----------+ | 31 | 8.928 | 79.70 | 538.4 | 0.1299 | 4,145. | 7.698 | 0.0002413 |0.001857 | | 32 | 7.950 | 63.21 | 856.2 | 0.1638 | 5,227. | 6.105 | 0.0001913 |0.001168 | | 33 | 7.080 | 50.13 | 1,361. | 0.2066 | 6,591. | 4.841 | 0.0001517 |0.0007346 | | 34 | 6.305 | 39.75 | 2,165. | 0.2605 | 8,311. | 3.839 | 0.0001203 |0.0004620 | | 35 | 5.615 | 31.52 | 3,441. | 0.3284 | 10,480. | 3.045 | 0.00009543 |0.0002905 | | 36 | 5.0 | 25.0 | 5,473. | 0.4142 | 13,210. | 2.414 | 0.00007568 |0.0001827 | | 37 | 4.453 | 19.83 | 8,702. | 0.5222 | 16,660. | 1.915 | 0.00006001 |0.0001149 | | 38 | 3.965 | 15.72 | 13,870. | 0.6585 | 21,010. | 1.519 | 0.00004759 |0.00007210| | 39 | 3.531 | 12.47 | 22,000. | 0.8304 | 26,500. | 1.204 | 0.00003774 |0.00004545| | 40 | 3.145 | 9.888 | 34,980. | 1.047 | 33,410. | 0.9550 | 0.00002993 |0.00002858| +-------+----------+----------+-----------+-----------+----------+---------+------------+----------+ [Illustration: SOUTH OFFICE OF HOME TELEPHONE COMPANY, SAN FRANCISCO] In the Brown and Sharpe gauge the sizes, beginning with the largest, are numbered 0000, 000, 00, 0, 1, 2, and so on up to 40. Sizes larger than about No. 16 B.&S. gauge are seldom used as magnet wire in telephony, but for the purpose of making the list complete, Table III is given, including all of the sizes of the B.&S. gauge. In Table III there is given for each gauge number the diameter of the wire in mils (thousandths of an inch); the cross-sectional area in circular mils (a unit area equal to that of a circle having a diameter of one one-thousandth of an inch); the resistance of the wire in various units of length and weight; the length of the wire in terms of resistance and of weight; and the weight of the wire in terms of its length and resistance. It is to be understood that in Table III the wire referred to is bare wire and is of pure copper. It is not commercially practicable to use absolutely pure copper, and the ordinary magnet wire has a conductivity equal to about 98 per cent of that of pure copper. The figures given in this table are sufficiently accurate for all ordinary practical purposes. _Silk and Cotton Insulation_. The insulating material usually employed for covering magnet wire is of silk or cotton. Of these, silk is by far the better material for all ordinary purposes, since it has a much higher insulating property than cotton, and is very much thinner. Cotton, however, is largely employed, particularly in the larger sizes of magnet wire. Both of these materials possess the disadvantage of being hygroscopic, that is, of readily absorbing moisture. This disadvantage is overcome in many cases by saturating the coil after it is wound in some melted insulating compound, such as wax or varnish or asphaltum, which will solidify on cooling. Where the coils are to be so saturated the best practice is to place them in a vacuum chamber and exhaust the air, after which the hot insulating compound is admitted and is thus drawn into the innermost recesses of the winding space. Silk-insulated wire, as regularly produced, has either one or two layers of silk. This is referred to commercially as single silk wire or as double silk wire. The single silk has a single layer of silk fibers wrapped about it, while the double silk has a double layer, the two layers being put on in reverse direction. The same holds true of cotton insulated wire. Frequently, also, there is a combination of the two, consisting of a single or a double wrapping of silk next to the wire with an outer wrapping of cotton. Where this is done the cotton serves principally as a mechanical protection for the silk, the principal insulating properties residing in the silk. _Enamel_. A later development in the insulation of magnet wire has resulted in the so-called enamel wire. In this, instead of coating the wire with some fibrous material such as silk or cotton, the wire is heated and run through a bath of fluid insulating material or liquid enamel, which adheres to the wire in a very thin coating. The wire is then run through baking ovens, so that the enamel is baked on. This process is repeated several times so that a number of these thin layers of the enamel are laid on and baked in succession. The characteristics sought in good enamel insulation for magnet wire may be thus briefly set forth: It is desirable for the insulation to possess the highest insulating qualities; to have a glossy, flawless surface; to be hard without being brittle; to adhere tenaciously and stand all reasonable handling without cracking or flaking; to have a coefficient of elasticity greater than the wire itself; to withstand high temperatures; to be moisture-proof and inert to corrosive agencies; and not to "dry out" or become brittle over a long period of time. _Space Utilization_. The utilization of the winding space in an electromagnet is an important factor in design, since obviously the copper or other conductor is the only part of the winding that is effective in setting up magnetizing force. The space occupied by the insulation is, in this sense, waste space. An ideally perfect winding may be conceived as one in which the space is all occupied by wire; and this would necessarily involve the conception of wire of square cross-section and insulation of infinite thinness. In such a winding there would be no waste of space and a maximum amount of metal employed as a conductor. Of course, such a condition is not possible to attain and in practice some insulating material must be introduced between the layers of wire and between the adjacent convolutions of wire. The ratio of the space occupied by the conductor to the total space occupied by the winding, that is, by the conductor and the insulation, is called the _coefficient of space utilization of the coil_. For the ideal coil just conceived the coefficient of space utilization would be 1. Ordinarily the coefficient of space utilization is greater for coarse wire than for fine wire, since obviously the ratio of the diameter of the wire to the thickness of the insulation increases as the size of the wire grows larger. The chief advantage of enamel insulation for magnet wire is its thinness, and the high coefficient of space utilization which may be secured by its use. In good enamel wire the insulation will average about one-quarter the thickness of the standard single silk insulation, and the dielectric strength is equal or greater. Where economy of winding space is desirable the advantages of this may readily be seen. For instance, in a given coil wound with No. 36 single silk wire about one-half of the winding space is taken up with the insulation, whereas when the same coil is wound with No. 36 enameled wire only about one-fifth of the winding space is taken up by the insulation. Thus the coefficient of space utilization is increased from .50 to .80. The practical result of this is that, in the case of any given winding space where No. 36 wire is used, about 60 per cent more turns can be put on with enameled wire than with single silk insulation, and of course this ratio greatly increases when the comparison is made with double silk insulation or with cotton insulation. Again, where it is desired to reduce the winding space and keep the same number of turns, an equal number of turns may be had with a corresponding reduction of winding space where enameled wire is used in place of silk or cotton. In the matter of heat-resisting properties the enameled wire possesses a great advantage over silk and cotton. Cotton or silk insulation will char at about 260° Fahrenheit, while good enameled wire will stand 400° to 500° Fahrenheit without deterioration of the insulation. It is in the matter of liability to injury in rough or careless handling, or in winding coils having irregular shapes, that enamel wire is decidedly inferior to silk or cotton-covered wire. It is likely to be damaged if it is allowed to strike against the sharp corners of the magnet spool during winding, or run over the edge of a hard surface while it is being fed on to the spool. Coils having other than round cores, or having sharp corners on their spool heads, should not ordinarily be wound with enamel wire. The dielectric strength of enamel insulation is much greater than that of either silk or cotton insulation of equal thickness. This is a distinct advantage and frequently a combination of the two kinds of insulation results in a superior wire. If wire insulated with enamel is given a single wrapping of silk or of cotton, the insulating and dielectric properties of the enamel is secured, while the presence of the silk and cotton affords not only an additional safeguard against bare spots in the enamel but also a certain degree of mechanical protection to the enamel. Winding Methods. In winding a coil, the spool, after being properly prepared, is placed upon a spindle which may be made to revolve rapidly. Ordinarily the wire is guided on by hand; sometimes, however, machinery is used, the wire being run over a tool which moves to and fro along the length of the spool, just fast enough to lay the wire on at the proper rate. The movement of this tool is much the same as that of the tool in a screw cutting lathe. Unless high voltages are to be encountered, it is ordinarily not necessary to separate the layers of wire with paper, in the case of silk-or cotton-insulated magnet wire; although where especially high insulation resistance is needed this is often done. It is necessary to separate the successive layers of a magnet that is wound with enamel wire, by sheets of paper or thin oiled cloth. [Illustration: Fig. 99. Electromagnet with Bare Wire] In Fig. 99 is shown a method, that has been used with some success, of winding magnets with bare wire. In this the various adjacent turns are separated from each other by a fine thread of silk or cotton wound on beside the wire. Each layer of wire and thread as it is placed on the core is completely insulated from the subsequent layer by a layer of paper. This is essentially a machine-wound coil, and machines for winding it have been so perfected that several coils are wound simultaneously, the paper being fed in automatically at the end of each layer. Another method of winding the bare wire omits the silk thread and depends on the permanent positioning of the wire as it is placed on the coil, due to the slight sinking into the layer of paper on which it is wound. In this case the feed of the wire at each turn of the spool is slightly greater than the diameter of the wire, so that a small distance will be left between each pair of adjacent turns. Upon the completion of the winding of a coil, regardless of what method is used, it is customary to place a layer of bookbinders' cloth over the coil so as to afford a certain mechanical protection for the insulated wire. _Winding Terminals_. The matter of bringing out the terminal ends of the winding is one that has received a great deal of attention in the construction of electromagnets and coils for various purposes. Where the winding is of fine wire, it is always well to reinforce its ends by a short piece of larger wire. Where this is done the larger wire is given several turns around the body of the coil, so that the finer wire with which it connects may be relieved of all strain which may be exerted upon it from the protruding ends of the wire. Great care is necessary in the bringing out of the inner terminal--_i.e._, the terminal which connects with the inner layer--that the terminal wire shall not come in contact with any of the subsequent layers that are wound on. [Illustration Fig. 100. Electromagnet with Terminals] Where economy of space is necessary, a convenient method of terminating the winding of the coil consists in fastening rigid terminals to the spool head. This, in the case of a fiber spool head, may be done by driving heavy metal terminals into the fiber. The connections of the two wires leading from the winding are then made with these heavy rigid terminals by means of solder. A coil having such terminals is shown in its finished condition in Fig. 100. _Winding Data_. The two things principally affecting the manufacture of electromagnets for telephone purposes are _the number of turns in a winding_ and _the resistance of the wound wire_. The latter governs the amount of current which may flow through the coil with a given difference of potential at its end, while the former control the amount of magnetism produced in the core by the current flowing. While a coil is being wound, it is a simple matter to count the turns by any simple form of revolution counter. When the coil has been completed it is a simple matter to measure its resistance. But it is not so simple to determine in advance how many turns of a given size wire may be placed on a given spool, and still less simple to know what the resistance of the wire on that spool will be when the desired turns shall have been wound. TABLE IV Winding Data for Insulated Wires--Silk and Cotton Covering A.W.G. B & S | 20 21 22 23 24 25 --------------------------------------------------------------------- DIAMETER | Mils | 31.961 28.462 25.347 22.571 20.100 17.900 --------------------------------------------------------------------- AREA | Circular Mils | 1021.20 810.10 642.70 509.45 404.01 320.40 --------------------------------------------------------------------- DIAMETER OVER | INSULATION | SINGLE | COTTON | 37.861 34.362 31.247 28.471 26.000 23.800 | DOUBLE | COTTON | 42.161 38.662 35.547 32.771 30.300 28.100 | SINGLE SILK | 34.261 30.762 27.647 24,871 22.401 20.200 | DOUBLE SILK | 36.161 32.662 29.547 26.771 24.300 22.100 --------------------------------------------------------------------- TURNS PER | LINEAR INCH | SINGLE | COTTON | 25.7 28.3 31.0 34.4 36.9 38.0 | DOUBLE | 22.5 24.5 26.7 28.97 31.35 33.92 COTTON | | SINGLE SILK | 27.70 30.97 34.39 38.19 42.37 47.02 | DOUBLE SILK | 26.22 29.07 32.11 35.53 39.14 42.94 --------------------------------------------------------------------- TURNS PER | SQUARE INCH | SINGLE | COTTON | 660.5 800.9 961.0 1183.0 1321.6 1444.0 | DOUBLE | COTTON | 506.3 600.2 712.9 839.2 982.8 1150.8 | SINGLE SILK | 767.3 959.1 1182.7 1458.5 1795.2 2210.9 | DOUBLE SILK | 687.5 845.0 1031.0 1262.4 1532.0 1843.8 --------------------------------------------------------------------- OHMS PER | CUBIC INCH | SINGLE | COTTON | .646 .981 1.502 2.359 3.528 5.831 | DOUBLE | COTTON | .533 .795 1.188 1.772 2.595 3.802 | SINGLE SILK | .801 1.261 1.956 3.049 4.739 7.489 --------------------------------------------------------------------- A.W.G. B & S | 26 27 28 29 30 31 --------------------------------------------------------------------- DIAMETER | Mils | 15.940 14.195 12.641 11.257 10.025 8.928 --------------------------------------------------------------------- AREA | Circular Mils | 254.01 201.50 159.79 126.72 100.50 79.71 --------------------------------------------------------------------- DIAMETER OVER | INSULATION | SINGLE | COTTON | 21.840 20.095 18.541 17.157 15.925 14.828 | DOUBLE | COTTON | 26.140 24.395 22.841 21.457 20.225 19.128 | SINGLE SILK | 18.240 16.495 14.941 13.557 12.325 11.228 | DOUBLE SILK | 20.140 18.395 16.841 15.457 14.225 13.128 --------------------------------------------------------------------- TURNS PER | LINEAR INCH | SINGLE | COTTON | 42.0 48.0 53.0 56.5 59.66 64.125 | DOUBLE | COTTON | 36.29 38.95 41.61 44.27 46.93 49.78 | SINGLE SILK | 52.06 57.67 63.36 70.11 77.14 84.64 | DOUBLE SILK | 46.81 51.59 56.43 61.56 66.79 72.39 --------------------------------------------------------------------- TURNS PER | SQUARE INCH | SINGLE | COTTON | 1764.0 2304.0 2809.9 3192.3 3359.2 4112.2 | DOUBLE | COTTON | 1317.0 1517.2 1731.0 1959.9 2202.5 2478.0 | SINGLE SILK | 2710.3 3326.0 4014.5 4915.5 5950.2 7164.0 | DOUBLE SILK | 2191.2 2661.6 3184.5 3789.8 4461.0 5240.0 --------------------------------------------------------------------- OHMS PER | CUBIC INCH | SINGLE | COTTON | 6.941 10.814 17.617 25.500 34.800 48.5 | DOUBLE | COTTON | 5.552 8.078 11.54 16.47 23.43 32.83 | SINGLE SILK | 9.031 13.92 26.86 41.29 62.98 95.70 --------------------------------------------------------------------- A.W.G. B & S | 32 33 34 35 36 37 ---------------------------------------------------------------------- DIAMETER | Mils | 7.950 7.080 6.304 5.614 5.000 4.453 ---------------------------------------------------------------------- AREA | Circular Mils | 63.20 50.13 39.74 31.52 25.00 19.83 ---------------------------------------------------------------------- DIAMETER OVER | INSULATION | SINGLE | COTTON | 13.850 12.980 12.204 11.514 10.900 10.353 | DOUBLE | COTTON | 18.150 17.280 16.504 15.814 15.200 14.653 | SINGLE SILK | 10.250 9.380 8.504 7.914 7.300 6.753 | DOUBLE SILK | 12.150 11.280 10.504 9.814 9.200 8.653 ---------------------------------------------------------------------- TURNS PER | LINEAR INCH | SINGLE | COTTON | 68.600 73.050 77.900 82.600 87.100 91.870 | DOUBLE | COTTON | 52.34 55.10 57.57 60.04 62.51 64.70 | SINGLE SILK | 92.72 101.65 112.11 119.7 130.15 140.6 | DOUBLE SILK | 78.19 84.17 90.44 96.90 103.55 110.20 ---------------------------------------------------------------------- TURNS PER | SQUARE INCH | SINGLE | 4692.5 5333.5 6068.5 6773.3 7586.5 8440.0 COTTON | | DOUBLE | COTTON | 2739.5 3036.1 3314.2 3605.0 3907.5 4186.1 | SINGLE SILK | 8597.5 10332.0 12570.0 14327.0 16940.0 19770.0 | DOUBLE SILK | 6114.0 7085.0 8179.5 9389.5 10772.0 12145.0 --------------------------------------------------------------------- OHMS PER | CUBIC INCH | SINGLE | COTTON | 73.8 104.5 151.4 202.0 298.8 418.0 | DOUBLE | COTTON | 46.19 64.30 70.58 125.9 166.3 225.6 | SINGLE SILK | 144.70 217.8 342.1 489.0 721.1 1062.0 --------------------------------------------------------------------- A.W.G. B & S | 38 39 40 -------------------------------------------- DIAMETER | Mils | 3.965 3.531 3.144 -------------------------------------------- AREA | Circular Mils | 15.72 12.47 9.89 -------------------------------------------- DIAMETER OVER | INSULATION | SINGLE | COTTON | 9.865 9.431 9.044 | DOUBLE | COTTON | 14.165 13.731 13.344 | SINGLE SILK | 6.265 5.831 5.344 | DOUBLE SILK | 8.165 7.731 7.344 -------------------------------------------- TURNS PER | LINEAR INCH | SINGLE | COTTON | 95.000 100.700 106.000 | DOUBLE | COTTON | 66.80 68.80 71.20 | SINGLE SILK | 151.05 163.04 177.65 | DOUBLE SILK | 116.85 122.55 129.20 -------------------------------------------- TURNS PER | SQUARE INCH | SINGLE | COTTON | 9025.0 10140.5 11236.0 | DOUBLE | 4462.2 4733.6 5069.8 COTTON | | SINGLE SILK | 22820.0 26700.0 31559.0 | DOUBLE SILK | 13655.0 15018.0 16692.0 -------------------------------------------- OHMS PER | CUBIC INCH | SINGLE | COTTON | 567.0 811.0 1113.0 | DOUBLE | 305.5 409.8 545.5 COTTON | | SINGLE SILK | 1557.0 2266.0 3400.0 ------------------------------------------- If the length and the depth of the winding space of the coil as well as the diameter of the core are known, it is not difficult to determine how much bare copper wire of a given size may be wound on it, but it is more difficult to know these facts concerning copper wire which has been covered with cotton or silk. Yet something may be done, and tables have been prepared for standard wire sizes with definite thicknesses of silk and cotton insulation. As a result of facts collected from a large number of actually wound coils, the number of turns per linear inch and per square inch of B.&S. gauge wires from No. 20 to No. 40 have been tabulated, and these, supplemented by a tabulation of the number of ohms per cubic inch of winding space for wires of three different kinds of insulation, are given in Table IV. Bearing in mind that the calculations of Table IV are all based upon the "diameter over insulation," which it states at the outset for each of four different kinds of covering, it is evident what is meant by "turns per linear inch." The columns referring to "turns per square inch" mean the number of turns, the ends of which would be exposed in one square inch if the wound coil were cut in a plane passing through the axis of the core. Knowing the distance between the head, and the depth to which the coil is to be wound, it is easy to select a size of wire which will give the required number of turns in the provided space. It is to be noted that the depth of winding space is one-half of the difference between the core diameter and the complete diameter of the wound coil. The resistance of the entire volume of wound wire may be determined in advance by knowing the total cubic contents of the winding space and multiplying this by the ohms per cubic inch of the selected wire; that is, one must multiply in inches the distance between the heads of the spool by the difference between the squares of the diameters of the core and the winding space, and this in turn by .7854. This result, times the ohms per cubic inch, as given in the table, gives the resistance of the winding. There is a considerable variation in the method of applying silk insulation to the finer wires, and it is in the finer sizes that the errors, if any, pile up most rapidly. Yet the table throughout is based on data taken from many samples of actual coil winding by the present process of winding small coils. It should be said further that the table does not take into account the placing of any layers of paper between the successive layers of the wires. This table has been compared with many examples and has been used in calculating windings in advance, and is found to be as close an approximation as is afforded by any of the formulas on the subject, and with the further advantage that it is not so cumbersome to apply. _Winding Calculations._ In experimental work, involving the winding of coils, it is frequently necessary to try one winding to determine its effect in a given circuit arrangement, and from the knowledge so gained to substitute another just fitted to the conditions. It is in such a substitution that the table is of most value. Assume a case in which are required a spool and core of a given size with a winding of, say No. 25 single silk-covered wire, of a resistance of 50 ohms. Assume also that the circuit regulations required that this spool should be rewound so as to have a resistance of, say 1,000 ohms. What size single silk-covered wire shall be used? Manifestly, the winding space remains the same, or nearly so. The resistance is to be increased from 50 to 1,000 ohms, or twenty times its first value. Therefore, the wire to be used must show in the table twenty times as many ohms per cubic inch as are shown in No. 25, the known first size. This amount would be twenty times 7.489, which is 149.8, but there is no size giving this exact resistance. No. 32, however, is very nearly of that resistance and if wound to exactly the same depth would give about 970 ohms. A few turns more would provide the additional thirty ohms. Similarly, in a coil known to possess a certain number of turns, the table will give the size to be selected for rewinding to a greater or smaller number of turns. In this case, as in the case of substituting a winding of different resistance, it is unnecessary to measure and calculate upon the dimensions of the spool and core. Assume a spool wound with No. 30 double silk-covered wire, which requires to be wound with a size to double the number of turns. The exact size to do this would have 8922. turns per square inch and would be between No. 34 and No. 35. A choice of these two wires may be made, using an increased winding depth with the smaller wire and a shallower winding depth for the larger wire. Impedance Coils. In telephony electromagnets frequently serve, as already stated, to perform other functions than the producing of motion by attracting or releasing their armatures. They are required to act as impedance coils to present a barrier to the passage of alternating or other rapidly fluctuating currents, and at the same time to allow the comparatively free passage of steady currents. Where it is desired that an electromagnet coil shall possess high impedance, it is usual to employ a laminated instead of a solid core. This is done by building up a core of suitable size by laying together thin sheets of soft iron, or by forming a bundle of soft iron wires. The use of laminated cores is for the purpose of preventing eddy currents, which, if allowed to flow, would not only be wasteful of energy but would also tend to defeat the desired high impedance. Sometimes in iron-clad impedance coils, the iron shell is slotted longitudinally to break up the flow of eddy currents in the shell. Frequently electromagnetic coils have only the function of offering impedance, where no requirements exist for converting any part of the electric energy into mechanical work. Where this is the case, such coils are termed _impedance_, or _retardation_, or _choke coils_, since they are employed to impede or to retard or to choke back the flow of rapidly varying current. The distinction, therefore, between an impedance coil and the coil of an ordinary electromagnet is one of function, since structurally they may be the same, and the same principles of design and construction apply largely to each. _Number of Turns_. It should be remembered that an impedance coil obstructs the passage of fluctuating current, not so much by ohmic resistance as by offering an opposing or counter-electromotive force. Other things being equal, the counter-electromotive force of self-induction increases directly as the number of turns on a coil and directly as the number of lines of force threading the coil, and this latter factor depends also on the reluctance of the magnetic circuit. Therefore, to secure high impedance we need many turns or low reluctance, or both. Often, owing to requirements for direct-current carrying capacity and limitations of space, a very large number of turns is not permissible, in which case sufficiently high impedance to such rapid fluctuations as those of voice currents may be had by employing a magnetic circuit of very low reluctance, usually a completely closed circuit. _Kind of Iron. _An important factor in the design of impedance coils is the grade of iron used in the magnetic circuit. Obviously, it should be of the highest permeability and, furthermore, there should be ample cross-section of core to prevent even an approach to saturation. The iron should, if possible, be worked at that density of magnetization at which it has the highest permeability in order to obtain the maximum impedance effects. _Types._ Open-Circuit:--Where very feeble currents are being dealt with, and particularly where there is no flow of direct current, an open magnetic circuit is much used. An impedance coil having an open magnetic circuit is shown in section in Fig. 101, Fig. 102 showing its external appearance and illustrating particularly the method of bringing out the terminals of the winding. [Illustration: Fig. 101. Section of Open-Circuit Impedance Coil] [Illustration: Fig. 102. Open-Circuit Impedance Coil] [Illustration: Fig. 103. Closed-Circuit Impedance Coil] Closed-Circuit:--A type of retardation coil which is largely used in systems of simultaneous telegraphy and telephony, known as _composite systems_, is shown in Fig. 103. In the construction of this coil the core is made of a bundle of fine iron wires first bent into U-shape, and then after the coils are in place, the free ends of the core are brought together to form a closed magnetic circuit. The coils have a large number of turns of rather coarse wire. The conditions surrounding the use of this coil are those which require very high impedance and rather large current-carrying capacity, and fortunately the added requirement, that it shall be placed in a very small space, does not exist. Toroidal:--Another type of retardation coil, called the toroidal type due to the fact that its core is a torus formed by winding a continuous length of fine iron wire, is shown in diagram in Fig. 104. The two windings of this coil may be connected in series to form in effect a single winding, or it may be used as a "split-winding" coil, the two windings being in series but having some other element, such as a battery, connected between them in the circuit. Evidently such a coil, however connected, is well adapted for high impedance, on account of the low reluctance of its core. [Illustration: Fig. 104. Symbol of Toroidal Impedance Coil] This coil is usually mounted on a base-board, the coil being enclosed in a protecting iron case, as shown in Fig. 105. The terminal wires of both windings of each coil are brought out to terminal punchings on one end of the base-board to facilitate the making of the necessary circuit connections. [Illustration: Fig. 105. Toroidal Impedance Coil] The usual diagrammatic symbol for an impedance coil is shown in Fig. 106. This is the same as for an ordinary bar magnet, except that the parallel lines through the core may be taken as indicating that the core is laminated, thus conveying the idea of high impedance. The symbol of Fig. 104 is a good one for the toroidal type of impedance coil. [Illustration: Fig. 106. Symbol of Impedance Coil] Induction Coil. An induction coil consists of two or more windings of wire interlinked by a common magnetic circuit. In an induction coil having two windings, any change in the strength of the current flowing in one of the windings, called the _primary_, will cause corresponding changes in the magnetic flux threading the magnetic circuit, and, therefore, changes in flux through the other winding, called the _secondary_. This, by the laws of electromagnetic induction, will produce corresponding electromotive forces in the secondary winding and, therefore, corresponding currents in that winding if its circuit be closed. _Current and Voltage Ratios._ In a well-designed induction coil the energy in the secondary, _i.e._, the induced current, is for all practical purposes equal to that of the primary current, yet the values of the voltage and the amperage of the induced current may vary widely from the values of the voltage and the amperage of the primary current. With simple periodic currents, such as the commercial alternating lighting currents, the ratio between the voltage in the primary and that in the secondary will be equal to the ratio of the number of turns in the primary to the number of turns in the secondary. Since the energy in the two circuits will be practically the same, it follows _that the ratio between the current in the primary and that in the secondary will be equal to the ratio of the number of turns in the secondary to the number of turns in the primary_. In telephony, where the currents are not simple periodic currents, and where the variations in current strength take place at different rates, such a law as that just stated does not hold for all cases; but it may be stated in general that _the induced currents will be of higher voltage and smaller current strength than those of the primary in all coils where the secondary winding has a greater number of turns than the primary_, and _vice versâ_. _Functions._ The function of the induction coil in telephony is, therefore, mainly one of transformation, that is, either of stepping up the voltage of a current, or in other cases stepping it down. The induction coil, however, does serve another purpose in cases where no change in voltage and current strength is desired, that is, it serves as a means for electrically separating two circuits so far as any conductive relation exists, and yet of allowing the free transmission by induction from one of these circuits to the other. This is a function that in telephony is scarcely of less importance than the purely transforming function. _Design._ Induction coils, as employed in telephony, may be divided into two general types: first, those having an open magnetic circuit; and, second, those having a closed magnetic circuit. In the design of either type it is important that the core should be thoroughly laminated, and this is done usually by forming it of a bundle of soft Swedish or Norway iron wire about .02 of an inch in diameter. The diameter and the length of the coil, and the relation between the number of turns in the primary and in the secondary, and the mechanical construction of the coil, are all matters which are subject to very wide variation in practice. While the proper relationship of these factors is of great importance, yet they may not be readily determined except by actual experiment with various coils, owing to the extreme complexity of the action which takes place in them and to the difficulty of obtaining fundamental data as to the existing facts. It may be stated, therefore, that the design of induction coils is nearly always carried out by "cut-and-try" methods, bringing to bear, of course, such scientific and practical knowledge as the experimenter may possess. [Illustration: Fig. 107. Induction Coil] [Illustration: Fig. 108. Section of Induction Coil] _Use and Advantage._ The use and advantages of the induction coil in so-called local-battery telephone sets have already been explained in previous chapters. Such induction coils are nearly always of the open magnetic circuit type, consisting of a long, straight core comprised of a bundle of small annealed iron wires, on which is wound a primary of comparatively coarse wire and having a small number of turns, and over which is wound a secondary of comparatively fine wire and having a very much larger number of turns. A view of such a coil mounted on a base is shown in Fig. 107, and a sectional view of a similar coil is shown in Fig. 108. The method of bringing out the winding terminals is clearly indicated in this figure, the terminal wires _2_ and _4_ being those of the primary winding and _1_ and _3_ those of the secondary winding. It is customary to bring out these wires and attach them by solder to suitable terminal clips. In the case of the coil shown in Fig. 108 these clips are mounted on the wooden heads of the coil, while in the design shown in Fig. 107 they are mounted on the base, as is clearly indicated. Repeating Coil. The so-called repeating coil used in telephony is really nothing but an induction coil. It is used in a variety of ways and usually has for its purpose the inductive association of two circuits that are conductively separated. Usually the repeating coil has a one to one ratio of turns, that is, there are the same number of turns in the primary as in the secondary. However, this is not always the case, since sometimes they are made to have an unequal number of turns, in which case they are called _step-up _or _step-down_ repeating coils, according to whether the primary has a smaller or a greater number of turns than the secondary. Repeating coils are almost universally of the closed magnetic circuit type. _Ringing and Talking Considerations._ Since repeating coils often serve to connect two telephones, it follows that it is sometimes necessary to ring through them as well as talk through them. By this is meant that it is necessary that the coil shall be so designed as to be capable of transforming the heavy ringing currents as well as the very much smaller telephone or voice currents. Ringing currents ordinarily have a frequency ranging from about 16 to 75 cycles per second, while voice currents have frequencies ranging from a few hundred up to perhaps ten thousand per second. Ordinarily, therefore, the best form of repeating coil for transforming voice currents is not the best for transforming the heavy ringing currents and _vice versâ_. If the comparatively heavy ringing currents alone were to be considered, the repeating coil might well be of heavy construction with a large amount of iron in its magnetic circuit. On the other hand, for carrying voice currents alone it is usually made with a small amount of iron and with small windings, in order to prevent waste of energy in the core, and to give a high degree of responsiveness with the least amount of distortion of wave form, so that the voice currents will retain as far as possible their original characteristics. When, therefore, a coil is required to carry both ringing and talking currents, a compromise must be effected. _Types._ The form of repeating coil largely used for both ringing and talking through is shown in Fig. 109. This coil comprises a soft iron core made up of a bundle of wires about .02 inch in diameter, the ends of which are left of sufficient length to be bent back around the windings after they are in place and thus form a completely closed magnetic path for the core. The windings of this particular coil are four in number, and contain about 2,400 turns each, and have a resistance of about 60 ohms. In this coil, when connected for local battery work, the windings are connected in pairs in series, thus forming effectively two windings having about 120 ohms resistance each. The whole coil is enclosed in a protecting case of iron. The terminals are brought out to suitable clips on the wooden base, as shown. An external perspective view of this coil is shown in Fig. 110. By bringing out each terminal of each winding, eight in all, as shown in this figure, great latitude of connection is provided for, since the windings may be connected in circuit in any desirable way, either by connecting them together in pairs to form virtually a primary and a secondary, or, as is frequently the case, to split the primary and the secondary, connecting a battery between each pair of windings. [Illustration: Fig. 109. Repeating Coil] [Illustration: Fig. 110. Repeating Coil] Fig. 111 illustrates in section a commercial type of coil designed for talking through only. This coil is provided with four windings of 1,357 turns each, and when used for local battery work the coils are connected in pairs in series, thus giving a resistance of about 190 ohms in each half of the repeating coil. The core of this coil consists of a bundle of soft iron wires, and the shell which forms the return path for the magnetic lines is of very soft sheet iron. This shell is drawn into cup shape and its open end is closed, after the coil is inserted, by the insertion of a soft iron head, as indicated. As in the case of the coil shown in Figs. 109 and 110, eight terminals are brought out on this coil, thus providing the necessary flexibility of connection. [Illustration: Fig. 111. Repeating Coil] [Illustration: Fig. 112. Diagram of Toroidal Repeating Coil] [Illustration: Fig. 113. Toroidal Repeating Coil] Still another type of repeating coil is illustrated in diagram in Fig. 112, and in view in Fig. 113. This coil, like the impedance coil shown in Fig. 104, comprises a core made up of a bundle of soft iron wires wound into the form of a ring. It is usually provided with two primary windings placed opposite each other upon the core, and with two secondary windings, one over each primary. In practice these two primary windings are connected in one circuit and the two secondaries in another. This is the standard repeating coil now used by the Bell companies in their common-battery cord circuits. [Illustration: THE OPERATING ROOM OF THE EXCHANGE AT WEBB CITY, MISSOURI] [Illustration: Fig. 114. Symbol of Induction Coil] Conventional Symbols. The ordinary symbol for the induction coil used in local battery work is shown in Fig. 114. This consists merely of a pair of parallel zig-zag lines. The primary winding is usually indicated by a heavy line having a fewer number of zig-zags, and the secondary by a finer line having a greater number of zig-zags. In this way the fact that the primary is of large wire and of comparatively few turns is indicated. This diagrammatic symbol may be modified to suit almost any conditions, and where a tertiary as well as a secondary winding is provided it may be shown by merely adding another zig-zag line. [Illustration: Fig. 115. Repeating-Coil Symbols] The repeating coil is indicated symbolically in the two diagrams of Fig. 115. Where there is no necessity for indicating the internal connections of the coil, the symbol shown in the left of this figure is usually employed. Where, however, the coil consists of four windings rather than two and the method of connecting them is to be indicated, the symbol at the right hand is employed. In Fig. 116 another way of indicating a four-winding repeating coil or induction coil is shown. Sometimes such windings may be combined by connection to form merely a primary and a secondary winding, and in other cases the four windings all act separately, in which case one may be considered the primary and the others, respectively, the secondary, tertiary, and quaternary. [Illustration: Fig. 116. Symbol of Four-Winding Repeating Coil] Where the toroidal type of repeating coil is employed, the diagram of Fig. 112, already referred to, is a good symbolic representation. CHAPTER XI NON-INDUCTIVE RESISTANCE DEVICES It is often desired to introduce simple ohmic resistance into telephone circuits, in order to limit the current flow, or to create specific differences of potential at given points in the circuit. Temperature Coefficient. The design or selection of resistance devices for various purposes frequently involves the consideration of the effect of temperature on the resistance of the conductor employed. The resistance of conductors is subject to change by changes in temperature. While nearly all metals show an increase, carbon shows a decrease in its resistance when heated. The temperature coefficient of a conductor is a factor by which the resistance of the conductor at a given temperature must be multiplied in order to determine the change in resistance of that conductor brought about by a rise in temperature of one degree. TABLE V Temperature Coefficients +---------------------------+-----------------------------+ | PURE METALS | TEMPERATURE COEFFICIENTS | +---------------------------+--------------+--------------+ | | CENTIGRADE | FAHRENHEIT | +---------------------------+--------------+--------------+ | Silver (annealed) | 0.00400 | 0.00222 | | Copper (annealed) | 0.00428 | 0.00242 | | Gold (99.9%) | 0.00377 | 0.00210 | | Aluminum (99%) | 0.00423 | 0.00235 | | Zinc | 0.00406 | 0.00226 | | Platinum (annealed) | 0.00247 | 0.00137 | | Iron | 0.00625 | 0.00347 | | Nickel | 0.0062 | 0.00345 | | Tin | 0.00440 | 0.00245 | | Lead | 0.00411 | 0.00228 | | Antimony | 0.00389 | 0.00216 | | Mercury | 0.00072 | 0.00044 | | Bismuth | 0.00354 | 0.00197 | +---------------------------+--------------+--------------+ _Positive and Negative Coefficients._ Those conductors, in which a rise in temperature produces an increase in resistance, are said to have positive temperature coefficients, while those in which a rise in temperature produces a lowering of resistance are said to have negative temperature coefficients. The temperature coefficients of pure metals are always positive and for some of the more familiar metals, have values, according to Foster, as in Table V. Iron, it will be noticed, has the highest temperature coefficient of all. Carbon, on the other hand, has a large negative coefficient, as proved by the fact that the filament of an ordinary incandescent lamp has nearly twice the resistance when cold as when heated to full candle-power. Certain alloys have been produced which have very low temperature coefficients, and these are of value in producing resistance units which have practically the same resistance for all ordinary temperatures. Some of these alloys also have very high resistance as compared with copper and are of value in enabling one to obtain a high resistance in small space. One of the most valuable resistance wires is of an alloy known as _German silver_. The so-called eighteen per cent alloy has approximately 18.3 times the resistance of copper and a temperature coefficient of .00016 per degree Fahrenheit. The thirty per cent alloy has approximately 28 times the resistance of copper and a temperature coefficient of .00024 per degree Fahrenheit. For facilitating the design of resistance coils of German silver wire, Tables VI and VII are given, containing information as to length, resistance, and weight of the eighteen per cent and the thirty per cent alloys, respectively, for all sizes of wire smaller than No. 20 B. & S. gauge. Special resistance alloys may be obtained having temperature coefficients as low as .000003 per degree Fahrenheit. Other alloys of nickel and steel are adapted for use where the wire must carry heavy currents and be raised to comparatively high temperatures thereby; for such use non-corrosive properties are specially to be desired. Such wire may be obtained having a resistance of about fifty times that of copper. TABLE VI 18 Per Cent German Silver Wire +---------+----------+-----------------+----------------+---------------+ | No. | | | | | | B. & S. | DIAMETER | WEIGHT | LENGTH | RESISTANCE | | GAUGE | INCHES | POUNDS PER FOOT | FEET PER POUND | OHMS PER FOOT | +---------+----------+-----------------+----------------+---------------+ | 21 | .02846 | .002389 | 418.6 | .2333 | | 22 | .02535 | .001894 | 527.9 | .2941 | | 23 | .02257 | .001502 | 665.8 | .3710 | | 24 | .02010 | .001191 | 839.5 | .4678 | | 25 | .01790 | .0009449 | 1058. | .5899 | | 26 | .01594 | .0007493 | 1335. | .7438 | | 27 | .01419 | .0005943 | 1683. | .9386 | | 28 | .01264 | .0004711 | 2123. | 1.183 | | 29 | .01126 | .0003735 | 2677. | 1.491 | | 30 | .01003 | .0002962 | 3376. | 1.879 | | 31 | .008928 | .0002350 | 4255. | 2.371 | | 32 | .007950 | .0001864 | 5366. | 2.990 | | 33 | .007080 | .0001478 | 6766. | 3.771 | | 34 | .006304 | .0001172 | 8532. | 4.756 | | 35 | .005614 | .00009295 | 10758. | 5.997 | | 36 | .005000 | .00007369 | 13569. | 7.560 | | 37 | .004453 | .00005845 | 17108. | 9.532 | | 38 | .003965 | .00004636 | 21569. | 12.02 | | 39 | .003531 | .00003675 | 27209. | 15.16 | | 40 | .003145 | .00002917 | 34282. | 19.11 | +---------+----------+-----------------+----------------+---------------+ Inductive Neutrality. Where the resistance unit is required to be strictly non-inductive, and is to be in the form of a coil, special designs must be employed to give the desired inductive neutrality. Provisions Against Heating. In cases where a considerable amount of heat is to be generated in the resistance, due to the necessity of carrying large currents, special precautions must be taken as to the heat-resisting properties of the structure, and also as to the provision of sufficient radiating surface or its equivalent to provide for the dissipation of the heat generated. Types. _Mica Card Unit._ One of the most common resistance coils used in practice is shown in Fig. 117. This comprises a coil of fine, bare German silver wire wound on a card of mica, the windings being so spaced that the loops are not in contact with each other. The winding is protected by two cards of mica and the whole is bound in place by metal strips, to which the ends of the winding are attached. Binding posts are provided on the extended portions of the terminals to assist in mounting the resistance on a supporting frame, and the posts terminate in soldering terminals by which the resistance is connected into the circuit. TABLE VII 30 Per Cent German Silver Wire +---------+----------+-----------------+----------------+---------------+ | No. | | | | | | B. & S. | DIAMETER | WEIGHT | LENGTH | RESISTANCE | | GAUGE | INCHES | POUNDS PER FOOT | FEET PER POUND | OHMS PER FOOT | +---------+----------+-----------------+----------------+---------------+ | 21 | .02846 | .002405 | 415.8 | .3581 | | 22 | .02535 | .001907 | 524.4 | .4513 | | 23 | .02257 | .001512 | 661.3 | .5693 | | 24 | .02010 | .001199 | 833.9 | .7178 | | 25 | .01790 | .0009513 | 1051. | .9051 | | 26 | .01594 | .0007544 | 1326. | 1.141 | | 27 | .01419 | .0005983 | 1671. | 1.440 | | 28 | .01264 | .0004743 | 2108. | 1.815 | | 29 | .01126 | .0003761 | 2659. | 2.287 | | 30 | .01003 | .0002982 | 3353. | 2.883 | | 31 | .008928 | .0002366 | 4227. | 3.638 | | 32 | .007950 | .0001876 | 5330. | 4.588 | | 33 | .007080 | .0001488 | 6721. | 5.786 | | 34 | .006304 | .0001180 | 8475. | 7.297 | | 35 | .005614 | .00009358 | 10686. | 9.201 | | 36 | .005000 | .00007419 | 13478. | 11.60 | | 37 | .004453 | .00005885 | 16994. | 14.63 | | 38 | .003965 | .00004668 | 21424. | 18.45 | | 39 | .003531 | .00003700 | 27026. | 23.26 | | 40 | .003145 | .00002937 | 34053. | 29.32 | +---------+----------+-----------------+----------------+---------------+ _Differentially-Wound Unit._ Another type of resistance coil is that in which the winding is placed upon an insulating core of heat-resisting material and wound so as to overcome inductive effects. In order to accomplish this, the wire to be bound on the core is doubled back on itself at its middle portion to form two strands, and these are wound simultaneously on the core, thus forming two spirals of equal number of turns. The current in traversing the entire coil must flow through one spiral in one direction with relation to the core, and in the opposite direction in the other spiral, thereby nullifying the inductive effects of one spiral by those of the other. This is called a _non-inductive winding_ and is in reality an example of differential winding. _Lamp Filament._ An excellent type of non-inductive resistance is the ordinary carbon-filament incandescent lamp. This is used largely in the circuits of batteries, generators, and other sources of supply to prevent overload in case of short circuits on the line. These are cheap, durable, have large current-carrying capacities, and are not likely to set things afire when overheated. An additional advantage incident to their use for this purpose is that an overload on a circuit in which they are placed is visibly indicated by the glowing of the lamp. [Illustration: Fig. 117. Mica Card Resistance] [Illustration: Fig. 118. Iron-Wire Ballast] Obviously, the carbon-filament incandescent lamp, when used as a resistance, has, on account of the negative temperature coefficient of carbon, the property of presenting the highest resistance to the circuit when carrying no current, and of presenting a lower and lower resistance as the current and consequent heating increases. For some conditions of practice this is not to be desired, and the opposite characteristic of presenting low resistance to small currents and comparatively high resistance to large currents would best meet the conditions of practice. _Iron-Wire Ballast._ Claude D. Enochs took advantage of the very high positive temperature coefficient of iron to produce a resistance device having these characteristics. His arrangement possesses the compactness of the carbon-filament lamp and is shown in Fig. 118. The resistance element proper is an iron wire, wound on a central stem of glass, and this is included in an exhausted bulb so as to avoid oxidation. Such a resistance is comparatively low when cold, but when traversed by currents sufficient to heat it considerably will offer a very large increase of resistance to oppose the further increase of current. In a sense, it is a self-adjusting resistance, tending towards the equalization of the flow of current in the circuit in which it is placed. CHAPTER XII CONDENSERS Charge. A conducting body insulated from all other bodies will receive and hold a certain amount of electricity (a charge), if subjected to an electrical potential. Thus, referring to Fig. 119, if a metal plate, insulated from other bodies, be connected with, say, the positive pole of a battery, the negative pole of which is grounded, a current will flow into the plate until the plate is raised to the same potential as that of the battery pole to which it is connected. The amount of electricity that will flow into the plate will depend, other things being equal, on the potential of the source from which it is charged; in fact, it is proportional to the potential of the source from which it is charged. This amount of electricity is a measure of the capacity of the plate, just as the amount of water that a bath-tub will hold is a measure of the capacity of the bath-tub. Capacity. Instead of measuring the amount of electricity by the quart or pound, as in the case of material things, the unit of electrical quantity is the _coulomb_. The unit of capacity of an insulated conductor is the _farad_, and a given insulated conductor is said to have unit capacity, that is, the capacity of one farad, when it will receive a charge of one coulomb of electricity at a potential of one volt. Referring to Fig. 119, the potential of the negative terminal of the battery may be said to be zero, since it is connected to the earth. If the battery shown be supposed to have exactly one volt potential, then the plate would be said to have the capacity of one farad if one coulomb of electricity flowed from the battery to the plate before the plate was raised to the same potential as that of the positive pole, that is, to a potential of one volt above the potential of the earth; it being assumed that the plate was also at zero potential before the connection was made. Another conception of this quantity may be had by remembering that a coulomb is such a quantity of current as will result from one ampere flowing one second. The capacity of a conductor depends, among other things, on its area. If the plate of Fig. 119 should be made twice as large in area, other things remaining the same, it would have twice the capacity. But there are other factors governing the capacity of a conductor. Consider the diagram of Fig. 120, which is supposed to represent two such plates as are shown in Fig. 119, placed opposite each other and connected respectively with the positive and the negative poles of the battery. When the connection between the plates and the battery is made, the two plates become charged to a difference of potential equal to the electromotive force of the battery. In order to obtain these charges, assume that the plates were each at zero potential before the connection was made; then current flows from the battery into the plates until they each assume the potential of the corresponding battery terminal. If the two plates be brought closer together, it will be found that more current will now flow into each of them, although the difference of potential between the two plates must obviously remain the same, since each of them is still connected to the battery. [Illustration: Fig. 119. Condenser Plate] Theory. Due to the proximity of the plates, the positive electricity on plate _A_ is drawn by the negative charge on plate _B_ towards plate _B_, and likewise the negative electricity on plate _B_ is drawn to the side towards plate _A_ by the positive charge on that plate. These two charges so drawn towards each other will, so to speak, bind each other, and they are referred to as _bound charges_. The charge on the right-hand side of plate _A_ and on the left-hand side of plate _B_ will, however, be free charges, since there is nothing to attract them, and these are, therefore, neutralized by a further flow of electricity from the battery to the plate. [Illustration: Fig. 120. Theory of Condenser] Obviously, the closer together the plates are the stronger will be the attractive influence of the two charges on each other. From this it follows that in the case of plate _A_, when the two plates are being moved closer together, more positive electricity will flow into plate _A_ to neutralize the increasing free negative charges on the right-hand side of the plate. As the plates are moved closer together still, a new distribution of charges will take place, resulting in more positive electricity flowing into plate _A_ and more negative electricity flowing into plate _B_. The closer proximity of the plates, therefore, increases the capacity of the plates for holding charges, due to the increased inductive action across the dielectric separating the plates. Condenser Defined. A condenser is a device consisting of two adjacent plates of conducting material, separated by an insulating material, called a _dielectric_. The purpose is to increase by the proximity of the plates, each to the other, the amount of electricity which each plate will receive and hold when subjected to a given potential. Dielectric. We have already seen that the capacity of a condenser depends upon the area of its plates, and also upon their distance apart. There is still another factor on which the capacity of a condenser depends, _i.e._, on the character of the insulating medium separating its plates. The inductive action which takes place between a charged conductor and other conductors nearby it, as between plate _A_ and plate _B_ of Fig. 120, is called _electrostatic induction_, and it plays an important part in telephony. It is found that the ability of a given charged conductor to induce charges on other neighboring conductors varies largely with the insulating medium or dielectric that separates them. This quality of a dielectric, by which it enables inductive action to take place between two separated conductors, is called _inductive capacity_. Usually this quality of dielectrics is measured in terms of the same quality in dry air, this being taken as unity. When so expressed, it is termed _specific inductive capacity_. To be more accurate the specific inductive capacity of a dielectric is the ratio between the capacity of a condenser having that substance as a dielectric, to the capacity of the same condenser using dry air at zero degrees Centigrade and at a pressure of 14.7 pounds per square inch as the dielectric. To illustrate, if two condensers having plates of equal size and equal distance apart are constructed, one using air as the dielectric and the other using hard crown glass as the dielectric, the one using glass will have a capacity of 6.96 times that of the one using air. From this we say that crown glass has a specific inductive capacity of 6.96. Various authorities differ rather widely as to the specific inductive capacity of many common substances. The values given in Table VIII have been chosen from the Smithsonian Physical Tables. TABLE VIII Specific Inductive Capacities +-----------------------+------------------------+ |DIELECTRIC | REFERRED TO AIR AS 1 | +-----------------------+------------------------+ |Vacuum | .99941 | |Hydrogen | .99967 | |Carbonic Acid | 1.00036 | |Dry Paper | 1.25 to 1.75 | |Paraffin | 1.95 to 2.32 | |Ebonite | 1.9 to 3.48 | |Sulphur | 2.24 to 3.90 | |Shellac | 2.95 to 3.73 | |Gutta-percha | 3.3 to 4.9 | |Plate Glass | 3.31 to 7.5 | |Porcelain | 4.38 | |Mica | 4.6 to 8.0 | |Glass--Light Flint | 6.61 | |Glass--Hard Crown | 6.96 | |Selenium | 10.2 | +-----------------------+------------------------+ This data is interesting as showing the wide divergence in specific inductive capacities of various materials, and also showing the wide divergence in different observations of the same material. Undoubtedly, this latter is due mainly to the fact that various materials differ largely in themselves, as in the case of paraffin, for instance, which exhibits widely different specific inductive capacities according to the difference in rapidity with which it is cooled in changing from a liquid to a solid state. We see then that the capacity of a condenser varies as the area of its plates, as the specific inductive capacity of the dielectric employed, and also inversely as the distance between the plates. Obviously, therefore, in making a condenser of large capacity, it is important to have as large an area of the plate as possible; to have them as close together as possible; to have the dielectric a good insulating medium so that there will be practically no leakage between the plates; and to have the dielectric of as high a specific inductive capacity as economy and suitability of material in other respects will permit. Dielectric Materials. _Mica_. Of all dielectrics mica is the most suitable for condensers, since it has very high insulation resistance and also high specific inductive capacity, and furthermore may be obtained in very thin sheets. High-grade condensers, such as are used for measurements and standardization purposes, usually have mica for the dielectric. [Illustration: Fig. 121. Rolled Condenser] _Dry Paper. _The demands of telephonic practice are, however, such as to require condensers of very cheap construction with large capacity in a small space. For this purpose thin bond paper, saturated with paraffin, has been found to be the best dielectric. The conductors in condensers are almost always of tinfoil, this being an ideal material on account of its cheapness and its thinness. Before telephony made such urgent demands for a cheap compact condenser, the customary way of making them was to lay up alternate sheets of dielectric material, either of oiled paper or mica and tinfoil, the sheets of tinfoil being cut somewhat smaller than the sheets of dielectric material in order that the proper insulation might be secured at the edges. After a sufficient number of such plates were built up the alternate sheets of tinfoil were connected together to form one composite plate of the condenser, while the other sheets were similarly connected together to form the other plate. Obviously, in this way a very large area of plates could be secured with a minimum degree of separation. [Illustration: Fig. 122. Rolled Condenser] There has been developed for use in telephony, however, and its use has since extended into other arts requiring condensers, what is called the _rolled condenser_. This is formed by rolling together in a flat roll four sheets of thin bond paper, _1_, _2_, _3_, and _4_, and two somewhat narrower strips of tinfoil, _5_ and _6_, Fig. 121. The strips of tinfoil and paper are fed on to the roll in continuous lengths and in such manner that two sheets of paper will lie between the two strips of tinfoil in all cases. Thin sheet metal terminals _7_ and _8_ are rolled into the condenser as it is being wound, and as these project beyond the edges of the paper they form convenient terminals for the condenser after it is finished. After it is rolled, the roll is boiled in hot paraffin so as to thoroughly impregnate it and expel all moisture. It is then squeezed in a press and allowed to cool while under pressure. In this way the surplus paraffin is expelled and the plates are brought very close together. It then appears as in Fig. 122. The condenser is now sealed in a metallic case, usually rectangular in form, and presents the appearance shown in Fig. 123. [Illustration: Fig. 123. Rolled Condenser] A later method of condenser making which has not yet been thoroughly proven in practice, but which bids fair to produce good results, varies from the method just described in that a paper is used which in itself is coated with a very thin conducting material. This conducting material is of metallic nature and in reality forms a part of the paper. To form a condenser of this the sheets are merely rolled together and then boiled in paraffin and compressed as before. Sizes. The condensers ordinarily used in telephone practice range in capacity from about 1/4 microfarad to 2 microfarads. When larger capacities than 2 microfarads are desired, they may be obtained by connecting several of the smaller size condensers in multiple. Table IX gives the capacity, shape, and dimensions of a variety of condensers selected from those regularly on the market. TABLE IX Condenser Data +------------+---------------+---------------------------------+ | | | DIMENSIONS IN INCHES | | CAPACITY | SHAPE |----------+----------+-----------+ | | | Height | Width | Thickness | +------------+---------------+----------+----------+-----------+ | 2 m. f. | Rectangular | 9-1/6 | 4-3/4 | 11/16 | | 1 m. f. | " | 9-1/6 | 4-3/4 | 11/16 | | 1 m. f. | " | 4-3/4 | 2-3/32 | 13/16 | | 1/2 m. f. | " | 2-3/4 | 1-1/4 | 3/4 | | 1 m. f. | " | 4-13/16 | 2-1/32 | 25/32 | | 1/2 m. f. | " | 4-3/4 | 2-3/32 | 13/16 | | 3/10 m. f. | " | 4-3/4 | 2-3/32 | 13/16 | | 1 m. f. | " | 2-3/4 | 3 | l | +------------+---------------+----------+----------+-----------+ Conventional Symbols. The conventional symbols usually employed to represent condensers in telephone diagrams are shown in Fig. 124. These all convey the idea of the adjacent conducting plates separated by insulating material. [Illustration: Fig. 124. Condenser Symbols] Functions. Obviously, when placed in a circuit a condenser offers a complete barrier to the flow of direct current, since no conducting path exists between its terminals, the dielectric offering a very high insulation resistance. If, however, the condenser is connected across the terminals of a source of alternating current, this current flows first in one direction and then in the other, the electromotive force in the circuit increasing from zero to a maximum in one direction, and then decreasing back to zero and to a maximum in the other direction, and so on. With a condenser connected so as to be subjected to such alternating electromotive forces, as the electromotive force begins to rise the electromotive force at the condenser terminals will also rise and a current will, therefore, flow into the condenser. When the electromotive force reaches its maximum, the condenser will have received its full charge for that potential, and the current flow into it will cease. When the electromotive force begins to fall, the condenser can no longer retain its charge and a current will, therefore, flow out of it. Apparently, therefore, there is a flow of current through the condenser the same as if it were a conductor. Means for Assorting Currents. In conclusion, it is obvious that the telephone engineer has within his reach in the various coils--whether non-inductive or inductive, or whether having one or several windings--and in the condenser, a variety of tools by which he may achieve a great many useful ends in his circuit work. Obviously, the condenser affords a means for transmitting voice currents or fluctuating currents, and for excluding steady currents. Likewise the impedance coil affords a means for readily transmitting steady currents but practically excluding voice currents or fluctuating currents. By the use of these very simple devices it is possible to sift out the voice currents from a circuit containing both steady and fluctuating currents, or it is possible in the same manner to sift out the steady currents and to leave the voice currents alone to traverse the circuit. Great use is made in the design of telephone circuits of the fact that the electromagnets, which accomplish the useful mechanical results in causing the movement of parts, possess the quality of impedance. Thus, the magnets which operate various signaling relays at the central office are often used also as impedance coils in portions of the circuit through which it is desired to have only steady currents pass. If, on the other hand, it is necessary to place a relay magnet, having considerable impedance, directly in a talking circuit, the bad effects of this on the voice currents may be eliminated by shunting this coil with a condenser, or with a comparatively high non-inductive resistance. The voice currents will flow around the high impedance of the relay coil through the condenser or resistance, while the steady currents, which are the ones which must be depended upon to operate the relay, are still forced in whole or in part to pass through the relay coil where they belong. In a similar way the induction coil affords a means for keeping two circuits completely isolated so far as the direct flow of current between them is concerned, and yet of readily transmitting, by electromagnetic induction, currents from one of these circuits to the other. Here is a means of isolation so far as direct current is concerned, with complete communication for alternating current. CHAPTER XIII CURRENT SUPPLY TO TRANSMITTERS The methods by which current is supplied to the transmitter of a telephone for energizing it, may be classified under two divisions: first, those where the battery or other source of current is located at the station with the transmitter which it supplies; and second, those where the battery or other source of current is located at a distant point from the transmitter, the battery in such cases serving as a common source of current for the supply of transmitters at a number of stations. The advantages of putting the transmitter and the battery which supplies it with current in a local circuit with the primary of an induction coil, and placing the secondary of the induction coil in the line, have already been pointed out but may be briefly summarized as follows: When the transmitter is placed directly in the _line circuit_ and the line is of considerable length, the current which passes through the transmitter is necessarily rather small unless a battery of high potential is used; and, furthermore, the total change in resistance which the transmitter is capable of producing is but a small proportion of the total resistance of the line, and, therefore, the current changes produced by the transmitter are relatively small. On the other hand, when the transmitter is placed in a _local circuit_ with the battery, this circuit may be of small resistance and the current relatively large, even though supplied by a low-voltage battery; so that the transmitter is capable of producing relatively large changes in a relatively large current. To draw a comparison between these two general classes of transmitter current supply, a number of cases will be considered in connection with the following figures, in each of which two stations connected by a telephone line are shown. Brief reference to the local battery method of supplying current will be made in order to make this chapter contain, as far as possible, all of the commonly used methods of current supply to transmitters. [Illustration: A TYPICAL MEDIUM-SIZED MULTIPLE SWITCHBOARD EQUIPMENT] Local Battery. In Fig. 125 two stations are shown connected by a grounded line wire. The transmitter of each station is included in a low-resistance primary circuit including a battery and the primary winding of an induction coil, the relation between the primary circuits and the line circuits being established by the inductive action between the primary and the secondary windings of induction coils, the secondary in each case being in the line circuits with the receivers. [Illustration: Fig. 125. Local-Battery Stations with Grounded Circuit] Fig. 126 shows exactly the same arrangement but with a metallic circuit rather than a grounded circuit. The student should become accustomed to the replacing of one of the line wires of a metallic circuit by the earth, and to the method, employed in Figs. 125 and 126, of indicating a grounded circuit as distinguished from a metallic circuit. [Illustration: Fig. 126. Local-Battery Stations with Metallic Circuit] In Fig. 127 is shown a slight modification of the circuit shown in Fig. 126, which consists of connecting one end of the primary winding to one end of the secondary winding of the induction coil, thus linking together the primary circuit and the line circuit, a portion of each of these circuits being common to a short piece of the local wiring. There is no difference whatever in the action of the circuits shown in Figs. 126 and 127, the latter being shown merely for the purpose of bringing out this fact. It is very common, particularly in local-battery circuits, to connect one end of the primary and the secondary windings, as by doing so it is often possible to save a contact point in the hook switch and also to simplify the wiring. [Illustration: Fig. 127. Local-Battery Stations with Metallic Circuit] The advantages to be gained by employing a local battery at each subscriber's station associated with the transmitter in the primary circuit of an induction coil are attended by certain disadvantages from a commercial standpoint. The primary battery is not an economical way to generate electric energy. In all its commercial forms it involves the consumption of zinc and zinc is an expensive fuel. The actual amount of current in watts required by a telephone is small, however, and this disadvantage due to the inexpensive method of generating current would not in itself be of great importance. A more serious objection to the use of local batteries at subscribers' stations appears when the subject is considered from the standpoint of maintenance. Batteries, whether of the so-called "dry" or "wet" type, gradually deteriorate, even when not used, and in cases where the telephone is used many times a day the deterioration is comparatively rapid. This makes necessary the occasional renewals of the batteries with the attendant expense for new batteries or new material, and of labor and transportation in visiting the station. The labor item becomes more serious when the stations are scattered in a sparsely settled community, in which case the visiting of the stations, even for the performance of a task that would require but a few minutes' time, may consume some hours on the part of the employes in getting there and back. Common Battery. _Advantages._ It would be more economical if all of the current for the subscribers' transmitters could be supplied from a single comparatively efficient generating source instead of from a multitude of inefficient small sources scattered throughout the community served by the exchange. The advantage of such centralization lies not only in more economic generating means, but also in having the common source of current located at one place, where it may be cared for with a minimum amount of expense. Such considerations have resulted in the so-called "common-battery system," wherein the current for all the subscribers' transmitters is furnished from a source located at the central office. Where such a method of supplying current is practiced, the result has also been, in nearly all cases, the doing away with the subscriber's magneto generators, relying on the central-office source of current to furnish the energy for enabling the subscriber to signal the operator. Such systems, therefore, concentrate all of the sources of energy at the central office and for that reason they are frequently referred to as central-energy systems. NOTE. In this chapter the central-energy or common-battery system will be considered only in so far as the supply of current for energizing the subscribers' transmitters is concerned, the discussion of the action of signaling being reserved for subsequent chapters. _Series Battery._ If but a single pair of lines had to be considered, the arrangement shown in Fig. 128 might be employed. In this the battery is located at the central office and placed in series with the two grounded lines leading from the central office to the two subscribers' stations. The voltage of this battery is made sufficient to furnish the required current over the resistance of the entire line circuit with its included instruments. Obviously, changes in resistance in the transmitter at Station A will affect the flow of current in the entire line and the fluctuations resulting from the vibration of the transmitter diaphragm will, therefore, reproduce these sounds in the receiver at Station B, as well as in that at Station A. [Illustration: Fig. 128. Battery in Series with Two Lines] An exactly similar arrangement applied to a metallic circuit is shown in Fig. 129. In thus placing the battery in series in the circuit between the two stations, as shown in Figs. 128 and 129, it is obvious that the transmitter at each station is compelled to vary the resistance of the entire circuit comprising the two lines in series, in order to affect the receiver at distant stations. This is in effect making the transmitter circuit twice as long as is necessary, as will be shown in the subsequent systems considered. Furthermore, the placing of the battery in series in the circuit of the two combined lines does not lend itself readily to the supply of current from a common source to more than a single pair of lines. [Illustration: Fig. 129. Battery in Series with Two Lines] _Series Substation Circuit._ The arrangement at the substations--consisting in placing the transmitter and the receiver in series in the line circuit, as shown in Figs. 128 and 129--is the simplest possible one, and has been used to a considerable extent, but it has been subject to the serious objection, where receivers having permanent magnets were used, of making it necessary to so connect the receiver in the line circuit that the steady current from the battery would not set up a magnetization in the cores of the receiver in such a direction as to neutralize or oppose the magnetization of the permanent magnets. As long as the current flowed through the receiver coils in such a direction as to supplement the magnetization of the permanent magnets, no harm was usually done, but when the current flowed through the receiver coils in such a way as to neutralize or oppose the magnetizing force of the permanent magnets, the action of the receiver was greatly interfered with. As a result, it was necessary to always connect the receivers in the line circuit in a certain way, and this operation was called _poling_. In order to obviate the necessity for poling and also to bring about other desirable features, it has been, until recently, almost universal practice to so arrange the receiver that it would be in the circuit of the voice currents passing over the line, but would not be traversed by direct currents, this condition being brought about by various arrangements of condensers, impedance coils, or induction coils, as will be shown later. During the year 1909, however, the adoption by several concerns of the so-called "direct-current" receiver has made it necessary for the direct current to flow through the receiver coils in order to give the proper magnetization to the receiver cores, and this has brought about a return to the very simple form of substation circuit, which includes the receiver and the transmitter directly in the circuit of the line. This illustrates well an occurrence that is frequently observed by those who have opportunity to watch closely the development of an art. At one time the conditions will be such as to call for complicated arrangements, and for years the aim of inventors will be to perfect these arrangements; then, after they are perfected, adopted, and standardized, a new idea, or a slight alteration in the practice in some other respect, will demand a return to the first principles and wipe out the necessity for the things that have been so arduously striven for. [Illustration: Fig. 130. Bridging Battery with Repeating Coil] _Bridging Battery with Repeating Coil._ As pointed out, the placing of the battery in series in the line circuit in the central office is not desirable, and, so far as we are aware, has never been extensively used. The universal practice, therefore, is to place it in a bridge path across the line circuit, and a number of arrangements employing this basic idea are in wide use. In Fig. 130 is shown the standard arrangement of the Western Electric Company, employed by practically all the Bell operating companies. In this the battery at the central office is connected in the middle of the two sides of a repeating coil so that the current from the battery is fed out to the two connected lines in multiple. Referring to the middle portion of this figure showing the central-office apparatus, _1_ and _2_ may be considered as the two halves of one side of a repeating coil divided so that the battery may be cut into their circuit. Likewise, _3_ and _4_ may be considered as the two halves of the other side of the repeating coil similarly divided for the same purpose. The windings of this repeating coil are ordinarily alike; that is, _1_ and _2_ combined have the same resistance, number of turns, and impedance as _3_ and _4_ combined. The two sides of this coil are alternately used as primary and secondary, _1_ and _2_ forming the primary when Station A is talking, and _3_ and _4_, the secondary; and _vice versâ_ when Station B is talking. As will be seen, the current flowing from the positive pole of the battery will divide and flow through the windings _2_ and _4_; thence over the upper limb of each line, through the transmitter at each station, and back over the lower limbs of the line, through the windings _1_ and _3_, where the two paths reunite and pass to the negative pole of the battery. It is evident that when neither transmitter is being used the current flowing through both lines will be a steady current and that, therefore, neither line will have an inductive effect on the other. When, however, the transmitter at Station A is used the variations in the resistance caused by it will cause undulations in the current. These undulations, passing through the windings _1_ and _2_ of the repeating coil, will cause, by electromagnetic induction, alternating currents to flow in the windings _3_ and _4_, and these alternating currents will be superimposed on the steady currents flowing in that line and will affect the receiver at Station B, as will be pointed out. The reverse conditions exist when Station B is talking. _Bell Substation Arrangement._ The substation circuits at the stations in Fig. 130 are illustrative of one of the commonly employed methods of preventing the steady current from the battery from flowing through the receiver coil. This particular arrangement is that employed by the common-battery instruments of the various Bell companies. Considering the action at Station B, it is evident that the steady current will pass through the transmitter and through the secondary winding of the induction coil, and that as long as this current is steady no current will flow through the telephone receiver. The receiver, transmitter, and primary winding of the induction coil are, however, included in a local circuit with the condenser. The presence of the condenser precludes the possibility of direct current flowing in this path. Considering Station A as a receiving station, it is evident that the voice currents coming to the station over the line will pass through the secondary winding and will induce alternating currents in the primary winding which will circulate through the local circuit containing the receiver and the condenser, and thus actuate the receiver. The considerations are not so simple when the station is being treated as a transmitting station. Under this condition the steady current passes through the transmitter in an obvious manner. It is clear that if the local circuit containing the receiver did not exist, the circuit would be operative as a transmitting circuit because the transmitter would produce fluctuations in the steady current flowing in the line and thus be able to affect the distant station. The transmitter, therefore, has a direct action on the currents flowing in the line by the variation in resistance which it produces in the line circuit. There is, however, a subsidiary action in this circuit. Obviously, there is a drop of potential across the transmitter terminals due to the flow of steady current. This means that the upper terminal of the condenser will be charged to the same potential as the upper terminal of the transmitter, while the lower terminal of the condenser will be of the same potential as the lower terminal of the transmitter. When, now, the transmitter varies its resistance, a variation in the potential across its terminals will occur; and as a result, a variation in potential across the terminals of the condenser will occur, and this means that alternating currents will flow through the primary winding of the induction coil. The transmitter, therefore, by its action, causes alternating currents to flow through the primary of this induction coil and it causes, by direct action on the circuit of the line, fluctuations in the steady current flowing in the line. The alternating currents flowing in the primary of the coil induce currents in the secondary of the coil which supplement and augment the fluctuations produced by the direct action of the transmitter. This circuit may be looked at, therefore, in the light of combining the direct action which the transmitter produces in the current in the line with the action which the transmitter produces in the local circuit containing the primary of the induction coil, this action being repeated in the line circuit through the secondary of the induction coil. The receiver in this circuit is placed in the local circuit, and is thus not traversed by the steady currents flowing in the line. There is thus no necessity for poling it. This circuit is very efficient, but is subject to the objection of producing a heavy side tone in the receiver of the transmitting station. By "side tone" is meant the noises which are produced in the receiver at a station by virtue of the action of the transmitter at that station. Side tone is objectionable for several reasons: first, it is sometimes annoying to the subscriber; second, and of more importance, the subscriber who is talking, hearing a very loud noise in his own receiver, unconsciously assumes that he is talking too loud and, therefore, lowers his voice, sometimes to such an extent that it will not properly reach the distant station. [Illustration: Fig. 131. Bridging Battery with Impedance Coils] _Bridging Battery with Impedance Coils._ The method of feeding current to the line from the common battery, shown in Fig. 130, is called the "split repeating-coil" method. As distinguished from this is the impedance-coil method which is shown in Fig. 131. In this the battery is bridged across the circuit of the combined lines in series with two impedance coils, _1_ and _2_, one on each side of the battery. The steady currents from the battery find ready path through these impedance coils which are of comparatively low ohmic resistance, and the current divides and passes in multiple over the circuits of the two lines. Voice currents, however, originating at either one of the stations, will not pass through the shunt across the line at the central office on account of the high impedance offered by these coils, and as a result they are compelled to pass on to the distant station and affect the receiver there, as desired. This impedance-coil method seems to present the advantage of greater simplicity over the repeating-coil method shown in Fig. 130, and so far as talking efficiency is concerned, there is little to choose between the two. The repeating-coil method, however, has the advantage over this impedance-coil method, because by it the two lines are practically divided except by the inductive connection between the two windings, and as a result an unbalanced condition of one of the connected lines is not as likely to produce an unbalanced condition in the other as where the two lines are connected straight through, as with the impedance-coil method. The substation arrangement of Fig. 131 is the same as that of Fig. 130. [Illustration: Fig. 132. Double-Battery Kellogg System] _Double Battery with Impedance Coils._ A modification of the impedance-coil method is used in all of the central-office work of the Kellogg Switchboard and Supply Company. This employs a combination of impedance coils and condensers, and in effect isolates the lines conductively from each other as completely as the repeating-coil method. It is characteristic of all the Kellogg common-battery systems that they employ two batteries instead of one, one of these being connected in all cases with the calling line of a pair of connected lines and the other in all cases with the called line. As shown in Fig. 132, the left-hand battery is connected with the line leading to Station A through the impedance coils _1_ and _2_. Likewise, the right-hand battery is connected to the line of Station B through the impedance coils _3_ and _4_. These four impedance coils are wound on separate cores and do not have any inductive relation whatsoever with each other. Condensers _5_ and _6_ are employed to completely isolate the lines conductively. Current from the left-hand battery, therefore, passes only to Station A, and current from the right-hand battery to Station B. Whenever the transmitter at Station A is actuated the undulations of current which it produces in the line cause a varying difference of potential across the outside terminals of the two impedance coils _1_ and _2_. This means that the two left-hand terminals of condensers _5_ and _6_ are subjected to a varying difference of potential and these, of course, by electrostatic induction, cause the right-hand terminals of these condensers to be subject to a correspondingly varying difference of potential. From this it follows that alternating currents will be impressed upon the right-hand line and these will affect the receiver at Station B. A rough way of expressing the action of this circuit is to consider it in the same light as that of the impedance-coil circuit shown in Fig. 131, and to consider that the voice currents originating in one line are prevented from passing through the bridge paths at the central office on account of the impedance, and are, therefore, forced to continue on the line, being allowed to pass readily by the condensers in series between the two lines. _Kellogg Substation Arrangement._ An interesting form of substation circuit which is employed by the Kellogg Company in all of its common-battery telephones is shown in Fig. 132. In passing, it may be well to state that almost any of the substation circuits shown in this chapter are capable of working with any of the central-office circuits. The different ones are shown for the purpose of giving a knowledge of the various substation circuits that are employed, and, as far as possible, to associate them with the particular central-office arrangements with which they are commonly used. In this Kellogg substation arrangement the line circuit passes first through the transmitter and then divides, one branch passing through an impedance coil _7_ and the other through the receiver and the condenser _8_, in series. The steady current from the central-office battery finds ready path through the transmitter and the impedance coil, but is prevented from passing through the receiver by the barrier set up by the condenser _8_. Voice currents, however, coming over the line to the station, find ready path through the receiver and the condenser but are barred from passing through the impedance coil by virtue of its high impedance. In considering the action of the station as a transmitting station, the variations set up by the transmitter pass through the condenser and the receiver at the same station, while the steady current which supplies the transmitter passes through the impedance coil. Impedance coils used for this purpose are made of low ohmic resistance but of a comparatively great number of turns, and, therefore, present a good path for steady currents and a difficult path for voice currents. This divided circuit arrangement employed by the Kellogg Company is one of the very simple ways of eliminating direct currents from the receiver path, at the same time allowing the free passage of voice currents. [Illustration: Fig. 133. Dean System] _Dean Substation Arrangement._ In marked contrast to the scheme for keeping steady current out of the receiver circuit employed by the Kellogg Company, is that shown in Fig. 133, which has been largely used by the Dean Electric Company, of Elyria, Ohio. The central-office arrangement in this case is that using the split repeating coil, which needs no further description. The substation arrangement, however, is unique and is a beautiful example of what can be done in the way of preventing a flow of current through a path without in any way insulating that path or placing any barrier in the way of the current. It is an example of the prevention of the direct flow of current through the receiver by so arranging the circuits that there will always be an equal potential on each side of it, and, therefore, no tendency for current to flow through it. In this substation arrangement four coils of wire--_1_, _2_, _3_, and _4_--are so arranged as to be connected in the circuit of the line, two in series and two in multiple. The current flowing from the battery at the central office, after passing through the transmitter, divides between the two paths containing, respectively, the coils _1_ and _3_ and the coils _2_ and _4_. The receiver is connected between the junction of the coils _2_ and _4_ and that of _1_ and _3_. The resistances of the coils are so chosen that the drop of potential through the coil _2_ will be equal to that through the coil _1_, and likewise that through the coil _4_ will be equal to that through the coil _3_. As a result, the receiver will be connected between two points of equal potential, and no direct current will flow through it. How, then, do voice currents find their way through the receiver, as they evidently must, if the circuit is to fulfill any useful function? The coils _2_ and _3_ are made to have high impedance, while _1_ and _4_ are so wound as to be non-inductive and, therefore, offer no impedance save that of their ohmic resistance. What is true, therefore, of direct currents does not hold for voice currents, and as a result, the voice currents, instead of taking the divided path which the direct currents pursued, are debarred from the coils _2_ and _3_ by their high impedance and thus pass through the non-inductive coil _1_, the receiver, and the non-inductive coil _4_. This circuit employs a Wheatstone-bridge arrangement, adjusted to a state of balance with respect to direct currents, such currents being excluded from the receiver, not because the receiver circuit is in any sense opaque to such direct currents, but because there is no difference of potential between the terminals of the receiver circuit, and, therefore, no tendency for current to flow through the receiver. In order that fluctuating currents may not, for the same reason, be caused to pass by, rather than through, the receiver circuit, the diametrically-opposed arms of the Wheatstone bridge are made to possess, in large degree, self-induction, thereby giving these two arms a high impedance to fluctuating currents. The conditions which exist for direct currents do not, therefore, exist for fluctuating currents, and it is this distinction which allows alternating currents to pass through the receiver and at the same time excludes direct currents therefrom. In practice, the coils _1_, _2_, _3_, and _4_ of the Dean substation circuit are wound on the same core, but coils _1_ and _4_--the non-inductive ones--are wound by doubling the wire back on itself so as to neutralize their self-induction. _Stromberg-Carlson._ Another modification of the central-office arrangement and also of the subscribers' station circuits, is shown in Fig. 134, this being a simplified representation of the circuits commonly employed by the Stromberg-Carlson Telephone Manufacturing Company. The battery feed at the central office differs only from that shown in Fig. 132, in that a single battery rather than two batteries is used, the current being supplied to one of the lines through the impedance coils _1_ and _2_, and to the other line through the impedance coils _3_ and _4_; condensers _5_ and _6_ serve conductively to isolate the two lines. At the subscriber's station the line circuit passes through the secondary of an induction coil and the transmitter. The receiver is kept entirely in a local circuit so that there is no tendency for direct current to flow through it, but it is receptive to voice currents through the electromagnetic induction between the primary and the secondary of the induction coil. [Illustration: Fig. 134. Stromberg-Carlson System] [Illustration: Fig. 135. North Electric Company System] _North._ Another arrangement of central-office battery feed is employed by the North Electric Company, and is shown in Fig. 135. In this two batteries are used which supply current respectively to the two connected lines, condensers being employed to conductively isolate the lines. This differs from the Kellogg arrangement shown in Fig. 132 in that the two coils _1_ and _2_ are wound on the same core, while the coils _3_ and _4_ are wound together upon another core. In this case, in order that the inductive action of one of the coils may not neutralize that of the other coil on the same core, the two coils are wound in such relative direction that their magnetizing influence will always be cumulative rather than differential. The central-office arrangements discussed in Figs. 130 to 135, inclusive, are those which are in principal use in commercial practice in common-battery exchanges. _Current Supply over Limbs of Line in Parallel._ As indicating further interesting possibilities in the method of supplying current from a common source to a number of substations, several other systems will be briefly referred to as being of interest, although these have not gone into wide commercial use. The system shown in Fig. 136 is one proposed by Dean in the early days of common-battery working, and this arrangement was put into actual service and gave satisfactory results, but was afterwards supplanted by the Bell equipment operating under the system shown in Fig. 130, which became standardized by that company. In this the current from the common battery at the central office is not fed over the two line wires in series, but in multiple, using a ground return from the subscriber's station to the central office. Across the metallic circuit formed by two connected lines there is bridged, at the central office, an impedance coil _1_, and between the center point of this impedance coil and the ground is connected the common battery. At the subscriber's station is placed an impedance coil _2_, also bridged across the two limbs of the line, and between the center point of this impedance coil and the ground is connected the transmitter, which is shunted by the primary winding of an induction coil. Connected between the two limbs of the line at the substation there is also the receiver and the secondary of an induction coil in series. [Illustration: Fig. 136. Current Supply over Parallel Limbs of Line] The action of this circuit at first seems a little complex, but if taken step by step may readily be understood. The transmitter supply circuit may be traced from the central-office battery through the two halves of the impedance coil _1_ in multiple; thence over the two limbs of the line in multiple to Station A, for instance; thence in multiple through the two halves of impedance coil _2_, to the center point of that coil; thence through the two paths offered respectively by the primary of the induction coil and by the transmitter; then to ground and back to the other pole of the central-office battery. By this circuit the transmitter at the substation is supplied with current. Variations in the resistance of the transmitter when in action, cause complementary variations in the supply current flowing through the primary of the induction coil. These variations induce similar alternating currents in the secondary of this coil, which is in series in the line circuit. The currents, so induced in this secondary, flow in series through one side of the line to the distant station; thence through the secondary and the receiver at that station to the other side of the line and back through that side of the line to the receiver. These currents are not permitted to pass through the bridged paths across the metallic circuit that are offered by the impedance coils _1_ and _2_, because they are voice currents and are, therefore, debarred from these paths by virtue of the impedance. [Illustration: Fig. 137. Current Supply over Parallel Limbs of Line] An objection to this form of current supply and to other similar forms, wherein the transmitter current is fed over the two sides of the line in multiple with a ground return, is that the ground-return circuit formed by the two sides of the line in multiple is subject to inductive disturbances from other lines in the same way as an ordinary grounded line is subject to inductive disturbance. The current-supply circuit is thus subject to external disturbances and such disturbances find their way into the metallic circuit and, therefore, through the instruments by means of the electromagnetic induction between the primary and the secondary coils at the substations. Another interesting method of current supply from a central-office battery is shown in Fig. 137. This, like the circuit just considered, feeds the energy to the subscriber's station over the two sides of the line in multiple with a ground return. In this case, however, a local circuit is provided at the substation, in which is placed a storage battery _1_ and the primary _2_ of an induction coil, together with the transmitter. The idea in this is that the current supply from the central office will pass through the storage battery and charge it. Upon the use of the transmitter, this storage battery acts to supply current to the local circuit containing the transmitter and the primary coil _2_ in exactly the same manner as in a local battery system. The fluctuating current so produced by the action of the transmitter in this local circuit acts on the secondary winding _3_ of the induction coil, and produces therein alternating currents which pass to the central office and are in turn repeated to the distant station. _Supply Many Lines from Common Source._ We come now to the consideration of the arrangement by which a single battery may be made to supply current at the central office to a large number of pairs of connected lines simultaneously. Up to this point in this discussion it has been shown only how each battery served a single pair of connected lines and no others. Repeating Coil:--In Fig. 138 is shown how a single battery supplies current simultaneously to four different pairs of lines, the lines of each pair being connected for conversation. It is seen that the pairs of lines shown in this figure are arranged in each case in accordance with the system shown in Fig. 130. Let us inquire why it is that, although all of these four pairs of lines are connected with a common source of energy and are, therefore, all conductively joined, the stations will be able to communicate in pairs without interference between the pairs. In other words, why is it that voice currents originating at Station A will pass only to the receiver at Station B and not to the receivers at Station C or Station H, for instance? The reason is that separate supply conductors lead from the points such as _1_ and _2_ at the junctions of the repeating-coil windings on each pair of circuits to the battery terminals, and the resistance and impedance of the battery itself and of the common leads to it are so small that although the feeble voice currents originating in the pair of lines connecting Station A and Station B pass through the battery, they are not able to alter the potential of the battery in any appreciable degree. As a result, therefore, the supply wires leading from the common-battery terminals to the points _7_ and _8_, for instance, cannot be subjected to any variations in potential by virtue of currents flowing through the battery from the points _1_ and _2_ of the lines joining Station A and Station B. [Illustration: MAIN OFFICE, KEYSTONE TELEPHONE COMPANY, PHILADELPHIA, PA.] [Illustration: Fig. 138. Common Source for Many Lines] [Illustration: Fig. 139. Common Source for Many Lines] Retardation Coil--Single Battery:--In Fig. 139 is shown in similar manner the current supply from a single battery to four different pairs of lines, the battery being associated with the lines by the combined impedance coil and condenser method, which was specifically dealt with in connection with Fig. 133. The reasons why there will be no interference between the conversations carried on in the various pairs of connected lines in this case are the same as those just considered in connection with the system shown in Fig. 138. The impedance coils in this case serve to keep the telephone currents confined to their respective pairs of lines in which they originate, and this same consideration applies to the system of Fig. 138, for each of the separate repeating-coil windings of Fig. 138 is in itself an impedance coil with respect to such currents as might leak away from one pair of lines on to another. Retardation Coil--Double Battery:--The arrangement of feeding a number of pairs of lines according to the Kellogg two-battery system is indicated in Fig. 140, which needs no further explanation in view of the description of the preceding figures. It is interesting to note in this case that the left-hand battery serves only the left-hand lines and the right-hand battery only the right-hand lines. As this is worked out in practice, the left-hand battery is always connected to those lines which originate a call and the right-hand battery always to those lines that are called for. The energy supplied to a calling line is always, therefore, from a different source than that which supplies a called line. [Illustration: Fig. 140. Two Sources for Many Lines] [Illustration: Fig. 141. Current Supply from Distant Point] _Current Supply from Distant Point._ Sometimes it is convenient to supply current to a group of lines centering at a certain point from a source of current located at a distant point. This is often the case in the so-called private branch exchange, where a given business house or other institution is provided with its own switchboard for interconnecting the lines leading to the various telephones of that concern or institution among themselves, and also for connecting them with lines leading to the city exchange. It is not always easy or convenient to maintain at such private switchboards a separate battery for supplying the current needed by the local exchange. In such cases the arrangement shown in Fig. 141 is sometimes employed. This shows two pairs of lines connected by the impedance-coil system with common terminals _1_ and _2_, between which ordinarily the common battery would be connected. Instead of putting a battery between these terminals, however, at the local exchange, a condenser of large capacity is connected between them and from these terminals circuit wires _3_ and _4_ are led to a battery of suitable voltage at a distant central office. The condenser in this case is used to afford a short-circuit path for the voice currents that leak from one side of one pair of lines to the other, through the impedance coils bridged across the line. In this way the effect of the necessarily high resistance in the common leads _3_ and _4_, leading to the storage battery, is overcome and the tendency to cross-talk between the various pairs of connected lines is eliminated. Frequently, instead of employing this arrangement, a storage battery of small capacity will be connected between the terminals _1_ and _2_, instead of the condenser, and these will be charged over the wires _3_ and _4_ from a source of current at a distant point. A consideration of the various methods of supplying current from a common source to a number of lines will show that it is essential that the resistance of the battery itself be very low. It is also necessary that the resistance and the impedance of the common leads from the battery to the point of distribution to the various pairs of lines be very low, in order that the voice currents which flow through them, by virtue of the conversations going on in the different pairs of lines, shall not produce any appreciable alteration in the difference of potential between the battery terminals. CHAPTER XIV THE TELEPHONE SET We have considered what may be called the elemental parts of a complete telephone; that is, the receiver, transmitter, hook switch, battery, generator, call bell, condenser, and the various kinds of coils which go to make up the apparatus by which one is enabled to transmit and receive speech and signals. We will now consider the grouping of these various elements into a complete working organization known as a telephone. Before considering the various types it is well to state that the term telephone is often rather loosely used. We sometimes hear the receiver proper called a telephone or a hand telephone. Since this was the original speaking telephone, there is some reason for so calling the receiver. The modern custom more often applies the term telephone to the complete organization of talking and signaling apparatus, together with the associated wiring and cabinet or standard on which it is mounted. The name telephone set is perhaps to be preferred to the word telephone, since it tends to avoid misunderstanding as to exactly what is meant. Frequently, also, the telephone or telephone set is referred to as a subscriber's station equipment, indicating the equipment that is to be found at a subscriber's station. This, as applying to a telephone alone, is not proper, since the subscriber's station equipment includes more than a telephone. It includes the local wiring within the premises of the subscriber and also the lightning arrester and other protective devices, if such exist. To avoid confusion, therefore, the collection of talking and signaling apparatus with its wiring and containing cabinet or standard will be referred to in this work as a telephone or telephone set. The receiver will, as a rule, be designated as such, rather than as a telephone. The term subscriber's station equipment will refer to the complete equipment at a subscriber's station, and will include the telephone set, the interior wiring, and the protective devices, together with any other apparatus that may be associated with the telephone line and be located within the subscriber's premises. Classification of Sets. Telephones may be classified under two general headings, magneto telephones and common-battery telephones, according to the character of the systems in which they are adapted to work. _Magneto Telephone._ The term magneto telephone, as it was originally employed in telephony, referred to the type of instrument now known as a receiver, particularly when this was used also as a transmitter. As the use of this instrument as a transmitter has practically ceased, the term magneto telephone has lost its significance as applying to the receiver, and, since many telephones are equipped with magneto generators for calling purposes, the term magneto telephone has, by common consent, come to be used to designate any telephone including, as a part of its equipment, a magneto generator. Magneto telephones usually, also, include local batteries for furnishing the transmitter with current, and this has led to these telephones being frequently called local battery telephones. However, a local battery telephone is not necessarily a magneto telephone and _vice versâ_, since sometimes magneto telephones have no local batteries and sometimes local battery telephones have no magnetos. Nearly all of the telephones which are equipped with magneto generators are, however, also equipped with local batteries for talking purposes, and, therefore, the terms magneto telephone and local battery telephone usually refer to the same thing. _Common-Battery Telephone._ Common-battery telephones, on the other hand, are those which have no local battery and no magneto generator, all the current for both talking and signaling being furnished from a common source of current at the central office. _Wall and Desk Telephones._ Again we may classify telephones or telephone sets in accordance with the manner in which their various parts are associated with each other for use, regardless of what parts are contained in the set. We may refer to all sets adapted to be mounted on a wall or partition as _wall telephones_, and to all in which the receiver, transmitter, and hook are provided with a standard of their own to enable them to rest on any flat surface, such as a desk or table, as _desk telephones_. These latter are also referred to as portable telephones and as portable desk telephones. In general, magneto or local battery telephones differ from common-battery telephones in their component parts, the difference residing principally in the fact that the magneto telephone always has a magneto generator and usually a local battery, while the common-battery telephone has no local source of current whatever. On the other hand, the differences between wall telephones and desk telephones are principally structural, and obviously either of these types of telephones may be for common-battery or magneto work. The same component parts go to make up a desk telephone as a wall telephone, provided the two instruments are adapted for the same class of service, but the difference between the two lies in the structural features by which these same parts are associated with each other and protected from exposure. [Illustration: Fig. 142. Magneto Wall Set] [Illustration: Fig. 143. Magneto Wall Set] Magneto-Telephone Sets. _Wall._ In Fig. 142 is shown a familiar type of wall set. The containing box includes within it all of the working parts of the apparatus except that which is necessarily left outside in order to be within the reach of the user. Fig. 143 shows the same set with the door open. This gives a good idea of the ordinary arrangement of the apparatus within. It is seen that the polarized bell or ringer has its working parts mounted on the inside of the door or cover of the box, the tapper projecting through so as to play between the gongs on the outside. Likewise the transmitter arm, which supports the transmitter and allows its adjustment up and down to accommodate itself to the height of the user, is mounted on the front of the door, and the conductors leading to it may be seen fastened to the rear of the door in Fig. 143. In some wall sets the wires leading to the bell and transmitter are connected to the wiring of the rest of the set through the hinges of the door, thus allowing the door to be opened and closed repeatedly without breaking off the wires. In order to always insure positive electrical contact between the stationary and movable parts of the hinge a small wire is wound around the hinge pin, one end being soldered to the stationary part and the other end to the movable part of the hinge. In other forms of wall set the wires to the bell and the transmitter lead directly from the stationary portion of the cabinet to the back of the door, the wires being left long enough to have sufficient flexibility to allow the door to be opened and closed without injuring the wires. At the upper portion of the box there is mounted the hook switch, this being, in this case, of the short lever type. The lever of the hook projects through the side of the box so as to make the hook available as a support for the receiver. Immediately at the right of the hook switch is mounted the induction coil, and immediately below this the generator, its crank handle projecting through the right-hand side of the box so as to be available for use there. The generator is usually mounted on a transverse shelf across the middle of the cabinet, this shelf serving to form a compartment below it in which the dry battery of two or three cells is placed. The wall telephone-set cabinets have assumed a multitude of forms. When wet cells rather than dry cells were ordinarily employed, as was the case up to about the year 1895, the magneto generator, polarized bell, and hook switch were usually mounted in a rectangular box placed at the top of a long backboard. Immediately below this on the backboard was mounted the transmitter arm, and sometimes the base of this included the induction coil. Below this was the battery box, this being a large affair usually adapted to accommodate two and sometimes three ordinary LeClanché cells side by side. The dry cell has almost completely replaced the wet cell in this country, and as a result, the general type of wall set as shown in Figs. 142 and 143, has gradually replaced the old wet-cell type, which was more cumbrous and unsightly. It is usual on wall sets to provide some sort of a shelf, as indicated in Fig. 142, for the convenience of the user in making notes and memoranda. _Desk._ In the magneto desk-telephone sets, the so-called desk stand, containing the transmitter, the receiver, and the hook switch, with the standard upon which they are mounted, is shown in Fig. 144. This desk stand evidently does not comprise the complete equipment for a magneto desk-telephone set, since the generator, polarized bell, and battery are lacking. The generator and bell are usually mounted together in a box, either on the under side of the desk of the user or on the wall within easy reach of his chair. Connections are made between the apparatus in the desk stand proper and the battery, generator, and bell by means of flexible conducting cords, these carrying a plurality of conductors, as required by the particular circuit of the telephone in question. Such a complete magneto desk-telephone set is shown in Fig. 145, this being one of the types manufactured by the Stromberg-Carlson Manufacturing Company. [Illustration: Fig. 144. Desk Stand] A great variety of arrangements of the various parts of magneto desk-telephone apparatus is employed in practice. Sometimes, as shown in Fig. 145, the magneto bell box is equipped with binding posts for terminating all of the conductors in the cord, the line wires also running to some of these binding posts. In the magneto-telephone set illustrated the box is made large enough to accommodate only the generator and call bell, and the batteries are mounted elsewhere, as in a drawer of the desk, while in other cases there is no other equipment but that shown in the cut, the batteries being mounted within the magneto bell box itself. In still other cases, the polarized bell is contained in one box, the generator in another, the batteries in the drawer of the desk, the induction coil being mounted either in the base of the desk stand, in the bell box, or in the generator box. In such cases all of the circuits of the various scattered parts are wired to a terminal strip, located at some convenient point, this strip containing terminals for all the wires leading from the various parts and for the line wires themselves. By combining the various wires on the terminals of this terminal strip, the complete circuits of the telephone are built up. In still other cases the induction coil is mounted on the terminal strip and separate wires or sets of wires are run to the polarized bell and generator, to the desk stand itself, and to the batteries. These various arrangements are subject largely to the desire or personal ideas of the manufacturer or user. All of them work on the same principle so far as the operation of the talking and signaling circuits is concerned. [Illustration: Fig. 145. Magneto Desk Set] Circuits of Magneto-Telephone Sets. Magneto telephones, whether of the wall or desk type, may be divided into two general classes, series and bridging, according to whether the magnet of the bell is included in series or bridge relation with the telephone line when the hook is down. _Series._ In the so-called series telephone line, where several telephones are placed in series in a single line circuit, the employment of the series type of telephone results in all of the telephone bells being in series in the line circuit. This means that the voice currents originating in the telephones that are in use at a given time must pass in series through the magnets of the bells of the stations that are not in use. In order that these magnets, through which the voice currents must pass, may interfere to as small a degree as possible with the voice currents, it is common to employ low-resistance magnets in series telephones, these magnets being wound with comparatively few turns and on rather short cores so that the impedance will be as small as possible. Likewise, since the generators are required to ring all of the bells in series, they need not have a large current output, but must have sufficient voltage to ring through all of the bells in series and through the resistance of the line. For this reason the generators are usually of the three-bar type and sometimes have only two bars. In Fig. 146 are shown, in simplified form, the circuits of an ordinary series telephone. The receiver in this is shown as being removed from the hook and thus the talking apparatus is brought into play. The line wires _1_ and _2_ connect respectively to the binding posts _3_ and _4_ which form the terminals of the instrument. When the hook is up, the circuit between the binding posts _3_ and _4_ includes the receiver and the secondary winding of the induction coil, together with one of the upper contacts _5_ of the switch hook and the hook lever itself. This completes the circuit for receiving speech. The hook switch is provided with another upper contact _6_, between which and the contact _5_ is connected the local circuit containing the transmitter, the battery, and the primary of the induction coil in series. The primary and the secondary windings are connected together at one end and connected with the switch contact _5_, as shown. It is thus seen that when the hook is up the circuit through the receiver is automatically closed and also the local circuit containing the primary, the battery, and the transmitter. Thus, all the conditions for transmitting and receiving speech are fulfilled. [Fig. 146. Circuit of Series Magneto Set] When the hook is down, however, the receiving and transmitting circuits are broken, but another circuit is completed by the engagement of the hook-switch lever with the lower hook contact _7_. Between this contact and one side of the line is connected the polarized ringer and the generator. With the hook down, therefore, the circuit may be traced from the line wire _1_ to binding post _3_, thence through the generator shunt to the call bell, and thence through the lower switching contact _7_ to the binding post _4_ and line wire _2_. The generator shunt, as already described in Chapter VIII, normally keeps the generator shunted out of circuit. When, however, the generator is operated the shunt is broken, which allows the armature of the generator to come into the circuit in series with the winding of the polarized bell. The normal shunting of the generator armature from the circuit of the line is advantageous in several ways. In the first place, the impedance of the generator winding is normally cut out of the circuit so that in the case of a line with several stations the talking or voice currents do not have to flow through the generator armatures at the stations which are not in use. Again, the normal shunting of the generator tends to save the generator armature from injury by lightning. [Illustration: Fig. 147. Circuit of Series Magneto Set.] The more complete circuits of a series magneto telephone are shown in Fig. 147. In this the line binding posts are shown as _1_ and _2_. At the bottom of the telephone cabinet are four other binding posts marked _3_, _4_, _5_, and _6_. Of these _3_ and _4_ serve for the receiver terminals and _5_ and _6_ for the transmitter and battery terminals. The circuits of this diagram will be found to be essentially the same as those of Fig. 146, except that they are shown in greater detail. This particular type of circuit is one commonly employed where the generator, ringer, hook switch, and induction coil are all mounted in a so-called magneto bell box at the top of the instrument, and where the transmitter is mounted on an arm just below this box, and the battery in a separate compartment below the transmitter. The only wiring that has to be done between the bell box and the other parts of the instrument in assembling the complete telephone is to connect the receiver to the binding posts _3_ and _4_ and to connect the battery and transmitter circuit to the binding posts _5_ and _6_. _Bridging._ In other cases, where several telephones are placed on a single-line circuit, the bells are arranged in multiple across the line. For this reason their magnets are wound with a very great number of turns and consequently to a high resistance. In order to further increase the impedance, the cores are made long and heavy. Since the generators on these lines must be capable of giving out a sufficient volume of current to divide up between all of the bells in multiple, it follows that these generators must have a large current output, and at the same time a sufficient voltage to ring the bells at the farthest end of the line. Such instruments are commonly called bridging instruments, on account of the method of connecting their bells across the circuit of the line. [Illustration: Fig. 148. Circuit of Bridging Magneto Set] The fundamental characteristic of the bridging telephone is that it contains three possible bridge paths across the line wires. The first of these bridge paths is through the talking apparatus, the second through the generator, and the third through the ringer. This is shown in simplified form in Fig. 148. The talking apparatus is associated with the two upper contacts of the hook switch in the usual manner and needs no further description. The generator is the second separate bridge path, normally open, but adapted to be closed when the generator is operated, this automatic closure being performed by the movement of the crank shaft. The third bridge contains the polarized bell, and this, as a rule, is permanently closed. Sometimes, however, the arrangement is such that the bell path is normally closed through the switch which is operated by the generator crank shaft, and this path is automatically broken when the generator is operated, at which time, also, the generator path is automatically closed. This arrangement brings about the result that the generator never can ring its own bell, because its switch always operates to cut out the bell at its own station just before the generator itself is cut into the circuit. In Fig. 149 is shown the complete circuit of a bridging telephone. The circuit given in this figure is for a local-battery wall set similar in type to that shown in Figs. 142 and 143. A simplified diagrammatic arrangement is shown in the lower left-hand corner of this figure, and from a consideration of this it will be seen that the bell circuit across the line is normally completed through the two right-hand normally closed contacts of the switch on the generator. When, however, the generator is operated these two contacts are made to disengage each other while the long spring of the generator switch engages the left-hand spring and thus brings the generator itself into the circuit. [Illustration: Fig. 149. Circuit of Bridging Magneto Set] Of the three binding posts, _1_, _2_, and _3_, at the top of Fig. 149, _1_ and _2_ are for connecting with the line wires, while _8_ is for a ground connection, acting in conjunction with the lightning arrester mounted at the top of the telephone and indicated at _4_ in Fig. 149. This has no function in talking or ringing, and will be referred to more fully in Chapter XIX. Suffice it to say at this point that these arresters usually consist of two conducting bodies, one connected permanently to each of the line binding posts, and a third conducting body connected to the ground binding post. These three conducting bodies are in close proximity but carefully insulated from each other; the idea being that when the line wires are struck by lightning or subjected otherwise to a dangerous potential, the charge on the line will jump across the space between the conducting bodies and pass harmlessly to ground. NOTE. The student should practice making simplified diagrams from actual wiring diagrams. The difference between the two is that one is laid out for ease in understanding it, while the other is laid out to show the actual course of the wires as installed. If the large detailed circuit of Fig. 149 be compared with the small theoretical circuit in the same figure, the various conducting paths will be found to be the same. Such a simplified circuit does more to enable one to grasp the fundamental scheme of a complex circuit than much description, since it shows at a glance the general arrangement. The more detailed circuits are, however, necessary to show the actual paths followed by the wiring. The circuits of desk stands do not differ from those of wall sets in any material degree, except as may be necessitated by the fact that the various parts of the telephone set are not all mounted in the same cabinet or on the same standard. To provide for the necessary relative movement between the desk stand and the other portions of the set, flexible conductors are run from the desk stand itself to the stationary portions of the equipment, such as the battery and the parts contained in the generator and bell box. [Illustration: Fig. 150. Circuit of Bridging Magneto Desk Set] In Fig. 150 is shown the circuit of the Stromberg-Carlson magneto desk-telephone set, illustrated in Fig. 145. This diagram needs no explanation in view of what has already been said. The conductors, leading from the desk-stand group of apparatus to the bell-box group of apparatus, are grouped together in a flexible cord, as shown in Fig. 145, and are connected respectively to the various binding posts or contact points within the desk stand at one end and at the base of the bell box at the other end. These flexible conductors are insulated individually and covered by a common braided covering. They usually are individualized by having a colored thread woven into their insulating braid, so that it is an easy matter to identify the two ends of the same conductor at either end of the flexible cord or cable. [Illustration: Fig. 151. Common-Battery Wall Set] [Illustration: Fig. 152. Common-Battery Wall Set] Common-Battery Telephone Sets. Owing to the fact that common-battery telephones contain no sources of current, they are usually somewhat simpler than the magneto type. The component parts of a common-battery telephone, whether of the wall or desk type, are the transmitter, receiver, hook switch, polarized bell, condenser, and sometimes an induction coil. The purpose of the condenser is to prevent direct or steady currents from passing through the windings of the ringer while the ringer is connected across the circuit of the line during the time when the telephone is not in use. The requirements of common-battery signaling demand that the ringer shall be connected with the line so as to be receptive of a call at any time while the telephone is not in use. The requirements also demand that no conducting path shall normally exist between the two sides of the line. These two apparently contradictory requirements are met by placing a condenser in series with the ringer so that the ringer will be in a path that will readily transmit the alternating ringing currents sent out from the central-office generator, while at the same time the condenser will afford a complete bar to the passage of steady currents. Sometimes the condenser is also used as a portion of the talking apparatus, as will be pointed out. [Illustration: MAIN OFFICE, KANSAS CITY HOME TELEPHONE CO., KANSAS CITY, MO.] _Wall._ In Figs. 151 and 152 are given two views of a characteristic form of common-battery wall-telephone set, made by the Stromberg-Carlson Manufacturing Company. The common-battery wall set has usually taken this general form. In it the transmitter is mounted on an adjustable arm at the top of the backboard, while the box containing the bell and all working parts of the instrument is placed below the transmitter, the top of the box affording a shelf for writing purposes. In Fig. 151 are shown the hook switch and the receiver; just below these may be seen the magnets of the polarized bell, back of which is shown a rectangular box containing the condenser. Immediately in front of the ringer magnets is the induction coil. [Illustration: Fig. 153. Stromberg-Carlson Common-Battery Wall Set] In Fig. 153 are shown the details of the circuit of this instrument. This figure also includes a simplified circuit arrangement from which the principles involved may be more readily understood. It is seen that the primary of the induction coil and the transmitter are included in series across the line. The secondary of the induction coil, in series with the receiver, is connected also across the line in series with a condenser and the transmitter. _Hotel._ Sometimes, in order to economize space, the shelf of common-battery wall sets is omitted and the entire apparatus mounted in a small rectangular box, the front of which carries the transmitter mounted on the short arm or on no arm at all. Such instruments are commonly termed hotel sets, because of the fact that their use was first confined largely to the rooms in hotels. Later, however, these instruments have become very popular in general use, particularly in residences. Sometimes the boxes or cabinets of these sets are made of wood, but of recent years the tendency has been growing to make them of pressed steel. The steel box is usually finished in black enamel, baked on, the color being sometimes varied to match the color of the surrounding woodwork. In Figs. 154 and 155 are shown two views of a common-battery hotel set manufactured by the Dean Electric Company. Such sets are extremely neat in appearance and have the advantage of taking up little room on the wall and the commercial advantage of being light and compact for shipping purposes. A possible disadvantage of this type of instrument is the somewhat crowded condition which necessarily follows from the placing of all the parts in so confined a space. This interferes somewhat with the accessibility of the various parts, but great ingenuity has been manifested in making the parts readily get-at-able in case of necessity for repairs or alterations. [Illustration: Fig. 154. Steel Box Hotel] [Illustration: Fig. 155. Steel Box Hotel Set] _Desk_. The common-battery desk telephone presents a somewhat simpler problem than the magneto desk telephone for the reason that the generator and local battery, the two most bulky parts of a magneto telephone, do not have to be provided for. Some companies, in manufacturing desk stands for common-battery purposes, mount the condenser and the induction coil or impedance coil, or whatever device is used in connection with the talking circuit, in the base of the desk stand itself, and mount the polarized ringer and the condenser used for ringing purposes in a separate bell box adapted to be mounted on the wall or some portion of the desk. Other companies mount only the transmitter, receiver, and hook switch on the desk stand proper and put the condenser or induction coil, or other device associated with the talking circuit, in the bell box. There is little to choose between the two general practices. The number of conducting strands in the flexible cord is somewhat dependent on the arrangement of the circuit employed. [Illustration: Fig. 156. Common-Battery Desk Set] [Illustration: Fig. 157. Bell for Common-Battery Desk Set.] The Kellogg Switchboard and Supply Company is one which places all the parts, except the polarized ringer and the associated condenser, in the desk stand itself. In Fig. 156 is shown a bottom view of the desk stand with the bottom plate removed. In the upper portion of the circle of the base is shown a small condenser which is placed in the talking circuit in series with the receiver. In the right-hand portion of the circle of the base is shown a small impedance coil, which is placed in series with the transmitter but in shunt relation with the condenser and the receiver. [Illustration: Fig. 158. Bell for Common-Battery Desk Set] In Figs. 157 and 158 are shown two views of the type of bell box employed by the Kellogg Company in connection with the common-battery desk sets, this box being of pressed-steel construction and having a removable lid, as shown in Fig. 158, by which the working parts of the ringer are made readily accessible, as are also the terminals for the cord leading from the desk stand and for the wires of the line circuit. The condenser that is placed in series with the ringer is also mounted in this same box. By employing two condensers, one in the bell box large enough to transmit ringing currents and the other in the base of the desk stand large enough only to transmit voice currents, a duplication of condensers is involved, but it has the corresponding advantages of requiring only two strands to the flexible cord leading from the bell box to the desk stand proper. [Illustration: Fig. 159. Microtelephone Set] A form of desk-telephone set that is used largely abroad, but that has found very little use in this country, is shown in Fig. 159. In this the transmitter and the receiver are permanently attached together, the receiver being of the watch-case variety and so positioned relatively to the transmitter that when the receiver is held at the ear, the mouthpiece of the transmitter will be just in front of the lips of the user. In order to maintain the transmitter in a vertical position during use, this necessitates the use of a curved mouthpiece as shown. This transmitter and receiver so combined is commonly called, in this country, the _microtelephone set_, although there seems to be no logical reason for this name. The combined transmitter and receiver, instead of being supported on an ordinary form of hook switch, are supported on a forked bracket as shown, this bracket serving to operate the switch springs which are held in one position when the bracket is subjected to the weight of the microtelephone, and in the alternate position when relieved therefrom. This particular microtelephone set is the product of the L.M. Ericsson Telephone Manufacturing Company, of Buffalo, New York. The circuits of such sets do not differ materially from those of the ordinary desk telephone set. [Illustration: Fig. 160. Kellogg Common-Battery Desk Set] [Illustration: Fig. 161. Dean Common-Battery Set] Circuits of Common-Battery Telephone Sets. The complete circuits of the Kellogg desk-stand arrangement are shown in Fig. 160, the desk-stand parts being shown at the left and the bell-box parts at the right. As is seen, but two conductors extend from the former to the latter. A simplified theoretical sketch is also shown in the upper right-hand corner of this figure. The details of the common-battery telephone circuits of the Dean Electric Company are shown in Fig. 161. This involves the use of the balanced Wheatstone bridge. The only other thing about this circuit that needs description, in view of what has previously been said about it, is that the polarized bell is placed in series with a condenser so that the two sides of the circuit may be insulated from each other while the telephone is not in use, and yet permit the passage of ringing current through the bell. [Illustration: Fig. 162. Monarch Common-Battery Wall Set] The use of the so-called direct-current receiver has brought about a great simplification in the common-battery telephone circuits of several of the manufacturing companies. By this use the transmitter and the receiver are placed in series across the line, this path being normally opened by the hook-switch contacts. The polarized bell and condenser are placed in another bridge path across the line, this path not being affected by the hook-switch contacts. All that there is to such a complete common-battery telephone set, therefore, is a receiver, transmitter, hook switch, bell, condenser, and cabinet, or other support. The extreme simplicity of the circuits of such a set is illustrated in Fig. 162, which shows how the Monarch Telephone Manufacturing Company connect up the various parts of their telephone set, using the direct-current receiver already described in connection with Fig. 54. [Illustration: VENTILATING PLANT FOR LARGE TELEPHONE OFFICE BUILDING] CHAPTER XV NON-SELECTIVE PARTY-LINE SYSTEMS A party line is a line that is for the joint use of several stations. It is, therefore, a line that connects a central office with two or more subscribers' stations, or where no central office is involved, a line that connects three or more isolated stations with each other. The distinguishing feature of a party line, therefore, is that it serves more than two stations, counting the central office, if there is one, as a station. Strictly speaking, the term _party_ line should be used in contradistinction to the term _private_ line. Companies operating telephone exchanges, however, frequently lease their wires to individuals for private use, with no central-office switchboard connections, and such lines are, by common usage, referred to as "private lines." Such lines may be used to connect two or more isolated stations. A _private_ line, in the parlance of telephone exchange working, may, therefore, be a _party_ line, as inconsistent as this may seem. A telephone line that is connected with an exchange is an exchange line, and it is a party line if it has more than one station on it. It is an individual line or a single party line if it has but a single station on it. A line which has no central-office connection is called an "isolated line," and it is a party line if it has more than two stations on it. The problem of mere speech transmission on party lines is comparatively easy, being scarcely more complex than that involved in private or single party lines. This is not true, however, of the problem of signaling the various stations. This is because the line is for the common use of all its patrons or subscribers, as they are termed, and the necessity therefore exists that the person sending a signal, whether operator or subscriber, shall be able in some way to inform a person at the desired station that the call is intended for that station. There are two general ways of accomplishing this purpose. (_1_) The first and simplest of these ways is to make no provision for ringing any one bell on the line to the exclusion of the others, and thus allow all bells to ring at once whenever any station on the line is wanted. Where this is done, in order to prevent all stations from answering, it is necessary, in some way, to convey to the desired station the information that the call is intended for that station, and to all of the other stations the information that the call is not intended for them. This is done on such lines by what is called "code ringing," the code consisting of various combinations of long and short rings. (_2_) The other and more complex way is to arrange for selective ringing, so that the person sending the call may ring the bell at the station desired, allowing the bells at all the other stations to remain quiet. [Illustration: Fig. 163. Grounded-Circuit Series Line] These two general classes of party-line systems may, therefore, be termed "non-selective" and "selective" systems. Non-selective party lines are largely used both on lines having connection with a central office, and through the central office the privilege of connection with other lines, and on isolated lines having no central-office connection. The greatest field of usefulness of non-selective lines is in rural districts and in connection with exchanges in serving rather sparsely settled districts where the cost of individual lines or even lines serving but a few subscribers, is prohibitive. Non-selective telephone party lines most often employ magneto telephones. The early forms of party lines employed the ordinary series magneto telephone, the bells being of low resistance and comparatively low impedance, while the generators were provided with automatic shunting devices, so that their resistance would normally be removed from the circuit of the line. Series Systems. The general arrangement of a series party line employing a ground return is shown in Fig. 163. In this three ordinary series instruments are connected together in series, the end stations being grounded, in order to afford a return path for the ringing and voice currents. [Illustration: Fig. 164. Metallic-Circuit Series Line] In Fig. 164 there is shown a metallic-circuit series line on which five ordinary series telephones are placed in series. In this no ground is employed, the return being through a line wire, thus making the circuit entirely metallic. [Illustration: Fig. 165. Series Party Line] The limitations of the ordinary series party line may be best understood by reference to Fig. 165, in which the circuits of three series telephones are shown connected with a single line. The receiver of Station A is represented as being on its hook, while the receivers of Stations B and C are removed from their hooks, as when the subscribers at those two stations are carrying on a conversation. The hook switches of Stations B and C being in raised positions, the generators and ringers of those stations are cut out of the circuit, and only the telephone apparatus proper is included, but the hook switch of Station A being depressed by the weight of its receiver, includes the ringer of that station in circuit, and through this ringer, therefore, the voice currents of Stations B and C must pass. The generator of Station A is not in the circuit of voice currents, however, because of the automatic shunt with which the generator is provided, as described in Chapter VIII. A slight consideration of the series system as shown in this figure, indicates that the voice currents of any two stations that are in use, must pass (as indicated by the heavy lines) through the ringers of all the stations that are not in use; and when a great number of stations are placed upon a single line, as has been frequently the case, the impedance offered by these ringers becomes a serious barrier to the passage of the voice currents. This defect in the series party line is fundamental, as it is obvious that the ringers must be left in the circuit of the stations which are not in use, in order that those stations may always be in such condition as to be able to receive a call. This defect may in some measure be reduced by making the ringers of low impedance. This is the general practice with series telephones, the ringers ordinarily having short cores and a comparatively small number of turns, the resistance being as a rule about 80 ohms. Bridging Systems. Very much better than the series plan of party-line connections, is the arrangement by which the instruments are placed in bridges across the line, such lines being commonly known as bridged or bridging lines. This was first strongly advocated and put into wide practical use by J.J. Carty, now the Chief Engineer of the American Telephone and Telegraph Company. A simple illustration of a bridging telephone line is shown in Fig. 166, where the three telephones shown are each connected in a bridge path from the line wire to ground, a type known as a "grounded bridging line." Its use is very common in rural districts. A better arrangement is shown in Fig. 167, which represents a metallic-circuit bridging line, three telephone instruments being shown in parallel or bridge paths across the two line wires. The actual circuit arrangements of a bridging party line are better shown in Fig. 168. There are three stations and it will be seen that at each station there are three possible bridges, or bridge paths, across the two limbs of the line. The first of these bridges is controlled by the hook switch and is normally open. When the hook is raised, however, this path is closed through the receiver and secondary of the induction coil, the primary circuit being also closed so as to include the battery and transmitter. This constitutes an ordinary local-battery talking set. [Illustration: Fig. 166. Grounded Bridging Line] [Illustration: Fig. 167. Metallic Bridging Line] [Illustration: Fig. 168. Metallic Bridging Line] A second bridge at each station is led through the ringer or call-bell, and this, in most bridging telephones, is permanently closed, the continuity of this path between the two limbs of the line not being affected either by the hook switch or by the automatic switch in connection with the generator. A third bridge path at each station is led through the generator. This, as indicated, is normally open, but the automatic cut-in switch of the generator serves, when the generator is operated, to close its path across the line, so that it may send its currents to the line and ring the bells of all the stations. When any generator is operated, its current divides and passes over the line wires and through all of the ringers in multiple. It is seen, therefore, that the requirements for a bridging generator are that it shall be capable of generating a large current, sufficient when divided up amongst all the bells to ring each of them; and that it shall be capable of producing a sufficient voltage to send the required current not only to the near-by stations, but to the stations at the distant end of the line. It might seem at first that the bridging system avoided one difficulty only to encounter another. It clearly avoids the difficulty of the series system in that the voice currents, in order to reach distant stations, do not have to pass through all of the bells of the idle stations in series. There is, however, presented at each station a leakage path through the bell bridged across the line, through which it would appear the voice currents might leak uselessly from one side of the line to the other and not pass on in sufficient volume to the distant station. This difficulty is, however, more apparent than real. It is found that, by making the ringers of high impedance, the leakage of voice currents through them from one side of the line to the other is practically negligible. It is obvious that in a heavily loaded bridged line, the bell at the home station, that is at the station from which the call is being sent, will take slightly more than its share of the current, and it is also obvious that the ringing of the home bell performs no useful function. The plan is frequently adopted, therefore, of having the operation of the generator serve to cut its own bell out of the circuit. The arrangement by which this is done is clearly shown in Fig. 169. The circuit of the bell is normally complete across the line, while the circuit of the generator is normally open. When, however, the generator crank is turned these conditions are reversed, the bell circuit being broken and the generator circuit closed, so as to allow its current all to pass the line. This feature of having the local bell remain silent upon the operation of its own generator is also of advantage because other parties at the same station are not disturbed by the ringing of the bell when a call is being made by that station. A difficulty encountered on non-selective bridging party lines, which at first seems amusing rather than serious, but which nevertheless is often a vexatious trouble, is that due to the propensity of some people to "listen in" on the line on hearing calls intended for other than their own stations. People whose ethical standards would not permit them to listen at, or peep through, a keyhole, often engage in this telephonic eavesdropping. Frequently, not only one but many subscribers will respond to a call intended for others and will listen to the ensuing conversation. This is disadvantageous in several respects: It destroys the privacy of conversation between any two parties; it subjects the local batteries to an unnecessary and useless drain; and it greatly impairs the ringing efficiency of the line. The reason for this interference with ringing is that the presence of the low-resistance receivers across the line allows the current sent out by any of the generators to pass in large measure through the receivers, thus depriving the ringers, which are of comparatively high resistance and impedance, of the energy necessary to operate them. As a result of this it is frequently impossible for one party to repeat the call for another because, during the interval between the first and second call, a number of parties remove their receivers from their hooks in order to listen. Ring-off or clearing-out signals are likewise interfered with. [Illustration: Fig. 169. Circuits of Bridging Station] A partial remedy for this interference with ringing, due to eavesdropping, is to introduce a low-capacity condenser into the receiver circuit at each station, as shown in Fig. 169. This does not seriously interfere with the speech transmission since the condensers will readily transmit the high-frequency voice currents. Such condensers, however, have not sufficient capacity to enable them readily to transmit the low-frequency ringing currents and hence these are forced, in large measure, to pass through the bells for which they are intended rather than leaking through the low-resistance receiver paths. The best condenser for this use is of about 1/2-microfarad capacity, which is ample for voice-transmitting purposes, while it serves to effectively bar the major portion of the generator currents. A higher capacity condenser would carry the generator currents much more readily and thus defeat the purpose for which it was intended. In order that the requisite impedance may be given to the ringers employed for bridging party lines, it is customary to make the cores rather long and of somewhat larger diameter than in series ringers and at the same time to wind the coils with rather fine wire so as to secure the requisite number of turns. Bridging bells are ordinarily wound to a resistance of 1,000 or 1,600 ohms, these two figures having become standard practice. It is not, however, the high resistance so much as the high impedance that is striven for in bridging bells; it is the number of turns that is of principal importance. As has already been stated, the generators used for bridging lines are made capable of giving a greater current output than is necessary in series instruments, and for this purpose they are usually provided with at least four, and usually five, bar magnets. The armature is made correspondingly long and is wound, as a rule, with about No. 33 wire. Sometimes where a bridged party line terminates in a central-office switchboard it is desired to so operate the line that the subscribers shall not be able to call up each other, but shall, instead, be able to signal only the central-office operator, who, in turn, will be enabled to call the party desired, designating his station by a suitable code ring. One common way to do this is to use biased bells instead of the ordinary polarized bells. In order that the bells may not be rung by the subscribers' generators, these generators are made of the direct-current type and these are so associated with the line that the currents which they send out will be in the wrong direction to actuate the bells. On the other hand, the central-office generator is of direct-current type and is associated with the line in the right direction to energize the bells. Thus any subscriber on the line may call the central office by merely turning his generator crank, which action will not ring the bells of the subscribers on the line. The operator will then be able to receive the call and in turn send out currents of the proper direction to ring all the bells and, by code, call the desired party to the telephone. [Illustration: ONE WING OF OPERATING ROOM, BERLIN, GERMANY Ultimate Capacity 24,000 Subscribers' Lines and 2,100 Trunk Lines. Siemens-Halske Equipment. Note Horizontal Disposal of Multiple] Signal Code. The code by which stations are designated on non-selective party lines usually consists in combinations of long and short rings similar to the dots and dashes in the Morse code. Thus, one short ring may indicate Station No. 1; two short rings Station No. 2; and so on up to, say, five short rings, indicating Station No. 5. It is not good practice to employ more than five successive short rings because of the confusion which often arises in people's minds as to the number of rings that they hear. When, therefore, the number of stations to be rung by code exceeds five, it is better to employ combinations of long and short rings, and a good way is to adopt a partial decimal system, omitting the numbers higher than five in each ten, and employing long rings to indicate the tens digits and short rings to indicate the units digit, Table X. TABLE X Signal Code +--------------+---------------+--------------+---------------+ |STATION NUMBER|RING |STATION NUMBER|RING | |1 |1 short |12 |1 long, 2 short| |2 |2 short |13 |1 long, 3 short| |3 |3 short |14 |1 long, 4 short| |4 |4 short |15 |1 long, 5 short| |5 |5 short |21 |2 long, 1 short| |11 |1 long, 1 short|22 |2 long, 2 short| +--------------+---------------+--------------+---------------+ Other arrangements are often employed and by almost any of them a great variety of readily distinguishable signals may be secured. The patrons of such lines learn to distinguish, with comparatively few errors, between the calls intended for them and those intended for others, but frequently they do not observe the distinction, as has already been pointed out. Limitations. With good telephones the limit as to the number of stations that it is possible to operate upon a single line is usually due more to limitations in ringing than in talking. As the number of stations is increased indefinitely a condition will be reached at which the generators will not be able to generate sufficient current to ring all of the bells, and this condition is likely to occur before the talking efficiency is seriously impaired by the number of bridges across the line. Neither of these considerations, however, should determine the maximum number of stations to be placed on a line. The proper limit as to the number of stations is not the number that can be rung by a single generator, or the number with which it is possible to transmit speech properly, but rather the number of stations that may be employed without causing undue interference between the various parties who may desire to use the line. Overloaded party lines cause much annoyance, not only for the reason that the subscribers are often not able to use the line when they want it, but also, in non-selective lines, because of the incessant ringing of the bells, and the liability of confusion in the interpretation of the signaling code, which of course becomes more complex as the number of stations increases. The amount of business that is done over a telephone line is usually referred to as the "traffic." It will be understood, however, in considering party-line working that the number of calls per day or per hour, or per shorter unit, is not the true measure of the traffic and, therefore, not the true measure of the amount of possible interference between the various subscribers on the line. An almost equally great factor is the average length of the conversation. In city lines, that is, in lines in city exchanges, the conversation is usually short and averages perhaps two minutes in duration. In country lines, however, serving people in rural districts, who have poor facilities for seeing each other, particularly during the winter time, the conversations will average very much longer. In rural communities the people often do much of their visiting by telephone, and conversations of half an hour in length are not unusual. It is obvious that under such conditions a party line having a great many stations will be subject to very grave interference between the parties, people desiring to use the line for business purposes often being compelled to wait an undue time before they may secure the use of the line. It is obvious, therefore, that the amount of traffic on the line, whether due to many short conversations or to a comparatively few long ones, is the main factor that should determine the number of stations that, economically, may be placed on a line. The facilities also for building lines enter as a factor in this respect, since it is obvious that in comparatively poor communities the money may not be forthcoming to build as many lines as are needed to properly take care of the traffic. A compromise is, therefore, often necessary, and the only rule that may be safely laid down is to place as few parties on a given line as conditions will admit. No definite limit may be set to apply to all conditions but it may be safely stated that under ordinary circumstances no more than ten stations should be placed on a non-selective line. Twenty stations are, however, common, and sometimes forty and even fifty have been connected to a single line. In such cases the confusion which results, even if the talking and the ringing efficiency are tolerable, makes the service over such overloaded lines unsatisfactory to all concerned. CHAPTER XVI SELECTIVE PARTY-LINE SYSTEMS The problem which confronts one in the production of a system of selective ringing on party lines is that of causing the bell of any chosen one of the several parties on a circuit to respond to a signal sent out from the central office without sounding any of the other bells. This, of course, must be accomplished without interfering with the regular functions of the telephone line and apparatus. By this is meant that the subscribers must be able to call the central office and to signal for disconnection when desired, and also that the association of the selective-signaling devices with the line shall not interfere with the transmission of speech over the line. A great many ways of accomplishing selective ringing on party lines have been proposed, and a large number of them have been used. All of these ways may be classified under four different classes according to the underlying principle involved. Classification. (_1_) _Polarity_ systems are so called because they depend for their operation on the use of bells or other responsive devices so polarized that they will respond to one direction of current only. These bells or other devices are so arranged in connection with the line that the one to be rung will be traversed by current in the proper direction to actuate it, while all of the others will either not be traversed by any current at all, or by current in the wrong direction to cause their operation. (_2_) The _harmonic_ systems have for their underlying principle the fact that a pendulum or elastic reed, so supported as to be capable of vibrating freely, will have one particular rate of vibration which it may easily be made to assume. This pendulum or reed is placed under the influence of an electromagnet associated with the line, and owing to the fact that it will vibrate easily at one particular rate of vibration and with extreme difficulty at any other rate, it is clear that for current impulses of a frequency corresponding to its natural rate the reed will take up the vibration, while for other frequencies it will fail to respond. Selection on party lines by means of this system is provided for by tuning all of the reeds on the line at different rates of vibration and is accomplished by sending out on the line ringing currents of proper frequency to ring the desired bell. The current-generating devices for ringing these bells are capable of sending out different frequencies corresponding respectively to the rates of vibration of each of the vibrating reed tongues. To select any one station, therefore, the current frequency corresponding to the rate of vibration of the reed tongue at that station is sent and this, being out of tune with the reed tongues at all of the other stations, operates the tongue of the desired station, but fails to operate those at all of the other stations. (_3_) In the _step-by-step_ system the bells on the line are normally not in operative relation with the line and the bell of the desired party on the line is made responsive by sending over the line a certain number of impulses preliminary to ringing it. These impulses move step-by-step mechanisms at each of the stations in unison, the arrangement being such that the bells at the several stations are each made operative after the sending of a certain number of preliminary impulses, this number being different for all the stations. (_4_) The _broken-line_ systems are new in telephony and for certain fields of work look promising. In these the line circuit is normally broken up into sections, the first section terminating at the first station out from the central office, the second section at the second station, and so on. When the line is in its normal or inactive condition only the bell at the first station is so connected with the line circuit as to enable it to be rung, the line being open beyond. Sending a single preliminary impulse will, however, operate a switching device so as to disconnect the bell at the first station and to connect the line through to the second station. This may be carried out, by sending the proper number of preliminary impulses, so as to build up the line circuit to the desired station, after which the sending of the ringing current will cause the bell to ring at that station only. Polarity Method. The polarity method of selective signaling on party lines is probably the most extensively used. The standard selective system of the American Telephone and Telegraph Company operates on this principle. _Two-Party Line._ It is obvious that selection may be had between two parties on a single metallic-circuit line without the use of biased bells or current of different polarities. Thus, one limb of a metallic circuit may be used as one grounded line to ring the bell at one of the stations, and the other limb of the metallic circuit may be used as another grounded line to ring the bell of the other station; and the two limbs may be used together as a metallic circuit for talking purposes as usual. This is shown in Fig. 170, where the ringing keys at the central office are diagrammatically shown in the left-hand portion of the figure as _K_^{1} and _K_^{2}. The operation of these keys will be more fully pointed out in a subsequent chapter, but a correct understanding will be had if it be remembered that the circuits are normally maintained by these keys in the position shown. When, however, either one of the keys is operated, the two long springs may be considered as pressed apart so as to disengage the normal contacts between the springs and to engage the two outer contacts, with which they are shown in the cut to be disengaged. The two outer contacts are connected respectively to an ordinary alternating-current ringing generator and to ground, but the connection is reversed on the two keys. [Illustration: Fig. 170. Simple Two-Party Line Selection] At Station A the ordinary talking set is shown in simplified form, consisting merely of a receiver, transmitter, and hook switch in a single bridge circuit across the line. An ordinary polarized bell is shown connected in series with a condenser between the lower limb of the line and ground. At Station B the same talking circuit is shown, but the polarized bell and condenser are bridged between the upper limb of the line and ground. If the operator desires to call Station A, she will press key _K_^{1} which will ground the upper side of the line and connect the lower side of the line with the generator _G_^{1}, and this, obviously, will cause the bell at Station A to ring. The bell at Station B will not ring because it is not in the circuit. If, on the other hand, the operator desires to ring the bell at Station B, she will depress key _K_^{2}, which will allow the current from generator _G_^{2} to pass over the upper side of the line through the bell and condenser at Station B and return by the path through the ground. The object of grounding the opposite sides of the keys at the central office is to prevent cross-ringing, that is, ringing the wrong bell. Were the keys not grounded this might occur when a ringing current was being sent out while the receiver at one of the stations was off its hook; the ringing current from, say, generator _G_^{1} then passing not only through the bell at Station A as intended, but also through the bell at Station B by way of the bridge path through the receiver that happened to be connected across the line. With the ringing keys grounded as shown, it is obvious that this will not occur, since the path for the ringing current through the wrong bell will always be shunted by a direct path to ground on the same side of the line. In such a two-party-line selective system the two generators _G_^{1} and _G_^{2} may be the same generator and may be of the ordinary alternating-current type. The bells likewise may be of the ordinary alternating-current type. The two-party selective line just described virtually employs two separate circuits for ringing. Now each of these circuits alone may be employed to accomplish selective ringing between two stations by using two biased bells oppositely polarized, and employing pulsating ringing currents of one direction or the other according to which bell it is desired to ring. One side of a circuit so equipped is shown in Fig. 171. In this the two biased bells are at Station A and Station B, these being bridged to ground in each case and adapted to respond only to positive and negative impulses respectively. At the central office the two keys _K_^{1} and _K_^{2} are shown. A single alternating-current generator _G_ is shown, having its brush _1_ grounded and brush _2_ connected to a commutator disk _3_ mounted on the generator shaft so as to revolve therewith. One-half of the periphery of this disk is of insulating material so that the brushes _4_ and _5_, which bear against the disk, will be alternately connected with the disk and, therefore, with the brush _2_ of the generator. Now the brush _2_, being one terminal of an alternating-current machine, is alternately positive and negative, and the arrangement of the commutator is such that the disk, which is always at the potential of the brush _2_, will be connected to the brush _5_ only while it is positively charged and with the brush _4_ only while it is negatively charged. As a result, brush _5_ has a succession of positive impulses and brush _4_ a succession of negative ones. Obviously, therefore, when key _K_^{1} is depressed only the bell at Station A will be rung, and likewise the depression of key _K_^{2} will result only in the ringing of the bell at Station B. [Illustration: Fig. 171. Principle of Selection by Polarity] _Four-Party Line._ From the two foregoing two-party line systems it is evident that a four-party line system may be readily obtained, that is, by employing two oppositely polarized biased bells on each side of the metallic circuit. The selection of any of the four bells may be obtained, choosing between the pairs connected, respectively, with the two limbs of the line, by choosing the limb on which the current is to be sent, and choosing between the two bells of the pair on that side of the line by choosing which polarity of current to send. Such a four-party line system is shown in Fig. 172. In this the generators are not shown, but the wires leading from the four keys are shown marked plus or minus, according to the terminal of the generator to which they are supposed to be connected. Likewise the two bells connected with the lower side of the line are marked positive and negative, as are the two bells connected with the upper side of the line. From the foregoing description of Figs. 170 and 171, it is clear that if key _K_^{1} is pressed the bell at Station A will be rung, and that bell only, since the bells at Station C and Station _D_ are not in the circuit and the positive current sent over the lower side of the line is not of the proper polarity to ring the bell at Station B. The system shown in Fig. 172 is subject to one rather grave defect. In subsequent chapters it will be pointed out that in common-battery systems the display of the line signal at the central office is affected by any one of the subscribers merely taking his receiver off its hook and thus establishing a connection between the two limbs of the metallic circuit. Such common-battery systems should have the two limbs of the line, normally, entirely insulated from each other. It is seen that this is not the case in the system just described, since there is a conducting path from one limb of the line through the two bells on that side to ground, and thence through the other pair of bells to the other limb of the line. This means that unless the resistance of the bell windings is made very high, the path of the signaling circuit will be of sufficiently low resistance to actuate the line signal at the central office. [Illustration: Fig. 172. Four-Party Polarity Selection] It is not feasible to overcome this objection by the use of condensers in series with the bells, as was done in the system shown in Fig. 170, since the bells are necessarily biased and such bells, as may readily be seen, will not work properly through condensers, since the placing of a condenser in their circuit means that the current which passes through the bell is alternating rather than pulsating, although the original source may have been of pulsating nature only. [Illustration: Fig 173. Standard Polarity System] The remedy for this difficulty, therefore, has been to place in series with each bell a very high non-inductive resistance of about 15,000 or 20,000 ohms, and also to make the windings of the bells of comparatively high resistance, usually about 2,500 ohms. Even with this precaution there is a considerable leakage of the central-office battery current from one side of the line to the other through the two paths to ground in series. This method of selective signaling has, therefore, been more frequently used with magneto systems. An endeavor to apply this principle to common-battery systems without the objections noted above has led to the adoption of a modification, wherein a relay at each station normally holds the ground connection open. This is shown in Fig. 173 and is the standard four-party line ringing circuit employed by the American Telephone and Telegraph Company and their licensees. In this system the biased bells are normally disconnected from the line, and, therefore, the leakage path through them from one side of the line to the other does not exist. At each station there is a relay winding adapted to be operated by the ringing current bridged across the line in series with a condenser. As a result, when ringing current is sent out on the line all of the relays, _i.e._, one at each station, are energized and attract their armatures. This establishes the connection of all the bells to line and really brings about temporarily a condition equivalent to that of Fig. 172. As a result, the sending of a positive current on the lower line with a ground return will cause the operation of the bell at Station A. It will not ring the bell at Station B because of the wrong polarity. It will not ring the bells of Station C and Station D because they are in the circuit between the other side of the line and ground. As soon as the ringing current ceases all of the relays release their armatures and disconnect all the bells from the line. By this very simple device the trouble, due to marginal working of the line signal, is done away with, since normally there is no leakage from one side of the line to the other on account of the presence of the condensers in the bridge at each station. [Illustration: Fig. 174. Ringing-Key Arrangement] In Fig. 174, the more complete connections of the central-office ringing keys are shown, by means of which the proper positive or negative ringing currents are sent to line in the proper way to cause the ringing of any one of the four bells on a party line of either of the types shown in Figs. 172 and 173. In this the generator _G_ and its commutator disk _3_, with the various brushes, _1_, _2_, _4_, and _5_, are arranged in the same manner as is shown in Fig. 171. It is evident from what has been said that wire _6_ leading from generator brush _2_ and commutator disk _3_ will carry alternating potential; that wire _7_ will carry positive pulsations of potential; and that wire _8_ will carry negative pulsations of potential. There are five keys in the set illustrated in Fig. 174, of which four, viz, _K_^{1}, _K_^{2}, _K_^{3}, and _K_^{4}, are connected in the same manner as diagrammatically indicated in Figs. 172 and 173, and will, obviously, serve to send the proper current over the proper limb of the line to ring one of the bells. Key _K_^{5}, the fifth one in the set, is added so as to enable the operator to ring an ordinary unbiased bell on a single party line when connection is made with such line. As the two outside contacts of this key are connected respectively to the two brushes of the alternating-current dynamo _G_, it is clear that it will impress an alternating current on the line when its contacts are closed. _Circuits of Two-Party Line Telephones._ In Fig. 175 is shown in detail the wiring of the telephone set usually employed in connection with the party-line selective-ringing system illustrated in Fig. 170. In the wiring of this set and the two following, it must be borne in mind that the portion of the circuit used during conversation might be wired in a number of ways without affecting the principle of selective ringing employed; however, the circuits shown are those most commonly employed with the respective selective ringing systems which they are intended to illustrate. In connecting the circuits of this telephone instrument to the line, the two line conductors are connected to binding posts _1_ and _2_ and a ground connection is made to binding post _3_. In practice, in order to avoid the necessity of changing the permanent wiring of the telephone set in connecting it as an A or B Station (Fig. 170), the line conductors are connected to the binding posts in reverse order at the two stations; that is, for Station A the upper conductor, Fig. 170, is connected to binding post _1_ and the lower conductor to binding post _2_, while at Station B the upper conductor is connected to binding post _2_ and the lower conductor to binding post _1_. The permanent wiring of this telephone set is the same as that frequently used for a set connected to a line having only one station, the proper ringing circuit being made by the method of connecting up the binding posts. For example, if this telephone set were to be used on a single station line, the binding posts _1_ and _2_ would be connected to the two conductors of the line as before, while binding post _3_ would be connected to post _1_ instead of being grounded. [Illustration: Fig. 175. Circuit of Two-Party Station] _Circuits of Four-Party-Line Telephones._ The wiring of the telephone set used with the system illustrated in Fig. 172 is shown in detail in Fig. 176. The wiring of this set is arranged for local battery or magneto working, as this method of selective ringing is more frequently employed with magneto systems, on account of the objectionable features which arise when applied to common-battery systems. In this figure the line conductors are connected to binding posts _1_ and _2_, and a ground connection is made to binding post _3_. In order that all sets may be wired alike and yet permit the instrument to be connected for any one of the various stations, the bell is not permanently wired to any portion of the circuit but has flexible connections which will allow of the set being properly connected for any desired station. The terminals of the bell are connected to binding posts _9_ and _10_, to which are connected flexible conductors terminating in terminals _7_ and _8_. These terminals may be connected to the binding posts _4_, _5_, and _6_ in the proper manner to connect the set as an A, B, C, or D station, as required. For example, in connecting the set for Station A, Fig. 172, terminal _7_ is connected to binding post _6_ and _8_ to _5_. For connecting the set for Station B terminal _7_ is connected to binding post _5_ and _8_ to _6_. For connecting the set for Station C terminal _7_ is connected to binding post _6_ and _8_ to _4_. For connecting the set for Station D terminal _7_ is connected to binding post _4_ and _8_ to _6_. [Illustration: Fig. 176. Circuit of Four-Party Station without Relay] [Illustration: Fig. 177. Circuit of Four-Party Station with Relay] The detailed wiring of the telephone set employed in connection with the system illustrated in Fig. 173 is shown in Fig. 177. The wiring of this set is arranged for a common-battery system, inasmuch as this arrangement of signaling circuit is more especially adapted for common-battery working. However, this arrangement is frequently adapted to magneto systems as even with magneto systems a permanent ground connection at a subscriber's station is objectionable inasmuch as it increases the difficulty of determining the existence or location of an accidental ground on one of the line conductors. The wiring of this set is also arranged so that one standard type of wiring may be employed and yet allow any telephone set to be connected as an A, B, C, or D station. Harmonic Method. _Principles._ To best understand the principle of operation of the harmonic party-line signaling systems, it is to be remembered that a flexible reed, mounted rigidly at one end and having its other end free to vibrate, will, like a violin string, have a certain natural period of vibration; that is, if it be started in vibration, as by snapping it with the fingers, it will take up a certain rate of vibration which will continue at a uniform rate until the vibration ceases altogether. Such a reed will be most easily thrown into vibration by a series of impulses having a frequency corresponding exactly to the natural rate of vibration of the reed itself; it may be thrown into vibration by very slight impulses if they occur at exactly the proper times. It is familiar to all that a person pushing another in a swing may cause a considerable amplitude of vibration with the exertion of but a small amount of force, if he will so time his pushes as to conform exactly to the natural rate of vibration of the swing. It is of course possible, however, to make the swing take up other rates of vibrations by the application of sufficient force. As another example, consider a clock pendulum beating seconds. By gentle blows furnished by the escapement at exactly the proper times, the heavy pendulum is kept in motion. However, if a person grasps the pendulum weight and shakes it, it may be made to vibrate at almost any desired rate, dependent on the strength and agility of the individual. The conclusion is, therefore, that a reed or pendulum may be made to start and vibrate easily by the application of impulses at proper intervals, and only with great difficulty by the application of impulses at other than the proper intervals; and these facts form the basis on which harmonic-ringing systems rest. The father of harmonic ringing in telephony was Jacob B. Currier, an undertaker of Lowell, Mass. His harmonic bells were placed in series in the telephone line, and were considerably used in New England in commercial practice in the early eighties. Somewhat later James A. Lighthipe of San Francisco independently invented a harmonic-ringing system, which was put in successful commercial use at Sacramento and a few other smaller California towns. Lighthipe polarized his bells and bridged them across the line in series with condensers, as in modern practice, and save for some crudities in design, his apparatus closely resembled, both in principle and construction, some of that in successful use today. Lighthipe's system went out of use and was almost forgotten, when about 1903, Wm. W. Dean again independently redeveloped the harmonic system, and produced a bell astonishingly like that of Lighthipe, but of more refined design, thus starting the development which has resulted in the present wide use of this system. The signal-receiving device in harmonic-ringing systems takes the form of a ringer, having its armature and striker mounted on a rather stiff spring rather than on trunnions. By this means the moving parts of the bell constitute in effect a reed tongue, which has a natural rate of vibration at which it may easily be made to vibrate with sufficient amplitude to strike the gongs. The harmonic ringer differs from the ordinary polarized bell or ringer, therefore, in that its armature will vibrate most easily at one particular rate, while the armature of the ordinary ringer is almost indifferent, between rather wide limits, as to the rate at which it vibrates. As a rule harmonic party-line systems are limited to four stations on a line. The frequencies employed are usually 16-2/3, 33-1/3, 50, and 66-2/3 cycles per second, this corresponding to 1,000, 2,000, 3,000, and 4,000 cycles per minute. The reason why this particular set of frequencies was chosen is that they represent approximately the range of desirable frequencies, and that the first ringing-current machines in such systems were made by mounting the armatures of four different generators on a single shaft, these having, respectively, two poles, four poles, six poles, and eight poles each. The two-pole generator gave one cycle per revolution, the four-pole two, the six-pole three, and the eight-pole four, so that by running the shaft of the machine at exactly 1,000 revolutions per minute the frequencies before mentioned were attained. This range of frequencies having proved about right for general practice and the early ringers all having been attuned so as to operate on this basis, the practice of adhering to these numbers of vibrations has been kept up with one exception by all the manufacturers who make this type of ringer. _Tuning._ The process of adjusting the armature of a ringer to a certain rate of vibration is called tuning, and it is customary to refer to a ringer as being tuned to a certain rate of vibration, just as it is customary to refer to a violin string as being tuned to a certain pitch or rate of vibration. The physical difference between the ringers of the various frequencies consists mainly in the size of the weights at the end of the vibrating reed, that is, of the weights which form the tapper for the bell. The low-frequency ringers have the largest weights and the high-frequency the smallest, of course. The ringers are roughly tuned to the desired frequencies by merely placing on the tapper rod the desired weight and then a more refined tuning is given them by slightly altering the positions of the weights on the tapper rod. To make the reed have a slightly lower natural rate of vibration, the weight is moved further from the stationary end of the reed, while to give it a slightly higher natural rate of vibration the weight is moved toward the stationary. In this way very nice adjustments may be made, and the aim of the various factories manufacturing these bells is to make the adjustment permanent so that it will never have to be altered by the operating companies. Several years of experience with these bells has shown that when once properly assembled they maintain the same rate of vibration with great constancy. There are two general methods of operating harmonic bells. One of these may be called the in-tune system and the other the under-tune system. The under-tune system was the first employed. [Illustration: OPERATING ROOM AT TOKYO, JAPAN] _Under-Tune System._ The early workers in the field of harmonic-selective signaling discovered that when the tapper of the reed struck against gongs the natural rate of vibration of the reed was changed, or more properly, the reed was made to have a different rate of vibration from its natural rate. This was caused by the fact that the elasticity of the gongs proved another factor in the set of conditions causing the reeds to take up a certain rate of vibration, and the effect of this added factor was always to accelerate the rate of vibration which the reed had when it was not striking the gongs. The rebound of the hammer from the gongs tended, in other words, to accelerate the rate of vibration, which, as might be expected, caused a serious difficulty in the practical operation of the bells. To illustrate: If a reed were to have a natural rate of vibration, when not striking the gongs, of 50 per second and a current of 50 cycles per second were impressed on the line, the reed would take up this rate of vibration easily, but when a sufficient amplitude of vibration was attained to cause the tapper to strike the gongs, the reed would be thrown out of tune, on account of the tendency of the gongs to make the reed vibrate at a higher rate. This caused irregular ringing and was frequently sufficient to make the bells cease ringing altogether or to ring in an entirely unsatisfactory manner. In order to provide for this difficulty the early bells of Currier and Lighthipe were made on what has since been called the "under-tuned" principle. The first bells of the Kellogg Switchboard and Supply Company, developed by Dean, were based on this idea as their cardinal principle. The reeds were all given a natural rate of vibration, when not striking the gongs, somewhat below that of the current frequencies to be employed; and yet not sufficiently below the corresponding current frequency to make the bell so far out of tune that the current frequency would not be able to start it. This was done so that when the tapper began to strike the gongs the tapper would be accelerated and brought practically into tune with the current frequency, and the ringing would continue regularly as long as the current flowed. It will be seen that the under-tuned system was, therefore, one involving some difficulty in starting in order to provide for proper regularity while actually ringing. Ringers of this kind were always made with but a single gong, it being found difficult to secure uniformity of ringing and uniformity of adjustment when two gongs were employed. Although no ringers of this type are being made at present, yet a large number of them are in use and they will consequently be described. Their action is interesting in throwing better light on the more improved types, if for no other reason. Figs. 178 and 179 show, respectively, side and front views of the original Kellogg bell. The entire mechanism is self-contained, all parts being mounted on the base plate _1_. The electromagnet is of the two-coil type, and is supported on the brackets _2_ and _3_. The bracket _2_ is of iron so as to afford a magnetic yoke for the field of the electromagnet, while the bracket _3_ is of brass so as not to short-circuit the magnetic lines across the air-gap. The reed tongue--consisting of the steel spring _5_, the soft-iron armature pieces _6_, the auxiliary spring _7_, and the tapper ball _8_, all of which are riveted together, as shown in Fig. 178--constitutes the only moving part of the bell. The steel spring _5_ is rigidly mounted in the clamping piece _9_ at the upper part of the bracket _3_, and the reed tongue is permitted to vibrate only by the flexibility of this spring. The auxiliary spring _7_ is much lighter than the spring _5_ and has for its purpose the provision of a certain small amount of flexibility between the tapper ball and the more rigid portion of the armature formed by the iron strips _6-6_. The front ends of the magnet pole pieces extend through the bracket _3_ and are there provided with square soft-iron pole pieces _10_ set at right angles to the magnet cores so as to form a rather narrow air-gap in which the armature may vibrate. [Illustration: Fig. 178. Under-Tuned Ringer] The cores of the magnet and also the reed tongue are polarized by means of the =L=-shaped bar magnet _4_, mounted on the iron yoke _2_ at one end in such manner that its other end will lie quite close to the end of the spring _5_, which, being of steel, will afford a path for the lines of force to the armature proper. We see, therefore, that the two magnet cores are, by this permanent magnet, given one polarity, while the reed tongue itself is given the other polarity, this being exactly the condition that has already been described in connection with the regular polarized bell or ringer. The electromagnetic action by which this reed tongue is made to vibrate is, therefore, exactly the same as that of an ordinary polarized ringer, but the difference between the two is that, in this harmonic ringer, the reed tongue will respond only to one particular rate of vibrations, while the regular polarized ringer will respond to almost any. As shown in Fig. 178, the tapper ball strikes on the inside surface of the single gong. The function of the auxiliary spring _7_ between the ball and the main portion of the armature is to allow some resilience between the ball and the balance of the armature so as to counteract in some measure the accelerating influence of the gong on the armature. In these bells, as already stated, the natural rate of vibration of the reed tongue was made somewhat lower than the rate at which the bell was to be operated, so that the reed tongue had to be started by a current slightly out of tune with it, and then, as the tapper struck the gong, the acceleration due to the gong would bring the vibration of the reed tongue, as modified by the gong, into tune with the current that was operating it. In ether words, in this system the ringing currents that were applied to the line had frequencies corresponding to what may be called the _operative rates of vibration_ of the reed tongues, which operative rates of vibration were in each case the resultant of the natural pitch of the reed as modified by the action of the bell gong when struck. [Illustration: Fig. 179. Under-Tuned Ringer] _In-Tune System._ The more modern method of tuning is to make the natural rate of vibration of the reed tongue, that is, the rate at which it naturally vibrates when not striking the gongs, such as to accurately correspond to the rate of vibration at which the bells are to be operated--that is, the natural rate of vibration of the reed tongues is made the same as the operative rate. Thus the bells are attuned for easy starting, a great advantage over the under-tuned system. In the under-tuned system, the reeds being out of tune in starting require heavier starting current, and this is obviously conducive to cross-ringing, that is, to the response of bells to other than the intended frequency. Again, easy starting is desirable because when the armature is at rest, or in very slight vibration, it is at a maximum distance from the poles of the electromagnet, and, therefore, subject to the weakest influence of the poles. A current, therefore, which is strong enough to start the vibration, will be strong enough to keep the bell ringing properly. [Illustration: Fig. 180. Dean In-Tune Ringer] When with this "in-tune" mode of operation, the armature is thrown into sufficiently wide vibration to cause the tapper to strike the gong, the gong may tend to accelerate the vibration of the reed tongue, but the current impulses through the electromagnet coils continue at precisely the same rates as before. Under this condition of vibration, when the reed tongue has an amplitude of vibration wide enough to cause the tapper to strike the gongs, the ends of the armature come closest to the pole pieces, so that the pole pieces have their maximum magnetic effect on the armature, with the result that even if the accelerating tendency of the gongs were considerable, the comparatively large magnetic attractive impulses occurring at the same rate as the natural rate of vibration of the reed tongue, serve wholly to prevent any actual acceleration of the reed tongue. The magnetic attractions upon the ends of the armature, continuing at the initial rate, serve, therefore, as a check to offset any accelerating tendency which the striking of the gong may have upon the vibrating reed tongue. It is obvious, therefore, that in the "in-tune" system the electromagnetic effect on the armature should, when the armature is closest to the pole pieces, be of such an overpowering nature as to prevent whatever accelerating tendency the gongs may have from throwing the armature out of its "stride" in step with the current. For this reason it is usual in this type to so adjust the armature that its ends will actually strike against the pole pieces of the electromagnet when thrown into vibration. Sufficient flexibility is given to the tapper rod to allow it to continue slightly beyond the point at which it would be brought to rest by the striking of the armature ends against the pole pieces and thus exert a whipping action so as to allow the ball to continue in its movement far enough to strike against the gongs. The rebound of the gong is then taken up by the elasticity of the tapper rod, which returns to an unflexed position, and at about this time the pole piece releases the armature so that it may swing over in the other direction to cause the tapper to strike the other gong. [Illustration: Fig. 181. Tappers for Dean Ringers] The construction of the "in-tune" harmonic ringer employed by the Dean Electric Company, of Elyria, Ohio, is illustrated in Figs. 180, 181, and 182. It will be seen from Fig. 180 that the general arrangement of the magnet and armature is the same as that of the ordinary polarized ringer; the essential difference is that the armature is spring-mounted instead of pivoted. The armature and the tapper rod normally stand in the normal central position with reference to the pole pieces of the magnet and the gongs. Fig. 181 shows the complete vibrating parts of four ringers, adapted, respectively, to the four different frequencies of the system. The assembled armature, tapper rod, and tapper are all riveted together and are non-adjustable. All of the adjustment that is done upon them is done in the factory and is accomplished, first, by choosing the proper size of weight, and second, by forcing this weight into the proper position on the tapper rod to give exactly the rate of vibration that is desired. [Illustration: Fig. 182. Dean In-Tune Ringer] An interesting feature of this Dean harmonic ringer is the gong adjustment. As will be seen, the gongs are mounted on posts which are carried on levers pivoted to the ringer frame. These levers have at their outer end a curved rack provided with gear teeth adapted to engage a worm or screw thread mounted on the ringer frame. Obviously, by turning this worm screw in one direction or the other, the gongs are moved slightly toward or from the armature or tapper. This affords a very delicate means of adjusting the gongs, and at the same time one which has no tendency to work loose or to get out of adjustment. [Illustration: Fig. 183. Kellogg In-Tune Ringer] In Fig. 183 is shown a drawing of the "in-tune" harmonic ringer manufactured by the Kellogg Switchboard and Supply Company. This differs in no essential respect from that of the Dean Company, except in the gong adjustment, this latter being affected by a screw passing through a nut in the gong post, as clearly indicated. In both the Kellogg and the Dean in-tune ringers, on account of the comparative stiffness of the armature springs and on account of the normal position of the armature with maximum air gaps and consequent minimum magnetic pull, the armature will practically not be affected unless the energizing current is accurately attuned to its own natural rate. When the proper current is thrown on to the line, the ball will be thrown into violent vibration, and the ends of the armature brought into actual contact with the pole pieces, which are of bare iron and shielded in no way. The armature in this position is very strongly attracted and comes to a sudden stop on the pole pieces. The gongs are so adjusted that the tapper ball will have to spring about one thirty-second of an inch in order to hit them. The armature is held against the pole piece while the tapper ball is engaged in striking the gong and in partially returning therefrom, and so strong is the pull of the pole piece on the armature in this position that the accelerating influence of the gong has no effect in accelerating the rate of vibration of the reed. [Illustration: Fig. 184. Circuits of Dean Harmonic System] _Circuits_. In Fig. 184 are shown in simplified form the circuits of a four-station harmonic party line. It is seen that at the central office there are four ringing keys, adapted, respectively, to impress on the line ringing currents of four different frequencies. At the four stations on the line, lettered A, B, C, and D, there are four harmonic bells tuned accordingly. At Station A there is shown the talking apparatus employing the Wheatstone bridge arrangement. The talking apparatus at all of the other stations is exactly the same, but is omitted for the sake of simplicity. A condenser is placed in series with each of the bells in order that there may be no direct-current path from one side of the line to the other when all of the receivers are on their hooks at the several stations. In Fig. 185 is shown exactly the same arrangement, with the exception that the talking apparatus illustrated in detail at Station A is that of the Kellogg Switchboard and Supply Company. Otherwise the circuits of the Dean and the Kellogg Company, and in fact of all the other companies manufacturing harmonic ringing systems, are the same. _Advantages_. A great advantage of the harmonic party-line system is the simplicity of the apparatus at the subscriber's station. The harmonic bell is scarcely more complex than the ordinary polarized ringer, and the only difference between the harmonic-ringing telephone and the ordinary telephone is in the ringer itself. The absence of all relays and other mechanism and also the absence of the necessity for ground connections at the telephone are all points in favor of the harmonic system. [Illustration: Fig. 185. Circuits of Kellogg Harmonic System] _Limitations_. As already stated, the harmonic systems of the various companies, with one exception, are limited to four frequencies. The exception is in the case of the North Electric Company, which sometimes employs four and sometimes five frequencies and thus gets a selection between five stations. In the four-party North system, the frequencies, unlike those in the Dean and Kellogg systems, wherein the higher frequencies are multiples of the lower, are arranged so as to be proportional to the whole numbers 5, 7, 9, and 11, which, of course, have no common denominator. The frequencies thus employed in the North system are, in cycles per second, 30.3, 42.4, 54.5, and 66.7. In the five-party system, the frequency of 16.7 is arbitrarily added. While all of the commercial harmonic systems on the market are limited to four or five frequencies, it does not follow that a greater number than four or five stations may not be selectively rung. Double these numbers may be placed on a party line and selectively actuated, if the first set of four or five is bridged across the line and the second set of four or five is connected between one limb of the line and ground. The first set of these is selectively rung, as already described, by sending the ringing currents over the metallic circuit, while the second set may be likewise selectively rung by sending the ringing currents over one limb of the line with a ground return. This method is frequently employed with success on country lines, where it is desired to place a greater number of instruments on a line than four or five. Step-by-Step Method. A very large number of step-by-step systems have been proposed and reduced to practice, but as yet they have not met with great success in commercial telephone work, and are nowhere near as commonly used as are the polarity and harmonic systems. _Principles_. An idea of the general features of the step-by-step systems may be had by conceiving at each station on the line a ratchet wheel, having a pawl adapted to drive it one step at a time, this pawl being associated with the armature of an electromagnet which receives current impulses from the line circuit. There is thus one of these driving magnets at each station, each bridged across the line so that when a single impulse of current is sent out from the central office all of the ratchet wheels will be moved one step. Another impulse will move all of the ratchet wheels another step, and so on throughout any desired number of impulses. The ratchet wheels, therefore, are all stepped in unison. Let us further conceive that all of these ratchet wheels are provided with a notch or a hole or a projection, alike in all respects at all stations save in the position which this notch or hole or projection occupies on the wheel. The thing to get clear in this part of the conception is that all of these notches, holes, or projections are alike on all of the wheels, but they occupy a different position on the wheel for each one of the stations. Consider further that the bell circuit at each of the stations is normally open, but that in each case it is adapted to be closed when the notch, hole, or projection is brought to a certain point by the revolution of the wheel. Let us conceive further that this distinguishing notch, hole, or projection is so arranged on the wheel of the first station as to close the bell circuit when one impulse has been sent, that that on the second station will close the bell circuit after the second impulse has been sent, and so on throughout the entire number of stations. It will, therefore, be apparent that the bell circuits at the various stations will, as the wheels are rotated in unison, be closed one after the other. In order to call a given station, therefore, it is only necessary to rotate all of the wheels in unison, by sending out the proper stepping impulses until they all occupy such a position that the one at the desired station is in such position as to close the bell circuit at that station. Since all of the notches, holes, or projections are arranged to close the bell circuits at their respective stations at different times, it follows that when the bell circuit at the desired station is closed those at all of the other stations will be open. If, therefore, after the proper number of stepping impulses has been sent to the line to close the bell circuit of the desired station, ringing current be applied to the line, it is obvious that the bell of that one station will be rung to the exclusion of all others. It is, of course, necessary that provision be made whereby the magnets which furnish the energy for stepping the wheels will not be energized by the ringing current. This is accomplished in one of several ways, the most common of which is to have the stepping magnets polarized or biased in one direction and the bells at the various stations oppositely biased, so that the ringing current will not affect the stepping magnet and the stepping current will not affect the ringer magnets. After a conversation is finished, the line may be restored to its normal position in one of several ways. Usually so-called release magnets are employed, for operating on the releasing device at each station. These, when energized, will withdraw the holding pawls from the ratchets and allow them all to return to their normal positions. Sometimes these release magnets are operated by a long impulse of current, being made too sluggish in their action to respond to the quick-stepping impulses; sometimes the release magnets are tapped from one limb of the line to ground, so as not to be affected by the stepping or ringing currents sent over the metallic circuit; and sometimes other expedients are used for obtaining the release of the ratchets at the proper time, a large amount of ingenuity having been spent to this end. As practically all step-by-step party-line systems in commercial use have also certain other features intended to assure privacy of conversation to the users, and, therefore, come under the general heading of lock-out party-line systems, the discussion of commercial examples of these systems will be left for the next chapter, which is devoted to such lock-out systems. Broken-Line Method. The broken-line system, like the step-by-step system, is also essentially a lock-out system and for that reason only its general features, by which the selective ringing is accomplished, will be dealt with here. _Principles_. In this system there are no tuned bells, no positively and negatively polarized bells bridged to ground on each side of the line, and no step-by-step devices in the ordinary sense, by which selective signaling has ordinarily been accomplished on party lines. Instead of this, each instrument on the line is exclusively brought into operative relation with the line, and then removed from such operative relation until the subscriber wanted is connected, at which time all of the other instruments are locked out and the line is not encumbered by any bridge circuits at any of the instruments that are not engaged in the conversation. Furthermore, in the selecting of a subscriber or the ringing of his bell there is no splitting up of current among the magnets at the various stations as in ordinary practice, but the operating current goes straight to the station desired and to that station alone where its entire strength is available for performing its proper work. In order to make the system clear it may be stated at the outset that one side of the metallic circuit line is continued as in ordinary practice, passing through all of the stations as a continuous conductor. The other side of the line, however, is divided into sections, its continuity being broken at each of the subscriber's stations. Fig. 186 is intended to show in the simplest possible way how the circuit of the line may be extended from station to station in such manner that only the ringer of one station is in circuit at a time. The two sides of the line are shown in this figure, and it will be seen that limb _L_ extends from the central office on the left to the last station on the right without a break. The limb _R_, however, extends to the first station, at which point it is cut off from the extension _R_{x}_ by the open contacts of a switch. For the purpose of simplicity this switch is shown as an ordinary hand switch, but as a matter of fact it is a part of a relay, the operating coil of which is shown at _6_, just above it, in series with the ringer. [Illustration: Fig. 186. Principle of Broken-Line System] Obviously, if a proper ringing current is sent over the metallic circuit from the central office, only the bell at Station A will operate, since the bells at the other stations are not in the circuit. If by any means the switch lever _2_ at Station A were moved out of engagement with contact _1_ and into engagement with contact _3_, it is obvious that the bell of Station A would no longer be in circuit, but the limb _R_ of the line would be continued to the extension _R_{x}_ and the bell of Station B would be in circuit. Any current then sent over the circuit of the line from the central office would ring the bell of this station. In Fig. 187 the switches of both Station A and Station B have been thus operated, and Station C is thus placed in circuit. Inspection of this figure will show that the bells of Station A, Station B, and Station D are all cut out of circuit, and that, therefore, no current from the central office can affect them. This general scheme of selection is a new-comer in the field, and for certain classes of work it is of undoubted promise. [Illustration: Fig. 187. Principle of Broken-Line System] CHAPTER XVII LOCK-OUT PARTY-LINE SYSTEMS The party-line problem in rural districts is somewhat different from that within urban limits. In the latter cases, owing to the closer grouping of the subscribers, it is not now generally considered desirable, even from the standpoint of economy, to place more than four subscribers on a single line. For such a line selective ringing is simple, both from the standpoint of apparatus and operation; and moreover owing to the small number of stations on a line, and the small amount of traffic to and from such subscribers as usually take party-line service, the interference between parties on the same line is not a very serious matter. For rural districts, particularly those tributary to small towns, these conditions do not exist. Owing to the remoteness of the stations from each other it is not feasible from the standpoint of line cost to limit the number of stations to four. A much greater number of stations is employed and the confusion resulting is distressing not only to the subscribers themselves but also to the management of the company. There exists then the need of a party-line system which will give the limited user in rural districts a service, at least approaching that which he would get if served by an individual line. The principal investment necessary to provide facilities for telephone service is that required to produce the telephone line. In many cases the cost of instruments and apparatus is small in comparison with the cost of the line. By far the greater number of subscribers in rural districts are those who use their instruments a comparatively small number of times a day, and to maintain an expensive telephone line for the exclusive use of one such subscriber who will use it but a few minutes each day is on its face an economic waste. As a result, where individual line service is practiced exclusively one of two things must be true: either the average subscriber pays more for his service than he should, or else the operating company sells the service for less than it costs, or at best for an insufficient profit. Both of these conditions are unnatural and cannot be permanent. The party-line method of giving service, by which a single line is made to serve a number of subscribers, offers a solution to this difficulty, but the ordinary non-selective or even selective party line has many undesirable features if the attempt is made to place on it such a large number of stations as is considered economically necessary in rural work. These undesirable features work to the detriment of both the user of the telephone and the operating company. Many attempts have been made to overcome these disadvantages of the party line in sparsely settled communities, by producing what are commonly called lock-out systems. These, as their name implies, employ such an arrangement of parts that when the line is in use by any two parties, all other parties are locked out from the circuit and cannot gain access to it until the parties who are using it are through. System after system for accomplishing this purpose has been announced but for the most part these have involved such a degree of complexity and have introduced so many undesirable features as to seriously affect the smooth operation of the system and the reliability of the service. We believe, however, in spite of numerous failures, that the lock-out selective-signaling party line has a real field of usefulness and that operating companies as well as manufacturing companies are beginning to appreciate this need, and as a result that the relief of the rural subscriber from the almost intolerable service he has often had to endure is at hand. A few of the most promising lock-out party-line systems now before the public will, therefore, be described in some detail. Poole System. The Poole system is a lock-out system pure and simple, its devices being in the nature of a lock-out attachment for selective-signaling lines, either of the polarity or of the harmonic type wherein common-battery transmission is employed. It will be here described as employed in connection with an ordinary harmonic-ringing system. In Fig. 188 there is shown a four-station party line equipped with Poole lock-out devices, it being assumed that the ringers at each station are harmonic and that the keys at the central office are the ordinary keys adapted to impress the proper frequency on the line for ringing any one of the stations. In addition to the ordinary talking and ringing apparatus at each subscriber's station, there is a relay of special form and also a push-button key. [Illustration: Fig. 188. Poole Lock-Out System] Each of the relays has two windings, one of high resistance and the other of low resistance. Remembering that the system to which this device is applied is always a common-battery system, and that, therefore, the normal condition of the line will be one in which there is a difference of potential between the two limbs, it will be evident that whenever any subscriber on a line that is not in use raises his receiver from its hook, a circuit will be established from the upper contact of the hook through the lever of the hook to the high-resistance winding _1_ of the relay and thence to the other side of the line by way of wire _6_. This will result in current passing through the high-resistance winding of the relay and the relay will pull up its armature. As soon as it does so it establishes two other circuits by the closure of the relay armature against the contacts _4_ and _5_. The closing of the contact _4_ establishes a circuit from the upper side of the line through the upper contact of the switch hook, thence through the contacts of the push button _3_, thence through the low-resistance winding _2_ of the relay to the terminal _4_, thence through the relay armature and the transmitter to the lower side of the line. This low-resistance path across the line serves to hold the relay armature attracted and also to furnish current to the transmitter for talking. The establishment of this low-resistance path across the line does another important thing, however; it practically short-circuits the line with respect to all the high-resistance relay windings, and thus prevents any of the other high-resistance relay windings from receiving enough current to actuate them, should the subscriber at any other station remove his receiver from the hook in an attempt to listen in or to make a call while the line is in use. As a subscriber can only establish the proper conditions for talking and listening by the attraction of this relay armature at his station, it is obvious that unless he can cause the pulling up of his relay armature he can not place himself in communication with the line. The second thing that is accomplished by the pulling up of the relay armature is the closure of the contacts _5_, and that completes the talking circuit through the condenser and receiver across the line in an obvious fashion. The result of this arrangement is that it is the first party who raises his receiver from its hook who is enabled to successfully establish a connection with the line, all subsequent efforts, by other subscribers, failing to do so because of the fact that the line is short-circuited by the path through the low-resistance winding and the transmitter of the station that is already connected with the line. A little target is moved by the action of the relay so that a visual indication is given to the subscriber in making a call to show whether or not he is successful in getting the use of the line. If the relay operates and he secures control of the line, the target indicates the fact by its movement, while if someone else is using the line and the relay does not operate, the target, by its failure to move, indicates that fact. When one party desires to converse with another on the same line, he depresses the button _3_ at his station until after the called party has been rung and has responded. This holds the circuit of his low-resistance winding open, and thus prevents the lock-out from becoming effective until the called party is connected with the line. The relay armature of the calling party does not fall back with the establishment of the low-resistance path at the called station, because, even though shunted, it still receives sufficient current to hold its armature in its attracted position. After the called party has responded, the button at the calling station is released and both low-resistance holding coils act in multiple. [Illustration: ONE WING OF OPERATING ROOM, BERLIN, GERMANY Ultimate Capacity 24,000 Subscribers' Lines and 2,100 Trunk Lines. Siemens-Halske Equipment. Note Horizontal Disposal of Multiple Jack Field.] No induction coil is used in this system and the impedance of the holding coil is such that incoming voice currents flow through the condenser and the receiver, which, by reference to the figure, will be seen to be in shunt with the holding coil. The holding coil is in series with the local transmitter, thus making a circuit similar to that of the Kellogg common-battery talking circuit already discussed. A possible defect in the use of this system is one that has been common to a great many other lock-out systems, depending for their operation on the same general plan of action. This appears when the instruments are used on a comparatively long line. Since the locking-out of all the instruments that are not in use by the one that is in use depends on the low-resistance shunt that is placed across the line by the instrument that is in use, it is obvious that, in the case of a long line, the resistance of the line wire will enter into the problem in such a way as to tend to defeat the locking-out function in some cases. Thus, where the first instrument to use the line is at the remote end of the line, the shunting effect that this instrument can exert with respect to another instrument near the central office is that due to the resistance of the line plus the resistance of the holding coil at the end instrument. The resistance of the line wire may be so high as to still allow a sufficient current to flow through the high-resistance coil at the nearer station to allow its operation, even though the more remote instrument is already in use. Coming now to a consideration of the complete selective-signaling lock-out systems, wherein the selection of the party and the locking out of the others are both inherent features, a single example of the step-by-step, and of the broken-line selective lock-out systems will be discussed. Step-by-Step System. The so-called K.B. system, manufactured by the Dayton Telephone Lock-out Manufacturing Company of Dayton, Ohio, operates on the step-by-step principle. The essential feature of the subscriber's telephone equipment in this system is the step-by-step actuating mechanism which performs also the functions of a relay. This device consists of an electromagnet having two cores, with a permanent polarizing magnet therebetween, the arrangement in this respect being the same as in an ordinary polarized bell. The armature of this magnet works a rocker arm, which, besides stepping the selector segment around, also, under certain conditions, closes the bell circuit and the talking circuit, as will be described. [Illustration: Fig. 189. K.B. Lock-Out System] Referring first to Fig. 189, which shows in simplified form a four-station K.B. lock-out line, the electromagnet is shown at _1_ and the rocker arm at _2_. The ratchet _3_ in this case is not a complete wheel but rather a segment thereof, and it is provided with a series of notches of different depths. It is obvious that the depth of the notches will determine the degree of movement which the upper end of the rocker arm may have toward the left, this being dependent on the extent to which the pawl _6_ is permitted to enter into the segment. The first or normal notch, _i.e._, the top notch, is always of such a depth that it will allow the rocker-arm lever _2_ to engage the contact lever _4_, but will not permit the rocker arm to swing far enough to the left to cause that contact to engage the bell contact _5_. As will be shown later, the condition for the talking circuit to be closed is that the rocker arm _2_ shall rest against the contact _4_; and from this we see that the normal notch of each of the segments _3_ is of such a depth as to allow the talking circuit at each station to be closed. The next notch, _i.e._, the second one in each disk, is always shallow, as are all of the other notches except one. A deep notch is placed on each disk anywhere from the third to the next to the last on the segment. This deep notch is called the _selective notch_, and it is the one that allows of contact being made with the ringer circuit of that station when the pawl _6_ drops into it. The position of this notch differs on all of the segments on a line, and obviously, therefore, the ringer circuit at any station may be closed to the exclusion of all the others by stepping all of the segments in unison until the deep notch on the segment of the desired station lies opposite to the pawl _6_, which will permit the rocker arm _2_ to swing so far to the left as to close not only the circuit between _2_ and _4_, but also between _2_, _4_, and _5_. In this position the talking and the ringing circuits are both closed. The position of the deepest notch, _i.e._, the selective notch, on the circumference of the segment at any station depends upon the number of that station; thus, the segment of Station 4 will have a deep notch in the sixth position; the segment for Station 9 will have a deep notch in the eleventh position; the segment for any station will have a deep notch in the position corresponding to the number of that station plus two. From what has been said, therefore, it is evident that the first, or normal, notch on each segment is of such a depth as to allow the moving pawl _6_ to fall to such a depth in the segment as to permit the rocker arm _2_ to close the talking circuit only. All of the other notches, except one, are comparatively shallow, and while they permit the moving pawl _6_ under the influence of the rocker arm _2_ to move the segment _3_, yet they do not permit the rocker arm _2_ to move so far to the left as to close even the talking circuit. The exception is the deep notch, or selective notch, which is of such depth as to permit the pawl _6_ to fall so far into the segment as to allow the rocker arm _2_ to close both the talking and the ringing circuits. Besides the moving pawl _6_ there is a detent pawl _7_. This always holds the segment _3_ in the position to which it has been last moved by the moving pawl _6_. The actuating magnet _1_, as has been stated, is polarized and when energized by currents in one direction, the rocker arm moves the pawl _6_ so as to step the segment one notch. When this relay is energized by current in the opposite direction, the operation is such that both the moving pawl _6_ and the detent pawl _7_ will be pulled away from the segment, thus allowing the segment to return to its normal position by gravity. This is accomplished by the following mechanism: An armature stop is pivoted upon the face of the rocker arm so as to swing in a plane parallel to the pole faces of the relay, and is adapted, when the relay is actuated by selective impulses of one polarity, to be pulled towards one of the pole faces where it acts, through impact with a plate attached to the pole face of the relay, as a limiting means for the motion of the rocker arm when the rocker arm is actuated by the magnet. When, however, the relay is energized by current in the opposite direction, as on a releasing impulse, the armature stop swings upon its pivot towards the opposite pole face, in which position the lug on the end of the armature stop registers with a hole in the plate on the relay, thus allowing the full motion of the rocker arm when it is attracted by the magnet. This motion of the rocker arm withdraws the detent pawl from engagement with the segment as well as the moving pawl, and thereby permits the segment to return to its normal position. As will be seen from Fig. 189, each of the relay magnets _1_ is permanently bridged across the two limbs of the line. Each station is provided with a push button, not shown, by means of which the subscriber who makes a call may prevent the rocker arm of his instrument from being actuated while selective impulses are being sent over the line. The purpose of this is to enable one party to make a call for another on the same line, depressing his push button while the operator is selecting and ringing the called party. The segment at his own station, therefore, remains in its normal position, in which position, as we have already seen, his talking circuit is closed; all of the other segments are, however, stepped up until the ringing and talking circuits of the desired station are in proper position, at which time ringing current is sent over the line. The segments in Fig. 189, except at Station C, are shown as having been stepped up to the sixth position, which corresponds to the ringing position of the fourth station, or Station D. The condition shown in this figure corresponds to that in which the subscriber at Station C originated the call and pressed his button, thus retaining his own segment in its normal position so that the talking circuits would be established with Station D. When the line is in normal position any subscriber may call central by his magneto generator, not shown in Fig. 189, which will operate the drop at central, but will not operate any of the subscribers' bells, because all bell circuits are normally open. When a subscriber desires connection with another line, the operator sends an impulse back on the line which steps up and locks out all instruments except that of the calling subscriber. [Illustration: Fig. 190. K.B. Lock-Out Station] A complete K.B. lock-out telephone is shown in Fig. 190. This is the type of instrument that is usually furnished when new equipment is ordered. If, however, it is desired to use the K.B. system in connection with telephones of the ordinary bridging type that are already in service, the lock-out and selective mechanism, which is shown on the upper inner face of the door in Fig. 190, is furnished separately in a box that may be mounted close to the regular telephone and connected thereto by suitable wires, as shown in Fig. 191. It is seen that this instrument employs a local battery for talking and also a magneto generator for calling the central office. The central-office equipment consists of a dial connected with an impulse wheel, together with suitable keys by which the various circuits may be manipulated. This dial and its associated mechanism may be mounted in the regular switchboard cabinet, or it may be furnished in a separate box and mounted alongside of the cabinet in either of the positions shown at _1_ or _2_ of Fig. 192. In order to send the proper number of impulses to the line to call a given party, the operator places her finger in the hole in the dial that bears the number corresponding to the station wanted and rotates the dial until the finger is brought into engagement with the fixed stop shown at the bottom of the dial in Fig. 192. The dial is then allowed to return by the action of a spring to its normal position, and in doing so it operates a switch within the box to make and break the battery circuit the proper number of times. _Operation._ A complete description of the operation may now be had in connection with Fig. 193, which is similar to Fig. 189, but contains the details of the calling arrangement at the central office and also of the talking circuits at the various subscribers' stations. [Illustration: Fig. 191. K.B. Lock-Out Station] Referring to the central-office apparatus the usual ringing key is shown, the inside contacts of which lead to the listening key and to the operator's telephone set as in ordinary switchboard practice. Between the outside contact of this ringing key and the ringing generator there is interposed a pair of contact springs _8-8_ and another pair _9-9_. The contact springs _8_ are adapted to be moved backward and forward by the impulse wheel which is directly controlled by the dial under the manipulation of the operator. When these springs _8_ are in their normal position, the ringing circuit is continued through the release-key springs _9_ to the ringing generator. These springs _8_ occupy their normal position only when the dial is in its normal position, this being due to the notch _10_ in the contact wheel. At all other times, _i.e._, while the impulse wheel is out of its normal position, the springs _8-8_ are either depressed so as to engage the lower battery contacts, or else held in an intermediate position so as to engage neither the battery contacts nor the generator contacts. [Illustration: Fig. 192. Calling Apparatus K.B. System] When it is desired to call a given station, the operator pulls the subscriber's number on the dial and holds the ringing key closed, allowing the dial to return to normal. This connects the impulse battery to the subscriber's line as many times as is required to move the subscriber's sectors to the proper position, and in such direction as to cause the stepping movement of the various relays. As the impulse wheel comes to its normal position, the springs _8_, associated with it, again engage their upper contacts, by virtue of the notch _10_ in the impulse wheel, and this establishes the connection between the ringing generator and the subscriber's line, the ringing key being still held closed. The pulling of the transmitter dial and holding the ringing key closed, therefore, not only sends the stepping impulses to line, but also follows it by the ringing current. The sending of five impulses to line moves all of the sectors to the sixth notch, and this corresponds to the position necessary to make the fourth station operative. Such a condition is shown in Fig. 193, it being assumed that the subscriber at Station C originated the call and pressed his own button so as to prevent his sector from being moved out of its normal position. As a result of this, the talking circuit at Station C is left closed, and the talking and the ringing circuit of Station D, the called station, are closed, while both the talking and the ringing circuits of all the other stations are left open. Station D may, therefore, be rung and may communicate with Station C, while all of the other stations on the line are locked out, because of the fact that both their talking and ringing circuits are left open. [Illustration: Fig. 193. Circuit K.B. System] When conversation is ended, the operator is notified by the usual clearing-out signal, and she then depresses the release button, which brings the springs _9_ out of engagement with the generator contact but into engagement with the battery contact in such relation as to send a battery current on the line in the reverse direction from that sent out by the impulse wheel. This sends current through all of the relays in such direction as to withdraw both the moving and the holding pawls from the segments and thus allow all of the segments to return to their normal positions. Of course, in thus establishing the release current, it is necessary for the operator to depress the ringing key as well as the release key. A one-half microfarad condenser is placed in the receiver circuit at each station so that the line will not be tied up should some subscriber inadvertently leave his receiver off its hook. This permits the passage of voice currents, but not of the direct currents used in stepping the relays or in releasing them. The circuit of Fig. 193 is somewhat simplified from that in actual practice, and it should be remembered that the hook switch, which is not shown in this figure, controls in the usual way the continuity of the receiver and the transmitter circuits as well as of the generator circuits, the generator being attached to the line as in an ordinary telephone. Broken-Line System. The broken-line method of accomplishing selective signaling and locking-out on telephone party lines is due to Homer Roberts and his associates. [Illustration: Fig. 194. Roberts Latching Relay] To understand just how the principles illustrated in Figs. 186 and 187 are put into effect, it will be necessary to understand the latching relay shown diagrammatically in its two possible positions in Fig. 194, and in perspective in Fig. 195. Referring to Fig. 194, the left-hand cut of which shows the line relay in its normal position, it is seen that the framework of the device resembles that of an ordinary polarized ringer. Under the influence of current in one direction flowing through the left-hand coil, the armature of this device depresses the hard rubber stud _4_, and the springs _1_, _2_, and _3_ are forced downwardly until the spring _2_ has passed under the latch carried on the spring _5_. When the operating current through the coil _6_ ceases, the pressure of the armature on the spring _1_ is relieved, allowing this spring to resume its normal position and spring _3_ to engage with spring _2_. The spring _2_ cannot rise, since it is held by the latch _5_, and the condition shown in the right-hand cut of Fig. 194 exists. It will be seen that the spring _2_ has in this operation carried out just the same function as the switch lever performed as described in connection with Figs. 186 and 187. An analysis of this action will show that the normal contact between the springs _1_ and _2_, which contact controls the circuit through the relay coil and the bell, is not broken until the coil _6_ is de-energized, which means that the magnet is effective until it has accomplished its work. It is impossible, therefore, for this relay to cut itself out of circuit before it has caused the spring _2_ to engage under the latch _5_. If current of the proper direction were sent through the coil _7_ of the relay, the opposite end of the armature would be pulled down and the hard rubber stud at the left-hand end of the armature would bear against the bent portion of the spring _5_ in such manner as to cause the latch of this spring to release the spring _2_ and thus allow the relay to assume its normal, or unlatched, position. A good idea of the mechanical construction of this relay may be obtained from Fig. 195. The entire selecting function of the Roberts system is performed by this simple piece of apparatus at each station. [Illustration: Fig. 195. Roberts Latching Relay] The diagram of Fig. 196 shows, in simplified form, a four-station line, the circuits being given more in detail than in the diagrams of Chapter XVI. It will be noticed that the ringer and the relay coil _6_ at the first station are bridged across the sides of the line leading to the central office. In like manner the bell and the relay magnets are bridged across the two limbs of the line leading into each succeeding station, but this bridge at each of the stations beyond Station A is ineffective because the line extension _R__{x} is open at the next station nearest the central office. [Illustration: Fig. 196. Simplified Circuits of Roberts System] In order to ring Station A it is only necessary to send out ringing current from the central office. This current is in such direction as not to cause the operation of the relay, although it passes through the coil _6_. If, on the other hand, it is desired to ring Station B, a preliminary impulse would be sent over the metallic circuit from the central office, which impulse would be of such direction as to operate the relay at Station A, but not to operate the bell at that station. The operation of the relay at Station A causes the spring _2_ of this relay to engage the spring _3_, thus extending the line on to the second station. After the spring _2_ at Station A has been forced into contact with the spring _3_, it is caught by the latch of the spring _5_ and held mechanically. When the impulse from the central office ceases, the spring _1_ resumes its normal position, thus breaking the bridge circuit through the bell at that station. It is apparent now that the action of coil _6_ at Station A has made the relay powerless to perform any further action, and at the same time the line has been extended on to the second station. A second similar impulse from the central office will cause the relay at Station B to extend the line on to Station C, and at the same time break the circuit through the operating coil and the bell at Station B. In this way any station may be picked out by sending the proper number of impulses to operate the line relays of all the stations between the station desired and the central office, and having picked out a station it is only necessary to send out ringing current, which current is in such direction as to ring the bell but not to operate the relay magnet at that station. In Fig. 197, a four-station line, such as is shown in Fig. 196, is illustrated, but the condition shown in this is that existing when two preliminary impulses have been sent over the line, which caused the line relays at Station A and Station B to be operated. The bell at Station C is, therefore, the only one susceptible to ringing current from the central office. [Illustration: Fig. 197. Simplified Circuits of Roberts System] Since only one bell and one relay are in circuit at any one time, it is obvious that all of the current that passes over the line is effective in operating a single bell or relay only. There is no splitting up of the current among a large number of bells as in the bridging system of operating step-by-step devices, which method sometimes so greatly reduces the effective current for each bell that it is with great difficulty made to respond. All the energy available is applied directly to the piece of apparatus at the time it is being operated. This has a tendency toward greater surety of action, and the adjustment of the various pieces of apparatus may be made with less delicacy than is required where many pieces of apparatus, each having considerable work to do, must necessarily be operated in multiple. The method of unlatching the relays has been briefly referred to. After a connection has been established with a station in the manner already described, the operator may clear the line when it is proper to do so by sending impulses of such a nature as to cause the line relays of the stations beyond the one chosen to operate, thus continuing the circuit to the end of the line. The operation of the line relay at the last station brings into circuit the coil _8_, Figs. 196 and 197, of a grounding device. This is similar to the line relay, but it holds its operating spring in a normally latched position so as to maintain the two limbs of the line disconnected from the ground. The next impulse following over the metallic circuit passes through the coil _8_ and causes the operation of this grounding device which, by becoming unlatched, grounds the limb _L_ of the line through the coil _8_. This temporary ground at the end of the line makes it possible to send an unlocking or restoring current from the central office over the limb _L_, which current passes through all of the unlocking coils _7_, shown in Figs. 194, 196, and 197, thus causing the simultaneous unlocking of all of the line relays and the restoration of the line to its normal condition, as shown in Fig. 196. [Illustration: Fig. 198. Details of Latching Relay Connections] As has been stated, the windings _7_ on the line relays are the unlatching windings. In Figs. 196 and 197, for the purpose of simplicity, these windings are not shown connected, but as a matter of fact each of them is included in series in the continuous limb _L_ of the line. This would introduce a highly objectionable feature from the standpoint of talking over the line were it not for the balancing coils _7_^{1}, each wound on the same core as the corresponding winding _7_, and each included in series in the limb _R_ of the line, and in such direction as to be differential thereto with respect to currents passing in series over the two limbs of the line. The windings _7_ are the true unlocking windings, while the windings _7_^{1} have no other function than to neutralize the inductive effects of these unlocking windings necessarily placed in series in the talking circuit. All of these windings are of low ohmic resistance, a construction which, as has previously been noted, brings about the desired effect without introducing any self-induction in the line, and without producing any appreciable effect upon the transmission. A study of Fig. 198 will make clear the connections of these unlocking and balancing windings at each station. The statement of operation so far given discloses the general method of building up the line in sections in order to choose any party and of again breaking it up into sections when the conversation is finished. It has been stated that the same operation which selects the party wanted also serves to give that party the use of the line and to lock the others off. That this is true will be understood when it is stated that the ringer is of such construction that when operated to ring the subscriber wanted, it also operates to unlatch a set of springs similar to those shown in Fig. 194, this unlatching causing the proper connection of the subscriber's talking circuit across the limbs of the line, and also closing the local circuit through his transmitter. The very first motion of the bell armature performs this unlatching operation after which the bell behaves exactly as an ordinary polarized biased ringer. [Illustration: Fig. 199. Broken-Back Ringer] The construction of this ringer is interesting and is shown in its two possible positions in Fig. 199. The group of springs carried on its frame is entirely independent of the movement of the armature during the ringing operation. With reversed currents, however, the armature is moved in the opposite direction from that necessary to ring the bells, and this causes the latching of the springs into their normal position. In order that this device may perform the double function of ringer and relay the tapper rod of the bell is hinged on the armature so as to partake of the movements of the armature in one direction only. This has been called by the inventor and engineers of the Roberts system a _broken-back ringer_, a name suggestive of the movable relation between the armature and the tapper rod. The construction of the ringer is of the same nature as that of the standard polarized ringer universally employed, but a hinge action between the armature and the tapper rod, of such nature as to make the tapper partake positively of the movements of the armature in one direction, but to remain perfectly quiescent when the armature moves in the other direction, is provided. [Illustration: Fig. 200. Details of Ringer Connection] How this broken-back ringer controls the talking and the locking-out conditions may best be understood in connection with Fig. 200. The ringer springs are normally latched at all stations. Under these conditions the receiver is short-circuited by the engagement of springs _10_ and _11_, the receiver circuit is open between springs _10_ and _12_, and the local-battery circuit is open between springs _9_ and _12_. The subscribers whose ringers are latched are, therefore, locked out in more ways than one. When the bell is rung, the first stroke it makes unlatches the springs, which assume the position shown in the right-hand cut of Fig. 199, and this, it will be seen from Fig. 200, establishes proper conditions for enabling the subscriber to transmit and to receive speech. The hook switch breaks both transmitter and receiver circuits when down and in raising it establishes a momentary circuit between the ground and the limb _L_ of the line, both upper and lower hook contacts engaging the hook lever simultaneously during the rising of the hook. The mechanism at the central office by which selection of the proper station is made in a rapid manner is shown in Fig. 201. It has already been stated that the selection of the proper subscriber is brought about by the sending of a predetermined number of impulses from the central office, these impulses passing in one direction only and over the metallic circuit. After the proper party has been reached, the ringing current is put on in the reverse direction. [Illustration: Fig. 201. Central-Office Impulse Transmitter] The operator establishes the number of impulses to be sent by placing the pointer opposite the number on the dial corresponding to the station wanted. The ratchet wheel is stepped around automatically by each impulse of current from an ordinary pole changer such as is employed in ringing biased bells. When the required number of impulses has been sent, a projection, carried on a group of springs, drops into a notch on the drum of the selector shaft, which operation instantly stops the selecting current impulses and at the same time throws on the ringing current which consists of impulses in the reverse direction. So rapidly does this device operate that it will readily follow the impulses of an ordinary pole changer, even when this is adjusted to its maximum rate of vibration. [Illustration: VIEW OF A LARGE FOREIGN MULTIPLE SWITCHBOARD] _Operation._ Space will not permit a full discussion of the details of the central-office selective apparatus, but a general resumé of the operation of the system may now be given, with the aid of Fig. 202, which shows a four-station line with the circuits of three of the stations somewhat simplified. In this figure Station A, Station B, and Station D are shown in their locked-out positions, A and B having been passed by the selection and ringing of Station C, while Station D is inoperative because it was not reached in the selection and the line is still broken at Station C. Station C, therefore, has possession of the line. When the subscriber at Station C raised his receiver in order to call central, a "flash" contact was made as the hook moved up, which momentarily grounded the limb _L_ of the line. (See Fig. 200.) This "flash" contact is produced by the arrangement of the hook which assures that the lower contact shall, by virtue of its flexibility, follow up the hook lever until the hook lever engages the upper contact, after which the lower contact breaks. This results in the momentary connection of both the upper and the lower contacts of the hook with the lever, and, therefore, the momentary grounding of the limb _L_ of the line. This limb always being continuous serves, when this "flash" contact is made, to actuate the line signal at the central office. [Illustration: Fig. 202. Circuits of Roberts Line] Since, however, all parties on the line are normally locked out of talking circuits, some means must be provided whereby the operator may place the signaling party in talking connection and leave all the other instruments on the line in their normally locked-out position. In fact, the operator must be able automatically to pick out the station that signaled in, and operate the ringer to unlatch the springs controlling the talking circuit of that station. Accordingly the operator sends impulses on the line, from a grounded battery, which are in the direction to operate the line relays and to continue the line circuit to the station calling. When, after a sufficient number of impulses, this current reaches that station it finds a path to ground from the limb _L_. This path is made possible by the fact that the subscriber's receiver is off its hook at that station. In order to understand just how this ground connection is made, it must be remembered that each of the ringer magnets is energized with each selecting impulse, but in such a direction as not to ring the bells, it being understood that all of the ringer mechanisms are normally latched. When the selecting impulse for Station C arrives, it passes through the ringer and the selecting relay coils at that station and starts to operate the remainder of the ringers sufficiently to cause the spring _12_ to engage the spring _13_. This establishes the ground connection from the limb _L_ of the line, the circuit being traced through limb _L_ through the upper contact of the switch, thence through springs _12_ and _13_ to ground, and this, before the line relay has time to latch, operates the quick-acting relay at the central office, which acts to cut off further impulses, and thus automatically stops at the calling station. Ringing current in the opposite direction is then sent to line; this unlatches the ringer springs and places the calling subscriber in talking circuit. When the operator has communicated with the calling subscriber, and found, for example, that another party on another similar line is desired, she turns the dial pointer on the selector to the number corresponding to the called-for party's number on that line, and presses the signal key. Pressing this key causes impulses to "run down the line," selecting the proper party and ringing his bell in the manner already described. The connection between the two parties is then established, and no one else can in any possible way, except by permission of the operator, obtain access to the line. It is obvious that some means must be provided for restoring the selecting relays to normal after a conversation is finished. By referring to Fig. 194 it will be seen that the upper end of the latch spring _5_ is bent over in such a manner that when the armature is attracted by current flowing through the coil _7_, the knob on the left-hand end of the armature on rising engages with the bent cam surface and forces back the latch, permitting spring _2_ to return to its normal position. To restore the line the operator sends out sufficient additional selective impulses to extend the circuit to the end of the line, and thus brings the grounder into circuit. The winding of the grounder is connected in such a manner that the next passing impulse throws off its latch, permitting the long spring to contact with the ground spring. The operator now sends a grounded impulse over the continuous limb _L_ of the line which passes through the restoring coils _7_ at all the stations and through the right-hand coil of the grounding device to ground. The selecting relays are, therefore, simultaneously restored to normal. The grounder is also energized and restored to its normal position by the same current. If a party in calling finds that his own line is busy and he cannot get central, he may leave his receiver off its hook. When the party who is using the line hangs up his receiver the fact that another party desires a connection is automatically indicated to the operator, who then locks out the instrument of the party who has just finished conversation and passes his station by. When the operator again throws the key, the waiting subscriber is automatically selected in the same manner as was the first party. If there are no subscribers waiting for service, the stop relay at central will not operate until the grounder end of the line is unlatched, the selecting relays being then restored automatically to normal. The circuits are so organized that at all times whether the line is busy or not, the movement up and down of the switch hook, at any sub-station, operates a signal before the operator. Such a movement, when made slowly and repeatedly, indicates to the operator that the subscriber has an emergency call and she may use her judgment as to taking the line away from the parties who are using it, and finding out what the emergency call is for. If the operator finds that the subscriber has misused this privilege of making the emergency call, she may restore the connection to the parties previously engaged in conversation. One of the salient points of this Roberts system is that the operator always has control of the line. A subscriber is not able even to use his own battery till permitted to do so. A subscriber who leaves his receiver off its hook in order that he may be signaled by the operator when the line is free, causes no deterioration of the local battery because the battery circuit is held open by the switch contacts carried on the ringer. It cannot be denied, however, that this system is complicated, and that it has other faults. For instance, as described herein, both sides of the line must be looped into each subscriber's station, thus requiring four drop, or service, wires instead of two. It is possible to overcome this objection by placing the line relays on the pole in a suitably protected casing, in which case it is sufficient to run but two drop wires from the nearer line to station. There are undoubtedly other objections to this system, and yet with all its faults it is of great interest, and although radical in many respects, it teaches lessons of undoubted value. CHAPTER XVIII ELECTRICAL HAZARDS All telephone systems are exposed to certain electrical hazards. When these hazards become actively operative as causes, harmful results ensue. The harmful results are of two kinds: those causing damage to property and those causing damage to persons. The damage to persons may be so serious as to result in death. Damage to property may destroy the usefulness of a piece of apparatus or of some portion of the wire plant. Or the property damage may initiate itself as a harm to apparatus or wiring and may result in greater and extending damage by starting a fire. Electrical currents which endanger life and property may be furnished by natural or artificial causes. Natural electricity which does such damage usually displays itself as lightning. In rare cases, currents tending to flow over grounded lines because of extraordinary differences of potential between sections of the earth's surface have damaged apparatus in such lines, or only have been prevented from causing such damage by the operation of protective devices. Telegraph and telephone systems have been threatened by natural electrical hazards since the beginning of the arts and by artificial electrical hazards since the development of electric light and power systems. At the present time, contrary to the general supposition, it is in the artificial, and not in the natural electrical hazards that the greater variety and degree of danger lies. Of the ways in which artificial electricity may injure a telephone system, the entrance of current from an external electrical power system is a greater menace than an abnormal flow of current from a source belonging to the telephone system itself. Yet modern practice provides opportunities for a telephone system to inflict damage upon itself in that way. Telephone engineering designs need to provide means for protecting _all_ parts of a system against damage, from external ("foreign") as well as internal ("domestic") hazards, and to cause this protection to be inclusive enough to protect persons against injury and property from damage by any form of overheating or electrolytic action. A part of a telephone system for which there is even a remote possibility of contact with an external source of electrical power, whether natural or artificial, is said to be _exposed_ to electrical hazard. The degree or character of possible contact or other interference often is referred to in relative terms of _exposure_. The same terms are used concerning inductive relations between circuits. The whole tendency of design, particularly of wire plants, is to arrange the circuits in such a way as to limit the exposure as greatly as possible, the intent being to produce a condition in which all parts of the system will be _unexposed_ to hazards. Methods of design are not yet sufficiently advanced for any plant to be formed of circuits wholly unexposed, so that protective means are required to safeguard apparatus and circuits in case the hazard, however remote, becomes operative. Lightning discharges between the clouds and earth frequently charge open wires to potentials sufficiently high to damage apparatus; and less frequently, to destroy the wires of the lines themselves. Lightning discharges between clouds frequently induce charges in lines sufficient to damage apparatus connected with the lines. Heavy rushes of current in lines, from lightning causes, occasionally induce damaging currents in adjacent lines not sufficiently exposed to the original cause to have been injured without this induction. The lightning hazard is least where the most lines are exposed. In a small city with all of the lines formed of exposed wires and all of them used as grounded circuits, a single lightning discharge may damage many switchboard signals and telephone ringers if there be but 100 or 200 lines, while the damage might have been nothing had there been 800 to 1,000 lines in the same area. Means of protecting lines and apparatus against damage by lightning are little more elaborate than in the earliest days of telegraph working. They are adequate for the almost entire protection of life and of apparatus. Power circuits are classified by the rules of various governing bodies as high-potential and low-potential circuits. The classification of the National Board of Fire Underwriters in the United States defines low-potential circuits as having pressures below 550 volts; high-potential circuits as having pressures from 550 to 3,500 volts, and extra high-potential circuits as having pressures above 3,500 volts. Pressures of 100,000 volts are becoming more common. Where power is valuable and the distance over which it is to be transmitted is great, such high voltages are justified by the economics of the power problem. They are a great hazard to telephone systems, however. An unprotected telephone system meeting such a hazard by contact will endanger life and property with great certainty. A very common form of distribution for lighting and power purposes is the three-wire system having a grounded neutral wire, the maximum potential above the earth being about 115 volts. Telephone lines and apparatus are subject to damage by any power circuit whether of high or low potential. The cause of property damage in all cases is the flow of current. Personal damage, if it be death from shock, ordinarily is the result of a high potential between two parts of the body. The best knowledge indicates that death uniformly results from shock to the heart. It is believed that death has occurred from shock due to pressure as low as 100 volts. The critical minimum voltage which can not cause death is not known. A good rule is never willingly to subject another person to personal contact with any electrical pressure whatever. Electricity can produce actions of four principal kinds: physiological, thermal, chemical, and magnetic. Viewing electricity as establishing hazards, the physiological action may injure or kill living things; the thermal action may produce heat enough to melt metals, to char things which can be burned, or to cause them actually to burn, perhaps with a fire which can spread; the chemical action may destroy property values by changing the state of metals, as by dissolving them from a solid state where they are needed into a state of solution where they are not needed; the magnetic action introduces no direct hazard. The greatest hazard to which property values are exposed is the electro-thermal action; that is, the same useful properties by which electric lighting and electric heating thrive may produce heat where it is not wanted and in an amount greater than can safely be borne. The tendency of design is to make all apparatus capable of carrying without overheating any current to which voltage within the telephone system may subject it, and to provide the system so designed with specific devices adapted to isolate it from currents originating without. Apparatus which is designed in this way, adapted not only to carry its own normal working currents but to carry the current which would result if a given piece of apparatus were connected directly across the maximum pressure within the telephone system itself, is said to be self-protecting. Apparatus amply able to carry its maximum working current but likely to be overheated, to be injured, or perhaps to destroy itself and set fire to other things if subjected to the maximum pressure within the system, is not self-protecting apparatus. To make all electrical devices self-protecting by surrounding them with special arrangements for warding off abnormal currents from external sources, is not as simple as might appear. A lamp, for example, which can bear the entire pressure of a central-office battery, is not suitable for direct use in a line several miles long because it would not give a practical signal in series with that line and with the telephone set, as it is required to do. A lamp suitable for use in series with such a line and a telephone set would burn out by current from its own normal source if the line should become short-circuited in or near the central office. The ballast referred to in the chapter on "Signals" was designed for the very purpose of providing rapidly-rising resistance to offset the tendency toward rapidly-rising current which could burn out the lamp. As another example, a very small direct-current electric motor can be turned on at a snap switch and will gain speed quickly enough so that its armature winding will not be overheated. A larger motor of that kind can not be started safely without introducing resistance into the armature circuit on starting, and cutting it out gradually as the armature gains speed. Such a motor could be made self-protecting by having the armature winding of much larger wire than really is required for mere running, choosing its size great enough to carry the large starting current without overheating itself and its insulation. It is better, and for long has been standard practice, to use starting boxes, frankly admitting that such motors are not self-protecting until started, though they are self-protecting while running at normal speeds. Such a motor, once started, may be overloaded so as to be slowed down. So much more current now can pass through the armature that its winding is again in danger. Overload circuit-breakers are provided for the very purpose of taking motors out of circuit in cases where, once up to speed, they are mechanically brought down again and into danger. Such a circuit-breaker is a device for protecting against an _internal_ hazard; that is, internal to the power system of which the motor is a part. Another example: In certain situations, apparatus intended to operate under impulses of large current may be capable of carrying its normal impulses successfully but incapable of carrying currents from the same pressure continuously. Protective means may be provided for detaching such apparatus from the circuit whenever the period in which the current acts is not short enough to insure safety. This is cited as a case wherein a current, normal in amount but abnormal in duration, becomes a hazard. The last mentioned example of damage from internal hazards brings us to the law of the electrical generation of heat. _The greater the current or the greater the resistance of the conductor heated or the longer the time, the greater will he the heat generated in that conductor._ But this generated heat varies directly as the resistance and as the time and as the square of the current, that is, the law is Heat generated = _C^{2}Rt_ in which _C_ = the current; _R_=the resistance of the conductor; and _t_ = the time. It is obvious that a protective device, such as an overload circuit-breaker for a motor, or a protector for telephone apparatus, needs to operate more quickly for a large current than for a small one, and this is just what all well-designed protective devices are intended to do. The general problem which these heating hazards present with relation to telephone apparatus and circuits is: _To cause all parts of the telephone system to be made so as to carry successfully all currents which may flow in them because of any internal or external pressure, or to supplement them by devices which will stop or divert currents which could overheat them._ Electrolytic hazards depend not on the heating effects of currents but on their chemical effects. The same natural law which enables primary and secondary batteries to be useful provides a hazard which menaces telephone-cable sheaths and other conductors. When a current leaves a metal in contact with an electrolyte, the metal tends to dissolve into the electrolyte. In the processes of electroplating and electrotyping, current enters the bath at the anode, passes from the anode through the solution to the cathode, removing metal from the former and depositing it upon the latter. In a primary battery using zinc as the positive element and the negative terminal, current is caused to pass, within the cell, from the zinc to the negative element and zinc is dissolved. Following the same law, any pipe buried in the earth may serve to carry current from one region to another. As single-trolley traction systems with positive trolley wires constantly are sending large currents through the earth toward their power stations, such a pipe may be of positive potential with relation to moist earth at some point in its length. Current leaving it at such a point may cause its metal to dissolve enough to destroy the usefulness of the pipe for its intended purpose. Lead-sheathed telephone cables in the earth are particularly exposed to such damage by electrolysis. The reasons are that such cables often are long, have a good conductor as the sheath-metal, and that metal dissolves readily in the presence of most aqueous solutions when electrolytic differences of potential exist. The length of the cables enables them to connect between points of considerable difference of potential. It is lack of this length which prevents electrolytic damage to masses of structural metal in the earth. Electrical power is supplied to single-trolley railroads principally in the form of direct current. Usually all the trolley wires of a city are so connected to the generating units as to be positive to the rails. This causes current to flow from the cars toward the power stations, the return path being made up jointly of the rails, the earth itself, actual return wires which may supplement the rails, and also all other conducting things in the earth, these being principally lead-covered cables and other pipes. These conditions establish definite areas in which the currents tend to leave the cables and pipes, _i.e._, in which the latter are positive to other things. These positive areas usually are much smaller than the negative areas, that is, the regions in which currents tend _to enter_ the cables form a larger total than the regions in which the currents tend _to leave_ the cables. These facts simplify the ways in which the cables may be protected against damage by direct currents leaving them and also they reduce the amount, complication, and cost of applying the corrective and preventive measures. All electric roads do not use direct current. Certain simplifications in the use of single-phase alternating currents in traction motors have increased the number of roads using a system of alternating-current power supply. Where alternating current is used, the electrolytic conditions are different and a new problem is set, for, as the current flows in recurrently different directions, an area which at one instant is positive to others, is changed the next instant into a negative area. The protective means, therefore, must be adapted to the changed requirements. CHAPTER XIX PROTECTIVE MEANS Any of the heating hazards described in the foregoing chapter may cause currents which will damage apparatus. All devices for the protection of apparatus from such damage, operate either to stop the flow of the dangerous current, or to send that flow over some other path. Protection Against High Potentials. Lightning is the most nearly universal hazard. All open wires are exposed to it in some degree. Damaging currents from lightning are caused by extraordinarily high potentials. Furthermore, a lightning discharge is oscillatory; that is, alternating, and of very high frequency. Drops, ringers, receivers, and other devices subject to lightning damage suffer by having their windings burned by the discharge. The impedance these windings offer to the high frequency of lightning oscillations is great. The impedance of a few turns of heavy wire may be negligible to alternating currents of ordinary frequencies because the resistance of the wire is low, its inductance small, and the frequency finite. On the other hand, the impedance of such a coil to a lightning discharge is much higher, due to the very high frequency of the discharge. Were it not for the extremely high pressure of lightning discharges, their high frequency of oscillation would enable ordinary coils to be self-protecting against them. But a discharge of electricity can take place through the air or other insulating medium if its pressure be high enough. A pressure of 70,000 volts can strike across a gap in air of one inch, and lower pressures can strike across smaller distances. When lightning encounters an impedance, the discharge seldom takes place through the entire winding, as an ordinary current would flow, usually striking across whatever short paths may exist. Very often these paths are across the insulation between the outer turns of a coil. It is not unusual for a lightning discharge to plow its way across the outer layer of a wound spool, melting the copper of the turns as it goes. Often the discharge will take place from inner turns directly to the core of the magnet. This is more likely when the core is grounded. _Air-Gap Arrester_. The tendency of a winding to oppose lightning discharges and the ease with which such discharge may strike across insulating gaps, points the way to protection against them. Such devices consist of two conductors separated by an air space or other insulator and are variously known as lightning arresters, spark gaps, open-space cutouts, or air-gap arresters. The conductors between which the gap exists may be both of metal, may be one of metal and one of carbon, or both of carbon. One combination consists of carbon and mercury, a liquid metal. The space between the conductors may be filled with either air or solid matter, or it may be a vacuum. Speaking generally, the conductors are separated by some insulator. Two conductors separated by an insulator form a condenser. The insulator of an open-space arrester often is called the dielectric. [Illustration Fig. 203. Saw Tooth Arrester] Discharge Across Gaps:--Electrical discharges across a given distance occur at lower potentials if the discharge be between points than if between smooth surfaces. Arresters, therefore, are provided with points. Fig. 203 shows a device known as a "saw-tooth" arrester because of its metal plates being provided with teeth. Such an arrester brings a ground connection close to plates connected with the line and is adapted to protect apparatus either connected across a metallic circuit or in series with a single wire circuit. Fig. 201 shows another form of metal plate air-gap arrester having the further possibility of a discharge taking place from one line wire to the other. Inserting a plug in the hole between the two line plates connects the line wires directly together at the arrester. This practice was designed for use with series lines, the plug short-circuiting the telephone set when in place. A defect of most ordinary types of metal air-gap lightning arresters is that heavy discharges tend to melt the teeth or edges of the plates and often to weld them together, requiring special attention to re-establish the necessary gap. Advantages of Carbon:--Solid carbon is found to be a much better material than metal for the reasons that a discharge will not melt it and that its surface is composed of multitudes of points from which discharges take place more readily than from metals. [Illustration Fig. 204. Saw-Tooth Arrester] [Illustration Fig. 205. Carbon Block Arrester] Carbon arresters now are widely used in the general form shown in Fig. 205. A carbon block connected with a wire of the line is separated from a carbon block connected to ground by some form of insulating separator. Mica is widely used as such a separator, and holes of some form in a mica slip enable the discharge to strike freely from block to block, while preventing the blocks from touching each other. Celluloid with many holes is used as a separator between carbon blocks. Silk and various special compositions also have their uses. [Illustration Fig. 206. Arrester Separators] Dust Between Carbons:--Discharges between the carbon blocks tend to throw off particles of carbon from them. The separation between the blocks being small--from .005 to .015 inch--the carbon particles may lodge in the air-gap, on the edges of the separator, or otherwise, so as to leave a conducting path between the two blocks. Slight moisture on the separator may help to collect this dust, thus placing a ground on that wire of the line. This ground may be of very high resistance, but is probably one of many such--one at each arrester connected to the line. In special forms of carbon arresters an attempt has been made to limit this danger of grounding by the deposit of carbon dust. The object of the U-shaped separator of Fig. 206 is to enable the arrester to be mounted so that this opening in the separator is downward, in the hope that loosened carbon particles may fall out of the space between the blocks. The deposit of carbon on the inside edges of the U-shaped separator often is so fine and clings so tightly as not to fall out. The separator projects beyond the blocks so as to avoid the collection of carbon on the outer edges. Commercial Types:--Fig. 207 is a commercial form of the arrangement shown in Fig. 205 and is one of the many forms made by the American Electric Fuse Company. Line wires are attached to outside binding posts shown in the figure and the ground wire to the metal binding post at the front. The carbon blocks with their separator slide between clips and a ground plate. The air-gap is determined by the thickness of the separator between the carbon blocks. [Illustration: Fig. 207. Carbon Block Arrester] [Illustration: Fig. 208 Roberts "Self-Cleaning" Arrester] The Roberts carbon arrester is designed with particular reference to the disposal of carbon dust and is termed self-cleaning for that reason. The arrangement of carbons and dielectric in this device is shown in Fig. 208; mica is cemented to the line carbon and is large enough to provide a projecting margin all around. The spark gap is not uniform over the entire surface of the block but is made wedge-shaped by grinding away the line carbon as shown. It is claimed that a continuous arcing fills the wedge-shaped chamber with heated air or gas, converting the whole of the space into a field of low resistance to ground, and that this gas in expanding drives out every particle of carbon that may be thrown off. It seems obvious that the wedge-shaped space offers greater freedom for carbon dust to fall out than in the case of the parallel arrangement of the block faces. An outdoor arrester for metallic circuits, designed by F.B. Cook, is shown in Fig. 209. The device is adapted to mount on a pole or elsewhere and to be covered by a protecting cap. The carbons are large and are separated by a special compound intended to assist the self-cleaning feature. The three carbons being grouped together as a unit, the device has the ability to care for discharges from one terminal to either of the others direct, without having to pass through two gaps. In this particular, the arrangement is the same as that of Fig. 204. [Illustration: Fig. 209. Cook Air-Gap Arrester] A form of Western Electric arrester particularly adapted for outside use on railway lines is shown with its cover in Fig. 210. [Illustration: Fig. 210. Western Electric Air-Gap Arrester] The Kellogg Company regularly equips its magneto telephones with air-gap arresters of the type shown in Fig. 211. The two line plates are semicircular and of metal. The ground plate is of carbon, circular in form, covering both line plates with a mica separator. This is mounted on the back board of the telephone and permanently wired to the line and ground binding posts. [Illustration: OLD SWITCHBOARD OF BELL EXCHANGE SERVING CHINATOWN, SAN FRANCISCO, CALIFORNIA] [Illustration: Fig. 211. Kellogg Air-Gap Arrester] Vacuum Arresters:--All of the carbon arresters so far mentioned depend on the discharge taking place through air. A given pressure will discharge further in a fairly good vacuum than in air. The National Electric Specialty Company mounts three conductors in a vacuum of the incandescent lamp type, Fig. 212. A greater separation and less likelihood of short-circuiting can be provided in this way. Either carbon or metal plates are adapted for use in such vacuum devices. The plates may be further apart for a given discharge pressure if the surfaces are of carbon. [Illustration: Fig. 212. Vacuum Arrester] Introduction of Impedance:--It has been noted that the existence of impedance tends to choke back the passage of lightning discharge through a coil. Fig. 213 suggests the relation between such an impedance and air-gap arrester. If the coil shown therein be considered an arrangement of conductors having inductance, it will be seen that a favorable place for an air-gap arrester is between that impedance and the line. This fact is made known in practice by frequent damage to aërial cables by electricity brought into them over long open wires, the discharge taking place at the first turn or bend in the aërial cable; this discharge often damages both core and sheath. It is well to have such bends as near the end of the cable as possible, and turns or goosenecks at entrances to terminals have that advantage. [Illustration: Fig. 213. Impedance and Air-Gap] This same principle is utilized in some forms of arresters, such as the one shown in Fig. 214, which provides an impedance of its own directly in the arrester element. In this device an insulating base carries a grounded carbon rod and two impedance coils. The impedance coils are wound on insulating rods, which hold them near, but not touching, the ground carbon. The coils are arranged so that they may be turned when discharges roughen the surfaces of the wires. [Illustration: Fig. 214. Holtzer-Cabot Arrester] Metallic Electrodes:--Copper or other metal blocks with roughened surfaces separated by an insulating slip may be substituted for the carbon blocks of most of the arresters previously described. Metal blocks lack the advantage of carbon in that the latter allows discharges at lower potentials for a given separation, but they have the advantage that a conducting dust is not thrown off from them. [Illustration: Fig. 215. Carbon Air-Gap Arrester] Provision Against Continuous Arc:--For the purpose of short-circuiting an arc, a globule of low-melting alloy may be placed in one carbon block of an arrester. This feature is not essential in an arrester intended solely to divert lightning discharges. Its purpose is to provide an immediate path to ground if an arc arising from artificial electricity has been maintained between the blocks long enough to melt the globule. Fig. 215 is a plan and section of the Western Electric Company's arrester used as the high potential element in conjunction with others for abnormal currents and sneak currents; the latter are currents too small to operate air-gap arresters or substantial fuses. Protection Against Strong Currents. _Fuses._ A fuse is a metal conductor of lower carrying capacity than the circuit with which it is in series at the time it is required to operate. Fuses in use in electrical circuits generally are composed of some alloy of lead, which melts at a reasonably low temperature. Alloys of lead have lower conductivity than copper. A small copper wire, however, may fuse at the same volume of current as a larger lead alloy wire. Proper Functions:--A fuse is not a good lightning arrester. As lightning damage is caused by current and as it is current which destroys a fuse, a lightning discharge _can_ open a circuit over which it passes by melting the fuse metal. But lightning may destroy a fuse and at the same discharge destroy apparatus in series with the fuse. There are two reasons for this: One is that lightning discharges act very quickly and may have destroyed apparatus before heating the fuse enough to melt it; the other reason is that when a fuse is operated with enough current even to vaporize it, the vapor serves as a conducting path for an instant after being formed. This conducting path may be of high resistance and still allow currents to flow through it, because of the extremely high pressure of the lightning discharge. A comprehensive protective system may include fuses, but it is not to be expected that they always will arrest lightning or even assist other things in arresting lightning. They should be considered as of no value for that purpose. Furthermore, fuses are best adapted to be a part of a general protective system when they do all that they must do in stopping abnormal currents and yet withstand lightning discharges which may pass through them. Other things being equal, that system of protection is best in which all lightning discharges are arrested by gap arresters and in which no fuses ever are operated by lightning discharges. Mica Fuse:--A convenient and widely used form of fuse is that shown in Fig. 216. A mica slip has metal terminals at its ends and a fuse wire joins these terminals. The fuse is inserted in the circuit by clamping the terminals under screws or sliding them between clips as in Figs. 217 and 218. Advantages of this method of fuse mounting for protecting circuits needing small currents are that the fuse wire can be seen, the fuses are readily replaced when blown, and their mountings may be made compact. As elements of a comprehensive protective system, however, the ordinary types of mica-slip fuses are objectionable because too short, and because they have no means of their own for extinguishing an arc which may follow the blowing of the fuses. As protectors for use in distributing low potential currents from central-office power plants they are admirable. By simple means, they may be made to announce audibly or visibly that they have operated. [Illustration: Fig. 216. Mica Slip Fuse] [Illustration: Fig. 217. Postal Type Mica Fuse] [Illustration: Fig. 218. Western Union Type Mica Fuse] Enclosed Fuses:--If a fuse wire within an insulating tube be made to connect metal caps on that tube and the space around the tube be filled with a non-conducting powder, the gases of the vaporized fuse metal will be absorbed more quickly than when formed without such imbedding in a powder. The filling of such a tubular fuse also muffles the explosion which occurs when the fuse is vaporized. [Illustration: Fig. 219. Pair of Enclosed Fuses] Fuses of the enclosed type, with or without filling, are widely used in power circuits generally and are recommended by fire insurance bodies. Fig. 219 illustrates an arrester having a fuse of the enclosed type, this example being that of the H. W. Johns-Manville Company. [Illustration Fig. 220. Bank of Enclosed Fuses] In telephony it is frequently necessary to mount a large number of fuses or other protective devices together in a restricted space. In Fig. 220 a group of Western Electric tubular fuses, so mounted, is shown. These fuses have ordinarily a carrying capacity of 6 or 7 amperes. It is not expected that this arrester will blow because 6 or 7 amperes of abnormal currents are flowing through it and the apparatus to be protected. What is intended is that the fuse shall withstand lightning discharges and when a foreign current passes through it, other apparatus will increase that current enough to blow the fuse. It will be noticed that the fuses of Fig. 220 are open at the upper end, which is the end connected to the exposed wire of the line The fuses are closed at the lower end, which is the end connected to the apparatus. When the fuse blows, its discharge is somewhat muffled by the lining of the tube, but enough explosion remains so that the heated gases, in driving outward, tend to break the arc which is established through the vaporized metal. A pair of Cook tubular fuses in an individual mounting is shown in Fig. 221. Fuses of this type are not open at one end like a gun, but opportunity for the heated gases to escape exists at the caps. The tubes are made of wood, of lava, or of porcelain. Fig. 222 is another tubular fuse, the section showing the arrangement of asbestos lining which serves the two purposes of muffling the sound of the discharge and absorbing and cooling the resulting gases. [Illustration: Fig. 221. Pair of Wooden Tube Fuses] _Air-Gap vs. Fuse Arresters._ It is hoped that the student grasps clearly the distinction between the purposes of air-gap and fuse arresters. The air-gap arrester acts in response to high voltages, either of lightning or of high-tension power circuits. The fuse acts in response to a certain current value flowing through it and this minimum current in well-designed protectors for telephone lines is not very small. Usually it is several times larger than the maximum current apparatus in the line can safely carry. Fuses _can_ be made so delicate as to operate on the very smallest current which could injure apparatus and the earlier protective systems depended on such an arrangement. The difficulty with such delicate fuses is that they are not robust enough to be reliable, and, worse still, they change their carrying capacity with age and are not uniform in operation in different surroundings and at different temperatures. They are also sensitive to lightning discharges, which they have no power to stop or to divert. Protection Against Sneak Currents. For these reasons, a system containing fuses and air-gap arresters only, does not protect against abnormal currents which are continuous and small, though large enough to injure apparatus _because_ continuous. These currents have come to be known as sneak currents, a term more descriptive than elegant. Sneak currents though small, may, when allowed to flow for a long time through the winding of an electromagnet for instance, develop enough heat to char or injure the insulation. They are the more dangerous because insidious. [Illustration: Fig. 222. Tubular Fuse with Asbestos Filling] _Sneak-Current Arresters._ As typical of sneak-current arresters, Fig. 223 shows the principle, though not the exact form, of an arrester once widely used in telephone and signal lines. The normal path from the line to the apparatus is through a small coil of fine wire imbedded in sealing wax. A spring forms a branch path from the line and has a tension which would cause it to bear against the ground contact if it were allowed to do so. It is prevented from touching that contact normally by a string between itself and a rigid support. The string is cut at its middle and the knotted ends as thus cut are imbedded in the sealing wax which contains the coil. [Illustration: Fig. 223. Principle of Sneak-Current Arrester] A small current through the little coil will warm the wax enough to allow the string to part. The spring then will ground the line. Even so simple an apparatus as this operates with considerable accuracy. All currents below a certain critical amount may flow through the heating coil indefinitely, the heat being radiated rapidly enough to keep the wax from softening and the string from parting. All currents above this critical amount will operate the arrester; the larger the current, the shorter the time of operating. It will be remembered that the law of these heating effects is that the heat generated = _C^{2}Rt_, so that if a certain current operates the arrester in, say 40 seconds, twice as great a current should operate the arrester in 10 seconds. In other words, the time of operation varies inversely as the square of the current and inversely as the resistance. To make the arrester more sensitive for a given current--_i.e._, to operate in a shorter time--one would increase the resistance of the coil in the wax either by using more turns or finer wire, or by making the wire of a metal having higher specific resistance. The present standard sneak-current arrester embodies the two elements of the devices of Fig. 223: a _resistance_ material to transform the dangerous sneak current into localized heat; and a _fusible_ material softened by this heat to release some switching mechanism. The resistance material is either a resistance wire or a bit of carbon, the latter being the better material, although both are good. The fusible material is some alloy melting at a low temperature. Lead, tin, bismuth, and cadmium can be combined in such proportions as will enable the alloy to melt at temperatures from 140° to 180° F. Such an alloy is a solder which, at ordinary temperatures, is firm enough to resist the force of powerful springs; yet it will melt so as to be entirely fluid at a temperature much less than that of boiling water. [Illustration: Fig. 224. Heat Coil] _Heat Coil._ Fig. 224 shows a practical way of bringing the heating and to-be-heated elements together. A copper spool is wound with resistance wire. A metal pin is soldered in the bore of the spool by an easily melting alloy. When current heats the spool enough, the pin may slide or turn in the spool. It may slide or turn in many ways and this happily enables many types of arresters to result. For example, the pin may pull out, or push in, or push through, or rotate like a shaft in a bearing, or the spool may turn on it like a hub on an axle. Messrs. Hayes, Rolfe, Cook, McBerty, Kaisling, and many other inventors have utilized these combinations and motions in the production of sneak-current arresters. All of them depend on one action: the softening of a low-melting alloy by heat generated in a resistance. When a heat coil is associated with the proper switching springs, it becomes a sneak-current arrester. The switching springs always are arranged to ground the line wire. In some arresters, the line wire is cut off from the wire leading toward the apparatus by the same movement which grounds it. In others, the line is not broken at all, but merely grounded. Each method has its advantages. Complete Line Protection. Fig. 225 shows the entire scheme of protectors in an exposed line and their relation to apparatus in the central-office equipment and at the subscriber's telephone. The central-office equipment contains heat coils, springs, and carbon arresters. At some point between the central office and the subscriber's premises, each wire contains a fuse. At the subscriber's premises each wire contains other fuses and these are associated with carbon arresters. The figure shows a central battery equipment, in which the ringer of the telephone is in series with a condenser. A sneak-current arrester is not required at the subscriber's station with such equipment. Assume the line to meet an electrical hazard at the point _X_. If this be lightning, it will discharge to ground at the central office or at the subscriber's instrument or at both through the carbon arresters connected to that side of the line. If it be a high potential from a power circuit and of more than 350 volts, it will strike an arc at the carbon arrester connected to that wire of the line in the central office or at the subscriber's telephone or at both, if the separation of the carbons in those arresters is .005 inch or less. If the carbon arresters are separated by celluloid, it will burn away and allow the carbons to come together, extinguishing the arc. If they are separated by mica and one of the carbons is equipped with a globule of low-melting alloy, the heat of the arc will melt this, short-circuiting the gap and extinguishing the arc. The passage of current to ground at the arrester, however, will be over a path containing nothing but wire and the arrester. The resulting current, therefore, may be very large. The voltage at the arrester having been 350 volts or more, in order to establish the arc, short-circuiting the gap will make the current 7 amperes or more, unless the applied voltage miraculously falls to 50 volts or less. The current through the fuse being more than 7 amperes, it will blow promptly, opening the line and isolating the apparatus. It will be noted that this explanation applies to equipment at either end of the line, as the fuse lies between the point of contact and the carbon arrester. [Illustration: Fig. 225. Complete Line Protection] Assume, on the other hand, that the contact is made at the point _Y_. The central-office carbon arrester will operate, grounding the line and increasing the amount of current flowing. There being no fuse to blow, a worse thing will befall, in the overheating of the line wire and the probable starting of a fire in the central office. It is obvious, therefore, that a fuse must be located between the carbon arrester and any part of the line which is subject to contact with a potential which can give an abnormal current when the carbon arrester acts. Assume, as a third case, that the contact at the point _X_ either is with a low foreign potential or is so poor a contact that the difference of potential across the gap of the carbon arrester is lower than its arcing point. Current will tend to flow by the carbon arrester without operating it, but such a current must pass through the winding of the heat coil if it is to enter the apparatus. The sneak current may be large enough to overheat the apparatus if allowed to flow long enough, but before it has flowed long enough it will have warmed the heat-coil winding enough to soften its fusible alloy and to release springs which ground the line, just as did the carbon arrester in the case last assumed. Again the current will become large and will blow the fuse which lies between the sneak-current arrester and the point of contact with the source of foreign current. In this case, also, contact at the point _Y_ would have operated mechanism to ground the line at the central office, and, no fuse interposing, the wiring would have been overheated. _Exposed and Unexposed Wiring._ Underground cables, cables formed of rubber insulated wires, and interior wiring which is properly done, all may be considered to be wiring which is unexposed, that is, not exposed to foreign high potentials, discharges, sneak, or abnormal currents. _All other wiring_, such as bare wires, aërial cables, etc., should be considered as _exposed_ to such hazards and a fuse should exist in each wire between its exposed portion and the central office or subscriber's instrument. The rule of action, therefore, becomes: _The proper position of the fuse is between exposed and unexposed wiring._ It may appear to the student that wires in an aërial cable with a lead sheath--that sheath being either grounded or ungrounded--are not exposed to electrical hazards; in the case of the grounded sheath, this would presume that a contact between the cable and a high potential wire would result merely in the foreign currents going to ground through the cable sheath, the arc burning off the high-potential wire and allowing the contact to clear itself by the falling of the wire. If the assumption be that the sheath is not grounded, then the student may say that no current at all would flow from the high-potential wire. Both assumptions are wrong. In the case of the grounded sheath, the current flows to it at the contact with the high-potential wire; the lead sheath is melted, arcs strike to the wires within, and currents are led directly to the central office and to subscribers' premises. In the case of the ungrounded sheath, the latter charges at once through all its length to the voltage of the high-potential wire; at some point, a wire within the cable is close enough to the sheath for an arc to strike across, and the trouble begins. All the wires in the cable are endangered if the cross be with a wire of the primary circuit of a high-tension transmission line. Any series arc-light circuit is a high-potential menace. Even a 450-volt trolley wire or feeder can burn a lead-covered cable entirely in two in a few seconds. The authors have seen this done by the wayward trolley pole of a street car, one side of the pole touching the trolley wire and the extreme end just touching the telephone cable. The answer lies in the foregoing rule. Place the fuse between the wires which _can_ and the wires which _can not_ get into contact with high potentials. In application, the rule has some flexibility. In the case of a cable which is aërial as soon as it leaves the central office, place the fuses in the central office; in a cable wholly underground, from central office to subscriber--as, for example, the feed for an office building--use no fuses at all; in a cable which leaves the central office underground and becomes aërial, fuse the wires just where they change from underground to aërial. The several branches of an underground cable into aërial ones should be fused as they branch. Wires properly installed in subscribers' premises are considered unexposed. The position of the fuse thus is at or near the point of entrance of the wires into that building if the wires of the subscriber's line outside the premises are exposed, as determined by the definitions given. If the line is unexposed, by those definitions, no protector is required. If one is indicated, it should be used, as compliance with the best-known practice is a clear duty. Less than what is known to be best is not honest practice in a matter which involves life, limb, and indefinite degrees of property values. Protectors in central-battery subscribers' equipments need no sneak-current arresters, as the condenser reduces that hazard to a negligible amount. Magneto subscribers' equipments usually lack condensers in ringer circuits, though they may have them in talking circuits on party lines. The ringer circuit is the only path through the telephone set for about 98 per cent of the time. Sneak-current arresters, therefore, should be a part of subscribers' station protectors in magneto equipment, except in such rural districts as may have no lighting or power wires. When sneak-current arresters are so used the arrangement of the parts then is the same as in the central-office portion of Fig. 225. Types of Central-Office Protectors. A form of combined heat coil and air-gap arrester, widely used by Bell companies for central-office protection, is shown in Fig. 226. The two inner springs form the terminals for the two limbs of the metallic-circuit line, while the two outside springs are terminals for the continuation of the line leading to the switchboard. The heat coils, one on each side, are supported between the inner and outer springs. High-tension currents jump to ground through the air-gap arrester, while sneak currents permit the pin of the heat coil to slide within the sleeve, thus grounding the outside line and the line to the switchboard. [Illustration: Fig. 226. Sneak-Current and Air-Gap Arrester] _Self-Soldering Heat Coils._ Another form designed by Kaisling and manufactured by the American Electric Fuse Company is shown in Fig. 227. In this the pin in the heat coil projects unequally from the ends of the coil, and under the action of a sneak current the melting of the solder which holds it allows the outer spring to push the pin through the coil until it presses the line spring against the ground plate and at the same time opens the path to the switchboard. When the heat-coil pin assumes this new position it cools off, due to the cessation of the current, and _resolders_ itself, and need only be turned end for end by the attendant to be reset. Many are the variations that have been made on this self-soldering idea, and there has been much controversy as to its desirability. It is certainly a feature of convenience. [Illustration: Fig. 227. Self-Soldering Heat-Coil Arrester] Instead of using a wire-wound resistance element in heat-coil construction some manufacturers employ a mass of high-resistance material, interposed in the path of the current. The Kellogg Company has long employed for its sneak-current arrester a short graphite rod, which forms the resistance element. The ends of this rod are electroplated with copper to which the brass terminal heads are soldered. These heads afford means for making the connection with the proper retaining springs. [Illustration: Fig. 228. Cook Arrester] Another central-office protector, which uses a mass of special metal composition for its heat producing element is that designed by Frank B. Cook and shown in Fig. 228. In this the carbon blocks are cylindrical in form and specially treated to make them "self-cleaning." Instead of employing a self-soldering feature in the sneak-current arrester of this device, Cook provides for electrically resoldering them after operation, a clip being designed for holding the elements in proper position and passing a battery current through them to remelt the solder. In small magneto exchanges it is not uncommon to employ combined fuse and air-gap arresters for central-office line protection, the fuses being of the mica-mounted type already referred to. A group of such arresters, as manufactured by the Dean Electric Company, is shown in Fig. 229. [Illustration: Fig. 229. Mica Fuse and Air-Gap Arresters] Types of Subscribers' Station Protectors. Figs. 230 and 231 show types of subscribers' station protectors adapted to the requirements of central-battery and magneto systems. These, as has been said, should be mounted at or near the point of entrance of the subscriber's line into the premises, if the line is exposed outside of the premises. It is possible to arrange the fuses so that they will be safe and suitable for their purposes if they are mounted out-of-doors near the point of entrance to the premises. The sneak-current arrester, if one exists, and the carbon arrester also, must be mounted inside of the premises or in a protecting case, if outside, on account of the necessity of shielding both of these devices from the weather. Speaking generally, the wider practice is to put all the elements of the subscriber's station protector inside of the house. It is nearer to the ideal arrangement of conditions if the protector be placed immediately at the point of entrance of the outside wires into the building. [Illustration: Fig. 230. Western Electric Station Arrester] [Illustration: Fig. 231. Cook Arrester for Magneto Stations] _Ribbon Fuses_. A point of interest with relation to tubular fuses is that in some of the best types of such fuses, the resistance material is not in the form of a round wire but in the form of a flat ribbon. This arrangement disposes the necessary amount of fusible metal in a form to give the greatest amount of surface, while a round wire offers the least surface for a given weight of metal--a circle encloses its area with less periphery than any other figure. The reason for giving the fuse the largest possible surface area is to decrease the likelihood of the fuse being ruptured by lightning. The fact that such fuses do withstand lightning discharges much more thoroughly than round fuses of the same rating is an interesting proof of the oscillating nature of lightning discharges, for the density of the current of those discharges is greater on and near the surface of the conductor than within the metal and, therefore, flattening the fuse increases its carrying capacity for high-frequency currents, without appreciably changing its carrying capacity for direct currents. The reason its capacity for direct currents is increased at all by flattening it, is that the surface for the radiation of heat is increased. However, when enclosed in a tube, radiation of heat is limited, so that for direct currents the carrying capacity of fuses varies closely with the area of cross-section. City-Exchange Requirements. The foregoing has set down the requirements of good practice in an average city-exchange system. Nothing short of the general arrangement shown in Fig. 225 meets the usual assortment of hazards of such an exchange. It is good modern practice to distribute lines by means of cables, supplemented in part by short insulated drop wires twisted in pairs. Absence of bare wires reduces electrical hazards enormously. Nevertheless, hazards remain. Though no less than the spirit of this plan of protection should be followed, additional hazards may exist, which may require additional elements of protection. At the end of a cable, either aërial or underground, long open wires may extend into the open country as rural or long-distance circuits. If these be longer than a mile or two, in most regions they will be subjected to lightning discharges. These may be subjected to high-potential contacts as well. If a specific case of such exposure indicates that the cables may be in danger, the long open lines then are equipped with additional air-gap arresters at the point of junction of those open lines with the cable. Practice varies as to the type. Maintenance charges are increased if carbon arresters separated .005 inch are used, because of the cost of sending to the end of the long cable to clear the blocks from carbon dust after each slight discharge. Roughened metal blocks do not become grounded as readily as do carbon blocks. The occasions of visit to the arresters, therefore, usually follow actual heavy discharges through them. The recommendations and the practice of the American Telephone and Telegraph Company differ on this point, while the practice of other companies varies with the temperaments of the engineers. The American Company specifies copper-block arresters where long country lines enter cables, if those lines are exposed to lightning discharges only. The exposed line is called _long_ if more than one-half mile in length. If it is exposed to high-potential hazards, carbon blocks are specified instead of copper. Other specifications of that company have called for the use of copper-block arresters on lines exposed to hazards above 2,500 volts. [Illustration: ONE OF THE FOUR WINGS OF THE OLD KELLOGG DIVIDED MULTIPLE BOARD OF THE CUYAHOGA TELEPHONE COMPANY, CLEVELAND, OHIO Ultimate Capacity, 24,000 Lines. One of the Two Examples in the United States of a Multiple Switchboard Having an Ultimate Capacity over 18,000 Lines. Replaced Recently by a Kellogg Straight Multiple Board Having an Ultimate Capacity of 18,000 Lines and a Present Capacity of 10,000 Lines.] The freedom of metal-block arresters from dust troubles gives them a large economical advantage over carbon. For similar separations, the ratio of striking voltages between carbon blocks and metal blocks respectively is as 7 to 16. In certain regions of the Pacific Coast where the lightning hazard is negligible and the high tension hazard is great, metal-block arresters at the outer ends of cables give acceptable protection. High winds which drive snow or dust against bare wires of a long line, create upon or place upon those wires a charge of static electricity which makes its way from the line in such ways as it can. Usually it discharges across arresters and when this discharge takes place, the line is disturbed in its balance and loud noises are heard in the telephones upon it. [Fig. 232. Drainage Coils] A telephone line which for a long distance is near a high-tension transmission line may have electrostatic or electromagnetic potentials, or both, induced upon it. If the line be balanced in its properties, including balance by transposition of its wires, the electrostatic induction may neutralize itself. The electromagnetic induction still may disturb it. _Drainage Coils_. The device shown in Fig. 232, which amounts merely to an inductive leak to earth, is intended to cure both the snowstorm and electromagnetic induction difficulties. It is required that its impedance be high enough to keep voice-current losses low, while being low enough to drain the line effectively of the disturbing charges. Such devices are termed "drainage coils." Electrolysis. The means of protection against the danger due to chemical action, set forth in the preceding chapter, form such a distinct phase of the subject of guarding property against electrical hazards as to warrant treatment in a separate chapter devoted to the subject of electrolysis. [Illustration: MAIN EXCHANGE, CLEVELAND, OHIO. Largest Four-Party Selective Ringing Switchboard in the World. Kellogg Switchboard and Supply Co.] CHAPTER XX GENERAL FEATURES OF THE TELEPHONE EXCHANGE Up to this point only those classes of telephone service which could be given between two or more stations on a single line have been considered. Very soon after the practical conception of the telephone, came the conception of the telephone exchange; that is, the conception of centering a number of lines at a common point and there terminating them in apparatus to facilitate their interconnection, so that any subscriber on any line could talk with any subscriber on any other line. The complete equipment of lines, telephone instruments, and switching facilities by which the telephone stations of the community are given telephone service is called a telephone exchange. The building where a group of telephone lines center for interconnection is called a central office, and its telephonic equipment the central-office equipment. The terms telephone office and telephone exchange are frequently confused. Although a telephone office building may be properly referred to as a telephone exchange building, it is hardly proper to refer to the telephone office as a telephone exchange, as is frequently done. In modern parlance the telephone exchange refers not only to the central office and its equipment but to the lines and instruments connected therewith as well; furthermore, a telephone exchange may embrace a number of telephone offices that are interconnected by means of so-called trunk lines for permitting the communication of subscribers whose lines terminate in one office with those subscribers whose lines terminate in any other office. Since a given telephone exchange may contain one or more central offices, it is proper to distinguish between them by referring to an exchange which contains but a single central office as a single office exchange, and to an exchange which contains a plurality of central offices as a multi-office exchange. In telephone exchange working, three classes of lines are dealt with--subscribers' lines, trunk lines, and toll lines. Subscribers' Lines. The term subscriber is commonly applied to the patron of the telephone service. His station is, therefore, referred to as a subscriber's station, and the telephone equipment at any subscriber's station is referred to as a subscriber's station equipment. Likewise, a line leading from a central office to one or more subscribers' stations is called a subscriber's line. A subscriber's line may, as has been shown in a previous chapter, be an individual line if it serves but one station, or a party line if it serves to connect more than one station with the central office. Trunk Lines. A trunk line is a line which is not devoted to the service of any particular subscriber, but which may form a connecting link between any one of a group of subscribers' lines which terminate in one place and any one of a group of subscribers' lines which terminate in another place. If the two groups of subscribers' lines terminate in the same building or in the same switchboard, so that the trunk line forming the connecting link between them is entirely within the central-office building, it is called a local trunk line, or a local trunk. If, on the other hand, the trunk line is for connecting groups of subscribers' lines which terminate in different central offices, it is called an inter-office trunk. Toll Lines. A toll line is a telephone line for the use of which a special fee or toll is charged; that is, a fee that is not included in the charges made to the subscriber for his regular local exchange service. Toll lines extend from one exchange district to another, more or less remote, and they are commonly termed _local_ toll and _long-distance_ toll lines according to the degree of remoteness. A toll line, whether local or long-distance, may be looked upon in the nature of an inter-exchange trunk. Districts. The district in a given community which is served by a single central office is called an office district. Likewise, the district which is served by a complete exchange is called an exchange district. An exchange district may, therefore, consist of a number of central-office districts, just as an exchange may comprise a number of central offices. To illustrate, the entire area served by the exchange of the Chicago Telephone Company in Chicago, embracing the entire city and some of its suburbs, is the Chicago exchange district. The area served by one of the central offices, such as the Hyde Park office, the Oakland office, the Harrison office, or any of the others, is an office district. Switchboards. The apparatus at the central office by which the telephone lines are connected for conversation and afterwards disconnected, and by which the various other functions necessary to the giving of complete telephone service are performed, is called a switchboard. This may be simple in the case of small exchanges, or of vast complexity in the case of the larger exchanges. Sometimes the switchboards are of such nature as to require the presence of operators, usually girls, to connect and disconnect the line and perform the other necessary functions, and such switchboards, whether large or small, are termed _manual_. Sometimes the switchboards are of such a nature as not to require the presence of operators, the various functions of connection, disconnection, and signaling being performed by the aid of special forms of apparatus which are under the control of the subscriber who makes the call. Such switchboards are termed _automatic_. Of recent years there has appeared another class of switchboards, employing in some measure the features of the automatic and in some measure those of the manual switchboard. These boards are commonly referred to as _semi-automatic_ switchboards, presumably because they are supposed to be half automatic and half manual. _Manual_. Manual switchboards may be subdivided into two classes according to the method of distributing energy for talking purposes. Thus we may have _magneto_ switchboards, which are those capable of serving lines equipped with magneto telephones, local batteries being used for talking purposes. On the other hand, we may have _common-battery_ switchboards, adapted to connect lines employing common-battery telephones in which all the current for both talking and signaling is furnished from the central office. In still another way we may classify manual switchboards if the method of distributing the energy for talking and signaling purposes is ignored. Thus, entirely irrespective of whether the switchboards are adapted to serve common-battery or local-battery lines, we may have non-multiple switchboards and multiple switchboards. The term _multiple_ switchboard is applied to that class of switchboards in which the connection terminals or jacks for all the lines are repeated at intervals along the face of the switchboard, so that each operator may have within her reach a terminal for each line and may thus be able to complete by herself any connection between two lines terminating in the switchboard. The term _non-multiple_ switchboard is applied to that class of boards where the provision for repeating the line terminals at intervals along the face of the board is not employed, but where, as a consequence, each line has but a single terminal on the face of the board. Non-multiple switchboards have their main use in small exchanges where not more than a few hundred lines terminate. Where such is the case, it is an easy matter to handle all the traffic by one, two, or three operators, and as all of these operators may reach all over the face of the switchboard, there is no need for giving any line any more than one connection terminal. Such boards may be called _simple_ switchboards. There is another type of non-multiple switchboard adaptable for use in larger exchanges than the simple switchboard. A correct idea of the fundamental principle involved in these may be had by imagining a row of simple switchboards each containing terminals or jacks for its own group of lines. In order to provide for the connection of a line in one of these simple switchboards with a line in another one, out of reach of the operator at the first, short connecting lines extending between the two switchboards are provided, these being called _transfer_ or _trunk_ lines. In order that connections may be made between any two of the simple boards, a group of transfer lines is run from each board to every other one. In such switchboards an operator at one of the boards or positions may complete the connection herself between any two lines terminating at her own board. If, however, the line called for terminates at another one of the boards, the operator makes use of the transfer or trunk line extending to that board, and the operator at this latter board completes the connection, so that the two subscribers' lines are connected through the trunk or transfer line. A distinguishing feature, therefore, in the operation of so-called transfer switchboards, is that an operator can not always complete a connection herself, the connection frequently requiring the attention of two operators. Transfer systems are not now largely used, the multiple switchboard having almost entirely supplanted them in manual exchanges of such size as to be beyond the limitation of the simple switchboard. At multi-office manual exchanges, however, where there are a number of multiple switchboards employed at various central offices, the same sort of a requirement exists as that which was met by the provision of trunk lines between the various simple switchboards in a transfer system. Obviously, the lines in one central office must be connected to those of another in order to give universal service in the community in which the exchange operates. For this purpose inter-office trunk lines are used, the arrangement being such that when an operator at one office receives a call for a subscriber in another office, she will proceed to connect the calling subscriber's line, not directly with the line of the called subscriber because that particular line is not within her reach, but rather with a trunk line leading to the office in which the called-for subscriber's line terminates; having done this she will then inform an operator at that second office of the connection desired, usually by means of a so-called order-wire circuit. The connection between the trunk line so used and the line of the called-for subscriber will then be completed by the connecting link or trunk line extending between the two offices. In such cases the multiple switchboard at each office is divided into two portions, termed respectively the _A_ board and the _B_ board. Each of these boards, with the exception that will be pointed out in a subsequent chapter, is provided with a full complement of multiple jacks for all of the lines entering that office. At the _A_ board are located operators, called _A_ operators, who answer all the calls from the subscribers whose lines terminate in that office. In the case of calls for lines in that same office, they complete the connection themselves without the assistance of the other operators. On the other hand, the calls for lines in another office are handled through trunk lines leading to that other office, as before described, and these trunk lines always terminate in the _B_ board at that office. The _B_ operators are, therefore, those operators who receive the calls over trunk lines and complete the connection with the line of the subscriber desired. To define these terms more specifically, an _A_ board is a multiple switchboard in which the subscriber's lines of a given office district terminate. For this reason the _A_ board is frequently referred to as a subscribers' board, and the operators who work at these boards and who answer the calls of the subscribers are called _A_ operators or subscribers' operators. _B_ boards are switchboards in which terminate the incoming ends of the trunk lines leading from other offices in the same exchange. These boards are frequently called incoming trunk boards, or merely trunk boards, and the operators who work at them and who receive the directions from the _A_ operators at the other boards are called _B_ operators, or incoming trunk operators. The circuits which are confined wholly to the use of operators and over which the instructions from one operator to another are sent, as in the case of the _A_ operator giving an order for a connection to a _B_ operator at another switchboard, are designated _call circuits_ or _order wire circuits_. Sometimes trunk lines are so arranged that connections may be originated at either of their ends. In other cases they are so arranged that one group of trunk lines connecting two offices is for the traffic in one direction only, while another group leading between the same two offices is for handling only the traffic in the other direction. Trunk lines are called _one-way_ or _two-way_ trunks, according to whether they handle the traffic in one direction or in two. A trunking system, where the same trunks handle traffic both ways, is called a _single-track system_; and, on the other hand, a system in which there are two groups of trunks, one handling traffic in one direction and the other in the other, is called a _double-track system_. This nomenclature is obviously borrowed from railroad practice. There is still another class of manual switchboards called the _toll board_ of which it will be necessary to treat. Telephone calls made by one person for another within the limits of the same exchange district are usually charged for either by a flat rate per month, or by a certain charge for each call. This is usually regardless of the duration of the conversation following the call. On the other hand, where a call is made by one party for another outside of the limits of the exchange district and, therefore, in some other exchange district, a charge is usually made, based on the time that the connecting long-distance line is employed. Such calls and their ensuing conversations are charged for at a very much higher rate than the purely local calls, this rate depending on the distance between the stations involved. The making up of connections between a long-distance and a local line is usually done by means of operators other than those employed in handling the local calls, who work either by means of special equipment located on the local board, or by means of a separate board. Such equipments for handling long-distance or toll traffic are commonly termed toll switchboards. They differ from local boards (a) in that they are arranged for a very much smaller number of lines; (b) in that they have facilities by which the toll operator may make up the connections with a minimum amount of labor on the part of the assisting local operators; and (c) in that they have facilities for recording the identification of the parties and timing the conversations taking place over the toll lines, so that the proper charge may be made to the proper subscriber. CHAPTER XXI THE SIMPLE MAGNETO SWITCHBOARD Definitions. As already stated those switchboards which are adapted to work in conjunction with magneto telephones are called magneto switchboards. The signals on such switchboards are electromagnetic devices capable of responding to the currents of the magneto generators at the subscribers' stations. Since, as a rule, magneto telephones are equipped with local batteries, it follows that the magneto switchboard does not need to be arranged for supplying the subscribers' stations with talking current. This fact is accountable for magneto switchboards often being referred to as local-battery switchboards, in contradistinction to common-battery switchboards which are equipped so as to supply the connected subscribers' stations with talking current. The term _simple_ as applied in the headings of this and the next chapter, is employed to designate switchboards adapted for so small a number of lines that they may be served by a single or a very small group of operators; each line is provided with but a single connection terminal and all of them, without special provision, are placed directly within the reach of the operator, or operators if there are more than one. This distinction will be more apparent under the discussion of transfer and multiple switchboards. Mode of Operation. The cycle of operation of any simple manual switchboard may be briefly outlined as follows: The subscriber desiring a connection transmits a signal to the central office, the operator seeing the signal makes connection with the calling line and places herself in telephonic communication with the calling subscriber to receive his orders; the operator then completes the connection with the line of the called subscriber and sends ringing current out on that line so as to ring the bell of that subscriber; the two subscribers then converse over the connected lines and when the conversation is finished either one or both of them may send a signal to the central office for disconnection, this signal being called a clearing-out signal; upon receipt of the clearing-out signal, the operator disconnects the two lines and restores all of the central-office apparatus involved in the connection to its normal position. Component Parts. Before considering further the operation of manual switchboards it will be well to refer briefly to the component pieces of apparatus which go to make up a switchboard. _Line Signal._ The line signal in magneto switchboards is practically always in the form of an electromagnetic annunciator or drop. It consists in an electromagnet adapted to be included in the line circuit, its armature controlling a latch, which serves to hold the drop or shutter or target in its raised position when the magnet is not energized, and to release the drop or shutter or target so as to permit the display of the signal when the magnet is energized. The symbolic representation of such an electromagnetic drop is shown in Fig. 233. [Illustration: Fig. 233. Drop Symbol] _Jacks and Plugs._ Each line is also provided with a connection terminal in the form of a switch socket. This assumes many forms, but always consists in a cylindrical opening behind which are arranged one or more spring contacts. The opening forms a receptacle for plugs which have one or more metallic terminals for the conductors in the flexible cord in which the plug terminates. The arrangement is such that when a plug is inserted into a jack the contacts on the plug will register with certain of the contacts in the jack and thus continue the line conductors, which terminate in the jack contacts, to the cord conductors, which terminate in the plug contacts. Usually also when a plug is inserted certain of the spring contacts in the jack are made to engage with or disengage other contacts in the jack so as to make or break auxiliary circuits. [Illustration: Fig. 234. Spring Jack] A simple form of spring jack is shown in section in Fig. 234. In Fig. 235 is shown a sectional view of a plug adapted to co-operate with the jack of Fig. 234. In Fig. 236 the plug is shown inserted into the jack. The cylindrical portion of the jack is commonly called the _sleeve_ or _thimble_ and it usually forms one of the main terminals of the jack; the spring, forming the other principal terminal, is called the _tip spring_, since it engages the tip of the plug. The tip spring usually rests on another contact which may be termed the _anvil_. When the plug is inserted into the jack as shown in Fig. 236, the tip spring is raised from contact with this anvil and thus breaks the circuit leading through it. It will be understood that spring jacks are not limited to three contacts such as shown in these figures nor are plugs limited to two contacts. Sometimes the plugs have three, and even more, contacts, and frequently the jacks corresponding to such plugs have not only a contact spring adapted to register with each of the contacts of the plug, but several other auxiliary contacts also, which will be made or broken according to whether the plug is inserted or withdrawn from the jack. Symbolic representations of plugs and jacks are shown in Fig. 237. These are employed in diagrammatic representations of circuits and are supposed to represent the essential elements of the plugs and jacks in such a way as to be suggestive of their operation. It will be understood that such symbols may be greatly modified to express the various peculiarities of the plugs and jacks which they represent. [Illustration: Fig. 235. Plug] [Illustration: Fig. 236. Plug and Jack] [Illustration: Fig. 237. Jack and Plug Symbols] _Keys_. Other important elements of manual switchboards are ringing and listening keys. These are the devices by means of which the operator may switch the central-office generator or her telephone set into or out of the circuit of the connected lines. The details of a simple ringing and listening key are shown in Fig. 238. This consists of two groups of springs, one of four and one of six, the springs in each group being insulated from each other at their points of mounting. Two of these springs _1_ and _2_ in one group--the ringing group--are longer than the others, and act as movable levers engaging the inner pair of springs _3_ and _4_ when in their normal positions, and the outer pair _5_ and _6_ when forced into their alternate positions. Movement is imparted to these springs by the action of a cam which is mounted on a lever, manipulated by the operator. When this lever is moved in one direction the cam presses the two springs _1_ and _2_ apart, thus causing them to disengage the springs _3_ and _4_ and to engage the springs _5_ and _6_. [Illustration: Fig. 238. Ringing and Listening Key] The springs of the other group constitute the switching element of the listening key and are very similar in their action to those of the ringing key, differing in the fact that they have no inner pair of springs such as _3_ and _4_. The two long springs _7_ and _8_, therefore, normally do not rest against anything, but when the key lever is pressed, so as to force the cam between them, they are made to engage the two outer springs _9_ and _10_. [Illustration: Fig. 239. Ringing-and Listening-Key Symbols] The design and construction of ringing and listening keys assume many different forms. In general, however, they are adapted to do exactly the same sort of switching operations as that of which the device of Fig. 238 is capable. Easily understood symbols of ringing and listening keys are shown in Fig. 239; the cam member which operates on the two long springs is usually omitted for ease of illustration. It will be understood in considering these symbols, therefore, that the two long curved springs usually rest against a pair of inner contacts in case of the ringing key or against nothing at all in case of the listening key, and that when the key is operated the two springs are assumed to be spread apart so as to engage the outer pair of contacts with which they are respectively normally disconnected. _Line and Cord Equipments._ The parts of the switchboard that are individual to the subscriber's line are termed the _line equipment;_ this, in the case of a magneto switchboard, consists of the line drop and the jack together with the associated wiring necessary to connect them properly in the line circuit. The parts of the switchboard that are associated with a connecting link--consisting of a pair of plugs and associated cords with their ringing and listening keys and clearing-out drop--are referred to as a _cord equipment_. The circuit of a complete pair of cords and plugs with their associated apparatus is called a _cord circuit_. In order that there may be a number of simultaneous connections between different pairs of lines terminating in a switchboard, a number of cord circuits are provided, this number depending on the amount of traffic at the busiest time of the day. _Operator's Equipment._ A part of the equipment that is not individual to the lines or to the cord circuits, but which may, as occasion requires, be associated with any of them is called the _operator's equipment_. This consists of the operator's transmitter and receiver, induction coil, and battery connections together with the wiring and other associated parts necessary to co-ordinate them with the rest of the apparatus. Still another part of the equipment that is not individual to the lines nor to the cord circuits is the calling-current generator. This may be common to the entire office or a separate one may be provided for each operator's position. Operation in Detail. With these general statements in mind we may take up in some detail the various operations of a telephone system wherein the lines center in a magneto switchboard. This may best be done by considering the circuits involved, without special regard to the details of the apparatus. The series of figures showing the cycle of operations of the magneto switchboard about to be discussed are typical of this type of switchboard almost regardless of make. The apparatus is in each case represented symbolically, the representations indicating type rather than any particular kind of apparatus within the general class to which it belongs. _Normal Condition of Line._ In Fig. 240 is shown the circuit of an ordinary magneto line. The subscriber's sub-station apparatus, shown at the left, consists of the ordinary bridging telephone but might with equal propriety be indicated as a series telephone. The subscriber's station is shown connected with the central office by the two limbs of a metallic-circuit line. One limb of the line terminates in the spring _1_ of the jack, and the other limb in the sleeve or thimble _2_ of the jack. The spring _1_ normally rests on the third contact or anvil _3_ in the jack, its construction being such that when a plug is inserted this spring will be raised by the plug so as to break contact with the anvil _3_. It is understood, of course, that the plug associated with this jack has two contacts, referred to respectively as the tip and the sleeve; the tip makes contact with the tip spring _1_ and the sleeve with the sleeve or thimble _2_. [Illustration: Fig. 240. Normal Condition of Line] The drop or line signal is permanently connected between the jack sleeve and the anvil _3_. As a result, the drop is normally bridged across the circuit of the line so as to be in a receptive condition to signaling current sent out by the subscriber. It is evident, however, that when the plug is inserted into the jack this connection between the line and the drop will be broken. In this normal condition of the line, therefore, the drop stands ready at the central office to receive the signal from the subscriber and the generator at the sub-station stands ready to be bridged across the circuit of the line as soon as the subscriber turns its handle. Similarly the ringer--the call-receiving device at the sub-station--is permanently bridged across the line so as to be responsive to any signal that may be sent out from the central office in order to call the subscriber. The subscriber's talking apparatus is, in this normal condition of the line, cut out of the circuit by the switch hook. _Subscriber Calling._ Fig. 241 shows the condition of the line when the subscriber at the sub-station is making a call. In turning his generator the two springs which control the connection of the generator with the line are brought into engagement with each other so that the generator currents may pass out over the line. The condition at the central office is the same as that of Fig. 240 except that the drop is shown with its shutter fallen so as to indicate a call. [Illustration: Fig. 241. Subscriber Calling] [Illustration: A SPECIALLY FORMED CABLE FOR KEY SHELF OF MONARCH SWITCHBOARD] _Operator Answering._ The next step is for the operator to answer the call and this is shown in Fig. 242. The subscriber has released the handle of his generator and the generator has, therefore, been automatically cut out of the circuit. He also has removed his receiver from its hook, thus bringing his talking apparatus into the line circuit. The operator on the other hand has inserted one of the plugs _P__{a} into the jack. This action has resulted in the breaking of the circuit through the drop by the raising of the spring _1_ from the anvil _3_, and also in the continuance of the line circuit through the conductors of the cord circuits. Thus, the upper limb of the line is continued by means of the engagement of the tip spring _1_ with the tip _4_ of the plug to the conducting strand _6_ of the cord circuit; likewise the lower limb of the line is continued by the engagement of the thimble _2_ of the jack with the sleeve contact _5_ of the plug _P__{a} to the strand _7_ of the cord circuit. The operator has also closed her listening key _L.K._ In doing so she has brought the springs _8_ and _9_ into engagement with the anvils _10_ and _11_ and has thus bridged her head telephone receiver with the secondary of her induction coil across the two strands _6_ and _7_ of the cord. Associated with the secondary winding of her receiver is a primary circuit containing a transmitter, battery, and the primary of the induction coil. It will be seen that the conditions are now such as to permit the subscriber at the calling station to converse with the operator and this conversation consists in the familiar "Number Please" on the part of the operator and the response of the subscriber giving the number of the line that is desired. Neither the plug _P__{c}, nor the ringing key _R.K._, shown in Fig. 242, is used in this operation. The clearing-out drop _C.O._ is bridged permanently across the strands _6-7_ of the cord, but is without function at this time; the fact that it is wound to a high resistance and impedance prevents its having a harmful effect on the transmission. [Illustration: Fig. 242. Operator Answering] It may be stated at this point that the two plugs of an associated pair are commonly referred to as the answering and calling plugs. The answering plug is the one which the operator always uses in answering a call as just described in connection with Fig. 242. The calling plug is the one which she next uses in connecting with the line of the called subscriber. It lies idle during the answering of a call and is only brought into play after the order of the calling subscriber has been given, in which case it is used in establishing connection with the called subscriber. [Illustration: Fig. 243. Operator Calling] _Operator Calling._ We may now consider how the operator calls the called subscriber. The condition existing for this operation is shown in Fig. 243. The operator after receiving the order from the calling subscriber inserts the calling plug _P__{c} into the jack of the line of the called station. This act at once connects the limbs of the line with the strands _6_ and _7_ of the cord circuit, and also cuts out the line drop of the called station, as already explained. The operator is shown in this figure as having opened her listening key _L.K._ and closed her ringing key _R.K._ As a result, ringing current from the central-office generator will flow out over the two ringing key springs _12_ and _13_ to the tip and sleeve contacts of the calling plug _P__{c}, then to the tip spring _1_ and the sleeve or thimble _2_ of the jack, and then to the two sides of the metallic-circuit line to the sub-station and through the bell there. This causes the ringing of the called subscriber's bell, after which the operator releases the ringing key and thereby allows the two springs _12_ and _13_ of that key to again engage their normal contacts _14_ and _15_, thus making the two strands _6_ and _7_ of the cord circuit continuous from the contacts of the answering plug _P__{a} to the contacts of the calling plug _P__{c}. This establishes the condition at the central office for conversation between the two subscribers. [Illustration: Fig. 244. Subscribers Connected for Conversation.] _Subscribers Conversing._ The only other thing necessary to establish a complete set of talking conditions between the two subscribers is for the called subscriber to remove his receiver from its hook, which he does as soon as he responds to the call. The conditions for conversation between the two subscribers are shown in Fig. 244. It is seen that the two limbs of the calling line are connected respectively to the two limbs of the called line by the two strands of the cord circuit, both the operator's receiver and the central-office generator being cut out by the listening and ringing keys, respectively. Likewise the two line drops are cut out of circuit and the only thing left associated with the circuit at the central office is the clearing-out drop _C. O._, which remains bridged across the cord circuit. This, like the two ringers at the respective connected stations, which also remain bridged across the circuit when bridging instruments are used, is of such high resistance and impedance that it offers practically no path to the rapidly fluctuating voice currents to leak from one side of the line circuit to the other. Fluctuating currents generated by the transmitter at the calling station, for instance, are converted by means of the induction coil into alternating currents flowing in the secondary of the induction coil at that station. Considering a momentary current as passing up through the secondary winding of the induction coil at the calling station, it passes through the receiver of that station through the upper limb of the line to the spring _1_ of the line jack belonging to that line at the central office; thence through the tip _4_ of the answering plug to the conductor _6_ of the cord; thence through the pair of contacts _14_ and _12_ forming one side of the ringing key to the tip _4_ of the calling plug; thence to the tip spring _1_ of the jack of the called subscriber's line; thence over the upper limb of his line through his receiver and through the secondary of the induction to one of the upper switch-hook contacts; thence through the hook lever to the lower side of the line, back to the central office and through the sleeve contact _2_ of the jack and the sleeve contact _5_ of the plug; thence through the other ringing key contacts _13_ and _15_; thence through the strand _7_ of the cord to the sleeve contact _5_ and the sleeve contact _2_ of the answering plug and jack, respectively; thence through the lower limb of the calling subscriber's line to the hook lever at his station; thence through one of the upper contacts of this hook to the secondary of the induction coil, from which point the current started. [Illustration: Fig. 245. Clearing-Out Signal] Obviously, when the called subscriber is talking to the calling subscriber the same path is followed. It will be seen that at any time the operator may press her listening key _L.K._, bridge her telephone set across the circuit of the two connected lines, and listen to the conversation or converse with either of the subscribers in case of necessity. _Clearing Out_. At the close of the conversation, either one or both of the subscribers may send a clearing-out signal by turning their generators after hanging up their receivers. This condition is shown in Fig. 245. The apparatus at the central office remains in exactly the same position during conversation as that of Fig. 244, except that the clearing-out drop shutter is shown as having fallen. The two subscribers are shown as having hung up their receivers, thus cutting out their talking apparatus, and as operating their generators for the purpose of sending the clearing-out signals. In response to this act the operator pulls down both the calling and the answering plug, thus restoring them to their normal seats, and bringing both lines to the normal condition as shown in Fig. 240. The line drops are again brought into operative relation with their respective lines so as to be receptive to subsequent calls and the calling generators at the sub-stations are removed from the bridge circuits across the line by the opening of the automatic switch contacts associated with those generators. _Essentials of Operation_. The foregoing sequence of operations while described particularly with respect to magneto switchboards is, with certain modifications, typical of the operation of nearly all manual switchboards. In the more advanced types of manual switchboards, certain of the functions described are sometimes done automatically, and certain other functions, not necessary in connection with the simple switchboard, are added. The essential mode of operation, however, remains the same in practically all manual switchboards, and for this reason the student should thoroughly familiarize himself with the operation and circuits of the simple switchboard as a foundation for the more complex and consequently more-difficult-to-understand switchboards that will be described later on. Commercial Types of Drops and Jacks. _Early Drops_. Coming now to the commercial types of switchboard apparatus, the first subject that presents itself is that of magneto line signals or drops. The very early forms of switchboard drops had, in most cases, two-coil magnets, the cores of which were connected at their forward ends by an iron yoke and the armature of which was pivoted opposite the rear end of the two cores. To the armature was attached a latch rod which projected forwardly to the front of the device and was there adapted to engage the upper edge of the hinged shutter, so as to hold it in its raised or undisplayed position when the armature was unattracted. Such a drop, of Western Electric manufacture, is shown in Fig. 246. [Illustration: Fig. 246 Old-Style Drop] Liability to Cross-Talk:--This type of drop is suitable for use only on small switchboards where space is not an important consideration, and even then only when the drop is entirely cut out of the circuit during conversation. The reason for this latter requirement will be obvious when it is considered that there is no magnetic shield around the winding of the magnet and no means for preventing the stray field set up by the talking currents in one of the magnets from affecting by induction the windings of adjacent magnets contained in other talking circuits. Unless the drops are entirely cut out of the talking circuit, therefore, they are very likely to produce cross-talk between adjacent circuits. Furthermore, such form of drop is obviously not economical of space, two coils placed side by side consuming practically twice as much room as in the case of later drops wherein single magnet coils have been made to answer the purpose. _Tubular Drops._ In the case of line drops, which usually can readily be cut out of the circuit during conversation, this cross-talk feature is not serious, but sometimes the line drops, and always the clearing-out drops must be left in connection with the talking circuit. On account of economy in space and also on account of this cross-talk feature, there has come into existence the so-called tubular or iron-clad drop, one of which is shown in section in Fig. 247. This was developed a good many years ago by Mr. E.P. Warner of the Western Electric Company, and has since, with modifications, become standard with practically all the manufacturing companies. In this there is but a single bobbin, and this is enclosed in a shell of soft Norway iron, which is closed at its front end and joined to the end of the core as indicated, so as to form a complete return magnetic path for the lines of force generated in the coil. The rear end of the shell and core are both cut off in the same plane and the armature is made in such form as to practically close this end of the shell. The armature carries a latch rod extending the entire length of the shell to the front portion of the structure, where it engages the upper edge of the pivoted shutter; this, when released by the latch upon the attraction of the armature, falls so as to display a target behind it. [Illustration: Fig. 247. Tubular Drop] [Illustration: Fig. 248. Strip of Tubular Drops] These drops may be mounted individually on the face of the switchboard, but it is more usual to mount them in strips of five or ten. A strip of five drops, as manufactured by the Kellogg Switchboard and Supply Company, is shown in Fig. 248. The front strip on which these drops are mounted is usually of brass or steel, copper plated, and is sufficiently heavy to provide a rigid support for the entire group of drops that are mounted on it. This construction greatly facilitates the assembling of the switchboard and also serves to economize space--obviously, the thing to economize on the face of a switchboard is space as defined by vertical and horizontal dimensions. These tubular drops, having but one coil, are readily mounted on 1-inch centers, both vertically and horizontally. Sometimes even smaller dimensions than this are secured. The greatest advantage of this form of construction, however, is in the absolute freedom from cross-talk between two adjacent drops. So completely is the magnetic field of force kept within the material of the shell, that there is practically no stray field and two such drops may be included in two different talking circuits and the drops mounted immediately adjacent to each other without producing any cross-talk whatever. _Night Alarm._ Switchboard drops in falling make but little noise, and during the day time, while the operator is supposed to be needed continually at the board, the visual signal which they display is sufficient to attract her attention. In small exchanges, however, it is frequently not practicable to keep an operator at the switchboard at night or during other comparatively idle periods, and yet calls that do arrive during such periods must be attended to. For this reason some other than a visual signal is necessary, and this need is met by the so-called night-alarm attachment. This is merely an arrangement by which the shutter in falling closes a pair of contacts and thus completes the circuit of an ordinary vibrating bell or buzzer which will sound until the shutter is restored to its normal position. Such contacts are shown in Fig. 249 at _1_ and _2_. Night-alarm contacts have assumed a variety of forms, some of which will be referred to in the discussion of other types of drops and jacks. [Illustration: Fig. 249. Drop with Night-Alarm Contacts] _Jack Mounting._ Jacks, like drops, though frequently individually mounted are more often mounted in strips. An individually mounted jack is shown in Fig. 250, and a strip of ten jacks in Fig. 251. In such a strip of jacks, the strips supporting the metallic parts of the various jacks are usually of hard rubber reinforced by brass so as to give sufficient strength. Various forms of supports for these strips are used by different manufacturers, the means for fastening them in the switchboard frame usually consisting of brass lugs on the end of the jack strip adapted to be engaged by screws entering the stationary portion of the iron framework; or sometimes pins are fixed in the framework, and the jack is held in place by nuts engaging screw-threaded ends on such pins. [Illustration: Fig. 250. Individual Jack] [Illustration: Fig. 251. Strip of Jacks] _Methods of Associating Jacks and Drops._ There are two general methods of arranging the drops and jacks in a switchboard. One of these is to place all of the jacks in a group together at the lower portion of the panel in front of the operator and all of the drops together in another group above the group of jacks. The other way is to locate each jack in immediate proximity to the drop belonging to the same line so that the operator's attention will always be called immediately to the jack into which she must insert her plug in response to the display of a drop. This latter practice has several advantages over the former. Where the drops are all mounted in one group and the jacks in another, an operator seeing a drop fall must make mental note of it and pick out the corresponding jack in the group of jacks. On the other hand, where the jacks and drops are mounted immediately adjacent to each other, the falling of a drop attracts the attention of the operator to the corresponding jack without further mental effort on her part. The immediate association of the drops and jacks has another advantage--it makes possible such a mechanical relation between the drop and its associated jack that the act of inserting the plug into the jack in making the connection will automatically and mechanically restore the drop to its raised position. Such drops are termed _self-restoring drops_, and, since a drop and jack are often made structurally a unitary piece of apparatus, they are frequently called _combined_ drops and jacks. _Manual vs. Automatic Restoration._. There has been much difference of opinion on the question of manual versus automatic restoration of drops. Some have contended that there is no advantage in having the drops restored automatically, claiming that the operator has plenty of time to restore the drops by hand while receiving the order from the calling subscriber or performing some of her other work. Those who think this way have claimed that the only place where an automatically restored drop is really desirable is where, on account of the lack of space on the front of the switchboard, the drops are placed on such a portion of the board as to be not readily reached by the operator. This resulted in the electrically restored drop, mention of which will be made later. Others have contended that even though the drop is mounted within easy reach of the operator, it is advantageous that the operator should be relieved of the burden of restoring it, claiming that even though there are times in the regular performance of the operator's duties when she may without interfering with other work restore the drops manually, such requirement results in a double use of her attention and in a useless strain on her which might better be devoted to the actual making of connections. Until recently the various Bell operating companies have adhered, in their small exchange work, to the manual restoring method, while most of the so-called independent operating companies have adhered to the automatic self-restoring drops. Methods of Automatic Restoration. Two general methods present themselves for bringing about the automatic restoration of the drop. First, the mechanical method, which is accomplished by having some moving part of the jack or of the plug as it enters the jack force the drop mechanically into its restored position. This usually means the mounting of the drop and the corresponding jack in juxtaposition, and this, in turn, has usually resulted in the unitary structure containing both the drop and the jack. Second, the electrical method wherein the plug in entering the jack controls a restoring circuit, which includes a battery or other source of energy and a restoring coil on the drop, the result being that the insertion of the plug into the jack closes this auxiliary circuit and thus energizes the restoring magnet, the armature of which pulls the shutter back into its restored position. This practice has been followed by Bell operating companies whenever conditions require the drop to be mounted out of easy reach of the operator; not otherwise. _Mechanical--Direct Contact with Plug._ One widely used method of mechanical restoration of drops, once employed by the Western Telephone Construction Company with considerable success, was to hang the shutter in such position that it would fall immediately in front of the jack so that the operator in order to reach the jack with the plug would have to push the plug directly against the shutter and thus restore it to its normal or raised position. In this construction the coil of the drop magnet was mounted directly behind the jack, the latch rod controlled by the armature reaching forward, parallel with the jack, to the shutter, which, as stated, was hung in front of the jack. This resulted in a most compact arrangement so far as the space utilization on the front of the board was concerned and such combined drops and jacks were mounted on about 1-inch centers, so that a bank of one hundred combined drops and jacks occupied a space only a little over 10 inches square. A modification of this scheme, as used by the American Electric Telephone Company, was to mount the drop immediately over the jack so that its shutter, when down, occupied a position almost in front of, but above, the jack opening. The plug was provided with a collar, which, as it entered the jack, engaged a cam on the base of the shutter and forced the latter mechanically into its raised position. Neither of these methods of restoring--_i.e._, by direct contact between the shutter or part of it and the plug or part of it--is now as widely used as formerly. It has been found that there is no real need in magneto switchboards for the very great compactness which the hanging of the shutter directly in front of the drop resulted in, and the tendency in later years has been to make the combined drops and jacks more substantial in construction at the expense of some space on the face of the switchboard. [Illustration: Fig. 252. Kellogg Drop and Jack] Kellogg Type:--A very widely used scheme of mechanical restoration is that employed in the Miller drop and jack manufactured by the Kellogg Switchboard and Supply Company, the principles of which may be understood in connection with Fig. 252. In this figure views of one of these combined drops and jacks in three different positions are shown. The jack is composed of the framework _B_ and the hollow screw _A_, the latter forming the sleeve or thimble of the jack and being externally screw-threaded so as to engage and bind in place the front end of the framework _B_. The jack is mounted on the lower part of the brass mounting strip _C_ but insulated therefrom. The tip spring of the jack is bent down as usual to engage the tip of the plug, as better shown in the lower cut of Fig. 252, and then continues in an extension _D_, which passes through a hole in the mounting plate _C_. This tip spring in its normal position rests against another spring as shown, which latter spring forms one terminal of the drop winding. The drop or annunciator is of tubular form, and the shutter is so arranged on the front of the mounting strip _C_ as to fall directly above the extension _D_ of the tip spring. As a result, when the plug is inserted into the jack, the upward motion of the tip spring forces the drop into its restored position, as indicated in the lower cut of the figure. These drops and jacks are usually mounted in banks of five, as shown in Fig. 253. [Illustration: Fig. 253. Strip of Kellogg Drops and Jacks] Western Electric Type:--The combined drop and jack of the Western Electric Company recently put on the market to meet the demands of the independent trade, differs from others principally in that it employs a spherical drop or target instead of the ordinary flat shutter. This piece of apparatus is shown in its three possible positions in Fig. 254. The shutter or target normally displays a black surface through a hole in the mounting plate. The sphere forming the target is out of balance, and when the latch is withdrawn from it by the action of the electromagnet it falls into the position shown in the middle cut of Fig. 254, thus displaying a red instead of a black surface to the view of the operator. When the operator plugs in, the plug engages the lower part of an =S=-shaped lever which acts on the pivoted sphere to restore it to its normal position. A perspective view of one of these combined line signals and jacks is shown in Fig. 255. A feature that is made much of in recently designed drops and jacks for magneto service is that which provides for the ready removal of the drop coil, from the rest of the structure, for repair. The drop and jack of the Western Electric Company, just described, embodies this feature, a single screw being so arranged that its removal will permit the withdrawal of the coil without disturbing any of the other parts or connections. The coil windings terminate in two projections on the front head of the spool, and these register with spring clips on the inside of the shell so that the proper connections for the coil are automatically made by the mere insertion of the coil into the shell. [Illustration: Fig. 254. Western Electric Drop and Jack] [Illustration: Fig. 255. Western Electric Drop and Jack] Dean Type:--The combined drop and jack of the Dean Electric Company is illustrated in Figs. 256 and 257. The two perspective views show the general features of the drop and jack and the method by which the magnet coil may be withdrawn from the shell. As will be seen the magnet is wound on a hollow core which slides over the iron core, the latter remaining permanently fixed in the shell, even though the coil be withdrawn. Fig. 258 shows the structural details of the jack employed in this combination and it will be seen that the restoring spring for the drop is not the tip spring itself, but another spring located above and insulated from it and mechanically connected therewith. [Illustration: Fig. 256. Dean Drop and Jack] [Illustration: Fig. 257. Dean Drop and Jack] [Illustration: Fig. 258. Details of Dean Jack] Monarch Type:--Still another combined drop and jack is that of the Monarch Telephone Manufacturing Company of Chicago, shown in sectional view in Fig. 259. This differs from the usual type in that the armature is mounted on the front end of the electromagnet, its latch arm retaining the shutter in its normal position when raised, and releasing it when depressed by the attraction of the armature. As is shown, there is within the core of the magnet an adjustable spiral spring which presses forward against the armature and which spring is compressed by the attraction of the armature of the magnet. The night-alarm contact is clearly shown immediately below the strip which supports the drop, this consisting of a spring adapted to be engaged by a lug on the shutter and pressed upwardly against a stationary contact when the shutter falls. The method of restoration of the shutter in this case is by means of an auxiliary spring bent up so as to engage the shutter and restore it when the spring is raised by the insertion of a plug into the jack. [Illustration: Fig. 259. Monarch Drop and Jack] _Code Signaling._ On bridging party lines, where the subscribers sometimes call other subscribers on the same line and sometimes call the switchboard so as to obtain a connection with another line, it is not always easy for the operator at the switchboard to distinguish whether the call is for her or for some other party on the line. On such lines, of course, code ringing is used and in most cases the operator's only way of distinguishing between calls for her and those for some sub-station parties on the line is by listening to the rattling noise which the drop armature makes. In the case of the Monarch drop the adjustable spring tension on the armature is intended to provide for such an adjustment as will permit the armature to give a satisfactory buzz in response to the alternating ringing currents, whether the line be long or short. [Illustration: Fig. 260. Code Signal Attachment] The Monarch Company provides in another way for code signaling at the switchboard. In some cases there is a special attachment, shown in Fig. 260, by means of which the code signals are repeated on the night-alarm bell. This is in the nature of a special attachment placed on the drop, which consists of a light, flat spring attached to the armature and forming one side of a local circuit. The other side of the circuit terminates in a fixture which is mounted on the drop frame and is provided with a screw, having a platinum point forming the other contact point; this allows of considerable adjustment. At the point where the screw comes in contact with the spring there is a platinum rivet. When an operator is not always in attendance, this code-signaling attachment has some advantages over the drop as a signal interpreter, in that it permits the code signals to be heard from a distance. Of course, the addition of spring contacts to the drop armature tends to complicate the structure and perhaps to cut down the sensitiveness of the drop, which are offsetting disadvantages. [Illustration: Fig. 261. Combined Drop and Ringer] For really long lines, this code signaling by means of the drop is best provided for by employing a combined drop and ringer, although in this case whatever advantages are secured by the mechanical restoration of the shutter upon plugging in are lost. Such a device as manufactured by the Dean Electric Company is shown in Fig. 261. In this the ordinary polarized ringer is used, but in addition the tapper rod carries a latch which, when vibrated by the ringing of the bell, releases a shutter and causes it to fall, thus giving a visual as well as an audible signal. _Electrical_. Coming now to the electrical restoration of drop shutters, reference is made to Fig. 262, which shows in side section the electrical restoring drop employed by the Bell companies and manufactured by the Western Electric Company. In this the coil _1_ is a line coil, and it operates on the armature _2_ to raise the latch lever _3_ in just the same manner as in the ordinary tubular drop. The latch lever _3_ acts, however, to release another armature _4_ instead of a shutter. This armature _4_ is pivoted at its lower end at the opposite end of the device from the armature _2_ and, by falling outwardly when released, it serves to raise the light shutter _5_. The restoring coil of this device is shown at _6_, and when energized it attracts the armature _4_ so as to pull it back under the catch of the latch lever _3_ and also so as to allow the shutter _5_ to fall into its normal position. The method of closing the restoring circuit is by placing coil _6_ in circuit with a local battery and with a pair of contacts in the jack, which latter contacts are normally open but are bridged across by the plug when it enters the jack, thus energizing the restoring coil and restoring the shutter. [Illustration: Fig. 262. Electrically Restored Drop] A perspective view of this Western Electric electrical restoring drop is shown in Fig. 263, a more complete mention being made of this feature under the discussion of magneto multiple switchboards, wherein it found its chief use. It is mentioned here to round out the methods that have been employed for accomplishing the automatic restoration of shutters by the insertion of the plug. [Illustration: Fig. 263. Electrically Restored Drop] Switchboard Plugs. A switchboard plug such as is commonly used in simple magneto switchboards is shown in Fig. 264 and also in Fig. 235. The tip contact is usually of brass and is connected to a slender steel rod which runs through the center of the plug and terminates near the rear end of the plug in a connector for the tip conductor of the cord. This central core of steel is carefully insulated from the outer shell of the plug by means of hard rubber bushings, the parts being forced tightly together. The outer shell, of course, forms the other conductor of the plug, called the sleeve contact. A handle of tough fiber tubing is fitted over the rear end of the plug and this also serves to close the opening formed by cutting away a portion of the plug shell, thus exposing the connector for the tip conductor. [Illustration: Fig. 264. Switchboard Plug] _Cord Attachment._ The rear end of the plug shell is usually bored out just about the size of the outer covering of the switchboard cord, and it is provided with a coarse internal screw thread, as shown. The cord is attached by screwing it tightly into this screw-threaded chamber, the screw threads in the brass being sufficiently coarse and of sufficiently small internal diameter to afford a very secure mechanical connection between the outer braiding of the cord and the plug. The connection between the tip conductor of the cord and the tip of the plug is made by a small machine screw connection as shown, while the connection between the sleeve conductor of the plug and the sleeve conductor of the cord is made by bending back the latter over the outer braiding of the cord before it is screwed into the shank of the plug. This results in the close electrical contact between the sleeve conductor of the cord and the inner metal surface of the shank of the plug. Switchboard Cords. A great deal of ingenuity has been exerted toward the end of producing a reliable and durable switchboard cord. While great improvement has resulted, the fact remains that the cords of manual switchboards are today probably the most troublesome element, and they need constant attention and repairs. While no two manufacturers build their cords exactly alike, descriptions of a few commonly used and successful cords may be here given. _Concentric Conductors._ In one the core is made from a double strand of strong lock stitch twine, over which is placed a linen braid. Then the tip conductor, which is of stranded copper tinsel, is braided on. This is then covered with two layers of tussah silk, laid in reverse wrappings, then there is a heavy cotton braid, and over the latter a linen braid. The sleeve conductor, which is also of copper tinsel, is then braided over the structure so formed, after which two reverse wrappings of tussah silk are served on, and this is covered by a cotton braid and this in turn by a heavy linen or polished cotton braid. The plug end of the cord is reinforced for a length of from 12 to 18 inches by another braiding of linen or polished cotton, and the whole cord is treated with melted beeswax to make it moisture-proof and durable. [Illustration: Fig. 265. Switchboard Cord] _Steel Spiral Conductors._ In another cord that has found much favor the two conductors are formed mainly by two concentric spiral wrappings of steel wire, the conductivity being reinforced by adjacent braidings of tinsel. The structure of such a cord is well shown in Fig. 265. Beginning at the right, the different elements shown are, in the order named, a strand of lock stitch twine, a linen braiding, into the strands of which are intermingled tinsel strands, the inner spiral steel wrapping, a braiding of tussah silk, a linen braiding, a loose tinsel braiding, the outer conductor of round spiral steel, a cotton braid, and an outside linen or polished cotton braid. The inner tinsel braiding and the inner spiral together form the tip conductor while the outer braiding and spiral together form the sleeve conductor. The cord is reinforced at the plug end for a length of about 14 inches by another braiding of linen. The tinsel used is, in each case, for the purpose of cutting down the resistance of the main steel conductor. These wrappings of steel wire forming the tip and sleeve conductors respectively, have the advantage of affording great flexibility, and also of making it certain that whatever strain the cord is subjected to will fall on the insulated braiding rather than on the spiral steel which has in itself no power to resist tensile strains. _Parallel Tinsel Conductors._ Another standard two-conductor switchboard cord is manufactured as follows: One conductor is of very heavy copper tinsel insulated with one wrapping of sea island cotton, which prevents broken ends of the tinsel or knots from piercing through and short-circuiting with the other conductor. Over this is placed one braid of tussah silk and an outer braid of cotton. This combines high insulation with considerable strength. The other conductor is of copper tinsel, not insulated, and this is laid parallel to the thrice insulated conductor already described. Around these two conductors is placed an armor of spring brass wire in spiral form, and over this a close, stout braid of glazed cotton. This like the others is reinforced by an extra braid at the plug end. Ringing and Listening Keys. The general principles of the ringing key have already been referred to. Ringing keys are of two general types, one having horizontal springs and the other vertical. [Illustration: Fig. 266. Horizontal-Spring Listening and Ringing Key] _Horizontal Spring Type._ Various Bell operating companies have generally adhered to the horizontal spring type except in individual and four-party-line keys. The construction of a Western Electric Company horizontal spring key is shown in Fig. 266. In this particular key, as illustrated, there are two cam levers operating upon three sets of springs. The cam lever at the left operates the ordinary ringing and listening set of springs according to whether it is pushed one way or the other. In ringing on single-party lines the cam lever at the left is the one to be used; while on two-party lines the lever at the left serves to ring the first party and the ringing key at the right the second party. In order that the operator may have an indication as to which station on a two-party line she has called, a small target _1_ carried on a lever _2_ is provided. This target may display a black or a white field, according to which of its positions it occupies. The lever _2_ is connected by the links _3_ and _4_ with the two key levers and the target is thus moved into one position or the other, according to which lever was last thrown into ringing position. It will be noticed that the springs are mounted horizontally and on edge. This on-edge feature has the advantage of permitting ready inspection of the contacts and of avoiding the liability of dust gathering between the contacts. As will be seen, at the lower end of each switch lever there is a roller of insulating material which serves as a wedge, when forced between the two long springs of any set, to force them apart and into engagement with their respective outer springs. [Illustration: Fig. 267. Vertical-Spring Listening and Ringing Key] _Vertical Spring Type._ The other type of ringing and listening key employing vertical springs is almost universally used by the various independent manufacturing companies. A good example of this is shown in Fig. 267, which shows partly in elevation and partly in section a double key of the Monarch Company. The operation of this is obvious from its mode of construction. The right-hand set of springs of the right-hand key in this cut are the springs of the listening key, while the left-hand set of the right-hand key are those of the calling-plug ringing key. The left-hand set of the left-hand key may be those of a ring-back key on the answering plug, while the right-hand set of the left-hand key may be for any special purpose. It is obvious that these groups of springs may be grouped in different combinations or omitted in part, as required. This same general form of key is also manufactured by the Kellogg Company and the Dean Company, that of the Kellogg Company being illustrated in perspective, Fig. 268. The keys of this general type have the same advantages as those of the horizontal on-edge arrangement with respect to the gathering of dust, and while perhaps the contacts are not so readily get-at-able for inspection, yet they have the advantage of being somewhat more simple, and of taking up less horizontal space on the key shelf. [Illustration: Fig. 268. Vertical Listening and Ringing Key] [Illustration: Fig. 269. Four-Party Listening and Ringing Key] _Party-Line Ringing Keys._ For party-line ringing the key matter becomes somewhat more complicated. Usually the arrangement is such that in connection with each calling plug there are a number of keys, each arranged with respect to the circuits of the plug so as to send out the proper combination and direction of current, if the polarity system is used; or the proper frequency of current if the harmonic system is used; or the proper number of impulses if the step-by-step or broken-line system is used. The number of different kinds of arrangements and combinations is legion, and we will here illustrate only an example of a four-party line ringing key adapted for harmonic ringing. A Kellogg party-line listening and ringing key is shown in Fig. 269. In this, besides the regular listening key, are shown four push-button keys, each adapted, when depressed, to break the connection back of the key, and at the same time connect the proper calling generator with the calling plug. _Self-Indicating Keys._ A complication that has given a good deal of trouble in the matter of party-line ringing is due to the fact that it is sometimes necessary to ring a second or a third time on a party-line connection, because the party called may not respond the first time. The operator is not always able to remember which one of the four keys associated with the plug connected with the desired party she has pressed on the first occasion and, therefore, when it becomes necessary to ring again, she may ring the wrong party. This is provided for in a very ingenious way in the key shown in Fig. 269, by making the arrangement such that after a given key has been depressed to its full extent in ringing, and then released, it does not come quite back to its normal position but remains slightly depressed. This always serves as an indication to the operator, therefore, as to which key she depressed last, and in the case of a re-ring, she merely presses the key that is already down a little way. On the next call if she is required to press another one of the four keys, the one which remained down a slight distance on the last call will be released and the one that is fully depressed will be the one that remains down as an indication. Such keys, where the key that was last used leaves an indication to that effect, are called _indicating_ ringing keys. In other forms the indication is given by causing the key lever to move a little target which remains exposed until some other key in the same set is moved. The key shown in Fig. 266 is an example of this type. NOTE. The matter of automatic ringing and other special forms of ringing will be referred to and discussed at their proper places in this work, but at this point they are not pertinent as they are not employed in simple switchboards. Operator's Telephone Equipment. Little need be said concerning the matter of the operator's talking apparatus, _i.e._, the operator's transmitter and receiver, since as transmitters and receivers they are practically the same as those in ordinary use for other purposes. The watch-case receiver is nearly always employed for operators' purposes on account of its lightness and compactness. It is used in connection with a head band so as to be held continually at the operator's ear, allowing both of her hands to be free. The transmitter used by operators does not in itself differ from the transmitters employed by subscribers, but the methods by which it is supported differ, two general practices being followed. One of these is to suspend the transmitter by flexible conducting cords so as to be adjustable in a vertical direction. A good illustration of this is given in Fig. 270. The other method, and one that is coming into more and more favor, is to mount the transmitter on a light bracket suspended by a flexible band from the neck of the operator, a breast plate being furnished so that the transmitter will rest on her breast and be at all times within proper position to receive her speech. To facilitate this, a long curved mouthpiece is commonly employed, as shown clearly in Fig. 47. [Illustration: Fig. 270. Operator's Transmitter Suspension] _Cut-in Jack._ It is common to terminate that portion of the apparatus which is worn on the operator's person--that is, the receiver only if the suspended type of transmitter is employed, and the receiver and transmitter if the breast plate type of transmitter is employed--in a plug, and a flexible cord connecting the plug terminates with the apparatus. The portions of the operator's talking circuit that are located permanently in the switchboard cabinet are in such cases terminated in a jack, called an operator's _cut-in jack_. This is usually mounted on the front rail of the switchboard cabinet just below the key shelf. Such a cut-in jack is shown in Fig. 271 and it is merely a specialized form of spring jack adapted to receive the short, stout plug in which the operator's transmitter, or transmitter and receiver, terminate. By this arrangement the operator is enabled readily to connect or disconnect her talking apparatus, which is worn on her person, whenever she comes to the board for work or leaves it at the end of her work. A complete operator's telephone set, or that portion that is carried on the person of the operator, together with the cut-in plug, is shown in Fig. 272. [Illustration: Fig. 271. Operator's Cut-in Jack] [Illustration: Fig. 272. Operator's Talking Set] Circuits of Complete Switchboard. We may now discuss the circuits of a complete simple magneto switchboard. The one shown in Fig. 273 is typical. Before going into the details of this, it is well to inform the student that this general form of circuit representation is one that is commonly employed in showing the complete circuits of any switchboard. Ordinarily two subscribers' lines are shown, these connecting their respective subscribers' stations with two different line equipments at the central office. The jacks and signals of these line equipments are turned around so as to face each other, in order to clearly represent how the connection between them may be made by means of the cord circuit. The elements of the cord circuit are also spread out, so that the various parts occupy relative positions which they do not assume at all in practice. In other words it must be remembered that, in circuit diagrams, the relative positions of the parts are sacrificed in order to make clear the circuit connections. However, this does not mean that it is often not possible to so locate the pieces of apparatus that they will in a certain way indicate relative positions, as may be seen in the case of the drop and jack in Fig. 273, the drop being shown immediately above the jack, which is the position in which these parts are located in practice. [Illustration: Fig. 273. Circuit of Simple Magneto Switchboard] Little need be said concerning this circuit in view of what has already been said in connection with Figs. 240 to 245. It will be seen in the particular sub-station circuit here represented, that the talking apparatus is arranged in the usual manner and that the ringer and generator are so arranged that when the generator is operated the ringer will be cut out of circuit, while the generator will be placed across the circuit; while, when the generator is idle, the ringer is bridged across the circuit and the generator is cut out. The line terminates in each case in the tip and sleeve contacts of the jack, and in the normal condition of the jack the line drop is bridged across the line. The arrangement by which the drop is restored and at the same time cut out of circuit when the operator plugs in the jack, is obvious from the diagrammatic illustration. The cord circuit is the same as that already discussed, with the exception that two ringing keys are provided, one in connection with the calling plug, as is universal practice, and the other in connection with the answering plug as is sometimes practiced in order that the operator may, when occasion requires, ring back the calling subscriber without the necessity of changing the plug in the jack. The outer contacts of these two ringing keys are connected to the terminals of the ringing generator and, when either key is operated, the connection between the plug, on which the ringing is to be done, and the rest of the cord circuit will be broken, while the generator will be connected with the terminals of the plug. The listening key and talking apparatus need no further explanation, it being obvious that when the key is operated the subscriber's telephone set will be bridged across the cord circuit and, therefore, connected with either or both of the talking subscribers. [Illustration: Fig. 274. Night-Alarm Circuit] Night-Alarm Circuits. The circuit of Fig. 273, while referred to as a complete circuit, is not quite that. The night-alarm circuit is not shown. In order to clearly indicate how a single battery and bell, or buzzer, may serve in connecting a number of line drops, reference is made to Fig. 274 which shows the connection between three different line drops and the night-alarm circuit. The night-alarm apparatus consists in the battery _1_ and the buzzer, or bell, _2_. A switch _3_ adapted to be manually operated is connected in the circuit with the battery and the buzzer so as to open this circuit when the night alarm is not needed, thus making it inoperative. During the portions of the day when the operator is needed constantly at the board it is customary to leave this switch _3_ open, but during the night period when she is not required constantly at the board this switch is closed so that an audible signal will be given whenever a drop falls. The night-alarm contact _4_ on each of the drops will be closed whenever a shutter falls, and as the two members of this contact, in the case of each drop, are connected respectively with the two sides of the night-alarm circuit, any one shutter falling will complete the necessary conditions for causing the buzzer to sound, assuming of course that the switch _3_ is closed. _Night Alarm with Relay._ A good deal of trouble has been caused in the past by uncertainty in the closure of the night-alarm circuit at the drop contact. Some of the companies have employed the form of circuit shown in Fig. 275 to overcome this. Instead of the night-alarm buzzer being placed directly in the circuit that is closed by the drop, a relay _5_ and a high-voltage battery _6_ are placed in this circuit. The buzzer and the battery for operating it are placed in a local circuit controlled by this relay. It will be seen by reference to Fig. 275 that when the shutter falls, it will, by closing the contact _4_, complete the circuit from the battery _6_ through the relay _5_--assuming switch _3_ to be closed--and thus cause the operation of the relay. The relay, in turn, by pulling up its armature, will close the circuit of the buzzer _2_ through the battery _7_ and cause the buzzer to sound. [Illustration: Fig. 275. Night-Alarm Circuit with Relay] The advantage of this method over the direct method of operating the buzzer is that any imperfection in the night-alarm contact at the drop is much less likely to prevent the flow of current of the high-voltage battery _6_ than of the low-voltage battery _1_, shown in connection with Fig. 274. This is because the higher voltage is much more likely to break down any very thin bit of insulation, such as might be caused by a minute particle of dust or oxide between contacts that are supposed to be closed by the falling of the shutter. It has been common to employ for battery _6_ a dry-cell battery giving about 20 or 24 volts, and for the operation of the buzzer itself, a similar battery of about two cells giving approximately 3 volts. _Night-Alarm Contacts._ The night-alarm contact _4_ of the drop shown diagrammatically in Figs. 274 and 275 would, if taken literally, indicate that the shutter itself actually forms one terminal of the circuit and the contact against which it falls, the other. This has not been found to be a reliable way of closing the night-alarm contacts and this method is indicated in these figures and in other figures in this work merely as a convenient way of representing the matter diagrammatically. As a matter of fact the night-alarm contacts are ordinarily closed by having the shutter fall against one spring, which is thereby pressed into engagement with another spring or contact, as shown in Fig. 249. This method employs the shutter only as a means for mechanically causing the one spring to press against the other, the shutter itself forming no part of the circuit. The reason why it is not a good plan to have the shutter itself act as one terminal of the circuit is that this necessitates the circuit connections being led to the shutter through the trunnions on which the shutter is pivoted. This is bad because, obviously, the shutter must be loosely supported on its trunnions in order to give it sufficiently free movement, and, as is well known, loose connections are not conducive to good electrical contacts. Grounded-and Metallic-Circuit Lines. When grounded circuits were the rule rather than the exception, many of the switchboards were particularly adapted for their use and could not be used with metallic-circuit lines. These grounded-circuit switchboards provided but a single contact in the jack and a single contact on the plug, the cords having but a single strand reaching from one plug to the other. The ringing keys and listening keys were likewise single-contact keys rather than double. The clearing-out drop and the operator's talking circuit and the ringing generator were connected between the single strand of the cord and the ground as was required. The grounded-circuit switchboard has practically passed out of existence, and while a few of them may be in use, they are not manufactured at present. The reason for this is that while many grounded circuits are still in use, there are very few places where there are not some metallic-circuit lines, and while the grounded-circuit switchboard will not serve for metallic-circuit lines, the metallic-circuit switchboard will serve equally well for either metallic-circuit or grounded lines, and will interconnect them with equal facility. This fact will be made clear by a consideration of Figs. 276, 277, and 278. [Illustration: Fig. 276. Connection Between Metallic Lines] [Illustration: Fig. 277. Connection Between Grounded Lines] _Connection between Two Similar Lines._ In Fig. 276 a common magneto cord circuit is shown connecting two metallic-circuit lines; in Fig. 277 the same cord circuit is shown connecting two grounded lines. In this case the line wire _1_ of the left-hand line is, when the plugs are inserted, continued to the tip of the answering plug, thence through the tip strand of the cord circuit to the tip of the calling plug, then to the tip spring of the right-hand jack and out to the single conductor of that line. The entire sleeve portion of the cord circuit becomes grounded as soon as the plugs are inserted in the jacks of such a line. Hence, we see that the sleeve contacts of the plug and the sleeve conductor of the cord are connected to ground through the permanent ground connection of the sleeve conductors of the jack as soon as the plug is inserted into the jack. Thus, when the cord circuit of a metallic-circuit switchboard is used to connect two grounded circuits together, the tip strand of the cord is the connecting link between the two conductors, while the sleeve strand of the cord merely serves to ground one side of the clearing-out drop and one side each of the operator's telephone set and the ringing generator when their respective keys are operated. _Connection between Dissimilar Lines._ Fig. 278 shows how the same cord circuit and the same arrangement of line equipment may be used for connecting a grounded line to a metallic-circuit line. The metallic circuit line is shown on the left and the grounded line on the right. When the two plugs are inserted into the respective jacks of this figure, the right-hand conductor of the metallic circuit shown on the left will be continued through the tip strand of the cord circuit to the line conductor of the grounded line shown on the right. The left-hand conductor of the metallic-circuit line will be connected to ground because it will be continued through the sleeve strand of the cord circuit to the sleeve contact of the calling plug and thence to the sleeve contact of the jack of the grounded line, which sleeve contact is shown to be grounded. The talking circuit between the two connected lines in this case may be traced as follows: From the subscriber's station at the left through the right-hand limb of the metallic-circuit line, through the tip contact and tip conductor of the cord circuit, to the single limb of the grounded-circuit line, thence to the sub-station of that line and through the talking apparatus there to ground. The return path from the right-hand station is by way of ground to the ground connection at the central office, thence to the sleeve contact of the grounded line jack, through the sleeve conductor of the cord circuit, to the sleeve contact of the metallic-circuit line jack, and thence by the left-hand limb of the metallic-circuit line to the subscriber's station. [Illustration: Fig. 278. Connection Between Dissimilar Lines] A better way of connecting a metallic-circuit line to a grounded line is by the use of a special cord circuit involving a repeating coil, such a connection being shown in Fig. 279. The cord circuit in this case differs in no respect from those already shown except that a repeating coil is associated with it in such a way as to conductively divide the answering side from the calling side. Obviously, whatever currents come over the line connected with the answering plug will pass through the windings _1_ and _2_ of this coil and will induce corresponding currents in the windings _3_ and _4_, which latter currents will pass out over the circuit of the line connected with the calling plug. When a grounded circuit is connected to a metallic circuit in this manner, no ground is thrown onto the metallic circuit. The balance of the metallic circuit is, therefore, maintained. To ground one side of a metallic circuit frequently so unbalances it as to cause it to become noisy, that is, to have currents flowing in it, by induction or from other causes, other than the currents which are supposed to be there for the purpose of conveying speech. [Illustration: Fig. 279. Connection of Dissimilar Lines through Repeating Coil] _Convertible Cord Circuits._ The consideration of Fig. 279 brings us to the subject of so-called convertible cord circuits. Some switchboards, serving a mixture of metallic and grounded lines, are provided with cord circuits which may be converted at will by the operator from the ordinary type shown in Fig. 276 to the type shown in Fig. 279. The advantage of this will be obvious from the following consideration. When a call originates on any line, either grounded or metallic, the operator does not know which kind of a line is to be called for. She, therefore, plugs into this line with any one of her answering plugs and completes the connection in the usual way. If the call is for the same kind of a circuit as that over which the call originated, she places the converting key in such a position as will connect the conductors of the cord circuit straight through; while if the connection is for a different kind of a line than that on which the call originated she throws the converting key into such a position as to include the repeating coil. A study of Fig. 280 will show that when the converting key, which is commonly referred to as the repeating-coil key, is in one position, the cord conductors will be cut straight through, the repeating coil being left open in both its windings; and when it is thrown to its other position, the connection between the answering and calling sides of the cord circuit will be severed and the repeating coil inserted so as to bring about the same effects and circuit arrangements as are shown in Fig. 279. [Illustration: Fig. 280. Convertible Cord Circuit] Cord-Circuit Considerations. _Simple Bridging Drop Type._ The matter of cord circuits in magneto switchboards is deserving of much attention. So far as talking requirements are concerned, the ordinary form of cord circuit with a clearing-out drop bridged across the two strands is adequate for nearly all conditions except those where a grounded-and a metallic-circuit line are connected together, in which case the inclusion of a repeating coil has some advantages. [Illustration: Fig. 281. Bridging Drop-Cord Circuit] From the standpoint of signaling, however, this type of cord circuit has some disadvantages under certain conditions. In order to simplify the discussion of this and other cord-circuit matters, reference will be made to some diagrams from which the ringing and listening keys and talking apparatus have been entirely omitted. In Fig. 281 the regular bridging type of clearing-out drop-cord circuit is shown, this being the type already discussed as standard. For ordinary practice it is all right. Certain difficulties are experienced with it, however, where lines of various lengths and various types of sub-station apparatus are connected. For instance, if a long bridging line be connected with one end of this cord circuit and a short line having a low-resistance series ringer be connected with the other end, then a station on the long line may have some difficulty in throwing the clearing-out drop, because of the low-resistance shunt that is placed around it through the short line and the low-resistance ringer. In other words, the clearing-out drop is shunted by a comparatively low-resistance line and ringer and the feeble currents arriving from a distant station over the long line are not sufficient to operate the drop thus handicapped. The advent of the various forms of party-line selective signaling and the use of such systems in connection with magneto switchboards has brought in another difficulty that sometimes manifests itself with this type of cord circuit. If two ordinary magneto telephones are connected to the two ends of this cord circuit, it is obvious that when one of the subscribers has hung up his receiver and the other subscriber rings off, the bell of the other subscriber will very likely be rung even though the clearing-out drop operates properly; it would be better in any event not to have this other subscriber's bell rung, for he may understand it to be a recall to his telephone. When, however, a party line is connected through such a cord circuit to an ordinary line having bridging instruments, for instance, the difficulty due to ringing off becomes even greater. When the subscriber on the magneto line operates his generator to give the clearing-out signal, he is very likely to ring some of the bells on the other line and this, of course, is an undesirable thing. This may happen even in the case of harmonic bells on the party line, since it is possible that the subscriber on the magneto line in turning his generator will, at some phase of the operation, strike just the proper frequency to ring some one of the bells on the harmonic party line. It is obvious, therefore, that there is a real need for a cord circuit that will prevent _through ringing._ One way of eliminating the through-ringing difficulty in the type of cord circuit shown in Fig. 281 would be to use such a very low-wound clearing-out drop that it would practically short-circuit the line with respect to ringing currents and prevent them from passing on to the other line. This, however, is not a good thing to do, since a winding sufficiently low to shunt the effective ringing current would also be too low for good telephone transmission. [Illustration: Fig. 282. Series Drop-Cord Circuit] _Series Drop Type._ Another type of cord circuit that was largely used by the Stromberg-Carlson Telephone Manufacturing Company at one time is shown in Fig. 282. In this the clearing-out drop was not bridged but was placed in series in the tip side of the line and was shunted by a condenser. The resistance of the clearing-out drop was 1,000 ohms and the capacity of the condenser was 2 microfarads. It is obvious that this way of connecting the clearing-out drop was subject to the _ringing-through_ difficulty, since the circuit through which the clearing-out current necessarily passed included the telephone instrument of the line that was not sending the clearing-out signal. This form was also objectionable because it was necessary for the subscriber to ring through the combined resistance of two lines, and in case the other line happened to be open, no clearing-out signal would be received. While this circuit, therefore, was perhaps not quite so likely as the other to tie up the subscriber, that is, to leave him connected without the ability to send a clearing-out signal, yet it was sure to ring through, for the clearing-out drop could not be thrown without the current passing through the other subscriber's station. [Illustration: Fig. 283. Dean Non-Ring-Through Cord Circuit] _Non-Ring-Through Type._ An early attempt at a non-ring-through cord is shown in Fig. 283, this having once been standard with the Dean Electric Company. It made use of two condensers of 1 microfarad each, one in each side of the cord circuit. The clearing-out drop was of 500 ohms resistance and was connected from the answering side of the tip conductor to the calling side of the sleeve conductor. In this way whatever clearing-out current reached the central office passed through at least one of the condensers and the clearing-out drop. In order for the clearing-out current to pass on beyond the central office it was necessary for it to pass through the two condensers in series. This arrangement had the advantage of giving a positive ring-off, regardless of the condition of the connected line. Obviously, even if the line was short-circuited, the ringing currents from the other line would still be forced through the clearing-out drop on account of the high effective resistance of the 1-microfarad condenser connected in series with the short-circuited line. Also the clearing-out signal would be properly received if the connected line were open, since the clearing-out drop would still be directly across the cord circuit. This arrangement also largely prevented through ringing, since the currents would pass through the 1-microfarad condenser and the 500-ohm drop more readily than through the two condensers connected in series. [Illustration: Fig. 284. Monarch Non-Ring-Through Cord Circuit] In Fig. 284 is shown the non-ring-through arrangement of cord circuit adopted by the Monarch Company. In this system the clearing-out drop has two windings, either of which will operate the armature. The two windings are bridged across the cord circuit, with a 1/2-microfarad condenser in series in the tip strand between the two winding connections. While the low-capacity condenser will allow the high-frequency talking current to pass readily without affecting it to any appreciable extent, it offers a high resistance to a low-frequency ringing current, thus preventing it from passing out on a connected line and forcing it through one of the windings of the coil. There is a tendency to transformer action in this arrangement, one of the windings serving as a primary and the other as a secondary, but this has not prevented the device from being highly successful. A modification of this arrangement is shown in Fig. 285, wherein a double-wound clearing-out drop is used, and a 1/2-microfarad condenser is placed in series in each side of the cord circuit between the winding connections of the clearing-out drop. This circuit should give a positive ring-off under all conditions and should prevent through ringing except as it may be provided by the transformer action between the two windings on the same core. [Illustration: Fig. 285. Non-Ring-Through Cord Circuit] Another rather ingenious method of securing a positive ring-off and yet of preventing in a certain degree the undesirable ringing-through feature is shown in the cord circuit, Fig. 286. In this two non-inductive coils _1_ and _2_ are shown connected in series in the tip and sleeve strands of the coils, respectively. Between the neutral point of these two non-inductive windings is connected the clearing-out drop circuit. Voice currents find ready path through these non-inductive windings because of the fact that, being non-inductive, they present only their straight ohmic resistance. The impedance of the clearing-out drop prevents the windings being shunted across the two sides of the cord circuit. With this circuit a positive ring-off is assured even though the line connected with the one sending the clearing-out signal is short-circuited or open. If it is short-circuited, the shunt around the clearing-out drop will still have the resistance of two of the non-inductive windings included in it, and thus the drop will never be short-circuited by a very low-resistance path. Obviously, an open circuit in the line will not prevent the clearing-out signal being received. While this is an ingenious scheme, it is not one to be highly recommended since the non-inductive windings, in order to be effective so far as signaling is concerned, must be of considerable resistance and this resistance is in series in the talking circuit. Even non-inductive resistance is to be avoided in the talking circuit when it is of considerable magnitude and where there are other ways of solving the problem. [Illustration: Fig. 286. Cord Circuit with Differential Windings] _Double Clearing-out Type. _Some people prefer two clearing-out drops in each cord circuit, so arranged that the one will be responsive to currents sent from the line with which the answering plug is connected and the other responsive only to currents sent from the line with which the calling plug is connected. Such a scheme, shown in Fig. 287, is sometimes employed by the Dean, the Monarch, and the Kellogg companies. Two 500-ohm clearing-out drops of ordinary construction are bridged across the cord circuit and in each side of the cord circuit there is included between the drop connections a 1-microfarad condenser. Ringing currents originating on the line with which the answering plug is connected will pass through the clearing-out drop, which is across that side of the cord circuit, without having to pass through any condensers. In order to reach the other clearing-out drop the ringing current must pass through the two 1-microfarad condensers in series, this making in effect only 1/2-microfarad. As is well known, a 1/2-microfarad condenser not only transmits voice currents with ease but also offers a very high apparent resistance to ringing currents. With the double clearing-out drop system the operator is enabled to tell which subscriber is ringing off. If both shutters fall she knows that both subscribers have sent clearing-out signals and she, therefore, pulls down the connection without the usual precaution of listening to see whether one of the subscribers may be waiting for another connection. This double clearing-out system is analogous to the complete double-lamp supervision that will be referred to more fully in connection with common-battery circuits. There is not the need for double supervision in magneto work, however, that there is in common-battery work because of the fact that in magneto work the subscribers frequently fail to remember to ring off, this act being entirely voluntary on their part, while in common-battery work, the clearing-out signal is given automatically by the subscriber when he hangs up his receiver, thus accomplishing the desired end without the necessity of thoughtfulness on his part. [Illustration: Fig. 287. Double Clearing-Out Drops] Another form of double clearing-out cord circuit is shown in Fig. 288. In this the calling and the answering plugs are separated by repeating coils, a condenser of 1-microfarad capacity being inserted between each pair of windings on the two ends of the circuit. The clearing-out drops are placed across the calling and answering cords in the usual manner. The condenser in this case prevents the drop being short-circuited with respect to ringing currents and yet permits the voice currents to flow readily through it. The high impedance of the drop forces the voice currents to take the path through the repeating coil rather than through the drop. This circuit has the advantage of a repeating-coil cord circuit in permitting the connection of metallic and grounded lines without causing the unbalancing of the metallic circuits by the connection to them of the grounded circuits. [Illustration: Fig. 288. Double Clearing-Out Drops] Recently there has been a growing tendency on the part of some manufacturers to control their clearing-out signals by means of relays associated with cord circuits, these signals sometimes being ordinary clearing-out drops and sometimes incandescent lamps. [Illustration: Fig. 289. Relay-Controlled Clearing-Out Drop] In Fig. 289 is shown the cord circuit sometimes used by the L.M. Ericsson Telephone Manufacturing Company. A high-wound relay is normally placed across the cord and this, besides having a high-resistance and impedance winding has a low-resistance locking winding so arranged that when the relay pulls up its armature it will close a local circuit including this locking winding and local battery. When once pulled up the relay will, therefore, stay up due to the energizing of this locking coil. Another contact operated by the relay closes the circuit of a low-wound clearing-out drop placed across the line, thus bridging it across the line. The condition of high impedance is maintained across the cord circuit normally while the subscribers are talking; but when either of them rings off, the high-wound relay pulls up and locks, thus completing the circuit of the clearing-out drop across the cords. The subsequent impulses sent from the subscribers' generators operate this drop. The relay is restored or unlocked and the clearing-out drop disconnected from the cord circuit by means of a key which opens the locking circuit of the relay. This key is really a part of the listening key and serves to open this locking circuit whenever the listening key is operated. The clearing-out drop is also automatically restored by the action of the listening key, this connection being mechanical rather than electrical. Recall Lamp:--The Monarch Company sometimes furnishes what it terms a recall lamp in connection with the clearing-out drops on its magneto switchboards. The circuit arrangement is shown in Fig. 290, wherein the drop is the regular double-wound clearing-out drop like that of Fig. 284. The armature carries a contact spring adapted to close the local circuit of a lamp whenever it is attracted. The object of this is to give the subscriber, whose line still remains connected by a cord circuit, opportunity to recall the central office if the operator has not restored the clearing-out drop. [Illustration: Fig. 290. Cord Circuit with Recall Lamp] _Lamp-Signal Type._ There has been a tendency on the part of some manufacturing companies to advocate, instead of drop signals, incandescent lamp signals for the cord circuits, and sometimes for the line circuits on magneto boards. In most cases this may be looked upon as a "frill." Where line lamps instead of drops have been used on magneto switchboards, it has been the practice to employ, instead of a drop, a locking relay associated with each lamp, which was so arranged that when the relay was energized by the magneto current from the subscriber's station, it would pull up and lock, thus closing the lamp circuit. The local circuit, or locking circuit, which included the lamp was carried through a pair of contacts in the corresponding jacks so arranged that when the plug was inserted in answer to the call, this locking lamp circuit would be open, thereby extinguishing the lamp and also unlocking the relay. There seems to be absolutely no good reason why lamp signals should be substituted for mechanical drops in magneto switchboards. There is no need for the economy in space which the lamp signal affords, and the complications brought in by the locking relays, and the requirements for maintaining a local battery suitable for energizing the lamps are not warranted for ordinary cases. [Illustration: Fig. 291. Cord Circuit with Double Lamp Signals] In Fig. 291 is shown a cord circuit, adaptable to magneto switchboards, provided with double lamp signals instead of clearing-out drops. Two high-wound locking relays are bridged across the line, the cord strands being divided by 1-microfarad condensers. When the high-wound coil of either relay is energized by the magneto current from the subscriber's station, the relay pulls up and closes a locking circuit including a battery and a coil _2_, the contact _3_ of the locking relay, and also the contact _4_ of a restoring key. This circuit may be traced from the ground through battery, coil _2_, contact _3_ controlled by the relay, and contact _4_ controlled by the restoring key, and back to ground. In multiple with the locking coil _2_ is the lamp, which is illuminated, therefore, whenever the locking circuit is closed. Pressure on the restoring key breaks the locking circuit of either of the lamps, thereby putting out the lamp and at the same time restoring the locking relay to its normal position. _Lamps vs. Drops in Cord Circuits._ So much has been said and written about the advantages of incandescent lamps as signals in switchboards and about the merits of the common-battery method of supplying current to the subscribers, that there has been a tendency for people in charge of the operation of small exchanges to substitute the lamp for the drop in a magneto switchboard in order to give the general appearance of common-battery operations. There has also been a tendency to employ the common-battery system of operation in many places where magneto service should have been used, a mistake which has now been realized and corrected. In places where the simple magneto switchboard is the thing to use, the simpler it is the better, and the employment of locking relays and lamp signals and the complications which they carry with them, is not warranted. Switchboard Assembly. The assembly of all the parts of a simple magneto switchboard into a complete whole deserves final consideration. The structure in which the various parts are mounted, referred to as the cabinet, is usually of wood. _Functions of Cabinet._ The purpose of the cabinet is not only to form a support for the various pieces of apparatus but also to protect them from dust and mechanical injury, and to hold those parts that must be manipulated by the operator in such relation that they may be most convenient for use, and thus best adapted for carrying out their various functions. Other points to be provided for in the design of the cabinet and the arrangement of the various parts within are: that all the apparatus that is in any way liable to get out of order may be readily accessible for inspection and repairs; and that provision shall be made whereby the wiring of these various pieces of apparatus may be done in a systematic and simple way so as to minimize the danger of crossed, grounded, or open circuits, and so as to provide for ready repair in case any of these injuries do occur. _Wall-Type Switchboards._ The simplest form of switchboard is that for serving small communities in rural districts. Ordinarily the telephone industry in such a community begins by a group of farmers along a certain road building a line connecting the houses of several of them and installing their own instruments. This line is liable to be extended to some store at the village or settlement, thus affording communication between these farmers and the center of their community. Later on those residing on other roads do the same thing and connect their lines to the same store or central point. Then it is that some form of switchboard is established, and perhaps the storekeeper's daughter or wife is paid a small fee for attendance. [Illustration: Fig. 292. Wall Switchboard with Telephone] A switchboard well-adapted for this class of service where the number of lines is small, is shown in Fig. 292. In this the operator's talking apparatus and her calling apparatus are embodied in an ordinary magneto wall telephone. The switchboard proper is mounted alongside of this, and the two line binding posts of the telephone are connected by a pair of wires to terminals of the operator's plug, which plug is shown hanging from the left-hand portion of the switchboard. The various lines centering at this point terminate in the combined drops and jacks on the switchboard, of which there are 20 shown in this illustration. Beside the operator's plug there are a number of pairs of plugs shown hanging from the switchboard cabinet. These are connected straight through in pairs, there being no clearing-out drops or keys associated with them in the arrangement. Each line shown is provided with an extra jack, the purpose of which will be presently understood. The method of operation is as follows: When a subscriber on a certain line desires to get connection through the switchboard he turns his generator and throws the drop. The operator in order to communicate with him inserts the plug in which her telephone terminates into the jack, and removes her receiver from its hook. Having learned that it is for a certain subscriber on another line, she withdraws her plug from the jack of the calling line and inserts it into the jack of the called line, then, hanging up her receiver, she turns the generator crank in accordance with the proper code to call that subscriber. When that subscriber responds she connects the two lines by inserting the two plugs of a pair into their respective jacks, and the subscribers are thus placed in communication. The extra jack associated with each line is merely an open jack having its terminals connected respectively with the two sides of the line. Whenever an operator desires to listen in on two connected lines she does so by inserting the operator's plug into one of these extra jacks of the connected lines, and she may thus find out whether the subscribers are through talking or whether either one of them desires another connection. The drops in such switchboards are commonly high wound and left permanently bridged across the line so as to serve as clearing-out drops. The usual night-alarm attachment is provided, the buzzer being shown at the upper right-hand portion of the cabinet. [Illustration: Fig. 293. Combined Telephone and Switchboard] Another type of switchboard commonly employed for this kind of service is shown in Fig. 293, in which the telephone and the switchboard cabinet are combined. The operation of this board is practically the same as that of Fig. 292, although it has manually-restored drops instead of self-restoring drops; the difference between these two types, however, is not material for this class of service. For such work the operator has ample time to attend to the restoring of the drop and the only possible advantage in the combined drop-and-jack for this class of work is that it prevents the operator from forgetting to restore the drops. However, she is not likely to do this with the night-alarm circuit in operation, since the buzzer or bell would continue to ring as long as the drop was down. [Illustration: Fig. 294. Upright Magneto Switchboard] [Illustration: Fig. 295. Upright Magneto Switchboard--Rear View] _Upright Type Switchboard._ By far the most common type of magneto switchboard is the so-called upright type, wherein the drops and jacks are mounted on the face of upright panels rising from a horizontal shelf, which shelf contains the plugs, the keys, and any other apparatus which the operator must manipulate. Front and rear views of such a switchboard, as manufactured by the Kellogg Company, are shown in Figs. 294 and 295. This particular board is provided with fifty combined drops and jacks and, therefore, equipped for fifty subscribers' lines. The drops and jacks are mounted in strips of five, and arranged in two panels. The clearing-out drops, of which there are ten, are arranged at the bottom of the two panels in a single row and may be seen immediately above the switchboard plugs. There are ten pairs of cords and plugs with their associated ringing and listening keys, the plugs being mounted on the rear portion of the shelf, while the ringing and listening keys are mounted on the hinged portion of the shelf in front of the plugs. [Illustration: Fig. 296. Details of Drop, Jack, Plug, and Key Arrangement] [Illustration: Fig. 297. Cross-Section of Upright Switchboard] A better idea of the arrangement of drops, jacks, plugs, and keys may be had from an illustration of a Dean magneto switchboard shown in Fig. 296. The clearing-out drops and the arrangement of the plugs and keys are clearly shown. The portion of the switchboard on which the plugs are mounted is always immovable, the plugs being provided with seats through which holes are bored of sufficient size to permit the switchboard cord to pass beneath the shelf. When one of these plugs is raised, the cord is pulled up through this hole thus allowing the plug to be placed in any of the jacks. The key arrangement shown in this particular cut is instructive. It will be noticed that the right-hand five pairs of plugs are provided with ordinary ringing and listening keys, while the left-hand five are provided with party-line ringing keys and listening keys. The listening key in each case is the one in the rear and is alike for all of the cord pairs. The right-hand five ringing keys are so arranged that pressing the lever to the rear will ring on the answering cord, while pressing it toward the front will cause ringing current to flow on the calling plug. In the left-hand five pairs of cords shown in this cut, the pressure of any one of the keys causes a ringing current of a certain frequency to flow on the calling cord, this frequency depending upon which one of the keys is pressed. [Illustration: Fig. 298. Cord Weight] An excellent idea of the grouping of the various pieces of apparatus in a complete simple magneto switchboard may be had from Fig. 297. While the arrangement here shown is applicable particularly to the apparatus of the Dean Electric Company, the structure indicated is none-the-less generally instructive, since it represents good practice in this respect. In this drawing the stationary plug shelf with the plug seat is clearly shown and also the hinged key shelf. The hinge of the key shelf is an important feature and is universally found in all switchboards of this general type. The key shelf may be raised and thus expose all of the wiring leading to the keys, as well as the various contacts of the keys themselves, to inspection. [Illustration: Fig. 299. Magneto Switchboard, Target Signals] As will be seen, the switchboard cords leading from the plugs extend down to a point near the bottom of the cabinet where they pass through pulley weights and then up to a stationary cord rack. On this cord rack are provided terminals for the various conductors in the cord, and it is at this point that the cord conductors join the other wires leading to the other portions of the apparatus as required. A good form of cord weight is shown in Fig. 298; and obviously the function of these weights is to keep the cords taut at all times and to prevent their tangling. [Illustration: Fig. 300. Rear View of Target Signal, Magneto Switchboard] The drawing, Fig. 297, also gives a good idea of the method of mounting the hand generator that is ordinarily employed with such magneto switchboards. The shaft of the generator is merely continued out to the front of the key shelf where the usual crank is provided, by means of which the operator is able to generate the necessary ringing current. Beside the hand generator at each operator's position, it is quite common in magneto boards, of other than the smallest sizes, to employ some form of ringing generator, either a power-driven generator or a pole changer driven by battery current for furnishing ringing current without effort on the part of the operator. [Illustration: Fig. 301. Dean Two-Position Switchboard] Switchboards as shown in Figs. 294 and 295, are called single-position switchboards because they afford room for a single operator. Ordinarily for this class of work a single operator may handle from one to two hundred lines, although of course this depends on the amount of traffic on the line, and this, in turn, depends on the character of the subscribers served, and also on the average number of stations on a line. Another single-position switchboard is shown in Figs. 299 and 300, being a front and rear view of the simple magneto switchboard of the Western Electric Company, which is provided with the target signals of that company rather than the usual form of drop. Where a switchboard must accommodate more lines than can be handled by a single operator, the cabinet is made wider so as to afford room for more than one operator to be seated before it. Sometimes this is accomplished by building the cabinet wider, or by putting two such switchboard sections as are shown in Figs. 294 or 299 side by side. A two-position switchboard section is shown in front and rear views in Figs. 301 and 302. [Illustration: Fig. 302. Rear View of Dean Two-Position Switchboard] _Sectional Switchboards._ The problem of providing for growth in a switchboard is very much the same as that which confronts one in buying a bookcase for his library. The Western Electric Company has met this problem, for very small rural exchanges, in much the same way that the sectional bookcase manufacturers have provided for the possible increase in bookcase capacity. Like the sectional bookcase, this sectional switchboard may start with the smallest of equipment--a single sectional unit--and may be added to vertically as the requirements increase, the original equipment being usable in its more extended surroundings. [Illustration: Fig. 303. Sectional Switchboard--Wall Type] This line of switchboards is illustrated in Figs. 303 to 306. The beginning may be made with either a wall type or an upright type of switchboard, the former being mounted on brackets secured to the wall, and the latter on a table. A good idea of the wall type is shown in Fig. 303. Three different kinds of sectional units are involved in this: first, the unit which includes the cords, plugs, clearing-out drops, listening jacks, operator's telephone set and generator; second, the unit containing the line equipment, including a strip of ten magneto line signals and their corresponding jacks; third, the finishing top, which includes no equipment except the support for the operator's talking apparatus. [Illustration: Fig. 301. Sectional Switchboard--Wall Type] The first of the units in Fig. 303 forms the foundation on which the others are built. Two of the line-equipment units are shown; these provide for a total of twenty lines. The top rests on the upper line-equipment unit, and when it becomes necessary to add one or more line-equipment units as the switchboard grows, this top is merely taken off, the other line-equipment units put in place on top of those already existing, and the top replaced. The wall type of sectional switchboard is so arranged that the entire structure may be swung out from the wall, as indicated in Fig. 304, exposing all of the apparatus and wiring for inspection. Each of the sectional units is provided with a separate door, as indicated, so that the rear door equipment is added to automatically as the sections are added. In the embodiment of the sectional switchboard idea shown in these two figures just referred to, no ringing and listening keys are provided, but the operator's telephone and generator terminate in a special plug--the left-hand one shown in Fig. 303--and when the operator desires to converse with the connected subscribers, she does so by inserting the operator's plug into one of the jacks immediately below the clearing-out drop corresponding to the pair of plugs used in making the connection. The arrangement in this case is exactly the same in principle as that described in Fig. 292. The operator's generator is so arranged in connection with this left-hand operator's plug that the turning of the generator crank automatically switches the operator's telephone set off and switches the generator on, just the same as a switch hook may do in a subscriber's series telephone. [Illustration: Fig. 305. Sectional Switchboard--Table Type] [Illustration: Fig. 306. Sectional Switchboard--Table Type] The upright type of sectional switchboard is shown in Figs. 305 and 306, which need no explanation in view of the foregoing, except to say that, in the particular instrument illustrated, ringing and listening keys are provided instead of the jack-and-plug arrangement of the wall type. In this case also, the top section carries an arm for supporting a swinging transmitter instead of the hook support for the combined transmitter and receiver. REVIEW QUESTIONS [Blank Page] REVIEW QUESTIONS ON THE SUBJECT OF TELEPHONY PAGES 11--62 * * * * * 1. When was the telephone invented and by whom? 2. State the velocity of sound in air. Is it higher in air than in a denser medium? 3. State and define the characteristics of sound. 4. Make sketch of Bell's original magneto telephone without permanent magnets. 5. Describe and sketch Hughes' microphone. 6. Which is, at present, the best material for varying the resistance in transmitters? 7. Give the fundamental differences between the magneto transmitter and the carbon transmitter. 8. What is the function of the induction coil in the telephone circuit? 9. Describe and sketch the different kinds of visible signals. 10. What should be the diameter of hard drawn copper wire in order to allow economical spacing of poles? 11. State the four principal properties of a telephone line. 12. If in testing a line the capacity is changed what are the results found on the receiver and transmitter end? 13. Why is paper used as an insulator of telephone cables? 14. How does a conductor behave in connection with direct current and how with alternating current? 15. What influence has inductance on the telephone? 16. Define impedance and give the formula for it. 17. What is the usual specification for insulation of resistance in telephone cables? 18. If 750 feet of cable have an insulation resistance of 9,135 megohms, how great is the insulation resistance for 7 miles and 1,744 feet of cable? 19. What is the practical limiting conversation distance for No. 10 B. and S. wire? 20. Describe Professor Pupin's method of inserting inductance into the telephone line. 21. What does _mho_ denote? 22. Why are Pupin's coils not so successful on open wires? 23. What is a repeater? 24. Define _reactive interference_. 25. State the frequencies of the pitches of the human voice. 26. What is the office of a diaphragm in a telephone apparatus? 27. What transmitter material has greatly increased the ranges of speech? 28. Describe the different methods of measurements of telephone circuits. 29. What are the two kinds of _electric calls_? 30. How many conductors has a telephone line? 31. Give formula for capacity reactance and the meaning of the symbols. 32. Which American cities are joined by underground lines at present? 33. State the two practical ways of improving telephone transmission. REVIEW QUESTIONS ON THE SUBJECT OF TELEPHONY PAGES 63--141 * * * * * 1. On what general principle are most of the telephone transmitters of today constructed? 2. Make sketch of the new Western Electric transmitter and describe its working. 3. Make sketch and describe the Kellogg transmitter. 4. What troubles were encountered in the earlier forms of granular carbon transmitters and how were they overcome? 5. What limits the current-carrying capacity of the transmitter? How may this capacity be increased? 6. State in what kind of transmitters a maximum degree of sensitiveness is desirable. 7. Show the conventional symbols for transmitters. 8. Describe a telephone receiver. 9. Sketch a Western Electric receiver and point out its deficiencies. 10. Make a diagram of the Kellogg receiver. 11. Describe the direct-current receiver of the Automatic Electric Company. 12. Describe and sketch the Dean receiver. 13. Show the conventional symbols of a receiver. 14. Describe exactly how, in a cell composed of a tin and a silver plate with dilute sulphuric acid as electrolyte, the current inside and outside of the cell will flow. 15. Describe the phenomenon of polarization. 16. What is _local action_ of a cell? How may it be prevented? 17. Into how many classes may cells be divided? Which class is most used in telephony? 18. Describe the LeClanché cell. 19. Sketch and describe an excellent form of dry cell. 20. Show the conventional symbols for batteries. 21. Sketch and describe the generator shunt switch and the generator cut-in switch. 22. How may a pulsating current be derived from a magneto generator? 23. Show conventional symbols for magneto generators. 24. Sketch and describe the Western Electric polarized bell. 25. Give conventional ringer symbols. 26. What is the purpose of the hook switch? 27. Make sketch and give description of Kellogg's long lever hook switch. 28. Describe and sketch the Western Electric short lever hook switch. 29. Point out the principal difference between the desk stand hook switches of the Western Electric Company and of the Kellogg Switchboard and Supply Company. 30. Give conventional symbols of hook switches. REVIEW QUESTIONS ON THE SUBJECT OF TELEPHONY PAGES 143--225 * * * * * 1. Describe an electromagnet and its function in telephony. 2. Sketch an iron-clad electromagnet. 3. What is a differential electromagnet? Sketch and describe one type. 4. State the desirable characteristics of good enamel insulation for magnet wire. 5. If you have a coil of No. 23 double cotton B. and S. wire of 115 ohms resistance and you have to rewind it for 1,070 ohms resistance with double cotton wire, what number of wire would you take? Show calculation. NOTE. No. 23 d. c wire has res. 1.772 ohms per cubic inch; for the core, 115 ohms. There are required in the coil 1,070 ohms, that is, 9.3 times as much. 1.772 x 9.3 = 16.47 ohms, which must be the resistance per cu. in. This resistance gives, according to Table IV, No. 29 wire. 6. What is an impedance coil? State how it differs from an electromagnet coil. 7. Describe the different kinds of impedance coils. 8. Give symbol of impedance coil. 9. What are the principal parts of an induction coil? 10. What is the function of an induction coil in telephony? 11. What is a repeating coil and how does it differ from an induction coil? 12. Give conventional symbols of induction coils and repeating coils. 13. Enumerate the different types of non-inductive resistance devices and give a short description of each. 14. Define condenser. 15. What is the meaning of the word _dielectrics_? 16. State what you understand by the specific inductive capacity of a dielectric. 17. Upon what factors does the capacity of a condenser depend? 18. What is the usual capacity of condensers in telephone practice? 19. Give conventional condenser symbols. 20. By what two methods may the current be supplied to a telephone transmitter? 21. Make sketch of local-battery stations with metallic circuit. 22. Sketch common-battery circuit in series with two lines. 23. State the objections against the preceding arrangement. 24. Make sketch of the standard arrangement of the Western Electric Company in bridging the common battery with repeating coils. 25. Sketch the arrangement of bridging the battery with impedance coils and state the purpose of the coils. 26. Make diagram of a common-source current supply for many lines with repeating coils and point out the travel of the voice currents. 27. Name the different parts which comprise a telephone set. 28. What is a magneto telephone? 29. Make diagram of the circuit of a series magneto set with receiver on the hook and explain how the different currents are flowing. 30. Show diagram of the Stromberg-Carlson magneto desk telephone circuit and describe its working. 31. Give sketch of the Stromberg-Carlson common-battery wall set circuit. 32. Describe briefly the microtelephone set. 33. Make sketch of the Monarch common-battery wall set. REVIEW QUESTIONS ON THE SUBJECT OF TELEPHONY PAGES 227--286 * * * * * 1. What is a party line? 2. What is usually understood by private lines? 3. What problem is there to overcome in connection with party lines? 4. State the two general classes of party-line systems. 5. Point out the defects of the series system. 6. Make sketch of a metallic bridging line and show the circuit for the voice currents. 7. What is a signal code? 8. Give classification of selective party-line systems with short definitions. 9. Describe the principle of selection by polarity and make sketch illustrating this principle. 10. Make diagram of the circuit of a four-party station with relay. 11. Describe the process of tuning in the harmonic system. 12. What is the difference between the under-tune and in-tune systems? 13. Sketch circuit of Kellogg's harmonic system. 14. Illustrate the principle of a broken-line system by a sketch. 15. In what particulars does the party-line system in rural districts differ from that within urban limits? 16. Describe and sketch Pool's lock-out system. 17. Make diagram of the K.B. lock-out system. 18. What is the object of the ratchet in this system? 19. Make diagram of simplified circuits of Roberts system. 20. Sketch and describe Roberts latching key and connections. 21. Sketch circuits of bridging station for non-selective party line. 22. How would you arrange the signal code for six stations on a non-selective party line? 23. What is the limit of number of stations on a non-selective party line under ordinary circumstances? 24. State the objections against the party polarity system as shown in Fig. 172. 25. What are the advantages of the harmonic party-line system? 26. To how many frequencies is the harmonic system usually limited? 27. What can you say about the commercial success of the step-by-step method? 28. State the principles of a lock-out party line. 29. For what purpose is a condenser placed in the receiver circuit of each station in the K.B. lock-out system? 30. How are the selecting relays in Roberts line restored to their normal position after a conversation is finished? 31. What are the objections against the Roberts system? REVIEW QUESTIONS ON THE SUBJECT OF TELEPHONY PAGES 287--315 * * * * * 1. What are electrical hazards? 2. When is the lightning hazard least? 3. What actions can electricity produce? Which involves the greater hazard to the value of property? 4. When is a piece of apparatus called "self-protecting"? 5. Why must a protector for telephone apparatus work more quickly for a large current than for a small one? 6. State the general problem which heating hazards present with relation to telephone apparatus. 7. What is the most nearly universal electrical hazard? 8. Sketch and describe the saw-tooth lightning arrester. 9. Make diagram of the carbon-block arrester and state its advantages. 10. Describe a vacuum arrester. 11. Explain the reason for placing an impedance in connection with the lightning arrester. 12. What is the purpose of the globule of low-melting alloy in the Western Electric Company's arrester? 13. Why are not fuses good lightning arresters? 14. What is the proper function of a fuse? 15. Make sketch of a mica slip fuse. 16. Define _sneak currents_. 17. Make a diagram of a sneak-current arrester and describe its principles and working. 18. Describe a heat coil. 19. Sketch a complete line protection. 20. Where is the proper position of the fuse? 21. Which wires are considered exposed and which unexposed? 22. Why is it not necessary to install sneak-current arresters in central-battery subscribers' stations? 23. Sketch and describe the action of a combined sneak-current and air-gap arrester, as widely used by Bell companies. 24. Describe the self-soldering heat-coil arrester. 25. What is the purpose of ribbon fuses? 26. What is a drainage coil? REVIEW QUESTIONS ON THE SUBJECT OF TELEPHONY PAGES 317--386 * * * * * 1. What is a central office? 2. What are (_a_) subscriber's lines? (_b_) Trunk lines? (_c_) Toll lines? 3. For what purpose is the switchboard? 4. Give short descriptions of the different classes of switchboards. 5. How are manual switchboards subdivided? Describe briefly the different types. 6. Define A and B boards. 7. What is a call circuit? 8. What kind of calls are handled on a toll switchboard? 9. Give drop symbol and describe its principles. 10. What is a jack? 11. Make a sketch of a plug inserted into a jack. 12. Give jack and plug symbols. 13. What are ringing and listening keys? 14. Show symbols for ringing and listening keys. 15. State the parts of which a cord equipment consists. 16. Show step by step the various operations of a telephone system wherein the lines center in a magneto switchboard. Make all the necessary diagrams and give brief descriptions to show that you understand each operation. 17. On what principle does a drop with night-alarm contact operate? 18. What is the advantage of associating jacks and drops? 19. Describe the mechanical restoration as employed in the Miller drop and jack. 20. Describe the electrical restoration of drop shutters as manufactured by the Western Electric Company. 21. What complications arise in ringing of party lines and how are they overcome? 22. Give diagram of the complete circuit of a simple magneto switchboard. 23. Sketch night-alarm circuit with relay. 24. What is a convertible cord circuit? 25. State what disadvantages may be encountered under certain conditions with a bridging drop-cord circuit. 26. Are lamps in cord circuits to be advocated on magneto switchboards? 27. What is the function of the cabinet? 28. Give cross-section of upright switchboard as used in the magneto system. 29. What is the purpose of a sectional switchboard? 30. Give a short description of the essential parts of a sectional switchboard. INDEX INDEX _The page numbers of this volume will be found at the bottom of the pages; the numbers at the top refer only to the section._ A Acousticon transmitter Acoustics characteristics of sound loudness pitch timbre human ear human voice propagation of sound Air-gap vs. fuse arresters Amalgamated zincs Arrester separators Audible signals magneto bell telegraph sounder telephone receiver vibrating bell Automatic Electric Company direct-current receiver transmitter Automatic shunt B Bar electromagnet Battery bell Battery symbols Blake single electrode Brazed bell Broken-back ringer Broken-line method of selective signaling C Capacity reactance Carbon adaptability limitations preparation of superiority Carbon air-gap arrester Carbon-block arrester Carrying capacity of transmitter Central-office protectors Characteristics of sound loudness pitch timbre Chloride of silver cell Closed-circuit cells Closed-circuit impedance coil Common-battery telephone sets Condensers capacity charge conventional symbols definition of dielectric dielectric materials functions means for assorting current sizes theory Conductivity of conductors Conductors, conductivity of Conventional symbols Cook air-gap arrester arrester arrester for magneto stations Crowfoot cell Current supply to transmitters common battery advantages bell substation arrangement bridging battery with impedance coils bridging battery with repeating coil current supply from distant point current supply over limbs of line in parallel Dean substation arrangement double battery with impedance coil Kellogg substation arrangement North Electric Company system series battery series substation arrangement Stromberg-Carlson system supply many lines from common source repeating coil retardation coil local battery D Dean drop and jack receiver wall telephone hook Desk stand hooks Kellogg Western Electric Dielectric Dielectric materials dry paper mica Differential electromagnet Direct-current receiver Drainage coils E Electric lamp signal Electrical hazards Electrical reproduction of speech carbon conversion from sound waves to vibration of diaphragm conversion from vibration to voice currents conversion from voice currents to vibration cycle of conversion detrimental effects of capacity early conceptions electrostatic telephone induction coil limitations of magneto transmitter loose contact principle magneto telephone measurements of telephone currents variation of electrical pressure variation of resistance Electrical signals audible magneto-bell telegraph sounder telephone receiver vibrating bell visible electric lamp signal electromagnetic signal Electrodes arrangement of carbon preparation multiple single Electrolysis Electromagnetic method of measuring telephone currents Electromagnetic signal Electromagnets and inductive coils conventional symbols differential electromagnet direction of armature motion direction of lines of force electromagnets low-resistance circuits horseshoe form iron-clad form special horseshoe form impedance coils kind of iron number of turns types closed-circuit open-circuit toroidal induction coil current and voltage ratios design functions use and advantage magnet wire enamel silk and cotton insulation space utilization wire gauges magnetic flux magnetization curves magnetizing force mechanical details permeability reluctance repeating coil winding methods winding calculations winding data winding terminals Electrostatic capacity unit of Electrostatic telephone Enamel F Five-bar generator Fuller cell G Galvani Generator armature Generator cut-in switch Generator shunt switch Generator symbols Granular carbon Gravity cell H Hand receivers Harmonic method of selective signaling advantages circuits in-tune system limitations principles tuning under-tune system Head receivers Heat coil Holtzer-Cabot arrester Hook switch automatic operation contact material design desk stand hooks Kellogg Western Electric purpose symbols wall telephone hooks Dean Kellogg Western Electric Horseshoe electromagnet Human ear Human voice I Impedance coils kind of iron number of turns symbols of types closed-circuit open-circuit toroidal Inductance vs. capacity Induction coil current and voltage ratios design functions use and advantage Inductive neutrality Inductive reactance Insulation of conductors Introduction to telephony Iron-clad electromagnet Iron wire ballast K Kellogg air-gap arrester desk stand hook drop and jack receiver ringer transmitter wall telephone hook L Lalande cell Lamp filament Le Clanché cell Lenz law Line signals Lines of force, direction of Loading coils Lock-out party-line systems broken-line method operation Poole system step-by-step system Loudness of sound Low-reluctance circuits horseshoe form iron-clad form M Magnetic flux Magnetization curves Magnetizing force Magneto bell Magneto operator Magneto signaling apparatus armature automatic shunt battery bell generator symbols magneto bell magneto generator method of signaling polarized ringer pulsating current ringer symbols theory Magneto switchboard automatic restoration mechanical Dean type Kellogg type Monarch type Western Electric type circuits of complete switchboard code signaling commercial types of drops and jacks early drops jack mounting manual vs. automatic restoration methods of associating night alarm tubular drops component parts jacks and plugs keys line and cord equipments line signal operators' equipment cord-circuit considerations double clearing-out type lamp-signal type non-ring through type series drop type simple bridging drop type definitions electrical restoration grounded and metallic-circuit lines mode of operation night-alarm circuits operation in detail clearing out essentials of operation normal condition of line operator answering operator calling subscriber calling subscribers conversing operator's telephone equipment cut-in jack ringing and listening keys horizontal spring type party-line ringing keys self-indicating keys vertical spring type switchboard assembly functions of cabinet sectional switchboards upright type of switchboard wall type switchboard switchboard cords concentric conductors parallel tinsel conductors steel spiral conductors switchboard plugs Magneto telephone Magneto telephone sets Mica card resistance Mica slip fuse Microtelephone set Monarch drop and jack Monarch receiver Monarch transmitter Multiple electrode Mutual induction N Non-inductive resistance devices inductive neutrality provisions against heating temperature coefficient types differentially-wound unit iron wire ballast lamp filament mica card unit Non-selective party-line systems bridging limitations series signal code O Open-circuit cells Open-circuit impedance coil Operator's receiver P Packing of transmitters Permeability Pitch Doppler's principle vibration of diaphragms Polarity method of selective signaling Polarization of cells Polarized ringer brazed bell Kellogg Western Electric Poole lock-out system Primary cells conventional symbol series and multiple connections simple voltaic types of closed-circuit Fuller gravity Lalande prevention of creeping setting up open-circuit Le Clanché standard chloride of silver Propagation of sound Protective means against high potentials air-gap arrester advantages of carbon commercial types continuous arcs discharge across gaps dust between carbons introduction of impedance metallic electrodes vacuum arresters against sneak currents heat coil sneak-current arresters against strong currents fuses enclosed mica proper functions central-office protectors self-soldering heat coils sneak-current and air-gap arrester city exchange requirements complete line protection electrolysis subscribers' station protectors ribbon fuses Pulsating-current commutator R Receivers Dean direct-current early Kellogg modern Monarch operator's single-pole symbols Western Electric Reluctance Repeating coil Ribbon fuses Ringer symbols Ringing and listening key Robert's latching relay Robert's self-cleansing arrester Rolled condenser S Saw-tooth arrester Selective party-line systems broken-line method classification broken-line systems harmonic systems polarity systems step-by-step systems harmonic method polarity method step-by-step method Self-induction Signal code Signaling, method of Silk and cotton insulation Single electrode Single-pole receiver Sneak-current arresters Solid-back transmitter Sound characteristics of loudness pitch timbre Standard cell Step-by-step lock-out system Step-by-step method of selective signaling Subscribers' station protectors Switchboard cords Switchboard plugs Switchboard transmitter Symbols battery condenser generator hook switch impedance coil induction coil receiver repeating coil ringer ringing and listening key transmitter T Table condenser data copper wire German silver wire--18 per cent German silver wire--30 per cent metals, behavior of, in different electrolysis signal code specific inductive capacities temperature coefficients transmission distances, limiting winding data for insulating wires Tandem differential electromagnet Telegraph sounder Telephone currents, measurements of electromagnetic method thermal method Telephone exchange, features of districts subscribers' lines switchboards toll lines trunk lines Telephone lines conductivity of conductors electrostatic capacity inductance of circuit inductance vs. capacity insulation of conductors transmission Telephone sets classification of common-battery telephone magneto telephone wall and desk telephones common-battery desk hotel wall magneto circuits of bridging series desk wall Temperature coefficients Thermal method of measuring telephone currents Timbre Toroidal impedance coil Toroidal repeating coil Transmission, ways of improving Transmitters acousticon Automatic Electric Company carrying capacity conventional diagram electrode arrangement of multiple single granular carbon Kellogg materials Monarch packing sensitiveness switchboard symbols variable resistance Western Electric solid-back U Under-tuned ringer V Vacuum arrester Variable resistance Vibrating bell Visible signals electric lamp electromagnetic Volta Voltaic cell amalgamated zincs difference of potential local action polarization theory W Wall telephone hooks Dean Kellogg Western Electric Western Electric air-gap arrester desk stand hook drop and jack receiver ringer solid-back transmitter station arrester wall telephone hook White transmitter Wire gauges 
33437	----	[Illustration: THOMAS A. EDISON Pioneer Electrical Investigator and Inventor of Numerous Telegraph, Telephone, Lighting, and Other Electrical Devices.] Cyclopedia of Telephony and Telegraphy _A General Reference Work on_ TELEPHONY, SUBSTATIONS, PARTY LINE SYSTEMS, PROTECTION, MANUAL SWITCHBOARDS, AUTOMATIC SYSTEMS, POWER PLANTS, SPECIAL SERVICE FEATURES, CONSTRUCTION, ENGINEERING, OPERATION, MAINTENANCE, TELEGRAPHY, WIRELESS TELEGRAPHY AND TELEPHONY, ETC. _Prepared by a Corps of_ TELEPHONE AND TELEGRAPH EXPERTS, AND ELECTRICAL ENGINEERS OF THE HIGHEST PROFESSIONAL STANDING _Illustrated with over Two Thousand Engravings_ FOUR VOLUMES CHICAGO AMERICAN SCHOOL OF CORRESPONDENCE 1919 COPYRIGHT, 1911, 1912, BY AMERICAN SCHOOL OF CORRESPONDENCE COPYRIGHT, 1911, 1912 BY AMERICAN TECHNICAL SOCIETY Entered at Stationers' Hall, London All Rights Reserved Authors and Collaborators * * * * * KEMPSTER B. MILLER, M.E. Consulting Engineer and Telephone Expert Of the Firm of McMeen and Miller, Electrical Engineers and Patent Experts, Chicago American Institute of Electrical Engineers Western Society of Engineers * * * * * GEORGE W. PATTERSON, S.B., Ph.D. Head, Department of Electrical Engineering, University of Michigan * * * * * CHARLES THOM Chief of Quadruplex Department, Western Union Main Office, New York City * * * * * ROBERT ANDREWS MILLIKAN, Ph.D. Associate Professor of Physics, University of Chicago Member, Executive Council, American Physical Society * * * * * SAMUEL G. McMEEN Consulting Engineer and Telephone Expert Of the Firm of McMeen and Miller, Electrical Engineers and Patent Experts, Chicago American Institute of Electrical Engineers Western Society of Engineers * * * * * LAWRENCE K. SAGER, S.B., M.P.L. Patent Attorney and Electrical Expert Formerly Assistant Examiner, U.S. Patent Office * * * * * GLENN M. HOBBS, Ph.D. Secretary, American School of Correspondence Formerly Instructor in Physics, University of Chicago American Physical Society * * * * * CHARLES G. ASHLEY Electrical Engineer and Expert in Wireless Telegraphy and Telephony * * * * * A. FREDERICK COLLINS Editor, _Collins Wireless Bulletin_ Author of "Wireless Telegraphy, Its History, Theory, and Practice" * * * * * FRANCIS B. CROCKER, E.M., Ph.D. Head, Department of Electrical Engineering, Columbia University Past-President, American Institute of Electrical Engineers * * * * * MORTON ARENDT, E.E. Instructor in Electrical Engineering, Columbia University, New York * * * * * EDWARD B. WAITE Head, Instruction Department, American School of Correspondence American Society of Mechanical Engineers Western Society of Engineers * * * * * DAVID P. MORETON, B.S., E.E. Associate Professor of Electrical Engineering, Armour Institute of Technology American Institute of Electrical Engineers * * * * * LEIGH S. KEITH, B.S. Managing Engineer with McMeen and Miller, Electrical Engineers and Patent Experts Chicago Associate Member, American Institute of Electrical Engineers * * * * * JESSIE M. SHEPHERD, A.B. Associate Editor, Textbook Department, American School of Correspondence * * * * * ERNEST L. WALLACE, B.S. Assistant Examiner, United States Patent Office, Washington, D. C. * * * * * GEORGE R. METCALFE, M.E. Editor, _American Institute of Electrical Engineers_ Formerly Head of Publication Department, Westinghouse Elec. & Mfg. Co. * * * * * J. P. SCHROETER Graduate, Munich Technical School Instructor in Electrical Engineering, American School of Correspondence * * * * * JAMES DIXON, E.E. American Institute of Electrical Engineers * * * * * HARRIS C. TROW, S.B., _Managing Editor_ Editor-in-Chief, Textbook Department, American School of Correspondence Authorities Consulted The editors have freely consulted the standard technical literature of America and Europe in the preparation of these volumes. They desire to express their indebtedness particularly to the following eminent authorities, whose well-known works should be in the library of every telephone and telegraph engineer. Grateful acknowledgment is here made also for the invaluable co-operation of the foremost engineering firms and manufacturers in making these volumes thoroughly representative of the very best and latest practice in the transmission of intelligence, also for the valuable drawings, data, suggestions, criticisms, and other courtesies. * * * * * ARTHUR E. KENNELY, D.Sc. Professor of Electrical Engineering, Harvard University. Joint Author of "The Electric Telephone," "The Electric Telegraph," "Alternating Currents," "Arc Lighting," "Electric Heating," "Electric Motors," "Electric Railways," "Incandescent Lighting," etc. * * * * * HENRY SMITH CARHART, A.M., LL.D. Professor of Physics and Director of the Physical Laboratory, University of Michigan. Author of "Primary Batteries," "Elements of Physics," "University Physics," "Electrical Measurements," "High School Physics," etc. * * * * * FRANCIS B. CROCKER, M.E., Ph.D. Head of Department of Electrical Engineering, Columbia University, New York; Past-President, American Institute of Electrical Engineers. Author of "Electric Lighting;" Joint Author of "Management of Electrical Machinery." * * * * * HORATIO A. FOSTER Consulting Engineer; Member of American Institute of Electrical Engineers; Member of American Society of Mechanical Engineers. Author of "Electrical Engineer's Pocket-Book." * * * * * WILLIAM S. FRANKLIN, M.S., D.Sc. Professor of Physics, Lehigh University. Joint Author of "The Elements of Electrical Engineering," "The Elements of Alternating Currents." * * * * * LAMAR LYNDON, B.E., M.E. Consulting Electrical Engineer; Associate Member of American Institute of Electrical Engineers; Member, American Electro-Chemical Society. Author of "Storage Battery Engineering." * * * * * ROBERT ANDREWS MILLIKAN, Ph.D. Professor of Physics, University of Chicago. Joint Author of "A First Course in Physics," "Electricity, Sound and Light," etc. * * * * * KEMPSTER B. MILLER, M.E. Consulting Engineer and Telephone Expert; of the Firm of McMeen and Miller, Electrical Engineers and Patent Experts, Chicago. Author of "American Telephone Practice." * * * * * WILLIAM H. PREECE Chief of the British Postal Telegraph. Joint Author of "Telegraphy," "A Manual of Telephony," etc. * * * * * LOUIS BELL, Ph.D. Consulting Electrical Engineer; Lecturer on Power Transmission, Massachusetts Institute of Technology. Author of "Electric Power Transmission," "Power Distribution for Electric Railways," "The Art of Illumination," "Wireless Telephony," etc. * * * * * OLIVER HEAVISIDE, F.R.S. Author of "Electro-Magnetic Theory," "Electrical Papers," etc. * * * * * SILVANUS P. THOMPSON, D.Sc., B.A., F.R.S., F.R.A.S. Principal and Professor of Physics in the City and Guilds of London Technical College. Author of "Electricity and Magnetism," "Dynamo-Electric Machinery," "Polyphase Electric Currents and Alternate-Current Motors," "The Electromagnet," etc. * * * * * ANDREW GRAY, M.A., F.R.S.E. Author of "Absolute Measurements in Electricity and Magnetism." * * * * * ALBERT CUSHING CREHORE, A.B., Ph.D. Electrical Engineer; Assistant Professor of Physics, Dartmouth College; Formerly Instructor in Physics, Cornell University. Author of "Synchronous and Other Multiple Telegraphs;" Joint Author of "Alternating Currents." * * * * * J. J. THOMSON, D.Sc., LL.D., Ph.D., F.R.S. Fellow of Trinity College, Cambridge University; Cavendish Professor of Experimental Physics, Cambridge University. Author of "The Conduction of Electricity through Gases," "Electricity and Matter." * * * * * FREDERICK BEDELL, Ph.D. Professor of Applied Electricity, Cornell University. Author of "The Principles of the Transformer;" Joint Author of "Alternating Currents." * * * * * DUGALD C. JACKSON, C.E. Head of Department of Electrical Engineering, Massachusetts Institute of Technology; Member, American Institute of Electrical Engineers, etc. Author of "A Textbook on Electromagnetism and the Construction of Dynamos;" Joint Author of "Alternating Currents and Alternating-Current Machinery." * * * * * MICHAEL IDVORSKY PUPIN, A.B., Sc.D., Ph.D. Professor of Electro-Mechanics, Columbia University, New York. Author of "Propagation of Long Electric Waves," and "Wave-Transmission over Non-Uniform Cables and Long-Distance Air Lines." * * * * * FRANK BALDWIN JEWETT, A.B., Ph.D. Transmission and Protection Engineer, with American Telephone & Telegraph Co. Author of "Modern Telephone Cable," "Effect of Pressure on Insulation Resistance." * * * * * ARTHUR CROTCH Formerly Lecturer on Telegraphy and Telephony at the Municipal Technical Schools, Norwich, Eng. Author of "Telegraphy and Telephony." * * * * * JAMES ERSKINE-MURRAY, D.Sc. Fellow of the Royal Society of Edinburgh; Member of the Institution of Electrical Engineers. Author of "A Handbook of Wireless Telegraphy." * * * * * A. H. McMILLAN, A.B., LL.B. Author of "Telephone Law, A Manual on the Organization and Operation of Telephone Companies." * * * * * WILLIAM ESTY, S.B., M.A. Head of Department of Electrical Engineering, Lehigh University. Joint Author of "The Elements of Electrical Engineering." * * * * * GEORGE W. WILDER, Ph.D. Formerly Professor of Telephone Engineering, Armour Institute of Technology. Author of "Telephone Principles and Practice," "Simultaneous Telegraphy and Telephony," etc. * * * * * WILLIAM L. HOOPER, Ph.D. Head of Department of Electrical Engineering, Tufts College. Joint Author of "Electrical Problems for Engineering Students." * * * * * DAVID S. HULFISH Technical Editor, _The Nickelodeon_; Telephone and Motion-Picture Expert; Solicitor of Patents. Author of "How to Read Telephone Circuit Diagrams." * * * * * J. A. FLEMING, M.A., D.Sc. (Lond.), F.R.S. Professor of Electrical Engineering in University College, London; Late Fellow and Scholar of St. John's College, Cambridge; Fellow of University College, London. Author of "The Alternate-Current Transformer," "Radiotelegraphy and Radiotelephony," "Principles of Electric Wave Telegraphy," "Cantor Lectures on Electrical Oscillations and Electric Waves," "Hertzian Wave Wireless Telegraphy," etc. * * * * * F. A. C. PERRINE, A.M., D.Sc. Consulting Engineer; Formerly President, Stanley Electric Manufacturing Company; Formerly Professor of Electrical Engineering, Leland Stanford, Jr. University. Author of "Conductors for Electrical Distribution." * * * * * A. FREDERICK COLLINS Editor, _College Wireless Bulletin_. Author of "Wireless Telegraphy, Its History, Theory and Practice," "Manual of Wireless Telegraphy," "Design and Construction of Induction Coils," etc. * * * * * SCHUYLER S. WHEELER, D.Sc. President, Crocker-Wheeler Co.; Past-President, American Institute of Electrical Engineers. Joint Author of "Management of Electrical Machinery." * * * * * CHARLES PROTEUS STEINMETZ Consulting Engineer, with the General Electric Co.; Professor of Electrical Engineering, Union College. Author of "The Theory and Calculation of Alternating-Current Phenomena," "Theoretical Elements of Electrical Engineering," etc. * * * * * GEORGE W. PATTERSON, S.B., Ph.D. Head of Department of Electrical Engineering, University of Michigan. Joint Author of "Electrical Measurements." * * * * * WILLIAM MAVER, Jr. Ex-Electrician Baltimore and Ohio Telegraph Company; Member of the American Institute of Electrical Engineers. Author of "American Telegraphy and Encyclopedia of the Telegraph," "Wireless Telegraphy." * * * * * JOHN PRICE JACKSON, M.E. Professor of Electrical Engineering, Pennsylvania State College. Joint Author of "Alternating Currents and Alternating-Current Machinery." * * * * * AUGUSTUS TREADWELL, Jr., E.E. Associate Member, American Institute of Electrical Engineers. Author of "The Storage Battery, A Practical Treatise on Secondary Batteries." * * * * * EDWIN J. HOUSTON, Ph.D. Professor of Physics, Franklin Institute, Pennsylvania; Joint Inventor of Thomson-Houston System of Arc Lighting; Electrical Expert and Consulting Engineer. Joint Author of "The Electric Telephone," "The Electric Telegraph," "Alternating Currents," "Arc Lighting," "Electric Heating," "Electric Motors," "Electric Railways," "Incandescent Lighting," etc. * * * * * WILLIAM J. HOPKINS Professor of Physics in the Drexel Institute of Art, Science, and Industry, Philadelphia. Author of "Telephone Lines and their Properties." [Illustration: GROSSE POINT EXCHANGE RACK Detroit Home Telephone Company, Detroit, Mich. _The Dean Electric Co._] [Illustration: LINE SIDE OF LARGE MAIN DISTRIBUTING FRAME] Foreword The present day development of the "talking wire" has annihilated both time and space, and has enabled men thousands of miles apart to get into almost instant communication. The user of the telephone and the telegraph forgets the tremendousness of the feat in the simplicity of its accomplishment; but the man who has made the feat possible knows that its very simplicity is due to the complexity of the principles and appliances involved; and he realizes his need of a practical, working understanding of each principle and its application. The Cyclopedia of Telephony and Telegraphy presents a comprehensive and authoritative treatment of the whole art of the electrical transmission of intelligence. The communication engineer--if so he may be called--requires a knowledge both of the mechanism of his instruments and of the vagaries of the current that makes them talk. He requires as well a knowledge of plants and buildings, of office equipment, of poles and wires and conduits, of office system and time-saving methods, for the transmission of intelligence is a business as well as an art. And to each of these subjects, and to all others pertinent, the Cyclopedia gives proper space and treatment. The sections on Telephony cover the installation, maintenance, and operation of all standard types of telephone systems; they present without prejudice the respective merits of manual and automatic exchanges; and they give special attention to the prevention and handling of operating "troubles." The sections on Telegraphy cover both commercial service and train dispatching. Practical methods of wireless communication--both by telephone and by telegraph--are thoroughly treated. The drawings, diagrams, and photographs incorporated into the Cyclopedia have been prepared especially for this work; and their instructive value is as great as that of the text itself. They have been used to illustrate and illuminate the text, and not as a medium around which to build the text. Both drawings and diagrams have been simplified so far as is compatible with their correctness, with the result that they tell their own story and always in the same language. The Cyclopedia is a compilation of many of the most valuable Instruction Papers of the American School of Correspondence, and the method adopted in its preparation is that which this School has developed and employed so successfully for many years. This method is not an experiment, but has stood the severest of all tests--that of practical use--which has demonstrated it to be the best yet devised for the education of the busy, practical man. In conclusion, grateful acknowledgment is due to the staff of authors and collaborators, without whose hearty co-operation this work would have been impossible. Table of Contents VOLUME II MANUAL SWITCHBOARDS _By K. B. Miller and S. G. McMeen_[A] Page[B] 11 Common-Battery Switchboards--Line Signals--Cord Circuit--Lamps--Mechanical Signals--Relays--Jacks--Switchboard Assembly--Transfer Switchboard--Transfer Lines--Handling Transfers--Multiple Switchboard--Busy Test--Influence of Traffic--Magneto-Multiple Switchboard--Multiple Boards: Series, Branch-Terminal, Modern Magneto, Common-Battery--Western Electric No. 1 Relay Board--Western Electric No. 10 Board--Types of Multiple Boards--Apparatus--Trunking--Western Electric and Kellogg Trunk Circuits AUTOMATIC SYSTEMS _By K. B. Miller and S. G. McMeen_ Page 135 Automatic vs. Manual--Operation--Selecting Switch--Line Switch--Trunking Systems--Two- and Three-Wire Systems--Subscriber's Station Apparatus--First and Second Selector Operation--Connector--Release after Conversation--Multi-Office System--Automatic Sub-Offices--Rotary Connector--Party Lines--Two-Wire Automatic System--Lorimer System--Central-Office Apparatus--Operation--Automanual System--Operation--Subscriber's Apparatus--Operator's Equipment--Switching Equipment--Distribution of Calls--Connection--Speed POWER PLANTS AND BUILDINGS _By K. B. Miller and S. G. McMeen_ Page 227 Currents Employed--Types--Operator's Transmitter Supply--Ringing-Current Supply--Auxiliary Signaling Current--Primary Sources--Duplicate Apparatus--Storage Batteries--Power Switchboards--Circuits--Central-Office Building--Arrangement of Apparatus--Manual Offices--Automatic Offices SPECIAL SERVICE FEATURES _By K. B. Miller and S. G. McMeen_ Page 271 Private-Branch Exchanges--Switchboards--Supervision--With Automatic Offices--Battery Supply--Ringing Current--Inter-Communicating Systems--Magneto System--Common-Battery Systems--Types--Long-Distance Switching--Operator's Orders--Trunking--Way Stations--Traffic--Measured Service--Charging--Rates--Toll Service--Local Service TELEGRAPH AND RAILWAY WORK _By K. B. Miller and S. G. McMeen_ Page 321 Phantom, Simplex, and Composite Circuits--Ringing--Railway Composite--Telephone Train Dispatching--Railroad Conditions--Transmitting Orders--Apparatus--Telephone Equipment--Types of Circuits--Test Boards--Blocking Sets--Dispatching on Electric Railways REVIEW QUESTIONS Page 359 INDEX Page 373 [Footnote A: For professional standing of authors, see list of Authors and Collaborators at front of volume.] [Footnote B: For page numbers, see foot of pages.] [Illustration: PORTION OF TERMINAL ROOM OF LARGE COMMON-BATTERY OFFICE Prospect Office, New York Telephone Co.] CHAPTER XXII THE SIMPLE COMMON-BATTERY SWITCHBOARD =Advantages of Common-Battery Operation.= The advantages of the common-battery system of operation, alluded to in Chapter XIII, may be briefly summarized here. The main gain in the common-battery system of supply is the simplification of the subscribers' instruments, doing away with the local batteries and the magneto generators, and the concentration of all these many sources of current into one single source at the central office. A considerable saving is thus effected from the standpoint of maintenance, since the simpler common-battery instrument is not so likely to get out of order and, therefore, does not have to be visited so often for repairs, and the absence of local batteries, of course, makes the renewal of the battery parts by members of the maintenance department, unnecessary. Another decided advantage in the common-battery system is the fact that the centralized battery stands ready always to send current over the line when the subscriber completes the circuit of the line at his station by removing his receiver from its hook. The common-battery system, therefore, lends itself naturally to the purposes of automatic signaling, since it is only necessary to place at the central office a device in the circuit of each line that will be responsive to the current which flows from the central battery when the subscriber removes his receiver from its hook. It is thus that the subscriber is enabled automatically to signal the central office when he desires a connection; and as will be shown, it is by the same sort of means, associated with the cord circuits used in connecting his line with some other line, that the operator is automatically notified when a disconnection is desired, the cessation of current through the subscriber's line when he hangs up his receiver being made to actuate certain responsive devices which are associated with the cord at that time connected with his line, and which convey the proper disconnect signal to the operator. Concentration of sources of energy into a single large unit, the simplification of the subscriber's station equipment, and the ready adaptability to automatic signaling from the subscriber to the central office are, therefore, the reasons for the existence of the common-battery system. =Common Battery vs. Magneto.= It must not be supposed, however, that the common-battery system always has advantages over the magneto system, and that it is superior to the magneto or local-battery system for all purposes. It is the outward attractiveness of the common-battery system and the arguments in its favor, so readily made by over-zealous salesmen, that has led, in many cases, to the adoption of this system when the magneto system would better have served the purpose of utility and economy. To say the least, the telephone transmission to be had from common-battery systems is no better than that to be had from local-battery systems, and as a rule, assuming equality in other respects, it is not as good. It is perhaps true, however, that under average conditions common-battery transmission is somewhat better, because whereas the local batteries at the subscribers' stations in the local-battery system are not likely to be in uniformly first-class condition, the battery in a common-battery system will be kept up to its full voltage except under the grossest neglect. The places in which the magneto, or local-battery, system is to be preferred to the common-battery system, in the opinion of the writers, are to be found in the small rural communities where the lines have a rather great average length; where a good many subscribers are likely to be found on some of the lines; where the sources of electrical power available for charging storage batteries are likely either not to exist, or to be of a very uncertain nature; and where it is not commercially feasible to employ a high-grade class of attendants, or, in fact, any attendant at all other than the operator at the central office. In large or medium-sized exchanges it is always possible to procure suitable current for charging the storage batteries required in common-battery systems, and it is frequently economical, on account of the considerable quantity of energy that is thus used, to establish a generating plant in connection with the central office for developing the necessary electrical energy. In very small rural places there are frequently no available sources of electrical energy, and the expense of establishing a power plant for the purpose cannot be justified. But even if there is an electric light or railway system in the small town, so that the problem of available current supply does not exist, the establishment of a common-battery system with its storage battery and the necessary charging machinery requires the daily attendance at the central office of some one to watch and care for this battery, and this, on account of the small gross revenue that may be derived from a small telephone system, often involves a serious financial burden. There is no royal road to a proper decision in the matter, and no sharp line of demarcation may be drawn between the places where common-battery systems are superior to magneto and _vice versâ_. It may be said, however, that in the building of all new telephone plants having over about 500 local subscribers, the common-battery system is undoubtedly superior to the magneto. If the plant is an old one, however, and is to be re-equipped, the continuance of magneto apparatus might be justified for considerably larger exchanges than those having 500 subscribers. Telephone operating companies who have changed over the equipment of old plants from magneto to common battery have sometimes been led into rather serious difficulty, owing to the fact that their lines, while serving tolerably well for magneto work, were found inadequate to meet the more exacting demands of common-battery work. Again in an old plant the change from magneto to common-battery equipment involves not only the change of switchboards, but also the change of subscribers' instruments that are otherwise good, and this consideration alone often, in our opinion, justifies the replacing of an old magneto board with a new magneto board, even if the exchange is of such size as to demand a small multiple board. Where the plant to be established is of such size as to leave doubt as to whether a magneto or a common-battery switchboard should be employed, the questions of availability of the proper kind of power for charging the batteries, the proper kind of help for maintaining the batteries and the more elaborate central-office equipment, the demands and previous education of the public to be served, all are factors which must be considered in reaching the decision. It is not proper to say that anything like all exchanges having fewer than 500 local lines, should be equipped with magneto service. Where all the lines are short, where suitable power is available, and where a good grade of attendants is available--as, for instance, in the case of private telephone exchanges that serve some business establishment or other institution located in one building or a group of buildings--the common-battery system is to be recommended and is largely used, even though it may have but a dozen or so subscribers' lines. It is for such uses, and for use in those regular public-service exchange systems where the conditions are such as to warrant the common-battery system, and yet where the number of lines and the traffic are small enough to be handled by such a small group of operators that any one of them may reach over the entire face of the board, that the simple non-multiple common-battery system finds its proper field of usefulness. =Line Signals.= The principles and means by which the subscriber is enabled to call the central-office operator in a common-battery system have been referred to briefly in Chapter III. We will review these at this point and also consider briefly the way in which the line signals are associated with the connective devices in the subscribers' lines. _Direct-Line Lamp._ The simplest possible way is to put the line signal directly in the circuit of the line in series with the central-office battery, and so to arrange the jack of the corresponding line that the circuit through the line signal will be open when the operator inserts a plug into that jack. This arrangement is shown in Fig. 307 where the subscriber's station at the left is indicated in the simplest of its forms. It is well to repeat here that in all common-battery manual systems, the subscriber's station equipment, regardless of the arrangement or type of its talking and signaling apparatus, must have these features: First, that the line shall be normally open to direct currents at the subscriber's station; second, that the line shall be closed to direct currents when the subscriber removes his receiver from its hook in making or in answering a call; third, that the line normally, although open to direct currents, shall afford a proper path for alternating or varying currents through the signal receiving device at the sub-station. The subscriber's station arrangement shown in Fig. 307, and those immediately following, is the simplest arrangement that possesses these three necessary features for common-battery service. [Illustration: Fig. 307. Direct-Line Lamp] Considering the arrangement at the central office, Fig. 307, the two limbs of the line are permanently connected to the tip and sleeve contacts of the jack. These two main contacts of the jack normally engage two anvils so connected that the tip of the jack is ordinarily connected through its anvil to ground, while the sleeve of the jack is normally connected through its anvil to a circuit leading through the line signal--in this case a lamp--and the common battery, and thence to ground. The operation is obvious. Normally no current may flow from the common battery through the signal because the line is open at the subscriber's station. The removal of the subscriber's receiver from its hook closes the circuit of the line and allows the current to flow through the lamp, causing it to glow. When the operator inserts the plug into the jack, in response to the call, the circuit through the lamp is cut off at the jack and the lamp goes out. This arrangement, termed the direct-line lamp arrangement, is largely used in small common-battery telephone systems where the lines are very short, such as those found in factories or other places where the confines of the exchange are those of a building or a group of neighboring buildings. Many of the so-called private-branch exchanges, which will be considered more in detail in a later chapter, employ this direct-line lamp arrangement. [Illustration: Fig. 308. Direct-Line Lamp with Ballast] _Direct-Line Lamp with Ballast._ Obviously, however, this direct-line lamp arrangement is not a good one where the lines vary widely in length and resistance. An incandescent lamp, as is well known, must not be subjected to too great a variation in current. If the current that is just right in amount to bring it to its intended degree of illumination is increased by a comparatively small amount, the life of the lamp will be greatly shortened, and too great an increase will result in the lamp's burning out immediately. On the other hand, a current that is too small will not result in the proper illumination of the lamp, and a current of one-half the proper normal value will just suffice to bring the lamp to a dull red glow. With lines that are not approximately uniform in length and resistance the shorter lines would afford too great a flow of current to the lamps and the longer lines too little, and there is always the danger present, unless means are taken to prevent it, that if a line becomes short-circuited or grounded near the central office, the lamp will be subjected to practically the full battery potential and, therefore, to such a current as will burn it out. One of the very ingenious and, we believe, promising methods that has been proposed to overcome this difficulty is that of the iron-wire ballast, alluded to in Chapter III. This, it will be remembered, consists of an iron-wire resistance enclosed in a vacuum chamber and so proportioned with respect to the flow of current that it will be subjected to a considerable heating effect by the amount of current that is proper to illuminate the lamp. As has already been pointed out, carbon has a negative temperature coefficient, that is, its resistance decreases when heated. Iron, on the other hand, has a positive temperature coefficient, its resistance increasing when heated. When such an iron-wire ballast is put in series with the incandescent lamp forming the line signal, as shown in Fig. 308, it is seen that the resistance of the carbon in the lamp filament and of the iron in the ballast will act in opposite ways when the current increases or decreases. An increase of current will tend to heat up the iron wire of the ballast and, therefore, increase its resistance, and the ballast is so proportioned that it will hold the current that may flow through the lamp within the proper maximum and minimum limits, regardless of the resistance of the line in which the lamp is used. This arrangement has not gone into wide use up to the present time. _Line Lamp with Relay._ By far the most common method of associating the line lamp with the line is to employ a relay, of which the actuating coil is in the line circuit, this relay serving to control a local circuit containing the battery and the lamp. This arrangement and the way in which these parts are associated with the jack are clearly indicated in Fig. 309. Here the relay may receive any amount of current, from the smallest which will cause it to pull up its armature, to the largest which will not injure its winding by overheat. Relays may be made which will attract their armatures at a certain minimum current and which will not burn out when energized by currents about ten times as large, and it is thus seen that a very large range of current through the relay winding is permissible, and that, therefore, a very great latitude as to line resistance is secured. On the other hand, it is obvious that the lamp circuit, being entirely local, is of uniform resistance, the lamp always being subjected, in the arrangement shown, to practically the full battery potential, the lamp being selected to operate on that potential. [Illustration: Fig. 309. Line Lamp with Relay] _Pilot Signals._ In the circuits of Figs. 307, 308, and 309, but a single line and its associated apparatus is shown, and it may not be altogether clear to the uninitiated how it is that the battery shown in those figures may serve, without interference of any function, a larger number of lines than one. It is to be remembered that this battery is the one which serves not only to operate the line signals, but also to supply talking current to the subscribers and to supply current for the operation of the cord-circuit signals after the cord circuits are connected with the lines. In Fig. 310 this matter is made clear with respect to the association of this common battery with the lines for operating the line signals, and also another important feature of common-battery work is brought out, viz, the pilot lamp and its association with a group of line lamps. Three subscribers' lines only are shown, but this serves clearly to illustrate the association of any larger number of lines with the common battery. Ignoring at first the pilot relay and the pilot lamp, it will be seen that each of the tip-spring anvils of the jacks is connected to a common wire _1_ which is grounded. Each of the sleeve-contact anvils is connected through the coil of the line relay to another common wire _2_, which connects with the live side of the common battery. Obviously, therefore, this arrangement corresponds with that of Fig. 309, since the battery may furnish current to energize any one of the line relays upon the closure of the circuit of the corresponding line. Each of the relay armatures in Fig. 310 is connected to ground. Here we wish to bring out an important thing about telephone circuit diagrams which is sometimes confusing to the beginner, but which really, when understood, tends to prevent confusion. The showing of a separate ground for each of the line-relay armatures does not mean that literally each one of these armatures is connected by a separate wire to earth, and it is to be understood that the three separate grounds shown in connection with these relay armatures is meant to indicate just such a set of affairs as is shown in connection with the tip-spring anvils of the jacks, all of which are connected to a common wire which, in turn, is grounded. Obviously, the result is the same, but in the case of this particular diagram it is seen that a great deal of crossing of lines is prevented by showing a separate ground at each one of the relay armatures. The same practice is followed in connection with the common battery. Sometimes it is very inconvenient in a complicated diagram to run all of the wires that are supposed to connect with one terminal of the battery across the diagram to represent this connection. It is permissible, therefore, and in fact desirable, that separate battery symbols be shown wherever by so doing the diagram will be simplified, the understanding being, in the absence of other information or of other indications, that the same battery is referred to, just as the same ground is referred to in connection with the relay armatures in the figure under discussion. Each line lamp in Fig. 310 is shown connected on one hand to its corresponding line relay contact and on the other hand to a common wire which leads through the winding of the pilot relay to the live side of the battery. It is obvious here that whenever any one of the line relays attracts its armature the local circuit containing the corresponding lamp and the common battery will be closed and the lamp illuminated. Whenever any line relay operates, the current, which is supplied to its lamp, must come through the pilot-relay winding, and if a number of line relays are energized, then the current flow of the corresponding lamps must flow through this relay winding. Therefore, this relay winding must be of low resistance, so that the drop through its winding may not be sufficient to interfere with the proper burning of the lamps, even though a large number of lamps be fed simultaneously through it. The pilot relay must be so sensitive that the current, even through one lamp, will cause it to attract its armature. When it does attract its armature it causes illumination of the pilot lamp in the same way that the line relays cause the illumination of the line lamps. The pilot lamp, which is commonly associated with a group of line lamps that are placed on any one operator's position of the switchboard, is located in a conspicuous place in the switchboard cabinet and is provided with a larger lens so as to make a more striking signal. As a result, whenever any line lamp on a given position lights, the pilot lamp does also and serves to attract the attention, even of those located in distant portions of the room, to the fact that a call exists on that position of the board, the line lamp itself, which is simultaneously lighted, pointing out the particular line on which the call exists. Pilot lamps, in effect, perform similar service to the night alarm in magneto boards, but, of course, they are silent and do not attract attention unless within the range of vision of the operator. They are used not only in connection with line lamps, but also in connection with the cord-circuit lamps or signals, as will be pointed out. [Illustration: Fig. 311. Battery Supply Through Impedance Coils] [Illustration: Fig. 312. Battery Supply through Repeating Coils] [Illustration: Fig. 313. Battery Supply with Impedance Coils and Condensers] =Cord Circuit.= _Battery Supply._ Were it not for the necessity of providing for cord-circuit signals in common-battery switchboards, the common-battery cord circuit would be scarcely more complex than that for magneto working. Stripped of all details, such as signals, ringing and listening keys, and operator's equipment, cord circuits of three different types are shown in Figs. 311, 312, and 313. These merely illustrate the way in which the battery is associated with the cord circuits and through them with the line circuits for supplying current for talking purposes to the subscribers. It is thought that this matter will be clear in view of the discussion of the methods by which current is supplied to the subscribers' transmitters in common-battery systems as discussed in Chapter XIII. While the arrangements in this respect of Figs. 311, 312, and 313 illustrate only three of the methods, these three are the ones that have been most widely and successfully used. _Supervisory Signals._ The signals that are associated with the cord circuits are termed supervisory signals because of the fact that by their means the operator is enabled to supervise the condition of the lines during times when they are connected for conversation. The operation of these supervisory signals may be best understood by considering the complete circuits of a simple switchboard and must be studied in conjunction with the circuits of the lines as well as those of the cords. [Illustration: Fig. 314. Simple Common-Battery Switchboard] _Complete Circuit._ Such complete circuits are shown in Fig. 314. The particular arrangement indicated is that employed by the Kellogg Company, and except for minor details may be considered as typical of other makes also. Two subscribers' lines are shown extending from Station A and Station B, respectively, to the central office. The line wires are shown terminating in jacks in the same manner as indicated in Figs. 307, 308, and 309, and their circuits are normally continued from these jacks to the ground on one side and to the line relay and battery on the other. The jack in this case has three contacts adapted to register with three corresponding contacts in each of the plugs. The thimble of the jack in this case forms no part of the talking circuit and is distinct from the two jack springs which form the line terminals. It and the auxiliary contact _1_ in each of the plugs with which it registers, are solely for the purpose of co-operating in the control of the supervisory signals. The tip and sleeve strands of the cord are continuous from one plug to the other except for the condensers. The two batteries indicated in connection with the cord circuit are separate batteries, a characteristic of the Kellogg system. One of these batteries serves to supply current to the tip and sleeve strand of the cord circuit through the two windings _3_ and _4_, respectively, of the supervisory relay connected with the answering side of the cord circuit, while the other battery similarly supplies current through the windings _5_ and _6_ of the supervisory relay associated with the calling side of the cord circuit. The windings of these relays, therefore, act as impedance coils and the arrangement by which battery current is supplied to the cord circuits and, therefore, to the lines of the connected subscribers, is seen to be the combined impedance coil and condenser arrangement discussed in Chapter XIII. As soon as a plug is inserted into the jack of a line, the line relay will be removed from the control of the line, and since the two strands of the cord circuit now form continuations of the two line conductors, the supervisory relay will be substituted for the line relay and will be under control of the line. Since all of the current which passes to the line after a plug is inserted must pass through the cord-circuit connection and through the relay windings, and since current can only flow through the line when the subscriber's receiver is off its hook, it follows that the supervisory relays will only be energized after the corresponding plug has been inserted into a jack of the line and after the subscriber has removed his receiver. Unlike the line relays, the supervisory relays open their contacts to break the local circuits of the supervisory lamps _7_ and _8_ when the relay coils are energized, and to close them when de-energized; but the armatures of the supervisory relays do alone control the circuits of the supervisory lamps. These circuits are normally held open in another place, that is, between the plug contacts _1_ and the jack thimbles. It is only, therefore, when a plug is inserted into a jack and when the supervisory relay is de-energized, that the supervisory lamp may be lighted. When a plug is inserted into a jack and when the corresponding supervisory relay is de-energized, the circuit may be traced from ground at the cord-circuit batteries through the left-hand battery, for instance, through lamp _7_, thence through the contacts of the supervisory relay to the contact _1_ of the plug, thence through the thimble of the jack to ground. When a plug is inserted into the jack, therefore, the necessary arrangements are completed for the supervisory lamp to be under the control of the subscriber. Under this condition, whenever the subscriber's receiver is on its hook, the circuit of the line will be broken, the supervisory relay will be de-energized, and the supervisory lamp will be lighted. When, on the other hand, the subscriber's receiver is off its hook, the circuit of the line will be complete, the supervisory relay will be energized, and the supervisory lamp will be extinguished. _Salient Features of Supervisory Operation._ It will facilitate the student's understanding of the requirements and mode of operation of common-battery supervisory signals in manual systems, whether simple or multiple, if he will firmly fix the following facts in his mind. In order that the supervisory signal may become operative at all, some act must be performed by the operator--this being usually the act of plugging into a jack--and then, until the connection is taken down, the supervisory signal is under the control of the subscriber, and it is displayed only when the subscriber's receiver is placed on its hook. _Cycle of Operations._ We may now trace through the complete cycle of operations of the simple common-battery switchboard, the circuits of which are shown in Fig. 314. Assume all apparatus in its normal condition, and then assume that the subscriber at Station A removes his receiver from its hook. This pulls up the line relay and lights the line lamp, the pilot relay also pulling up and lighting the common pilot lamp which is not shown. In response to this call, the operator inserts the answering plug and throws her listening key _L.K._ The operator's talking set is thus bridged across the cord circuit and she is enabled to converse with the calling subscriber. The answering supervisory lamp _7_ did not light when the operator inserted the answering plug into the jack, because, although the contacts in the lamp circuit were closed by the plug contact _1_ engaging the thimble of the jack, the lamp circuit was held open by the attraction of the supervisory relay armature, the subscriber's receiver being off its hook. Learning that the called-for subscriber is the one at Station B, the operator inserts the calling plug into the jack at that station and presses the ringing key _R.K._, in order to ring the bell. The act of plugging in, it will be remembered, cuts off the line-signaling apparatus from connection with that line. As the subscriber at Station B was not at his telephone when called and his receiver was, therefore, on its hook, the insertion of the calling plug did not energize the supervisory relay coils _5_ and _6_, and, therefore, that relay did not attract its armature. The supervisory lamp _8_ was thus lighted, the circuit being from ground through the right-hand cord-circuit battery, lamp _8_, back contacts of the supervisory relay, third strand of the cord to contact _1_ of the calling plug, and thence to ground through the thimble of the jack. The lighting of this lamp is continued until the party at Station B responds by removing his receiver from its hook, which completes the line circuit, energizes relay windings _5_ and _6_, causes that relay to attract its armature, and thus break the circuit of the lamp _8_. Both supervisory lamps remain out as long as the two subscribers are conversing, but when either one of them hangs up his receiver the corresponding supervisory relay becomes de-energized and the corresponding lamp lights. When both of the lamps become illuminated, the operator knows that both subscribers are through talking and she takes down the connection. Countless variations have been worked in the arrangement of the line and cord circuits, but the general mode of operation of this particular circuit chosen for illustration is standard and should be thoroughly mastered. The operation of other arrangements will be readily understood from an inspection of the circuits, once the fundamental mode of operation that is common to all of them is well in mind. =Lamps.= The incandescent lamps used in connection with line and supervisory signals are specially manufactured, but differ in no sense from the larger lamps employed for general lighting purposes, save in the details of size, form, and method of mounting. Usually these lamps are rated at about one-third candle-power, although they have a somewhat larger candle-power as a rule. They are manufactured to operate on various voltages, the most usual operating pressures being 12, 24, and 48 volts. The 24-volt lamp consumes about one-tenth of an ampere when fully illuminated, the lamp thus consuming about 2.4 watts. The 12- and 48-volt lamps consume about the same amount of energy and corresponding amounts of current. [Illustration: Fig. 315. Switchboard Lamp] _Lamp Mounting._ The usual form of screw-threaded mounting employed in lamps for commercial lighting was at first applied to the miniature lamps used for switchboard work, but this was found unsatisfactory and these lamps are now practically always provided with two contact strips, one on each side of the glass bulb, these strips forming respectively the terminals for the two ends of the filament within. Such a construction of a common form of lamp is shown in Fig. 315, where these terminals are indicated by the numerals _1_ and _2_, _3_ being a dry wooden block arranged between the terminals at one end for securing greater rigidity between them. [Illustration: Fig. 316. Line Lamp Mounting] The method of mounting these lamps is subject to a good deal of variation in detail, but the arrangement is always such that the lamp is slid in between two metallic contacts forming terminals of the circuit in which the lamp is to operate. Such an arrangement of springs and the co-operating mounting forming a sort of socket for the reception of switchboard lamps is referred to as a _lamp jack_. These are sometimes individually mounted and sometimes mounted in strips in much the same way that jacks are mounted in strips. A strip of lamp jacks as manufactured by the Kellogg Company is shown in Fig. 316. The opalescent lens is adapted to be fitted in front of the lamp after it has been inserted into the jack. Fig. 317 gives an excellent view of an individually-mounted lamp jack with its lamp and lens, this also being of Kellogg manufacture. This figure shows a section of the plug shelf which is bored to receive a lamp. In order to protect the lamps and lenses from breakage, due to the striking of the plugs against them, a metal shield is placed over the lens, as shown in this figure, this being so cut away as to allow sufficient openings for the light to shine through. Sometimes instead of employing lenses in front of the lamps, a flat piece of translucent material is used to cover the openings of the lamp, this being protected by suitable perforated strips of metal. A strip of lamp jacks employing this feature is shown in Fig. 318, this being of Dean manufacture. An advantage of this for certain types of work is that the flat translucent plate in front of the lamp may readily carry designating marks, such as the number of the line or something to indicate the character of the line, which marks may be readily changed as required. [Illustration: Fig. 317. Supervisory Lamp Mounting] [Illustration: Fig. 318. Line Lamp Mounting] [Illustration: Fig. 319. Individual Lamp Jacks] In the types made by some manufacturers the only difference between the pilot lamp and the line lamp is in the size of the lens in front of it, the jack and the lamp itself being the same for each, while others use a larger lamp for the pilot. In Fig. 319 are shown two individual lamp jacks, the one at the top being for supervisory lamps and the one at the bottom being provided with a large lens for serving as a pilot lamp. [Illustration: TERMINAL ROOM APPARATUS IN PROCESS OF INSTALLATION Installed by Dean Electric Company at Detroit, Mich.] =Mechanical Signals.= As has been stated the so-called mechanical signals are sometimes used in small common-battery switchboards instead of lamps. Where this is done the coil of the signal, if it is a line signal, is substituted in the line circuit in place of the relay coil. If the signals are used in connection with cord circuits for supervisory signals, their coils are put in the circuit in place of the supervisory relay coils. (These signals are referred to in Chapter III in connection with Fig. 23.) They are so arranged that the attraction of the armature lifts a target on the end of a lever, and this causes a display of color or form. The release of the armature allows this target to drop back, thus obliterating the display. Such signals, often called _visual signals_ and _electromagnet signals_, should be distinguished from the drops considered in connection with magneto switchboards in which the attraction of the armature causes the display of the signal by the falling of a drop, the signal remaining displayed until restored by some other means, the restoration depending in no wise on when the armature is released. _Western Electric._ The mechanical signal of the Western Electric Company, shown in Fig. 320, has a target similar to that shown in Fig. 254 but without a latch. It is turned to show a different color by the attraction of the armature and allowed to resume its normal position when the armature is released. [Illustration: Fig. 320. Mechanical Signal] _Kellogg._ Fig. 321 gives a good idea of a strip of mechanical signals as manufactured by the Kellogg Company. This is known as the _gridiron_ signal on account of the cross-bar striping of its target. The white bars on the target normally lie just behind the cross-bars on the shield in front, but a slight raising of the target--about one-eighth of an inch--exposes these white bars to view, opposite the rectangular openings in the front shield. [Illustration: Fig. 321. Strip of Gridiron Signals] _Monarch._ In Fig. 322 is shown the visual signal manufactured by the Monarch Telephone Company. [Illustration: Fig. 322. Mechanical Signal] =Relays.= The line relays for common-battery switchboards likewise assume a great variety of forms. The well-known type of relay employed in telegraphy would answer the purpose well but for the amount of room that it occupies, as it is sometimes necessary to group a large number of relays in a very small space. Nearly all present-day relays are of the single-coil type, and in nearly all cases the movement of the armature causes the movement of one or more switching springs, which are thus made to engage or disengage their associated spring or springs. One of the most widely used forms of relays has an L-shaped armature hung across the front of a forwardly projecting arm of iron, on the knife-edge corner of which it rocks as moved by the attraction of the magnet. The general form of this relay was illustrated in Fig. 95. Sometimes this relay is made up in single units and frequently a large number of such single units are mounted on a single mounting plate. This matter will be dealt with more in detail in the discussion of common-battery multiple switchboards. In other cases these relays are built _en bloc_, a rectangular strip of soft iron long enough to afford space for ten relays side by side being bored out with ten cylindrical holes to receive the electromagnets. The iron of the block affords a return path for the lines of force. The L-shaped armatures are hung over the front edge of this block, so that their free ends lie opposite the magnet cores within the block. This arrangement as employed by the Kellogg Company is shown in two views in Figs. 323 and 324. [Illustration: Fig. 323. Strip of Relays] [Illustration: Fig. 324. Strip of Relays] A bank of line relays especially adapted for small common-battery switchboards as made by the Dean Company, is shown in Fig. 325. [Illustration: Fig. 325. Bank of Relays] =Jacks.= The jacks in common-battery switchboards are almost always mounted in groups of ten or twenty, the arrangement being similar to that discussed in connection with lamp strips. Ordinarily in common-battery work the jack is provided with two inner contacts so as to cut off both sides of the signaling circuit when the operator plugs in. A strip of such jacks is shown in Fig. 326. [Illustration: Fig. 326. Strip of Cut-Off Jacks] Ringing and listening keys for simple common-battery switchboards differ in no essential respect from those employed in magneto boards. [Illustration: Fig. 327. Details of Lamp, Plug, and Key Mounting] =Switchboard Assembly.= The general assembly of the parts of a simple common-battery switchboard deserves some attention. The form of the switchboard need not differ essentially from that employed in magneto work, but ordinarily the cabinet is somewhat smaller on account of the smaller amount of room required by its lamps and jacks. An excellent idea of the line jacks and lamps, plugs, keys, and supervisory signals may be obtained from Fig. 327, which is a detail view taken from a Kellogg board. In the vertical panel of the board above the plug shelf are arranged the line jacks and the lamps in rows of twenty each, each lamp being immediately beneath its corresponding jack. Such jacks are ordinarily mounted on 1/2-inch centers both vertically and horizontally, so that a group of one hundred lamps and line jacks will occupy a space only slightly over 10 by 5 inches. Such economy of space is not required in the simple magneto board, because the space might easily be made larger without in any way taxing the reach of the operator. The reason for this comparatively close mounting is a result, not of the requirements of the simple non-multiple common-battery board itself, but of the fact that the jack strips and lamp strips, which are required in very large numbers in multiple boards, have to be mounted extremely close together, and as the same lamp strips and jack strips are often available for simple switchboards, an economy in manufacture is effected by adherence to the same general dimensions. [Illustration: Fig. 328. Simple Common-Battery Switchboard with Removable Relay Panel] A rear view of a common form of switchboard cabinet, known as the _upright type_ and manufactured by the Dean Company, is shown in Fig. 328. In this all the relays are mounted on a hinged rack, which, when opened out as indicated, exposes the wiring to view for inspection or repairs. Access to both sides of the relays is thus given to the repairman who may do all his work from the rear of the board without disturbing the operator. Fig. 329 shows a three-position cabinet of Kellogg manufacture, this being about the limit in size of boards that could properly be called simple. Obviously, where a switchboard cabinet must be made of greater length than this, _i. e._, than is required to accommodate three operators, it becomes too long for the operators to reach all over it without undue effort or without moving from their seats. The so-called _transfer board_ and the _multiple board_ (to be considered in subsequent chapters), constitute methods of relief from such a condition in larger exchanges. [Illustration: Fig. 329. Three-Position Lamp Board] CHAPTER XXIII TRANSFER SWITCHBOARD When the traffic originating in a switchboard becomes so great as to require so many operators that the board must be made so long that any one of the operators cannot reach over its entire face, the simple switchboard does not suffice. Either some form of transfer switchboard or of multiple switchboard must be used. In this chapter the transfer switchboard will be briefly discussed. The transfer switchboard is so named because its arrangement is such that some of the connections through it are handled by means of two operators, the operator who answers the call transferring it to another operator who completes the connection desired. =Limitations of Simple Switchboard.= Conceive a number of simple magneto switchboards, or a number of common-battery switchboards, arranged side by side, their number being so great as to form, by their combination, a board too long for the ordinary cords and plugs to reach between its extremities. On each of these simple switchboards, which we will say are each of the one-position type, there terminates a group of subscribers' lines so great in number, considering the traffic on them, that the efforts of one operator will just about be taxed to properly attend to their calls during the busiest hours of the day. If, now, these subscribers would be sufficiently accommodating to call for no other subscribers than those whose lines terminate on the same switchboard section or on one of the immediately adjacent switchboard sections, all would be well, but subscribers will not be so restricted. They demand universal service; that is, they demand the privilege of having their own lines connected with the line of any other person in the exchange. Obviously, in the arrangement just conceived, any operator may answer any call originating at her own board and complete the connection with the desired subscriber if that subscriber's jack terminates on her own section or on one of the adjacent ones. Beyond that she is powerless unless other means are provided. =Transfer Lines.= In the transfer board these other means consist in the provision of groups of local trunk lines or transfer lines extending from each switchboard position to each other non-adjacent switchboard position. When an operator receives a call for some line on a non-adjacent position, having answered this call with her answering plug, she inserts the calling plug into the jack of one of these transfer lines that leads to the proper other section. The operator at that section is notified either verbally or by signal, and she completes the connection between the other end of the transfer line and the line of the called subscriber; the connection between the two subscribers thus being effected through the cords of the two operators in question linked together by the transfer line. Such a transfer line as just described, requiring the connection at each of its ends by one of the plugs of the operator's cord pair, is termed a _jack-ended trunk_ or a _jack-ended transfer line_ because each of its ends terminates in a jack. [Illustration: Fig. 330. Jack-Ended Transfer Circuit] There is another method of accomplishing the same general result by the employment of the so-called _plug-ended trunk_ or _plug-ended transfer line_. In this the trunk or transfer line terminates at one end, the answering end, in a jack as before, and the connection is made with it by the answering operator by means of the calling plug of the pair with which she answered the originating call. The other end of this trunk, instead of terminating in a jack, ends in a plug and the second operator involved in the connection, after being notified, picks up this plug and inserts it in the jack of the called subscriber, thus completing the connection without employing one of her regular cord pairs. _Jack-Ended Trunk._ In Fig. 330 are shown the circuits of a commonly employed jack-ended trunk for transfer boards. The talking circuit, as usual, is shown in heavy lines and terminates in the tip and sleeve of the transfer jacks at each end. The auxiliary contacts in these jacks and the circuits connecting them are absolutely independent of the talking circuit and are for the purpose of signaling only, the arrangement of the jacks being such that when a plug is inserted, the spring _1_ will break from spring _2_ and make with spring _3_. Obviously, the insertion of a plug in either of the jacks will establish such connections as to light both lamps, since the engagement of spring _1_ with spring _3_ in either of the jacks will connect both of the lamps in multiple across the battery, this connection including always the contacts _1_ and _2_ of the other jack. From this it follows that the insertion of a plug in the other end of the trunk will, by breaking contact between springs _1_ and _2_, put out both the lamps. One plug inserted will, therefore, light both lamps; two plugs inserted or two plugs withdrawn will extinguish both lamps. [Illustration: Fig. 331. Jack-Ended Transfer Circuit] If an operator located at one end of this trunk answers a call and finds that the called-for subscriber's line terminates within reach of the operator near the other end of this trunk, she will insert a calling plug, corresponding to the answering plug used in answering a call, into the jack of this trunk and thus light the lamp at both its ends. The operator at the other end upon seeing this transfer lamp illuminated inserts one of her answering plugs into the jack, and by means of her listening key ascertains the number of the subscriber desired, and immediately inserts her calling plug into the jack of the subscriber wanted and rings him in the usual manner. The act of this second operator in inserting her answering plug into the jack extinguishes the lamp at her own end and also at the end where the call originated, thus notifying the answering operator that the call has been attended to. As long as the lamps remain lighted, the operators know that there is an unattended connection on that transfer line. Such a transfer line is called a _two-way_ line or a _single-track_ line, because traffic over it may be in either direction. In Fig. 331 is shown a trunk that operates in a similar way except that the two lamps, instead of being arranged in multiple, are arranged in series. [Illustration: Fig. 332. Jack- and Plug-Ended Transfer Circuit] _Plug-Ended Trunk._ In Fig. 332 is shown a plug-ended trunk, this particular arrangement of circuits being employed by the Monarch Company in its transfer boards. This is essentially a one-way trunk, and traffic over it can pass only in the direction of the arrow. Traffic in the opposite direction between any two operators is handled by another trunk or group of trunks similar to this but "pointed" in the other direction. For this reason such a system is referred to as a _double-track_ system. The operation of signals is the same in this case as in Fig. 330, except that the switching device at the left-hand end of the trunk instead of being associated with the jack is associated with the plug seat, which is a switch closely associated with the seat of a plug so as to be operated whenever the plug is withdrawn from or replaced in its seat. The operation of this arrangement is as follows: Whenever an operator at the right-hand end of this trunk receives a call for a subscriber whose line terminates within the reach of the operator at the left-hand end of the trunk, she inserts the calling plug of the pair used in answering the calling subscriber into the jack of the trunk, and thus lights both of the trunk lamps. The operator at the other end of the trunk, seeing the trunk lamp lighted, raises the plug from its seat and, having learned the wishes of the calling subscriber, inserts this plug into the jack of the called subscriber without using one of her regular pairs. When she raised the trunk plug from its seat, she permitted the long spring _1_ of the plug seat switch to rise, thus extinguishing both lamps and giving the signal to the originating operator that the trunk connection has received attention. On taking down the connection, the withdrawal of the plug from the right hand of the trunk lights both lamps, and the restoring of the trunk plug to its normal seat again extinguishes both lamps. =Plug-Seat Switch.= The plug-seat switch is a device that has received a good deal of attention not only for use with transfer systems, but also for use in a great variety of ways with other kinds of manual switching systems. The placing of a plug in its seat or withdrawing it therefrom offers a ready means of accomplishing some switching or signaling operation automatically. The plug-seat switch has, however, in spite of its possibilities, never come into wide use, and so far as we are aware the Monarch Telephone Manufacturing Company is the only company of prominence which incorporates it in its regular output. The Monarch plug-switch mechanism is shown in Fig. 333, and its operation is obvious. It may be stated at this point that one of the reasons why the plug-seat switch has not been more widely adopted for use, is the difficulty that has been experienced due to lint from the switchboard cords collecting on or about the contact points. In the construction given in the detailed cut, upper part, Fig. 333, is shown the means adopted by the Monarch Company for obviating this difficulty. The contact points are carried in the upper portion of an inverted cup mounted on the under side of the switchboard shelf, and are thus protected, in large measure, from the damaging influence of dust and lint. [Illustration: Fig. 333. Plug-Seat Switch] [Illustration: Fig. 334. Order-Wire Arrangement] =Methods of Handling Transfers.= One way of giving the number of the called subscriber to the second operator in a transfer system is to have that operator listen in on the circuit after it is continued to her position and receive the number either from the first operator or from the subscriber. Receiving it from the first operator has the disadvantage of compelling the first operator to wait on the circuit until the second operator responds; receiving it from the subscriber has the disadvantage of sometimes being annoying to him. This, however, is to be preferred to the loss of time on the part of the originating operator that is entailed by the first method. A better way than either of these is to provide between the various operators working in a transfer system, a so-called _order-wire_ system. An order wire, as ordinarily arranged, is a circuit terminating at one end permanently in the head receiver of an operator, and terminating at the other end in a push button which, when depressed, will connect the telephone set of the operator at that end with the order wire. The operator at the push-button end of the order wire may, therefore, at will, communicate with the other operator in spite of anything that the other operator may do. An order-wire system suitable for transfer switchboards consists in an order wire leading from each operator's receiver to a push button at each of the other operator's positions, so that every operator has it within her power to depress a key or button and establish communication with a corresponding operator. When, therefore, an operator in a transfer system answers a call that must be completed through a transfer circuit, she establishes connection with that transfer circuit and then informs the operator at the other end of that circuit by order wire of the number of the trunk and the number of the subscriber with which that trunk is to be connected. Fig. 334 shows a system of order-wire buttons by means of which each operator may connect her telephone set with that of every other operator in the room, the number in this case being confined to three. Assuming that each pair of wires leading from the lower portion of this figure terminates respectively in the operator's talking apparatus of the three respective operators, then it is obvious that operator No. 1, by depressing button No. 2, will connect her telephone set with that of operator No. 2; likewise that any operator may communicate with any other operator by depressing the key bearing the corresponding number. =Limitations of Transfer System.= It may be stated that the transfer system at present has a limited place in the art of telephony. The multiple switchboard has outstripped it in the race for popular approval and has demonstrated its superiority in practically all large manual exchange work. This is not because of lack of effort on the part of telephone engineers to make the transfer system a success in a broad way. A great variety of different schemes, all embodying the fundamental idea of having one operator answer the call and another operator complete it through a trunk line, have been tried. In San Francisco, the Sabin-Hampton system was in fairly successful service and served many thousands of lines for a number of years. It was, however, afterwards replaced by modern multiple switchboards. _Examples of Obsolete Systems._ The Sabin-Hampton system was unique in many respects and involved three operators in each connection. It was one of the very first systems which employed automatic signaling throughout and did away with the subscribers' generators. It did not, however, dispense with the subscribers' local batteries. Another large transfer system, used for years in an exchange serving at a time as many as 5,000, was employed at Grand Rapids, Michigan. This was later replaced by an automatic switchboard. [Illustration: Fig. 335. Three-Position Transfer Switchboard] =Field of Usefulness.= The real field of utility for the transfer system today is to provide for the growth of simple switchboards that have extended beyond their originally intended limits. By the adding of additional sections to the simple switchboard and the establishment of a comparatively cheap transfer system, the simple boards may be made to do continued service without wasting the investment in them by discarding them and establishing a completely new system. However, switchboards are sometimes manufactured in which the transfer system is included as a part of the original equipment. In Fig. 335 is shown a three-position transfer switchboard, manufactured by the Monarch Telephone Company. At first glance the switchboard appears to be exactly like those described in Chapter XXI, but on close observation, the transfer jacks and signals may be seen in the first and third positions, just below the line jacks and signals. There is no transfer equipment in the second position of this switchboard because the operator at that position is able to reach the jacks of all the lines and, therefore, is able to complete all calls originating on her position without the use of any transfer equipment. Referring to Fig. 301, which illustrates a two-position simple switchboard, it may readily be seen that if the demands for telephone service in the locality in which this switchboard is installed should increase so as to require the addition of more switchboard positions, this switchboard could readily be converted to a transfer switchboard by placing the necessary transfer jacks and signals in the vacant space between the line jacks and clearing-out drops. [Illustration: CABLE TURNING SECTIONS, BETWEEN A AND B BOARDS Cortlandt Office, New York Telephone Co.] CHAPTER XXIV PRINCIPLES OF THE MULTIPLE SWITCHBOARD =Field of Utility.= The multiple switchboard, unlike the transfer board, provides means for each operator to complete, without assistance, a connection with any subscriber's line terminating in the switchboard no matter how great the number of lines may be. It is used only where the simple switchboard will not suffice; that is, where the number of lines and the consequent traffic is so great as to require so many operators and, therefore, so great a length of board as to make it impossible for any one operator to reach all over the face of the board without moving from her position. =The Multiple Feature.= The fundamental feature of the multiple switchboard is the placing of a jack for every line served by the switchboard within the reach of every operator. This idea underlying the multiple switchboard may be best grasped by merely considering the mechanical arrangement and grouping of parts without regard to their details of operation. The idea is sometimes elusive, but it is really very simple. If the student at the outset will not be frightened by the very large number of parts that are sometimes involved in multiple switchboards, and by the great complexity which is apparent in the wiring and in the action of these parts; and will remember that this apparent complexity results from the great number of repetitions of the same comparatively simple group of apparatus and circuits, much will be done toward a mastery of the subject. The multiple switchboard is divided into sections, each section being about the width and height that will permit an ordinary operator to reach conveniently all over its face. The usual width of a section brought about by this limitation is from five and one-half to six feet. Such a section affords room for three operators to sit side by side before it. Now each line, instead of having a single jack as in the simple switchboard, is provided with a number of jacks and one of these is placed on each of the sections, so that each one of the operators may have within her reach a jack for each line. It is from the fact that each line has a multiplicity of jacks, that the term multiple switchboard arises. _Number of Sections._ Since there is a jack for each line on each section of the switchboard, it follows that on each section there are as many jacks as there are lines; that is, if the board were serving 5,000 lines there would be 5,000 jacks. Let us see now what it is that determines the number of sections in a multiple switchboard. In the final analysis, it is the amount of traffic that arises in the busiest period of the day. Assume that in a particular office serving 5,000 lines, the subscribers call at such a very low rate that even at the busiest time of the day only enough calls are made to keep, say, three operators busy. In this case there would be no need for the multiple switchboard, for a single section would suffice. The three operators seated before that section would be able to answer and complete the connections for all of the calls that arose. But subscribers do not call at this exceedingly low rate. A great many more calls would arise on 5,000 lines during the busiest hour than could be handled by three operators and, therefore, a great many more operators would be required. Space has to be provided for these operators to work in, and as each section accommodates three operators the total number of sections must be at least equal to the total number of required operators divided by three. Let us assume, for instance, that each operator can handle 200 calls during the busy hour. Assume further that during the busy hour the average number of calls made by each subscriber is two. One hundred subscribers would, therefore, originate 200 calls within this busy hour and this would be just sufficient to keep one operator busy. Since one operator can handle only the calls of one hundred subscribers during the busy hour, it follows that as many operators must be employed as there are hundreds of subscribers whose lines are served in a switchboard, and this means that in an exchange of 5,000 subscribers, 50 operators' positions would be required, or 16-2/3 sections. Each of these sections would be equipped with the full 5,000 jacks, so that each operator could have a connection terminal for each line. _The Multiple._ These groups of 5,000 jacks, repeated on each of the sections are termed multiple jacks, and the entire equipment of these multiple jacks and their wiring is referred to as the multiple. It will be shown presently that the multiple jacks are only used for enabling the operator to connect with the called subscriber. In other words these jacks are for the purpose of enabling each operator to have within her reach any line that may be called for regardless of what line originates the call. We will now consider what arrangements are provided for enabling the operator to receive the signal indicating a call and what provisions are made for her to answer the call in response to such a signal. =Line Signals.= Obviously it is not necessary to have the line signals repeated on each section of the board as are the multiple jacks. If a line has one definite place on the switchboard where its signal may be received and its call may be answered, that suffices. Each line, therefore, in addition to having its multiple jacks distributed one on each section of the switchboard, has a line signal and an individual jack immediately associated with it, located on one only of the sections. This signal usually is in the form of a lamp and is termed the line signal, and this jack is termed the answering jack since it is by means of it that the operator always answers a call in response to the line signal. _Distribution of Line Signals._ It is evident that it would not do to have all of these line signals and answering jacks located at one section of the board for then they would not be available to all of the operators. They are, therefore, distributed along the board in such a way that one group of them will be available to one operator, another group to another operator, and so on; the number of answering jacks and signals in any one group being so proportioned with respect to the number of calls that come in over them during the busy hour that it will afford just about enough calls to keep the operator at that position busy. We may summarize these conditions with respect to the jack and line-signal equipment of the multiple switchboard by saying that each line has a multiple jack on each section of the board and in addition to this has on one section of the board an answering jack and a line signal. These answering jacks and line signals are distributed in groups along the face of the board so that each operator will receive her proper quota of the originating calls which she will answer and, by virtue of the multiple jack, be able to complete the connections with the desired subscribers without moving from her position. =Cord Circuits.= Each operator is also provided with a number of pairs of cords and plugs with proper supervisory or clearing-out signals and ringing and listening keys, the arrangement in this respect being similar to that already described in connection with the simple switchboard. =Guarding against Double Connections.= From what has been said it is seen that a call originating on a given line may be answered at one place only, but an outgoing connection with that line may be made at any position. This fact that a line may be connected with when called for at any one of the sections of the switchboard makes necessary the provision that two or more connections will not be made with the same line at the same time. For instance, if a call came in over a line whose signal was located on the first position of the switchboard for a connection with line No. 1,000, the operator at the first position would connect this calling line with No. 1,000 through the multiple jack on the first section of the switchboard. Assume now that some line, whose signal was located on the 39th position of the switchboard, should call also for line No. 1,000 while that line was still connected with the first calling subscriber. Obviously confusion would result if the operator at the 39th position, not knowing that line No. 1,000 was already busy, should connect this second line with it, thereby leaving both of the calling subscribers connected with line No. 1,000, and as a result all of these three subscribers connected together. The provisions for suitable means for preventing the making of a connection with a line that is already switched at some other section of the switchboard, has offered one of the most fertile fields for invention in the whole telephone art. The ways that have been proposed for accomplishing this are legion. Fortunately common practice has settled on one general plan of action and that is to so arrange the circuits that whenever a line is switched at one section, such an electrical condition will be established on the forward contacts of all of its multiple jacks that any operator at any other section in attempting to make a connection with that line will be notified of the fact that it is already switched by an audible signal, which she will receive in her head receiver. On the other hand the arrangement is such that when a line is not busy, _i. e._, it is not switched at any of the positions of the switchboard, the operator on attempting to make a connection with such a line will receive no such guarding signal and will, therefore, proceed with the connection. We may liken a line in a multiple switchboard to a lane having a number of gates giving access to it. One of these gates--the answering jack--is for the exclusive use of the proprietor of that lane. All of the other gates to the lane--the multiple jacks--are for affording means for the public to enter. But whenever any person enters one of these gates, a signal is automatically put up at all of the other gates forbidding any other person to enter the lane as long as the first person is still within. [Illustration: Fig. 336. Principle of Multiple Switchboard] =Diagram Showing Multiple Board Principle.= For those to whom the foregoing description of the multiple board is not altogether clear, the diagram of Fig. 336 may offer some assistance. Five subscribers' lines are shown running through four sections of a switchboard. Each of these lines is provided with a multiple jack on each section of the board. Each line is also provided with an answering jack and a line signal on one of the sections of the board. Thus the answering jacks and the line signals of lines _1_ and _2_ are shown in Section I, that of line _4_ is shown in Section II, that of line _3_ in Section III, and that of line _5_ in Section IV. At Section I, line _1_ is shown in the condition of having made a call and having had this call answered by the operator inserting one of her plugs into its answering jack. In response to the instructions given by the subscriber, the operator has inserted the other plug of this same pair in the multiple jack of line _2_, thus connecting these two lines for conversation. At Section III, line _3_ is shown as having made a call, and the operator as having answered by inserting one of her plugs into the answering jack. It happens that the subscriber on line _3_ requests a connection with line _1_, and the condition at Section III is that where the operator is about to apply the tip of the calling plug to the jack of line _1_ to ascertain whether or not that line is busy. As before stated, when the contact is made between the tip of the calling plug and the forward contact of the multiple jack, the operator will receive a click in the ear (by means that will be more fully discussed in later chapters), this click indicating to her that line _1_ is not available for connection because it is already switched at some other section of the switchboard. =Busy Test.= The busy signal, by which an operator in attempting to make a connection is informed that the line is already busy, has assumed a great variety of forms and has brought forth many inventions. It has been proposed by some that the insertion of a plug into any one of the jacks of a line would automatically close a little door in front of each of the other jacks of the line, therefore making it impossible for any other operator to insert a plug as long as the line is in use. It has been proposed by others to ring bells or to operate buzzers whenever the attempt was made by an operator to plug into a line that was already in use. Still others have proposed to so arrange the circuits that the operator would get an electric shock whenever she attempted to plug into a busy line. The scheme that has met with universal adoption, however, is that the operator shall, when the tip of her calling plug touches the forward contact of the jack of a line that is already switched, receive a click in her telephone which will forbid her to insert the plug. The absence of this click, or silence in her telephone, informs her that she may safely make the connection. _Principle._ The means by which the operator receives or fails to receive this click, according to whether the line is busy or idle, vary widely, but so far as the writers are aware they all have one fundamental feature in common. The tip of the calling plug and the test contact of all of the multiple jacks of an idle line must be absolutely at the same potential before the test, so that no current will flow through the test circuit when the test is actually made. The test thimbles of all the jacks of a busy line must be at a different potential from the tip of the test plug so that a current will flow and a click result when the test is made. _Potential of Test Thimbles._ It has been found an easy matter to so arrange the contacts in the jacks of a multiple switchboard that whenever the line is idle the test thimbles of that line will be a certain potential, the same as that of all the unused calling plug tips. It has also been easy to so arrange these contacts that the insertion of a plug into any one of the jacks will, by virtue of the contacts established, change the potential of all the test thimbles of that line so that they will be at a different potential from that of the tips of the calling plugs. It has not been so easy, however, to provide that these conditions shall exist under all conditions of practice. A great many busy tests that looked well on paper have been found faulty in practice. As is always the case in such instances, this has been true because the people who considered the scheme on paper did not foresee all of the conditions that would arise in practice. Many busy-test systems will operate properly while everything connected with the switchboard and the lines served by it remains in proper order. But no such condition as this can be depended on in practice. Switchboards, no matter how perfectly made and no matter with how great care they may be installed and maintained, will get out of order. Telephone lines will become grounded or short-circuited or crossed or opened. Such conditions, in a faulty busy-test system, may result in a line that is really idle presenting a busy test, and thus barring the subscriber on that line from receiving calls from other lines just as completely as if his line were broken. On the other hand, faulty conditions either in the switchboard or in the line may make a line that is really busy, test idle, and thus result in the confusion of having two or more subscribers connected to the same line at the same time. _Busy-Test Faults._ To show how elusive some of the faults of a busy test may be, when considered on paper, it has come within the observation of the writers that a new busy-test system was thought well enough of by a group of experienced engineers to warrant its installation in a group of very large multiple switchboards, the cost of which amounted to hundreds of thousands of dollars, and yet when so installed it developed that a single short-circuited cord in a position would make the test inoperative on all the cords of that position--obviously an intolerable condition. Luckily the remedy was simple and easily applied. In a well-designed busy-test system there should be complete silence when the test is made of an idle line, and always a well-defined click when the test is made of a busy line. The test on busy lines should result in a uniform click regardless of length of lines or the condition of the apparatus. It does not suffice to have a little click for an idle line and a big click for a busy line, as practice has shown that this results in frequent errors on the part of the operators. Good operating requires that the tip of the calling plug be tapped against the test thimble several times in order to make sure of the state of the called line. In some multiple switchboards the arrangement has been such that the jacks of a line would test busy as soon as the subscriber on that line removed his receiver from its hook to make a call, as well as while any plug was in any jack of that line. The advocates of this added feature, in connection with the busy test, have claimed that the receiver, when removed from its hook in making a call, should make the line test busy and that a line should not be connected with when the subscriber's receiver was off its hook any more than it should be when it was already connected with at some other section of the switchboard. While it is true that a line may be properly termed busy when the subscriber has removed his receiver in order to make a call, it is not true that there is any real necessity for guarding against a connection with it while he is waiting for the operator to answer. Leaving the line unguarded for this brief period may result in the subscriber, who intended to make the call, having to defer his call until he has conversed with the party who is trying to reach him. This cannot be said to be a detriment to the service, however, since the second party gets the connection he desires much sooner than he otherwise would, and the first party may still make his first intended call as soon as he has disposed of the party who reached him while he was waiting for his own operator to answer. It may be said, therefore, in connection with this matter of making the line test busy as soon as a subscriber has removed his receiver from the hook, that it is not considered an essential, and in case of those switchboard systems which naturally work out that way it is not considered a disadvantage. =Field of Each Operator.= It was stated earlier in this chapter that as each section accommodated three operators, the total number of sections in a switchboard will be at least one-third the total number of required operators. This thought needs further development, for to stop at that statement is to arrive somewhat short of the truth. In order to do this it is necessary to consider the field in the multiple, reached by each operator. The section is of such size, or should be, that an operator seated in the center position of it may, without undue effort, reach all over the multiple. But the operator at the right-hand position cannot reach the extreme left portion of the multiple of that section, nor can the operator at the left reach the extreme right. How then may each operator reach a jack for every line? Remembering that the multiple jacks are arranged exactly the same in each section, each jack always occupying the same relative position, it is easy to see that while the operator at a right-hand position of a section cannot reach the left-hand third of the multiple in her own section, she may reach the left-hand third of the multiple in the section at her right, and this, together with the center and right-hand thirds of her own section, represents the entire number of lines. So it is with the left-hand operator at any section, she reaches two-thirds of all the lines in the multiple of her own section and one-third in that of the section at her left. _End Positions._ This makes it necessary to inquire about the operators at the end positions of the entire board. To provide for these the multiple is extended one-third of a section beyond them, so as to supply at the ends of the switchboard jacks for those lines which the end operators cannot reach on their own sections. Sometimes instead of adding these end sections to the multiple for the end operators, the same result is accomplished by using only the full and regular sections of the multiple, and leaving the end positions without operators' equipment, as well as without answering jacks, line signals, and cords and plugs, so that in reality the end operator is at the middle position of the end section. This, in our opinion, is the better practice, since it leaves the sections standard, and makes it easier to extend the switchboard in length, as it grows, by the mere addition of new sections without disturbing any of the old multiple. =Influence of Traffic.= We wish again to emphasize the fact that it is the traffic during the busiest time of day and not the number of lines that determine the size of a multiple switchboard so far as its length is concerned. The number of lines determines the size of the multiple in any one section, but it is the amount of traffic, the number of calls that are made in the busiest period, that determines the number of operators required, and thus the number of positions. Had this now very obvious fact been more fully realized in the past, some companies would be operating at less expense, and some manufacturers would have sold less expensive switchboards. The whole question as to the number of positions boils down to how many answering jacks and line signals may be placed at each operator's position without overburdening the operator with incoming traffic at the busy time of day. Obviously, some lines will call more frequently than others, and hence the proper number of answering jacks at the different positions will vary. Obviously, also, due to changes in the personnel of the subscribers, the rates of calling of different groups of lines will change from time to time, and this may necessitate a regrouping of the line signals and answering jacks on the positions; and changes in the personnel of the operators or in their skill also demand such regrouping. _Intermediate Frame._ The intermediate distributing frame is provided for this purpose, and will be more fully discussed in subsequent chapters. Suffice it to say here that the intermediate distributing frame permits the answering jacks and line signals to be shifted about among the operators' positions, so that each position will have just enough originating traffic to keep each of the operators economically busy during the busiest time of the day. CHAPTER XXV THE MAGNETO MULTIPLE SWITCHBOARD =Field of Utility.= The principles of the multiple switchboard set forth in the last chapter were all developed long before the common-battery system came into existence, and consequently all of the first multiple switchboards were of the magneto type. Although once very widely used, the magneto multiple switchboard has almost passed out of existence, since it has become almost universal practice to equip exchanges large enough to employ multiple boards with common-battery systems. Nevertheless there is a field for magneto multiple switchboards, and in this field it has recently been coming into increasing favor. In those towns equipped with magneto systems employing simple switchboards or transfer switchboards, and which require new switchboards by virtue of having outgrown or worn out their old ones, the magneto multiple switchboard is frequently found to best fit the requirements of economy and good practice. The reason for this is that by its use the magneto telephones already in service may be continued, no change being required outside of the central office. Furthermore, with the magneto multiple switchboard no provision need be made for a power plant, which, in towns of small size, is often an important consideration. Again, many companies operate over a considerable area, involving a collection of towns and hamlets. It may be that all of these towns except one are clearly of a size to demand magneto equipment and that magneto equipment is the standard throughout the entire territory of the company. If, however, one of the towns, by virtue of growth, demands a multiple switchboard, this condition affords an additional argument for the employment of the magneto multiple switchboard, since the same standards of equipment and construction may be maintained throughout the entire territory of the operating company, a manifest advantage. On the other hand, it may be said that the magneto multiple switchboard has no proper place in modern exchanges of considerable size--say, having upward of one thousand subscribers--at least under conditions found in the United States. Notwithstanding the obsolescence of the magneto multiple switchboard for large exchanges, a brief discussion of some of the early magneto multiple switchboards, and particularly of one of the large ones, is worth while, in that a consideration of the defects of those early efforts will give one a better understanding and appreciation of the modern multiple switchboard, and particularly of the modern multiple common-battery switchboard, the most highly organized of all the manual switching systems. Brief reference will, therefore, be made to the so-called series multiple switchboard, and then to the branch terminal multiple switchboard, which latter was the highest type of switchboard development at the time of the advent of common-battery working. [Illustration: Fig. 337. Series Magneto Multiple Switchboard] =Series-Multiple Board.= In Fig. 337 are shown the circuits of a series magneto multiple switchboard as developed by the engineers of the Western Electric Company during the eighties. As is usual, two subscribers' lines and a single cord circuit are shown. One side of each line passes directly from the subscriber's station to one side of the drop, and also branches off to the sleeve contact of each of the jacks. The other side of the line passes first to the tip spring of the first jack, thence to the anvil of that jack and to the tip spring of the next jack, and so on in series through all of the jacks belonging in that line to the other terminal of the drop coil. Normally, therefore, the drop is connected across the line ready to be responsive to the signal sent from the subscriber's generator. The cord circuit is of the two-conductor type, the plugs being provided with tip and sleeve contacts, the tips being connected by one of the flexible conductors through the proper ringing and listening key springs, and the sleeve being likewise connected through the other flexible conductor and the other springs of the ringing and listening keys. It is obvious that when any plug is inserted into a jack, the circuit of the line will be continued to the cord circuit and at the same time the line drop will be cut out of the circuit, because of the lifting of the tip spring of the jack from its anvil. Permanently connected between the sleeve side of the cord circuit and ground is a retardation coil _1_ and a battery. Another retardation coil _2_ is connected between the ground and a point on the operator's telephone circuit between the operator's head receiver and the secondary of her induction coil. These two retardation coils have to do with the busy test, the action of which is as follows: normally, or when a line is not switched at the central office, the test thimbles will all be at substantially ground potential, _i. e._, they are supposed to be. The point on the operator's receiver circuit which is grounded through the retardation coil _2_ will also be of ground potential because of that connection to ground. In order to test, the operator always has to throw her listening key _L.K._ into the listening position. She also has to touch the tip of the calling plug _P_c to a sleeve or jack of the line that is being tested. If, therefore, a test is made of an idle or non-busy line, the touching of the tip of the calling plug with the test thimble of that line will result in no flow of current through the operator's receiver, because there will be no difference of potential anywhere in the test circuit, which test circuit may be traced from the test thimble of the line under test to the tip of the calling plug, thence through the tip strand of the cord to the listening key, thence to the outer anvil of the listening key on that side, through the operator's receiver to ground through the impedance coil _2_. If, however, the line had already been switched at some other section by the insertion of either a calling or answering plug, all of the test thimbles of that line would have been raised to a potential above that of the ground, by virtue of the battery connected with the sleeve side of the cord circuit through the retardation coil _1_. If the operator had made a test of such a line, the tip of her testing plug would have found the thimble raised to the potential of the battery and, therefore, a flow of current would occur which would give her the busy click. The complete test circuit thus formed in testing a busy line would be from the ungrounded pole of the battery through the impedance coil _1_ associated with the cord that was already in connection with the line, thence to the sleeve strand of that cord to the sleeve of the jack at which the line was already switched, thence through that portion of the line circuit to which all of the sleeve contacts were connected, and therefore to the sleeve or test thimble of the jack at which the test is made, thence through the tip of the calling plug employed in making the test through the tip side of that cord circuit to the outer listening key contact of the operator making the test, and thence to ground through the operator's receiver and the impedance coil _2_. The resultant click would be an indication to the operator that the line was already in use and that, therefore, she must not make the connection. The condenser _3_ is associated with the operator's talking set and with the extra spring in the listening key _L.K._ in such a manner that when the listening key is thrown, the tip strand of the cord circuit is divided and the condenser included between them. This is for the purpose of preventing any potentials, which might exist on the line with which the answering plug _P_a was connected, from affecting the busy-test conditions. _Operation._ The operation of the system aside from the busy-test feature is just like that described in connection with the simple magneto switchboard. Assuming that the subscriber at Station _A_ makes the call, he turns his hand generator, which throws the drop on his line at the central office. The operator, seeing the signal, inserts the answering plug of one of her idle pairs of cords into the answering jack and throws her listening key _L.K._ This enables the operator to talk with the calling subscriber, and having found that he desires a connection with the line extending to Station _B_, she touches the tip of her calling plug to the multiple jack of that line that is within her reach, it being remembered that each one of the multiple jacks shown is on a different section. She leaves the listening key in the listening position when she does this. If the line is busy, the click will notify her that she must not make the connection, in which case she informs the calling subscriber that the line is busy and requests him to call again. If, however, she received no click, she would insert the calling plug into the jack, thus completing the connection between the two lines. She would then press the ringing key associated with the calling plug and that momentarily disconnects the calling plug from the answering plug and at the same time establishes connection between the ringing generator and the called line. The release of the ringing key again connects the calling and answering plugs and, therefore, connects the two subscribers' lines ready for conversation. All that is then necessary is that the called subscriber shall respond and remove his receiver from its hook, the calling subscriber already having done this. When the conversation is finished, both of the subscribers (if they remember it) will operate their ringing generators, which will throw the clearing-out drop as a signal to the operator for disconnection. If it should become necessary for the operator to ring back on the line of the calling subscriber, she may do so by pressing the ringing key associated with the calling plug. Frequently this multiple switchboard arrangement was used with grounded lines, in which case the single line wire extending from the subscriber's station to the switchboard was connected with the tip spring of the first jack, the circuit being continued in series through the jack to the drop and thence to ground through a high non-inductive resistance. _Defects._ This series multiple magneto system was used with a great many variations, and it had a good many defects. One of these defects was due to the necessary extending of one limb of the line through a large number of series contacts in the jacks. This is not to be desired in any case, but it was particularly objectionable in the early days before jacks had been developed to their present high state of perfection. A particle of dust or other insulating matter, lodging between the tip spring and its anvil in any one of the jacks, would leave the line open, thus disabling the line to incoming signals, and also for conversation in case the break happened to occur between the subscriber and the jack that was used in connecting with the line. Another defect due to the same cause was that the line through the switchboard was always unbalanced by the insertion of a plug, one limb of the line always extending clear through the switchboard to the drop and the other, when the plug was inserted, extending only part way through the switchboard and being cut off at the jack where the connection was made. The objection will be apparent when it is remembered that the wires in the line circuit connecting the multiple jacks are necessarily very closely bunched together and, therefore, there is very likely to be cross-talk between two adjacent lines unless the two limbs of each line are exactly balanced throughout their entire length. Again the busy-test conditions of this circuit were not ideal. The fact that the test rings of the line were connected permanently with the outside line circuit subjected these test rings to whatever potentials might exist on the outside lines, due to any causes whatever, such as a cross with some other wire; thus the test rings of an idle line might by some exterior cause be raised to such a potential that the line would test busy. It may be laid down as a fundamental principle in good multiple switchboard practice that the busy-test condition should be made independent of any conditions on the line circuit outside of the central office, and such is not the case in this circuit just described. [Illustration: CABLE RUN FROM INTERMEDIATE FRAME TO MULTIPLE Cortlandt Office, New York Telephone Co.] =Branch-Terminal Multiple Board.= The next important step in the development of the magneto multiple switchboard was that which produced the so-called branch-terminal board. This came into wide use in the various Bell operating companies before the advent of the common-battery systems. Its circuits and the principles of operation may be understood in connection with Fig. 338. In the branch-terminal system there are no series contacts in the jacks and no unbalancing of the line due to a cutting off of a portion of the line circuit when a connection was made with it. Furthermore, the test circuits were entirely local to the central office and were not likely to be affected by outside conditions on the line. This switchboard also added the feature of the automatic restoration of the drops, thus relieving the operator of the burden of doing that manually, and also permitting the drops to be mounted on a portion of the switchboard that was not available for the mounting of jacks, and thus permitting a greater capacity in jack equipment. [Illustration: Fig. 338. Branch-Terminal Magneto Multiple Switchboard] Each jack has five contacts, and the answering and multiple jacks are alike, both in respect to their construction and their connection with the line. The drops are the electrically self-restoring type shown in Fig. 263. The line circuits extended permanently from the subscriber's station to the line winding of the drop and the two limbs of the line branched off to the tip and sleeve contacts _1_ and _2_ respectively of each jack. Another pair of wires extended through the multiple parallel to the line wires and these branched off respectively to the contact springs _3_ and _4_ of each of the jacks. This pair of wires formed portions of the drop-restoring circuit, including the restoring coil _6_ and the battery _7_, as indicated. The test thimble _5_ of each of the jacks is connected permanently with the spring _3_ of the corresponding jack and, therefore, with the wire which connects through the restoring coil _6_ of the corresponding drop to ground through the battery _7_. The plugs were each provided with three contacts. Two of these were the usual tip and sleeve contacts connected with the two strands of the cord circuit. The third contact _8_ was not connected with any portion of the cord circuit, being merely an insulated contact on the plug adapted, when the plug was fully inserted, to connect together the springs _3_ and _4_. The cord circuit itself is readily understood from the drawing, having two features, however, which merit attention. One is the establishing of a grounded battery connection to the center portion of the winding of the receiver for the purposes of the busy test, and the other is the provision of a restoring coil and restoring circuit for the clearing-out drop, this circuit being closed by an additional contact on the listening key so as to restore the clearing-out drop whenever the listening key was operated. _Operation._ An understanding of the operation of this system is easy. The turning of the subscriber's generator, when the line was in its normal condition, caused the display of the line signal. The insertion of the answering plug, in response to this call, did three things: (1) It extended the line circuit to the tip and sleeve strand of the cord circuit. (2) It energized the restoring coil _6_ of the drop by establishing the circuit from the contact spring _3_ through the plug contact _8_ to the other contact spring _4_, thus completing the circuit between the two normally open auxiliary wires. (3) The connecting of the springs _3_ and _4_ established a connection from ground to the test thimbles of all the jacks on a line, the spring _4_ being always grounded and the spring _3_ being always connected to the test thimble _5_. It is to be noted that on idle lines the test rings are always at the same potential as the ungrounded pole of the battery _7_, being connected thereto through the winding _6_ of the restoring coil. On all busy lines, however, the test rings are dead grounded through the contact _8_ of the plug that is connected with the line. The tip of the testing plug at the time of making a test will also be at the same potential as that of the ungrounded pole of the battery _7_, since this pole of the battery _7_ is always connected to the center portion of the operator's receiver winding, and when the listening key is thrown the tip of the calling plug is connected therewith and is at the same potential. When, therefore, the operator touches the tip of the calling plug to the test thimble of an idle line, she will get no click, since the tip of the plug and the test thimble will be at the same potential. If, however, the line has already been switched at another section of the board, there will be a difference of potential, because the test thimble will be grounded, and the circuit, through which the current which causes the click flows, may be traced from the ungrounded pole of the battery _7_ to the center portion of the operator's receiver, thence through one-half of the winding to the tip of the calling plug, thence to the test thimble of the jack under test, thence to the spring _3_ of the jack on another section at which the connection exists, through the contact _8_ on the plug of that jack to the spring _4_, and thence to ground and back to the other terminal of the battery _7_. _Magnet Windings._ Coils of the line and clearing-out drops by which these drops are thrown, are wound to such high resistance and impedance as to make it proper to leave them permanently bridged across the talking circuit. The necessity for cutting them out is, therefore, done away with, with a consequent avoidance, in the case of the line drops, of the provision of series contacts in the jacks. _Arrangement of Apparatus._ In boards of this type the line and clearing-out drops were mounted in the extreme upper portion of the switchboard face so as to be within the range of vision of the operator, but yet out of her reach. Therefore, the whole face of the board that was within the limit of the operator's reach was available for the answering and multiple jacks. A front view of a little over one of the sections of the switchboard, involving three complete operator's positions, is shown in Fig. 339, which is a portion of the switchboard installed by the Western Electric Company in one of the large exchanges in Paris, France. (This has recently been replaced by a common-battery multiple board.) In this the line drops may be seen at the extreme top of the face of the switchboard, and immediately beneath these the clearing-out drops. Beneath these are the multiple jacks arranged in banks of one hundred, each hundred consisting of five strips of twenty. At the extreme lower portion of the jack space are shown the answering jacks and beneath these on the horizontal shelf, the plugs and keys. These jacks were mounted on 1/2-inch centers, both vertically and horizontally and each section had in multiple 90 banks of 100 each, making 9,000 in all. Subsequent practice has shown that this involves too large a reach for the operators and that, therefore, 9,000 is too large a number of jacks to place on one section if the jacks are not spaced closer than on 1/2-inch centers. With the jack involving as many parts as that required by this branch terminal system, it was hardly feasible to make them smaller than this without sacrificing their durability, and one of the important features of the common-battery multiple system which has supplanted this branch-terminal magneto system is that the jacks are of such a simple nature as to lend themselves to mounting on 3/8-inch centers, and in some cases on 3/10-inch centers. [Illustration: Fig. 339. Face of Magneto Multiple Switchboard] =Modern Magneto Multiple Board.= Coming now to a consideration of modern magneto multiple switchboards, and bearing in mind that such boards are to be found in modern practice only in comparatively small installations and then only under rather peculiar conditions, as already set forth, we will consider the switchboard of the Monarch Telephone Manufacturing Company as typical of good practice in this respect. [Illustration: Fig. 340. Monarch Magneto Multiple Switchboard Circuits] _Line Circuit._ The line and cord circuits of the Monarch system are shown in Fig. 340. It will be seen that each jack has in all five contacts, numbered from _1_ to _5_ respectively, of which _1_ and _4_ are the springs which register with the tip and ring contacts of the plug and through which the talking circuit is continued, while _2_ and _3_ are series contacts for cutting off the line drop when a plug is inserted, and _5_ is the test contact or thimble adapted to register with the sleeve contact on the plug when the plug is fully inserted. The line circuit through the drop may be traced normally from one side of the line through the drop coil, thence through all of the pairs of springs _2_ and _3_ in the jacks of that line, and thence to spring _1_ of the last jack, this spring always being strapped to the spring _2_ in the last jack, and thence to the other side of the line. All the ring springs _1_ are permanently tapped on to one side of the line, and all of the tip springs _4_ are permanently tapped to the other side of the line. This system may, therefore, properly be called a branch-terminal system. It is seen that as soon as a plug is inserted into any of the jacks, the circuit through the drop will be broken by the opening of the springs _2_ and _3_ in that jack. The drop shown immediately above the answering jack is so associated mechanically with that jack as to be mechanically self-restored when the answering plug is inserted into the answering jack in response to a call. The arrangement in this respect is the same as that shown in Fig. 259, illustrating the Monarch combined drop and jack. _Cord Circuit._ The cord circuit needs little explanation. The tip and ring strands are the ones which carry the talking current and across these is bridged the double-wound clearing-out drop, a condenser being included in series in the tip strand between the two drop windings in the manner already explained in connection with Fig. 284. The third or sleeve strand of the cord is continuous from plug to plug, and between it and the ground there is permanently connected a retardation coil. _Test._ The test is dependent on the presence or absence of a path to ground from the test thimbles through some retardation coil associated with a cord circuit. Obviously, in the case of an idle line there will be no path to ground from the test thimbles, since normally they are merely connected to each other and are insulated from everything else. When, however, a plug is inserted into a multiple or answering jack, the test thimbles of that line are connected to ground through the retardation coil associated with the third strand of the plug used in making the connection. When the operator applies the tip of the calling plug to a test contact of a multiple jack there will be no path to ground afforded if the line is idle, while if it is busy the potential of the tip of the test plug will cause a current to flow to ground through the impedance coil associated with the plug used in making the connection. This will be made clearer by tracing the test circuit. With the listening key thrown this may be traced from the live side of the battery through the retardation coil _6_, which is common to an operator's position, thence through the tip side of the listening key to the tip conductor of the calling cord, and thence to the tip of the calling plug and the thimble of the jack under test. If the line is idle there will be no path to ground from this point and no click will result, but if the line is busy, current will flow from the tip of the test plug to the thimble of the jack tested, thence by the test wire in the multiple to the thimble of the jack at which a connection already exists, and thence to ground through the third strand of the cord used in making that connection and the impedance coil associated therewith. The current which flows in this test circuit changes momentarily the potential of the tip side of the operator's telephone circuit, thus unbalancing her talking circuit and causing a click. [Illustration: Fig. 341. Magneto Multiple Switchboard] If this test system were used in a very large board where the multiple would extend through a great many sections, there would be some liability of a false test due to the static capacity of the test contacts and the test wire running through the multiple. For small boards, however, where the multiple is short, this system has proven reliable. A multiple magneto switchboard employing the form of circuits just described is shown in Fig. 341. This switchboard consists of three sections of two positions each. The combined answering jacks and drops may be seen at the lower part of the face of the switchboard and occupying somewhat over one-half of the jack and drop space. The multiple jacks are above the answering jacks and drops and it may be noted that the same arrangement and number of these jacks is repeated in each section. This switchboard may be extended by adding more sections and increasing the multiple in those already installed to serve 1,600 lines. _Assembly._ In connection with the assembly of these magneto multiple switchboards, as installed by the Monarch Company, Fig. 342 shows the details of the cord rack at the back of the board. It shows how the ends of the switchboard cords opposite to the ends that are fastened to the plugs are connected permanently to terminals on the cord rack, at which point the flexible conductors are brought out to terminal clips or binding posts, to which the wires leading from the other portions of the cord circuit are led. In order to relieve the conductors in the cords from strain, the outer braiding of the cord at the rack end is usually extended to form what is called a _strain cord_, and this attached to an eyelet under the cord rack, so that the weight of the cord and the cord weights will be borne by the braiding rather than by the conductors. This leaves the insulated conductors extending from the ends of the cords free to hang loose without strain and be connected to the terminals as shown. This method of connecting cords, with variations in form and detail, is practically universal in all types of switchboards. [Illustration: Fig. 342. Cord-Rack Connectors] A detail of the assembly of the drops and jacks in such a switchboard is shown in Fig. 343. The single pair of clearing-out drops is mounted in the lower part of the vertical face of the switchboard just above the space occupied by the plug shelf. Vertical stile strips extend above the clearing-out drop space for supporting the drops and jacks. A single row of 10 answering jacks and the corresponding line drops are shown in place. Above these there would be placed, in the completely assembled board, the other answering jacks and line signals that were to occupy this panel, and above these the strips of multiple jacks. The rearwardly projecting pins from the stile strips are for the support of the multiple jack strips, these pins supporting the strips horizontally by suitable multiple clips at the ends of the jack strips; the jack strips being fastened from the rear by means of nuts engaging the screw threads on these pins. This method of supporting drops and jacks is one that is equally adaptable for use in other forms of boards, such as the simple magneto switchboard. [Illustration: Fig. 343. Drop and Jack Mounting] [Illustration: Fig. 344. Keyboard Wiring] In Fig. 344 is shown a detail photograph of the key shelf wiring in one of these Monarch magneto switchboards. In this the under side of the keys is shown, the key shelf being raised on its hinge for that purpose. The cable, containing all of the insulated wires leading to these keys, enters the space under the key shelf at the extreme left and from the rear. It then passes to the right of this space where a "knee" is formed, after which the cable is securely strapped to the under side of the key shelf. By this construction sufficient flexibility is provided for in the cable to permit the raising and lowering of the key shelf, the long reach of the cable between the "knee" and the point of entry at the left serving as a torsion member, so that the raising of the shelf will give the cable a slight twist rather than bend it at a sharp angle. CHAPTER XXVI THE COMMON-BATTERY MULTIPLE SWITCHBOARD =Western Electric No. 1 Relay Board.= The common-battery multiple switchboard differs from the simple or non-multiple common-battery switchboard mainly in the provision of multiple jacks and in the added features which are involved in the provision for a busy test. The principles of signaling and of supplying current to the subscribers for talking are the same as in the non-multiple common-battery board. For purposes of illustrating the practical workings of the common-battery multiple switchboard, we will take the standard form of the Western Electric Company, choosing this only because it is the standard with nearly all the Bell operating companies throughout the United States. [Illustration: Fig. 345. Line Circuit Western Electric No. 1. Board] _Line Circuit._ We will first consider the line circuit in simplified form, as shown in Fig. 345. At the left in this figure the common-battery circuit is shown at the subscriber's station, and at the right the central-office apparatus is indicated so far as equipment of a single line is concerned. In this simplified diagram no attempt has been made to show the relative positions of the various parts, these having been grouped in this figure in such a way as to give as clear and simple an idea as possible of the circuit arrangements. It is seen at a glance that this is a branch terminal board, the three contacts of each jack being connected by separate taps or legs to three wires running throughout the length of the board, these three wires being individual to the jacks of one line. On this account this line circuit is commonly referred to as a three-wire circuit. By the same considerations it will be seen that the switchboard line circuit of the branch-terminal multiple magneto system, shown in Fig. 338, would be called a four-wire circuit. It will be shown later that other multiple switchboards in wide use have a still further reduction in the number of wires running through the jacks, or through the multiple as it is called, such being referred to as two-wire switchboards. The two limbs of the line which extend from the subscriber's circuit, beside being connected by taps to the tip and sleeve contacts of the jack respectively, connect with the two back contacts of a cut-off relay, and when this relay is in its normal or unenergized condition, these two limbs of the line are continued through the windings of the line relay and thence one to the ungrounded or negative side of the common-battery and the other to the grounded side. The subscriber's station circuit being normally open, no current flows through the line, but when the subscriber removes his receiver for the purpose of making a call the line circuit is completed and current flows through the coil of the line relay, thus energizing that relay and causing it to complete the circuit of the line lamp. The cut-off relay plays no part in the operation of the subscriber's calling, but merely leaves the circuit of the line connected through to the calling relay and battery. The coil of the cut-off relay is connected to ground on one side and on the other side to the third wire running through the switchboard multiple and which is tapped off to each of the test rings on the jacks. As will be shown later, when the operator plugs into the jack of a line, such a connection is established that the test ring of that jack will be connected to the live or negative pole of the common battery, which will cause current to flow through the coil of the cut-off relay, which will then operate to _cut off_ both of the limbs of the line from their normal connection with ground and the battery and the line relay. Hence the name _cut-off relay_. The use of the cut-off relay to sever the calling apparatus from the line at all times when the line is switched serves to make possible a very much simpler jack than would otherwise be required, as will be obvious to anyone who tries to design a common-battery multiple system without a cut-off relay. The additional complication introduced by the cut-off relay is more than offset by the saving in complexity of the jacks. It is desirable, on account of the great number of jacks necessarily employed in a multiple switchboard, that the jacks be of the simplest possible construction, thus reducing to a minimum their first cost and making them much less likely to get out of order. _Cord Circuit._ The cord circuit of the Western Electric standard multiple common-battery switchboard is shown in Fig. 346. This cord circuit involves the use of three strands in the flexible cords of both the calling and the answering plugs. Two of these are the ordinary tip and ring conductors over which speech is transmitted to the connected subscriber's wire. The third, the sleeve strand, carries the supervisory lamps and has associated with it other apparatus for the control of these lamps and of the test circuit. [Illustration: Fig. 346. Cord Circuit Western Electric No. 1 Board] The system of battery feed is the well-known split repeating-coil arrangement already discussed. The tip strand runs straight through to the repeating coil, while the ring strand contains, in each case, the winding of the supervisory relay corresponding to either the calling or the answering plug. In order that the presence in the talking circuit of a magnet winding possessing considerable impedance may not interfere with the talking efficiency, each of these supervisory relay windings is shunted by a non-inductive resistance. In practice the supervisory relay windings have each a resistance of about 20 ohms and the shunt around them each a resistance of about 31 ohms. In the third strand of each cord is placed a 12-volt supervisory lamp, and in series with it a resistance of about 80 ohms. Each supervisory relay is adapted, when energized, to close a 40-ohm shunt about its supervisory lamp. The arrangement and proportion of these resistances is such that when a plug is inserted into the jack of a line the lamp will receive current from a circuit traced from the negative pole of the battery in the center of the cord circuit through the lamp and the 80-ohm series resistance, through the third strand of the cord to the test thimble of the jack, and thence to the positive or grounded pole of the battery through the third conductor in the multiple and the winding of the cut-off relay. This current always flows as long as the plug is inserted, and it is just sufficient to illuminate the lamp when the supervisory relay armature is not attracted. When, however, the supervisory relay armature is attracted, the shunting of the lamp by the 40-ohm resistance cuts down the current to such a degree as to prevent the illumination of the lamp, although some current still flows through it. The usual ringing and listening key is associated with the calling plug, and in some cases a ring-back key is associated with the answering plug, but this is not standard practice. _Operation._ The operation of this cord circuit in conjunction with the line circuit of Fig. 345 may best be understood by reference to Fig. 347. This figure employs a little different arrangement of the line circuit in order more clearly to indicate how the two lines may be connected by a cord; a study of the two line circuits, however, will show that they are identical in actual connections. It is to be remembered that all of the battery symbols shown in this figure represent in reality the same battery, separate symbols being shown for greater simplicity in circuit connections. We will assume the subscriber at Station _A_ calls for the subscriber at Station _B_. The operation of the line relay and the consequent lighting of the line lamp, and also the operation of the pilot relay will be obvious from what has been stated. The response of the operator by inserting the answering plug into the answering jack, and the throwing of her listening key so as to bridge her talking circuit across the cord in order to place herself in communication with the subscriber, is also obvious. The insertion of the answering plug into the answering jack completed the circuit through the third strand of the cord and the winding of the cut-off relay of the calling line, and this accomplishes three desirable results. The circuit so completed may be traced from the negative or ungrounded side of the battery to the center portion of the cord circuit, thence through the supervisory lamp _1_, resistance _2_, to the third conductor on the plug, test thimble on the jack, thence through the winding of the cut-off relay to ground, which forms the other terminal of the battery. The results accomplished by the closing of this circuit are: first, the energizing of the cut-off relay to cut off the signaling portion of the line; second, the flowing of current through the lamp that is almost sufficient to illuminate it, but not quite so because of the closure of the shunt about it, for the reason that will be described; third, the raising of the potential of all the contact thimbles on the jacks from zero to a potential different from that of the ground and equal in amount to the fall of potential through the winding of the cut-off relay. A condition is thus established at the test rings such that some other operator at some other section in testing the line will find it busy and will not connect with it. [Illustration: Fig. 347. Western Electric No. 1 Board] The reason why the lamp _1_, connected with the answering plug, was not lighted was that the supervisory relay _3_, associated with the answering plug, became energized when the operator plugged in, due to the flow of current from the battery through the calling subscriber's talking apparatus, this flow of current being permitted by the removal of the calling subscriber's receiver from its hook. The energizing of this relay magnet by causing the attraction of its armature, closed the shunt about the lamp _1_, which shunt contains the 40-ohm resistance _4_, and thus prevents the lamp from receiving enough current to illuminate it. Obviously, as soon as the calling subscriber replaces his receiver on its hook, the supervisory relay _3_ will be de-energized, the shunt around the lamp will be broken, and the lamp will be illuminated to indicate to the operator the fact that the subscriber with whose line her calling plug is connected has replaced his receiver on its hook. _Testing--Called Line Idle._ Having now shown how the operator connects with the calling subscriber's line and how that line automatically becomes guarded as soon as it is connected with, so that no other operator will connect with it, we will discuss how the operator tests the called line and subsequently connects with that line, if it is found proper to do so. If, on making the test with one of the multiple jacks of the line leading to Station _B_, that line is idle and free to be connected with, its test rings will all be at zero potential because of the fact that they are connected with ground through the cut-off relay winding with no source of current connected with them. The tip of the calling plug will also be at zero potential in making this test, because it is connected to ground through the tip side of the calling-plug circuit and one winding of the cord-circuit repeating coil. As a result no flow of current will occur, the operator will receive no click, and she will know that she is free to connect with the line. As soon as she does so, by inserting the plug, the third strand of the cord will be connected with the test thimble of the calling line and the resulting flow of current will bring about three results, two of which are the same, and one of which is slightly different from those described as resulting from the insertion of the answering plug into the jack of the calling line. First, the cut-off relay will be operated and cut off the line signaling apparatus from the called line; second, a flow of current will result through the calling supervisory lamp _5_, which in this case will be sufficient to illuminate that lamp for the reason that the called subscriber has not yet responded, the calling supervisory relay _6_ has, therefore, not yet been energized, and the lamp has not, therefore, been shunted by its associated resistance _7_; third, the test thimbles of the called line will be raised to a potential above that of the earth, and thus the line will be guarded against connection at another section of the switchboard. As soon as the called subscriber responds to the ringing current sent out by the operator, current will flow over the cord circuit and over his line through his transmitter. This will cause the calling supervisory relay to be energized and the calling lamp to be extinguished. Both lamps _1_ and _5_ remain extinguished as long as the connected subscribers are in conversation, but as soon as either one of them hangs up his receiver the corresponding lamp will be lighted, due to the de-energization of the supervisory relay and the breaking of the shunt around the lamp. The lighting of both lamps associated with a cord circuit is a signal to the operator for disconnection. [Illustration: TERMINAL ROOM IN MEDIUM-SIZED MANUAL OFFICE Relay Rack at Right. This Employs the Kellogg Parallel Arrangement of Frames.] _Testing--Called Line Busy._ If we now assume that the called line was already busy, by virtue of being connected with at another section, the test rings of that line would accordingly all be raised to a potential above that of the earth. As a result, when the operator applied the tip of her calling plug to a test thimble on that line, current would flow from this test thimble through the tip of the calling plug and tip strand of the cord and through one winding of the cord-circuit repeating coil to ground. This would cause a slight raising of potential of the entire tip side of the cord circuit and a consequent momentary flow of current through the secondary of the operator's circuit bridged across the cord circuit at that time. _Operator's Circuit Details._ The details of the operator's talking circuit shown in Fig. 347 deserve some attention. The battery supply to the operator's transmitter is through an impedance coil _9_. The condenser _12_ is bridged around the transmitter and the two primary windings _10_ and _11_, which windings are in parallel so as to afford a local circuit for the passage of fluctuating currents set up by the transmitter. The two primary windings _10_ and _11_ are on separate induction coils, the secondary windings _13_ and _14_ being, therefore, on separate cores. The winding _15_, in circuit with the secondary winding _14_ and the receiver, is a non-inductive winding and is supposed to have a resistance about equal to the effective resistance to fluctuating currents of a subscriber's line of average length. Owing to the respective directions of the primary and secondary windings _10_ and _11_, _13_ and _14_, the result is that the outgoing currents set up by the operator's transmitter are largely neutralized in the operator's receiver. Incoming currents from either of the connected subscribers, however, pass, in the main, through the secondary coil _13_ and the operator's receiver, rather than through the shunt path formed by the secondary _14_, and the non-inductive resistance _15_. This is known as an "anti-side tone" arrangement, and its object is to prevent the operator from receiving her own voice transmission so loudly as to make her ear insensitive to the feebler voice currents coming in from the subscribers. _Order-Wire Circuits._ The two keys _16_ and _17_, shown in connection with the operator's talking circuit in Fig. 347, play no part in the regular operation of connecting two local lines, as described above. They are order-wire keys, and the circuits with which they connect lead to the telephone sets of other operators at distant central offices, and by pressing either one of these keys the operator is enabled to place herself in communication over these so-called order-wire circuits with such other operators. The function and mode of operation of these order-wire circuits will be described in the next chapter, wherein inter-office connections will be discussed. _Wiring of Line Circuit._ The line circuits shown in Figs. 345 and 347 are, as stated, simplified to facilitate understanding, although the connections shown are those which actually exist. The more complete wiring of a single line circuit is shown in Fig. 348. The line wires are shown entering at the left. They pass immediately, upon entering the central office, through the main distributing frame, the functions and construction of which will be considered in detail in a subsequent chapter. The dotted portions of the circuit shown in connection with this main distributing frame indicate the path from the terminals on one side of the frame to those on the other through so-called jumper wires. The two limbs of the line then pass to terminals _1_ and _2_ on one side of the so-called intermediate distributing frame. Here the circuit of each limb of the line divides, passing, on the one hand, to the tip and sleeve springs of all the multiple jacks belonging to that line; and, on the other hand, through the jumper wires indicated by dotted lines on the intermediate distributing frame, and thence to the tip and ring contacts of the answering jack. A consideration of this connection will show that the actual electrical connections so far as already described are exactly those of Figs. 345 and 347, although those figures omitted the main and intermediate distributing frames. Only two limbs of the line are involved in the main frame. In the intermediate frame the test wire running through the multiple is also involved. This test wire, it will be seen, leads from the test thimbles of all the multiple jacks to the terminal _3_ on the intermediate frame, thence through the jumper wire to the terminal _6_ of this frame, and to the test thimble of the answering jack. Here again the electrical connections are exactly those represented in Figs. 345 and 347, although those figures do not show the intermediate frame. The two terminals _4_ and _5_ of the intermediate frame, besides being connected to the tip and sleeve springs of the answering jack, are connected to the contacts of the cut-off relay, and thence through the coils of the line relay to ground on one side and to battery on the other. Thus the line relay and battery are normally included in the circuit of the line. The contact _6_ on the intermediate distributing frame, besides being connected to the test thimble of all the jacks, is connected through the coil of the cut-off relay to ground, thus establishing a path by which current is supplied to the cut-off relay when connection is made to the line at any jack. There is another contact _7_ on the intermediate distributing frame which merely forms a terminal for joining one side of the line lamp to the back contact of the line relay. _Functions of Distributing Frames._ Since the line circuit thus far described in connection with Fig. 348 is exactly the same as that of Fig. 345 in its electrical connections, it becomes obvious that the main and intermediate distributing frames play no part in the operation of the circuit any more than a binding post of a telephone plays a part in its operation. These frames carry terminals for facilitating the connection of the various wires in the line circuit and, as will be shown later, for facilitating certain changes in the line connection. [Illustration: Fig. 348. Line Circuit No. 1 Board] Remembering that the dotted lines in Fig. 348 indicate jumper wires of the main and intermediate distributing frames, and that these are in the nature of temporary or readily changeable connections, and that the full lines, whether heavy or light, are permanent connections not readily changeable, it will be seen that the wires leading through the multiple jacks of a certain line are permanently associated with each other, and with certain terminals on the main distributing frame and certain other terminals on the intermediate distributing frame. It will also be seen that the line lamp and the answering jack, together with the cut-off relay and line relay, are permanently associated with each other and with another group of terminals _4_, _5_, _6_, and _7_ on the intermediate distributing frame. It will also be apparent that by changing the jumper wires on the main frame, any outside line may be connected with any different set of line switchboard equipment, and also that by making changes in the jumper wires on the intermediate frame, any given answering jack and line lamp with its associated line cut-off relay may be associated with any set of multiple jacks. _Pilot Signals._ In a portion of the circuit leading from the battery that is common to a group of line lamps is the winding of the pilot relay, which is common to this group of line lamps. This controls, as already described, the circuit of the pilot lamp common to the same group of line lamps. In addition, a night-bell circuit is sometimes provided, this usually being in the form of an ordinary polarized ringer, the circuit of which is controlled by a night-bell relay common to the entire office. Normally, this relay is shunted out of the circuit of the common portion of the lead to the pilot relay contacts by the key _8_, but when the key _8_ is opened all current that is fed to the pilot lamps passes through the night-bell relay, and thus, whenever any pilot lamp is lighted, the night-bell relay will attract its armature and thus close the circuit of the calling generator through the night bell. A study of this figure will make clear to the student how the portions of the circuit that are individual to the line are associated with such things as the battery, that are common to the entire office, and such as the pilot relay and lamp, that are common to a group of lines terminating in one position. _Modified Relay Windings._ In some cases, the line relay instead of being double wound, as shown, is made with a single winding, this winding being normally included between the ring side of the cut-off relay and the battery, the tip side of the cut-off relay being run direct to ground. The present practice of the Western Electric Company is towards the double-wound relay, however, and that is considered standard in all of their large No. 1 multiple boards, except where the customer, owing to special reasons, demands a single wound relay on the ring side of the line. The prime reason for the two-winding line relay is the lessened click in the calling-subscriber's receiver which occurs when the operator answers. All line relays prior to 1902 were single-wound, but after that they were made double and used some turns of resistance wire to limit the normal calling current. _Relay Mounting._ In the standard No. 1 relay board of the Western Electric Company and, in fact, in nearly all common-battery multiple boards that are manufactured by other companies, the line and cut-off relays are mounted on separate racks outside the switchboard room and adjacent to the main and intermediate distributing frames, the wiring being extended from the relays to the jacks and lamps on the switchboard proper by means of suitable cables. The Western Electric Company has recently instituted a departure from this practice in the case of some of their smaller No. 1 switchboard installations. Where it is thought that the ultimate capacity required by the board will not be above 3,000 lines, the relay rack is dispensed with and all of the line and cut-off relays, as well as the supervisory relays, are mounted in the rear of the switchboard frame. For this purpose the line and cut-off relays are specially made with the view to securing the utmost compactness. In still other cases, in switchboards of relatively small ultimate capacity, they use this small line and cut-off relay mounted on a separate relay rack, in which case the board is the standard No. 1 board except for the type of relays. In all of these modifications of the No. 1 board adapted for the use of the smaller and cheaper relays, the line relay has but a single winding, the small size of the relay winding not lending itself readily to double winding with the added necessary coil terminals. _Capacity Range._ The No. 1 Western Electric board is made in standard sizes up to an ultimate capacity of 9,600 lines. For all capacities above 4,900 lines, a 3/8-inch jack, vertical and horizontal face dimensions, is employed. For this capacity the smaller types of cut-off and line relays are not employed. Up to ultimate capacities of 4,900 lines, 1/2-inch jacks are employed, and either the small or the large relays mounted on a separate rack are available. Up to 3,000 lines ultimate capacity, the 1/2-inch jack is employed, and either the small or the large cut-off and line relays are available, but in case the small type is used the purchaser has the option of mounting them on a separate relay rack, as in ordinary practice, or mounting them in the switchboard cabinet and dispensing with the relay rack. =Western Electric No. 10 Board.= The No. 1 common-battery multiple switchboard, regardless of its size and type of arrangement of line and cut-off relays, involves two relays for each line, the line relay energized by the taking of the receiver off its hook, and the cut-off relay energized by the act of the operator on plugging in and serving to remove the line relay from the circuit whenever and as long as a plug is inserted into any jack of the line. This seems to involve a considerable expense in relays, but this, as has been stated, is warranted by the greater simplicity in jacks which the use of the cut-off relay makes possible. In addition to this expense of investment in the line and cut-off relays, the amount of current required to hold up the cut-off relays during conversations foots up to a considerable item of expense, particularly as the system of supervisory signals is one in which the supervisory lamp takes current not only while burning, but its circuit takes even more current when the lamp is extinguished during the time of a connection. For all of these reasons, and some other minor ones, it was deemed expedient by the engineers of the Western Electric Company to design a common-battery multiple switchboard for small and medium-sized exchanges in which certain sacrifices might be made to the end of accomplishing certain savings. The result has been a type of switchboard, designated the No. 10, which may be found in a number of Bell exchanges, it being considered particularly adaptable to installations of from 500 to 3,000 lines. Although this board has been subject to a good deal of adverse criticism, and although it seems probable that even for the cheaper boards the No. 1 type with some of the modifications just described will eventually supersede this No. 10 board, yet the present extent of use of the No. 10 board and the instructive features which its type displays warrant its discussion here. _Circuits._ The circuits of this switchboard are shown in Fig. 349, this indicating two-line circuits and a connecting cord circuit, together with the auxiliary apparatus employed in connection with the operator's telephone circuit, the pilot and night alarm circuits. The most noticeable feature is that cut-off jacks are employed, the circuit of the line normally extending through the sets of jack springs in the multiple, and answering jacks to the line relay and battery on one side of the line, and to ground on the other side. Obviously, the additional complexity of the jack saves the use of a cut-off relay and the relay equipment of each line consists, therefore, of but a single line relay, which controls the lamp in an obvious manner. [Illustration: Fig. 349. Western Electric No. 10 Board] The cord circuit is of the three-conductor type, the two talking strands extending to the usual split repeating-coil arrangement, and battery current for talking purposes being fed through these windings as in the standard No. 1 board. The supervisory relay is included in the ring strand of the cord circuit and is shunted by a non-inductive resistance, so that its impedance will not interfere with the talking currents. The armature of the supervisory relay closes the lamp contact on its back stroke, so that the lamp is always held extinguished when the relay is energized. The supervisory lamp is included in a connection between the back contact of the supervisory relay and ground, this connection including the central-office battery. As a result, the illumination of the supervisory lamp is impossible until a plug has been inserted into a jack, in which case, assuming the supervisory relay to be de-energized, the lamp circuit is completed through the wire connecting all of the test thimbles and the resistance permanently bridged to ground from that wire. _Test._ For purposes of the test it is evident that the test rings of an idle line are always at ground potential, due to their connection to ground through the resistance coil. It is also evident that the tip of an unused calling plug will always be at ground potential and, therefore, that the testing of an idle line will result in no click in the operator's receiver. When a line is switched, however, the potential of all the test rings will be raised due to their being connected with the live pole of the battery through the third strand of the cord. When the operator in testing touches the test contact of the jack of a busy line, a current will, therefore, flow from this test contact to the tip strand of the cord and thence to ground through one of the repeating coil windings. The potential of the tip side of the cord will, therefore, be momentarily altered, and this will result in a click in the operator's receiver bridged across the cord circuit at the time. The details of the operator's cord circuit and of the pilot lamp and night alarm circuits will be clear from the diagram. _Operation._ A brief summary of the operation of this system is as follows: The subscriber removes his receiver from its hook, thus drawing up the armature of the line relay and lighting his line lamp. The operator answers. The line lamp is extinguished by the falling back of the line-relay armature, due to the breaking of the relay circuit at the jack contacts. The subscriber then receives current for his transmitter through the cord-circuit battery connections. The supervisory relay connected with the answering cord is not lighted, because, although the lamp-circuit connection is completed at the jack, the supervisory relay is operated to hold the lamp circuit open. Conversation ensues between the operator and the subscriber, after which the operator tests the line called for with the tip of the calling plug of the pair used in answering. If the called line is not busy, no click will ensue, because both the tested ring and the calling plug are at the same potential. Finding no click, the operator will insert the plug and ring by means of the ringing key. When the operator plugs in, the supervisory lamp, associated with the calling plug, becomes lighted because the circuit is completed at the jack and the supervisory relay remains de-energized, since the line circuit is open at the subscriber's station. When the called subscriber responds, the calling supervisory lamp goes out because of the energization of the supervisory relay. Both lamps remain out during the conversation, but when either subscriber hangs up, the corresponding supervisory lamp will be lighted because of the falling back of the supervisory relay armature. If the called line is busy, a click will be heard, for the reason described, and the operator will so inform the calling subscriber. It goes without saying, that in any multiple-switchboard system a plug may be found in the actual multiple jack that is reached for, in which case, although no test will be made, the busy condition will be reported back to the calling subscriber. _Economy._ It has been the belief of the Western Electric engineers that a real economy is accomplished in this type of board by the saving in relay equipment. It is, of course, apparent at a glance that with a switchboard long enough and of sections enough, the cost of extra jack springs and their platinum contacts must become great enough to offset the saving accomplished by omitting the cut-off relay. This makes it apparent that if there is any economy in this type of multiple switchboard, it must be found in the very small boards where there are but few jacks per line and where the extra cost of the cut-off jack is not enough to offset the extra cost of an added relay. It is the growing belief, however, among engineers, that the multiple switchboard must be very small indeed in order that the added complexity of the cut-off jacks and wiring may be able to save anything over the two-relay type of line; and it is believed that where economy is necessary in small boards, it may be best effected by employing cheaper and more compact forms of relays and mounting them, if necessary, directly in the switchboard cabinet. NOTE. These two standard types of common-battery multiple switchboards of the Western Electric Company represent the development through long years of careful work on the part of the Western Electric and Bell engineers, credit being particularly due to Scribner, McBerty, and McQuarrie of the Western Electric Company, and Hayes of the American Telephone and Telegraph Company. =Kellogg Two-Wire Multiple Board.= The simplicity in the jacks permitted by the use of the cut-off relay in the Western Electric common-battery multiple switchboard for larger exchanges was carried a step further by Dunbar and Miller in the development of the so-called two-wire common-battery multiple switchboard, which for many years has been the standard of the Kellogg Switchboard and Supply Company. The particular condition which led to the development of the two-wire system was the demand at that time on the Kellogg Company for certain very large multiple switchboards, involving as many as 18,000 lines in the multiple. Obviously, this necessitated a small jack, and obviously a jack having only two contacts, a tip spring and a sleeve, could be made more easily and with greater durability of this very small size than a jack requiring three or more contacts. Other reasons that were considered were, of course, cheapness in cost of construction and extreme simplicity, which, other things being equal, lends itself to low cost of maintenance. _Line Circuit._ Like the standard Western Electric board for large offices, the Kellogg two-wire board employs two relays for each line, the line relay under the control of the subscriber and in turn controlling the lamp, and a cut-off relay under the control of the operator and in turn controlling the connection of the line relay with the line. The line circuit as originally developed and as widely used by the Kellogg Company is shown in Fig. 350. The extreme simplicity of the jacks is apparent, as is also the fact that but two wires lead through the multiple. Another distinguishing feature is, that all of the multiple and answering jacks are normally cut off from the line at the cut-off relay, but when the cut-off relay operates it serves, in addition to cutting off the line relay, to attach the two limbs of the line to the two wires leading through the multiple and answering jacks. The control of the line relay by the subscriber's switch hook is clear from the figure. The control of the cut-off relay is secured by attaching one terminal of the cut-off relay winding permanently to that wire leading through the multiple which connects with the sleeve contacts of the jack, the other terminal of the cut-off relay being grounded. The way in which this relay is operated will be understood when it is stated that the sleeve contacts of both the answering and calling plugs always carry full battery potential and, therefore, whenever any plug is inserted into any jack, current flows from the sleeve of the jack through the sleeve contact of the jack to ground, through the winding of the cut-off relay, which relay becomes energized and performs the functions just stated. It is seen that the wire running through the multiple to which the sleeve jack contacts are attached, is thus made to serve the double purpose of answering as one side of the talking circuit, and also of performing the functions carried out by the separate or third wire in the three-wire system. It will be shown also that, in addition, this wire is made to lend itself to the purposes of the busy test without any of these functions interfering with each other in any way. [Illustration: Fig. 350. Two-Wire Line Circuit] _Cord Circuit._ The cord circuit in somewhat simplified form is shown in Fig. 351. Here again there are but two conductors to the plugs and two strands to the cords. This greater simplicity is in some measure offset by the fact that four relays are required, two for each plug. This so-called four-relay cord circuit may be most readily understood by considering half of it at a time, since the two relays associated with the answering plug act in exactly the same way as those connected with the calling plug. [Illustration: Fig. 351. Two-Wire Cord Circuit] Associated with each plug of a pair are two relays _1_ and _2_, in the case of the answering cord, and _3_ and _4_ in the case of the calling cord. The coils of the relays _1_ and _2_ are connected in series and bridged across the answering cord, a battery being included between the coils in this circuit. The coils of the relays _3_ and _4_ are similarly connected across the calling cord. A peculiar feature of the Kellogg system is that two batteries are used in connection with the cord circuit, one of them being common to all answering cords and the other to all calling cords. The operation of the system would, however, be exactly the same if a single battery were substituted for the two. _Supervisory Signals._ Considering the relays associated with the answering cord, it is obvious that these two relays _1_ and _2_ together control the circuit of the supervisory lamp _5_, the circuit of this lamp being closed only when the relay _1_ is de-energized and the relay _2_ is energized. We will find in discussing the operation of these that the relay _2_ is wholly under the control of the operator, and that the relay _1_, after its plug has been connected with a line, is wholly under the control of the subscriber on that line. It is through the windings of these two relays that current is fed to the line of the subscriber connected with the corresponding cord. When a plug--the answering plug, for instance--is inserted into a jack, current at once flows from the positive pole of the left-hand battery through the winding of the relay _2_ to the sleeve of the plug, thence to the sleeve of the jack and through the cut-off relay to ground. This at once energizes the supervisory relay _2_ and the cut-off relay associated with the line. The cut-off relay acts, as stated, to continue the tip and sleeve wires associated with the jacks to the line leading to the subscriber, and also to cut off the line relay. The supervisory relay _2_ acts at the same time to attract its armature and thus complete its part in closing the circuit of the supervisory lamp. Whether or not the lamp will be lighted at this time depends on whether the relay _1_ is energized or not, and this, it will be seen, depends on whether the subscriber's receiver is off or on its hook. If off its hook, current will flow through the metallic circuit of the line for energizing the subscriber's transmitter, and as whatever current goes to the subscriber's line must flow through the relay _1_, that relay will be energized and prevent the lighting of the supervisory lamp _5_. If, on the other hand, the subscriber's receiver is on its hook, no current will flow through the line, the supervisory relay will not be energized, and the lamp _5_ will be lighted. In a nutshell, the sleeve supervisory relay normally prevents the lighting of the corresponding supervisory lamp, but as soon as the operator inserts a plug into the jack of the line, the relay _2_ establishes such a condition as to make possible the lighting of the supervisory lamp, and the lighting of this lamp is then controlled entirely by the relay _1_, which is, in turn, controlled by the position of the subscriber's switch hook. _Battery Feed._ A 2-microfarad condenser is included in each strand of the cord, and battery is fed through the relay windings to the calling and called subscribers on opposite sides of these condensers, in accordance with the combined impedance coil and condenser method described in Chapter XIII. Here the relay windings do double duty, serving as magnets for operating the relays and as retardation coils in the system of battery supply. _Complete Cord and Line Circuits._ The complete cord and line circuits of the Kellogg two-wire system are shown in Fig. 352. In the more recent installations of the Kellogg Company the cord and line circuits have been slightly changed from those shown in Figs. 350 and 351, and these changes have been incorporated in Fig. 352. The principles of operation described in connection with the simplified figures remain, however, exactly the same. One of the changes is, that the tip side of the lines is permanently connected to the tips of the jacks instead of being normally cut off by the cut-off relay, as was done in the system as originally developed. Another change is, that the line relay is associated with the tip side of the line, rather than with the sleeve side, as was formerly done. The cord circuit shown in Fig. 352 shows exactly the same arrangement of supervisory relays and exactly the same method of battery feed as in the simplified cord circuit of Fig. 351, but in addition to this the detailed connections of the operator's talking set and of her order-wire keys are indicated, and also the ringing equipment is indicated as being adapted for four-party harmonic work. [Illustration: Fig. 352. Kellogg Two-Wire Board] In connection with this ringing key it may be stated that the springs _7_, _8_, _9_, and _10_ are individually operated by the pressure of one of the ringing key buttons, while the spring _17_, connected with the sleeve side of the calling plug, is always operated simultaneously with the operation of any one of the other springs. As a result the proper ringing circuit is established, it being understood that the upper contacts of the springs _7_, _8_, _9_, and _10_ lead to the terminals of their respective ringing generators, the other terminals of which are grounded. The circuit is, therefore, from the generator, through the ringing key, out through the tip side of the line, back over the sleeve side of the line, and to ground through the spring _17_, resistance _11_, and the battery, which is one of the cord-circuit batteries. The object of this coil _11_ and the battery connection through it to the ringing-key spring is to prevent the falling back of the cut-off relay when the ringing key is operated. This will be clear when it is remembered that the cut-off relay is energized by battery current fed over the sleeve strand of the cord, and obviously, since it is necessary when the ringing key is operated to cut off the supply wire back of the key, this would de-energize the cut-off relay when the ringing key was depressed, and the falling back of the cut-off relay contacts would make it impossible to ring because the sleeve side of the line would be cut off. The battery supply through the resistance _11_ is, therefore, substituted on the sleeve strand of the cord for the battery supply through the normal connection. _Busy Test._ The busy test depends on all of the test rings being at zero potential on an idle line and at a higher potential on a busy line. Obviously, when the line is not switched, the test rings are at zero potential on account of a ground through the cut-off relay. When, however, a plug is inserted in either the answering or multiple jacks, the test rings will all be raised in potential due to being connected with the live side of the battery through the sleeve strand of the cord. Conditions on the line external to the central office cannot make an idle line test busy because, owing to the presence of the cut-off relay, the sleeve contacts of all the jacks are disconnected from the line when it is idle. The test circuit from the tip of the calling plug to ground at the operator's set passes through the tip strand of the cord, thence through a pair of normally closed extra contacts on the supervisory relay _4_, thence in series through all the ringing key springs _10_, _9_, _8_, and _7_, thence through an extra pair of springs _12_ and _13_ on the listening key--closed only when the listening key is operated--and thence to ground through a retardation coil _14_. No battery or other source of potential exists in this circuit between ground and the tip of the calling plug and, therefore, the tip is normally at ground potential. The sleeve ring of the jack being at ground potential if the line is idle, no current will flow and no click will be produced in testing such a line. If, however, the line is busy, the test ring will be at a higher potential and, therefore, current will flow from the tip of the calling plug to ground over the path just traced, and this will cause a rise in potential at the terminal of the condenser _15_ and a momentary flow of current through the tertiary winding _16_ of the operator's induction coil; hence the click. [Illustration: SWITCH ROOM OF CITIZENS' TELEPHONE COMPANY, GRAND RAPIDS, MICH. One of the Earliest Large Automatic Offices.] Obviously the testing circuit from the tip of the calling plug to ground at the operator's set is only useful during the time when the calling plug is not in a jack, and as the tip strand of the calling plug has to do double duty in testing and in serving as a part of the talking circuit, the arrangement is made that the testing circuit will be automatically broken and the talking circuit through the tip strand automatically completed when the plug is inserted into a jack in establishing a connection. This is accomplished by means of the extra contact on the relay _4_, which relay, it will be remembered, is held energized when its corresponding plug is inserted in a jack. During the time when the plug is not inserted, this relay is not energized and the test circuit is completed through the back contact of its right-hand armature. When connection is made at the jack, this relay becomes energized and the tip strand of the cord circuit is made complete by the right-hand lever being pulled against the front contact of this relay. The keys shown to the right of the operator's set are order-wire keys. _Summary of Operation._ We may give a brief summary of the operation of this system as shown in Fig. 352. The left-hand station calls and the line relay pulls up, lighting the lamp. The operator inserts an answering plug in the answering jack, thus energizing the cut-off relay which operates to cut off the line relay and to complete the connection between the jacks and the external line. The act of plugging in by the operator also raises the potential of all the test rings so as to guard the line against intrusion by other callers. The supervisory lamp _5_ remains unlighted because, although the relay _2_ is operated, the relay _1_ is also operated, due to the calling subscriber's receiver being off its hook. The operator throws her listening key, communicates with the subscriber, and, learning that the right-hand station is wanted, proceeds to test that line. If the line is idle, she will get no click, because the tip of her calling plug and the tested ring will be at the same ground potential. She then plugs in and presses the proper ringing-key button to send out the proper frequency to ring the particular subscriber on the line--if there be more than one--the current from the battery through the coil _11_ and spring _17_ serving during this operation to hold up the cut-off relay. As soon as the operator plugs in with the calling plug, the supervisory lamp _6_ lights, assuming that the called subscriber had not already removed his receiver from its hook, due to the fact that the relay _4_ is energized and the relay _3_ is not. As soon as the called subscriber responds, the relay _3_ becomes energized and the supervisory lamp goes out. If the line called for had been busy by virtue of being plugged at another section, the tip of the operator's plug in testing would have found the test ring raised to a potential above the ground, and, as a consequence, current would have flowed from the tip of this plug through the back contact of the right-hand lever of relay _4_, thence through the ringing key springs and the auxiliary listening-key springs to ground through the retardation coil _14_. This would have produced a click by causing a momentary flow of current through the tertiary winding _16_ of the operator's set. _Wiring of Line Circuit._ The more complete wiring diagram of a single subscriber's line, Fig. 353, shows the placing in the circuits of the terminals and jumper wires of the main distributing frame and of the intermediate distributing frame, and also shows how the pilot lamps and night-alarm circuits are associated with a group of lines. The main distributing frame occupies the same relative position in this line circuit as in the Western Electric, being located in the main line circuit outside of all the switchboard apparatus. The intermediate distributing frame occupies a different relative position from that in the Western Electric line. It will be recalled by reference to Fig. 348 that the line lamp and the answering jack were permanently associated with the line and cut-off relays, such mutations of arrangement as were possible at the intermediate distributing frame serving only to vary the connection between the multiple of a line and one of the various groups of apparatus consisting of an answering jack and line lamp and associated relays. In the Kellogg arrangement, Fig. 353, the line and cut-off relays, instead of being permanently associated with the answering jack and line lamp, are permanently associated with the multiple jacks, no changes, of which the intermediate or main frames are capable, being able to alter the relation between a group of multiple jacks and its associated line and cut-off relays. In this Kellogg arrangement the intermediate distributing frame may only alter the connection of an answering jack and line lamp with the multiple and its permanently associated relays. The pilot and night alarm arrangements of Fig. 353 should be obvious from the description already given of other similar systems. [Illustration: Fig. 353. Kellogg Two-Wire Line Circuit] =Dean Multiple Board.= In Fig. 354 are shown the circuits of the multiple switchboard of the Dean Electric Company. The subscriber's station equipment shown at Station _A_ and Station _B_ will be recognized as the Wheatstone-bridge circuit of the Dean Company. _Line Circuit._ The line circuit is easily understood in view of what has been said concerning the Western Electric line circuit, the line relay _1_ being single wound and between the live side of the battery and the ring side of the line. The cut-off relay _2_ is operated whenever a plug is inserted in a jack and serves to sever the connection of the line with the normal line signaling apparatus. _Cord Circuit._ The cord circuit is of the four-relay type, but employs three conductors instead of two, as in the two-wire system. The relay _3_, being in series between the battery and the sleeve contact on the plug, is energized whenever a plug is inserted in the jack, its winding being placed in series with the cut-off relay of the line with which the plug is connected. This completes the circuit through the associated supervisory lamp unless the relay _4_ is energized, the local lamp circuit being controlled by the back contact of relay _4_ and the front contact of relay _3_. It is through the two windings of the relay _4_ that current is fed to the subscriber's station, and, therefore, the armature of this relay is responsive to the movements of the subscriber's hook. As the relay _3_ holds the supervisory lamp circuit closed as long as a plug is inserted in a jack of the line, it follows that during a connection the relay _4_ will have entire control of the supervisory lamp. _Listening Key._ The listening key, as usual, serves to connect the operator's set across the talking strands of the cord circuit, and the action of this in connection with the operator's set needs no further explanation. _Ringing Keys._ The ringing-key arrangement illustrated is adapted for use with harmonic ringing, the single springs _5_, _6_, _7_, and _8_ each being controlled by a separate button and serving to select the particular frequency that is to be sent to line. The two springs _9_ and _10_ always act to open the cord circuit back of the ringing keys, whenever any one of the selective buttons is depressed, in order to prevent interference by ringing current with the other operations of the circuit. Two views of these ringing keys are shown in Figs. 355 and 356. Fig. 356 is an end view of the entire set. In Fig. 355 the listening key is shown at the extreme right and the four selective buttons at the left. When a button is released it rises far enough to cause the disengagement of the contacts, but remains partially depressed to serve as an indication that it was last used. The group of springs at the extreme left of Fig. 355 are the ones represented at _9_ and _10_ in Fig. 354 and by the anvils with which those springs co-operate. [Illustration: Fig. 354. Dean Multiple Board Circuits] _Test._ The test in this Dean system is simple, and, like the Western Electric and Kellogg systems, it depends on the raising of the potential of the test thimbles of all the line jacks of a line when a connection is made with that line by a plug at any position. When an operator makes a test by applying the tip of the calling plug to the test thimble of a busy line, current passes from the test thimble through the tip strand of the cord to ground through the left-hand winding of the calling supervisory relay _4_. The drop of potential through this winding causes the tip strand of the cord to be raised to a higher potential than it was before, and as a result the upper plate of the condenser _11_ is thus altered in potential and this change in potential across the condenser results in a click in the operator's ear. [Illustration: Fig. 355. Dean Party Line Ringing Key] [Illustration: Fig. 356. Dean Party Line Ringing Key] =Stromberg-Carlson Multiple Board.= _Line Circuit._ In Fig. 357 is shown the multiple common-battery switchboard circuits employed by the Stromberg-Carlson Telephone Manufacturing Company. The subscriber's line circuits shown in this drawing are of the three-wire type and, with the exception of the subscriber's station, are the same as already described for the Western Electric Company's system. _Cord Circuit._ The cord circuit employed is of the two-conductor type, the plugs being so constructed as to connect the ring and thimble contacts of the jack when inserted. This cord circuit is somewhat similar to that employed by the Kellogg Switchboard and Supply Company, shown in Fig. 352, except that only one battery is employed, and that certain functions of this circuit are performed mechanically by the inter-action of the armatures of the relays. _Supervisory Signals._ When the answering plug is inserted in a jack, in response to a call, the current passing to the subscriber's station and also through the cut-off relay must flow through the relay _1_, thus energizing it. As the calling subscriber's receiver is at this time removed from the hook switch, the path for current will be completed through the tip of the jack, thence through the tip of the plug, through relay _2_ to ground, causing relay _2_ to be operated and to break the circuit of the answering supervisory lamp. The two relays _1_ and _2_ are so associated mechanically that the armature of _1_ controls the armature of _2_ in such a manner as to normally hold the circuit of the answering supervisory lamp open. But, however, when the plug is inserted in a jack, relay _1_ is operated and allows the operation of relay _2_ to be controlled by the hook switch at the subscriber's station. The supervisory relay _3_ associated with the calling cord is operated when the calling plug is placed in a jack, and this relay normally holds the armature of relay _4_ in an operated position in a similar manner as the armature of relay _1_ controlled that of relay _2_. Supervisory relay _4_ is under the control of the hook switch at the called subscriber's station. _Test._ In this circuit, as in several previously described, when a plug is inserted in a jack of a line, the thimble contacts of the jacks associated with that line are raised to a higher potential than that which they normally have. The operator in testing a busy line, of course having previously moved the listening key to the listening position, closes a path from the test thimble of the jack, through the tip of the calling plug, through the contacts of the relay _4_, the inside springs of the listening key, thence through a winding of the induction coil associated with her set to ground. The circuit thus established allows current to flow from the test thimble of the jack through the winding of her induction coil to ground, causing a click in her telephone receiver. The arrangement of the ringing circuit does not differ materially from that already described for other systems and, therefore, needs no further explanation. [Illustration: Fig. 357. Stromberg-Carlson Multiple Board Circuits] =Multiple Switchboard Apparatus.= Coming now to a discussion of the details of apparatus employed in multiple switchboards, it may be stated that much of the apparatus used in the simpler types is capable of doing duty in multiple switchboards, although, of course, modification in detail is often necessary to make the apparatus fit the particular demands of the system in which it is to be used. _Jacks._ Probably the most important piece of apparatus in the multiple switchboard is the jack, its importance being increased by the fact that such very large numbers of them are sometimes necessary. Switchboards having hundreds of thousands of jacks are not uncommon. The multiple jacks are nearly always mounted in strips of twenty and the answering jacks usually in strips of ten, the length of the jack strip being the same in each case in the same board and, therefore, giving twice as wide a spacing in the answering as in the multiple jacks. The distance between centers in the multiple jacks varies from a quarter of an inch--which is perhaps the extreme minimum--to half an inch, beyond which larger limit there seems to be no need of going in any case. It is customary that the jack strip shall be made of the same total thickness as the distance between the centers of two of its jacks, and from this it follows that the strips when piled one upon the other give the same vertical distance between jack centers as the horizontal distance. In Fig. 358 is shown a strip of multiple and a strip of answering jacks of Western Electric make, this being the type employed in the No. 1 standard switchboards for large exchanges. In Fig. 359 are shown the multiple and answering jacks employed in the No. 10 Western Electric switchboard. The multiple jacks in the No. 1 switchboard are mounted on 3/8-inch centers, the jacks having three branch terminal contacts. The multiple jacks of the No. 10 switchboard indicated in Fig. 359 are mounted on 1/2-inch centers, each jack having five contacts as indicated by the requirement of the circuits in Fig. 349. In Fig. 360 are shown the answering and multiple jacks of the Kellogg Switchboard and Supply Company's two-wire system. The extreme simplicity of these is particularly well shown in the cut of the answering jack, and these figures also show clearly the customary method of numbering jacks. In very large multiple boards it has been the practice of the Kellogg Company to space the multiple jacks on 3/10-inch centers, and in their smaller multiple work, they employ the 1/2-inch spacing. With the 3/10-inch spacing that company has been able to build boards having a capacity of 18,000 lines, that many jacks being placed within the reach of each operator. In all modern multiple switchboards the test thimble or sleeve contacts are drawn up from sheet brass or German silver into tubular form and inserted in properly spaced borings in strips of hard rubber forming the faces of the jacks. These strips sometimes are reinforced by brass strips on their under sides. The springs forming the other terminals of the jack are mounted in milled slots in another strip of hard rubber mounted in the rear of and parallel to the front strip and rigidly attached thereto by a suitable metal framework. In this way desired rigidity and high insulation between the various parts is secured. [Illustration: Fig. 358. Answering and Multiple Jacks for No. 1 Board] _Lamp Jacks._ The lamp jacks employed in multiple work need no further description in view of what has been said in connection with lamp jacks for simple common-battery boards. The lamp jack spacing is always the same as the answering jack spacing, so that the lamps will come in the same vertical alignment as their corresponding answering jacks when the lamp strips and answering jack strips are mounted in alternate layers. [Illustration: Fig. 359. Answering and Multiple Jacks for No. 10 Board] [Illustration: Fig. 360. Answering and Multiple Jacks for Kellogg Two-Wire Board] _Relays._ Next in order of importance in the matter of individual parts for multiple switchboards is the relay. The necessity for reliability of action in these is apparent, and this means that they must not only be well constructed, but that they must be protected from dust and moisture and must have contact points of such a nature as not to corrode even in the presence of considerable sparking and of the most adverse atmospheric conditions. Economy of space is also a factor and has led to the almost universal adoption of the single-magnet type of relay for line and cut-off as well as supervisory purposes. [Illustration: Fig. 361. Type of Line Relay] [Illustration: Fig. 362. Type of Cut-Off Relay] The Western Electric Company employs different types of relays for line, cut-off, and supervisory purposes. This is contrary to the practice of most of the other companies who make the same general type of relay serve for all of these purposes. A good idea of the type of Western Electric line relay, as employed in its No. 1 board, may be had from Fig. 361. As is seen this is of the tilting armature type, the armature rocking back and forth on a knife-edge contact at its base, the part on which it rests being of iron and of such form as to practically complete, with the armature and core, the magnetic circuit. The cut-off relay, Fig. 362, is of an entirely different type. The armature in this is loosely suspended by means of a flexible spring underneath two L-shaped polar extensions, one extending up from the rear end of the core and the other from the front end. When energized this armature is pulled away from the core by these L-shaped pieces and imparts its motion through a hard-rubber pin to the upper pair of springs so as to effect the necessary changes in the circuit. [Illustration: Fig. 363. Western Electric Combined Line and Cut-off Relay] [Illustration: Fig. 364. Western Electric Supervisory Relay] [Illustration: Fig. 365. Line Relay No. 10 Board] Much economy in space and in wiring is secured in the type of switchboards employing cut-off as well as line relays by mounting the two relays together and in making of them, in fact, a unitary piece of apparatus. Since the line relay is always associated with the cut-off relay of the same line and with no other, it is obvious that this unitary arrangement effects a great saving in wiring and also secures a great advantage in the matter of convenience of inspection. Such a combined cut-off and line relay, employed in the Western Electric No. 1 relay board, is shown in Fig. 363. These are mounted in banks of ten pairs, a common dust cap of sheet iron covering the entire group. The Western Electric supervisory relay, Fig. 364, is of the tilting armature type and is copper clad. The dust cap in this case fits on with a bayonet joint as clearly indicated. In Fig. 365 is shown the line relay employed in the Western Electric No. 10 board. [Illustration: Fig. 366. Kellogg Line and Cut-off Relays] [Illustration: Fig. 367. Strip of Kellogg Line and Cut-Off Relays] The Kellogg Company employs the type of relay of which the magnetic circuit was illustrated in Fig. 95. In its multiple boards it commonly mounts the line and cut-off relays together, as shown in Fig. 366. A single, soft iron shell is used to cover both of these, thus serving as a dust shield and also as a magnetic shield to prevent cross-talk between adjacent relays--an important feature, since it will be remembered the cut-off relays are left permanently connected with the talking circuit. Fig. 367, which shows a strip of twenty such pairs of relays, from five of which the covers have been removed, is an excellent detail view of the general practice in this respect; obviously, a very large number of such relays may be mounted in a comparatively small space. The mounting strip shown in this cut is of heavy rolled iron and is provided with openings through which the connection terminals--shown more clearly in Fig. 366--project. On the back of this mounting strip all the wiring is done and much of this wiring--that connecting adjacent terminals on the back of the relay strip--is made by means of thin copper wires without insulation, the wires being so short as to support themselves without danger of crossing with other wires. When these wires are adjacent to ground or battery wires they may be protected by sleeving, so as to prevent crosses. [Illustration: Fig. 368. Monarch Relay] An interesting feature in relay construction is found in the relay of the Monarch Telephone Manufacturing Company shown in Figs. 368 and 369. The assembled relay and its mounting strip and cap are shown in Fig. 368. This relay is so constructed that by the lifting of a single latch not only the armature but the coil may be bodily removed, as shown in Fig. 369, in which the latch is shown in its raised position. As seen, the armature has an L-shaped projection which serves to operate the contact springs lying on the iron plate above the coil. The simplicity of this device is attractive, and it is of convenience not only from the standpoint of easy repairs but also from the standpoint of factory assembly, since by manufacturing standard coils with different characters of windings and standard groups of springs, it is possible to produce without special manufacture almost any combination of relay. [Illustration: Fig. 369. Monarch Relay] =Assembly.= The arrangement of the key and jack equipment in complete multiple switchboard sections is clearly shown in Fig. 370, which shows a single three-position section of one of the small multiple switchboards of the Kellogg Switchboard and Supply Company. The arrangement of keys and plugs on the key shelf is substantially the same as in simple common-battery boards. As in the simple switchboards the supervisory lamps are usually mounted on the hinged key shelf immediately in the rear of the listening and ringing keys and with such spacing as to lie immediately in front of the plugs to which they correspond. The reason for mounting the supervisory lamps on the key shelf is to make them easy of access in case of the necessity of lamp renewals or repairs on the wiring. The space at the bottom of the vertical panels, containing the jacks, is left blank, as this space is obstructed by the standing plugs in front of it. Above the plugs, however, are seen the alternate strips of line lamps and answering jacks, the lamps in each case being directly below the corresponding answering jacks. Above the line lamps and answering jacks in the two positions at the right there are blank strips into which additional line lamps and jacks may be placed in case the future needs of the system demand it. The space above these is the multiple jack space, and it is evident from the small number of multiple jacks in this little switchboard that the present equipment of the board is small. It is also evident from the amount of blank space left for future installations of multiple jacks that a considerable growth is expected. Thus, while there are but four banks of 100 multiple jacks, or 400 in all, there is room in the multiple for 300 banks of 100 multiple jacks, or 3,000 in all. The method of grouping the jacks in banks of 100 and of providing for their future growth is clearly indicated in this figure. The next section at the right of the one shown would contain a duplicate set of multiple jacks and also an additional equipment of answering jacks and lamps. [Illustration: A MULTIPLE MANUAL SWITCHING BOARD FOR TOLL CONNECTIONS IN AN AUTOMATIC SYSTEM Multiple Jacks are Provided for Each Line through Which Toll Connections are Handled Directly.] [Illustration: Fig. 370. Small Multiple Board Section] For ordinary local service no operator would sit at the left-hand position of the section shown, that being the end position, since the operator there would not be able easily to reach the extreme right-hand portion of the third position and would have nothing to reach at her left. This end position in this particular board illustrated is provided with toll-line equipment, a practice not uncommon in small multiple boards. To prevent confusion let us assume that the multiple jack space contains its full equipment of 3,000 jacks on each section. The operator in the center position of the section shown could easily reach any one of the jacks on that section. The operator at the third position could reach any jack on the second and third position of her section, but could not well reach multiple jacks in the first position. She would, however, have a duplicate of the multiple jacks in this first position in the section at her right, _i. e._, in the fourth position, and it makes no difference on what portion of the switchboard she plugs into the multiple so long as she plugs into a jack of the right line. CHAPTER XXVII TRUNKING IN MULTI-OFFICE SYSTEMS It has been stated that a single exchange may involve a number of offices, in which case it is termed a multi-office exchange. In a multi-office exchange, switchboards are necessary at each office in which the subscribers' lines of the corresponding office district terminate. Means for intercommunication between the subscribers in one office and those in any other office are afforded by inter-office trunks extended between each office and each of the other offices. If the character of the community is such that each of the offices has so few lines as to make the simple switchboard suffice for its local connections, then the trunking between the offices may be carried out in exactly the same way as explained between the various simple switchboards in a transfer system, the only difference being that the trunks are long enough to reach from one office to another instead of being short and entirely local to a single office. Such a condition of affairs would only be found in cases where several small communities were grouped closely enough together to make them operate as a single exchange district, and that is rather unusual. The subject of inter-office trunking so far as manual switchboards are concerned is, therefore, confined mainly to trunking between a number of offices each equipped with a manual multiple switchboard. =Necessity for Multi-Office Exchanges.= Before taking up the details of the methods and circuits employed in trunking in multi-office systems, it may be well to discuss briefly why the multi-office exchange is a necessity, and why it would not be just as well to serve all of the subscribers in a large city from a single huge switchboard in which all of the subscribers' lines would terminate. It cannot be denied, when other things are equal, that it is better to have only one operator involved in any connection which means less labor and less liability of error. The reasons, however, why this is not feasible in really large exchanges are several. The main one is that of the larger investment required. Considering the investment first from the standpoint of the subscriber's line, it is quite clear that the average length of subscriber's line will be very much greater in a given community if all of the lines are run to a single office, than will be the case if the exchange district is divided into smaller office districts and the lines run merely from the subscribers to the nearest office. There is a direct and very large gain in this respect, in the multi-office system over the single office system in large cities, but this is not a net gain, since there is an offsetting investment necessary in the trunk lines between the offices, which of course are separate from the subscribers' lines. Approaching the matter from the standpoint of switchboard construction and operation, another strong reason becomes apparent for the employment of more than one office in large exchange districts. Both the difficulties of operation and the expense of construction and maintenance increase very rapidly when switchboards grow beyond a certain rather well-defined limit. Obviously, the limitation of the multiple switchboard as to size involves the number of multiple jacks that it is feasible to place on a section. Multiple switchboards have been constructed in this country in which the sections had a capacity of 18,000 jacks. Schemes have been proposed and put into effect with varying success, for doubling and quadrupling the capacity of multiple switchboards, one of these being the so-called divided multiple board devised by the late Milo G. Kellogg, and once used in Cleveland, Ohio, and St. Louis, Missouri. Each of these boards had an ultimate capacity of 24,000 lines, and each has been replaced by a "straight" multiple board of smaller capacity. In general, the present practice in America does not sanction the building of multiple boards of more than about 10,000 lines capacity, and as an example of this it may be cited that the largest standard section manufactured for the Bell companies has an ultimate capacity of 9,600 lines. European engineers have shown a tendency towards the opposite practice, and an example of the extreme in this case is the multiple switchboard manufactured by the Ericsson Company, and installed in Stockholm, in which the jacks have been reduced to such small dimensions as to permit an ultimate capacity of 60,000 lines. The reasons governing the decision of American engineers in establishing the practice of employing no multiple switchboards of greater capacity than about 10,000 lines, briefly outlined, are as follows: The building of switchboards with larger capacity, while perfectly possible, makes necessary either a very small jack or some added complexity, such as that of the divided multiple switchboard, either of which is considered objectionable. Extremely small jacks and large multiples introduce difficulties as to the durability of the jacks and the plugs, and also they tend to slow down the work of operators and to introduce errors. They also introduce the necessity of a smaller gauge of wire through the multiple than it has been found desirable to employ. Considered from the standpoint of expense, it is evident that as a multiple switchboard increases in number of lines, its size increases in two dimensions, _i. e._, in length of board and height of section, and this element of expense, therefore, is a function of the square of the number of lines. The matter of insurance, both with respect to the risk as to property loss and the risk as to breakdown of the service, also points distinctly in the direction of a plurality of offices rather than one. Both from the standpoint of risk against fire and other hazards, which might damage the physical property, and of risk against interruption to service due to a breakdown of the switchboard itself, or a failure of its sources of current, or an accident to the cable approaches, the single office practice is like putting all one's eggs in one basket. Another factor that has contributed to the adoption of smaller switchboard capacities is the fact that in the very large cities even a 40,000 line multiple switchboard would still not remove the necessity of multi-office exchanges with the consequent certainty that a large proportion of the calls would have to be trunked anyway. Undoubtedly, one of the reasons for the difference between American and European practice is the better results that American operating companies have been able to secure in the handling of calls at the incoming end of trunks. This is due, no doubt, in part to the differences in social and economic conditions under which exchanges are operated in this country and abroad, and also in part to the characteristics of the English tongue when compared to some of the other tongues in the matter of ease with which numbers may be spoken. In America it has been found possible to so perfect the operation of trunking under proper operating conditions and with good equipment as to relieve multi-office practice of many of the disadvantages which have been urged against it. =Classification.= Broadly speaking there are two general methods that may be employed in trunking between exchanges. The first and simplest of these methods is to employ so-called _two-way trunks_. These, as their name indicates, may be used for completing connections between offices in either direction, that is, whether the call originates at one end or the other. The other way is by the use of _one-way trunks_, wherein each trunk carries traffic in one direction only. Where such is the case, one end of the trunk is always used for connecting with the calling subscriber's line and is termed the _outgoing_ end, and the other end is always used in completing the connection with the called subscriber's line, and is referred to as the _incoming_ end. Traffic in the other direction is handled by another set of trunks differing from the first set only in that their outgoing and incoming ends are reversed. As has already been pointed out, a system of trunks employing two-way trunks is called a _single-track system_, and a system involving two sets of one-way trunks is called a _double-track system_. It is to be noted that the terms outgoing and incoming, as applied to the ends of trunks and also as applied to traffic, always refer to the direction in which the trunk handles traffic or the direction in which the traffic is flowing with respect to the particular office under consideration at the time. Thus an _incoming trunk_ at one office is an _outgoing trunk_ at the other. _Two-Way Trunks._ Two-way trunks are nearly always employed where the traffic is very small and they are nearly always operated by having the _A_-operator plug directly into the jack at her end of the trunk and displaying a signal at the other end by ringing over the trunk as she would over an ordinary subscriber's line. The operator at the distant exchange answers as she would on an ordinary line, by plugging into the jack of that trunk, and receives her orders over the trunk either from the originating operator or from the subscriber, and then completes the connection with the called subscriber. Such trunks are often referred to as "ring-down" trunks, and their equipment consists in a drop and jack at each end. In case there is a multiple board at either or both of the offices, then the equipment at each end of the trunk would consist of a drop and answering jack, together with the full quota of multiple jacks. It is readily seen that this mode of operation is slow, as the work that each operator has to do is the same as that in connecting two local subscribers, plus the time that it takes for the operators to communicate with each other over the trunk. _One-Way Trunks._ Where one-way trunks are employed in the double-track system, the trunks, assuming that they connect multiple boards, are provided with multiple jacks only at their outgoing ends, so that any operator may reach them for an outgoing connection, and at their incoming ends they terminate each in a single plug and in suitable signals and ringing keys, the purpose of which will be explained later. Over such trunks there is no verbal communication between the operators, the instructions passing between the operators over separate order-wire circuits. This is done in order that the trunk may be available as much as possible for actual conversation between the subscribers. It may be stated at this point that the duration of the period from the time when a trunk is appropriated by the operators for the making of a certain connection until the time when the trunk is finally released and made available for another connection is called the _holding time_, and this holding time includes not only the period while the subscribers are in actual conversation over it, but also the periods while the operators are making the connection and afterwards while they are taking it down. It may be said, therefore, that the purpose of employing separate order wires for communication between the operators is to make the holding time on the trunks as small as possible and, therefore, for the purpose of enabling a given trunk to take part in as many connections in a given time as possible. In outline the operation of a one-way trunk between common-battery, manual, multiple switchboards is, with modifications that will be pointed out afterwards, as follows: When a subscriber's line signal is displayed at one office, the operator in attendance at that position answers and finding that the call is for a subscriber in another office, she presses an order-wire key and thereby connects her telephone set directly with that of a _B_-operator at the proper other office. Unless she finds that other operators are talking over the order wire, she merely states the number of the called subscriber, and the _B_-operator whose telephone set is permanently connected with that order wire merely repeats the number of the called subscriber and follows this by designating the number of the trunk which the _A_-operator is to employ in making the connection. The _A_-operator, thereupon, immediately and without testing, inserts the calling plug of the pair used in answering the call into the trunk jack designated by the _B_-operator; the _B_-operator simultaneously tests the multiple jack of the called subscriber and, if she finds it not busy, inserts the plug of the designated trunk into the multiple jack of the called subscriber and rings his bell by pressing the ringing key associated with the trunk cord used. The work on the part of the _A_-operator in connecting with the outgoing end of the trunk and on the part of the _B_-operator in connecting the incoming end of the trunk with the line goes on simultaneously, and it makes no difference which of these operators completes the connection first. It is the common practice of the Bell operating companies in this country to employ what is called automatic or machine ringing in connection with the _B_-operator's work. When the _B_-operator presses the ringing key associated with the incoming trunk cord, she pays no further attention to it, and she has no supervisory lamp to inform her as to whether or not the subscriber has answered. The ringing key is held down, after its depression by the operator, either by an electromagnet or by a magnet-controlled latch, and the ringing of the subscriber's bell continues at periodic intervals as controlled by the ringing commutator associated with the ringing machine. When the subscriber answers, however, the closure of his line circuit results in such an operation of the magnet associated with the ringing key as to release the ringing key and thus to automatically discontinue the ringing current. When a connection is established between two subscribers through such a trunk the supervision of the connection falls entirely upon the _A_-operator who established it. This means that the calling supervisory lamp at the _A_-operator's position is controlled over the trunk from the station of the called subscriber, the answering supervisory lamp being, of course, under the control of the calling subscriber as in the case of a local connection. It is, therefore, the _A_-operator who always initiates the taking down of a trunk connection, and when, in response to the lighting of the two lamps, she withdraws her calling plug from the trunk jack, the supervisory lamp associated with the incoming end of the trunk at the other office is lighted, and the _B_-operator obeys it by pulling down the plug. If, upon testing the multiple jack of the called subscriber's line, the _B_-operator finds the line to be busy, she at once inserts the trunk plug into a so-called "busy-back" jack, which is merely a jack whose terminals are permanently connected to a circuit that is intermittently opened and closed, and which also has impressed upon it an alternating current of such a nature as to produce the familiar "buzz-buzz" in a telephone receiver. The opening and closing of this circuit causes the calling supervisory lamp of the _A_-operator to flash at periodic intervals just as if the called subscriber had raised and lowered his receiver, but more regularly. This is the indication to the _A_-operator that the line called for is busy. The buzzing sound is repeated back through the cord circuit of the _A_-operator to the calling subscriber and is a notification to him that the line is busy. Sometimes, as is practiced in New York City, for instance, the buzzing feature is omitted, and the only indication that the calling subscriber receives that the called-for line is busy is being told so by the _A_-operator. This may be considered a special feature and it is employed in New York because there the custom exists of telling a calling subscriber, when the line he has called for has been found busy, that the party will be secured for him and that he, the calling subscriber, will be called, if he desires. A modification of this busy-back feature that has been employed in Boston, and perhaps in other places, is to associate with the busy-back jack at the _B_-operator's position a phonograph which, like a parrot, keeps repeating "Line busy--please call again." Where this is done the calling subscriber, _if he understands what the phonograph says_, is supposed to hang up his receiver, at which time the _A_-operator takes down the connection and the _B_-operator follows in response to the notification of her supervisory lamp. The phonograph busy-back scheme, while ingenious, has not been a success and has generally been abandoned. As a rule the independent operating companies in this country have not employed automatic ringing, and in this case the _B_-operators have been required to operate their ringing keys and to watch for the response of the called subscriber. In order to arrange for this, another supervisory lamp, termed the _ringing lamp_, is associated with each incoming trunk plug, the going out of this lamp being a notification to the _B_-operator to discontinue ringing. =Western Electric Trunk Circuits.= The principles involved in inter-office trunking with automatic ringing, are well illustrated in the trunk circuit employed by the Western Electric Company in connection with its No. 1 relay boards. The dotted dividing line through the center of Fig. 371 represents the separating space between two offices. The calling subscriber's line in the first office is shown at the extreme left and the called subscriber's line in the second office is shown at the extreme right. Both of these lines are standard multiple switchboard lines of the form already discussed. The equipment illustrated in the first office is that of an _A_-board, the cord circuit shown being that of the regular _A_-operator. The outgoing trunk jacks connecting with the trunk leading to the other office are, it will be understood, multipled through the _A_-sections of the board and contain no relay equipment, but the test rings are connected to ground through a resistance coil _1_, which takes the place of the cut-off relay winding of a regular line so far as test conditions and supervisory relay operation are concerned. The equipment illustrated in the second office is that of a _B_-board, it being understood that the called subscriber's line is multipled through both the _A_- and _B_-boards at that office. The part of the equipment that is at this point unfamiliar to the reader is, therefore, the cord circuit at the _B_-operator's board. This includes, broadly speaking, the means: (1) for furnishing battery current to the called subscriber; (2) for accomplishing the ringing of the called subscriber and for automatically stopping the ringing when he shall respond; (3) for performing the ordinary switching functions in connection with the relays of the called subscriber's line in just the same way that an _A_-operator's cord carries out these functions; and (4) for causing the operation of the calling supervisory relay of the _A_-operator's cord circuit in just the same manner, under control of the connected called subscriber, as if that subscriber's line had been connected directly to the _A_-operator's cord circuit. [Illustration: Fig. 371. Inter-Office Connection--Western Electric System] The operation of these devices in the _B_-operator's cord circuit may be best understood by following the establishment of the connection. Assuming that the calling subscriber in the first office desires a connection with the subscriber's line shown in the second office, and that the _A_-operator at the first office has answered the call, she will then communicate by order wire with the _B_-operator at the second office, stating the number of the called subscriber and receiving from that operator in return the number of the trunk to be employed. The two operators will then proceed simultaneously to establish the connection, the _A_-operator inserting the calling plug into the outgoing trunk jack, and the _B_-operator inserting the trunk plug into the multiple jack of the called subscriber's line after testing. We will assume at first that the called subscriber's line is found idle and that both of the operators complete their respective portions of the work at the same time and we will consider first the condition of the calling supervisory relay at the _A_-operator's position. The circuit of the calling supervisory lamp will have been closed through the resistance coil _1_ connected with the outgoing trunk jacks and the lamp will be lighted because, as will be shown, it is not yet shunted out by the operation of its associated supervisory relay. Tracing the circuit of the calling supervisory relay of the _A_-operator's circuit, it will be found to pass from the live side of the battery to the ring side of the trunk circuit through one winding of the repeating coil of the _B_-operator's cord; beyond this the circuit is open, since no path exists through the condenser _2_ bridged across the trunk circuit or through the normally open contacts of the relay _3_ connected in the talking circuit of the trunk. The association of this relay _3_ with the repeating coil and the battery of the trunk is seen to be just the same as that of a supervisory relay in the _A_-operator's cord, and it is clear, therefore, that this relay _3_ will not be energized until the called subscriber has responded. When it is energized it will complete the path to ground through the _A_-operator's calling supervisory relay and operate to shunt out the _A_-operator's calling supervisory lamp in just the same manner as if the _A_-operator's calling plug had been connected directly with the line of the calling subscriber. In other words, the called subscriber in the second office controls the relay _3_, which, in turn, controls the calling supervisory relay of the _A_-operator, which, in turn, shunts out its lamp. The connection being completed between the two subscribers, the _B_-operator depresses one or the other of the ringing keys _5_ or _6_, according to which party on the line is called, assuming that it is a two-party line. It will be noticed that the springs of these ringing keys are not serially arranged in the talking circuit, but the cutting off of the trunk circuit back of the ringing keys is accomplished by the set of springs shown just at the left of the ringing keys, which set of springs _7_ is operated whenever either one of the ringing keys is depressed. An auxiliary pair of contacts, shown just below the group of springs _7_, is also operated mechanically whenever either one of the ringing keys is depressed, and this serves to close one of two normally open points in the circuit of the ringing-key holding magnet _8_. This holding magnet _8_ is so arranged with respect to the contacts of the ringing key that whenever any one of them is depressed by the operator, it will be held depressed as long as the magnet is energized just the same as if the operator kept her finger on the key. The other normally open point in the circuit of the holding magnet _8_ is at the lower pair of contacts of the test and holding relay _9_. This relay is operated whenever the trunk plug is inserted in the jack of a called line, regardless of the position of the subscriber's equipment on that line. The circuit may be traced from the live side of the battery through the trunk disconnect lamp _4_, coil _9_, sleeve strand of cord, and to ground through the cut-off relay of the line. The insertion of the trunk plug into the jack thus leaves the completion of the holding-magnet circuit dependent only upon the auxiliary contact on the ringing key, and, therefore, as soon as the operator presses either one of these keys, the clutch magnet is energized and the key is held down, so that ringing current continues to flow at regular intervals to the called subscriber's station. The ringing current issues from the generator _10_, but the supply circuit from it is periodically interrupted by the commutator _11_ geared to the ringing-machine shaft. This periodically interrupted ringing current passes to the ringing-key contacts through the coil of the ringing cut-off relay _12_, and thence to the subscriber's line. The ringing current is, however, insufficient to cause the operation of this relay _12_ as long as the high resistance and impedance of the subscriber's bell and condenser are in the circuit. It is, however, sufficiently sensitive to be operated by this ringing current when the subscriber responds and thus substitutes the comparatively low resistance and impedance path of his talking apparatus for the previous path through his bell. The pulling up of the ringing cut-off relay _12_ breaks a third normally closed contact in the circuit of the holding coil _8_, de-energizing that coil and releasing the ringing key, thus cutting off ringing current. There is a third brush on the commutator _11_ connected with the live side of the central battery, and this is merely for the purpose of assuring the energizing of the ringing cut-off relay _12_, should the subscriber respond during the interval while the commutator _11_ held the ringing current cut off. The relay _12_ may thus be energized either from the battery, if the subscriber responds during a period of silence of his ringer, or from the generator _10_, if the subscriber responds during a period while his bell is sounding; in either case the ringing current will be promptly cut off by the release of the ringing key. The trunk operator's "disconnect lamp" is shown at _4_, and it is to be remembered that this lamp is lighted only when the _A_-operator takes down the connection at her end, and also that this lamp is entirely out of the control of the subscribers, the conditions which determine its illumination being dependent on the positions of the operators' plugs at the two ends of the trunk. With both plugs up, the lamp _4_ will receive current, but will be shunted to prevent its illumination. The path over which it receives this current may be traced from battery through the lamp _4_, thence through the coil of the relay _9_ and the cut-off relay of the called subscriber's line. This current would be sufficient to illuminate the lamp, but the lamp is shunted by a circuit which may be traced from the live side of battery through the contact of the relay _13_, closed at the time, and through the coil of the trunk cut-off relay coil _14_. The resistance of this coil is so proportioned to the other parts of the circuit as to prevent the illumination of the lamp just exactly as in the case of the shunting resistances of the lamps in the _A_-operator's cord. It will be seen, therefore, that the supply of current to the trunk disconnect lamp is dependent on the trunk plug being inserted into the jack of the subscriber's line and that the shunting out of this lamp is dependent on the energization of the relay _13_. This relay _13_ is energized as long as the _A_-operator's plug is inserted into the outgoing trunk jack, the path of the energizing circuit being traced from the live side of the battery at the second office through the right-hand winding of this relay, thence over the tip side of the trunk to ground at the first office. From this it follows that as long as both plugs are up, the disconnect lamp will receive current but will be shunted out, and as soon as the _A_-operator pulls down the connection, the relay _13_ will be de-energized and will thus remove the shunt from about the lamp, allowing its illumination. The left-hand winding of the relay _13_ performs no operating function, but is merely to maintain the balance of the talking circuit, it being bridged during the connection from the ring side of the trunk to ground in order to balance the bridge connection of the right-hand coil from the live side of battery to the tip side of the trunk circuit. The relay _14_, already referred to as forming a shunt for the trunk disconnect lamp, has for its function the keeping of the talking circuit through the trunk open until such time as the relay _13_ operates, this being purely an insurance against unnecessary ringing of a subscriber in case the _A_-operator should by mistake plug into the wrong trunk. It is not, therefore, until the _A_-operator has plugged into the trunk and the relay _13_ has been operated to cause the energization of the relay _14_ that the ringing of the called subscriber can occur, regardless of what the _B_-operator may have done. The relay _9_ has an additional function to that of helping to control the circuit of the ringing-key holding magnet. This is the holding of the test circuit complete until the operator has tested and made a connection and then automatically opening it. The test circuit of the _B_-operator's trunk may be traced, at the time of testing, from the thimble of the multiple jack under test, through the tip of the cord, thence through the uppermost pair of contacts of the relay _9_ to ground through a winding of the _B_-operator's induction coil. After the test has been made and the plug inserted, the relay _9_, which is operated by the insertion of the plug, acts to open this test circuit and at the same time complete the tip side of the cord circuit. In the upper portion of Fig. 371 the order-wire connections, by which the _A_-operator and the _B_-operator communicate, are indicated. It must be remembered in connection with these that the _A_-operator only has control of this connection, the _B_-operator being compelled necessarily to hear whatever the _A_-operators have to say when the _A_-operators come in on the circuit. [Illustration: Fig. 372. Incoming Trunk Circuit] The incoming trunk circuit employed by the Western Electric Company for four-party line ringing is shown in Fig. 372, it being necessarily somewhat modified from that shown in Fig. 371, which is adapted for two-party line ringing only. In addition to the provision of the four-party line ringing keys, by which positive or negative pulsating current is received over either limb of the line, and to the provision of the regular alternating current ringing key for ringing on single party lines, it is necessary in the ringing cut-off relay to provide for keeping the alternating and the pulsating ringing currents entirely separate. For this reason, the ringing cut-off relay _12_ is provided with two windings, that at the right being in the path of the alternating ringing currents that are supplied to the alternating current key, and that at the left being in the ground return path for all of the pulsating ringing currents supplied to the pulsating keys. With this explanation it is believed that this circuit will be understood from what has been said in connection with Fig. 371. The operation of the holding coil _8_ is the same in each case, the holding magnet in Fig. 372 serving to hold depressed any one of the five ringing keys that may have been used in calling the subscriber. [Illustration: AUTOMATIC EQUIPMENT, MAIN OFFICE, BERKELEY, CALIFORNIA A Feature of Interest Here is That the Cement Floor is Treated with a Filler and Painted, with No Other Covering.] [Illustration: Fig. 373. Western Electric Trunk Ringing Key] The standard four-party line, trunk ringing key of the Western Electric Company is shown in Fig. 373. In this the various keys operate not by pressure but rather by being pulled by the finger of the operator in such a way as to subject the key shaft to a twisting movement. The holding magnet lies on the side opposite to that shown in the figure and extends along the full length of the set of keys, each key shaft being provided with an armature which is held by this magnet until the magnet is de-energized by the action of the ringing cut-off relay. [Illustration: Fig. 374. Trunk Relay] [Illustration: Fig. 375. Trunk Relay] The standard trunk relays employed by the Western Electric Company in connection with the circuits just described are shown in Figs. 374 and 375. In each case the dust-cap or shield is also shown. The relay of Fig. 374 is similar to the regular cut-off relay and is the one used for relays _9_ and _14_ of Figs. 371 and 372. The relay of Fig. 375 is somewhat similar to the subscriber's line relay in that it has a tilting armature, and is the one used at _13_ in Figs. 371 and 372. The trunk relay _3_ in Figs. 371 and 372 is the same as the _A_-operator's supervisory relays already discussed. It has been stated that under certain circumstances _B_-operator's trunk circuits devoid of ringing keys, and consequently of all keys, may be employed. This, so far as the practice of the Bell companies is concerned, is true only in offices where there are no party lines, or where, as in many of the Chicago offices, the party lines are worked on the "jack per station" basis. In "jack per station" working, the selection of the station on a party line is determined by the jack on which the plug is put, rather than by a ringing key, and hence the keyless trunk may be employed. [Illustration: Fig. 376. Keyless Trunk] A keyless trunk as used in New York is shown in Fig. 376. This has no manually operated keys whatever, and the relay _17_, when it is operated, establishes connection between the ringing generator and the conductors of the trunk plug. The relays _3_, _13_, and _12_ operate in a manner identical with those bearing corresponding numbers in Fig. 371. As soon as the trunk operator plugs into the multiple jack of the called subscriber, the relay _16_ will operate for the same reason that the relay _9_ operated in connection with Fig. 371. The trunk disconnect lamp will receive current, but if the operator has already established connection with the other end of the trunk, this lamp will not be lighted because shunted by the relay _17_, due to the pulling up of the armature of the relay _13_. The relay _15_ plays no part in the operation so far described, because of the fact that its winding is short-circuited by its own contacts and those of relay _12_, when the latter is not energized. As a result of the operation of the relay _17_, ringing current is sent to line, the supply circuit including the coil of the relay _12_. As soon as the subscriber responds to this ringing current, the armature of the relay _12_ is pulled up, thus breaking the shunt about the relay _15_, which, therefore, starts to operate in series with the relay _17_, but as its armatures assume their attracted position, the relay _17_ is cut out of the circuit, the coil of the relay _15_ being substituted for that of the relay _17_ in the shunt path around the lamp _4_. The relay _17_ falls back and cuts off the ringing current. The relay _15_ now occupies the place with respect to the shunt around the lamp _4_ that the relay _17_ formerly did, the continuity of this shunt being determined by the energization of the relay _13_. When the _A_-operator at the distant exchange withdraws the calling plug from the trunk jack, this relay _13_ becomes de-energized, breaking the shunt about the lamp _4_ and permitting the display of that lamp as a signal to the operator to take down the connection. It may be asked why the falling back of relay _15_ will not again energize relay _17_ and thus cause a false ring on the called subscriber. This will not occur because both the relays _15_ and _17_ depend for their energization on the closure of the contacts of the relay _13_, and when this falls back the relay _17_ cannot again be energized even though the relay _15_ assumes its normal position. =Kellogg Trunk Circuits.= The provision for proper working of trunk circuits in connection with the two-wire multiple switchboards is not an altogether easy matter, owing particularly to the smaller number of wires available in the plug circuits. It has been worked out in a highly ingenious way, however, by the Kellogg Company, and a diagram of their incoming trunk circuit, together with the associated circuits involved in an inter-office connection, is shown in Fig. 377. [Illustration: Fig. 377. Inter-Office Connection--Kellogg System] This figure illustrates a connection from a regular two-wire multiple subscriber's line in one office, through an _A_-operator's cord circuit there, to the outgoing trunk jacks at that office, thence through the incoming trunk circuit at the other office to the regular two-wire multiple subscriber's line at that second office. The portion of this diagram to be particularly considered is that of the _B_-operator's cord circuit. The trunk circuit terminates in the multipled outgoing trunk jacks at the first office, the trunk extending between offices consisting, of course, of but two wires. We will first consider the control of the calling supervisory lamp in the _A_-operator's cord circuit, it being remembered that this control must be from the called subscriber's station. It will be noticed that the left-hand armature of the relay _1_ serves normally to bridge the winding of relay _2_ across the cord circuit around the condenser _3_. When, however, the relay _1_ pulls up, the coil of relay _4_ is substituted in this bridge connection across the trunk. The relay _2_ has a very high resistance winding--about 15,000 ohms--and this resistance is so great that the tip supervisory relay of the _A_-operator's cord will not pull up through it. As a result, when this relay is bridged across the trunk circuit, the tip relay on the calling side of the _A_-operator's cord circuit is de-energized, just as if the trunk circuit were open, and this results in the lighting of the _A_-operator's calling supervisory lamp. The winding of the relay _4_, however, is of low resistance--about 50 ohms--and when this is substituted for the high-resistance winding of the relay _2_, the tip relay on the calling side of the _A_-operator's cord is energized, resulting in the extinguishing of the calling supervisory lamp. The illumination of the _A_-operator's calling supervisory lamp depends, therefore, on whether the high-resistance relay _2_, or the low-resistance relay _4_, is bridged across the trunk, and this depends on whether the relay _1_ is energized or not. The relay _1_, being bridged from the tip side of the trunk circuit to ground and serving as the means of supply of battery current to the called subscriber, is operated whenever the called subscriber's receiver is removed from its hook. Therefore, the called subscriber's hook controls the operation of this relay _1_, which, in turn, controls the conditions which cause the illumination or darkness of the calling supervisory lamp at the distant office. Assuming that the _A_-operator has received and answered a call, and has communicated with the _B_-operator, telling her the number of the called subscriber, and has received, in turn, the number of the trunk to be used, and that both operators have put up the connection, then it will be clear from what has been said that the calling supervisory lamp of the _A_-operator will be lighted until the called subscriber removes his receiver from its hook, because the tip relay in the _A_-operator's cord circuit will not pull up through the 15,000-ohm resistance winding of the relay _2_. As soon as the subscriber responds, however, the relay _1_ will be operated by the current which supplies his transmitter. This will substitute the low-resistance winding of the relay _4_ for the high-resistance winding of the relay _2_, and this will permit the energizing of the tip supervisory relay of the _A_-operator and put out the calling supervisory lamp at her position. As in the Western Electric circuit, therefore, the control of the _A_-operator's calling supervisory lamp is from the called subscriber's station and is relayed back over the trunk to the originating office. In this circuit, manual instead of automatic ringing is employed, therefore, unlike the Western Electric circuit, means must be provided for notifying the B-operator when the calling subscriber has answered. This is done by placing at the _B_-operator's position a ringing lamp associated with each trunk cord, which is illuminated when the _B_-operator places the plug of the incoming trunk into the multiple jack of the subscriber's line, and remains illuminated until the subscriber has answered. This is accomplished in the following manner: when the operator plugs into the jack of the line called, relay _5_ is energized but is immediately de-energized by the disconnecting of the circuit of this relay from the sleeve conductor of the cord when the ringing key is depressed, the selection of the ringing key being determined by the particular party on the line desired. These ringing keys have associated with them a set of springs _9_, which springs are operated when any one of the ringing keys is depressed. Thus, with a ringing key depressed and the relay _5_ de-energized, the ringing lamp will be illuminated by means of a circuit as follows: from the live side of the battery, through the ringing lamp _12_, through the back contact and armature of the relay _6_, through the armature and contact of relay _4_, then through the armature and front contact of relay _2_--which at this time is the relay bridged across the trunk and, therefore, energized--and thence through the back contact and armature of relay _5_ to ground. When the subscriber removes his receiver from the hook, the relay _1_ will become energized as previously described, and will, therefore, operate relay _6_ to break the circuit of the ringing lamp. The circuit thus established by the operation of relay _1_ is as follows: from the live side of battery, through the winding of relay _6_, through the armature and contact of relay _1_, through the armature and contact of relay _4_, through the armature and front contact of relay _2_, thence through the armature and back contact of relay _5_ to ground. As soon as the _B_-operator notes that the ringing lamp has gone out, she knows that no further ringing is required on that line, thus allowing the operation of relay _5_ and accomplishing the locking out of the ringing lamp during the remainder of that connection. The relay _6_, after having once pulled up, remains locked up through the rear contact of the left-hand armature of relay _5_ and ground, until the plug is removed from the jack. At the end of the conversation, when the _A_-operator has disconnected her cord circuit on the illumination of the supervisory signals, both relays _2_ and _4_ will be in an unoperated condition and will provide a circuit for illuminating the disconnect lamp associated with the _B_-operator's cord. This circuit may be traced as follows: from battery through the disconnect lamp, through the armatures and contacts of relays _2_ and _4_, thence through the front contact and armature of relay _5_ to ground, thus illuminating the disconnect lamp. The ringing lamp will not be re-illuminated at this time, due to the fact that it has been previously locked out by relay _6_. The operator then removes the plug from the jack of the line called, and the apparatus in the trunk circuit is restored to normal condition. In the circuit shown only keys are provided for ringing two parties. This circuit, however, is not confined to the use of two-party lines, but may be extended to four parties by simply duplicating the ringing keys and by connecting them with the proper current for selectively ringing the other stations. The method of determining as to whether the called line is free or busy is similar to that previously described for the _A_-operator's cord circuit when making a local connection, and differs only in the fact that in the case of the trunk cord the test circuit is controlled through the contacts of a relay, whereas in the case of the _A_-operator's cord, the test circuit was controlled through the contacts of the listening key. The function of the resistance _10_ and the battery connected thereto is the same as has been previously described. The general make-up of trunking switchboard sections is not greatly different from that of the ordinary switchboard sections where no trunking is involved. In small exchanges where ring-down trunks are employed, the trunk line equipment is merely added to the regular jack and drop equipment of the switchboard. In common-battery multiple switchboards the _A_-boards differ in no respect from the standard single office multiple boards, except that immediately above the answering jacks and below the multiple there are arranged in suitable numbers the jacks of the outgoing trunks. Where the offices are comparatively small, the incoming trunk portions of the _B_-boards are usually merely a continuance of the _A_-boards, the subscriber's multiple being continuous with and differing in no respect from that on the _A_-sections. Instead of the usual pairs of _A_-operators' plugs, cords, and supervisory equipment, there are on the key and plug shelves of these _B_-sections the incoming trunk plugs and their associated equipment. In large offices it is customary to make the _B_-board entirely separate from the _A_-board, although the general characteristics of construction remain the same. The reason for separate _A_- and _B_-switchboards in large exchanges is to provide for independent growth of each without the growth of either interfering with the other. A portion of an incoming trunk, or _B_-board, is shown in Fig. 378. The multiple is as usual, and, of course, there are no outgoing trunk jacks nor regular cord pairs. Instead the key and plug shelves are provided with the incoming-trunk plug equipments, thirty of these being about the usual quota assigned to each operator's position. In multi-office exchanges, employing many central offices, such, for instance, as those in New York or Chicago, it is frequently found that nearly all of the calls that originate in one office are for subscribers whose lines terminate in some other office. In other words, the number of calls that have to be trunked to other offices is greatly in excess of the number of calls that may be handled through the multiple of the _A_-board in which they originate. It is not infrequent to have the percentage of trunked calls run as high as 75 per cent of the total number of calls originating in any one office, and in some of the offices in the larger cities this percentage runs higher than 90 per cent. [Illustration: Fig. 378. Section of Trunk Switchboard] [Illustration: Fig. 379. Section of Partial Multiple Switchboard] This fact has brought up for consideration the problem as to whether, when the nature of the traffic is such that only a very small portion of the calls can be handled in the office where they originate, it is worth while to employ the multiple terminals for the subscribers' lines on the _A_-boards. In other words, if so great a proportion as 90 per cent of the calls have to be trunked any way, is it worth while to provide the great expense of a full multiple on all the sections of the _A_-board in order to make it possible to handle the remaining 10 per cent of the calls directly by the _A_-operators? As a result of this consideration it has been generally conceded that where such a very great percentage of trunking was necessary, the full multiple of the subscribers' lines on each section was not warranted, and what is known as the partial multiple board has come into existence in large manual exchanges. In these the regular subscribers' multiple is entirely omitted from the _A_-board, all subscribers' calls being handled through outgoing trunk jacks connected by trunks to _B_-boards in the same as well as other offices. In these partial multiple _A_-boards, the answering jacks are multipled a few times, usually twice, so that calls on each line may be answered from more than one position. This multipling of answering jacks does not in any way take the place of the regular multipling in full multiple boards, since in no case are the calls completed through the multiple jacks. It is done merely for the purpose of contributing to team work between the operators. A portion of such a partial multiple _A_-board is shown in Fig. 379. This view shows slightly more than one section, and the regular answering jacks and lamps may be seen at the bottom of the jack space just above the plugs. Above these are placed the outgoing trunk jacks, those that are in use being indicated with white designation strips. Above the outgoing trunk jacks are placed the multiples of the answering jacks, these not being provided with lamps. The partial multiple _A_-section of Fig. 379 is a portion of the switchboard equipment of the same office to which the trunking section shown in Fig. 378 belongs. That this is a large multiple board may be gathered from the number of multiple jacks in the trunking section, 8,400 being installed with room for 10,500. That the board is a portion of an equipment belonging to an exchange of enormous proportions may be gathered from the number of outgoing trunk jacks shown in the _A_-board, and in the great number of order-wire keys shown between each of the sets of regular cord-circuit keys. The switchboards illustrated in these two figures are those of one of the large offices of the New York Telephone Company on Manhattan Island, and the photographs were taken especially for this work by the Western Electric Company. =Cable Color Code.= A great part of the wiring of switchboards requires to be done with insulated wires grouped into cables. In the wiring of manual switchboards as described in the seven preceding chapters, and of automatic and automanual systems and of private branch-exchange and intercommunicating systems described in succeeding chapters, cables formed as follows are widely used: Tinned soft copper wires, usually of No. 22 or No. 24 B. & S. gauge, are insulated, first with two coverings of silk, then with one covering of cotton. The outer (cotton) insulation of each wire is made of white or of dyed threads. If dyed, the color either is solid red, black, blue, orange, green, brown, or slate, or it is striped, by combining one of those colors with white or a remaining color. The object of coloring the wires is to enable them to be identified by sight instead of by electrical testing. Wires so insulated are twisted into pairs, choosing the colors of the "line" and "mate" according to a predetermined plan. An assortment of these pairs then is laid up spirally to form the cable core, over which are placed certain wrappings and an outer braid. A widely used form of switchboard cable has paper and lead foil wrappings over the core, and the outer cotton braid finally is treated with a fire-resisting paint. STANDARD COLOR CODE FOR CABLES +---------------+-------------------------------------------------+ | | MATE | | LINE WIRE +-------+-------+-------+-----------+-------------+ | | White | Red | Black | Red-White | Black-White | +---------------+-------+-------+-------+-----------+-------------+ | Blue | 1 | 21 | 41 | 61 | 81 | | Orange | 2 | 22 | 42 | 62 | 82 | | Green | 3 | 23 | 43 | 63 | 83 | | Brown | 4 | 24 | 44 | 64 | 84 | | Slate | 5 | 25 | 45 | 65 | 85 | | Blue-White | 6 | 26 | 46 | 66 | 86 | | Blue-Orange | 7 | 27 | 47 | 67 | 87 | | Blue-Green | 8 | 28 | 48 | 68 | 88 | | Blue-Brown | 9 | 29 | 49 | 69 | 89 | | Blue-Slate | 10 | 30 | 50 | 70 | 90 | | Orange-White | 11 | 31 | 51 | 71 | 91 | | Orange-Green | 12 | 32 | 52 | 72 | 92 | | Orange-Brown | 13 | 33 | 53 | 73 | 93 | | Orange-Slate | 14 | 34 | 54 | 74 | 94 | | Green-White | 15 | 35 | 55 | 75 | 95 | | Green-Brown | 16 | 36 | 56 | 76 | 96 | | Green-Slate | 17 | 37 | 57 | 77 | 97 | | Brown-White | 18 | 38 | 58 | 78 | 98 | | Brown-Slate | 19 | 39 | 59 | 79 | 99 | | Slate-White | 20 | 40 | 60 | 80 | 100 | +---------------+-------+-------+-------+-----------+-------------+ The numerals represent the pair numbers in the cable. The wires of spare pairs usually are designated by solid red with white mate for first spare pair, and solid black with white mate for second spare pair. Individual spare wires usually are colored red-white for first individual spare, and black-white for second individual spare. CHAPTER XXVIII FUNDAMENTAL CONSIDERATIONS OF AUTOMATIC SYSTEMS =Definition.= The term automatic, as applied to telephone systems, has come to refer to those systems in which machines at the central office, under the guidance of the subscribers, do the work that is done by operators in manual systems. In all automatic telephone systems, the work of connecting and disconnecting the lines, of ringing the called subscriber, even though he must be selected from among those on a party line, of refusing to connect with a line that is already in use, and informing the calling subscriber that such line is busy, of making connections to trunk lines and through them to lines in other offices and doing the same sort of things there, of counting and recording the successful calls made by a subscriber, rejecting the unsuccessful, and nearly all the thousand and one other acts necessary in telephone service, are performed without the presence of any guiding intelligence at the central office. The fundamental object of the automatic system is to do away with the central-office operator. In order that each subscriber may control the making of his own connections there is added to his station equipment a call transmitting device by the manipulation of which he causes the central-office mechanisms to establish the connections he desires. We think that the automatic system is one of the most astonishing developments of human ingenuity. The workers in this development are worthy of particular notice. From occupying a position in popular regard in common with long-haired men and short-haired women they have recently appeared as sane, reasonable men with the courage of their convictions and, better yet, with the ability to make their convictions come true. The scoffers have remained to pray. =Arguments Against Automatic Idea.= Naturally there has been a bitter fight against the automatic. Those who have opposed it have contended: First: that it is too complicated and, therefore, could be neither reliable or economical. Second: that it is too expensive, and that the necessary first cost could not be justified. Third: that it is too inflexible and could not adapt itself to special kinds of service. Fourth: that it is all wrong from the subscribers' point of view as the public will not tolerate "doing its own operating." _Complexity._ This first objection as to complexity, and consequent alleged unreliability and lack of economy should be carefully analyzed. It too often happens that a new invention is cast into outer darkness by those whose opinions carry weight by such words as "it cannot work; it is too complicated." Fortunately for the world, the patience and fortitude which men must possess before they can produce meritorious, though intricate inventions, are usually sufficient to prevent their being crushed by any such offhand condemnation, and the test of time and service is allowed to become the real criterion. It would be difficult to find an art that has gone forward as rapidly as telephony. Within its short life of a little over thirty years it has grown from the phase of trifling with a mere toy to an affair of momentous importance to civilization. There has been a tendency, particularly marked during recent years, toward greater complexity; and probably every complicated new system or piece of apparatus has been roundly condemned, by those versed in the art as it was, as being unable to survive on account of its complication. To illustrate: A prominent telephone man, in arguing against the nickel-in-the-slot method of charging for telephone service once said, partly in jest, "The Lord never intended telephone service to be given in that way." This, while a little off the point, is akin to the sweeping aside of new telephone systems on the sole ground that they are complicated. These are not real reasons, but rather convenient ways of disposing of vexing problems with a minimum amount of labor. Important questions lying at the very root of the development of a great industry may not be put aside permanently in this offhand way. The Lord has never, so far as we know, indicated just what his intentions were in the matter of nickel service; and no one has ever shown yet just what degree of complexity will prevent a telephone system from working. It is safe to say that, if other things are equal, the simpler a machine is, the better; but simplicity, though desirable, is not all-important. Complexity is warranted if it can show enough advantages. If one takes a narrow view of the development of things mechanical and electrical, he will say that the trend is toward simplicity. The mechanic in designing a machine to perform certain functions tries to make it as simple as possible. He designs and re-designs, making one part do the work of two and contriving schemes for reducing the complexity of action and form of each remaining part. His whole trend is away from complication, and this is as it should be. Other things being equal, the simpler the better. A broad view, however, will show that the arts are becoming more and more complicated. Take the implements of the art of writing: The typewriter is vastly more complicated than the pen, whether of steel or quill, yet most of the writing of today is done on the typewriter, and is done better and more economically. The art of printing affords even more striking examples. In telephony, while every effort has been made to simplify the component parts of the system, the system itself has ever developed from the simple toward the complex. The adoption of the multiple switchboard, of automatic ringing, of selective ringing on party lines, of measured-service appliances, and of automatic systems have all constituted steps in this direction. The adoption of more complicated devices and systems in telephony has nearly always followed a demand for the performance by the machinery of the system of additional or different functions. As in animal and plant life, so in mechanics--the higher the organism functionally the more complex it becomes physically. Greater intricacy in apparatus and in methods is warranted when it is found desirable to make the machine perform added functions. Once the functions are determined upon, then the whole trend of the development of the machine for carrying them out should be toward simplicity. When the machine has reached its highest stage of development some one proposes that it be required to do something that has hitherto been done manually, or by a separate machine, or not at all. With this added function a vast added complication may come, after which, if it develops that the new function may with economy be performed by the machine, the process of simplification again begins, the whole design finally taking on an indefinable elegance which appears only when each part is so made as to be best adapted in composition, form, and strength to the work it is to perform. Achievements in the past teach us that a machine may be made to do almost anything automatically if only the time, patience, skill, and money be brought to bear. This is also true of a telephone system. The primal question to decide is, what functions the system is to perform within itself, automatically, and what is to be done manually or with manual aid. Sometimes great complications are brought into the system in an attempt to do something which may very easily and cheaply be done by hand. Cases might be pointed out in which fortunes and life-works have been wasted in perfecting machines for which there was no real economic need. It is needless to cite cases where the reverse is true. The matter of wisely choosing the functions of the system is of fundamental importance. In choosing these the question of complication is only one of many factors to be considered. One of the strongest arguments against intricacy in telephone apparatus is its greater initial cost, its greater cost of maintenance, and its liability to get out of order. Greater complexity of apparatus usually means greater first cost, but it does not necessarily mean greater cost of up-keep or lessened reliability. A dollar watch is more simple than an expensive one. The one, however, does its work passably and is thrown away in a year or so; the other does its work marvelously well and may last generations, being handed down from father to son. Merely reducing the number of parts in a machine does not necessarily mean greater reliability. Frequently the attempt to make one part do several diverse things results in such a sacrifice in the simplicity of action of that part as to cause undue strain, or wear, or unreliable action. Better results may be attained by adding parts, so that each may have a comparatively simple thing to do. [Illustration: WESTERN ELECTRIC COMPANY TYPICAL CHARGING OUTFIT AT DAWSON, GEORGIA] The stage of development of an art is a factor in determining the degree of complexity that may be allowed in the machinery of that art. A linotype machine, if constructed by miracle several hundred years ago, would have been of no value to the printer's art then. The skill was not available to operate and maintain it, nor was the need of the public sufficiently developed to make it of use. Similarly the automatic telephone exchange would have been of little value thirty years ago. The knowledge of telephone men was not sufficiently developed to maintain it, telephone users were not sufficiently numerous to warrant it, and the public was not sufficiently trained to use it. Industries, like human beings, must learn to creep before they can walk. Another factor which must be considered in determining the allowable degree of complexity in a telephone system is the character of the labor available to care for and manage it. Usually the conditions which make for unskilled labor also lend themselves to the use of comparatively simple systems. Thus, in a small village remote from large cities the complexity inherent in a common-battery multiple switchboard would be objectionable. The village would probably not afford a man adequately skilled to care for it, and the size of the exchange would not warrant the expense of keeping such a man. Fortunately no such switchboard is needed. A far simpler device, the plain magneto switchboard--so simple that the girl who manipulates it may also often care for its troubles--is admirably adapted to the purpose. So it is with the automatic telephone system; even its most enthusiastic advocate would be foolish indeed to contend that for all places and purposes it was superior to the manual. These remarks are far from being intended as a plea for complex telephone apparatus and systems; every device, every machine, and every system should be of the simplest possible nature consistent with the functions it has to perform. They are rather a protest against the broadcast condemnation of complex apparatus and systems just because they are complicated, and without regard to other factors. Such condemnation is detrimental to the progress of telephony. Where would the printing art be today if the linotype, the cylinder press, and other modern printing machinery of marvelous intricacy had been put aside on account of the fact that they were more complicated than the printing machinery of our forefathers? That the automatic telephone system is complex, exceedingly complex, cannot be denied, but experience has amply proven that its complexity does not prevent it from giving reliable service, nor from being maintained at a reasonable cost. _Expense._ The second argument against the automatic--that it is too expensive--is one that must be analyzed before it means anything. It is true that for small and medium-sized exchanges the total first cost of the central office and subscribers' station equipment, is greater than that for manual exchanges of corresponding sizes. The prices at which various sizes of automatic exchange equipments may be purchased vary, however, almost in direct proportion to the number of lines, whereas in manual equipment the price per line increases very rapidly as the number of lines increases. From this it follows that for very large exchanges the cost of automatic apparatus becomes as low, and may be even lower than for manual. Roughly speaking the cost of telephones and central-office equipment for small exchanges is about twice as great for automatic as for manual, and for very large exchanges, of about 10,000 lines, the cost of the two for switchboards and telephones is about equal. For all except the largest exchanges, therefore, the greater first cost of automatic apparatus must be put down as one of the factors to be weighed in making the choice between automatic and manual, this factor being less and less objectionable as the size of the equipment increases and finally disappearing altogether for very large equipments. Greater first cost is, of course, warranted if the fixed charges on the greater investment are more than offset by the economy resulting. The automatic screw machine, for instance, costs many times more than the hand screw machine, but it has largely displaced the hand machine nevertheless. _Flexibility._ The third argument against the automatic telephone system--its flexibility--is one that only time and experience has been able to answer. Enough time has elapsed and enough experience has been gained, however, to disprove the validity of this argument. In fact, the great flexibility of the automatic system has been one of its surprising developments. No sooner has the statement been made that the automatic system could not do a certain thing than forthwith it has done it. It was once quite clear that the automatic system was not practicable for party-line selective ringing; yet today many automatic systems are working successfully with this feature; the selection between the parties on a line being accomplished with just as great certainty as in manual systems. Again it has seemed quite obvious that the automatic system could not hope to cope with the reverting call problem, _i. e._, enabling a subscriber on a party line to call back to reach another subscriber on the same line; yet today the automatic system may do this in a way that is perhaps even more satisfactory than the way in which it is done in multiple manual switchboards. It is true that the automatic system has not done away with the toll operator and it probably never will be advantageous to require it to do so for the simple reason that the work of the toll operator in recording the connections and in bringing together the subscribers is a matter that requires not only accuracy but judgment, and the latter, of course, no machine can supply. It is probable also that the private branch-exchange operator will survive in automatic systems. This is not because the automatic system cannot readily perform the switching duties, but the private branch-exchange operator has other duties than the mere building up and taking down of connections. She is, as it were, a door-keeper guarding the telephone door of a business establishment; like the toll operator she must be possessed of judgment and of courtesy in large degree, neither of which can be supplied by machinery. In respect to toll service and private branch-exchange service where, as just stated, operators are required on account of the nature of the service, the automatic system has again shown its adaptability and flexibility. It has shown its capability of working in harmony with manual switchboards, of whatever nature, and there is a growing tendency to apply automatic devices and automatic principles of operation to manual switchboards, whether toll or private branch or other kinds, even though the services of an operator are required, the idea being to do by machinery that portion of the work which a machine is able to do better or more economically than a human being. _Attitude of Public._ The attitude of the public toward the automatic is one that is still open to discussion; at least there is still much discussion on it. A few years ago it did seem reasonable to suppose that the general telephone user would prefer to get his connection by merely asking for it rather than to make it himself by "spelling" it out on the dial of his telephone instrument. We have studied this point carefully in a good many different communities and it is our opinion that the public finds no fault with being required to make its own connections. To our minds it is proven beyond question that either the method employed in the automatic or that in the manual system is satisfactory to the public as long as good service results, and it is beyond question that the public may get this with either. _Subscriber's Station Equipment._ The added complexity of the mechanism at the subscriber's station is in our opinion the most valid objection that can be urged against the automatic system as it exists today. This objection has, however, been much reduced by the greater simplicity and greater excellence of material and workmanship that is employed in the controlling devices in modern automatic systems. However, the automatic system must always suffer in comparison with the manual in respect of simplicity of the subscriber's equipment. The simplest conceivable thing to meet all of the requirements of telephone service at a subscriber's station is the modern common-battery manual telephone. The automatic telephone differs from this only in the addition of the mechanism for enabling the subscriber to control the central-office apparatus in the making of calls. From the standpoint of maintenance, simplicity at the subscriber's station is, of course, to be striven for since the proper care of complex devices scattered all over a community is a much more serious matter than where the devices are centered at one point, as in the central office. Nevertheless, as pointed out, complexity is not fatal, and it is possible, as has been proven, to so design and construct the required apparatus in connection with the subscribers' telephones as to make them subject to an amount of trouble that is not serious. =Comparative Costs.= A comparison of the total costs of owning, operating, and maintaining manual and automatic systems usually results in favor of the automatic, except in small exchanges. This seems to be the consensus of opinion among those who have studied the matter deeply. Although the automatic usually requires a larger investment, and consequently a larger annual charge for interest and depreciation, assuming the same rates for each case, and although the automatic requires a somewhat higher degree of skill to maintain it and to keep it working properly than the manual, the elimination of operators or the reduction in their number and the consequent saving of salaries and contributory expenses together with other items of saving that will be mentioned serves to throw the balance in favor of the automatic. The ease with which the automatic system lends itself to inter-office trunking makes feasible a greater subdivision of exchange districts into office districts and particularly makes it economical, where such would not be warranted in manual working. All this tends toward a reduction in average length of subscribers' lines and it seems probable that this possibility will be worked upon in the future, more than it has been in the past, to effect a considerable saving in the cost of the wire plant, which is the part of a telephone plant that shows least and costs most. =Automatic vs. Manual.= Taking it all in all the question of automatic versus manual may not and can not be disposed of by a consideration of any single one of the alleged features of superiority or inferiority of either. Each must be looked at as a practical way of giving telephone service, and a decision can be reached only by a careful weighing of all the factors which contribute to economy, reliability, and general desirability from the standpoint of the public. Public sentiment must neither be overlooked nor taken lightly, since, in the final analysis, it is the public that must be satisfied. =Methods of Operation.= In all of the automatic telephone systems that have achieved any success whatever, the selection of the desired subscriber's line by the calling subscriber is accomplished by means of step-by-step mechanism at the central office, controlled by impulses sent or caused to be sent by the acts of the subscriber. _Strowger System._ In the so-called Strowger system, manufactured by the Automatic Electric Company of Chicago, the subscriber, in calling, manipulates a dial by which the central-office switching mechanism is made to build up the connection he wants. The dial is moved as many times as there are digits in the called subscriber's number and each movement sends a series of impulses to the central office corresponding in number respectively to the digits in the called subscriber's number. During each pause, except the last one, between these series of impulses, the central-office mechanism operates to shift the control of the calling subscriber's line from one set of switching apparatus at the central office to another. In case a four-digit number is being selected first, the movement of the dial by the calling subscriber will correspond to the thousands digit of the number being called, and the resulting movement of the central-office apparatus will continue the calling subscriber's line through a trunk to a piece of apparatus capable of further extending his line toward the line terminals of the thousand subscribers whose numbers begin with the digit chosen. The next movement of the dial corresponding to the hundreds digit of the called number will operate this piece of apparatus to again extend the calling subscriber's line through another trunk to apparatus representing the particular hundred in which the called subscriber's number is. The third movement of the dial corresponding to the tens digit will pick out the group of ten containing the called subscriber's line, and the fourth movement corresponding to the units digit will pick out and connect with the particular line called. _Lorimer System._ In the Lorimer automatic system invented by the Lorimer Brothers, and now being manufactured by the Canadian Machine Telephone Company of Toronto, Canada, the subscriber sets up the number he desires complete by moving four levers on his telephone so that the desired number appears visibly before him. He then turns a handle and the central-office apparatus, under the control of the electrical conditions thus set up by the subscriber, establishes the connection. In this system, unlike the Strowger system, the controlling impulses are not caused by the movement of the subscriber's apparatus in returning to its normal position after being set by the subscriber. Instead, the conditions established at the subscriber's station by the subscriber in setting up the desired number, merely determine the point in the series of impulses corresponding to each digit at which the stepping impulses local to the central office shall cease, and in this way the proper number of impulses in the series corresponding to each digit is determined. _Magnet- vs. Power-Driven Switches._ These two systems differ radically in another respect. In the Strowger system it is the electrical impulses initiated at the subscriber's apparatus that actually cause the movement of the switching parts at the central office, these impulses energizing electromagnets which move the central-office switching devices a step at a time the desired number of steps. In the Lorimer system the switches are all power-driven and the impulses under the control of the subscriber's instrument merely serve to control the application of this power to the various switching mechanisms. These details will be more fully dealt with in subsequent chapters. _Multiple vs. Trunking._ It has been shown in the preceding portion of this work that the tendency in manual switchboard practice has been away from trunking between the various sections or positions of a board, and toward the multiple idea of operating, wherein each operator is able to complete the connection with any line in the same office without resorting to trunks or to the aid of other operators. Strangely enough the reverse has been true in the development of the automatic system. As long as the inventors tried to follow the most successful practice in manual working, failure resulted. The automatic systems of today are essentially trunking systems and while they all involve multiple connections in greater or less degree, all of them depend fundamentally upon the extending of the calling line by separate lengths until it finally reaches and connects with the called line. _Grouping of Subscribers._ In this connection we wish to point out here two very essential features without which, so far as we are aware, no automatic telephone system has been able to operate successfully. The first of these is the division of the total number of lines in any office of the exchange into comparatively small groups and the employment of correspondingly small switch units for each group. Many of the early automatic systems that were proposed involved the idea of having each switch capable in itself of making connection with any line in the entire office. As long as the number of lines was small--one hundred or thereabouts--this might be all right, but where the lines number in the thousands, it is readily seen that the switches would be of prohibitive size and cost. _Trunking between Groups._ This feature made necessary the employment of trunk connections between groups. By means of these the lines are extended a step at a time, first entering a large group of groups, containing the desired subscriber; then entering the smaller group containing that subscriber; and lastly entering into connection with the line itself. The carrying out of this idea was greatly complicated by the necessity of providing for many simultaneous connections through the switchboard. It was comparatively easy to accomplish the extension of one line through a series of links or trunks to another line, but it was not so easy to do this and still leave it possible for any other line to pick out and connect with any other idle line without interference with the first connection. A number of parallel paths must be provided for each possible connection. Groups of trunks are, therefore, provided instead of single trunks between common points to be connected. The subscriber who operates his instrument in making a call knows nothing of this and it is, of course, impossible for him to give any thought to the matter as to which one of the possible paths he shall choose. It was by a realization of these facts that the failures of the past were turned into the successes of the present. The subscriber by setting his signal transmitter was made to govern the action of the central-office apparatus in the selection of the proper _group_ of trunks. The group being selected, the central-office apparatus was made to act at once _automatically_ to pick out and connect with _the first idle trunk of such group_. Thus, we may say _that the subscriber by the act performed on his signal transmitter, voluntarily chooses the group of trunks, and immediately thereafter the central-office apparatus without the volition of the subscriber picks out the first idle one of this group of trunks so chosen_. This fundamental idea, so far as we are aware, underlies all of the successful automatic telephone-exchange systems. It provides for the possibility of many simultaneous connections through the switchboard, and it provides against the simultaneous appropriation of the same path by two or more calling subscribers and thus assures against interference in the choice of the paths. _Outline of Action._ In order to illustrate this point we may briefly outline the action of the Strowger automatic system in the making of a connection. Assume that the calling subscriber desires a connection with a subscriber whose line bears the number 9,567. The subscriber in making the call will, by the first movement of his dial, transmit nine impulses over his line. This will cause the selective apparatus at the central office, that is at the time associated with the calling subscriber's line, to move its selecting fingers opposite a group of terminals representing the ends of a group of trunk lines leading to apparatus employed in connecting with the ninth thousand of the subscribers' lines. While the calling subscriber is getting ready to transmit the next digit, the automatic apparatus, without his volition, starts to pick out the first idle one of the group of trunks so chosen. Having found this it connects with it and the calling subscriber's line is thus extended to another selective apparatus capable of performing the same sort of function in choosing the proper hundreds group. In the next movement of his dial the calling subscriber will send five impulses. This will cause the last chosen selective switch to move its selective fingers opposite a group of terminals representing the ends of a group of trunks each leading to a switch that is capable of making connection with any one of the lines in the fifth hundred of the ninth thousand. Again during the pause by the subscriber, the switch that chose this group of trunks will start automatically to pick out and connect with the first idle one of them, and will thus extend the line to a selective switch that is capable of reaching the desired line, since it has access to all of the lines in the chosen hundred. The third movement of the dial sends six impulses and this causes this last chosen switch to move opposite the sixth group of ten terminals, so that there has now been chosen the nine hundred and fifty-sixth group of ten lines. The final movement of the dial sends seven impulses and the last mentioned switch connects with the seventh line terminal in the group of ten previously chosen and the connection is complete, assuming that the called line was not already engaged. If it had been found busy, the final switch would have been prevented from connecting with it by the electrical condition of certain of its contacts and the busy signal would have been transmitted back to the calling subscriber. _Fundamental Idea._ This idea of subdividing the subscribers' lines in an automatic exchange, of providing different groups of trunks so arranged as to afford by combination a number of possible parallel paths between any two lines, of having the calling subscriber select, by the manipulation of his instrument, the proper group of trunks any one of which might be used to establish the connection he desires, and of having the central-office apparatus act automatically to choose and connect with an idle one in this chosen group, should be firmly grasped. It appears, as we have said, in every successful automatic system capable of serving more than one small group of lines, and until it was evolved automatic telephony was not a success. _Testing._ As each trunk is chosen and connected with, conditions are established, by means not unlike the busy test in multiple manual switchboards, which will guard that trunk and its associated apparatus against appropriation by any other line or apparatus as long as it is held in use. Likewise, as soon as any subscriber's line is put into use, either by virtue of a call being originated on it, or by virtue of its being connected with as a called line, conditions are automatically established which guard it against being connected with any other line as long as it is busy. These guarding conditions of both trunks and lines, as in the manual board, are established by making certain contacts, associated with the trunks or lines, assume a certain electrical condition when busy that is different from their electrical condition when idle; but unlike the manual switchboard this different electrical condition does not act to cause a click in any one's ear, but rather to energize or de-energize certain electromagnets which will establish or fail to establish the connection according to whether it is proper or improper to do so. _Local and Inter-Office Trunks._ The groups of trunks that are used in building up connections between subscribers' lines may be local to the central office, or they may extend between different offices. The action of the two kinds of trunks, local or inter-office, is broadly the same. CHAPTER XXIX THE AUTOMATIC ELECTRIC COMPANY'S SYSTEM Almost wherever automatic telephony is to be found--and its use is extensive and rapidly growing--the so-called Strowger system is employed. It is so named because it is the outgrowth of the work of Almon B. Strowger, an early inventor in the automatic telephone art. That the system should bear the name of Strowger, however, gives too great prominence to his work and too little to that of the engineers of the Automatic Electric Company under the leadership of Alexander E. Keith. =Principles of Selecting Switch.= The underlying features of this automatic system have already been referred to in the abstract. A better grasp of its principles may, however, be had by considering a concrete example of its most important piece of apparatus--the selecting switch. The bare skeleton of such a switch, sufficient only to illustrate the salient point in its mode of operation, is shown in Fig. 380. The essential elements of this are a vertical shaft capable of both longitudinal and rotary motion; a pawl and ratchet mechanism actuated by a magnet for moving the shaft vertically a step at a time; another pawl and ratchet mechanism actuated by another magnet for rotating the shaft a step at a time; an arm carrying wiper contacts on its outer end, mounted on and moving with the shaft; and a bank of contacts arranged on the inner surface of a section of a cylinder adapted to be engaged by the wiper contacts on this movable arm. These various elements are indicated in the merest outline and with much distortion in Fig. 380, which is intended to illustrate the principles of operation rather than the details as they actually are in the system. In the upper left-hand corner of this figure, the magnet shown will, if energized by impulses of current, attract and release its armature and, in doing so, cause the pawl controlled by this magnet to move the vertical shaft of the switch up a step at a time, as many steps as there are impulses of current. The vertical movement of this shaft will carry the wiper arm, attached to the lower end of the shaft, up the same number of steps and, in doing so, will bring the contacts of this wiper arm opposite, but not engaging, the corresponding row of stationary contacts in the semi-cylindrical bank. Likewise, through the ratchet cylinder on the intermediate portion of the shaft, the magnet shown at the right-hand portion of this figure will, when energized by a succession of electrical impulses, rotate the shaft a step at a time, as many steps as there are impulses. This will thus cause the contacts of the wiper arm to move over the successive contacts in the row opposite to which the wiper had been carried in its vertical movement. [Illustration: Fig. 380. Principles of Automatic Switch] At the lower left-hand corner of this figure, there is shown a pair of keys either one of which, when operated, will complete the circuit of the magnet to which it is connected, this circuit including a common battery. In a certain rough way this pair of key switches in the lower left-hand corner of the drawing may be taken as representing the call-transmitting apparatus at the subscriber's station, and the two wires extending therefrom may be taken as representing the line wires connecting that subscriber's station to the central office; but the student must avoid interpreting them as actual representations of the subscriber's station calling apparatus or the subscriber's line since their counterparts are not to be found in the system as it really exists. Here again accuracy has been sacrificed for ease in setting forth a feature of operation. Still referring to Fig. 380, it will be seen that the bank contacts consist of ten rows, each having ten pairs of contacts. Assume again, for the sake of simplicity, that the exchange under consideration has one hundred subscribers and that each pair of bank contacts represents the terminals of one subscriber's line. Assume further that the key switches in the lower left-hand corner of the figure are being manipulated by a subscriber at that station and that he wishes to obtain a connection with line No. 67. By pressing and releasing the left-hand key six times, he will cause six separate impulses of current to flow through the upper left-hand magnet and this will cause the switch shaft to move up six steps and bring the wiper arm opposite the sixth row of bank contacts. If he now presses and releases his right-hand key seven times, he will, through the action of the right-hand magnet, rotate the shaft seven steps, thus bringing the wipers into contact with the seventh contact of the sixth row and thus into contact with the desired line. As the wiper contacts on the switch arm form the terminals of the calling subscriber's line, it will be apparent that the calling subscriber is now connected through his switch with the line of subscriber No. 67. As stated, each of the pairs of bank contacts are connected with the line of a subscriber; the line, Fig. 380, is shown so connected to the forty-first pair of contacts, that is to the first contact in the fourth row. The selecting switch shown in Fig. 380 would be for the sole use of the subscriber on the line No. 41. Each of the other subscribers would have a similar switch for his own exclusive use. Since any of the switches must be capable of reaching line No. 67, for instance, when moved _up_ six rows and _around_ seven, it follows that the sixty-seventh pair of contacts in each bank of the entire one hundred switches must also be connected together and to line No. 67. The same is, of course, true of all the contacts corresponding to any other number. Multiple connections are thus involved between the corresponding contacts of the banks, in much the same way as in the corresponding jacks in the multiple of a manual switchboard. As a result of this multiple connection of the bank contacts, any subscriber may move the wiper arm of his selecting switch into connection with the line of any other subscriber. _The "Up-and-Around" Movement._ The elemental idea to be grasped by the discussion so far, is the so-called "up-and-around" method of action of the selecting switches employed in this system. This preliminary discussion may be carried a step further by saying that the arrangement is such that when a subscriber presses both his keys and grounds both of the limbs of his line, such a condition is brought about as will cause all holding pawls to be withdrawn from the shaft, and thus allow it to return to its normal position with respect to both its vertical and rotary movements. No attempt has been made in Fig. 380 to show how this is accomplished. =Function of Line Switch.= Such a system as has been briefly outlined in the foregoing would require a separate selecting switch for each subscriber's line and would be limited to use in exchanges having not more than one hundred lines. In the modern system of the Automatic Electric Company, the requirement that each subscriber shall have a selective switch, individual to his own line, has been eliminated by introducing what is called an _individual line switch_ by means of which any one of a group of subscribers' lines, making a call, automatically appropriates one of a smaller group of selecting switches and makes it its own only while the connection exists. =Subdivision of Subscribers' Lines.= The limitation as to the size of the exchange has been overcome, without increasing the number of bank contacts in any selecting switch, by dividing the subscribers' lines into groups of one hundred and causing selecting switches automatically to extend the calling subscriber's line first into a group of groups corresponding, for instance, to the thousand containing the called subscriber's line, and then into the particular group containing the line, and lastly, to connect with the individual line in that group. =Underlying Feature of Trunking System.= It will be remembered that in the chapter on fundamental principles of automatic systems, it was stated that the subscriber, by means of the signal transmitter at his station, was made to govern the action of the central-office apparatus in the selection of a proper group of trunks; and the group being selected, the central-office apparatus was made to act automatically to pick out and connect with the first idle trunk of such group. This selection by the subscriber of a group followed by the automatic selection from among that group forms the basis of the trunking system. It is impossible, by means of any simple diagram, to show a complete scheme of trunking employed, but Fig. 381 will give a fundamental conception of it. This figure shows how a single calling line, indicated at the bottom, may find access into any particular line in an office having a capacity for ten thousand. =Names of Selecting Switches.= Selecting switches of the "up-and-around" type are the means by which the calling line selects and connects with the trunk lines required in building up the connection, and finally selects and connects with the line of the called subscriber. Where such a switch is employed for the purpose of selecting a _trunk_, it is called a selector switch. It is a _first selector_ when it serves to pick out a major group of lines, _i. e._, a group containing a particular thousand lines or, in a multi-office system, a group represented by a complete central office. It is a _second selector_ when it serves to make the next subdivision of groups; a _third selector_ if further subdivision of groups is necessary; and finally it is _a connector_ when it is employed to pick out and connect with the _particular line in the final group of one hundred lines_ to which the connection has been brought by the selectors. In a single office of 10,000-line capacity, therefore, we would have first and second selectors and connectors, the first selectors picking out the thousands, the second selectors the hundreds, and the connectors the individual line. In a multi-office system we may have first, second, and third selectors and connectors, the first selector picking out the office, the second selector the thousands in that office, the third selector the hundreds, and the connector the individual lines. =The Line Switch.= In addition to the selectors and connectors there are line switches, which are comparatively simple, one individual to each line. Each of these has the function, purely automatic, of always connecting a line, as soon as a call is originated on it, to some one of a smaller group of first selectors available to that line. This idea may be better grasped when it is understood that, in the earlier systems of the Automatic Electric Company, there was a first selector permanently associated with each line. By the addition of the comparatively simple line switch, a saving of about ninety per cent of the first selectors was effected, since the number of first selectors was thereby reduced from a number equal to the number of lines in a group to a number equal to the number of simultaneous connections resulting from calls originating in that group. In other words, by the line switch, the number of first selectors is determined by the traffic rather than by the number of lines. =Scheme of Trunking.= With this understanding as to the names and broader functions of the things involved, Fig. 381 may now be understood. The line switch of the single line, as indicated here, has only the power of selection among three trunks, but it is to be understood that in actual practice, it would have access to a greater number, usually ten. So, also, throughout this diagram we have shown the apparatus and trunks arranged in groups of three instead of in groups of ten, only the first three thousands groups being indicated and the first three hundreds groups in each thousand. Again only three levels instead of ten are indicated for each selecting switch, it being understood that in the diagram the various levels are represented by concentric arcs of circles, and the trunk contacts by dots on these arcs. _Line-Switch Action._ When the subscriber, whose line is shown at the bottom of the figure, begins to make a call, the line switch acts to connect his line with one of the first selector trunks available to it. This selection is entirely preliminary and, except to start it, is in no way under the control of the calling subscriber. The calling line now has under its control a first selector which, for the time being, becomes individual to it. Let it be assumed that the line switch found the first of the first selector trunks already appropriated by some other switch, but that the second one of these trunks was found idle. This trunk being appropriated by the line switch places the center one of the first selectors shown under the control of the subscriber's line. This first selector then acts in response to the first set of selective impulses sent out by his signal transmitter. [Illustration: DEAN HARMONIC CONVERTER Dry Cell Type for Magneto Exchange. _The Dean Electric Co._] [Illustration: Fig. 381. Scheme of Trunking] _First Selector Action._ We will assume that the calling subscriber desires to connect with No. 3213. The first movement of the subscriber's signal transmitter will send, therefore, three impulses over the line. These impulses will act on the vertical magnet of the first selector switch to move it up three steps. On this "level" of the contact bank of this switch all of the contacts will represent second selector trunks leading to the _third_ thousand group. The other ends of these trunks will terminate in the wipers and also in the controlling magnets of second selectors serving this thousand. This function on the part of the first selector controlled by the act of the subscriber will have thus selected a _group_ of trunks leading to the _third_ thousand, but the subscriber has nothing to do with which one of the trunks of this group will actually be used. Immediately following the vertical movement of the first selector switch the rotary movement of this switch will start and will continue until the wipers of that switch have found contacts of an idle trunk leading to a second selector. Assuming that the first trunk was the one found idle, the first selector wipers would pause on the first pair of contacts in the third level of its bank, and the trunk chosen may be seen leading from that contact off to the group of second selectors belonging to the third thousand. For clearness, the chosen trunks in this assumed connection are shown heavier than the others. _Second Selector Action._ The next movement of the dial by the subscriber in establishing his desired connection will send two impulses, it being desired to choose the _second_ hundred in the _third_ thousand. The first selector will have become inoperative before this second series of impulses is sent and, therefore, only the second selector will respond. Its vertical magnet acting under the influence of these two impulses will step up its wiper contacts opposite the second row of bank contacts, and the subscriber will thus have chosen the _group_ of trunks leading to the _second_ hundred in the _third_ thousand. Here, again, the automatic operation of picking out the first idle one of this chosen group of trunks will take place without the volition of the subscriber, and it will be assumed that the first two trunks on this level of the second selector were found already engaged and that the third was therefore chosen. The connection continues, as indicated by heavy lines in Fig. 381, to the third one of the connectors in the _second_ hundred of the _third_ thousand. Any one of these connectors would have accomplished the purpose but this is assumed to be the first one found idle by the second selector. _Connector Action._ The third movement of the subscriber's dial will send but one impulse, this corresponding to the _first_ group of ten in the _second_ hundred in the _third_ thousand. This impulse will move the connector shaft up to the first level of bank contacts; and from now on the action of the connector differs radically from that of the selectors. The connector is not searching for an idle trunk in the group but for a particular line and, therefore, having chosen the group of ten lines in the desired hundred, the connector switch waits for further guidance from the subscriber. This comes in the form of the final set of impulses sent by the subscriber's signal transmitter which, in this case, will be three in number, corresponding to the final digit in the number of the called subscriber. This series of impulses will control the rotary movement of the connector wipers which will move along the first level and stop on the third one. The process is seen to be one of successive selection, first of a large group, then of a smaller, again of a smaller, and finally of an individual. If the line is found not busy, the connection between the two subscribers is complete and the called subscriber's bell will be rung. If it is found busy, however, the connector will refuse to connect and will drop back to its normal position, sending a busy signal back to the calling subscriber. The details of ringing and the busy-back operation may only be understood by a discussion of drawings, subsequently to be referred to. =Two-Wire and Three-Wire Systems.= In most of the systems of the Automatic Electric Company in use today the impulses by which the subscriber controls the central-office apparatus flow over one side of the line or the other and return by ground. The metallic circuit is used for talking and for ringing the called subscriber's bell, while ground return circuits, on one side of the line or the other, are used for sending all the switch controlling impulses. Recently this company has perfected a system wherein no ground is required at the subscriber's station and no ground return path is used for any purpose between the subscriber and the central office. This later system is known as the "two-wire" system, and in contra-distinction to it, the earlier and most used system has been referred to as the "three-wire." It is not meant by this that the line circuits actually have three wires but that each line employs three conductors, the two wires of the line and the earth. The three-wire system will be referred to and described in detail, and from it the principles of the two-wire system will be readily understood. [Illustration: Fig. 382. Automatic Wall Set] [Illustration: Fig. 383. Automatic Desk Stand] =Subscriber's Station Apparatus.= The detailed operation of the three-wire system may be best understood by considering the subscriber's station apparatus first. The general appearance of the wall set is shown in Fig. 382, and of the desk set in Fig. 383. These instruments embody the usual talking and call-receiving apparatus of a common-battery telephone and in addition to this, the signal transmitter, which is the thing especially to be considered now. The diagrammatic illustration of the signal transmitter and of the relation that its parts bear to the other elements of the telephone set is shown in Fig. 384. It has already been stated that the subscriber manipulates the signal transmitter by rotating the dial on the face of the instrument. A clearer idea of this dial and of the finger stop for it may be obtained from Figs. 382 and 383. [Illustration: Fig. 384. Circuits of Telephone Set] _Operation._ To make a call for a given number the subscriber removes his receiver from its hook, then places his forefinger in the hole opposite the number corresponding to the first digit of the desired number. By means of the grip thus secured, he rotates the dial until its movement is stopped by the impact of the finger against the stop. The dial is then released and in its return movement it sends the number of impulses corresponding to the first digit in the called number. A similar movement is made for each digit. In Fig. 384 is given a phantom view of the dial, in order to show more clearly the relation of the mechanical parts and contacts controlled by it. For a correct idea of its mechanical action it must be understood that the shaft _1_, the lever _2_, and the interrupter segment _3_ are all rigidly fastened to the dial and move with it. A coiled spring always tends to move the dial and these associated parts back to their normal positions when released by the subscriber, and a centrifugal governor, not shown, limits the speed of the return movement. The subscriber's hook switch is mechanically interlocked with the dial so as to prevent the dial being moved from its normal position until the hook is in its raised position. This interlocking function involves also the pivoted dog _4_. Normally the lower end of this dog lies in the path of the pin _5_ carried on the lever _2_, and thus the shaft, dial, and segment are prevented from any considerable movement when the receiver is on the hook. However, when the receiver is removed from its hook, the upwardly projecting arm from the hook engages a projection on the dog _4_ and moves the dog out of the path of the pin _5_. Thus the dial is free to be rotated by the subscriber. The pin _6_ is mounted in a stationary position and serves to limit the backward movement of the dial by the lever _2_ striking against it. Ground Springs:--Five groups of contact springs must be considered, some of which are controlled wholly by the position of the switch hook, others jointly by the position of the switch hook and the dial, others by the movement of the dial itself, and still others by the pressure of the subscriber's finger on a button. The first of these groups consists of the springs _7_ and _8_, the function of which is to control the continuity of the ground connection at the subscriber's station. The arrangement of these two springs is such that the ground connection will be broken until the subscriber's receiver is removed from its hook. As soon as the receiver is raised, these springs come together in an obvious manner, the dog _4_ being lifted out of the way by the action of the hook. The ledge on the lower portion of the spring _7_ serves as a rest for the insulated arm of the dog _4_ to prevent this dog, which is spring actuated, from returning and locking the dial until after the receiver has been hung up. Bell and Transmitter Springs:--The second group is that embracing the springs _9_, _10_, _11_, and _12_. The springs _10_ and _11_ are controlled by the lower projection from the switch hook, the spring _11_ engaging the spring _12_ only when the hook is down. The spring _10_ engages the spring _9_ only when the hook lever is up and not then unless the dial is in its normal position. While the hook is raised, therefore, the springs _9_ and _10_ break contact whenever the dial is moved and make contact again when it returns to its normal position. The springs _11_ and _12_ control the circuit through the subscriber's bell while the springs _9_ and _10_ control the continuity of the circuit from one side of the line to the other so as to isolate the limbs from each other while the signal transmitter is sending its impulses to the central office. Impulse Springs:--The third group embraces springs _13_, _14_, and _15_ and these are the ones by which the central-office switches are controlled in building up a connection. Something of the prevailing nomenclature which has grown up about the automatic system may be introduced at this point. The movements of the selecting switches at the central office are referred to as _vertical_ and _rotary_ for obvious reasons. On account of this the magnet which causes the vertical movement is referred to as the _vertical magnet_ and that which accomplishes the _rotary_ movement as the _rotary magnet_. It happens that in all cases the selecting impulses sent by the subscriber's station, corresponding respectively to the number of digits in the called subscriber's number, are sent over one side of the line and in nearly all cases these selecting impulses actuate the vertical movements of the selecting switches. For this reason the particular limb of the line over which the selecting impulses are sent is called the _vertical limb_. The other limb of the line is the one over which the single impulse is sent after each group of selecting impulses, and it is this impulse in every case which causes the selector switch to start rotating in its hunt for an idle trunk. This side of the line is, therefore, called _rotary_. For the same reasons the impulses over the vertical side of the line are called _vertical impulses_ and those over the rotary side, _rotary impulses_. The naming of the limbs of the line and of the current impulses _vertical_ and _rotary_ may appear odd but it is, to say the least, convenient and expressive. Coming back to the functions of the third group of springs, _13_, _14_, and _15_, _15_ may be called the _vertical spring_ since it sends vertical impulses; _13_, the _rotary spring_ since it sends rotary impulses; and _14_, the _ground spring_ since, when the hook is up, it is connected with the ground. On the segment _3_ there are ten projections or cams _16_ which, when the dial is moved, engage a projection of the spring _15_. When the dial is being pulled by the subscriber's finger, these cams engage the spring _15_ in such a way as to move it away from the ground spring and no electrical contact is made. On the return of the dial, however, these cams engage the projection on the spring _15_ in the opposite way and the passing of each cam forces this vertical spring into engagement with the ground spring. It will readily be seen, therefore, by a consideration of the spacing of these cams on the segment and the finger holes in the dial that the number of cams which pass the vertical spring _15_ will correspond to the number on the hole used by the subscriber in moving the dial. Near the upper right-hand corner of the segment _3_, as shown in Fig. 384, there is another projection or cam _17_, the function of which is to engage the rotary spring _13_ and press it into contact with the ground spring. Thus, the first thing that happens in the movement of the dial is for the projection _17_ to ride over the hump on the rotary spring and press the contact once into engagement with the ground spring; and likewise, the last thing that happens on the return movement of the dial is for the rotary spring to be connected once to the ground spring after the last vertical impulse has been sent. If both the rotary and vertical sides of the line are connected with the live side of the central-office battery, it follows that every contact between the vertical and the ground spring or between the rotary and the ground spring will allow an impulse of current to flow over the vertical or the rotary side of the line. We may summarize the action of these impulse springs by saying that whenever the dial is moved from its normal position, there is, at the beginning of this movement, a single rotary impulse over the rotary side of the line; and that while the dial returns, there is a series of vertical impulses over the vertical side of the line; and just before the dial reaches its normal position, after the sending of the last vertical impulse, there is another impulse over the rotary side of the line. The mechanical arrangements of the interrupter segment _3_ and its associated parts have been greatly distorted in Fig. 384 in order to make clear their mode of operation. This drawing has been worked out with great care, with this in mind, at a sacrifice of accuracy in regard to the actual structural details. Ringing Springs:--The fourth group of springs in the subscriber's telephone is the ringing group and embraces the springs _18_, _19_, and _20_. The springs _19_ and _20_ are normally closed and maintain the continuity of the talking circuit. When, however, the button attached to the spring _19_--which button may be seen projecting from the instrument shown in Fig. 382, and from the base of the one shown in Fig. 383--is pressed, the continuity of the talking circuit is interrupted and the vertical side of the line is connected with the ground. It is by this operation, after the connection has been made with the desired subscriber's line, that the central-office apparatus acts to send ringing current out on that line. Release Springs:--The fifth set of springs is the one shown at the left-hand side of Fig. 384, embracing springs _21_, _22_, and _23_. The long curved spring _21_ is engaged by the projecting lug on the switch hook when it rises so as to press this spring away from the other two. On the return movement of the hook, however, this spring is pressed to the left so as to bring all three of them into contact, and this, it will be seen, grounds both limbs of the line at the subscriber's station. This combination cannot be effected by any of the other springs at any stage of their operation, and it is the one which results in the energization of such a combination of relays and magnets at the central office as will release all parts involved in the connection and allow them to return to their normal positions ready for another call. _Salient Points._ If the following things are borne in mind about the operation of the subscriber's station apparatus, an understanding of the central-office operations will be facilitated. First, the selective impulses always flow over the vertical side of the line; they are always preceded and always followed by a single impulse over the rotary side of the line. The ringing button grounds the vertical side of the line and the release springs ground both sides of the line simultaneously. =The Line Switch.= The first thing to be considered in connection with the central-office apparatus is the line switch. This, it will be remembered, is the device introduced into each subscriber's line at the central office for the purpose of effecting a reduction of the number of first selectors required at the central office, and also for bringing about certain important functional results in connection with trunking between central and sub-offices. The function of the line switch in connection with the subscriber's line, however, is purely that of reducing the number of first selectors. The line switches of one hundred lines are all associated to form a single unit of apparatus, which, besides the individual line switches, includes certain other apparatus common to those lines. Such a group of one hundred line switches and associated common apparatus is called a _line-switch unit_, or frequently, a _Keith unit_. Confusion is likely to arise in the mind of the reader between the individual line switch and the line-switch unit, and to avoid this we will refer to the piece of apparatus individual to the line as the line switch, and to the complete unit formed of one hundred of these devices as a line-switch unit. _Line and Trunk Contacts._ Each line switch has its own bank of contacts arranged in the arc of a circle, and in this same arc are also placed the contacts of each of the ten individual trunks which it is possible for that line to appropriate. The contacts individual to the subscriber's line in the line switch are all multipled together, the arrangement being such that if a wedge or plunger is inserted at any point, the line contacts will be squeezed out of their normal position so as to engage the contacts of the trunk corresponding to the particular position in the arc at which the wedge or plunger is inserted. A small plunger individual to each line is so arranged that it may be thrust in between the contact springs in the line-switch bank in such manner as to connect any one of the trunks with the line terminals represented in that row, the particular trunk so connected depending on the portion of the arc toward which the plunger is pointed at the time it is thrust in the contacts. These banks of lines and trunk contacts are horizontally arranged, and piled in vertical columns of twenty-five line switches each. The ten trunk contacts are multipled vertically through the line-switch banks, so that the same ten trunks are available to each of the twenty-five lines. We thus have, in effect, an old style, Western Union, cross-bar switchboard, the line contacts being represented in horizontal rows and the trunk contacts in vertical rows, the connection between any line and any trunk being completed by inserting a plunger at the point of intersection of the horizontal and the vertical rows corresponding to that line and trunk. _Trunk Selection._ The plungers by which the lines and trunks are connected are, as has been said, individual to the line, and all of the twenty-five plungers in a vertical row are mounted in such manner as to be normally held in the same vertical plane, and this vertical plane is made to oscillate back and forth by an oscillating shaft so as always _to point the plungers toward a vertical row of trunk contacts that represent a trunk that is not in use at the time_. The to-and-fro movement of this oscillating shaft, called the _master bar_, is controlled by a master switch and the function of this master switch is always to keep the plungers pointed toward the row of contacts of an idle trunk. The thrusting movement of the individual plungers into the contact bank is controlled by magnets individual to the line and under control of the subscriber in initiating a call. As soon as the plunger of a line has been thus thrust into the contact bank so as to connect the terminals of that line with a given trunk, the plunger is no longer controlled by the master bar and remains stationary. The master bar then at once moves all of the other plungers that are not in use so that they will point to the terminals of another trunk that is not in use. The plungers of all the line switches in a group of twenty-five are, therefore, subject to the oscillating movements of the master bar when the line is not connected to a first selector trunk. As soon as a call is originated on a line, the corresponding plunger is forced into the bank and is held stationary in maintaining the connection to a first selector trunk, and all of the other plungers not so engaged, move on so as to be ready to engage another idle trunk. _Trunk Ratio._ The assignment of ten trunks to twenty-five lines would be a greater ratio of trunks than ordinary traffic conditions require. This ratio of trunks to lines is, however, readily varied by multipling the trunk contacts of several twenty-five line groups together. Thus, ten trunks may be made available to one hundred subscribers' lines by multipling the trunks of four twenty-five line switch groups together. In this case the four master bars corresponding to the four groups of twenty-five line switches are all mechanically connected together so as to move in unison under the control of a single master switch. If more than ten and less than twenty-one trunks are assigned to one hundred lines, then each set of ten trunks is multipled to the trunk contacts of fifty line switches, the two master bars of these switches being connected together and controlled by a common master switch. _Structure of Line Switch._ The details of the parts of a line switch that are individual to the line are shown in Fig. 385, the line and trunk contact bank being shown in the lower portion of this figure and also in a separate view in the detached figure at the right. A detailed group of several such line switches with the oscillating master bar is shown in Fig. 386. This figure shows quite clearly the relative arrangement of the line and trunk contact banks, the plungers for each bank, and the master bar. [Illustration: Fig. 385. Line Switch] In practice, four groups of twenty-five line switches each are mounted on a single framework and the group of one hundred line switches, together with certain other portions of the apparatus that will be referred to later, form a line-switch unit. A front view of such a unit is shown in Fig. 387. In order to give access to all portions of the wiring and apparatus, the framework supporting each column of fifty line switches is hinged so as to open up the interior of the device as a whole. A line-switch unit thus opened out is shown in Fig. 388. [Illustration: Fig. 386. Portion of Line-Switch Unit] _Circuit Operation._ The mode of operation of the line switch may be best understood in connection with Fig. 389, which shows in a schematic way the parts of a line switch that are individual to a subscriber's line, and also those that are common to a group of fifty or one hundred lines. Those portions of Fig. 389 which are individual to the line are shown below the dotted line extending across the page. The task of understanding the line switch will be made somewhat easier if Figs. 385 and 389 are considered together. The individual parts of the line switch are shown in the same relation to each other in these two figures with the exception that the bank of line and trunk springs in the lower right-hand corner of Fig. 389 have been turned around edgewise so as to make an understanding of their circuit connections possible. [Illustration: Fig. 387. Line-Switch Unit] [Illustration: Fig. 388. Line-Switch Unit] [Illustration: Fig. 389. Circuits of Line-Switch Unit] The vertical and rotary sides of the subscriber's line are shown entering at the lower left-hand corner of this figure, and they pass to the springs of the contact bank. Immediately adjacent to these springs are the trunk contacts from which the vertical and the rotary limbs of the first selector trunk proceed. The plunger is indicated at _1_, it being in the form of a wheel of insulating material. It is carried on the rod _2_ pivoted on a lever _3_, which, in turn, is pivoted at _4_ in a stationary portion of the framework. A spring _5_, secured to the underside of the lever _3_ and projecting to the left beyond the pivot _4_ of this lever, serves always to press the right-hand portion of the lever _3_ forward in such direction as to tend to thrust it into the contact bank. The plunger is normally held out of the contact bank by means of the latch _6_ carried on the armature _7_ of the trip magnet. When the trip magnet is energized it pulls the armature _7_ to the left and thus releases the plunger and allows it to enter the contact bank. [Illustration: POWER SWITCHBOARD FOR MEDIUM-SIZED OFFICE Mercury Arc Rectifier Panel and Transformer at Right.] The master bar is shown at _8_, and a feather on this bar engages a notch in the segment attached to the rear end of the plunger rod _2_. This master bar is common to all of the plunger rods and by its oscillatory movement, under the influence of the master switch, it always keeps all of the idle plunger bars pointed toward the contacts of an idle trunk. As soon, however, as the trip magnet is operated to cause the insertion of a plunger into the contact bank, the feather on the master bar is disengaged by the notch in the segment of the plunger rod, and the plunger rod is, therefore, no longer subject to the oscillating movement of the master bar. When the release magnet is energized, it attracts its armature _9_ and this lifts the armature _7_ of the trip magnet so that the latch _6_ rides on top of the left-hand end of the lever _3_. Then, when the release magnet is de-energized, the spring _5_, which was put under tension by the latch, moves the entire structure of levers back to its normal position, withdrawing the plunger from the bank of contacts. The notch on the edge of the segment of the plunger rod, when thus released, will probably not strike the feather on the master bar, and the plunger rod will thus not come under the control of the master bar until the master bar has moved, in its oscillation, so that the feather registers with the notch, after which this bar will move with all the others. If, while the plunger is waiting to be picked up by the master bar, the same subscriber should call again, his line will be connected with the same trunk as before. There is no danger in this, however, that the trunk will be found busy, because the master bar will not have occupied a position which would make it possible for any of the lines to appropriate this trunk during the intervening time. _Master Switch._ Associated with each master bar there is a master switch which determines the position in which the master bar shall stop in order that the idle plungers may be pointed always to the contacts of an idle trunk. The arm _10_ of this switch is attached to the master bar and oscillates with it and serves to connect the segment _11_ successively with the contacts _12_, which are connected respectively to the third, or release wire of each first selector trunk. In the figure the arm _10_ is shown resting on the sixth contact of the switch and this sixth contact is connected to a spring _13_ in the line-switch contact bank that has not yet been referred to. As soon as the plunger is inserted into the contact bank, the spring _14_ will be pressed into engagement with the spring _13_, and this spring _14_ is connected with the live side of the battery through the release magnet winding. The contact strip _11_ on the master switch is thus connected through the release magnet to the battery and from this current flows through the left-hand winding of the master-switch relay. This energizes this relay and causes the closure of the circuit of the locking magnet which magnet unlocks the master bar to permit its further rotation. The unlocking of the master bar brings the spring _15_ into engagement with _16_ and thus energizes the master magnet, the armature of which vibrates back and forth after the manner of an electric-bell armature, and steps the wheel _17_ around. The wheel _17_ is mechanically connected to the master bar so that each complete revolution of the wheel will cause one complete oscillation of the master bar. The master bar will thus be moved so as to cause all the idle plungers to sweep through an arc and this movement will stop as soon as the master-switch arm _10_ connects the arc _11_ with one of the contacts _12_ that is not connected to the live side of the battery through the springs _13_ and _14_ of some other line switch. It is by this means that the plungers of the line switches are always kept pointing at the contacts of an idle trunk. The way in which this feature has been worked out must demand admiration and accounts for the marvelous quickness of this line switch. The fact that the plungers are pointed in the right direction before the time comes for their use, leaves only the simple thrusting motion of the plunger to accomplish the desired connection immediately upon the initiation of a call by the subscriber. _Locking Segment._ It will be understood that the locking segment _18_ and the master-switch contact finger _10_ are both rigidly connected with the master bar _8_ and move with it, the locking segment _18_ serving always to determine accurately the angular position at which the master bar and the master-switch arm are brought to rest. _Bridge Cut-Off._ One important feature of automatic switching, particularly as exemplified in the system of the Automatic Electric Company, is the disconnection, after its use, of each operating magnet of each piece of apparatus involved in making a connection. Since these operating magnets are always bridged across the line at the time of their operation and then cut off after they have performed their function, this feature may be referred to as the _bridge cut-off_. _Guarding Functions._ Still another feature of importance is the means for guarding a line or a piece of apparatus that has already been appropriated or made busy, so that it will not be appropriated or connected with for use in some other connection. For this latter purpose contacts and wires are associated with each piece of apparatus, which are multipled to similar contacts on other pieces of apparatus in much the same way and for a similar purpose that the test thimbles in a multiple switchboard are multipled together. Such wires and contacts in the Automatic Electric Company's apparatus are called _private wires_ and _contacts_. The bridge cut-off and guarding functions are provided for in the line switch by a bridge cut-off relay shown in Fig. 389 and also in Fig. 385, it being the upper one of the individual line relays in each of those figures. This bridge cut-off relay is operated as soon as the plunger of the line is thrust into the bank; the contacts _19_ and _20_, closed by the plunger, serving to complete the circuit of this relay. To make clear the bridge cut-off feature it will be noted that the trip magnet of a line switch is connected in a circuit traced from the rotary side of the line through the contacts _21_ and _22_ of the bridge cut-off relay, thence through the coil of the trip magnet to the common wire leading to the spring _23_ of the master-bar locking device and thence to the live side of the battery. Obviously, therefore, as soon as the bridge cut-off relay operates, the trip magnet becomes inoperative and can cause no further action of the line switch because its circuit is broken between the springs _21_ and _22_. The private or guarding feature is taken care of by the action of the plunger in closing contacts _19_ and _20_, since the private wire leading to the bridge cut-off relay is, as has already been stated, connected to ground when these contacts are closed. This private wire leads off and is multipled to the private contacts on all the connectors that have the ability to reach this line, and the fact that this wire is grounded by the line switch as soon as it becomes busy, establishes such conditions at all of the connectors that they will refuse to connect with this line as long as it is busy, in a way that will be pointed out later on. _Relation of Line Switch and Connectors._ The vertical and rotary wires of the subscriber's line are shown leading off to the connector banks at the left-hand side of Fig. 389, and one side of this connection passes through the contacts _24_ and _25_ of the bridge cut-off relay on the line switch. It is through this path that a connection from some other line through a connector to this line is established and it is seen that this path is held open until the bridge cut-off relay of the line switch is operated. For such a connection to this line the bridge cut-off relay of the line switch is operated over the private wire leading from the connector, and the operation of the bridge cut-off relay at this time serves to render inoperative the line switch, so that it will not perform its usual functions should the called subscriber start to make a call after his line had been seized. _Summary of Line-Switch Operation._ To summarize the operation of a line switch when a call is originated on its line, the first movement of the calling subscriber's dial will ground the rotary side of the line and operate the trip magnet. This will cause the plunger to be inserted into the bank, and thus extend the line to the first selector trunk through the closing of the right-hand set of springs shown in the lower right-hand corner of Fig. 389. The insertion of the plunger will also connect the battery through the left-hand winding of the master-switch relay and, by the sequence of operations which follows, cause the master bar to move all of the idle plungers so as to again point them to an idle trunk. The closure of contacts _19_ and _20_ by the plunger causes the operation of the bridge cut-off relay which opens the circuit of the trip magnet, rendering it inoperative; and also establishes ground potential on all the private wire contacts of that line in the banks of the connectors, so as to guard the line and its associated apparatus against intrusion by others. The line is cut through, therefore, to a first selector and all of the line-switch apparatus is completely cut off from the talking circuit. It must be remembered that all of the actions of the line switch, which it has taken so long to describe, occur practically instantaneously and as a result of the first part of the first movement of the subscriber's dial. The line switch has done its work and "gone out of business" before the selective impulses of the first digit begin to take place. =Selecting Switches.= The first selector is now in control of the calling subscriber. The circuits and elements of the first selector switch are shown in Fig. 390. The general mechanical structure of the first selectors, second selectors, and connectors, is the same and may be referred to briefly here. Fig. 391 shows a rear view of a first selector; Fig. 392, a side view of a second selector; and Fig. 393, a front view of a connector. The arrangement of the vertical and rotary magnets, of the selector shafts, and of the contact banks are identical in all three of these pieces of apparatus and all these switches work on the "up-and-around principle" referred to in connection with Fig. 380. It is thought that with the general structure shown in Figs. 391, 392, and 393 in mind, the actual operation may be understood much more readily from Fig. 390. Four magnets--the vertical, the rotary, the private, and the release--produce the switching movements of the machine. These magnets are controlled by various combinations brought upon the circuits by three relays--the vertical, the rotary, and the back release. The fourth relay shown, called the _off-normal_, is purely for signaling purposes, as will be described. _Side Switch._ Another important element of the selecting switches is the so-called side switch which might better be called a pilot switch--but we are not responsible for its name. This side switch has for its function the changing of the control of the subscriber's line to successive portions of the selector mechanism, rendering inoperative those portions that have already performed their functions and that, therefore, are no longer needed. This switch may be seen best in Fig. 392 just above the upper bank of contacts. It is shown in Fig. 390 greatly distorted mechanically so as to better illustrate its electrical functions. [Illustration: Fig. 390. Circuits of First Selector] The contact levers _1_, _2_, _3_, and _4_ of the side switch are carried upon the arm _5_ which is pivoted at _6_. All of these contact levers, therefore, move about _6_ as an axis. The side switch has three positions and it is shown, in Fig. 390, in the first one of these. When the private magnet armature is attracted and released once, the escapement carried by it permits the spring _7_ to move the arm _5_ so as to bring the wipers of the side switch into its second position; the second pulling up and release of the private magnet armature will cause the movement of the side switch wipers into the third position. It is to be noted that the escapement which releases the side switch arm may be moved either by the private or by the rotary magnet, since the armature of the latter has a finger which engages the private magnet armature. [Illustration: Fig. 391. Rear View of First Selector] _Functions of Side Switch._ The functions of the side switch may be briefly outlined in connection with the first selector, as an example. In the first position it extends the control of the subscriber's signal transmitter through the first selector trunk and line relays to the vertical and private magnets so that these magnets will be responsive to the selecting impulses corresponding to the first digit. In its second position it brings about such a condition of affairs that the rotary magnet will be brought into play and automatically move the wipers over the bank contacts in search of an idle trunk. In its third position, both the vertical and rotary relays are cut off and the line is cut straight through to the second selector trunk, and only those parts of the first selector apparatus are left in an operative state which have to do with the private or guarding circuits and with the release. Similar functions are performed by the side switch in connection with the other selecting switches. [Illustration: Fig. 392. Side View of Second Selector] _Release Mechanism._ Another one of the features of the switch that needs to be considered before a detailed understanding of its operation may be had, is the mechanical relation of the holding and the release dog. This dog is shown at _8_ and, in the language of the art, is called the _double dog_. As will be seen, it has two retaining fingers, one adapted to engage the vertical ratchet and the other, the rotary ratchet on the selector shaft. This double dog is pivoted at _9_ and is interlinked in a peculiar way with the armature of the vertical magnet, the armature of the release magnet, and the arm of the side switch. The function of this double dog is to hold the shaft in whatever vertical position it is moved by the vertical magnet and then, when the rotary magnet begins to operate, to hold the shaft in its proper angular position. It will be noted that the fixed dog _10_ is ineffective when the shaft is in its normal angular position. But as soon as the shaft is rotated, this fixed dog _10_ becomes the real holding pawl so far as the vertical movement is concerned. The double dog _8_ is normally held out of engagement with the vertical and the rotary ratchets by virtue of the link connection, shown at _11_, between the release magnet armature and the rear end of the double dog. On the previous release of the switch the attraction of the release magnet armature permitted the link _11_ to hook over the end of the dog _8_ and thus, on its return movement, to pull this dog out of engagement with its ratchets. This movement also resulted in pushing on the link _12_ which is pivoted to the side switch arm _5_, and thus the return movement of the release magnet is made to restore the side switch to its normal position. In order that the double dog may be made effective when it is required, and in order that the side switch may be free to move under the influence of the private magnet, the double dog is released from its connection with the release magnet armature by the first movement of the vertical magnet in a manner which is clear from the drawing. =First Selector Operation.= In discussing the details of operation of the various selectors it will be found convenient to divide the discussion according to the position of the side switch. This will bring about a logical arrangement because it is really the side switch which determines by its position the sequence of operation. [Illustration: Fig. 393. Front View of Connector] _First Position of Side Switch._ This is the position shown in Fig. 390, and is the normal position. The vertical and the rotary lines extending from the calling subscriber are continued by the levers _1_ and _2_ of the side switch through the vertical and the rotary relay coils, respectively, to the live side of battery. The lever _4_ of the side switch in this position connects to ground the circuit leading from the line switch through the release trunk, and the winding of the off-normal relay. This winding is thus put in series with the release magnet of the line switch, but on account of high resistance of the off-normal relay no operation of the release magnet is caused. This will, however, permit such current to flow through the release circuit as will energize the sensitive off-normal relay and cause it to attract its armature and light the off-normal lamp. If this lamp remains lighted more than a brief period of time, it will attract notice and will indicate that the corresponding selector has been appropriated by a line switch and that for some reason the selector has gone no further. This lamp, therefore, is an aid in preventing the continuance of this abnormal condition. The first thing that happens after the line switch has connected the calling subscriber with the first selector is a succession of impulses over the vertical side of the line, this being the set of impulses corresponding in number to the thousands digit or to the office, if there is more than one. It will be understood that here we are considering a single office of ten-thousand-line capacity or thereabouts, and that, therefore, this first set of impulses corresponds to the thousands digit in the called subscriber's line. Each one of these impulses will flow from the battery through the vertical relay and each movement of this relay armature will close the circuit of the vertical magnet and cause the shaft of the selector to be stepped up to the proper level. Immediately following the first series of selecting impulses from the subscriber's station, a single impulse follows over the rotary side of the line. This gives the rotary relay armature one impulse and this in turn closes the circuit of the private magnet once. The single movement of the private magnet armature allows the escapement finger on the arm _5_ to move one step and this brings the side switch contacts into the second position. _Second Position of Side Switch._ In this position lever _4_ of the side switch places a ground on the wire leading through the rotary magnet to a source of interrupted battery current. The impulses which thus flow through the rotary magnet occur at a frequency dependent upon the battery interrupter and this is at a rate of approximately fifteen impulses per second. The rotary magnet will step the selector shaft rapidly around until something occurs to stop these impulses. This something is the finding by the private wiper of an ungrounded private contact in the bank, since all of the contacts corresponding to busy trunks are grounded, as will be explained. The action of the private magnet enters into this operation in the following way: A circuit may be traced from the battery through the private magnet to the third side switch wiper when in its second position, thence through the back release relay to the private wiper. If the wiper is at the time on the private bank contact of a busy trunk, it will find that contact grounded and the private magnet will be energized. The energizing of this magnet will not, however, cause the release of the side switch. It must be energized and de-energized. The private magnet armature will, therefore, be operated by the finger of the rotary magnet armature on the first rotary step. The private magnet will be energized and hold its armature operated if the private wiper finds a ground on the first bank contact and will stay energized as long as the private wiper is passing over private contacts of busy trunks. Its armature will not be allowed to fall back during the passage of the wiper from one trunk to another, because during that interval the finger of the rotary magnet will hold it operated. As soon, however, as the private wiper reaches the private bank contact of an idle trunk, no ground will be found and the circuit of the private magnet will be left open. When the impulse through the rotary magnet ceases, the private magnet armature will fall back and the side switch will be released to its third position. _Third Position of Side Switch._ The first thing to be noted in this position is that the calling line is cut straight through to the second selector trunk, the connection being clean with no magnets bridged across or tapped off. The third wiper of the side switch, when in its third position, is grounded and this connects the release wire of the second selector trunk, on which the switch wipers rest, through the private wiper, the winding of the back release magnet, and the third wiper of the side switch to ground. This establishes a path for the subsequent release current through the back release magnet; and, of equal importance, it places a ground on the private bank contact of that trunk so that the private wiper of any other switch will be prevented from stopping on the contacts of this trunk in the same manner that the wiper of this switch was prevented from stopping on other trunks that were already in use. The fourth lever on the side switch, when in its third position, serves merely to close the circuit of the rotary off-normal lamp. This lamp is for the purpose of calling attention to any first selector switch that has been brought into connection with some second selector trunk and which, for some reason, has failed in its release. These off-normal lamps are so arranged that they may be switched off manually to avoid burning them during the hours of heaviest traffic. At night they afford a ready means of testing for switches that have been left off-normal, since the manual switches controlling these lamps may then be closed, and any lamps which burn will show that the switches corresponding to them are off-normal. Simple tests then suffice to show whether they are properly or improperly in their off-normal position. _Release of the First Selector._ As will be shown later, the normal way of releasing the switches is from the connector back over the release wire. It is sufficient to say at this point that when the proper time for release comes, an impulse of current will come back over the second selector trunk release wire through the private wiper, to the back release relay magnet, and thence to ground through the third wiper of the side switch which is in its third position. It may be asked why the back release magnet was not energized during the previous operations described, when current passed through it. The reason for this is that in those previous operations the private magnet was always included in series in the circuit and on account of the high resistance of the private magnet, sufficient current did not pass through the back release magnet to energize it. When the back release relay is energized, it closes the circuit of the release magnet and thus, through the link _11_, draws the double dog away from its engagement with the shaft ratchets and at the same time, through the link _12_, restores the side switch to its normal position. Whenever the release magnet is operated it acts as a relay to close a pair of contacts associated with it and thus to momentarily ground the release wire of the first selector trunk extending back to the line switch. Referring to Fig. 389, it will be seen that this path leads through the contacts _13_ and _14_ and the release magnet to the battery. It is by this means that the line switch is released, the release impulse being relayed back from the first selector. =Second Selector Operation.= For the purpose of considering the action of the second selector, we will go back to the point where the first selector had connected with a second selector trunk and where its side switch had moved into its third position. In this condition, it will be remembered, the trunk line was cut through to a second selector trunk and all first selector apparatus cleared from the talking circuit. The second selector chosen is one corresponding to the thousands group as determined by the first digit of the called subscriber's number. The circuits of a second selector are shown in Fig. 394 and it must be borne in mind that the mechanical arrangements for producing the vertical and the rotary movement of the shaft and for operating the side switch are practically the same as those of the first selector. As in the first selector, the sequence of operation is controlled by the successive positions of the side switch, the first position permitting the selection of the hundreds corresponding to the vertical impulses, the second position allowing the selector to search for an idle trunk in that hundred, and the third position cutting the trunk through and clearing the circuit of obstructing apparatus. _First Position of Side Switch._ The first thing that happens when the subscriber begins to move his dial in the transmission of the second series of selecting impulses is the sending of a preliminary impulse over the rotary side of the line. This, in the case of the second selector, energizes the rotary relay which, in turn, energizes the private magnet; but the private magnet in the case of the second selector can do nothing toward the release of the side switch because the projection _5'_, on the side switch arm _5_, meets a projection on the rear of the selector shaft which thus prevents the movement of the side switch arm _5_ until the selector shaft has been moved out of its normal position. Immediately after the establishment of the connection to the selector, the second set of selecting impulses comes in over the vertical wire from the subscriber's station. These impulses, corresponding in number to the hundreds digit, will energize the vertical relay and cause it, in turn, to energize the vertical magnet, stepping up the selector shaft to the level corresponding to the hundred sought. The single rotary impulse, which follows just before the subscriber's dial reaches its normal position, will energize the rotary relay of the second selector. This, in turn, energizes the private magnet which makes a single movement of its armature and allows the escapement finger on the side switch arm to move one step and bring the side switch contacts into the second position. [Illustration: Fig. 394. Circuits of Second Selector] _Second Position of Side Switch._ No detailed discussion of this is necessary, since, with the side switch in its second position, the actions which occur in causing the wipers of the second selector to seek and connect with an idle trunk line, are exactly the same as in the case of the first selector. When the second selector wipers finally reach a resting place on the bank contacts, the private magnet armature, operated during the hunting process, is released and the side switch is thus shifted into the third position. _Third Position of Side Switch._ The moving of the side switch into its final position brings about the same state of affairs with respect to the second selector that already exists with respect to the first selector. The trunk line is cut straight through and all bridge circuits or by-paths from it are cut off. The same guarding conditions are established to prevent other lines or other pieces of apparatus from making connections that will interfere with the one being established, and the same provisions are made for working the back release when the proper impulse comes from the connector, and for passing this back release impulse on to the first selector in the same way that the first selector passes it on to the line switch. The line of the calling subscriber has now been extended to a connector, and that connector is one of a group--usually ten--which alone has the ability to reach the particular hundred lines containing the line of the desired subscriber. The selection has, therefore, been narrowed down from one in ten thousand to one in one hundred. =The Connector=--_Its Functions._ It has already been stated that the connector is of the same general type of apparatus as the first and the second selectors. Unlike the first and the second selectors, however, the connector is required to make a double selection under the guidance of the subscriber. The first selector makes a single selection of a group under the guidance of the subscriber and then an automatic selection in that group not controlled by the subscriber. So it is with the second selector. The connector, however, makes a selection of a group of ten under the guidance of the subscriber and then, again under the guidance of the subscriber, it picks out a particular one of that group. The connector also has other functions in relation to the ringing of the called subscriber and the giving of a busy signal to the calling subscriber in case the line wanted is found busy. It has still other functions in that the talking current, which is finally supplied to connected subscribers, is supplied through paths furnished by it. _Location of the Connectors._ Connectors are the only ones of the selecting switches that are in any sense individual to the subscribers' lines. None of them is individual to a subscriber's line, but it may be said that a group of ten connectors is individual to a group of one hundred subscribers' lines. Since each group of one hundred lines has a group of connectors of its own and since each one hundred lines also has a line-switch unit of its own, and since the lines of this group must be multipled through the bank contacts of the connectors of this individual group and through the bank contacts of the line switches of this particular unit, it follows that on account of the wiring problems involved there is good reason for mounting the connectors in close proximity to the line switches representing the same group of lines. Some help in the grasping of this thought may result if it be remembered that the line switch is, so to speak, the point of entry of a call and that the connector is the point of exit, and, in order to reduce the amount of wiring and to economize space, the point of exit and the point of entry are made as close together as possible. The relative locations and grouping of the line switches and connectors are clearly shown in Fig. 395, which is a rear view of the same line-switch unit that was illustrated in Figs. 387 and 388. [Illustration: GAS ENGINE AND POWER BOARD Citizens' Telephone Co., Racine, Wis. _The Dean Electric Co._] =Operation of the Connector.= The circuits of the connector are shown in Fig. 396. In addition to the features that have been pointed out in the first and the second selectors, all of which are to be found, with some modifications, perhaps, in the connector, there must be considered the features in the connector of busy-signal operation, of ringing the called subscriber, of battery supply to both subscribers, and of the trunk release operation. These may be best understood by tracing through the operations of the connector from the time it is picked up by a second selector until the connection is finally completed, or until the busy signal has been given in case completion was found impossible. As in the first and the second selectors, the sequence of operations is determined by the position of the side switch. [Illustration: Fig. 395. Connector Side of Line-Switch Unit] [Illustration: Fig. 396. Circuits of Connector] _First Position of Side Switch._ The connector in a ten-thousand-line system is the recipient of the impulses resulting from the third and fourth movements of the subscriber's dial. Considering the third movement of the subscriber's dial, the first impulse resulting from it comes over the rotary side of the line and results in the rotary relay attracting its armature once. This results in a single impulse through the private magnet which, however, does nothing because the projection _5'_ strikes against a projection on the selector shaft. These two projections interfere only when the selector shaft is in its normal position. Then follows the series of impulses from the subscriber's station corresponding to the tens digit in the called subscriber's number. These pass over the vertical side of the line and through the vertical relay, energizing that relay a corresponding number of times. The vertical magnet, as in the case of the first and the second selectors, is included in the circuit controlled by the vertical relay and this results in the connector shaft being stepped up to the level corresponding to the particular tens group containing the called subscriber's number. It will be noted that the impulses from the vertical side of the line, which cause this selection, pass through one winding _13_ of the calling battery supply relay. This relay is operated by these vertical selecting impulses, but in this position of the side switch the closure of its local circuits accomplishes nothing. Immediately after the tens group of selecting impulses over the vertical side of the line, there follows a single rotary impulse from the subscriber's station which, as in the case of the first and the second selectors, energizes the rotary relay and causes it to give one impulse to the private magnet. This impulse is now able, since the shaft has moved from its normal position, to release the side switch arm one notch, and the side switch, therefore, moves into its second position. _Second Position of Side Switch._ It is principally in this second position of the side switch that the connector selecting function differs from that of the first and the second selector. There is no trunk to be hunted, but rather the rotary movement of the connector wipers must be made in response to the impulses, from the subscriber's station, which correspond to the units digit in the selected number. The first impulse corresponding to the fourth movement of the subscriber's dial is a rotary one, and, as usual, it passes through the rotary relay winding and this, in turn, gives an impulse to the private magnet. The private magnet at this time has already released the side switch arm to its second position, but it is unable to release it further because of a feather on the wiper shaft--which projects just far enough to engage the lug _5'_, when the shaft is in its normal angular position--thus preventing the side switch arm from moving farther than its second position. Then follows over the vertical side of the line the last set of selecting impulses corresponding to the units digit. This, as before, energizes the vertical relay, but in the second position of the side switch, it is to be noted, that the vertical relay no longer controls the vertical magnet; the side switch has shifted the control of the vertical relay to the rotary magnet. The rotary magnet is, therefore, energized a number of times corresponding to the last digit in the called number and the wipers of the connectors are thus brought to the contacts of the line sought--their final goal. At this point many things may happen, and the things that do happen depend on whether the called subscriber's line is idle or busy. Called-Line Busy:--It will first be assumed that the called line is busy. The testing operation at the connectors occurs in the second position of the side switch. If the called line is busy, it will be either because it is connected to by some other connector or because it has itself made a call. In the former case the private contacts of that line in the banks of all the connectors serving that hundreds group of lines will be grounded through the private wiper of some other connector. That this is so, may be seen by tracing the circuit from the private wiper on the shaft to the third side switch wiper which is grounded in the third position; the other connector that has already engaged the line will, of course, have its side switch in its final, or third position. Again, if the line called is busy, because a call has already been made from this line to some other line, the private contacts on the connectors corresponding to the line will be grounded, as will be seen by tracing from the private bank contacts, which are shown in Fig. 396, through the private wire to the line switch, which is shown in Fig. 389, and from thence to ground through the springs _19_ and _20_, which are brought together when the line switch is operated. In any event, therefore, the determining condition of a busy line is that its private bank contacts on all connectors of its group shall be grounded. Under the present assumed condition, therefore, the connector wipers, which have been brought to the bank contacts of the desired line, will find a ground at the private bank contact. The connector shaft stops for an instant on the contacts of this busy line and immediately there follows over the rotary side of the line the inevitable single rotary impulse. This energizes the rotary relay and this, as usual, energizes the private magnet. Remembering now that the connector side switch is in its second position and that the private wiper of the connector has found a ground, we may trace back from the private wiper through the third side switch wiper to its second contact; thence through the contact springs _14_ and _15_, closed by the private magnet; thence through the release magnet; thence through the contact springs _16_ and _17_ of the calling battery supply relay to the live side of the battery. This calling battery supply relay will, at this time, have its core energized because the coil _18_ is in series with the rotary relay coil which, as just stated, was energized by the last rotary impulse. This series of operations has led to the energizing of the release magnet, and, as a result, the double dog of the connector is pulled out of the connector shaft ratchets and the shaft and the side switch are restored to their normal position. Busy-Back Signal:--The connector has dropped back to normal in all respects. The calling subscriber, not knowing this, presses his ringing button. This grounds the vertical side of the line at his station and operates the vertical relay at the connector. This steps the shaft of the connector up one step and causes the closure of the contacts _19_ and _20_ at the top of the connector shaft. This establishes a connection to a circuit carrying periodically interrupted battery current on which an inductive hum is placed. This circuit may be traced from this source through the springs _20_ and _19_ to the first wiper of the side switch, thence through the normally closed contacts of the ringing relay to the rotary side of the line, and the varying potential to which this path is subjected produces an inductive flow back to the calling subscriber's telephone, and gives him the necessary signal which consists of a hum or buzzing noise with which all users of automatic systems soon become familiar. Release on Busy Connection:--The connector, since its last release, has been stepped up one notch and must again be released. When the subscriber hangs up his receiver after receiving the busy signal, he grounds both sides of his line momentarily by the action of the springs _21_, _22_, and _23_ of Fig. 384. This operates the rotary and the vertical relays on the connector simultaneously and brings together for the first time the springs _21_ and _22_ of Fig. 396. This establishes a connection from the battery through the springs _16_ and _17_ on the calling battery supply relay, thence through the release magnet of the connector, thence through the springs _22_ and _21_ of the vertical and the rotary relay, thence through the release trunk back to the second selector. From here the circuit passes through the private wiper of that selector and the back release relay to ground through the third side switch wiper which is in the third position. Considering this circuit in respect to its action on the connector it is obvious that it energizes the release magnet on the connector which restores the connector to normal as before. At the second selector this circuit passed through the back release relay, which closed a circuit through the release magnet and through the back release relay contacts, thence back over the second selector release trunk to the back release relay of the first selector, and through the third wiper of the side switch on that selector to ground, since that side switch also is in its third position. The current through this circuit energizes the release magnet of the second selector and restores it to its normal position and also energizes the back release relay of the first selector. This, in turn, closes the circuit from the battery through the release magnet of the first selector and contacts of the back release relay to ground. This works the release magnet of the first selector and restores that selector to normal. The contacts on the first selector release magnet, shown in Fig. 390, are closed by the action of the release magnet and this closes the path from ground back through the first selector release wire, and through the contacts _13_ and _14_ of the line switch, through the line switch release magnet to battery, and this restores the line switch to normal. The reason for the term _back release_ will now be apparent. The release operation at the connector is relayed back to the second selector; that of the second selector back to the first selector; and that of the first selector back to the line switch. Until this plan was adopted, the release magnet of each selector and connector involved in a connection was left bridged across the talking circuit so as to be available for release; and it sometimes occurred that a first selector would be released before a second selector or connector, which latter switches would thus be left off-normal until rescued by an attendant. The back release plan makes it impossible for the connection necessary for the release of a switch to be torn down until the release is actually accomplished. Called Line Found Idle:--It will be remembered that, before the digression necessary to trace through the operations occurring upon the finding of a busy line, the connector wipers had been brought, by the influence of the calling subscriber's impulses, into engagement with the contacts of the desired line; that the connector side switch was in its second position; and that the final rotary impulse following the last series of selecting impulses had not been sent. The condition now to be assumed is that the called subscriber's line is free and the private wiper, therefore, has found and rests on an ungrounded private bank contact. The final rotary impulse which immediately follows will operate the rotary relay and this, in turn, will operate the private magnet. This happened under the assumed condition that the line was busy, but in that case the release magnet was also operated at the same time and restored all conditions to normal. Under the present condition the operation of the private magnet will perform its usual function and move the side switch of the connector into its third position. _Third Position of Side Switch._ When the side switch of the connector moves to its third position, it, as usual, cuts the talking circuit straight through from the vertical and the rotary sides of the trunk leading from the previous selector to the outgoing terminal of the subscriber's line, which may be traced upon Fig. 396 back through the line switch, shown in Fig. 389. Several things are to be noted about the talking circuit so established: First, the inclusion of the condensers in the vertical and the rotary sides of the connector circuit. The purpose of this will be referred to later. Second, the inclusion in this circuit at the connector of a pair of normally closed contacts in the ringing relay. It may be said in passing that the ringing relay corresponds exactly in function to a ringing key in a manual switchboard. Third, the talking circuit leading from the connector to the called subscriber's line passes on one side through the springs _24_ and _25_ of the bridge cut-off relay of the line switch, which is shown in Fig. 389. These springs are normally open and would prevent the completion of the talking circuit but for the fact that the bridge cut-off relay of the line switch is energized over the private wire leading to the connector bank and then through the connector wiper to the third side switch wiper which, at this time, is in its third position. The talking circuit is thus complete. The operation of this bridge cut-off relay on the line switch has not only completed the talking circuit but it has also opened the circuit of the trip magnet of the line switch so as to prevent the operation of the trip magnet by the subscriber on that line in case he should attempt to make a call during the interval between the time when his line was connected with by the connector and the time when he answers the call. The third wiper of the connector side switch when moved into its third position, puts the ground on all of the private bank contacts of the line chosen and thus guards that line against connection by others, as already described. It also operates the bridge cut-off relay of the line switch as just mentioned. The fourth wiper of the side switch, when moved into its third position, establishes such a connection as will place the ringing relay under the control of the vertical relay. This may be seen by tracing from ground to the vertical relay springs _23_ and _24_, thence through the normally closed upper pair of contacts on the private magnet, thence through the fourth wiper on the side switch to its third contact, thence through the ringing relay magnet, and through the springs _16_ and _17_ of the calling battery supply relay and to battery. The calling battery supply relay winding being in series with the vertical relay winding, the two operate together and close the two normally open points in the ringing relay circuit. This ringing relay acts as an ordinary ringing key and connects the generator to the called subscriber's line in an obvious manner, at the same time opening the talking circuit back of the ringing relay in order to prevent the ringing current chattering the relays in the circuit back of it. All that remains now is for the called subscriber to respond. When he does he closes the metallic circuit of the line through his talking apparatus. _Battery Supply to Connected Subscriber._ Throughout the whole process of building up a connection, it will be remembered that both sides of the calling line are connected through the respective vertical and rotary relays involved in building up the connection with the live side of the battery. At the time when the connection is finally established and the called subscriber rung, both sides of the calling line are connected through various relay windings to the live side of the battery. Such a condition leaves both sides of the line at the same potential and, therefore, there is no tendency for current to flow through the calling subscriber's talking apparatus, even though it is connected across the circuit of the line. It remains, therefore, to be seen how these conditions are so changed after the building up of a connection as to supply the calling subscriber with talking current. The calling subscriber can get no current until the called subscriber responds. When the connection is first made with the called subscriber's line, battery connection to his line is made from the live side of battery through the normally closed contacts of the calling battery supply relay, thence through the winding _25_ of the called battery supply relay to the vertical side of the called line. The grounded side of the battery is connected to the rotary side of his line through the third wiper of the connector and the coil _26_ of the called battery supply relay. As a result, this subscriber receives proper talking current through the coils _25_ and _26_, and this relay is operated by the flow of this current. The operation of this called battery supply relay merely shifts the connection of the rotary side of the calling subscriber's line from its normal battery connection, to ground, and thus the battery is placed straight across the calling subscriber's line so as to supply talking current. This supply circuit to the calling subscriber may be traced from the live side of the battery through the winding _13_ of the calling battery supply relay and the winding of the vertical relay to the vertical side of the line, and from the grounded side of battery through the third side switch wiper in its third position to the now closed pair of contacts in the called battery supply relay through the coil _18_ of the calling battery supply relay and the coil of the rotary relay to the rotary side of the line. It will be noted that the system of battery supply is that of the standard condenser and retardation coil scheme largely employed in manual practice; and that aside from the coils through which the battery current is supplied to the connected subscribers, there are no taps from, or bridges across, the two sides of the talking circuit. =Release after Conversation.= It remains now only to secure the disconnection of the subscribers after they are through talking. When the calling subscriber hangs up, the whole disconnection is brought about, all of the apparatus, including connector, selectors, and line switch, returning to normal. This is done by the back release system and is accomplished in almost the same way as has already been described in connection with the disconnect after an unsuccessful call. There is this difference, however: after an unsuccessful call when the line called for was found busy, the release was made while the connector side switch was in its normal position. In the present case, the release must be made with the connector side switch in its third position and with the talking battery bridged across the metallic circuit rather than connected between each limb of the line and ground. It must be remembered that the calling battery supply relay, while traversed by current during the conversation, is not magnetically energized because, with the current flowing through the metallic circuit of the line, the two windings exert a differential effect. As soon, however, as the calling subscriber hangs up his receiver, this differential action ceases, due to the grounding of both sides of the line at the subscriber's station. This relay, therefore, operates and cuts off battery from the called battery supply relay and this, in turn, releases its armature and thus changes the connection of the rotary side of the calling line from ground to live side of the battery. The normal condition of the battery connection now being restored, both the vertical and the rotary relays at the connector become operated, due to the ground on both sides of the line at the subscriber's station, and this, as we have seen, is the condition which brings about the operation of the connector release magnet, and the relaying back of the disconnect impulse successively through the selectors to the line switch. =Multi-Office System.= In exchanges involving more than one office, the same general principles and mode of operation already outlined apply. If the total number of subscribers in the multi-office exchange is to be less than ten thousand, then four digit numbers suffice, and the first movement of the dial may be made to select the office into which the connection is to go, the subscribers' lines being so numbered with respect to the offices that each office will contain only certain thousands. The choosing of the thousand by the calling subscriber, therefore, takes care in itself of the choice of offices. Where, however, a multi-office exchange is to provide for connections among a greater number of lines than ten thousand and less than one hundred thousand, then it will take five movements of the dial to make the selection--the five movements corresponding either to the five digits in a number or to the name of an office, as indicated on the dial, and the four digits of a smaller number. The lines may all carry five digit numbers or, what is considered better practice, may be designated by an office name followed by a four digit number. In this latter case the numbers of the subscribers' lines will in each case be contained in one or more of the tens of thousands groups, no number having more than four digits. And the first movement of the dial, whether the name or number plan be adopted, will select an office; or, looking at it another way, will select a group of ten thousand and this being done, the next four successive movements of the dial will select the numbers in that ten thousand in just the some way that has been already described. Certain difficulties arise, however, in multi-office working due to the fact that the three-wire trunks between offices would in most cases be objectionable. As long as the trunks extend between the various groups of apparatus in the same office, it is cheaper to provide three wires for each of them than it is to make any additional complication in the apparatus. Where the trunking is done between offices, however, the system may be so modified as to work over two wire inter-office trunks. _The Trunk Repeater._ The purpose of the trunk repeater is to enable the inter-office trunking to be done over two wires. It may be said that the trunk repeater is a device placed in the outgoing trunk circuit at the office in which a call originates, which will do over the two wires of the trunk leading from it to the distant office just the same thing that the subscriber's signal transmitter does over the two wires of the subscriber's lines. It has certain other functions in regard to feeding the battery for talking purposes back to the calling subscriber's line, taking the place in this respect of the calling battery feed relay in the connector in a single office exchange. [Illustration: Fig. 397. Circuits of Trunk Repeater] The circuits of a trunk repeater are shown in Fig. 397. In considering it, it must be understood that the three wires entering the figure at the left are the vertical, rotary, and release wires of a second selector trunk leading from the first selector banks in the same office. The two wires leading from the right of the figure are those extending to the distant office, and terminate there in second selectors. The vertical and the rotary sides of this trunk as shown at the left will receive the impulses from the subscriber's station coming through the line switch and the first selector, as usual. The vertical impulses will pass through the winding of the vertical relay and through the winding _1_ of the calling battery supply relay and thence to battery, the same as on a connector. These impulses will work the armatures of both of these relays in unison. The movements of the vertical relay armature in response to these impulses will cause corresponding impulses to flow over a circuit which may be traced from ground, through the springs _3_ and _2_ of the vertical relay, the springs _4_ and _5_ of the bridged relay _6_ and thence to the vertical side of the trunk and to the distant office, where it passes into a second selector and through its vertical relay to battery. Thus the vertical impulses are passed on over the two-wire trunk to the second selector at the distant office. It becomes necessary, however, to prevent these impulses from passing back through the winding of the bridge relay _6_ and this is done by means of the sluggish relay _7_. This relay receives local battery impulses in unison with those sent over the trunk by the vertical relay, these being supplied from the battery at the local office through the contacts _8_ and _9_ of the calling battery supply relay, which works in unison with the vertical relay. These rapidly recurring impulses are too fast for the sluggish relay _7_ to follow. And this relay merely pulls up its armature and cuts off both sides of the trunk leading back to the first selector. The rotary impulses are repeated to the rotary side of the two-wire trunk in a similar way. Considering now the operation of the trunk repeater in the reverse direction, the action of the bridging relay _6_ is of vital importance. Normally both sides of trunk line are connected to the live side of the battery and, therefore, there is no difference of potential between them and no tendency to operate the bridged relay. When the connection has been fully established to the subscriber at the distant office, and that subscriber has responded, the action of his battery supply relay will, as before stated, change the connection of the rotary side of the line from battery to ground, and thus bridge the battery at the distant exchange across the trunk. This action will pull up the bridged relay _6_ at the trunk repeater and will perform exactly the same function with respect to the connection of the battery with the calling subscriber's line. In other words, it will change the connection of the rotary side of the calling line from battery to ground, thus establishing the necessary difference in potential to give the calling subscriber the necessary current for transmission purposes. The disconnect feature is about the same as already described. When the calling subscriber hangs up his receiver both the vertical and rotary relays of the trunk repeater operate, which places the ground on both sides of the two-wire trunk to the distant office, which is the condition for releasing all of the apparatus there. For the purpose of convenience the simplified diagram of Fig. 398 has been prepared, which shows the complete connection from a calling subscriber to a called subscriber in a multi-office exchange, wherein the first movement of the dial is employed to establish the connection to the proper office and the four succeeding movements to make a selection among ten thousand lines in that office. This circuit, therefore, employs at the first office the line switch, the first selector, and the trunk repeater; and at the second office the second selector, third selector, connector, and line switch. The third selector is omitted from Fig. 398, but this will cause no confusion, since it is exactly like the second selector. The circuits shown are exactly like those previously described but in drawing them the main idea has been to simplify the connections to the greatest possible extent at a sacrifice in the clearness with which the mechanical inter-relation of parts is shown. No correct understanding of the circuits of an automatic system is possible without a clear idea of the mechanical functions performed by the different parts, and, therefore, we have described what are apparently the more complex circuit drawings first. It is believed that the student, in attempting to gain an understanding of this marvel of mechanical and electrical intricacy, will find his task less burdensome if he will refer freely to both the simplified circuit drawing of Fig. 398 and the more complex ones preceding it. By doing so he will often be enabled to clear up a doubtful circuit point from the simpler diagram and a doubtful mechanical point from those diagrams which represent more clearly the mechanical relation of parts. [Illustration: Fig. 398. Connection between a Calling and a Called Subscriber in an Automatic System] =Automatic Sub-Offices.= Obviously, the system of trunking employed in automatic exchanges lends itself with great facility to the subdivision of an exchange into a large number of comparatively small office districts and the establishment of branch offices or sub-offices at the centers of these districts. The trunking between large offices has already been described. An attractive feature of the automatic system is the establishment of so-called sub-stations or sub-offices. Where there is, in an outlying district, a distinct group of subscribers whose lines may readily be centered at a common point within that district and where the number of such subscribers and lines is insufficient to establish a fully equipped office, it is possible to establish a so-called sub-station or sub-office connected with the main office of that district by trunk lines. At this sub-office there are placed only line switches and connectors. When a call is originated on one of these sub-office lines, the line switch acts instantly to connect that line with one of the trunks leading to the main office of that district, at which this trunk terminates in a first selector. From there on, the connection is the same as that in a system in which no sub-offices are employed. Calls coming into this sub-office over trunk lines from the main office are received on the connectors at the sub-office and the connection is made with the sub-office line by the connector in the usual manner. This arrangement, it is seen, amounts merely to a stretching of the connector trunks for a given group of lines so that they will reach out from a main office to a sub-office, it being more economical to lengthen the smaller number of trunks and by so doing to decrease in length the larger number of subscribers' lines. =The Rotary Connector.= For certain purposes it becomes desirable in automatic work to employ a special form of connector which will have in itself a certain ability to make automatic selection of one of a group of previously chosen trunks in much the same manner as the first and second selectors automatically choose the first idle one of a group of trunks. Such a use is demanded in private branch-exchange working where a given business establishment, for instance, has a plurality of lines connecting its own private switchboard with the central office. The directory number of all these lines is, for convenience, made the same, and it is important, therefore, that when a person attempts to make a connection with this establishment, he will not fail to get his connection simply because the first one of these lines happens to be busy. For such use a given horizontal row of connector terminals or a part of such a row is assigned to the lines leading to the private branch exchange and the connector is so modified as to have a certain "discretionary" power of its own. As a result, when the common number of all these lines is called, the connector will choose the first one, if it is not already engaged by some other connector, but if it is, it will pass on to the next, and so on until an idle one is found. It is only when the connector has hunted through the entire group of lines and found them all busy that it will refuse to connect and will give the busy signal to the calling subscriber. =Party Lines.= The description of this system as given above has been confined entirely to direct line working; however, party lines may be and are frequently employed. The circuits and apparatus used with direct lines are, with slight modifications, applicable to use with party lines. The harmonic method of ringing is employed and the stations are so arranged with respect to the connectors that those requiring the same frequency for ringing the bells are in groups served by the same set of connectors. [Illustration: POWER MACHINERY Citizens' Telephone Company, Racine, Wis. _The Dean Electric Co._] The party lines are operated on the principle commonly known in manual practice as the jack per station arrangement. Each party line will, therefore, have sets of terminals appearing in separate hundreds; the connectors associated with each of these hundreds being so arranged as to impress the proper frequency of ringing current on the line. From the subscribers' standpoint the operation is the same as for direct lines, as the particular hundreds digit of a number serves to select one of a group of connectors capable of connecting the proper ringing current to the line. To avoid confusion, which would be caused by a subscriber on a party line attempting to make a call when the line is already in use by some other subscriber, the subscribers' stations are so arranged that when the line is in use all other stations on the line are locked out. [Illustration: Fig. 399. Wall Set for Two-Wire System] =The Two-Wire Automatic System.= The two-wire system that has recently been introduced by the Automatic Electric Company brings about the very important result of accomplishing all of the automatic switching over metallic circuit lines without the use of ground or common returns. The system is thus relieved of the disturbing influences to which the three-wire system is sometimes subjected, due to differences in earth potential between various portions of the system, which may add to or subtract from the battery potential and alter the net potential available between two distant points. The introduction of this system has also made possible certain other incidental features of advantage, one of which is a great simplification and reduction in size of the subscriber's station signal-transmitting apparatus. With the doing away of the ground as a return circuit, it becomes impossible to send vertical impulses over one side of the line and to follow them by single rotary impulses over the other side of the line. Yet it becomes necessary to distinguish between the pure selective impulses and those impulses which dictate a change of function at the central office. The plan has, therefore, been adopted of accomplishing the selection in each case by short and rapidly recurring impulses and of accomplishing those functions formerly brought about by the single impulse over the rotary side of the line by a pause between the respective series of selective impulses. This is accomplished at the central office by replacing the vertical and the rotary relays of the three-wire system by a quick-acting and a sluggish relay, respectively; the quick-acting relay performing the functions previously carried out by the vertical relay, and the sluggish relay acting only during the pauses between the successive series of quick impulses to do the things formerly done by the rotary relay. This has resulted in a delightful simplification of subscriber's apparatus, since it is now necessary only to provide a device which will connect the two sides of the line together the required number of times in quick succession and then allow a pause with the circuit closed while the subscriber is getting ready to transmit another set of impulses corresponding to another digit. The calling device has no mechanical function co-acting with any of the other parts of the telephone and may be considered as a separate mechanical device electrically connected with the line. The transmitting device is not much larger than a large watch and a good idea of it may be had from Fig. 399, which shows the latest wall set, and Fig. 400, which shows the latest desk set of the Automatic Electric Company. We regret the fact that this company has made the request that the complete details of their two-wire system be not published at this time. [Illustration: Fig. 400. Desk Stand for Two-Wire System] CHAPTER XXX THE LORIMER AUTOMATIC SYSTEM The Lorimer automatic telephone system has not been commercially used in this country but is in commercial operation in a few places in Canada. It is interesting from several points of view. It was invented, built, and installed by the Lorimer Brothers--Hoyt, George William, and Egbert--of Brantford, Ontario. These young men without previous telephonic training and, according to their statements, without ever having seen the inside of a telephone office, conceived and developed this system and put it in practical operation. With the struggles and efforts of these young men in accomplishing this feat we have some familiarity, and it impresses us as one of the most remarkable inventive achievements that has come to our attention, regardless of whatever the merits or demerits of the system may be. The Lorimer system is interesting also from the fact that, in most cases, it represents the mechanical rather than the electrical way of doing things. The switches are power driven and electrically controlled rather than electrically driven and electrically controlled, as in the system of the Automatic Electric Company. The subscriber's station apparatus consists of the usual receiver, speech transmitter, call bell, and hook switch, and in addition a signal transmitter arranged to be manipulated by the subscriber so as to control the operation of the central-office apparatus in connecting with any desired line in the system. The central-office apparatus is designed throughout upon the principle of switching by means of power-driven switches which are under the control of the signal transmitters of the calling subscriber's station. The switches employed in making a connection are all so arranged with respect to constantly rotating shafts that the movable member of such switches may be connected to the shafts by means of electromagnets controlled directly or indirectly by relays, which, in turn, are brought under the control of the signal transmitters. The circuits are so designed in many instances that the changes necessary for the different steps are brought about by the movement of the switches themselves, thus permitting the use of circuits which are rather simple. The switches employed are all of a rotary type; the co-ordinate selection, which is accomplished in the Automatic Electric Company's system by a vertical and rotary movement, being brought about in this system by the independent rotation of two switches. =Subscriber's Station Equipment.= A subscriber's desk-stand set, except the call bell, is shown in Fig. 401, and a wall set complete in Fig. 402. In both of these illustrations may be seen the familiar transmitter, receiver, and hook switch, and in the wall set, the call bell. The portion of these telephone sets which is unfamiliar at present is the part which is enclosed in the enlarged base of the desk stand and the protruding device below the speech transmitter in the wall set--the signal transmitter referred to earlier in the chapter. The small push button and small plate through which the number may be seen directly below the transmitter in Fig. 402, are for the purpose of registering calls. [Illustration: Fig. 401. Lorimer Automatic Desk Stand] The signal transmitter is a device whose function is to record mechanically the number of the subscriber's station with which connection is desired, and to transmit that record to the central office by a system of electrical impulses over the line conductors. Instead of operating by its own initiative, the signal transmitter is adapted to respond to central-office control in transmitting electrically the number which has been recorded mechanically upon it. The signal transmitter shown removed from the base of the desk stand at the left in Fig. 403 comprises in part four sets of contact pins having ten pins in each set, one set for each of the digits of a four-digit number. There are also several additional contact pins for signaling and auxiliary controlling purposes. All of these contact pins are arranged upon the circumference of a circle and a movable brush mounted upon a shaft at the center of the circle is adapted to be rotated by a clock spring and to make contact with each of the pins successively. The call is started, after the number desired has been set on the dial, by giving the crank at the right of the signal transmitter a complete turn and thus winding the spring. The shaft carrying the signal transmitter brush carries also an escapement wheel, the pallet of which is directly controlled by an electromagnet. [Illustration: Fig. 402. Lorimer Automatic Wall Set] The four dials with the numerals printed on them are attached to four levers, respectively, and are moved by their levers opposite windows, near the top of the casing. Through each of these windows a single numeral may be seen on the corresponding one of the dials. The dials may be adjusted so that the four numerals seen will read from left to right to correspond to the number of the line with which connection is desired. The setting of the dials so that the number desired shows at the small circular opening results in connecting the earth or a common return conductor to one pin of each set of ten pins, the pin grounded in each set depending upon the numerical value of the digit for which the dial is set. The circle of contact pins is set in an insulating disk, the signal transmitting brush operates upon the pins on one side of the disk, and electrical fingers attached to the dials operate upon the pins on the other side of the disk. The escapement wheel is a single toothed disk attached directly to the shaft which carries the signal brush and its pallet is attached rigidly to the magnet armature. [Illustration: Fig. 403. Desk Stand with Signal Transmitter Removed] Once a call has been turned in, the entire subscriber's station equipment is locked beyond power of the subscriber to tamper with it in any way, rendering it impossible either to defeat the call which has been started or to prevent the subscriber's station as a whole from returning completely to normal position and thus restoring itself for regular service. The key shown just below the signal transmitter in the case of the desk stand, and at the right in the wall set, is for the purpose of operating a relay at the central office which, in turn, connects ringing current to the line of the subscriber with which connection has been made, and thus actuates the call bell. As the number set up at the signal transmitter remains in full view until reset for some other number, it is easily checked by inspection and also lessens the labor involved in making a second call for the same line, which is frequently necessary when the line is found busy the first time called. =Central-Office Apparatus.= The subscriber's lines are divided into groups of one hundred lines each at the central office, each group being served by a single unit of central-office apparatus. In a central-office unit there is "sectional apparatus" which appears but once for the unit of one hundred lines; "divisional apparatus" which appears a number of times for each unit, depending upon the traffic; and "line apparatus" which appears one hundred times for each unit or once for each line. The sectional apparatus comprises devices whose duties are, first, to detect a calling line, and second, to assign to the calling line a set of idle divisional apparatus which serves to perform the necessary switching functions and complete the connection. The sets of divisional apparatus, or, as called in this system, "divisions," are common to a section and are employed in a manner similar to the connecting cords of a manual switchboard. The number of these divisions provided for each section is, therefore, determined by the number of simultaneous connections resulting from calls originating in the section. It has been the custom in building this apparatus to provide each section with seven divisions or connective elements. The line apparatus comprises one relay, having a single winding, and two pairs of contacts operated by its armature. This device is substantially the well known cut-off relay almost universally employed in common-battery systems. The fixed multiple contacts of the lines in the switching banks of the connecting apparatus are considered as pertaining to the various pieces of apparatus on which they are found rather than to their respective lines. A good idea may be obtained of the arrangement of the sectional and divisional apparatus by referring to Fig. 404, which is one unit of a thousand-line equipment. The apparatus in the vertical row at the extreme left of the illustration is the sectional apparatus, while the remaining seven vertical rows of apparatus are the divisions. _The Section._ The sectional apparatus for each unit consists of three separate devices called for convenience a _decimal indicator_, a _division starter_, and a _decimal-register controller_. All of these devices are normally motionless when idle. The energization of the decimal indicator, in response to the inauguration of a call at a subscriber's station, results immediately in an action of the division starter which starts a division to connect with the line calling. It results also in the starting of the decimal-register controller, the remaining unit of sectional apparatus. It is thus seen that upon the starting of a call by a subscriber, all of the sectional apparatus belonging to his one hundred lines immediately becomes active, the division starter acting to start a division, the decimal indicator becoming energized to indicate the tens group in which the call has appeared, and the decimal-register controller becoming active to adjust the decimal register of the division assigned by the division starter. The division starter having assigned a division for the exclusive use of this particular call, passes to a position from which it may start a similar idle division when the next call is received. The decimal register controller makes its half revolution for the call and comes to rest, awaiting a subsequent call, and the decimal indicator continues energized but only momentarily, since it is released by the action of the cut-off relay when the call is taken in charge by the divisional connective devices. Calls may follow each other rapidly, the connective devices being entirely independent of each other after having been assigned to the respective calling lines. As has been described, the decimal indicator starts the division starter and the decimal-register controller in quick succession. The division starter, shown at the extreme bottom of the left-hand row of Fig. 404, is a cylinder switch of the same general type as used throughout this system. In it the terminals of a switch in each division appear as fixed contact points in a circle over which move the brushes of the division starter. The decimal-register controller has the duties of transmitting to the divisional apparatus a series of current impulses corresponding in number to the numerical value of the tens digit of the calling line. This is effected by providing before a movable brush ten contacts from which the brush may receive current. These contacts are normally not connected to battery, so that the brush in passing over them does not receive current from them; however, when the brush has reached the contact corresponding in number to the tens digit of the calling line, a relay associated with the decimal-register controller charges the contacts with the potential of the main battery, and each of the remaining contacts passed over by the brush sends a current impulse to a device designed to indicate on the division selected for the call the tens digit of the calling line. _The Connective Division._ The connective division, seven of which are shown in Fig. 404, is an assemblage of switches comprising, as a whole, a set suitable for a complete connection from calling to called subscriber. Each connective division in the unit illustrated is completely equipped to care for a called number of three digits, _i. e._, each division will connect its calling line with any one of one thousand lines which may be called. By a system of interconnecting between divisions, each division may be equipped with interconnecting apparatus so as to make it possible to complete a call with any one of ten thousand lines. Each connecting division of a ten-thousand-line exchange comprises six major switches. Of the six major switches, one is termed a _secondary connector_, another an _interconnector_, and the four remaining are termed the _primary portion_ of the division. [Illustration: Fig. 404. Unit of Switching Apparatus] Before taking up the operation of the switches, the mechanical nature of the switches themselves will be described. The switches are built with a contact bank cylindrical in form and with internal movable brushes traveling in a rotary manner in circular paths upon horizontal rows of contacts fixed in the cylindrical banks. For driving these brushes a constantly rotating main power-driven shaft is provided. Between each shaft and the rotating brushes of each major switch is an electric clutch, which, by the movement of an armature, causes the brushes of the switch to partake of the motion of the shaft and by the return of the armature to come again to rest. The motion of the brushes of the major switches, or cylinder switches, as they are frequently called because of their form, is constantly in the same direction. They have a normal position upon a set of the cylinder contacts. They leave their normal position and take any predetermined position as controlled by the magnets of the clutch, and, having served the transient purpose, they return to their normal position by traversing the remainder of their complete revolution and stopping in their position of rest or idleness. The mechanical construction of each of the cylinder switches is such that it may disengage its clutch and bring its brushes to rest only with the brushes in some one of a number of predetermined positions. The locations of the brushes in these positions of rest, or "stop" positions, as they are called, may differ with the different cylinder switches, according to the nature of the duty required of the switch, and the total number of stop positions also may vary. The primary and secondary connectors, the interconnector selectors, and the interconnectors each have eleven stop positions; the rotary switch has eight stop positions; the signal-transmitter controller has but two. In the six cylinder switches making up a connective division and required for any conversation, in a ten-thousand-line exchange some of the switches are set to positions which are determined by the control of the calling subscriber and represent by their selective positions the value of some digit of the calling or called subscriber's number. Others are switches controlling the call in its progress and controlling the switches responsive to the call. These latter switches take positions independent of the numbers. In addition to the major switches, there are upon each division four minor switches termed _registers_. Each consists of an arc of fixed contacts accompanied by a set of brushes which sweep over the contacts. Instead of being driven by an electromagnet, the register brushes are placed under tension of a spring which tends at all times to draw them forward. They are then restrained by an escapement device similar to a pallet escapement in a clock, the pallet being controlled by the register's magnets. When a series of impulses are received by the register magnets, the pallet is actuated a corresponding number of times and the register brushes are permitted to move forward under tension of their powerful propelling spring. Each register is associated with a major switch, and the register brushes are engaged by a cam upon the associated major switch, and are restored to normal position against the tension of their propelling spring, the force of restoration being obtained from the main shaft. The electrical clutches which connect and disconnect the movable brushes of the major switches from the main driving shaft are controlled in all instances by circuits local to the central office. In some instances these circuits include relay contacts and are controlled by a relay. In other instances they are formed solely through switch contacts. In all cases the control, when from a distance, is received upon relays suitable for being controlled by the small currents which are adapted to flow over long lines. In all instances the power for moving a brush is derived from the main shaft and only the control of the movement is derived from electromagnets, relays, or other electric sources. In many instances the clutch circuit is closed through contacts of its own switch and, therefore, may be closed only when its switch is in some predetermined position. All of the switches are mechanically powerful and designed particularly to sustain the wear of long-continued and oft-repeated usage. This is true also of the moving parts which carry the brushes and of the journals sustaining those parts. _The Switches of the Connective Division._ The six major switches of the connecting division are as follows: The Primary Connector:--The function of this switch is to connect the conductors of the calling line with the switching devices of the connective division. Associated with this switch is a register termed the _decimal register_. The one hundred lines of the section are terminated in fixed multiple contacts in the cylinder switch of the primary connector. The calling line is selected and connected with by adjusting the decimal register to a position corresponding to the calling line's tens digit and adjusting the brushes of the cylinder switch to a position corresponding to the calling line's unit digit. The Rotary Switch:--This is a master switch, or pilot switch, consisting of a cylinder switch without register. Its duty is the control of other switches and the completion of circuits formed in part through other switches. It is the pilot switch and the switch of initiative and control for the entire connective division. Signal-Transmitter Controller:--The primary function of this switch is the generation of signaling impulses of two classes. Impulses of the first class pass over central-office circuits only and are effective upon magnets of the divers major and minor switches; impulses of the second class pass over a line conductor of the calling line and are effective upon the signal transmitter at the subscriber's station. The impulses sent out over the line to the subscriber's station cause the brush to pass over the contacts and thereby indicate the numerical values of the various digits set by the dials. This switch also enters in an important manner into the circuits involved in the testing of the called line for the busy condition. It is controlled by the rotary switch. Interconnector Selector:--In an exchange using four digits in the numbers, the register of the interconnector selector is adjusted in each call to a position corresponding to the numerical value of the thousands digit of the called number. The cylinder switch then acts to select an idle trunk. The switch is controlled by the rotary switch in connection with the signal transmitter controller. Interconnector:--This switch is similar to the interconnector selector in design and in function. It is a cylinder switch with register. The register is adjusted in each call to a position corresponding to the numerical value of the hundreds digit of the number called and the cylinder switch then operates to select an idle trunk. The switch is controlled by the rotary switch in connection with the signal transmitter controller. Secondary Connector:--This switch contains in its cylinder bank of contacts the multiple points of one hundred subscribers' lines and its function is to connect the conductors of the called line to the conductors of the connective division. This is accomplished by adjusting the register to correspond to the value of the tens digit of the line desired and by adjusting the cylinder brushes to correspond to the value of the units digit of the line. The switch is controlled by the rotary switch in connection with the signal-transmitter controller. =Operation.= A brief description of the progress of a call from its institution to the complete connection and subsequent disconnection begins with the adjustment of the dial indicators of the telephone set and the turning of the crank of the signal transmitter one revolution. This act, performed by the calling subscriber, connects one of the line conductors to earth. Immediately the decimal indicator associated with the section in which the calling line terminates is energized and starts the division starter. The division starter instantly starts the rotary switch of an idle division. The rotary switch now starts the decimal-register controller and connects to it the decimal register of the primary connector of the division selected. All of the above acts in the central office occur practically simultaneously. The impulses generated by the controller are effective upon the decimal register of the started division and, therefore, adjust that register to a position corresponding to the tens value of the calling line. The rotary switch now disconnects the tens register and starts the cylinder brushes of the primary connector which automatically stop when they encounter the calling line. At this instant the cut-off relay of the line is energized and the decimal indicator is released. The call now is clear of all sectional apparatus and another call may come through immediately, being assigned in charge of another idle division. The total time in which any call is in charge of the sectional apparatus, _i. e._, the total time from the grounding of the line conductor at the sub-station until the line has been connected with by the primary connector of some division of that section and the sectional apparatus has been released by the operation of the cut-off relay, approximates two-fifths of a second. The next operation initiated by the rotary switch is the starting of the signal-transmitter controller of the connective division, which, in turn, adjusts the register of the interconnector selector to a position corresponding to the thousands digit of the number of the called line as indicated by the signal transmitter at the calling station. This selects an interconnector serving the lines of the selected thousand. This initial selection being completed the rotary switch readjusts the circuits of the connective division in such manner that in the further progress of the signal-transmitter controller, its impulses will be effective upon the register of the selected interconnector. In this manner, the register of the interconnector, which may be upon the same connective division as the rotary switch handling the call, or which may be the interconnector of some other division, as determined by the number of the called subscriber, is adjusted to a position corresponding to the second or hundreds digit of the number called. The cylinder switch of the interconnector then selects and appropriates an idle trunk extending to a secondary connector upon some connective division serving the hundred selected. The rotary switch again shifts the circuits of the connective division in such manner that the signal-transmitter controller is effective upon the secondary connector, both register and cylinder, and adjusts the register and cylinder, respectively, with their brushes in contact with the tens and units digits, respectively, of the number of the called line. The conductors of the called line now are connected through the secondary connector, the interconnector, and the interconnector selector to the rotary switch; the conductors of the calling line are connected through the primary connector to the rotary switch; thus completely connecting the lines except at the rotary switch. To effect the connecting together of the two lines, both rotary switch and signal-transmitter controller must pass forward into their next positions, the connection when thus effected being made through conductors containing a repeating coil and main battery connection for supplying talking current to the two lines and containing also ringing and supervisory relays. The called line is tested to determine if busy during the short interval in which the rotary switch takes a short step to connect the calling and the called lines. In this step of the rotary switch the busy-test relay is connected to the guard wire or busy-test wire of the called line, and if that line be busy, the relay interferes with the control exercised by the rotary switch upon the signal-transmitter controller, and the controller is prevented from taking the step required to connect the line. Thus, when a busy line is encountered, the final step of the rotary switch is taken to set up the conversation conditions, but the signal-transmitter controller does not take its final step; by this failure of the signal-transmitter controller due to the action of the busy-test relay, the calling line is not connected to the called line but is connected to a busy-back tone generator instead. Whether the line encountered be busy or idle, the connective division remains in its condition as then adjusted until the subscriber hangs his receiver upon the hook switch to obtain disconnection. The ringing of the bell of the called station is done directly by the calling subscriber in pressing the ringing key. The disconnection is effected, when the receiver of the calling line is hung up, by the supervisory relay in the central office, whose winding is included in the line circuit, and whose contacts act directly to start the rotary switch. In disconnecting, the rotary switch starts the primary and the secondary connectors and thus instantly releases both the calling and the called lines. Thereafter the rotary switch in passing from position to position restores switch after switch of the connective division to normal and finally itself returns to normal in preparation for its assignment to service in answering a subsequent call. CHAPTER XXXI THE AUTOMANUAL SYSTEM Two systems of telephony are now in common use in this country--the manual system and the automatic. With the growth of the automatic, and the gradually ripening conviction, which is now fully matured in the minds of most telephone engineers, that automatic switching is practical, there has been a growing tendency toward doing automatically many of the things that had previously been done manually. One of the results of this tendency has been the production of the _automanual_ system, the invention of Edward E. Clement, an engineer and patent attorney, of Washington, D. C. In connection with Mr. Clement's name, as inventor, must be mentioned that of Charles H. North, whose excellent work as a designer and manufacturer has contributed much toward the present excellence of this highly interesting system. =Characteristics of System.= The name "automanual" is coined from the two words, automatic and manual, and is intended to suggest the idea that the system partakes in part of the features of the automatic system and in part of those of the manual system. We regret that neither space nor the professional relation which we have had with the development of this system will permit us to make public an extended and detailed description of its apparatus and circuits. Only the general features of the system may, therefore, be dealt with. [Illustration: POWER APPARATUS FOR COMMON-BATTERY MANUAL OFFICE OF MEDIUM SIZE] The underlying idea of the automanual system is to relieve the subscriber of all work in connection with the building up of his connection, except the asking for it; to complicate the subscriber's station equipment in no way, it being left the same as in the common-battery manual system; to do away with manual apparatus, such as jacks, cords and plugs, at the central office, and to substitute for it automatic switching apparatus which will be guided in its movements, not by the subscriber, but by a very much smaller number of operators than would be necessary to manipulate a manual switchboard. =General Features of Operation.= A broad view of the operation of the system is this. The subscriber desiring to make a call takes down his receiver, and this causes a lamp to light in front of an operator. The operator presses a button and is in telephonic communication with the subscriber. Receiving the number desired, the operator sets it up on a keyboard in just about the same way that a typist will set up the letters of a short word on a typewriting machine. The setting up of the number on the keyboard being accomplished, the proper condition of control of the associated automatic apparatus at the central office is established and the operator has no further connection with the call. The automatic switching apparatus guided by the conditions set up on the operator's keyboard proceeds to make the proper selection of trunks and to establish the proper connections through them to build up a talking circuit between the calling subscriber and the called and to ring the called subscriber's bell, or, if his line is found busy, the apparatus refuses to connect with it and sends a busy signal back to the calling subscriber. The operator performs no work in disconnecting the subscribers, that being automatically taken care of when they hang up their receivers at the close of the conversation. From the foregoing it will be seen that there is this fundamental difference between the automatic and the automanual--the automatic system dispenses entirely with the central-office operator for all ordinary switching functions; the automanual employs operators but attempts to so facilitate their work that they may handle very many more calls than would be possible in a manual system, and at the same time secures the advantages of secrecy which the automatic system secures to its subscribers. =Subscriber's Apparatus.= One of the main points in the controversy concerning automatic _versus_ manual systems is whether or not it is desirable to have the subscriber ask for his connection or to have him make certain simple movements with his fingers which will lead to his securing it. The developers of the automanual system have taken the position that the most desirable way, so far as the subscriber is concerned, is to let him ask for it. It is probable that this point will not be a deciding one in the choice of future systems, since it already seems to be proven that the subscribers in automatic systems are willing to go through the necessary movements to mechanically set up the call. The advantage which the automanual system shares with the manual, however, in the greater simplicity of its subscriber's station apparatus, cannot be gainsaid. [Illustration: Fig. 405. Operators' Key Tables] [Illustration: Fig. 406. Top View of Key Table] =Operator's Equipment.= The general form of the operator's equipment is shown in Fig. 405. A closer view of the top of one of the key tables is shown in Fig. 406. As will be seen, the equipment on each operator's position consists of three separate sets of push-button keys closely resembling in external appearance the keys of a typewriter or adding machine. Immediately above each set of keys are the signal lamps belonging to that set. The operator's keys are arranged in strips of ten, placed _across_ rather than _lengthwise_ on the key shelf. One of these strips is shown in Fig. 407. There are as many strips of keys in each set as there are digits in the subscribers' numbers, _i. e._, three in a system having a capacity of less than one thousand; four in a system of less than ten thousand; and so on. In addition to the number keys of each set is a partial row of keys, including what is called a _starting key_ and also keys for making the party-line selection. [Illustration: Fig. 407. Strip of Selecting Keys] [Illustration: Fig. 408. Wiring of Key Shelf] The simplicity of the operator's key equipment is one of its attractive features. Fig. 408 shows one of the key shelves opened so as to expose to view all of the apparatus and wiring that is placed before the operator. The reason for providing more than one key set on each operator's position is, that after a call has been set up on one key set, a few seconds is required before the automatic apparatus controlled by the key set can do its work and release the key set ready for another call. The provision of more than one key set makes it possible for the operator to start setting up another call on another key set without waiting for the first to be released by the automatic apparatus. [Illustration: Fig. 409. Switch Room of Automanual Central Office] =Automatic Switching Equipment.= A general view of the arrangement of automatic switches in an exchange established by the North Electric Company at Ashtabula, Ohio, is shown in Fig. 409. The desk in the foreground is that of the wire chief. This automatic apparatus consists largely of relays and automatic selecting switches. The switches are of the step-by-step type, having vertical and rotary movements, and an idea of one of them, minus its contact banks, is given in Fig. 410. The control of the automatic switches by the operator's key sets is through the medium of a power-driven, impulse-sending machine. From this machine impulses are taken corresponding to the numbers of the keys depressed. [Illustration: Fig. 410. Selecting Switch] =Automatic Distribution of Calls.= A feature of great interest in this system is the manner in which the incoming calls are distributed among the operators. From each key set an operator's trunk is extended to what is called a secondary selector switch, through which it may be connected to a primary selector trunk and calling line. When a subscriber calls by taking down his receiver, his line relay pulls up and causes a primary selector switch to connect his line with an idle local trunk or link circuit, at the same time starting up a secondary selector switch which immediately connects the primary trunk and the calling line to an operator's idle key set. If an operator is at the time engaged in setting up a call on a key set, or if that key set is still acting to control the sending of impulses to the automatic switches, it may be said to be busy, and it is not selected by this preliminary selecting apparatus in response to an incoming call. As soon, however, as the necessary impulses have been taken from the key set by the automatic apparatus, that key set is released and is again ready to receive a call. In this way the calls come before each operator only as that operator is able and ready to receive them. =Setting up a Connection.= As soon as the key-set lamp lights, in response to such an incoming call, the operator presses a listening button, receives the number from the subscriber, and depresses the corresponding number buttons on that key set, thereby determining the numbers in each of the series of impulses to be sent to the selector and the connector switches to make the desired connection. The operator repeats this number to the calling subscriber as she sets it up, and then presses the starting button, whereupon her work is done so far as that call is concerned. If, upon repeating the call to the subscriber, the operator finds that she is in error, she may change the number set up at any time before she has pressed the starting button. =Building up a Connection.= The keys so set up determine the number of impulses that will be transmitted by the impulse-sending machine to the selector and the connector switches. These switches, impelled by these impulses, establish the connection if the line called for is not already connected to. If a party-line station is called for, the proper station on it will be selectively rung as determined by the party-line key depressed by the operator. If the line is found busy, the connector switch refuses to make the connection and places a busy-back signal on the calling line. =Speed in Handling Calls.= This necessarily brief outline gives an idea only of the more striking features of the automanual system. A study of the rapidity with which calls may be handled in actual practice shows remarkable results as compared with manual methods of operating. The operators set up the number keys corresponding to a called number with the same rapidity that the keys of a typewriter are pressed in spelling a word. In fact, even greater speed is possible, since it is noticed that the operators frequently will depress all of the keys of a number at once, as by a single striking movement of the fingers. The rapidity with which this is done defies accurate timing by a stop watch in the hands of an expert. It is practically true, therefore, that the time consumed by the operator in handling any one call is that which is taken in getting the number from the subscriber and in repeating it back to him. TABLE XI Total Time Consumed by Operator in Handling Calls on Automanual System +-----------------------------------------------------------------+ | First 100 Calls | +-----------------------------------------------------------------+ |Longest Individual Period 12.40 seconds | |Average five longest Individual Periods 7.44 seconds | |Average ten longest Individual Periods 6.34 seconds | |Shortest Individual Period 1.60 seconds | |Average five shortest Individual Periods 1.92 seconds | |Average ten shortest Individual Periods 1.96 seconds | |Average Entire 100 Calls 3.396 seconds | |Hourly Rate at which calls were being handled 1060 | +-----------------------------------------------------------------+ +-----------------------------------------------------------------+ | Second 100 Calls | +-----------------------------------------------------------------+ |Longest Individual Period 7.60 seconds | |Average five longest Individual Periods 5.52 seconds | |Average ten longest Individual Periods 5.34 seconds | |Shortest Individual Period 2.00 seconds | |Average five shortest Individual Periods 2.04 seconds | |Average ten shortest Individual Periods 2.18 seconds | |Average Entire 100 Calls 3.374 seconds | |Hourly Rate at which calls were being handled 1067 | +-----------------------------------------------------------------+ +-----------------------------------------------------------------+ | Third 100 Calls | +-----------------------------------------------------------------+ |Longest Individual Period 5.40 seconds | |Average five longest Individual Periods 5.32 seconds | |Average ten longest Individual Periods 4.44 seconds | |Shortest Individual Period 1.60 seconds | |Average five shortest Individual Periods 1.65 seconds | |Average ten shortest Individual Periods 1.80 seconds | |Average Entire 100 Calls 3.160 seconds | |Hourly Rate at which calls were being handled 1139 | +-----------------------------------------------------------------+ Owing to the difficulty of securing accurate traffic data by means of a stop watch, an automatic, electrical timing device, capable of registering seconds and hundredths of a second, has been used in studying the performance of this system in regular operation at Ashtabula Harbor. The operators were not informed that the records were being taken, and the data tabulated represents the work of two operators in handling regular subscribers' calls. The figures in Table XI are given by C. H. North as representing the total time consumed by the operator from the time her line lamp was lighted until her work in connection with the call was finished, and it included, therefore, the pressing of the listening button, the receiving of the number from the subscriber, repeating it back to him, setting up the connection on the keys, and pressing the starting key. It will be seen that the average time for each 100 calls is quite uniform and is slightly over three seconds. The considerable variation in the individual calls, ranging from a maximum of 12.40 seconds down to a minimum of 1.60 seconds, is due almost entirely to the difference between the subscribers in the speed with which they can give their numbers. These figures indicate that, in each of the tests, calls were being handled at the rate of more than one thousand per hour by each operator. The test of the subscriber's waiting time, _i. e._, the time that he waited for the operator to answer, for one hundred calls made without the knowledge of the operator, showed the results as given in Table XII, in which a split second stop watch was used in making the observations. TABLE XII Subscribers' Waiting Time +----------------------------------------------------------+ |Number of Calls Tested 100 | |Longest Individual Period 5.20 seconds | |Average 5 Longest Individual Periods 4.64 seconds | |Average 10 Longest Individual Periods 3.80 seconds | |Shortest Individual Period 1.00 seconds | |Average 5 Shortest Individual Periods 1.28 seconds | |Average 10 Shortest Individual Periods 1.34 seconds | |Average Entire 100 Calls 2.07 seconds | +----------------------------------------------------------+ The length of time which the subscriber has to wait before receiving an answer from the operator is, of course, one of the factors that enters into the giving of good telephone service, and the times shown by this test are considerably shorter than ordinarily maintained in manual practice. The waiting time of the subscriber is not, of course, a part of the time that is consumed by the operator, and the real economy so far as the operator's time is concerned is shown in the tests recorded in Table XI. CHAPTER XXXII POWER PLANTS The power plant is an organization of devices to furnish to a telephone system the several kinds of current, at proper pressures, for the performance of the several general electrical tasks within the exchange. =Kinds of Currents Employed.= Sources of both direct and alternating current are required and a single exchange may employ these for one or more of the following purposes: _Direct Current._ Current which flows always in one direction whether steady or varying, is referred to as direct current, and may be required for transmitters, for relays, for line, supervisory, and auxiliary signals, for busy tests, for automatic switches, for call registers, for telegraphy, and in the form of pulsating current for the ringing of biased bells. _Alternating Current._ Sources of alternating current are required for the ringing of bells, for busy-back and other automatic signals to subscribers, for howler signals to attract the attention of subscribers who have left their receivers off their hooks, and for signaling over composite lines. =Types of Power Plants.= Clearly the requirements for current supply differ greatly for magneto and common-battery systems. There is, however, no great difference between the power plants required for the automatic and the manual common-battery systems. In the simplest form of telephone system--two magneto telephones on a private line--the power plant at each station consists of two elements: one, the magneto generator, which is a translating device for turning hand power into alternating current for ringing the bell of the distant station; and the other, a primary battery which furnishes current to energize the transmitter. In such a system, therefore, each telephone has its own power plant. The term power plant, however, as commonly employed in telephone work, refers more particularly to the organization of devices at the central office for furnishing the required kinds of current, and it is to power plants in this sense that this chapter is devoted. _Magneto Systems._ If magneto lines be connected to a switchboard, the current for throwing the drop at the switchboard is furnished by the subscriber's generator, and the current for energizing the subscriber's transmitter is furnished by the local battery at his station; but sources of current must be provided for enabling the central-office operator to signal or talk to the subscribers. These are about the only needs for which current must be furnished in an ordinary magneto central office. If a multiple board is employed, direct current is also needed for the purpose of the busy test and also for operating the drop restoring circuits, if the electrical method of restoring the drops is employed. _Common-Battery Systems._ In common-battery systems the requirements are very much more extensive. The subscribers' telephones have no power plants of their own, but are provided with a common source of direct current located at the central office for supplying the talking current, and for operating the central-office signals, and the operators are provided with one or more common sources of alternating or pulsating current for ringing the subscribers' bells. Common-battery equipment requires the use of currents of different kinds for a greater number of auxiliary purposes than does magneto equipment. These facts make the power plant in a common-battery office much more important than in a magneto office. =Operators' Transmitter Supply.= In a small magneto exchange, the transmitter current may be had from primary batteries, a separate battery being employed for each operator's set. When there are more than three or four operators, however, it is usual, even in magneto offices, to obtain the transmitter current from a common storage battery. A storage battery has the fortunate quality of very low internal resistance, therefore a number of operators' transmitters may be actuated by one source without introducing cross-talk. In other words, a storage battery is a current-furnishing device of good regulation, the variation of consumption in one circuit leading from it causing slight variation in the currents of other circuits leading from it. If this were not so, cross-talk would exist between the telephones of the operators' positions connected to the same battery. This regulating quality enables the multiple feeding of telephone circuits to be carried further than the mere supplying of operators' sets and is the quality which makes possible the successful use of a storage battery as the single source of transmitter current for common-battery central-office equipment. In furnishing a plurality of operators' transmitters from a common battery, the importance of low resistance and inductance in the portion of the path that is common to all of the circuits must not be overlooked. Not only is a battery of extremely low resistance required, but also conductors leading from it that are common to two or more of the circuits should be of very low resistance and consequently large in cross-section and as short as possible. In common-battery offices there is obviously no need of employing a separate battery for the operators' transmitters, since they may readily be supplied from the common storage battery which supplies direct current to the subscribers' lines. =Ringing-Current Supply.= _Magneto Generators._ As a central-office equipment is required to ring many subscribers' bells, only the small ones find it convenient to ring them by means of hand-operated magneto generators. Small magneto switchboards are usually equipped so that each operator is provided with a hand-generator, but even where such is the case some source of ringing current not manually operated is desirable. In larger switchboards the hand generators are entirely dispensed with. The magneto generator may be driven by a belt from any convenient constantly moving pulley, and the early telephone exchanges were often equipped with such generators having better bearings and more current capacity than those in magneto telephones. These were adapted to be run constantly from some source of power, delivering ringing current to the operators' keyboards at from 16 to 20 cycles per second. _Pole Changers._ Vibrating pole changers were also used in the early exchanges, but passed out of use, partly because of poor design, but more because of the absence of good forms of primary batteries for vibrating them and for furnishing the direct currents to be transformed into alternating line current for ringing the bells. The pole changer was redesigned after the beginning of the great spread of telephony in the United States in 1893. Today it is firmly established as an element of good telephone practice. Fig. 411 illustrates the principle upon which one of the well-known pole changers--the Warner--operates. In this _1_ is an electromagnet supplied by a constant-current battery _2_ to keep the vibratory system continually in motion. This motor magnet and its battery work in a local circuit and cause vibration in exactly the same manner as the armature of an ordinary electric door bell is caused to vibrate. The battery from which the ringing current is derived is indicated at _3_, and the poles of this are connected, respectively, to the vibrating contacts _4_ and _5_. These contacts are merely the moving members of a pole changing switch, and a study of the action will readily show that when these moving parts engage the right-hand contacts, current will flow to the line supposed to be connected to the terminals _6_ and _7_ in one direction, while, when these parts engage the left-hand contacts, current will flow to the line in the reverse direction. The circuit of the condenser shown is controlled by the armature of the relay _8_. The winding of this relay is put directly in the circuit of the main battery _3_, so that whenever current is drawn from this battery to ring a distant bell, this relay will be operated and will bridge the condenser across the circuit of the line. The purpose of the condenser is to make the impulses flowing from the pole changer less abrupt, and the reason for having its bridged circuit normally broken is to prevent a waste of current from the battery _3_, due to the energy which would otherwise be consumed by the condenser if it were left permanently across the line. [Illustration: Fig. 411. Warner Pole Changer] [Illustration: Fig. 412. Pole Changers for Harmonic Ringing] Pole changers for ringing bells of harmonic party lines are required to produce alternating currents of practically constant frequencies. The ideal arrangement is to cause the direct currents from a storage battery to be alternated by means of the pole changers, and then transformed into higher voltages required for ringing purposes, the transformer also serving to smooth the current wave, making it more suitable for ringing purposes. In Fig. 412 such an arrangement, adapted to develop currents for harmonic ringing on party lines, is shown. The regular common battery of the central office is indicated at _1_, _2_ being an auxiliary battery of dry cells, the purpose of which will be presently referred to. At the right of the battery _1_ there is shown the calling plug with its associated party-line ringing keys adapted to impress the several frequencies on the subscribers' lines. The method by which the current from the main storage battery passes through the motor magnets of the several vibrators, and by which the primary currents through the transformers are made to alternate at the respective frequencies of these vibrators, will be obvious from the drawing. It is also clear that the secondary currents developed in these transformers are led to the several ringing keys so as to be available for connection with the subscribers' lines at the will of the operator. The condensers are bridged across the primary windings of the transformers for the purpose of aiding in smoothing out the current waves. The use of the auxiliary battery _2_ and the retardation coil _3_ in the main supply lead is for the purpose of preventing the pulsating currents drawn from the main battery _1_ from making the battery "noisy." These two batteries have like poles connected to the supply lead, and the auxiliary battery furnishes no current to the system except when the electromotive force of the impulse flowing from the main battery is choked down by the impedance coil and the deficiency is then momentarily supplied for each wave by the auxiliary battery. This is the method developed by the Dean Electric Company for preventing the pole-changer system from causing disturbances on lines supplied from the same main battery. [Illustration: Fig. 413. Multi-Cyclic Generator Set] _Ringing Dynamos._ Alternating and pulsating currents for ringing purposes are also largely furnished from alternating-current dynamos similar to those used in commercial power and lighting work, but specially designed to produce ringing currents of proper frequency and voltage. These are usually driven by electric motors deriving their current either from the commercial supply mains or from the central-office battery. In large exchanges harmonic ringers are usually operated by alternating-current generators driven by motors, a separate dynamo being provided to furnish the current of each frequency. Fig. 413 shows a set of four such generators directly connected to a common motor. As no source of commercial power for driving such generators is absolutely uniform, and since the frequency of the ringing current must remain very close to a constant predetermined rate, some means must be employed for holding the generators at a constant speed of revolution, and this is done by means of a governor shown at the right-hand end of the shaft in Fig. 413. The principle of this governor is shown in Fig. 414. A weighted spring acts, by centrifugal force, to make a contact against an adjustable screw, when the speed of the shaft rises a predetermined amount. This spring and its contact are connected to two collector rings _1_ and _2_ on the motor shaft, and connection is made with these by the brushes _3_ and _4_. The closing of the governor contact serves, therefore, merely to short-circuit the resistance _5_, which is normally included in the shunt field of the motor. This governor is based on the principle that weakening the field increases the speed. It acts to insert the resistance in series with the field winding when the speed falls, and this, in turn, results in restoring the speed to normal. [Illustration: Fig. 414. Governor for Harmonic Ringing Generators] =Auxiliary Signaling Currents.= Alternating currents, such as those employed for busy signals to subscribers in automatic systems, those for causing loud tones in receivers which have been left off the hook switch, and those for producing loud tones in calling receivers connected to composite lines, all need to be of much higher frequency than alternating current for ringing bells. The simplest way of producing such tones is by means of an interrupter like that of a vibrating bell; but this is not the most reliable way and it is usual to produce busy or "busy-back" currents by rotating commutators to interrupt a steady current at the required rate. As the usual busy-back signal is a series of recurrent tones about one-half second long, interspersed with periods of silence, the rapidly commuted direct current is required to be further commuted at a slow rate, and this is conveniently done by associating a high-speed commutator with a low-speed one. Such an arrangement may be seen at the left-hand end of the multicyclic alternating machine shown in Fig. 413. This commuting device is usually associated with the ringing machine because that is the one thing about a central office that is available for imparting continuous rotary motion. =Primary Sources.= Most telephone power plants consume commercial electric power and deliver special electric current. Usually some translating device, such as a motor-generator or a mercury-arc rectifier, is employed to transform the commercial current into the specialized current required for the immediate uses of the exchange. _Charging from Direct-Current Mains._ In some cases commercial direct current is used to charge the storage batteries without the intervention of the translating devices, resistances being used in series with the battery to regulate the amount of current. Commercial direct current usually is available at pressures from 110 volts and upward, while telephone power plants contain storage batteries rarely of pressures higher than 50 volts. To charge a 50-volt storage battery direct from 110-volt mains results in the loss of about half the energy purchased, this lost energy being set free in the form of heat generated in the resistance devices. Notwithstanding this, it is sometimes economical to charge directly from the commercial direct-current power mains, but only in small offices where the total amount of current consumed is not large and where the greatest simplicity in equipment is desirable. It is better, however, in nearly all cases, to convert the purchased power from the received voltage to the required voltage by some form of translating device, such as a rotary converter or a mercury-arc rectifier. _Rotary Converters._ Broadly speaking, a rotary converter consists of a motor adapted to the voltage and kind of current received, mechanically coupled to a generator adapted to produce current of the required kind and voltage. The harmonic ringing machine shown in Fig. 413 is an example of this, this particular one being adapted to receive direct current at ordinary commercial pressure and to deliver four different alternating currents of suitable pressures and frequencies. It is to be understood, however, that the conversion may be from direct current to direct current, from alternating to direct, or from direct to alternating. Such a device where the motor is a separate and distinct machine from the generator or generators is called a _motor-generator_. It is usual to connect the motors and the generators together directly by a coupling having some flexibility, as shown in Fig. 413, so as to prevent undue friction in the bearings. [Illustration: THE POWER AND WIRE CHIEF'S ROOM OF THE EXCHANGE AT WEBB CITY, MISSOURI] As an alternative to the converting device made up of a motor coupled to a generator, both motor and generator windings may be combined on the same core and rotate within the same field. Such a rotary converter has been called a _dynamotor_. As a rule the dynamotor is only suitable for small power-plant work. It has the following objectionable features: (_a_) It is difficult to regulate its output, since the same field serves for both the motor and the dynamo windings. For this reason its main use is as a ringing machine where the regulation of the output is not an important factor. (_b_) Furthermore, the fact that the motor and dynamo armature windings are on the same core makes it difficult to guard against breakdowns of the insulation between the two windings, especially when the driving current is of high voltage. _Charging Dynamos._ The dynamo for charging the storage battery is, of course, a direct-current machine and may be a part of a motor generator or it may derive its power from some other than an electric motor, such as a gas or steam engine. It should be able to develop a voltage slightly above that of the voltage of the storage battery when at its maximum charge, so as always to be able to deliver current to the charging battery regardless of the state of charge. A 30-volt generator, for example, can charge eleven cells in series economically; a 60-volt generator can charge twenty-five cells in series economically. Battery-charging generators are controlled as to their output by varying a resistance in series with their fields. Such machines are usually shunt-wound. Sometimes they are compound-wound, but compounding is less important in telephone generators than in some other uses. A feature of great importance in the design of charging generators is smoothness of current. If it were possible to design generators to produce absolutely even or smooth current, the storage battery would not be such an essential feature to common-battery exchanges, because then the generator might deliver its current directly to the bus bars of the office without any storage-battery connection and without causing noise on the lines. Such generators have been built in small units. Even if these smooth current generators were commercially developed to a degree to produce absolutely no noise on the lines, the storage battery would still be used, since its action as a reservoir for electrical energy is important. It not only dispenses with the necessity of running the generators continuously, but it also affords a safeguard against breakdowns which is one of its important uses. The ability to carry the load of a central office directly on the charging generator without the use of a storage battery is of no importance except in an emergency which takes the storage battery wholly out of service. Since the beginning of common-battery working such emergencies have happened a negligible number of times. Far more communities have lacked telephone service because of accidents beyond human control than because of storage-battery failures. In power plants serving large offices, the demand upon the storage battery is great enough to require large plate areas in each cell. The internal resistance, therefore, is small and considerable fluctuations may exist in the charging current without their being heard in the talking circuits. The amount of noise to be heard depends also on the type of charging generator. Increasing the number of armature coils and commutator segments increases the smoothness of the charging current. The shape of the generator pole pieces is also a factor in securing such smoothness. If, with a given machine and storage battery, the talking circuits are disturbed by the charging current, relief may be obtained by inserting a large impedance in the charging circuit. This impedance requires to be of low resistance, because whatever heat is developed in it is lost energy. This means that the best conditions exist when the resistance is low and the inductance large. These conditions are satisfied by using in the impedance coil many turns of large wire and an ample iron core. Dynamotors are not generally suitable for charging purposes. Not only is the difficulty in regulating their output a disadvantage, but the fact that the primary and secondary windings are so closely associated on the armature core makes them carry into the charging current, not only the commutator noises of the generator end, but of the motor end as well. _Mercury-Arc Rectifiers._ In common-battery offices serving a few hundred lines, and where the commercial supply is alternating current, it is good practice to transform it into direct-battery charging current by means of a mercury-arc rectifier. It is a device broadly similar to the mercury-arc lamp produced by Peter Cooper Hewitt. It contains no moving parts and operates at high efficiency without introducing noises into the telephone lines. It requires little care and has good length of life. [Illustration: Fig. 415. Mercury-Arc Rectifier Circuits] The circuit of a mercury-arc rectifier charging outfit is shown in Fig. 415. The mercury-arc rectifier proper consists of a glass bulb containing vacuum and a small amount of mercury. When its terminals are connected, as indicated--the two anodes across an alternating-current source and the cathode with a circuit that is to be supplied with direct current--this device has the peculiarity of action that current will flow alternately from the two anodes always to the cathode and never from it. The cathode, therefore, becomes a source of positive potential and, as such, is used in charging the storage battery through the series reactance coil and the compensating reactances, as indicated. The line transformer shown at the upper portion of Fig. 415, is the one for converting the high-potential alternating current to the comparatively low-potential current required for the action of the rectifier. The transformer below this has a one-to-one ratio, and is called the insulating transformer. Its purpose is to safeguard the telephone apparatus and circuits against abnormal potentials from the line, and also to prevent the ground, which is commonly placed on the neutral wire of transformers on commercial lighting circuits, from interfering with the ground that is commonly placed on the positive pole of the central-office battery. =Provision Against Breakdown.= In order to provide against breakdown of service, a well-designed telephone power plant should have available more than one primary source of power and more than one charging unit and ringing unit. _Duplicate Primary Sources._ In large cities where the commercial power service is highly developed and a breakdown of the generating station is practically impossible, it is customary to depend on that service alone. In order to insure against loss of power due to an accident to portions of the distributing system, it is the common custom to run two entirely separate power leads into the office, coming, if possible, from different parts of the system so that a breakdown on one section will not deprive the telephone exchange of primary power. In smaller places where the commercial service is not so reliable, it is usual to provide, in addition to the commercial electric-power service, an independent source of power in the form of a gas or steam engine. This may be run as a regular source, the commercial service being employed as an emergency or _vice versâ_, as economy may dictate. In providing a gas engine for driving charging dynamos, it is important to obtain one having as good regulation as possible, in order to obtain a charging current of practically constant voltage. _Duplicate Charging Machines._ The storage batteries of telephone exchanges are usually provided of sufficient capacity to supply the direct-current needs of the office for twenty-four hours after a full charge has been given them. This in itself is a strong safeguard against breakdown. In addition to this the charging machines should be in duplicate, so that a burnt-out armature or other damage to one of the charging units will not disable the plant. _Duplicate Ringing Machines._ It is equally important that the ringing machines, whether of the rotary or vibrating type, be in duplicate. For large exchanges the ringing machines are usually dynamos, and it is not unusual to have one of these driven from the commercial power mains and the other from the storage battery. With this arrangement complete failure of all sources of primary power would still leave the exchange operative as long as sufficient charge remains in the storage battery. _Capacity of Power Units._ In designing telephone switchboards it is the common practice to so design the frameworks that the space for multiple jacks is in excess of that required for the original installation. In a like manner, the power plant is also designed with a view of being readily increased in capacity to an amount sufficient to provide current for the ultimate number of subscribers' lines for which the switchboard is designed. The motor generators, or whatever means are provided for charging the storage batteries, are usually installed of sufficient size to care for the ultimate requirements of the office. The ringing machines are also provided for the ultimate equipment. However, in the case of the storage battery, it is common practice to provide the battery tanks of sufficient size to care for the ultimate capacity, while the plates are installed for a capacity only slightly in excess of that required for the original installation. As the equipment of subscribers' lines is increased, additional plates may, therefore, be added to the cells without replacing the storage battery as a whole, and without making extraordinary provisions to prevent the interruption of service. It is also customary to provide charging and supply leads from the storage battery of carrying capacity sufficient for the ultimate requirements of the office. =Storage Battery.= The storage battery is the power plant element which has made common-battery systems possible. The common-battery system is the element which has made the present wide development of telephony possible. A storage-battery cell is an electro-chemical device in which a chemical state is changed by the passage of current through the cell, this state tending to revert when a current is allowed to flow in the opposite direction. A storage cell consists of two conductors in a solution, the nature and the relation of these three elements being such that when a direct current is made to pass from one conductor to the other through the solution, the compelled chemical change is proportional to the product of the current and its duration. When the two conductors are joined by a path over which current may flow, a current does flow in the opposite direction to that which charged the cell. All storage batteries so far in extensive use in telephone systems are composed of lead plates in a solution of sulphuric acid in water called the _electrolyte_. In charging, the current tends to oxidize the lead of one plate and de-oxidize the other. In discharging, the tendency is toward equilibrium. The containers, employed in telephone work, for the plates and electrolyte are either of glass or wood with a lead lining, the glass jars being used for the smaller sized plates of small capacity cells, while the lead-lined wooden tanks are employed with the larger capacity cells. The potential of a cell is slightly over two volts and is independent of the shape or size of the plates for a given type of battery. The storage capacity of a cell is determined by the size and the number of plates. Therefore, by increasing the number of plates and the areas of their surfaces, the ampere-hour capacity of the cell is correspondingly increased. The desired potential of the battery is obtained by connecting the proper number of cells in series. Storage-battery cells used in telephone work vary from 2 plates having an area of 12 square inches each, to cells having over 50 plates, each plate having an area of 240 square inches. The ampere-hour capacity of these batteries varies from 6 ampere hours to 4,000 ampere hours, respectively, when used at an average 8-hour discharge rate. In Fig. 416 is illustrated a storage cell employing a glass container and having fifteen plates. Each plate is 11 inches high and 10-1/2 inches wide, with an area, therefore, of 115.5 square inches. Such a cell has a normal capacity of 560 ampere hours. The type illustrated is one made by the Electric Storage Battery Company of Philadelphia, Pa.[A] [Illustration: Fig. 416. Storage Cell] _Installation._ In installing the glass jars it is customary to place them in trays partially filled with sand. They are, however, at times installed on insulators so designed as to prevent moisture from causing leakage between the cells. The cells using wooden tanks are placed on glass or porcelain insulators, and the tanks are placed with enough clearance between them to prevent the lead lining of adjacent tanks from being in contact and thereby short-circuiting the cells. After the positive and the negative plates have been installed in the tanks, their respective terminals are connected to bus bars, these bus bars being, for the small types of battery, lead-covered clamping bolts, while in the larger types reinforced lead bus bars are employed, to which the plates are securely joined by a process called lead burning. This process consists in melting a portion of the bus bar and the terminal lug of the plate by a flame of very high temperature, thus fusing each individual plate to the proper bus bar. The plates of adjacent cells are connected to the same bus bar, thus eliminating the necessity of any other connection between the cells. _Initial Charge._ As soon as the plates have been installed in the tanks and welded to the bus bars, the cell should be filled with electrolyte having a specific gravity of 1.180 to 1.190 to one-half inch above the tops of the plates and then the charge should be immediately started at about the normal rate. In the case of a battery consisting of cells of large capacity, it is customary to place the electrolyte in the cells as nearly simultaneously as possible rather than to completely fill the cells in consecutive order. When the electrolyte is placed in the cells simultaneously, the charge is started at a very much reduced rate before the cells are completely filled, the rate being increased as the cells are filled, the normal rate of charge being reached when the cells are completely filled. Readings should be taken hourly of the specific gravity and temperature of the electrolyte, voltage of the cells, and amperage of charging current. A record or log should be kept of the specific gravity and voltage of each of the cells of the battery regularly during the life of the battery and it is well to commence this record with the initial charge. The initial charge should be maintained for at least ten hours after the time when the voltage and specific gravity have reached a maximum. If for any reason it is impractical to continue the initial charge uninterrupted, the first period of charging should be at least from twelve to fifteen hours. However, every effort should be made to have the initial charge continuous, as an interruption tends to increase the time necessary for the initial charge, and if the time be too long between the periods of the initial charge, the efficiency and capacity of the cells are liable to be affected. In case of a large battery, precaution should be taken to insure that the ventilation is exceptionally good, because if it is not good the temperature is liable to increase considerably and thereby cause an undue amount of evaporation from the cells. The object of the temperature readings taken during the charge is to enable corrections to be made to the specific gravity readings as obtained by the hydrometer, in order that the correct specific gravity may be ascertained. This correction is made by adding .001 specific gravity for each three degrees in temperature above 70° Fahrenheit, or subtracting the same amount for each three degrees below 70° Fahrenheit. At the time the cells begin to gas they should be gone over carefully to see that they gas evenly, and also to detect and remedy early in the charging period any defects which may exist. If there is any doubt in regard to the time at which the cells reach a maximum voltage and specific gravity, the charge should be continued sufficiently long before the last ten hours of the charge are commenced to eliminate any such doubt, as in many cases poor efficiency and low capacity of a cell later in its life may be traced to an insufficient initial charge. _Operation._ After the battery has been put in commission the periodic charges should be carefully watched, as excessive charging causes disintegration and decreases the life and capacity of the battery; while, on the other hand, undercharging will result in sulphating of the plates and decrease of capacity, and, if the undercharge be great, will result in a disintegration of the plates. It is, therefore, essential that the battery be charged regularly and at the rate specified for the particular battery in question. In order to minimize the chance of either continuously overcharging or undercharging the battery, the charges are divided into two classes, namely, regular charges and overcharges. The regular charges are the periodic charges for the purpose of restoring the capacity of the battery after discharge. The overcharges, which should occur once a week or once in every two weeks, according to the use of the battery, are for the purpose of insuring that all cells have received their proper charge, for reducing such sulphating as may have occurred on cells undercharged, and for keeping the plates, in general, in a healthy condition. The specific gravity of the electrolyte, the voltage of the battery, and the amount of gasing observed are all indications of the amount of charge which the battery has received and should all be considered when practicable. Either the specific gravity or voltage may be used as the routine method of determining the proper charge, but, however, if the proper charge is determined by the voltage readings, this should be frequently checked by the specific gravity, and _vice versâ_. During the charging and discharging of a battery the level of the electrolyte in the cells will fall. As the portion of the electrolyte which is evaporated is mainly water, the electrolyte may be readily restored to its normal level by adding distilled water or carefully collected rain water. _Pilot Cell._ As the specific gravity of all the cells of a battery, after having once been properly adjusted, will vary the same in all the cells during use, it has been found satisfactory to use one cell, commonly termed the pilot cell, for taking the regular specific gravity readings and only reading the specific gravity of all the cells occasionally or on the overcharge. This cell must be representative of all the cells of the battery, and if the battery is so subdivided in use that several sets of cells are liable to receive different usage, a pilot cell should be selected for each group. _Overcharge._ If the battery is charged daily, it should receive an overcharge once a week, or if charged less frequently, an overcharge should be given at least once every two weeks. In making an overcharge this should be done at a constant rate and at a rate specified for the battery. During the overcharge the voltage of the battery and the specific gravity of the pilot cell should be taken every fifteen minutes from the time the gasing begins. The charge should be continued until five consecutive, specific-gravity readings are practically the same. The voltage of the battery should not increase during the last hour of the charge. As the principal object of the overcharge is to insure that all of the cells have received the proper charge, it must, therefore, be continued long enough to not only properly charge the most efficient cells, but also to properly charge those which are lower in efficiency. The longer the interval between overcharges, the greater will be the variation between the cells and, therefore, it is necessary to continue the overcharge longer when the interval between overcharges is as great as two weeks. Before the overcharge is made the cells should be carefully inspected for short circuits and other abnormal conditions. These inspections may best be made by submerging an electric lamp in the cell, if the cell be of wood, or of allowing it to shine through from the outside, if it be of glass. By this means any foreign material may be readily detected and removed before serious damage is caused. In making these inspections it must be borne in mind that whatever tools or implements are used must be non-metallic and of some insulating material. _Regular Charge._ Regular charges are the periodic charges for restoring the capacity of the battery, and should be made as frequently as the use of the battery demands. The voltage of the cells is a good guide for determining when the battery should be recharged. The voltage of a cell should never be allowed to drop below 1.8 volts, and it is usually considered better practice to recharge when the battery has reached 1.9 volts. If a battery is to remain idle for even a short time, it should be left in a completely charged condition. The regular charges for cells completely equipped with plates should be continued until the specific gravity of the pilot cell has risen to five points below the maximum attained on the preceding overcharge, or, if only partially equipped with plates, until it has risen to three points below the previous maximum. The voltage per cell at this time should be from .05 volts to .1 volts below that obtained on the previous overcharge. At this time all the cells should be gasing, but not as freely as on an overcharge. _Low Cells._ An unhealthy condition in a cell usually manifests itself in one of the following ways: Falling off in specific gravity or voltage relative to the rest of the cells, lack of gasing when charged, and color of the plates, either noticeably lighter or darker than those of other cells of the battery. When any of the above conditions are found in a cell, the cell should receive immediate attention, as a delay may mean serious trouble. The cell should be thoroughly inspected to determine if a short-circuit exists, either caused by some foreign substance, by an excess of sediment in the bottom of the tank, or by portions of the plates themselves. If such a condition is found, the cause should be immediately removed and, if the defect has been of short duration, the next overcharge will probably restore it to normal condition. If the defect has existed for some time, it is often necessary to give the cell a separate charge. This may be done by connecting it directly to the charging generator with temporary leads and thus bring it back to its normal condition. It is sometimes found necessary to replace the cell in order to restore the battery to its normal condition. _Sediment._ The cells of the battery should be carefully watched to prevent the sediment which collects in the bottom of the jar or tank during use from reaching the bottom of the plates, thereby causing short circuits between them. When the sediment in the cell has reached within one-half inch of the bottom of the plates, it should be removed at once. With small cells using glass jars this can most easily be done directly after an overcharge by carefully drawing off the electrolyte without disturbing the sediment and then removing it from the jar. The plates and electrolyte should be replaced in the jar as soon as convenient to prevent the plates from becoming dry. If the plates are large and in wooden tanks, the sediment can most easily be removed by means of a scoop made especially for the purpose. The preferable time to clean the tanks is just before an overcharge. _Replacing Batteries._ There comes a time in the life of nearly every central-office equipment when the storage battery must be completely renewed. This is due to the fact that the life of even the best of storage batteries is not as great as the life of the average switchboard equipment. It may also be due to the necessity for greater capacity than can be secured with the existing battery tanks, usually caused by underestimating the traffic the office will be required to handle. Again, it is sometimes necessary to make extensive alterations in an existing battery, perhaps due to the necessity for changing its location. To change a battery one cell at a time, keeping the others in commission meanwhile, has often been done, but it is always expensive and unsatisfactory and is likely to shorten the life of the battery, due to improper and irregular forming of the plates during the initial charge. The advent of the electric automobile industry has brought with it a convenient means for overcoming this difficulty. Portable storage cells for automobile use are available in almost every locality and may often be rented at small cost. A sufficient number of such cells may be temporarily installed, enough of them being placed in multiple to give the necessary output. By floating a temporary battery so formed across the charging mains and running the generators continuously, a temporary source of current supply may be had at small expense for running the exchange during the period required for alterations. Usually a time of low traffic is chosen for making the changes, such as from Saturday evening to Monday morning. Very large central-office batteries, serving as many as 6,000 lines, have thus been taken out of service and replaced without interfering with the traffic and with the use of but a comparatively few portable cells. One precaution has to be observed in such work, and that is not to subject the portable cells to too great an overcharge, due to the great excess of generator over battery capacity. This is easily avoided by watching the ammeters to see that the input is not in too great excess of the output, and if necessary, by frequently stopping the machines to avoid this. =Power Switchboard.= The clearing-house of the telephone power plant is the power board. In most cases, it carries switches, meters, and protective devices. _Switches._ The switches most essential are those for opening and closing the motor and the generator circuits of the charging sets and with these usually are associated the starting rheostats of the motors and the field rheostats of the generators. The starting rheostats are adapted to allow resistance to be removed from the motor armature circuit, allowing the armature to gain speed and increase its counter-electromotive force without overheating. The accepted type has means for opening the driving circuit automatically in case its voltage should fall, thus preventing a temporary interruption of driving current from damaging the motor armature on its return to normal voltage. [Illustration: Fig. 417. Power-Plant Circuits] _Meters._ The meters usually are voltmeters and ammeters, the former being adapted to read the several voltages of direct currents in the power plant. An important one to be known is the voltage of the generator before beginning a battery charge, so that the generator may not be thrown on the storage battery while generating a voltage less than that of the battery. If this were done, the battery would discharge through the generator armature. The voltmeter enables the voltage of the charging generator to be kept above that of the battery, as the latter rises during charge. It enables the performance of several cells of the battery to be observed. A convenient way is to connect the terminals of the several cells to jacks on the power board and to terminate the voltmeter in a plug. The ammeter, with suitable connections, enables the battery-charge rate to be kept normal and the battery discharge to be observed. In order to economize power, it is best to charge the battery during the hours of heavy load. The generator output then divides, the switchboard taking what the load requires, the battery receiving the remainder. In systems requiring the terminal voltage of the equipment to be kept constant within close limits, either it is necessary to use two batteries--never drawing current from a battery during charge--or to provide means of compensating for the rise of voltage while the battery is under charge. The latter is the more modern method and is done either by using fewer cells when the voltage per cell is higher or by inserting counter-electromotive force cells in the discharge leads, opposing the discharge by more or fewer cells as the voltage of the battery is higher or lower. In either method, switches on the power board enable the insertion and removal of the necessary end cells or counter-electromotive force cells. _Protective Devices._ The protective devices required on a power board are principally _circuit-breakers_ and _fuses_. Circuit-breakers are adapted to open motor and generator circuits when their currents are too great, too small, or in the wrong direction. Fuses are adapted to open circuits when the currents in them are too great. The best type is that in which the operation of the fuses sounds or shows an alarm, or both. =Power-Plant Circuits.= The circuit arrangement of central-office power plants is subject to wide variation according to conditions. The type of telephone switchboard equipment, whether magneto or common-battery, automatic or manual, will, of course, largely affect the circuit arrangement of the power plant. Fig. 417 shows a typical example of good practice in this respect for use with a common-battery manual switchboard equipment. Besides showing the switches for handling the various machines and the charge-and-discharge leads from the storage battery, this diagram shows how current from the storage battery is delivered to various parts of the central-office equipment. [Footnote A: The instructions given later in this chapter are for batteries of this make, although they are applicable in many respects to all types commonly used in telephone work.] CHAPTER XXXIII HOUSING CENTRAL-OFFICE EQUIPMENT =The Central-Office Building.= Proper arrangement of the central-office equipment depends largely upon the design of the central-office building. The problem involved should not be solved by the architect alone. The most careful co-operation between the engineer and the architect is necessary in order that the various parts of the telephonic equipment may be properly related, and that the wires connecting them with each other and with the outside lines be disposed of with due regard to safety, economy, and convenience. So many factors enter into the design of a central-office building that it is impossible to lay down more than the most general rules. The attainment of an ideal is often impossible, because of the fact that the building is usually in congested districts, and its very shape and size must be governed by the lot on which it is built, and by the immediate surroundings. Frequently, also, the building must be used for other purposes than those of a telephone office, so that the several purposes must be considered in its design. Again, old buildings, designed for other purposes, must sometimes be altered to meet the requirements of a telephone office, and this is perhaps the most difficult problem of all. The exterior of the building is a matter that may be largely decided by the architect and owner after the general character of the building has been determined. One important feature, however, and one that has been overlooked in many cases that we know of, is to so arrange the building that switchboard sections and other bulky portions of the apparatus, which are necessarily assembled at the factory rather than on the site, may be brought into the building without tearing down the walls. _Fire Hazard._ The apparatus to be housed in a central-office building often represents a cost running into the hundreds of thousands of dollars; but whether of large or small first cost, it is evident that its destruction might incur a very much greater loss than that represented by its replacement value. In guarding the central-office equipment against destruction by fire or other causes, the telephone company is concerned to a very much greater extent than the mere cost of the physical property; since it is guarding the thing which makes it possible to do business. While the cost of the central office and its contents may be small in comparison with the total investment in outside plant and other portions of the equipment, it is yet true that these larger portions of the investment become useless with the loss of the central office. There is another consideration, and that is the moral obligation of the operating company to the public. A complete breakdown of telephone service for any considerable period of time in a large city is in the nature of a public calamity. For these reasons the safeguarding of the central office against damage by fire and water should be in all cases a feature of fundamental importance, and should influence not only the character of the building itself, but in many cases the choice of its location. _Size of Building._ It goes without saying that the building must be large enough to accommodate the switchboards and other apparatus that is required to be installed. The requirement does not end here, however. Telephone exchange systems have, with few exceptions, grown very much faster than was expected when they were originally installed. Many buildings have had to be abandoned because outgrown. In planning the building, therefore, the engineer should always have in mind its ultimate requirements. It is not always necessary that the building shall be made large enough at the outset to take care of the ultimate requirements, but where this is not done, the way should be left clear for adding to it when necessity demands. [Illustration: RINGING AND CHARGING MACHINES AND POWER BOARD Plaza Office, New York Telephone Co.] _Strength of Building._ The major portion of telephone central-office apparatus, whether automatic or manual, is not of such weight as to demand excessive strength in the floors and walls of buildings. Exceptions to this may be found in the storage battery, in the power machinery, especially where subject to vibration, and in certain cases in the cable runs. After the ultimate size of the equipment has been determined, the engineer and the architect should confer on this point, particularly with reference to the heavier portions of the apparatus, to make sure that adequate strength is provided. The approximate weights of all parts of central-office equipments may readily be ascertained from the manufacturers. _Provision for Employes._ In manual offices particularly it has been found to be not only humane, but economical to provide adequate quarters for the employes, both in the operating rooms and places where they actually perform their work, and in the places where they may assemble for recreation and rest. The work of the telephone operator, particularly in large cities, is of such a nature as often to demand frequent periods of rest. This is true not only on account of the nervous strain on the operator, but also on account of the necessity, brought about by the demands of economy, for varying the number of operators in accordance with the traffic load. These features accentuate the demand for proper rooms where recreation, rest, and nourishment may be had. _Provision for Cable Runways._ In very small offices no special structural provision need be made in the design of the building itself for the entrance of the outside cables, and for the disposal of the cables and wires leading between various portions of the apparatus. For large offices, however, this must necessarily enter as an important feature in the structure of the building itself. It is important that the cables be arranged systematically and in such a way that they will be protected against injury and at the same time be accessible either for repairs or replacement, or for the addition of new cables to provide for growth. Disorderly arrangement of the wires or cables results in disorder indeed, with increased maintenance cost, uneconomical use of space, inaccessibility, liability to injury, and general unsightliness. The carrying of cables from the basement to the upper floors or between floors elsewhere must be provided for in a way that will not be wasteful of space, and arrangements must be made for supporting the cables in their vertical runs. In the aggregate their weight may be great, and furthermore each individual cable must be so supported that its sheath will not be subject to undue strain. Another factor which must be considered in vertical cable runs is the guarding against such runs forming natural flues through which flames or heated gases would pass, in the event of even an unimportant fire at their lower ends. =Arrangement of Apparatus in Small Manual Offices.= Where a common-battery multiple switchboard equipment is used, at least three principal rooms should be provided--one for the multiple switchboard proper; one for the terminal and power apparatus, including the distributing frames, racks, and power machinery; and the third for the storage battery. These should adjoin each other for purposes of convenience and of economy in wiring. [Illustration: Fig. 418. Typical Small Office Floor Plan] _Floor Plans for Small Manual Offices._ As was pointed out, there are several plans of disposing of the main and intermediate distributing frames and the line and cut-off relay racks. The one most practiced is to mount the relay rack alongside the main and intermediate distributing frame in the terminal room. A typical floor plan of such an arrangement for a small office, employing as a maximum five sections of multiple switchboards, is shown in Fig. 418. This is an ideal arrangement well adapted for a rectangular floor space and on that account may often be put into effect. It should be noted that the switchboard grows from left to right, and that alternative arrangements are shown for disposing of those sections beyond the second. The cable turning section through which the multiple and answering jacks are led to the terminal frames is placed as close as possible to the terminal frames. This results in a considerable saving in cable. An interesting feature of this floor plan is the arrangement of unitary sections of main and intermediate frames and relay racks, representing recent practice of the Western Electric Company. The iron work of the three racks is built in sections and these are structurally connected across so that the first section of the main frame, the intermediate frame, and the relay rack form one unit, the structural iron work which ties them together forming the runway for the cables between them. But two of these units, including two sections of each frame, are shown installed, the provision for growth being indicated by dotted lines. The battery room in this case provides for the disposal of the battery cells in two tiers. This room is merely partitioned off from the distributing or terminal room. Where this is done the partition walls should be plastered on both sides so as to prevent, as far as possible, the entrance of any battery fumes into the apparatus rooms. The wire chief's desk, as will be noted, is located in such a position as to give easy access from it not only to the distributing frames and relay rack, but to the power apparatus as well. _Combined Main and Intermediate Frames._ For use in small exchanges, the Western Electric Company has recently put on the market a combined main and intermediate distributing frame. This is constructed about the same as an ordinary main frame, the protectors being on one side and the line and intermediate frame terminals on the other. The lower half of the terminals on each vertical bay is devoted to the outside line terminals and the upper half is devoted to intermediate frame terminals. This arrangement is indicated in the elevation in Fig. 419. With the use of this combined main and intermediate frame, the floor plan of Fig. 418 may be modified, as shown in Fig. 420. [Illustration: Fig. 419. Combined Main and Intermediate Frames] [Illustration: Fig. 420. Small Office Floor Plan] [Illustration: Fig. 421. Terminal Apparatus--Small Office] In Fig. 421 is given an excellent idea of terminal-room apparatus carried out in accordance with the more usual plan of employing separate main and intermediate distributing frames. At the extreme right of this figure the protector side of the main frame is shown. It will be understood that the line cables terminate on the horizontal terminal strips on the other side of this frame and are connected through the horizontal and vertical runways of the frame to the protector terminals. The intermediate frame is shown in the central portion of the figure, the side toward the left containing the answering-jack terminals, and the side toward the right the multiple jack terminals, these latter being arranged horizontally. This horizontal and vertical arrangement of the terminals on the main and intermediate distributing frames has been the distinguishing feature between the Bell and Independent practice, the Bell Companies adhering to the horizontal and vertical arrangement, while the Independent Companies have employed the vertical arrangement on both sides. We are informed that in the future the new smaller installations of the Bell Companies will be made largely with the vertical arrangement on both sides. At the left of Fig. 421 is shown the relay rack in two sections of two bays each. This illustration also gives a good idea of the common practice in disposing of the cables between the frames in iron runways just below the ceiling of the terminal room. _Types of Line Circuits._ The design of the terminal-room floor plan will depend largely on the arrangement of apparatus in the subscribers' line circuits with respect to the distributing frames and relay racks. The Bell practice in this respect has already been referred to and is illustrated in Fig. 348. In this the line and cut-off relays are permanently associated with the answering jacks and lamps, resulting in the answering-jack equipment being subject to change with respect to the multiple and the line through the jumpers of the intermediate frame. The practice of the Kellogg Company, on the other hand, has been illustrated in Fig. 353, and in this the line and cut-off relays are permanently associated with the multiple and with the line, only the answering jacks and lamps being subject to change through the jumper wires on the intermediate frame. This latter arrangement has led to a very desirable parallel arrangement of the two distributing frames and the relay rack. These are made of equal length so as to correspond bay for bay, and are placed side by side with only enough space between them for the passage of workmen--the relay rack lying between the main and intermediate frames. In this scheme all the multiple and answering-jack cables run from the intermediate distributing frame, and the cabling between the intermediate frame and the relay rack and between the relay rack and the main frame is run straight across from one rack to the other. This results in a great saving of cable within the terminal room, over that arrangement wherein the cabling from one frame to another is necessarily led along the length of the frame to its end and then passes through a single runway to the end of the other frame. =Large Manual Offices.= For purposes of illustrating the practice in housing the apparatus in very large offices equipped with manual switchboards, we have chosen the Chelsea office of the New York Telephone Company as an excellent example of modern practice. [Illustration: Fig. 422. Floor Plan, Operating Room, Chelsea Office, New York City] The ground plan of the building is U-shaped, in order to provide the necessary light over the rather large floor areas. The plan of the operating floor--the sixth floor of the building--is shown in Fig. 422. As will be seen, this constitutes a single operating room, the _A_-board being located in the right wing and the _B_-board in the left. The point from which both boards grow is near the center of the front of the building, the boards coming together at this point in a common cable turning section. The disposal of the various desks for the manager, chief operator, and monitors is indicated. Those switchboard sections which are shown in full lines are the ones at present installed, the provision for growth being indicated in dotted lines. [Illustration: Fig. 423. Terminal Room and Operators' Quarters, Chelsea Office, New York City] The fifth floor is devoted to the terminal room and operators' quarters, the terminal room occupying the left-hand wing and the major portion of the front of the building, and the operators' quarters the right-hand wing. The line and the trunk cables come up from the basement of the building at the extreme left, being supported directly on the outside wall of the building. Arriving at the fifth floor, they turn horizontally and are led under a false flooring provided with trap doors, to the protector side of the main frame. The disposal of the cables between the various frames will be more readily understood by reference to the following photographs. A general view of a portion of the _A_-board of the Chelsea office is shown in Fig. 424, this view being taken from a point in the left-hand wing looking toward the front. In Fig. 425 is shown a closer view of a smaller portion of the board. Fig. 426 gives an excellent idea of the rear of this switchboard and of the disposal of the cables and wires. The main mass of cables at the top are those of the multiple. Immediately below these may be seen the outgoing trunk cables. The forms of the answering-jack cables lie below these and are not so readily seen, but the cables leading from these forms are led down to the runway at the bottom of the sections, and thence along the length of the board to the intermediate distributing frame on the floor below. The layer of cables, supported on the iron rack immediately above the answering-jack cable runway, shown at the extreme bottom of the view, are those containing the wires leading from the repeating coils to the cord circuits. An interesting feature of this board is the provisions for protection against injury by fire and water. On top of the boards throughout their entire length there is laid a heavy tarpaulin curtain with straps terminating in handles hanging down from its edges. These may be seen in Fig. 426 and also in Fig. 425. The idea of this is that if the board is exposed to a water hazard, as in the case of fire, the board may be completely covered, front and rear, with this tarpaulin curtain, by merely pulling the straps. The entire force--both operators and repairmen--is drilled to assure the carrying out of this plan. The rear of the boards is adapted to be enclosed by wooden curtains, similar to those employed in roll-top desks. These are all raised in the rear view of Fig. 426, the housing for the rolled-up curtain being shown at the extreme top of the sections. In order to guard the multiple cables and the multiple jacks against fire which might originate in the cord-circuit wiring, a heavy asbestos partition is placed immediately above the cord racks and is clearly shown in Fig. 426. [Illustration: Fig. 424. Subscribers' Board. Chelsea Office, New York City] [Illustration: Fig. 425. Subscribers' Board. Chelsea Office, New York City] [Illustration: Fig. 426. Rear View Chelsea Switchboard] [Illustration: Fig. 427. Terminal and Power Apparatus. Chelsea Office] A view of the terminal and power room is shown in Fig. 427. In the upper left-hand corner the cables may be seen in their passage downward from the cable turning section between the _A_- and _B_-boards. The large group of cables shown at the extreme left is the _A_-board multiple. This passes down and then along the horizontal shelves of the intermediate frame, which is the frame in the extreme left of this view. The _B_-board multiple comes down through another opening in the floor, and as is shown, after passing under the _A_-board multiple joins it in the same vertical run from which it passes to the intermediate frame. The cord-circuit cables lead down through the same opening as that occupied by the _A_-board multiple and pass off to the right-hand one of the racks shown, which contains the repeating coils. The cables leading from the opening in the ceiling to the right-hand side of the intermediate distributing frame are the answering-jack cables, and from the terminals on this side of this frame other cables pass in smaller groups to the relay terminals on the relay racks which lie between the intermediate frame and the coil rack. The power board is shown at the extreme right. The fuse panel at the left of the power board contains in its lower portion fuses for the battery supply leads to the operator's position and to private-branch exchanges, and in its upper portion lamps and fuses for the ringing generator circuits for the various operators' positions and also for private-branch exchanges. At the lower left-hand portion of this view is shown the battery cabinet. It is the practice of the New York Telephone Company not to employ separate battery rooms, but to locate its storage batteries directly in the terminal room and to enclose them, as shown, in a wooden cabinet with glass panels, which is ventilated by means of a lead pipe extending to a flue in the wall. One unit of charging machines, consisting of motor and generator, is shown in the immediate foreground. A duplicate of this unit is employed but is not shown in this view. The various ringing and message register machines are shown beyond the charging machines. Three of these smaller machines are for supplying ringing current and the remainder are for supplying 30-volt direct current for operating the message registers. One of the machines of each set is wound to run from the main storage battery in case of a failure of the general lighting service from which the current for operating is normally drawn. [Illustration: Fig. 428. Terminal Apparatus. Chelsea Office] [Illustration: Fig. 429. Floor Plan, Automatic Office, Lansing, Michigan] Another view of the terminal-room apparatus is given in Fig. 428. This is taken from the point marked _B_ on the floor plan of Fig. 423. At the right may be seen the message registers on which the calls of the subscribers in this office are counted as a basis for the bills for their service. At the extreme left is shown the private-line test board. Through this board run all of the lines leased for private use, and also all of the order wire or call lines passing through this office. The purpose of such an arrangement is to facilitate the testing of such line wires. At the right of this private-line test board is shown a four-position wire chief's desk, upon which are provided facilities for making all of the tests inside and outside. [Illustration: Fig. 430. Line-Switch Units] [Illustration: Fig. 431. Automatic Apparatus at Lansing Office] The main frame is shown at the right of Fig. 428, just to the right of a gallery from which a step-ladder leads. The left-hand side of this frame is the line or protector side, but the portion toward the observer in this picture is unequipped. These equipped protector strips carry 400 pairs of terminals each, and the consequent length of these strips makes necessary the gallery shown, in order that all of them may be readily accessible. [Illustration: Fig. 432. Main Distributing Frame, Lansing Office] [Illustration: Fig. 433. Line Switches] [Illustration: POWER PLANT FOR AUTOMATIC SWITCHBOARD EQUIPMENT Bay Cities Home Telephone Company, Berkeley, Cal.] [Illustration: Fig. 434. Secondary Line Switches and First Selectors] =Automatic Offices.= There is no great difference in the amount of floor space required in central offices employing automatic and manual equipment. Whatever difference there is, is likely to be in favor of the automatic. The fact that no such rigid requirement exists in the arrangement of automatic apparatus, as that which makes it necessary to place the sections of a multiple board all in one row, makes it possible to utilize the available space more economically with automatic than with manual equipment. [Illustration: Fig. 435. Second Selectors] [Illustration: Fig. 436. Toll Distributing Frame and Harmonic Converters] In manual practice it is necessary to place the distributing frames and power apparatus in a separate room from that containing the switchboard, but in an automatic exchange no such necessity exists; in fact, so far as the distributing-frame equipment is concerned, it is considered desirable to have it located in the same room as the automatic switches. The battery room in an automatic exchange should be entirely separate from the operating room, since the fumes from the battery would be fatal to the proper working of the automatic switches. _Typical Automatic Office._ The floor-plan and views of a medium-sized automatic office at Lansing, Michigan, have been chosen as representing typical practice. The floor plan is shown in Fig. 429. The apparatus indicated in full lines represents the present equipment, and that in dotted lines the space that will be required by the expected future equipment. In Fig. 430 is shown a group of five line-switch units, representing a total of five hundred lines. The length of such a unit is practically fourteen feet and the breadth over all about twenty-two inches. Fig. 431 shows a general view of this Lansing office, taken from a point of view indicated at _A_ on the floor plan of Fig. 429. Fig. 432 shows the main distributing frame, which is of ordinary type; Fig. 433 shows a closer view of some of the primary line switches; Fig. 434 is a view of the secondary line switches and first selectors, the latter being on the right; Fig. 435 is a view of the frequency selectors and second selectors, the former being used in connection with party-line work; and Fig. 436 is a view of the toll distributing frame and harmonic converters for party-line ringing. A general view of the main switching room in the Grant Avenue office of the Home Telephone Company of San Francisco is given in Fig. 437, this being taken before the work of installation had been fully completed. The present capacity of the equipment is 6,000 and the ultimate 12,000 lines. This office is one of a number of similar ones recently installed for the Home Telephone Company in San Francisco, the combination of which forms by far the largest automatic exchange yet installed. The scope of the plans is such as to enable 125,000 subscribers to be served without any change in the fundamental design, and by means merely of addition in equipment and lines as demanded by the future subscriptions for telephone service. [Illustration: Fig. 437. Grant Avenue Office--San Francisco] CHAPTER XXXIV PRIVATE BRANCH EXCHANGES =Definitions.= A telephone exchange devoted to the purely local uses of a private establishment such as a store, factory, or business office, is a private exchange. If, in addition to being used for such local communication, it serves also for communication with the subscribers of a city exchange, it becomes in effect a branch of the city exchange and, therefore, a private branch exchange. The term "P. B. X." has become a part of the telephone man's vocabulary as an abbreviation for private branch exchange. Private exchanges for purely local use require no separate treatment as any of the types of switching equipments for interconnecting the lines for communication, that have been or that will be described herein, may be used. The problem becomes a special one, however, when communication must also be had with the subscribers of a public exchange, since then trunking is involved in which the conditions differ materially from those encountered in trunking between the several offices in a multi-office exchange. For such communication one or more trunk lines are led from the private branch office usually to the nearest central office of the public exchange and such trunks are called private branch-exchange trunks. They are the paths for communication between the private exchange and the public exchange. For establishing the connections either between the local lines themselves or between the local lines and the trunks, and for performing other duties that will be referred to, one or more private branch-exchange operators are employed at the switchboard of the private establishment. The private branch exchange may operate in conjunction with a manual or an automatic public exchange, but whether manual or automatic, the private exchange is usually manually operated, although it is quite possible to make a private branch exchange that is wholly automatic and will, therefore, involve no operator at all. =Functions of the Private Branch-Exchange Operator.= It is possible, as just stated, entirely to dispense with the private branch-exchange operator so far as the mere connection and disconnection of the lines is concerned. But the real function of the private branch-exchange operator is a broader one than this and it is for this reason that even in connection with automatic public exchanges, operators are desirable at the private branches. The private branch-exchange operator is, as it were, the doorkeeper of the telephone entrance to the private establishment. She is the person first met by the public in entering this telephone door. There is the same reason, therefore, why she should be intelligent, courteous, and obliging as that the ordinary doorkeeper should possess these characteristics. As to incoming traffic to a private branch exchange, an intelligent operator may do much toward directing the calls to the proper department or person, even though the person calling may have little idea as to whom he desires to reach. This saves the time of the person who makes the call as well as that of the people at the private branch stations, since it prevents their being unnecessarily called. The functions of the private branch-exchange operator are no less important with respect to outgoing calls. It is the duty of the operator to obtain connections through the city exchange for the private branch subscriber, who merely asks for a certain connection and hangs up his receiver to await her call when she shall have obtained it. This saving of time of busy people by having the branch-exchange operator make their calls for them has one attending disadvantage, which is that the person in the city exchange who is called does not, when he answers his telephone, find the real party with whom he is to converse, but has to wait until that party responds to the private branch operator's call. This is akin to asking a person to call at one's office and then being out when he gets there. This drawback is greatly accentuated where both the parties that are to be involved in the connection are people high in authority in certain establishments at private branch exchanges. Some business houses have made the rule that the private branch operator shall not connect with their lines until she has actually heard the voice of the proper party at the other end. When two subscribers in two different private branch exchanges where this rule is enforced, attempt to get into communication with each other, the possibilities of trouble are obvious. All that may be said on this matter is that the person who calls another by telephone should extend that person the same courtesies that he would had he called him in person to his office; and that a person who is called by telephone by another should meet him with the same consideration as if he had received a personal call at his office or home. The arbitrary ruling made by some corporations and persons, which results always in the "other fellow's" doing the waiting, is not ethically correct nor is it good policy. =Private Branch Switchboards.= Private branch switchboards may be of common-battery or magneto types regardless of whether they work in conjunction with main office equipments having common-battery or magneto equipments. Usually a magneto private branch exchange works in conjunction with a magneto main office, but this is not always true. There are cases where the private branch equipment of modern common-battery type works in conjunction with main office equipment of the magneto type; and in some of these cases the private branch exchange has a much larger number of subscribers than the main office. This is likely to be true in large summer resort hotels located in small and otherwise unimportant rural districts. In one such case within our knowledge the private branch exchange has a larger number of stations than the total census population of the town, resulting in an apparent telephone development considerably greater than one hundred per cent. _Magneto Type._ Where both the private branch and the main office equipments are of the magneto type, the private branch requirements are met by a simple magneto switchboard of the requisite size, and the trunking conditions are met by ring-down trunks extending to the main office. In this case the supervision is that of the ordinary clearing-out drop type, the operators working together as best they may. _Common-Battery Type._ The cases where the private branch board is of common-battery type and the main office of magneto type are comparatively so few that they need not be treated here. Where they do occur they demand special treatment because the main portion of the traffic over the trunk lines to the city or town central office is likely to be toll traffic through that office over long-distance lines. The principal reason why the equipment of the town offices under such conditions is magneto rather than common battery is that the traffic conditions are those of short season and heavy toll, and common-battery switching equipment at the main office has no especial advantages for toll work. [Illustration: Fig. 438. Desk Type, Private Branch Board] For small private branch exchanges the desk type of switch board, shown in Fig. 438, is largely used. The operator frequently has other work to do and the desk is, therefore, a convenience. In larger private exchanges, such as those requiring more than one operator, some form of upright cabinet is employed, and if, as sometimes occurs, the branch exchange is of such size as to demand a multiple board, then the general form of the board does not differ materially from the standard types of multiple board employed in regular central office work. The most common private branch-exchange condition is that of a common-battery branch working into a common-battery main office. In such the main point to be considered is that of supervision of trunk-line connections. _Cord Type._ For the larger sizes of branch exchange switchboards, the switching apparatus is practically the same as that of ordinary manual switchboards wherein the connections are made between the various lines by means of pairs of cords and plugs. The private branch-exchange trunk lines usually terminate on the private branch board in jacks but in some cases plug-ended trunks are used. [Illustration: Fig. 439. Key Type, Private Branch Board] The line signals may consist in mechanical visual signals or in lamps, the choice between these depending largely on the source of battery supply at the branch exchange, a matter which will be considered later. The trunk-line signals at the private branch board are usually ordinary drops which are thrown when the main-exchange operator rings on the line as she would on an ordinary subscriber's line. Frequently, however, lamp signals are used for this purpose, being operated by locking relays energized when the main-office operator rings or, in some cases, operated at the time when the main-office operator plugs into the trunk-line jack. [Illustration: Fig. 440. Circuits, Key-Type Board] _Key Type._ For small private branch-exchange switchboards, a type employing no cords and plugs has come into great favor during recent years. Instead of connecting the lines by jacks and plugs, they are connected by means of keys closely resembling ordinary ringing and listening keys. Such a switchboard is shown in Fig. 439, this having a capacity of three trunks, seven local lines, and the equivalent of five cord circuits. The drops associated with the three trunks may be seen in the upper left-hand side of the face of the switchboard. Immediately below these in three vertical rows are the keys which are used in connecting the trunks with the "cord circuits" or connecting bus wires. At the right of the drop associated with the trunks are seven visual signals, these being the calling signals of the local lines. The seven vertical rows of keys, immediately to the right of the three trunk-line rows, are the line keys. The throwing of any one of these keys and of a trunk-line key in the same horizontal row in the same direction will connect a line with a trunk through the corresponding bus wires, leaving one of the supervisory visual signals, shown at the extreme top of the board, connected with the circuit. The keys in a single row at the right are those by means of which the operator may bridge her talking set across any of the "cord circuits." The circuits of this particular board are shown in Fig. 440. This is equipped for common-battery working, the battery feed wires being shown at the left. =Supervision of Private Branch Connections.= At the main office where common-battery equipment is used, the private branch trunks terminate before the _A_-operators exactly in the same way as ordinary subscribers' lines, _i. e._, each in an answering jack and lamp at one position and in a multiple jack on each section. It goes without saying, therefore, that the handling of a private branch call, either incoming or outgoing, should be done by the _A_-operator in the same manner as a call on an ordinary subscriber's line, and that the supervision of the connection should impose no special duties on the _A_-operator. There has been much discussion, and no final agreement, as to the proper method of controlling the supervisory lamp at the main office of a cord that is, at the time, connected to a private branch trunk. Three general methods have been practiced: The first method is to have the private branch subscriber directly control the supervisory lamp at the main office without producing any effect upon the private branch supervisory signal; this latter signal being displayed only after the connection has been taken down at the main office and in response to the withdrawal of the main office plug from the private branch jack. This is good practice so far as the main-office discipline is concerned but it results in a considerable disadvantage to both the city and private branch subscribers in that it is impossible for the private branch subscriber, when connected to the other, to re-signal the private branch operator without the connection being first taken down. The second method is to have the private branch subscriber control both the supervisory signal at the private branch board and at the main board. This has the disadvantage of bringing both operators in on the circuit when the private branch subscriber signals. The third method, and one that seems best, is to place the supervisory lamp of the private branch board alone under the control of the private branch subscriber, so that he may attract the attention of the private branch operator without disturbing the supervisory signal at the main office. The supervisory signal at the main office in this case is displayed only when the private branch operator takes down the connection. This practice results in a method of operation at the main office that involves no special action on the part of the _A_-operator. She takes down the connection only when the main-office subscriber has hung up his telephone and the private branch subscriber has disconnected from the trunk. Whatever method is employed, private branch disconnection is usually slow, and for this reason many operating companies instruct the _A_-operators to disconnect on the lighting of the supervisory lamp of the city subscriber. =With Automatic Offices.= Private branch exchanges most used in connection with automatic offices employ manual switchboards, with the cord circuits of which is associated a signal transmitting device by which the operator instead of the subscriber may manipulate the automatic apparatus of the public exchange by impulses sent over the private branch-exchange trunk lines. The subscriber's equipment at the private branch stations may be either automatic or manual. Frequently the same private branch exchange will contain both kinds. With the manual sub-station equipment the operation is exactly the same as in a private branch of a manual exchange, except that the private branch operator by means of her dial makes the central-office connection instead of telling the main-office operator to do so for her. With automatic sub-station equipment at the private branch the subscribers, by removing their receivers from their hooks, call the attention of the private branch operator, who may receive their orders and make the desired central-office connection for them, or who may plug their lines through to the central office and allow the subscribers to make the connection themselves with their own dials. In automatic equipment of the common-battery type, some change always takes place in the calling line at the time the called subscriber answers. In the three-wire system during the time of calling, both wires are of the same polarity with respect to earth. At the time of the answering of the called subscriber, the two wires assume different polarities, one being positive to the other. Such a change is sufficient for the actuation of devices local to the private exchange switchboard and may be interpreted through the calling supervisory signal in such a way as to allow it to glow during calling and not to glow after the called subscriber has answered. In the two-wire automatic system a similar change can be arranged for, with similar advantageous results. _Secrecy._ In private exchanges operating in connection with automatic central offices, the secret feature of individual lines may or may not be carried into the private exchange equipment. Some patrons of automatic exchanges set a high value on the absence of any operator in a connection and transact business over such lines which they would not transact at all over manual lines or would not transact in the same way over manual lines. To some such patrons, the presence of a private exchange operator, even though employed and supervised by themselves, seems to be a disadvantage. To meet such a feeling, it is not difficult to arrange the circuits of a private exchange switchboard so that the operator may listen in upon a cord circuit at any time and overhear what is being said upon it _so long as two subscribers are not in communication on that cord circuit_. That is, she may answer a call and may speak to the calling person at any time she wishes until the called person answers. When he does answer and conversation can take place, some device operates to disconnect her listening circuit from the cord circuit, not to be connected again until at least one of the subscribers has hung up his receiver. With private exchange apparatus so arranged, the secrecy of the system is complete. =Battery Supply.= There are three available methods of supplying direct current for talking and signaling purposes to private branch exchanges, each of which represents good practice under certain conditions. First, by means of pairs of wires extended from the central-office battery; second, by means of a local storage battery at the private branch exchange charged over wires from the central office; and third, by means of a local storage battery at the private exchange charged from a local source. The choice of these three methods depends always on the local conditions and it is a desirable feature, to be employed by large operating companies, to have all private branch-exchange switchboards provided with simple convertible features contained within the switchboard for adapting it to any one of these methods of supplying current. If a direct-current power circuit is available at the private branch exchange, it may be used for charging the local storage battery by inserting mere resistance devices in the charging leads. If the local power circuit carries alternating current, a converting device of some sort must be used and for this purpose, if the exchange is large enough to warrant it, a mercury rectifier is an economical and simple device. The supply of current to private branch exchanges over wires leading to the central-office battery has the disadvantage of requiring one or several pairs of wires in the cables carrying the trunk wires. No special wires are run, regular pairs in the paper insulated line or trunk cables being admirably suited for the purpose. Sufficient conductivity may be provided by placing several such pairs in multiple. If the amount of current required by the private exchange warrants it, pairs of charging wires from the central office may be fewer if a battery is charged over them than if they are used direct to the bus bars of the private exchange switchboard. If they are used in the latter way, and this is simpler for reasons of maintenance, some means must be provided to prevent the considerable resistance of the supply wires from introducing cross-talk into the circuit of the private exchange. This is accomplished by bridging a considerable capacity across the supply pairs at the private exchange--ten to twelve microfarads usually suffice. This point has already been referred to and illustrated in connection with Fig. 141. The number of pairs of wires, or, in other words, the amount of copper in the battery lead between the central office and the private branch-exchange switchboard needs to be properly determined not only to eliminate cross-talk when the proper condensers are used with them, but to furnish the proper difference of potential at the private exchange bus bars, so that the line and supervisory signals will receive the proper current. It is a convenience in installing and maintaining private exchange switchboards of this kind to prepare tables showing the number of pairs of No. 19 gauge and No. 22 gauge wires required for a private exchange at a given distance from its central office and of a probable amount of traffic. The traffic may be expressed in the maximum number of pairs of cords which will be in use at one time. With this fact and the distance, the number of pairs of wires required may be determined. =Ringing Current.= The ringing current may be provided in two ways: over pairs of wires from the city-office ringing machines or by means of a local hand generator, or both. A key should enable either of these sources of ringing current to be chosen at will. =Marking of Apparatus.= All apparatus should be marked with permanent and clear labels. That private exchange switchboard is best at which an almost uninformed operator could sit and operate it at once. It is not difficult to lay out a scheme of labels which will enable such a board to be operated without any detailed instructions being given. =Desirable Features.= The board should contain means of connecting certain of the local private exchange lines to the central-office trunks when the board is unattended. Also, it is desirable that it should contain means whereby any local private exchange line may be connected to the trunk so that its station will act as an ordinary subscriber's station. Whether the trunks of the private exchange lead to a manual or an automatic equipment, it often is desired to connect a local line through in that way, either so that the calling person may make his calls without the knowledge of the private exchange operator, because he wishes to make a large number of calls in succession, or because for some other reason he prefers to transact his business directly with or through the exchange than to entrust it to his operator. CHAPTER XXXV INTERCOMMUNICATING SYSTEMS =Definition.= The term "intercommunicating" has been given to a specialized type of telephone system wherein the line belonging to each station is extended to each of the other stations, resulting in all lines extending to all stations. Each station is provided with apparatus by means of which the telephone user there may connect his own telephone with the line of the station with which he wishes to communicate, enabling him to signal and talk with the person at that station. =Limitations.= The idea is simple. Each person does his own switching directly, and no operator is required. It is easy to see, however, that the system has limitations. The amount of line wire necessary in order to run each line to each station is relatively great, and becomes prohibitive except in exchanges involving a very small number of subscribers, none of which is remote from the others. Again, the amount of switching apparatus required becomes prohibitive for any but a small number of stations. As a result, twenty-five or thirty stations are considered the usual practical limit for intercommunicating systems. =Types.= An intercommunicating system may be either magneto or common-battery, according to whether it uses magneto or common-battery telephones. The former is the simpler; the latter is the more generally used. [Illustration: WESTERN ELECTRIC COMPANY BATTERY ROOM AT MONMOUTH, ILLINOIS] =Simple Magneto System.= The schematic circuit arrangement of an excellent form of magneto intercommunicating system is given in Fig. 441. In this, five metallic circuit lines are led to as many stations, an ordinary two-contact open jack being tapped off of each line at each station. A magneto bell of the bridging type is permanently bridged across each line at the station to which that line belongs. The telephone at each station is an ordinary bridging magneto set except that its bell is, in each case, connected to the line as just stated. Each telephone is connected through a flexible cord to a two-contact plug adapted to fit into any of the jacks at the same station. The operation is almost obvious. If a person at Station _A_ desires to call Station _E_, he inserts his plug into the jack of line _E_ at his station and turns his generator crank. The bell of Station _E_ rings regardless of where the plug of that station may be. The person at Station _E_ responds by inserting his own plug in the jack of line _E_, after which the two parties are enabled to converse over a metallic circuit. It makes no difference whether the persons, after talking, leave these plugs in the jacks or take them out, since the position of the plug does not alter the relation of the bell with the line. [Illustration: Fig. 441. Magneto Intercommunicating System] This system has the advantage of great simplicity and of being about as "fool proof" as possible. It is, however, not quite as convenient to use as the later common-battery systems which require no turning of a generator crank. =Common-Battery Systems.= In the more popular common-battery systems two general plans of operation are in vogue, one employing a plug and jacks at each station for switching the "home" instrument into circuit with any line, and the other employing merely push buttons for doing the same thing. These may be referred to as the plug type and the push-button type, respectively. [Illustration: Fig. 442. Plug Type of Common-Battery Intercommunicating System] _Kellogg Plug Type._ The circuits of a plug type of intercommunicating system, as manufactured by the Kellogg Company, are shown in Fig. 442. While only three stations are shown, the method of connecting more will be obvious. This system requires as many pairs of wires running to all stations as there are stations, and in addition, two common wires for ringing purposes. The talking battery feed is through retardation coils to each line. When all the hooks are down, each call bell is connected between the lower common wire and the tip side of the talking circuit individual to the corresponding station. The ringing buttons at each station are connected between the tip of the plug at that station and the upper common wire. As a result, when a person at one station desires to call another, it is only necessary for him to insert his plug in the jack of the desired station and press his ringing button; the circuit being traced from one pole of the ringing battery through the upper common ringing wire, ringing key of the station making the call, tip of plug, tip conductor of called station's line, bell of called station, and back to the ringing battery through the lower common ringing wire. [Illustration: Fig. 443. Push-Button Wall Set] _Kellogg Push-Button Type._ Fig. 443 shows a Kellogg wall-type intercommunicating set employing the push-button method of selecting, and Fig. 444 shows the internal arrangement of this set. [Illustration: Fig. 444. Push-Button Wall Set] _Western Electric System._ The method of operation of the push-button key employed in the intercommunicating system of the Western Electric Company is well shown in Fig. 445. When the button is depressed all the way down, as shown in the center cut of Fig. 445, which represents the ringing position of the key, contact is made with the line wires of the station called, and ringing current is placed on the line. When the pressure is released, the button assumes an intermediate position, as shown in the right-hand cut, which represents the talking position of the key and in which the ringing contacts _1_ and _2_ are open, but contact with the line for talking purposes is maintained. The key is automatically held in this intermediate position by locking plate _3_ until this plate is actuated by the operation of another button which releases the key so that it assumes its normal position as shown in the left-hand cut. When a button is depressed to call a station, it first connects the called station's line to the calling station through the two pairs of contacts _4_ and _5_ and then connects the ringing battery to that line by causing the spring _1_ to engage the contact _2_. The ringing current then passes through the bell at the called station, through the back contacts of the switch hook at that station, over one side of the line, and through the "way-down" contact _1_ of the button at the calling station, thence over the other side of the battery line back to the ringing battery, operating the bell at the called station. [Illustration: Fig. 445. Push-Button Action, Western Electric System] The circuits of the Western Electric system are similar to those of Fig. 442, but adapted, of course, to the push-button arrangement of switches. Two batteries are employed, one for ringing and the other for talking, talking current being fed to the lines through retardation coils to prevent interference or cross-talk from other stations which might be connected together at the same time. _Monarch System._ As the making of connections in an intercommunicating system is entirely in the hands of the user, it is desirable that the operation be simple and that carelessness on the part of the user result in as few evil effects as possible. For instance, the leaving of the receiver off its hook will, in many systems, result in such a drain on the battery as to greatly shorten its life. The system of the Monarch Company has certain distinctive features in this respect. It is of the push-button type and as in the system just discussed, one pressure of the finger on one button clears the station of previous connections, rings the station called, and establishes a talking connection between the caller's telephone and the line desired. In addition to this, the system is designed to eliminate battery waste by so arranging the circuits that the battery current does not flow through either called or calling instrument until a complete connection is made--the calling button down at one station, the home button down at the called station, and both receivers off the hook. It does not hurt the batteries, therefore, if one neglects to hang up his receiver. [Illustration: Fig. 446. Push-Button Wall Set] [Illustration: Fig. 447. Push-Button Action, Monarch System] Three views of the wall set of this system are shown in Fig. 446, which illustrates how both the door and the containing box are separately hinged for easy access to the apparatus and connecting rack. As in the Western Electric and Kellogg push-button systems, each push-button key has three positions, as shown in Fig. 447. The first button shows all the springs open, the normal position of the key. The second button is in the half-way or talking position with all the springs, except the ringing spring, in contact. The third button shows the springs all in contact, the condition which exists when ringing a station. The mechanical construction of the key is shown in Fig. 448. Each button has a separate frame upon which the springs are mounted. Any one of the frames with its group of contact springs may be removed without interfering with either the electrical or the mechanical operation of the others. This is a convenient feature, making possible the installation of as few stations as are needed at first, and the subsequent addition of buttons as other stations are added. [Illustration: Fig. 448. Push-Button Keys] The restoring feature is a horizontal metal carriage, in construction very much like a ladder--one round pressing against each key frame, due to the tension on the carriage exerted by a single flat spring. The plunger of each button is equipped with a shoulder, which normally is above the round of the ladder. When the button is operated, this shoulder presses against a round of the carriage forcing it over far enough so that the shoulder can slip by. The upper surface of the shoulder is flat, and on passing below the pin, allows the carriage to slip back into its normal position and the pin rests on the top of the shoulder holding the plunger down. This position places the talking springs in contact. The ringing springs are open until the plunger is pressed all the way down, then the ringing contact is made. When the pressure is released, the plunger comes back to the half-way or talking position, leaving the ringing contacts open again. When another button is pressed, the same operation takes place and, by virtue of the carriage being temporarily displaced, the original key is left free to spring back to its normal position. Each station is provided with a button for each other station and a "home" button. The salient feature of the system is that before a connection may be established, the button at the calling station corresponding to the station called and also the home button of the station called must be depressed, if it is not already down. The home key at any station, when depressed, transposes the sides of the line with respect to the talking apparatus. The home key also has a spring which changes the normal connection of the line at that station from the negative to the positive side of the talking battery. Unless, therefore, a connection between two stations is made through the calling key at one station and the home key at the other, no current can flow even though both receivers are off their hooks, because in that case no connection will exist with the positive side of the battery. This relation is shown in Fig. 449, which gives a simplified circuit arrangement for two connected stations. [Illustration: Fig. 449. Monarch Intercommunicating System] Referring to Fig. 449, when the station called depresses the home button the talking circuit is then completed after the hook switch is raised. This is because the talking battery is controlled by the home key. Conductors from both the negative and the positive sides of the battery enter this key. In the normal position of the springs, the negative side of the battery is in contact with the master spring in the home key and through these springs the negative battery is applied to all the calling keys, and from there on to the hook switch. When, however, the home button is operated, the spring which carries the negative battery to the home key is opened, and the spring which carries the positive battery is closed. This puts the positive battery on at the hook switch instead of the negative battery, as in its normal condition. In this system it is seen that a separate pair of line wires is used for each station, and in addition to these, two common pairs are run to all stations, one for ringing and one for talking battery connections. =For Private Branch Exchanges.= So far the intercommunicating system has been discussed only with respect to its use in small isolated plants. It has a field of usefulness in connection with city exchange work, as it may be made to serve admirably as a private branch exchange. Where this is done, one or more trunk lines leading to an office of the city exchange are run through the intercommunicating system exactly as a local line in that system, being tapped to a jack or push button at every station. A person at any one of the stations may originate a call to the main office by inserting his plug in the trunk jack, or pushing his trunk push button. Also any station, within hearing or sight of the trunk-line signal from the main office, may answer a main-office call in the same way. In order that the convenience of a private branch exchange may be fully realized, however, it is customary to provide an attendant's station at which is placed the drop or bell on which the incoming trunk signal is received. The duty of this attendant during business hours is to answer trunk calls from the main office and finding out what party is desired, call up the proper station on the intercommunicating system. The party at that station may then connect himself with the trunk. The practice of the Dean Company, for instance, is as follows in regard to trunking between intercommunicating systems and main offices with common-battery equipment. The attendant's station telephone cabinet contains, besides the push-button keys for local and trunk connections, a drop signal and release key, together with relays in each trunk circuit. The latter are used to hold the trunks until the desired party responds. The main-exchange trunk lines, besides terminating at the attendant's station, are wired through the complete intercommunicating system so that any intercommunicating telephone can be connected direct to the central office by depressing the trunk key, which is provided with a button of distinctive color. The pressing of the trunk key allows the telephone to take its current from the main-office storage battery and to operate the main-office line and supervisory signals direct, without making it necessary to call on the attendant to set up the connection. [Illustration: Fig. 450. Junction Box] [Illustration: Fig. 451. Typical Arrangement of Intercommunicating System] Incoming calls from the common-battery main office to the intercommunicating system are all handled by the attendant. The main-office operator signals the intercommunicating system by ringing, the same as for a regular subscriber's line. This will operate a drop in the attendant's station cabinet, and through an armature contact, give a signal on a low-pitched buzzer. This alarm buzzer operates only when the main exchange is ringing and, therefore, does not require that the drop shutter be restored immediately. An extra key may be provided for an extension night-alarm bell, for use where the attendant also does work in a room separate from that containing the attendant's station telephone equipment. The attendant operator answers the main-line signal by pressing the proper trunk button, as designated by the operated drop on the attendant's cabinet. The answering of the trunk connects a locking relay across the circuit so that the attendant may call the desired party on the intercommunicating system without having to hold the trunk manually. The party desired is then notified which trunk to use and the attendant operator hangs up her receiver, no further attention being necessary on her part. The trunk-holding relay is automatically released when the desired party (with the telephone receiver off the hook) depresses the proper trunk button, thus clearing the trunk line of all bridged apparatus and making the talking circuit the same as in the regular type of private branch-exchange switchboard. The most convenient way of installing the wires of an intercommunicating system is to run a cable containing the proper number of pairs to provide for the ultimate number of stations to all the stations, tapping off from the conductors in the cable to the jacks or push buttons at each station. These tap connections are best made by means of junction boxes which contain terminals for all the conductors. Such a junction box, with the through cable and the tap cable in place, is illustrated in Fig. 450. A schematic lay-out of the various parts of a Dean intercommunicating system, provided with an attendant's station and with trunks to a city office, is given in Fig. 451. CHAPTER XXXVI LONG-DISTANCE SWITCHING =Definitions.= Telephone messages between communities are called long-distance messages. They are also called toll messages. Almost all long-distance traffic is handled by message-rate (measured-service) methods of charge. All measured-service messages are toll messages, whether they are completed within a given community or between communities. The term "long-distance," therefore, is more descriptive than the term "toll." The subject of local and long-distance measured service is treated exhaustively in a chapter of its own. Some telephone-exchange operating companies call their own inter-city business "toll," and use the term "long-distance" for business carried between exchanges for them by another company. The distinction seems to be unwarranted. =Use of Repeating Coil.= Most long-distance lines are magneto circuits. If they are switched to grounded circuits, repeating coils need to be inserted. Toll switching equipments contain means of inserting repeating coils in the connecting cords when required. Their use reduces the volume of transmitted speech, but often is essential even in connecting metallic circuit lines, as a quiet local metallic circuit may have a ground upon it which will cause excessive noises when a quiet long-distance line is connected to it. =Switching through Local Board.= In the simplest form of long-distance switching, the lines terminate in switchboards with local lines and may be connected with each other and with the local lines through the regular cord circuits, if the equipment be of the magneto type. The waystations on such a line are equipped with magneto generators. These waystations may signal each other by bell ringing; the central office may call any waystation by ringing the proper signal and may supervise in a way all traffic on such lines by noting the calls for other stations than the supervising exchange. =Operators' Orders.= _By Call Circuits._ Where the long-distance traffic between two communities is large, economy requires that the sending of signals by ringing over the line, waiting for an answer, and then reciting the details of the call, be improved upon. If the traffic is large and the distance between communities small, call circuits are established in the same way as between the switchboards in several manual central offices of an exchange. The long-distance operator handling the originating call passes the necessary details to the distant operator by telephone over the call circuit. Such circuits also are known as order circuits. They are accessible to originating operators at keys and are connected directly and permanently to the telephone sets of receiving operators. One call circuit can handle the orders for a large number of actual conversation circuits. The operator at the receiving end designates the conversation circuit which shall be used, the originating operator following that instruction. _By Telegraph._ Where traffic and distance are large, conversation lines cost more than in the case last assumed. It then is of greater importance to use all the possible talking circuits for actual conversations in order that the revenue may be as high as possible. A phantom circuit good enough for call circuit purposes would be good enough for actual commercial messages, therefore, it is customary to furnish such originating and receiving operators with Morse telegraph sets. The lines are obtained by applying composite apparatus to the conversation circuits. Two Morse circuits can be had from each long-distance line without impairing any quality of that line except the ability to ring over it. As one Morse circuit can carry information enough between two operators to enable them to keep many telephone circuits busy, they do not need to ring upon the composited lines, so that nothing is lost while revenue is gained. =Two-Number Calls.= In cases where the traffic between communities is large, where the rate is small, and where the conversations are short and more on the general order of local calls, it is usual to handle the switches exactly as local calls are trunked between central offices of the same exchange. That is, the subscriber's operator who answers the call trunks it, by the assistance of a call circuit and an incoming trunk operator. The subscriber's operator records only the numbers of the calling and called subscribers. No long-distance operators at all assist in these connections. They are known as "two-number calls." The calling subscriber remains at his telephone until the conversation is finished. =Particular-Party-Calls.= In cases where the traffic is smaller, and where the rate is large, it is customary to handle the calls through long-distance operators. The ticket records the particular party wished, and the calls are named "particular party" calls. In such connections the calling patron is allowed to hang up his receiver, after his call is recorded, and is called again when his correspondent is found and is ready to talk. This makes _all calls for conversations_ outgoing ones. Only recording operators receive calls _from_ patrons. Line operators make calls _to_ patrons. =Trunking.= Long-distance lines entering a city usually terminate in one office only, no matter how many offices the local exchange may have. It is possible to terminate these long-distance lines on a position of the multiple switchboard for local lines. For a variety of reasons this is not practiced except in special cases. The usual method is to terminate them in a special long-distance board and to provide trunk lines from this board to the one or more local switchboards of the exchange. In common-battery systems these toll trunks are so arranged that the called local subscriber receives transmitter current from the office nearest to him, yet is able to show the long-distance operator the position of his switch hook and is able to be called by the long-distance operator without the intervention of the switching operator in the local office, even though two repeating coils may be in the trunk circuit. _Through Ringing._ There is a distinct traffic advantage in having the ringing of the subscriber under the control of the long-distance operator. The latter may call for the subscriber by stating her wish over the call circuit associated with the long-distance trunk. The connection having been made by the switching operator, the long-distance operator may withhold ringing the subscriber's bell until all is in readiness for the conversation. _High-Voltage Toll Trunks._ In some systems, the long-distance trunks are further specialized by being enabled to furnish transmitter current to subscribers at a higher voltage than is used in local conversations. With a given construction of transmitters there is a critical maximum current which can be carried by the granular carbon of the instrument without excessive heating, consequent noises, and permanent damage. The shortest lines and the longest lines of an exchange district being served by a source of current common to all, the standard potential of this source must be such as to give the longest lines current enough without giving the shortest lines too much. The very longest local lines, however, do not receive current enough from the standard potential to give maximum efficiency when talking over long distances, though they get enough for local conversations. By providing a battery with a voltage twice that used for local conversations and connecting it into the current supply element of the toll trunk through non-inductive resistances, not too much current may be given to the shortest lines and considerably more than normal current to the longest lines. =Ticket Passing.= When only one operator is necessary in a town, her duty being to switch both local and long-distance lines, she may write her own tickets and execute them entire. In larger communities with larger long-distance traffic, the duties need to be specialized. The subscribers' wants as to long-distance connections are given by themselves to recording long-distance operators, who write them on tickets and pass these to operators who get the parties together. The problem of ticket-passing becomes important and many mechanical carriers have been tried, culminating in the system which utilizes vacuum tubes. This is in some ways similar to vacuum or compressed-air tube systems for carrying cash in retail stores. The ticket is carried, however, without any enclosing case and the tubes are flat instead of round, _i. e._, they are rectangular in section. By suitable means a vacuum is maintained in a large common tube having a tap to a box-like valve at each line operator's position. A ticket tube connects this valve with a distributing table at or near which the tickets are written. The tickets are of uniform size and are so made as to enable a flap to be bent up easily along one edge. The distributing operator has merely to insert the ticket, bent edge foremost, in the open end of the tube, whereupon the air pressure behind it will drive it through to its destination, near by or far away. The tickets travel thirty feet a second. The tube may be bent into almost any required form. The ticket, on arriving at a line operator's position, slides between two springs, breaking a shunt around a relay and allowing the latter to light the lamp. =Waystations.= Waystations on long-distance lines may be equipped in several ways. Most of them have magneto sets and can ring each other. Some are equipped with common-battery sets and get all current for signaling and transmission from a terminal central office. In the latter case, there is the advantage that the ringers are in series with condensers, assisting greatly in tests for fault locations. Such tests are hindered by the presence of ringer bridges across the line, as in magneto practice. Condensers can be inserted in series with ringers of magneto sets if the testing advantage is valued highly enough. A disadvantage of the use of common-battery sets in waystations on long-distance lines is the lessened transmission volume of the stations farthest from the current source. _Center Checking._ An operating advantage of common-battery sets on long-distance lines is that all calls are forced to be answered by the terminal station. Waystations can not call each other, as they have no calling means. With magneto sets, waystation agents sometimes call each other direct and neglect to record the call and to remit its price. When they can not call each other direct, the revenues of the company increase. A traffic method which requires all calls from waystations to be made to a central switching office is called a center-checking system. It is so called because all checking for stations so switched is done at the central point instead of each waystation keeping its own records of calls sent and received. In such practice it is usual to bill each station once a month for the messages it sent. Where center checking is not practiced, the agent makes a report and sends a remittance. Center checking comes about naturally for waystations having no ringing equipment. Center checking originated long before the invention of common-battery systems. It requires merely that no waystation shall have a generator which can ring a bell. The method most widely used is to equip the waystations with magneto generators which produce direct currents only; such a generator cannot operate a polarized ringer. It is not usual to produce the direct current by actually rectifying the alternating current, but merely by omitting half the impulses, sending to the line only alternate half-cycles of the current generated. Any drop or relay adapted to respond to regular ringing current will respond to this modified form of generator. CHAPTER XXXVII TELEPHONE TRAFFIC The term "traffic," with reference to telephone service, has come to mean the gross transaction of communication between telephone users. This traffic may be expressed in whatever terms are found convenient for the particular phase considered. =Unit of Traffic.= With reference to payment for local telephone service, the conversation is the unit of traffic. In the daily operations of telephone systems there are fewer conversations than there are connections and fewer connections than there are calls, because lines are found busy and all calls to subscribers are not answered. For these reasons, in traffic inquiries which have to do with the amount of business which subscribers attempt to transact, the total traffic in a given time usually is considered as so many calls originated by the subscribers in the community. From this condition arises the term "originating calls." For the reason that the purpose of the switching equipment in a central office is to make connections, the abilities of operators and of equipments frequently are measured in terms of connections per hour or per other unit of time. For the reason that in charging for service all unavailing calls are omitted, the conversation is the unit of traffic. =Traffic Variations.= Telephone-exchange traffic is subject to such general variations as are noted in the way a compass needle points north, the migrations of birds, the blowing of the trade winds, and other natural phenomena. There are variations in traffic which occur each day, others which change with the seasons, and still others which are related to holidays and other special commercial and social events. For instance, the day before Thanksgiving Day, in many regions, is the busiest telephone traffic day in the year. [Illustration: WESTERN ELECTRIC MOTOR-GENERATOR CHARGING SET] The daily variations in telephone traffic are closely related to commercial activities and certain general features of this daily variation are common to all telephone systems everywhere. Fig. 452 is a typical graphic record of the traffic of a telephone exchange and represents what happens in almost every town or city. The total calls in this figure are not given as absolute units but would vary to adapt the figure to a particular case. The figure shows principally that the traffic in the night is light; that it rises to its maximum height somewhere between 10 o'clock A.M. and noon; that though it is never as high again during that day, the afternoon peak is over 80 per cent as great; and that two minor peaks appear about the dinner hour and after evening entertainments. [Illustration: Fig. 452. Load Curve] _Busy-Hour Ratio._ If the story told by Fig. 452 were to be turned into a table of calls per hour, the busiest hour of the day would be found to correspond to the highest portion of the figure, and in that busiest hour of the day, if a number of selected days were to be compared, would be found a very constant traffic. The number of calls made, or the number of connections completed, in that particular hour, day by day, would be found to be much the same. The ratio of the number of units in that hour to the number of units in that entire day would be found to be practically the same ratio day by day. This ratio of busy hour to total day would be found to be much more nearly constant than the gross number of calls per hour or per day. In a large, busy city, about one-eighth of the total daily calls are in some one hour; in a smaller, less active city, probably one-tenth are so congested. This is reasonable when one remembers that in the larger city the active business of the day begins later and ends earlier. =Importance of Traffic Study.= A knowledge of the amount of traffic in an exchange, and its distribution as to time and as to the divisions of the exchange, is important for a number of reasons. Traffic knowledge is essential in order that the equipment may be designed and placed in the proper way and the total load distributed properly on that apparatus and its operators. For example, in an office equipped with a manual multiple switchboard, the length of the switchboard is governed entirely by the number of operators who must work before it. It is mechanically possible to make a switchboard for ten thousand lines only 15 feet long, seating seven operators. The entire multiple of ten thousand lines could appear three times in such a switchboard. The seven operators could not handle the traffic we know would be originated by ten thousand lines, with any present system of charging for service. Even a rough knowledge of the probable traffic would enable us to approximate the number of operators needed and to equip each position, not only with access to the ten thousand lines to be called, but also with just enough keyboard equipment, serving as tools, and just enough answering jacks, serving as means of bringing the traffic to her. It is foreknowledge of traffic which enables a switchboard to fit the task it is to perform. =Rates of Calling.= The rates of calling of different kinds of lines vary. The lines of business stations originate more calls than do the lines of residences. Some kinds of business originate more calls than others. Some kinds of business have a higher rate of calling in one season than in others. Flat-rate lines originate more calls than do message-rate lines. When a line changes from a flat rate to a message rate, the number of originating calls per day decreases. An operator's position, handling message-rate lines only, can serve more lines than if all of them were at flat rates. The number of message-rate or coin-prepayment lines which an operator's position can care for depends not only on the traffic but on the method of charging for service, whether by tickets or meters and upon the kind of meters; or it depends on the method of collecting the coins. In some regions, the rate of calling, on the introduction of a complete measured-service plan, has been reduced to one-fourth of what it was on the flat-rate plan. In manual switchboards of early types, wherein the position of the subscriber's answering jack was fixed by his telephone number, the inequality of traffic became a serious problem. Most of the subscribers who first installed telephones when the exchange was small, retained their telephones and numbers; as their use of the telephone grew with their business, it was customary to find the positions answering the lower numbers much more busy than the positions answering the higher numbers, the latter belonging to later and usually less active business places. _Functions of Intermediate Distributing Frame._ The intermediate distributing board was invented to meet these conditions of unequal traffic upon lines and of variations in traffic with changes of seasons and of charges. The intermediate distributing board enables a line to retain its number and its position in the multiple, but to keep its answering jack and lamp signal in any desired position. If a flat-rate subscriber changes to a message rate, his line may be moved to a message-rate position and be answered, in company with others like it, by an operator serving many more lines than she could serve if all of them were flat rate. =Methods of Traffic Study.= The best way to learn traffic facts for the purposes of designing and operating equipment is to conduct systematic series of observations in all exchanges; to record them in company with all related facts; and to compare them from time to time, recording the results of the comparisons. Then when it is required to solve a new problem, the traffic data will enable the probable future conditions to be known with as great exactness as is possible in studies with relation to transportation or any other human activity. TABLE XIII Calling Rates +-------------------------+-------------------------------+ | | CALLS PER DAY WITH DIFFERENT | | KIND OF SERVICE | METHODS OF CHARGE | | +-------------+-----------------+ | | FLAT RATE | MESSAGE RATE | +-------------------------+-------------+-----------------+ |Residence | 8 | 4 | |Business | 12 to 20 | 8 to 14 | |Private Exchange Trunk | 40 | 25 | |Hotel Exchange Trunk | 50 | 30 | |Apartment House Trunk | 30 | 18 | +-------------------------+-------------+-----------------+ There are three general ways of observing traffic. A record of originating calls is known as a "peg count," because the counting formerly was done by moving a peg from place to place in a series of holes. The simplest exact way is to provide each operator with a small mechanical counter, the key of which she can depress once for each call to be counted. A second way is to determine a ratio which exists, for the particular time and place, between the number of calls in a given period and the average number of cord circuits in use. Knowing this ratio, the cord circuits can be counted, the ratio applied, and the probable total known. The third method, which is applicable to offices having service meters on all lines, is to associate one master meter per position or group of lines with all the meters of that position or group, so that each time any service meter of that position is operated, the master meter will count one unit. This method applies to either manual or automatic equipments. =Representative Traffic Data.= For purposes of comparison, the following are representative facts as to certain traffic conditions. _Calling Rates._ The number of calls originated per day by different kinds of lines with different methods of charge are shown in Table XIII. _Operators' Loads._ The abilities of subscribers' operators to switch these calls depend on the type of equipment used, on the kind of management exercised, and on the individual skill of operators. With manual multiple equipment of the common-battery type, and good management, the numbers of originating calls per busy hour given in Table XIV can be handled by an average operator. The number of calls per operator per busy hour depends upon the amount of trunking to other offices which that operator is required to do. In a small city, for example, where all the lines are handled by one switchboard, there is no local switching problem except to complete the connection in the multiple before each position. In a large city, where wire economy and mechanical considerations compel the lines to be handled by a number of offices with manual equipment, some portion of the total originating load of each office must be trunked to others. Table XIV shows that an increase of 90 per cent in the amount of out-trunking has decreased the operator's ability to less than 70 per cent of the possible maximum. TABLE XIV Effect of Out-Trunking on Operator's Capacity +----------------------------+---------------------------------------+ |PER CENT ORIGINATING CALLS | CAPACITY OF SUBSCRIBERS' OPERATOR'S | |TRUNKED TO OTHER OFFICES | POSITION IN CALLS PER BUSY HOUR | +----------------------------+---------------------------------------+ | 0 | 240 | | 10 | 230 | | 30 | 200 | | 50 | 185 | | 75 | 170 | | 90 | 165 | +----------------------------+---------------------------------------+ _Trunking Factor._ In providing the system of trunks interconnecting the offices, whether the equipment be manual or automatic, it is essential to know not only how much traffic originates in each office, but how much of it will be trunked to each other office and how many trunks will be required. An interesting phase of telephone traffic studies is that it is possible to determine in advance the amount of traffic which can be completed directly in the multiple of that office and how much must be trunked elsewhere. Theoretical considerations would indicate that if the local multiple contains one-eighth of the total lines of the city, one-eighth of the calls originating in that office could be completed locally and seven-eighths would be trunked out. In almost all cases, however, it is found that more than the theoretical percentage of originating calls are for the neighborhood of that office and can be completed in the multiple. This results in the determination of a factor by which the theoretical out-trunking can be multiplied to determine the probable real out-trunking. In most cases, the ratio of actual to theoretical out-trunking is 75 per cent, or approximately that. In special cases, it may be far from 75 per cent. _Trunk Efficiency._ The capacities of trunks vary with their methods of operation and with the number of trunks in a group. For example, in the manual system where trunk operators in distant offices are instructed over call circuits and make disconnections in response to lamp signals, such an incoming trunk operator can complete from 250 to 500 connections per busy hour. The actual ability depends upon the number of distant offices served by that operator and upon the amount of work she has to perform on each call. The number of messages which can be handled by one trunk in the busy hour will depend upon the number of trunks in the group and upon the system employed. It appears that the ability of trunks in this regard is higher in the automatic system than in the manual system. For the latter, Table XV gives representative facts. TABLE XV Messages per Trunk in Manual System +----------------------------+------------------------+ | NUMBER OF TRUNKS IN GROUP, | MESSAGES PER TRUNK PER | | MANUAL SYSTEM | BUSY HOUR | +----------------------------+------------------------+ | 5 | 7 | | 10 | 9 | | 20 | 12 | | 40 | 15 | | 60 | 18 | +----------------------------+------------------------+ Some of the reasons for the higher efficiencies of trunks in the automatic system are not well defined, but unquestionably exist. They have to do partly with the prompter answering observable in automatic systems. The operation of calling being simple, a called subscriber seems to fear that unless he answers promptly the calling party will disconnect and perhaps may call a competitor. The introduction of machine-ringing on automatic lines, where existing in competition with manual ringing on manual lines, seems to encourage subscribers to answer even more promptly. The length of conversation in automatic systems seems to be shorter than in manual systems. Still more important, disconnection in automatic systems is instantaneous during all hours, whereas in manual systems it is less prompt in the busiest and least busy hours than in the hours of intermediate congestion. The practical results of trunk efficiencies in automatic systems are given in Table XVI. TABLE XVI Messages per Trunk in Automatic System +----------------------------+------------------------+ | NUMBER OF TRUNKS IN GROUP, | MESSAGES PER TRUNK PER | | AUTOMATIC SYSTEM | BUSY HOUR | +----------------------------+------------------------+ | 5 | 15 | | 10 | 22 | | 20 | 28 | | 40 | 32 | | 60 | 34 | +----------------------------+------------------------+ _Toll Traffic._ Toll or long-distance traffic follows the general laws of local or exchange traffic. Conversations are of greater average length in long-distance traffic. The long-distance line is held longer for an average conversation than is a local-exchange line. The local trunks which connect long-distance lines with exchange lines for conversation are held longer than are the actual long-distance trunks between cities. Knowing the probable traffic to be brought to the long-distance switching center by the long-distance trunks from exchange centers, the number of trunks required may be determined by knowing the capacity of each trunk. These trunk capacities vary with the method of handling the traffic and they vary as do local trunks with the number of trunks in a group. Table XVII illustrates this variation of capacity with sizes of groups. TABLE XVII Messages per Trunk in Long-Distance Groups +--------------------------+-------------------------+ | NUMBER OF LONG-DISTANCE | MESSAGES PER TRUNK PER | | TRUNKS IN GROUP | BUSY HOUR | +--------------------------+-------------------------+ | 5 | 2 | | 10 | 3 | | 20 | 3.2 | | 40 | 3.5 | | 60 | 4 | | 100 | 4.6 | +--------------------------+-------------------------+ =Quality of Service.= The quality of telephone service rendered by a particular equipment managed in a particular way depends on a great variety of elements. The handling of the traffic presented by patrons is a true manufacturing problem. The quality of the service rendered requires continuous testing in order that the management may know whether the service is reaching the standard; whether the standard is high enough; whether the cost of producing it can be reduced without lowering the quality; and whether the patrons are getting from it as much value as they might. In manual systems, the quality of telephone service depends upon a number of elements. The following are some principal ones: 1. Prompt answering. 2. Prompt disconnection. 3. Freedom from errors in connecting with the called line. 4. Promptness in connecting with the called line. 5. Courtesy and the use of form. 6. Freedom from failure by busy lines and failure to answer. 7. Clear enunciation. 8. Team work. _Answering Time._ There is an interrelation between these elements. Team work assists both answering and prompt disconnection. The quality of telephone service can not be measured alone in terms of prompt answering. Formerly telephone service was boasted of as being "three-second service" if most of the originating calls were answered in three seconds. Often such prompt answering reacts to prevent prompt disconnecting. Patient, systematic work is required to learn the real quality of the service. As to answering, the clearest, truest statement concerning manual service is found by making test calls to each position, dividing them into groups of various numbers of whole seconds each, and comparing the percentage of these groups to the whole number of telephones to that position. For example, assume each of the calls to a given position to have been answered in ten seconds or less, in which 100 per cent are answered in ten seconds or less; 80 per cent in eight seconds or less; 60 per cent in six seconds or less. It is probable that a reasonably uniform manual service will show only a small percentage answered in three seconds or under. Such percentages may be drawn in the form of curves, so that at a glance one may learn efficiency in terms of prompt answering. _Disconnecting Time._ Prompt disconnection was improved enormously by the introduction of relay manual boards. Just before the installation of relay boards in New York City, the average disconnecting time was over seventeen seconds. On the completion of an entire relay equipment, the average disconnecting time was found to be under three seconds. The introduction of relay manual apparatus has led subscribers to a larger traffic and to the making of calls which succeed each other very closely. A most important rule is, _that disconnect signals shall be given prompt attention either by the operator who made the connection, by an operator adjacent, or by a monitor who may be assisting_; and another, still more important one is, _that a flashing keyboard lamp indicating a recall shall be given precedence over all originating and all other disconnect signals_. _Accuracy and Promptness._ Promptness and accuracy in connecting with the called line are vital, and yet a large percentage of errors in these elements might exist in an exchange having a very high average speed of answering the originating call. Indeed, it seems quite the rule that where the effort of the management is devoted toward securing and maintaining extreme speed of original answering, all the other elements suffer in due proportion. _Courtesy and Form._ It goes without saying that operators should be courteous; but it is necessary to say it, and keep saying it in the most effective form, in order to prevent human nature under the most exasperating circumstances from lapsing a little from the standard, however high. The use of form assists both the operators and the subscribers, because in all matters of strict routine it is much easier to secure high speed and great accuracy by making as many as possible of the operations automatic. The use of the word "number" and other well-accepted formalities has assisted greatly in securing speed, clear understanding, and accurate performance. The simple expedient of spelling numbers by repeating the figures in a detached form--as "1-2-5" for 125--has taught subscribers the same expedient, and the percentage of possible error is materially reduced by going one step further and having the operator, in repeating, use always the opposite form from that spoken by the calling subscriber. _Busy and Don't Answer Calls._ Notwithstanding the old impression of the public to the contrary, the operator has no control over the "busy line" and "don't answer" situation. It is, however, of high importance that the management should know, by the analysis of repeated and exhaustive tests of the service, to what extent these troubles are degrading it. In addition to improving the service by the elimination of busy reports, there is no means of increasing revenue which is so easy and so certain as that which comes from following up the tabulated results of busy calls. _Enunciation._ It must be remembered that clear enunciation for telephone purposes is a matter wholly relative, and the ability of an operator in this regard can be determined only by a close analysis of many observations from the standpoint of a subscriber. A trick of speech rather than a pleasant voice and an easy address has made the answering ability of many an operator captivating to a group of satisfied subscribers. _Team Work._ By team work is meant the ability of a group of operators, seated side by side, to work together as a unit in caring for the service brought to them by the answering jacks within their reach. In switchboards of the construction usual today, a call before any operator may be answered by her, or by the operator at either the right or the left of her position. In many exchanges this advantage is wholly overlooked. In the period of general re-design of central-office equipments about fourteen years ago, a switchboard was installed with mechanical visual signals and answering-jacks on a flat-top board, and an arrangement of operators such that the signal of any call was extremely prominent and in easy reach of each one of four or possibly five operators. Associated with the line signals within the reach of such a group was an auxiliary lamp signal which would light when a call was made by any of the lines so terminating. It was found that with this arrangement the calls were answered in a strictly even manner, special rushes being cared for by the joint efforts of the group rather than serving to swamp the operator who happened to be in charge of the particular section affected by the rush. This principle has been tried out in so many ways that it is astonishing that it is not recognized as being a vital one. The whole matter is accomplished by impressing upon each operator that her duty is, _not_ to answer the calls of a specific number of lines before her, but to answer, with such promptness as is possible, _any call which is within the reach of her answering equipment_. =Observation of Service.= All that is required to be known concerning the form of address and courtesy may be learned by a close observation of the operators' work by the chief operators and monitors, and by the use of listening circuits permanently connected to the operators' sets. It is naturally necessary that the use of these listening circuits by the chief operator or her assistants must not be known to the operators at the times of use, even though they may know of the existence of such facilities. With a well-designed and properly maintained automatic equipment, the eight elements of good manual service reduce themselves to only one or two. Freedom from failure by busy lines and failure to answer are service-qualities independent of the kind of switching apparatus. Too great a percentage of busy calls for a given line indicates that the telephone facilities for calls incoming to that subscriber are inadequate. The best condition would be for each subscriber to have lines enough so that none of them ever would be found busy. This is the condition the telephone company tries to establish between its various offices. In manual practice it is possible to keep such records as will enable the traffic department to know when the lines to a subscriber are insufficient for the traffic trying to reach him. As soon as such facts are known, they can be laid before the subscriber so that he may arrange for additional incoming lines. In automatic practice this is not so simple, as the source and destination of traffic in general is not so clearly known to the traffic department. Automatic recorders of busy calls are necessary to enable the facts to be tabulated. CHAPTER XXXVIII MEASURED SERVICE In the commercial relation between the public and a telephone system, the commodity which is produced by the latter and consumed by the former is telephone service. Users often consider that payment is made for rental of telephone apparatus and to some persons the payment per month seems large for the rental of a mere telephone which could be bought outright for a few dollars. The telephone instrument is but a small part of the physical property used by a patron of a telephone system. Even the _entire_ group of property elements used by a patron in receiving telephone service represents much less than what really is his proportion of the service-rendering effort. What the patron receives is service and its value during a time depends largely on how much of it he uses in that time, and less on the number of telephones he can call. _The cost of telephone service varies as the amount of use._ It is just, therefore, that the selling price should vary as the amount of use. =Rates.= There are two general methods of charging for telephone service and of naming rates for this charge. These are called flat rates and measured-service rates. The latter are also known as message rates, because the message or conversation is the unit. Flat rates are those which are also known as rentals. The service furnished under flat rates is also known as unlimited service, for the reason that under it a patron pays the same amount each month and is entitled to hold as many conversations--send as many messages and make as many calls--as he wishes, without any additional payment. In the measured-service plan, the amount of payment in a month varies in some way with the amount of use, depending on the plan adopted. The patron may pay a fixed base amount per month, entitling him to have equipment for telephone service and to receive messages, but being required to pay, in addition to this base amount, a sum which is determined by the number of messages which he sends. Or he may pay a base amount per month and be entitled to have the equipment, to receive calls, and to send a certain number of messages, paying specifically in addition only for messages exceeding that certain number. Whether flat rates or measured-service rates are practiced, the general tendency is to establish lower rates for service in homes than in business places. This is another recognition of the justice of graduating the rates in accordance with the amount of use. =Units of Charging.= While both the flat-rate and the measured-rate methods of charging for unlimited and measured service are practiced in local exchanges, long-distance service universally is sold at message rates. The unit of message rates in long-distance service is time. The charge for a message between two points joined by long-distance lines usually is a certain sum for a conversation three minutes long plus a certain sum for each additional minute or fraction of a minute. In local service, the message-rate time charge per message takes less account of the time unit. The conversation is almost universally the unit in exchanges. Some managements restrict messages of multi-party lines to five minutes per conversation, because of the desire to avoid withholding the line from other parties upon it for too long periods. Service sold at public stations similarly is restricted as to time, even though the message be local to the exchange. Three to five minutes local conversation is sold generally for five cents in the United States. The time of the average local message, counting actual conversation time only, is one hundred seconds. =Toll Service.= _Long Haul._ In long-distance service, there are two general methods of handling traffic, as to the relations between the calling and the called stations. For the greater distances, as between cities not closely related because not belonging to one general community, the calling patron calls a particular person and pays nothing unless he holds conversation with that person. In this method, the operator records the name of the person called for; the name, telephone number, or both, of the person calling; the names of the towns where the message originated and ended; the date, the time conversation began, and the length of time it lasted. _Short Haul._ Where towns are closely related in commercial and social ways and where the traffic is large and approaches local service in character, and yet where conversations between them are charged at different rates than are local calls within them, a more rapid system of toll charging than that just described is of advantage. In these conditions, patrons are not sold a service which allows a particular party to be named and found, nor is the identity of the calling person required. The operator needs to know merely of these calls that they originate at a certain telephone and are for a certain other. The facts she must record are fewer and her work is simpler. Therefore, the cost of such switching is less than for true long-distance calls and it can be learned by careful auditing just when traffic between points becomes great enough to warrant switching them in this way. Such switching, for example, exists between New York and Brooklyn, between Chicago and suburbs around it which have names of their own but really are part of the community of Chicago, and between San Francisco and other cities which cluster around San Francisco Bay. Calls of the "long-haul" class are known as "particular person" or "particular party" calls, while "short-haul" calls are known as "two-number" long-distance calls. It is customary to handle particular party calls on long-distance switchboards and to handle two-number calls in manual systems on subscribers' switchboards exactly like local calls, except that the two-number calls are ticketed. It is customary in automatic systems to handle two-number calls by means of the regular automatic equipment plus ticketing by a suburban or two-number operator. _Timing Toll Connections._ It formerly was customary to measure the time of long-distance conversations by noting on the ticket the time of its beginning and the time of its ending, the operator reading the time from a clock. For human and physical reasons, such timing seems not to be considered infallible by the patron who pays the charge, and in cases of dispute concerning overtime charges so timed, telephone companies find it wisest to make concessions. The physical cause of error in reading time from a clock is that of parallax; that is, the error which arises from the fact that the minute hand of a clock is some distance from the surface of the dial so that one can "look under it." On an ordinary clock having a large face and its minute hand pointing upward or downward, five people standing in a row could read five different times from it at the same instant. The middle person might see the minute hand pointing at 6, indicating the time to be half-past something; whereas, person No. 1 and person No. 5 in the row might read the time respectively 29 and 31 minutes past something. Operators far to the right or to the left of a clock will get different readings, and an operator below a clock will get different kinds of readings at different times and correct readings at few times. Timing Machines:--Machines which record time directly on long-distance tickets are of value and machines which automatically compute the time elapsing during a conversation are of much greater value. The calculagraph is a machine of the latter class. The use of some such machine uniformly reduces controversy as to time which really elapsed. Parallax errors are avoided. The record possesses a dignity which carries conviction. [Illustration: Fig. 453. Calculagraph Records] Calculagraph records are shown in Fig. 453. In the one shown in the upper portion of this figure, the conversation began at 10.44 P.M. This is shown by the right-hand dial of the three which constitute the record. The minutes past 10 o'clock are shown by the hand within the dial and the hour 10 is shown by the triangular mark just outside the dial between X and XI. The duration of the conversation is shown by the middle and the left-hand dials. The figures on both these dials indicate minutes. The middle dial indicates roughly that the conversation lasted for a time between 0 and 5 minutes. The left-hand dial indicates with greater exactness that the conversation lasted one and one-quarter minutes. The hand of the left-hand dial makes one revolution in five minutes; of the middle dial, one revolution in an hour. The middle dial tells how many full periods of five minutes have elapsed and the left-hand dial shows the excess over the five-minute interval. The lower portion of Fig. 453 is a similar record beginning at the same time of day, but lasting about five and one-half minutes. As before, the readings of the two dials are added to get the elapsed time. [Illustration: Fig. 454. Relative Position of Hands and Dials] The right-hand dial, showing merely time of day, stands still while its hands revolve. The dies which print the dials and hands of the middle and the left-hand records rotate together. Examining the machine, one finds that the hands of these dials always point to zero. The middle dial and hand make one complete revolution in an hour; the left-hand dial and hand, one in five minutes. In making the records, the dials are printed at the beginning and the hands at the end of the conversation. Therefore, the hands will have moved forward during the conversation--still pointing to zero in both cases--but when printed the hands will point to some other place than they were pointing when the dials were printed. In this way, their angular distances truly indicate the lapse of time. Fig. 454 shows the relative position of the hands and dials within the machine at all times. It will be noted that the arrow of the left-hand dial does not point exactly to zero. This is due to the fact that the dials and hands are printed by separate operations and cannot be printed simultaneously. [Illustration: WESTERN ELECTRIC RINGING MACHINE] Another method of timing toll connections has been developed by the Monarch Telephone Manufacturing Company. This employs a master clock of great accuracy, which may be mounted on the wall anywhere in the building or another building if desired. A circuit leads from this clock to a time-stamp device on the operator's key shelf, and the clock closes this circuit every quarter minute. The impulses thus sent over the circuit energize the magnet of the time stamp, which steps a train of printing wheels around so as always to keep them set in such position as to properly print the correct time on a ticket whenever the head of the stamp is moved by the operator into contact with the ticket. A large number of such stamps may be operated from the same master clock. By printing the starting time of a connection below the finishing time the computation of lapsed time becomes a matter of subtraction. A typical toll ticket with the beginning and ending time printed by the time stamp in the upper left-hand corner and the elapsed time recorded by hand in the upper right-hand corner is shown in Fig. 455. It is seen that this stamp records in the order mentioned the month, the day, the hour, the minute and quarter minute, the A.M. and P.M. division of the day, and the year. [Illustration: Fig. 455. Toll Ticket Used with Monarch System] An interesting feature of this system is that the same master clock may be made in a similar manner to actuate secondary clocks placed at subscribers' stations, the impulses being sent over wires in the same cables as those containing the subscribers' lines. This system, therefore, serves not only as a means for timing the toll tickets and operating time stamps wherever they are required in the business of the telephone company, but also to supply a general clock and time-stamp service to the patrons of the telephone company as a "by-product" of the general telephone business. Exchange service is measured in terms of conversations without much regard to their length. The payment for the service may be made at the time it is received, as in public stations and at telephones equipped with coin prepayment devices; or the calls from a telephone may be recorded and collection for them made at agreed intervals. In the prepayment method the price per call is uniform. In the deferred payment method the calls are recorded as they are made, their number summed up at intervals, and the amount due determined by the price per call. The price per call may vary with the number of calls sold. A large user may have a lower rate per call than a small user. =Local Service.= _Ticket Method._ Measured local service sometimes is recorded by means of tickets, similarly to the described method of charging long-distance calls, except that the time of day and the duration of conversation are not so important. Where local ticketing is practiced, it is usual to write on the ticket only the number of the calling telephone and the date, and to pass into the records only those tickets which represent actual conversations, keeping out tickets representing calls for busy lines and calls which were not answered. _Meter Method._ The requirements of speed in good local service are opposed to the ticketing method. Where measured service is supplied to a substantial proportion of the lines of a large exchange, electro-mechanical service meters are attached to the lines. These service meters register as a consequence of some act on the part of the switchboard operator, or may be caused to register by the answering of the called subscriber. [Illustration: Fig. 456. Connection Meter] In manual practice, meters of the type shown in Fig. 456 are associated with the lines as in Fig. 457. The meters are mounted separately from the switchboard, needing only to be connected to the test-strand of the line by cabled wires. If desired, the meter may be mounted on racks in quarters especially devoted to them, and the cases in which the racks are mounted may be kept locked. In such an arrangement the meters are read from time to time through the glass doors of the cases. The meters are caused to operate by pressure on the meter key _MK_, associated with the answering cord as in Fig. 458. This increases the normal potential to 30 volts. When the armature of the meter has made a part of its stroke, it closes a contact which places its 40-ohm winding in shunt with its 500-ohm winding, thus furnishing ample power for turning the meter wheels. [Illustration: Fig. 457. Western Electric Line Circuit and Service Meter] Such meters are in common use in large exchanges, notable examples being the cities of New York and London. In London, there is a zone within which the price per call is one penny and between which and other zones the price is twopence. Calls within the zone either are completed by the answering operator directly in the multiple before her or are trunked to other offices in that zone. Calls for points outside of that zone are trunked to other offices and in giving the order the operator finds that the call circuit key lights a special signal lamp before her. This reminds her that the call is at a twopence price, so in recording it she presses the meter key twice. This counts two units on the meter and the units are billed at a penny each. In automatic systems it is not possible to operate a meter system in which the operator will press a key for each call to be charged, because there is no operator. In such systems--a notable example being the measured-service automatic system in San Francisco--the meter registers only upon the answering of the called subscriber. Calls for lines found busy and calls which are not answered do not register. Calls for long-distance recording operators, two-number ticket operators, information, complaint, and other company departments are not registered. In the Chinatown quarter of San Francisco, where most calls begin and end in the neighborhood, service is sold at an unlimited flat rate for neighborhood calls and at a message rate for other calls. The meter system recognizes this condition and does not register calls _from_ Chinese subscribers _for_ Chinese subscribers, though it does register calls from Chinese subscribers to Caucasian subscribers. The nature of the system is such as to enable it to discriminate as to races, localities, or other peculiarities as may be desired. [Illustration: Fig. 458. Western Electric Cord Circuit and Service Meter Key] In the manual meter circuits of Figs. 457 and 458, the meter windings have no relation to the line conductors. In the automatic arrangement just described, there are meter windings in the line during times of calling, but none in the line during times of conversation. The balance of the line, therefore, is undisturbed at all times wherein balance is of any importance. In both systems just described, the meters of all lines are in their respective central offices. Meters for use at subscribers' stations have been devised and there is no fundamental reason why the record might not be made at the subscriber's station instead of, or in addition to, a central-office record. Experience has shown that confidence in a meter system can be secured if the meters be positive, accurate, and reliable. The labor of reading the meters is much less when they are kept in central offices. Subscribers may have access to them if they wish. _Prepayment Method._ Prepayment measured-service mechanisms permit a coin or token to be dropped into a machine at the subscriber's telephone at the time the conversation is held. A variety of forms of telephone coin collectors are in use, their operations being fundamentally either electrical or mechanical. Electrically operated coin collectors require either that the coin be dropped into the machine in order to enable the central office to be signaled in manual systems, or the switches to be operated in automatic systems, or they require that the coin be dropped into the machine after calling, but before the conversation is permitted. Western Electric Company coin collectors, shown in Fig. 459, may be operated in either way in connection with manual systems. The usual way is to require the coin to be dropped before the central-office line lamp can glow. The operator then rings the called subscriber and upon his answering places a sufficient potential upon the calling line to operate the polarized relay and to drop the coin into the cash box. If the called subscriber does not answer or his line is busy, potential is placed on the calling line, moving the polarized relay in the other direction and dropping the coin into a return chute so that the subscriber may take it. If it is preferred that the coin be paid only on the request of the operator, the return feature need not be provided. In both forms of operation, the Western Electric coin collector is adapted to bridge its polarized relay between one limb of the line and ground during the time a coin rests on the pins, as shown in Fig. 459. When no coin is on the pins--_i. e._, before calling and after the called station responds--the relay is not so bridged. [Illustration: Fig. 459. Principle of Western Electric Coin Collector] The armature of the relay responds only to a high potential and this is applied by the operator. If the coin is to be taken by the company, one polarity is sent; if it is to be returned to the patron, the other polarity is sent. These polarities are applied to a limb of the line proper. It will be recalled that pressures to actuate service meters are applied to the test-strand. If wished, keys may be arranged so as to apply 30 volts to the test-strand and the collecting potential to the line at the same operation. This enables the service meter to count the tokens placed in the cash box of the coin collector, and serves as a valuable check. In automatic systems, in one arrangement, coin collectors are arranged so that no impulses can be sent unless a coin has been deposited, the coin automatically passing to the cash box when the called subscriber answers, or to the patron if it is not answered. In another arrangement, calls are made exactly as in unlimited service, but a coin must be deposited before a conversation can be held. The calling person can hear the called party speak and may speak himself but can not be heard until the coin is deposited. No coin-return mechanism is required in this method. Coin collectors of these types usually are adapted to receive only one kind of coin, these, in the United States, being either nickels or dimes. For long-distance service, where the charges vary, it is necessary to signal to an operator just what coins are paid. It is uniformly customary to send these signals by sound, the collector being so arranged that the coins strike gongs. In coin collectors of the Gray Telephone Paystation Company, the coins strike these gongs by their own weight in falling through chutes. In coin collectors of the Baird Electric Company, the power for the signals is provided by hand power, a lever being pulled for each coin deposited. Both methods are in wide use. CHAPTER XXXIX PHANTOM, SIMPLEX, AND COMPOSITE CIRCUITS =Definitions.= Phantom circuits are arrangements of telephone wires whereby more working, non-interfering telephone lines exist than there are sets of actual wires. When four wires are arranged to provide three metallic circuits for telephone purposes, two of the lines are physical circuits and one is a phantom circuit. Simplex and composite circuits are arrangements of wires whereby telephony and telegraphy can take place at the same time over the same wires without interference. [Illustration: Fig. 460. Phantom Circuit] =Phantom.= In Fig. 460 four wires join two offices. _RR_ are repeating coils, designed for efficient transforming of both talking and ringing currents. The devices marked _A_ in this and the following figures are air-gap arresters. Currents from the telephones connected to either physical pair of wires pass, at any instant, in opposite directions in the two wires of the pair. The phantom circuit uses one of the physical pairs as a _wire_ of its line. It does this by tapping the middle point of the line side of each of the repeating coils. The impedance of the repeating-coil winding is lowered because, all the windings being on the same core, the phantom line currents pass from the middle to the outer connections so as to neutralize each other's influence. The currents of the phantom circuit, unlike those of the physical circuits, are _in the same direction_ in both wires of a pair at any instant. Their potentials, therefore, are equal and simultaneous. A phantom circuit is formed most simply when both physical lines end in the same two offices. If one physical line is longer than the other, a phantom circuit may be formed as in Fig. 461, wherein the repeating coil is inserted in the longer line where it passes through a terminal station of the shorter. [Illustration: Fig. 461. Phantom from Two Physical Circuits of Unequal Length] [Illustration: Fig. 463. Two Phantoms Joined by Physical Circuit] A circuit may be built up by adding a physical circuit to a phantom. A circuit may be made up of two or more phantom circuits, joined by physical ones. In Fig. 462 a phantom circuit is extended by the use of a physical circuit, while in Fig. 463, two phantom circuits are joined by placing between them a physical circuit. [Illustration: Fig. 462. Phantom Extended by Physical Circuit] _Transpositions._ In phantom circuits formed merely by inserting repeating coils in physical circuits and doing nothing else, an exact balance of the sides of the phantom circuit is lacking. The resistances, insulations, and capacities to earth of the sides may be equal, but the exposures to adjacent telephone and telegraph circuits and to power circuits will not be equal unless the phantom circuits are transposed. To transpose a set of lines of two physical wires each, is not complicated, though it must be done with care and in accordance with a definite, foreknown plan. Transposing phantom circuits is less simple, however, as four wires per circuit have to be transposed, instead of two. [Illustration: Fig. 464. Transposition of Phantom Circuits] In Fig. 464, the general spacing of transposition sections is the usual one, 1,300 feet, of the _ABCB_ system widely in use. The pole circuit, on pins _5_ and _6_ of the upper arm, is transposed once each two miles. The pole circuit of the second arm transposes either once or twice a mile. But neither pole circuit differs in transposition from any other regular scheme except in the frequency of transposition. All the other wires of each arm, however, are so arranged that each wire on either side of the pole circuit moves from pin to pin at section-ends, till it has completed a cycle of changes over all four of the pins on its side. In doing so, each phantom circuit is transposed with proper regard to each of the other three on that twenty-wire line. The "new transposition" lettering in Fig. 464 is for the purpose of identifying the exact scheme of wiring each transposition pole. The complication of wiring at each transposition pole is increased by the adoption of phantom circuits. Maintenance of all the circuits is made more costly and less easy unless the work at points of transposition is done with care and skill. Phantom circuits, to be always successful, require that the physical circuits be balanced and kept so. _Transmission over Phantom Circuits._ Under proper conditions phantom circuits are better than physical circuits, and in this respect it may be noted that some long-distance operating companies instruct their operators always to give preference to phantom circuits, because of the better transmission over them. The use of phantom circuits is confined almost wholly to open-wire circuits; and while the capacity of the phantom circuit is somewhat greater than that of the physical circuit, its resistance is considerably smaller. In the actual wire the phantom loop is only half the resistance of either of the physical lines from which it is made, for it contains twice as much copper. The resistance of the repeating coils, however, is to be added. =Simplex.= Simplex telegraph circuits are made from metallic circuit telephone lines, as shown in Fig. 465. The principle is identical with that of phantom telephone circuits. The potentials placed on the telephone line by the telegraph operations are equal and simultaneous. They cause no current to flow _around_ the telephone loop, only _along_ it. If all qualities of the loop are balanced, the telephones will not overhear the telegraph impulses. In the figure, _AA_ are arresters, as before, _GG_ are Morse relays; a 2-microfarad condenser is shunted around the contact of each Morse key _F_ to quench the noises due to the sudden changes on opening the keys between dots and dashes. [Illustration: Fig. 465. Simplex Telegraph Circuit] A simplex arrangement even more simple substitutes impedance coils for the repeating coils of Fig. 465. The operation of the Morse circuit is the same. An advantage of such a circuit, as shown in Fig. 466, is that the telephone circuit does not suffer from the two repeating-coil losses in series. A disadvantage is, that in ringing on such a line with a grounded generator, the Morse relays are caused to chatter. [Illustration: Fig. 466. Simplex Telegraph Circuit] The circuit of Fig. 465 may be made to fit the condition of a through telephone line and a way telegraph station. The midway Morse apparatus of Fig. 467 is looped in by a combination of impedance coils and condensers. The plans of Figs. 465 and 466 here are combined, with the further idea of stopping direct and passing alternating currents, as is so well accomplished by the use of condensers. [Illustration: Fig. 467. Simplex Circuit with Waystation] [Illustration: Fig. 468. Composite Circuit] =Composite.= Composite circuits depend on another principle than that of producing equal and simultaneous potentials on the two wires of the telephone loop. The opposition of impedance coils to alternating currents and of condensers to direct currents are the fundamentals. The early work in this art was done by Van Rysselberghe, of Belgium. In Fig. 468, one telephone circuit forms two Morse circuits, two wires carrying three services. Each Morse circuit will be seen to include, serially, two 50-ohm impedance coils, and to have shunts through condensers to ground. The 50-ohm coils are connected differentially, offering low consequent impedance to Morse impulses, whose frequency of interruption is not great. As the impedance coils are large, have cores of considerable length, and are wound with two separate though serially connected windings each, their impedance to voice currents is great. They act as though they were not connected differentially, so far as voice currents are concerned. Because of the condensers serially in the telephone line, voice currents can pass through it, but direct currents can not. Impulses due to discharges of cores, coils, and capacities in the Morse circuit _could_ make sounds in the telephones, but these are choked out, or led to earth by the 30-ohm impedance coils and the heavy Morse condensers. =Ringing.= Ringing over simplex circuits is done in the way usual where no telegraph service is added. Both telegraphy and telephony over simplex circuits follow their usual practice in the way of calling and conversing. In composite working, however, ringing by usual methods either is impossible because of heavy grounds and shunts, or if it is possible to get ringing signals through at all, the relays of the Morse apparatus will chatter, interfering with the proper use of the telegraph portion of the service. It is customary, therefore, either to equip composite circuits with special signaling devices by which high-frequency currents pass over the telephone circuits, operating relays which in turn operate local ringing signals; or to refrain from ringing on composite circuits and to transmit orders for connections by telegraph. The latter is wholly satisfactory over composite lines between points having heavy telegraph traffic, and it is between such points as these that composite practice is most general. =Phantoms from Simplex and Composite Circuits.= Phantom and simplex principles are identical, and by adding the composite principle, two simplex circuits may have a phantom superadded, as in Fig. 469. Similarly, as in Fig. 470, two composite circuits can be phantomed. This case gives seven distinct services over four wires: three telephone loops--two physical and one phantom--and four Morse lines. [Illustration: Fig. 469. Phantom of Two Simplex Circuits] [Illustration: Fig. 470. Phantom of Two Composite Circuits] =Railway Composite.= The foregoing are problems of making telegraphy a by-product of telephony. With so many telegraph wires on poles over the country, it has seemed a pity not to turn the thing around and provide for telephony as a by-product of telegraphy. This has been accomplished, and the result is called a railway composite system. For the reason that the telegraph circuits are not in pairs, accurately matched one wire against another, and are not always uniform as to material, it has not been possible to secure as good telephone circuits from telegraph wires as telegraph circuits from telephone wires. Practical results are secured by adaptation of the original principle of different frequencies. A study of Fig. 468 shows that over such a composite circuit the usual method of ringing from station to station over the telephone circuit by an alternating current of a frequency of about sixteen per second is practically impossible. This is because of the heavy short-circuit provided by the two 30-ohm choke coils at each of the stations, the heavy shunt of the large condensers, and the grounding through the 50-ohm choke coils. If high-frequency speech currents can pass over these circuits with a very small loss, other high-frequency circuits should find a good path. There are many easy ways of making such currents, but formerly none very simple for receiving them. Fig. 471 shows one simple observer of such high-frequency currents, it being merely an adaptation of the familiar polarized ringer used in every subscriber's telephone. In either position of the armature it makes contact with one or the other of two studs connected to the battery, so that in all times of rest the relay _A_ is energized. When a high-frequency current passes through this polarized relay, however, there is enough time in which the armature is out of contact with either stud to reduce the total energy through the relay _A_ and allow its armature to fall away, ringing a vibrating bell or giving some other signal. [Illustration: Fig. 471. Ringing Device for Composite Circuits] Fig. 472 shows a form of apparatus for producing the high-frequency current necessary for signaling. It is evident that if a magneto generator, such as is used in ordinary magneto telephones, could be made to drive its armature fast enough, it also might furnish the high-frequency current necessary for signaling through condensers and past heavy impedances. [Illustration: Fig. 472. Ringing Current Device] Applying these principles of high-frequency signals sent and received to a single-wire telegraph circuit, the arrangement shown in Fig. 473 results, this being a type of railway composite circuit. The principal points of interest herein are the insertion of impedances in series with the telegraph lines, the shunting of the telegraph relays by small condensers, the further shunting of the whole telegraph mechanism of a station by another condenser, and thus keeping out of the line circuit changes in current values which would be heard in the telephones if violent, and might be inaudible if otherwise. [Illustration: Fig. 473. Railway Composite Circuit] [Illustration: FRONT OF LONG-DISTANCE POWER BOARD U.S. Telephone Company, Cleveland, Ohio. _The Dean Electric Co._] A further interesting element is the very heavy shunting of the telephone receiver by means of an inductive coil. This shunt is applied for by-path purposes so that heavy disturbing currents may be kept out of the receiver while a sufficient amount of voice current is diverted through the receiver. It is well to have the inductance of this shunt made adjustable by providing a movable iron core for the shunt winding. When the core is drawn out of the coil, its impedance is diminished because the inductance is diminished. This reduces the amount of disturbing noise in the receiver. The core should be withdrawn as little as the amount of disturbance permits, as this also diminishes the loudness of the received speech. Because the signaling over lines equipped with this form of composite working results in the ringing of a bell by means of local current, it is of particular advantage in cases where the bell needs to ring loudly. Switch stations, crossings, and similar places where the attendant is not constantly near the telephone can be equipped with this type of composite apparatus and it so offers a valuable substitute for regular railway telegraph equipment, with which the attendant may not be familiar. The success of the local bell-ringing arrangement, however, depends on accurate relay adjustment and on the maintenance of a primary battery. The drain on the ringing battery is greater than on the talking battery. A good substitute for the bell signal on railway composite circuits is a telephone receiver responding directly to high-frequency currents over the line. The receiver is designed specially for the purpose and is known as a "howler." Its signal can be easily heard through a large room. The condenser in series with it is of small capacity, limiting the drain upon the line. Usually the howler is detached by the switch hook during conversation from a station. _Railway Composite Set._ The circuit of a set utilizing such an arrangement together with other details of a complete railway composite set is shown in Fig. 474. The drawing is arranged thus, in the hope of simplifying the understanding of its principles. It will be seen that the induction coil serves as an interrupter as well as for transmission. All of the contacts are shown in the position they have during conversation. The letters _Hc1_, _Hc2_, etc., and _Kc1_, _Kc2_, etc., refer to hook contacts and key contacts, respectively, of the numbers given. The arrangements of the hook and key springs are shown at the right of the figure. _RR_ represent impedance coils connected serially in the line and placed at terminal stations. The composite telephone sets are bridged from the line to ground at any points between the terminal impedance coils. The direct currents of telegraphy are prevented from passing to ground through the telephone set during conversation by the 2-microfarad condenser which is in series with the receiver. They are prevented from passing to ground through the telephone set when the receiver is on the hook by a .05 microfarad condenser in series with the howler. The alternating currents of speech and interrupter signaling are kept from passing to ground at terminals by the impedance coils. Signals are sent from the set by pressing the key _K_. This operates the vibrator by closing contacts _Kc6_ and _Kc7_. The howler is cut off and the receiver is short-circuited by the same operation of the key. The impedance of the coil _I_ is changed by moving its adjustable core. [Illustration: Fig. 474. Railway Composite Set] =Applications.= A chief use of composite and simplex circuits is for ticket wire purposes. These are circuits over which long-distance operators instruct each other as to connecting and disconnecting lines, the routing of calls, and the making of appointments. One such wire will care for all the business of many long-distance trunks. The public also absorbs the telegraph product of telephone lines. Such telegraph service is leased to brokers, manufacturers, merchants, and newspapers. Railway companies use portable telephone adjuncts to telegraph circuits on trains for service from stations not able to support telegraph attendants, and in a limited degree for the dispatching of trains. Telephone train dispatching, however, merits better equipment than a railway composite system affords. CHAPTER XL TELEPHONE TRAIN DISPATCHING[A] It has been only within the past three few that the telephone has begun to replace the telegraph for handling train movements. The telegraph and the railroads have grown up together in this country since 1850, and in view of the excellent results that the telegraph has given in train dispatching and of the close alliance that has always naturally existed between the railway and the telegraph, it has been difficult for the telephone, which came much later, to enter the field. =Rapid Growth.= The telephone has been in general use among the railroads for many years, but only on a few short lines has it been used for dispatching trains. In these cases the ordinary magneto circuit and instruments have been employed, differing in no respect from those used in commercial service at the present time. Code ringing was used and the number of stations on a circuit was limited by the same causes that limit the telephones on commercial party lines at present. The present type of telephone dispatching systems, however, differs essentially from the systems used in commercial work, and is, in fact, a highly specialized party-line system, arranged for selective ringing and _many stations_. The first of the present type was installed by the New York Central and Hudson River Railroad in October, 1907, between Albany and Fonda, New York, a distance of 40 miles. This section of the road is on the main line and has four tracks controlled by block signals. The Chicago, Burlington, and Quincy Railroad was the second to install train-dispatching circuits. In December, 1907, a portion of the main line from Aurora to Mendota, Illinois, a distance of 46 miles, was equipped. This was followed in quick succession by various other circuits ranging, in general, in lengths over 100 miles. At the present time there are over 20 train-dispatching circuits on the Chicago, Burlington, and Quincy Railroad covering 125 miles of double track, 28 miles of multi-track, and 1,381 miles of single track, and connecting with 286 stations. Other railroads entered this field in quick order after the initial installations, and at the present time nearly every large railroad system in the United States is equipped with several telephone train-dispatching circuits and all of these seem to be extending their systems. In 1910, several railroads, including the Delaware, Lackawanna, and Western, had their total mileage equipped with telephone dispatching circuits. The Atchison, Topeka, and Santa Fe Railroad is equipping its whole system as rapidly as possible and already is the largest user of this equipment in this country. From latest information, over 55 railroads have entered this field, with the result that the telephone is now in use in railroad service on over 29,000 miles of line. =Causes of Its Introduction.= The reasons leading to the introduction of the telephone into the dispatching field were of this nature: First, and most important, was the enactment of State and Federal Laws limiting to nine hours the working day of railroad employes transmitting or receiving orders pertaining to the movement of trains. The second, which is directly dependent upon the first, was the inability of the railroads to obtain the additional number of telegraph operators which were required under the provisions of the new laws. It was estimated that 15,000 additional operators would be required to maintain service in the same fashion after the new laws went into effect in 1907. The increased annual expense occasioned by the employment of these additional operators was roughly estimated at $10,000,000. A third reason is found in the decreased efficiency of the average railway and commercial telegraph operator. There is a very general complaint among the railroads today regarding this particular point, and many of them welcome the telephone, because, if for no other reason, it renders them independent of the telegrapher. What has occasioned this decrease in efficiency it is not easy to say, but there is a strong tendency to lay it, in part, to the attitude of the telegraphers' organization toward the student operator. It is a fact, too, that the limits which these organizations have placed on student operators were directly responsible for the lack of available men when they were needed. =Advantages.= In making this radical change, railroad officials were most cautious, and yet we know of no case where the introduction of the telephone has been followed by its abandonment, the tendency having been in all cases toward further installations and more equipment of the modern type. The reasons for this are clear, for where the telephone is used it does not require a highly specialized man as station operator and consequently a much broader field is open to the railroads from which to draw operators. This, we think, is the most far-reaching advantage. The telephone method also is faster. On an ordinary train-dispatching circuit it now requires from 0.1 of a second to 5 seconds to call any station. In case a plurality of calls is desired, the dispatcher calls one station after another, getting the answer from one while the next is being called, and so on. By speaking into a telephone many more words may be transmitted in a given time than by Morse telegraphy. It is possible to send fifty words a minute by Morse, but such speed is exceptional. Less than half that is the rule. The gain in high speed, therefore, which is obtained is obvious and it has been found that this is a most important feature on busy divisions. It is true that in the issuance of "orders," the speed, in telephonic train dispatching, is limited to that required to write the words in longhand. But all directions of a collateral character, the receipt of important information, and the instantaneous descriptions of emergency situations can be given and received at a speed limited only by that of human speech. The dispatcher is also brought into a closer personal relation with the station men and trainmen, and this feature of direct personal communication has been found to be of importance in bringing about a higher degree of co-operation and better discipline in the service. Telephone dispatching has features peculiar to itself which are important in improving the class of service. One of these is the "answer-back" automatically given to the dispatcher by the waystation bell. This informs the dispatcher whether or not the bell at the station rang, and excuses by the operators that it did not, are eliminated. Anyone can answer a telephone call in an emergency. The station operator is frequently agent also, and his duties often take him out of hearing of the telegraph sounder. The selector bell used with the telephone can be heard for a distance of several hundred feet. In addition, it is quite likely that anyone in the neighborhood would recognize that the station was wanted and either notify the operator or answer the call. In cases of emergency the train crews can get into direct communication with the dispatcher immediately, by means of portable telephone sets which are carried on the trains. It is a well-known fact that every minute a main line is blocked by a wreck can be reckoned as great loss to the railroad. It is also possible to install siding telephone sets located either in booths or on poles along the right-of-way. These are in general service today at sidings, crossings, drawbridges, water tanks, and such places, where it may be essential for a train crew to reach the nearest waystation to give or receive information. The advantage of these siding sets is coming more and more to be realized. With the telegraph method of dispatching, a train is ordered to pass another train at a certain siding, let us say. It reaches this point, and to use a railroad expression, "goes into the hole." Now, if anything happens to the second train whereby it is delayed, the first train remains tied up at that siding without the possibility of either reaching the dispatcher or being reached by him. With the telephone station at the siding, which requires no operator, this is avoided. If a train finds itself waiting too long, the conductor goes to the siding telephone and talks to the dispatcher, possibly getting orders which will advance him many miles that would otherwise have been lost. It is no longer necessary for a waystation operator to call the dispatcher. When one of these operators wishes to talk to the dispatcher, he merely takes his telephone receiver off the hook, presses a button, and speaks to the dispatcher. With the telephone it is a simple matter to arrange for provision so that the chief dispatcher, the superintendent, or any other official may listen in at will upon a train circuit to observe the character of the service. The fact that this can be done and that the operators know it can be done has a very strong tendency to improve the discipline. The dispatchers are so relieved, by the elimination of the strain of continuous telegraphing, and can handle their work so much more quickly with the telephone, that in many cases it has been found possible to increase the length of their divisions from 30 to 50 per cent. =Railroad Conditions.= One of the main reasons that delayed the telephone for so many years in its entrance to the dispatching field is that the conditions in this field are like nothing which has yet been met with in commercial telephony. There was no system developed for meeting them, although the elements were at hand. A railroad is divided up into a number of divisions or dispatchers' districts of varying lengths. These lengths are dependent on the density of the traffic over the division. In some cases a dispatcher will handle not more than 25 miles of line. In other cases this district may be 300 miles long. Over the length of one of these divisions the telephone circuit extends, and this circuit may have upon it 5 or 50 stations, _all of which may be required to listen upon the line at the same time_. It will be seen from this that the telephone dispatching circuit partakes somewhat of the nature of a long-distance commercial circuit in its length, and it also resembles a rural line in that it has a large number of telephones upon it. Regarding three other characteristics, namely, that many of these stations may be required to be in on the circuit simultaneously, that they must all be signaled selectively, and that it must also be possible to talk and signal on the circuit simultaneously, a telephone train-dispatching circuit resembles nothing in the commercial field. These requirements are the ones which have necessitated the development of special equipment. =Transmitting Orders.= The method of giving orders is the same as that followed with the telegraph, with one important exception. When the dispatcher transmits a train order by telephone, he writes out the order as he speaks it into his transmitter. In this way the speed at which the order is given is regulated so that everyone receiving it can easily get it all down, and a copy of the transmitted order is retained by the dispatcher. All figures and proper names are spelled out. Then after an order has been given, it is repeated to the dispatcher by each man receiving it, and he underlines each word as it comes in. This is now done so rapidly that a man can repeat an order more quickly than the dispatcher can underline. The doubt as to the accuracy with which it is possible to transmit information by telephone has been dispelled by this method of procedure, and the safety of telephone dispatching has been fully established. =Apparatus.= The apparatus which is employed at waystations may be divided into two groups--the selector equipment and the telephone equipment. The selector is an electro-mechanical device for ringing a bell at a waystation when the dispatcher operates a key corresponding to that station. At first, as in telegraphy, the selector magnets were connected in series in the line, but today all systems bridge the selectors across the telephone circuit in the same way and for the same reasons that it is done in bridging party-line work. There are at the present time three types of selectors in general use, and the mileage operated by means of these is probably considerably over 95 per cent of the total mileage so operated in the country. [Illustration: Fig. 475. Western Electric Selector] [Illustration: Fig. 476. Western Electric Selector] _The Western Electric Selector._ This selector is the latest and perhaps the simplest. Fig. 475 shows it with its glass dust-proof cover on, and Fig. 476 shows it with the cover removed. This selector is adapted for operating at high speed, stations being called at the rate of ten per second. The operating mechanism, which is mounted on the front of the selector so as to be readily accessible, works on the central-energy principle--the battery for its operation, as well as for the operation of the bell used in connection with it, both being located at the dispatcher's office. The bell battery may, however, be placed at the waystation if this is desired. The selector consists of two electromagnets which are bridged in series across the telephone circuit and are of very high impedance. It is possible to place as many of these selectors as may be desired across a circuit without seriously affecting the telephonic transmission. Direct-current impulses sent out by the dispatcher operate these magnets, one of which is slow and the other quick-acting. The first impulse sent out is a long impulse and pulls up both armatures, thereby causing the pawls above and below the small ratchet wheel, shown in Fig. 476, to engage with this wheel. The remaining impulses operate the quick-acting magnet and step the wheel around the proper number of teeth, but do not affect the slow-acting magnet which remains held up by them. The pawl connected to the slow-acting magnet merely serves to prevent the ratchet wheel from turning back. Attached to the ratchet wheel is a contact whose position can be varied in relation to the stationary contact on the left of the selector with which this engages. This contact is set so that when the wheel has been rotated the desired number of teeth, the two contacts will make and the bell be rung. Any selector may thus be adjusted for any station, and the selectors are thus interchangeable. When the current is removed from the line at the dispatcher's office, the armatures fall back and everything is restored to normal. An "answer-back" signal is provided with this selector dependent upon the operation of the bell. When the selector at a station operates, the bell normally rings for a few seconds. The dispatcher, however, can hold this ring for any length of time desired. The keys employed at the dispatcher's office for operating selectors are shown in Fig. 477. There is one key for each waystation on the line and the dispatcher calls any station by merely giving the corresponding key a quarter turn to the right. Fig. 478 shows the mechanism of one of these keys and the means employed for sending out current impulses over the circuit. The key is adjustable and may be arranged for any station desired by means of the movable cams shown on the rear in Fig. 478, these cams, when occupying different positions, serving to cover different numbers of the teeth of the impulse wheel which operate the impulse contacts. [Illustration: Fig. 477. Dispatcher's Keys] [Illustration: Fig. 478. Dispatcher's Key Mechanism] _The Gill Selector._ The second type of selector in extensive use throughout the country today is known as the Gill, after its inventor. It is manufactured for both local-battery and central-energy types, the latter being the latest development of this selector. With the local-battery type, the waystation bell rings until stopped by the dispatcher. With the central-energy type it rings a definite length of time and can be held for a longer period as is the case with the Western Electric selector. The selector is operated by combinations of direct-current impulses which are sent out over the line by keys in the dispatcher's office. [Illustration: Fig. 479. Gill Selector] The dispatcher has a key cabinet, and calls in the same way as already described, but these keys instead of sending a series of quick impulses, send a succession of impulses with intervals between corresponding to the particular arrangement of teeth in the corresponding waystation selector wheel. Each key, therefore, belongs definitely with a certain selector and can be used in connection with no other. A concrete example may make this clearer. The dispatcher may operate key No. 1421. This key starts a clockwork mechanism which impresses at regular intervals, on the telephone line, direct-current impulses, with intervals between as follows: 1-4-2-1. There is on the line one selector corresponding to this combination and it alone, of all the selectors on the circuit, will step its wheel clear around so that contact is made and the bell is rung. In all the others, the pawls will have slipped out at some point of the revolution and the wheels will have returned to their normal positions. The Gill selector is shown in Fig. 479. It contains a double-wound relay which is bridged across the telephone circuit and operates the selector. This relay has a resistance of 4,500 ohms and a high impedance, and operates the selector mechanism which is a special modification of the ratchet and pawl principle. The essential features of this selector are the "step-up" selector wheel and a time wheel, normally held at the bottom of an inclined track. The operation of the selector magnet pushes the time wheel up the track and allows it to roll down. If the magnet is operated rapidly, the wheel does not get clear down before being pushed back again. A small pin on the side of the pawl, engaging the selector wheel normally, opposes the selector wheel teeth near their outer points. When the time wheel rolls to the bottom of the track, however, the pawl is allowed to drop to the bottom of the tooth. Some of the teeth on the selector wheel are formed so that they will effectually engage with the pawl only when the latter is in normal position, while others will engage only while the pawl is at the bottom position; thus innumerable combinations can be made which will respond to certain combinations of rapid impulses with intervals between. The correct combination of impulses and intervals steps the selector wheel clear around so that a contact is made. The selector wheels at all other stations fail to reach their contact position because at some point or points in their revolution the pawls have slipped out, allowing the selector wheels to return "home." The "answer-back" is provided in this selector by means of a few inductive turns of the bell circuit which are wound on the selector relay. The operation of the bell through these turns induces an alternating current in the selector winding which flows out on the line and is heard as a distinctive buzzing noise by the dispatcher. [Illustration: Fig. 480. Cummings-Wray Dispatcher's Sender] _The Cummings-Wray Selector._ Both of the selectors already described are of a type known as the _individual-call_ selectors, meaning that only one station at a time can be called. If a plurality of calls is desired, the dispatcher calls one station after another. The third type of selector in use today is of a type known as the _multiple-call_, in which the dispatcher can call simultaneously as many stations as he desires. The Cummings-Wray selector and that of the Kellogg Switchboard and Supply Company are of this type and operate on the principle of synchronous clocks. When the dispatcher wishes to put through a call, he throws the keys of all the stations that he desires and then operates a starting key. The bells at all these stations are rung by one operation. The dispatcher's sending equipment of the Cummings-Wray system is shown in Fig. 480, and the waystation selector in Fig. 481. It is necessary with this system for the clocks at all stations to be wound every eight days. [Illustration: Fig. 481. Cummings-Wray Selector] In the dispatcher's master sender the clock-work mechanism operates a contact arm which shows on the face of the sender in Fig. 480. There is one contact for every station on the line. The clock at this office and the clocks at all the waystation offices start together, and it is by this means that the stations are signaled, as will be described later, when the detailed operation of the circuits is taken up. =Telephone Equipment.= Of no less importance than the selective devices is the telephone apparatus. That which is here illustrated is the product of the Western Electric Company, to whom we are indebted for all the illustrations in this chapter. _Dispatcher's Transmitter._ The dispatcher, in most cases, uses the chest transmitter similar to that employed by switchboard operators in every-day service. He is connected at all times to the telephone circuit, and for this reason equipment easy for him to wear is essential. In very noisy locations he is equipped with a double head receiver. On account of the dispatcher being connected across the line permanently and of his being required to talk a large part of the time, there is a severe drain on the transmitter battery. For this reason storage batteries are generally used. [Illustration: Fig. 482. Waystation Desk Telephone] _Waystation Telephones._ At the waystations various types of telephone equipment may be used. Perhaps the most common is the familiar desk stand shown in Fig. 482, which, for railroad service, is arranged with a special hook-switch lever for use with a head receiver. Often some of the familiar swinging-arm telephone supports are used, in connection with head receivers, but certain special types developed particularly for railway use are advantageous, because in many cases the operator who handles train orders is located in a tower where he must also attend to the interlocking signals, and for such service it is necessary for him to be able to get away from the telephone and back to it quickly. The Western Electric telephone arm developed for this use is shown in Fig. 483. In this the transmitter and the receiver are so disposed as to conform approximately to the shape of the operator's head. When the arm is thrown back out of the way it opens the transmitter circuit by means of a commutator in its base. [Illustration: Fig. 483. Telephone Arm] _Siding Telephones._ Two types of sets are employed for siding purposes. The first is an ordinary magneto wall instrument, which embodies the special apparatus and circuit features employed in the standard waystation sets. These are used only where it is possible to locate them indoors or in booths along the line. These sets are permanently connected to the train wire, and since the chances are small that more than one of them will be in use at a time, they are rung by the dispatcher, by means of a regular hand generator, when it is necessary for him to signal a switching. [Illustration: Fig. 484. Weather-Proof Telephone Set] In certain cases it is not feasible to locate these siding telephone sets indoors, and to meet these conditions an iron weather-proof set is employed, as shown in Figs. 484 and 485. The apparatus in this set is treated with a moisture-proofing compound, and the casing itself is impervious to weather conditions. [Illustration: Fig. 485. Weather-Proof Telephone Set] _Portable Train Sets._ Portable telephone sets are being carried regularly on wrecking trains and their use is coming into more and more general acceptance on freight and passenger trains. Fig. 486 shows one of these sets equipped with a five-bar generator for calling the dispatcher. Fig. 487 shows a small set without generator for conductors' and inspectors' use on lines where the dispatcher is at all times connected in the circuit. [Illustration: Fig. 486. Portable Telephone Set] [Illustration: Fig. 487. Portable Telephone Set] These sets are connected to the telephone circuit at any point on the line by means of a light portable pole arranged with terminals at its outer extremity for hooking over the line wires, and with flexible conducting cords leading to the portable set. The use of these sets among officials on their private cars, among construction and bridge gangs working on the line, and among telephone inspectors and repairmen for reporting trouble, is becoming more and more general. =Western Electric Circuits.= As already stated, a telephone train-dispatching circuit may be from 25 to 300 miles in length, and upon this may be as many stations as can be handled by one dispatcher. The largest known number of stations upon an existing circuit of this character is 65. [Illustration: Fig. 488. Dispatcher's Station--Western Electric System] _Dispatcher's Circuit Arrangement._ The circuits of the dispatcher's station in the Western Electric system are shown in Fig. 488, the operation of which is briefly as follows: When the dispatcher wishes to call any particular station, he gives the key corresponding to that station a quarter turn. This sends out a series of rapid direct-current impulses on the telephone line through the contact of a special telegraph relay which is operated by the key in a local circuit. The telegraph relay is equipped with spark-eliminating condensers around its contacts and is of heavy construction throughout in order to carry properly the sending current. _Voltage._ The voltage of the sending battery is dependent on the length of the line and the number of stations upon it. It ranges from 100 to 300 volts in most cases. When higher voltages are required in order successfully to operate the circuit, it is generally customary to install a telegraph repeater circuit at the center of the line, in order to keep the voltage within safe limits. One reason for limiting the voltage employed is that the condensers used in the circuit will not stand much higher potentials without danger of burning out. It is also possible to halve the voltage by placing the dispatcher in the center of the line, from which position he may signal in two directions instead of from one end. _Simultaneous Talking and Signaling._ Retardation coils and condensers will be noticed in series with the circuit through which the signaling current must pass before going out on the line. These are for the purpose of absorbing the noise which is caused by high-voltage battery, thus enabling the dispatcher to talk and signal simultaneously. The 250-ohm resistance connected across the circuit through one back contact of the telegraph relay absorbs the discharge of the 6-microfarad condenser. [Illustration: Fig. 489. Selector Set--Western Electric System] =Waystation Circuit.= The complete selector set for the waystations is shown in Fig. 489, and the wiring diagram of its apparatus in Fig. 490. The first impulse sent out by the key in the dispatcher's office is a long direct-current impulse, the first tooth being three or four times as wide as the other teeth. This impulse operates both magnets of the selector and attracts their armatures, which, in turn, cause two pawls to engage with the ratchet wheel, while the remaining quick impulses operate the "stepping-up" pawl and rotate the wheel the requisite number of teeth. Retardation coils are placed in series with the selector in order to choke back any lightning discharges which might come in over the line. The selector contact, when operated, closes a bell circuit, and it will be noted that both the selector and the bell are operated from battery current coming over the main line through variable resistances. There are, of course, a number of selectors bridged across the circuit, and the variable resistance at each station is so adjusted as to give each approximately 10 milliamperes, which allows a large factor of safety for line leakage in wet weather. The drop across the coils at 10 milliamperes is 38 volts. If these coils were not employed, it is clear that the selectors nearer the dispatcher would get most of the current and those further away very little. [Illustration: Fig. 490. Selector Set--Western Electric System] A time-signal contact is also indicated on the selector-circuit diagram of Fig. 490. This is common to all offices and may be operated by a special key in the dispatcher's office, thereby enabling him to send out time signals over the telephone circuit. [Illustration: Fig. 491. Gill Dispatcher's Station] =Gill Circuits.= The circuit arrangement for the dispatcher's outfit of the Gill system is shown in Fig. 491. This is similar to that of the Western Electric system just described. The method of operation also is similar, the mechanical means of accomplishing the selection being the main point of difference. In Fig. 492 the wiring of the Gill selector at a waystation for local-battery service is shown. The selector contact closes the bell circuit in the station and a few windings of this circuit are located on the selector magnets, as shown. These provide the "answer-back" by inductive means. [Illustration: Fig. 492. Gill Selector--Local Battery] Fig. 493 shows the wiring of the waystation, central-energy Gill selector. In this case, the local battery for the operation of the bell is omitted and the bell is rung, as is the case of the Western Electric selector, by the main sending battery in the dispatcher's office. [Illustration: Fig. 493. Gill Selector--Central Energy] The sending keys of these two types of circuits differ, in that with the local-battery selector the key contact is open after the selector has operated, and the ringing of the bell must be stopped by the dispatcher pressing a button or calling another station. Either of these operations sends out a new current impulse which releases the selector and opens its circuit. With the central-energy selector, however, the contacts of the sending key at the dispatcher's office remain closed after operation for a definite length of time. This is obviously necessary in order that battery may be kept on the line for the operation of the bell. In this case the contacts remain closed during a certain portion of the revolution of the key, and the bell stops ringing when that portion of the revolution is completed. If, however, the dispatcher desires to give any station a longer ring, he may do so by keeping the key contacts closed through an auxiliary strap key as soon as he hears the "answer-back" signal from the called station. =Cummings-Wray Circuits.= The Cummings-Wray system, as previously stated, is of the multiple-call type, operating with synchronous clocks. Instead of operating one key after another in order to call a number of stations, all the keys are operated at once and a starting key sets the mechanism in motion which calls all these stations with one operation. Fig. 494 shows the circuit arrangement of this system. [Illustration: Fig. 494. Cummings-Wray System] In order to ring one or more stations, the dispatcher presses the corresponding key or keys and then operates the starting key. This starting key maintains its contact for an appreciable length of time to allow the clock mechanism to get under way and get clear of the releasing magnet clutch. Closing the starting key operates the clock-releasing magnet and also operates the two telegraph-line relays. These send out an impulse of battery on the line operating the bridged 2,500-ohm line relays and, in turn, the selector releasing magnets; thus, all the waystation clocks start in unison with the master clock. The second hand arbor of each clock carries an arm, which at each waystation is set at a different angle with the normal position than that at any other station. Each of these arms makes contact precisely at the moment the master-clock arm is passing over the contact corresponding to that station. If, now, a given station key is pressed in the master sender, the telegraph-line relays will again operate when the master-clock arm reaches that point, sending out another impulse of battery over the line. The selector contact at the waystation is closed at this moment; therefore, the closing of the relay contact operates the ringing relay through a local circuit, as shown. The ringing relay is immediately locked through its own contact, thus maintaining the bell circuit closed until it is opened by the key and the ringing is stopped. As the master-clock arm passes the last point on the contact dial, the current flows through the restoring relay operating the restoring magnet which releases all the keys. A push button is provided by means of which the keys may be manually released, if desired. This is used in case the dispatcher presses a key by mistake. Retardation coils and variable resistances are provided at the waystation just as with the other selector systems which have been described and for the same reasons. The circuits of the operator's telephone equipment shown in Fig. 495, are also bridged across the line. This apparatus is of high impedance and of a special design adapted to railroad service. There may be any number of telephones listening in upon a railroad train wire at the same time, and often a dispatcher calls in five or six at once to give orders. These conditions have necessitated the special circuit arrangement shown in Fig. 495. [Illustration: Fig. 495. Telephone Circuits] The receivers used at the waystations are of high impedance and are normally connected, through the hook switch, directly across the line in series with a condenser. When the operator, at a waystation wishes to talk, however, he presses the key shown. This puts the receiver across the line in series with the retardation coil and in parallel with the secondary of the induction coil. It closes the transmitter battery circuit at the same time through the primary of the induction coil. The retardation coil is for the purpose of preventing excessive side tone, and it also increases the impedance of the receiver circuit, which is a shunt on the induction coil. This latter coil, however, is of a special design which permits just enough current to flow through the receiver to allow the dispatcher to interrupt a waystation operator when he is talking. The key used to close the transmitter battery is operated by hand and is of a non-locking type. In some cases, where the operators are very busy, a foot switch is used in place of this key. The use of such a key or switch in practical operation has been found perfectly satisfactory, and it takes the operators but a short time to become used to it. The circuits of the dispatcher's office are similarly arranged, Fig. 495, being designed especially to facilitate their operation. In other words, as the dispatcher is doing most of the work on the circuit, his receiver is of a low-impedance type, which gives him slightly better transmission than the waystations obtain. The key in his transmitter circuit is of the locking type, so that he does not have to hold it in while talking. This is for the reason that the dispatcher does most of the talking on this circuit. Foot switches are also employed in some cases by the dispatchers. =Test Boards.= It is becoming quite a general practice among the railroads to install more than one telephone circuit along their rights-of-way. In many cases in addition to the train wire, a message circuit is also equipped, and quite frequently a block wire also operated by telephone, parallels these two. It is desirable on these circuits to be able to make simple tests and also to be able to patch one circuit with another in cases of emergency. [Illustration: Fig. 496. Test Board] Test boards have been designed for facilitating this work. These consist of simple plug and jack boxes, the general appearance of which is shown in Fig. 496. The circuit arrangement of one of these is shown in Fig. 497. Each wire comes into an individual jack as will be noted on one side of the board, and passes through the inside contact of this jack, out through a similar jack on the opposite side. The selector and telephone set at an office are taken off these inside contacts through a key, as shown. The outside contacts of this key are wired across two pairs of cords. Now, assume the train wire comes in on jacks _1_ and _3_, and the message wire on jacks _9_ and _11_. In case of an accident to the train wire between two stations, it is desirable to patch this connection with a message wire in order to keep the all-important train wire working. The dispatcher instructs the operator at the last station which he can obtain, to insert plugs _1_ and _2_ in jacks _1_ and _10_, and plugs _3_ and _4_ in jacks _3_ and _12_, at the same time throwing the left-hand key. Then, obtaining an operator beyond the break by any available means, he instructs him likewise to insert plugs _1_ and _2_ in jacks _9_ and _2_, and plugs _3_ and _4_ in jacks _11_ and _4_, similarly throwing the left-hand key. By tracing this out, it will be observed that the train wire is patched over the disabled section by means of the message circuit, and that the selector and the telephone equipment are cut over on to the patched connections; in other words, bridged across the patching cords. [Illustration: Fig. 497. Circuits of Test Board] It will also be seen that with this board it is possible to open any circuit merely by plugging into a jack. Two wires can be short-circuited or a loop made by plugging two cords of corresponding colors into the two jacks. A ground jack is provided for grounding any wire. In this way, a very flexible arrangement of circuits is obtained, and it is possible to make any of the simple tests which are all that are usually required on this type of circuit. =Blocking Sets.= As was just mentioned, quite frequently in addition to train wires and message circuits, block wires are also operated by telephone. In some cases separate telephone instruments are used for the blocking service, but in others the same man handles all three circuits over the same telephone. The block wire is generally a converted telegraph wire between stations, usually of iron and usually grounded. It seldom ranges in length over six miles. [Illustration: Fig. 498. Blocking Set] Where the block wires are operated as individual units with their own instruments, it is unnecessary to have any auxiliary apparatus to be used in connection with them. Where, however, they are operated as part of a system and the same telephone is used on these that is used on the train wire and message wire, additional apparatus, called a blocking set, is required. This blocking set, shown in Figs. 498 and 499, was developed especially for this service by the Western Electric Company. As will be noted, a repeating coil at the top and a key on the front of the set are wired in connection with a pair of train wire cords. This repeating coil is for use in connecting a grounded circuit to a metallic circuit, as, for instance, connecting a block wire to the train wire, and is, of course, for the purpose of eliminating noise. Below the key are three combined jacks and signals. One block wire comes into each of these and a private line may be brought into the middle one. When the next block rings up, a visual signal is displayed which operates a bell in the office by means of a local circuit. The operator answers by plugging the telephone cord extending from the bottom of the set into the proper jack. This automatically restores the signal and stops the bell. [Illustration: Fig. 499. Blocking Set] Below these signals appear four jacks. One is wired across the train wire; one across the message wire; and the other two are bridged across the two pairs of patching cords on each side of the set. The operator answers a call on any circuit by plugging his telephone cord into the proper jack. If a waystation is not kept open in the evening, or the operator leaves it for any reason and locks up, he can connect two blocks together by means of the block-wire cords. These are arranged simply for connecting two grounded circuits together and serve to join two adjacent blocks, thereby eliminating one station. A jack is wired across these cords, so that the waystation operator can listen in on the connection if he so desires. In some cases not only are the telephone circuits brought into the test board, but also two telegraph wires are looped through this board before going to the peg switchboard. This is becoming quite a frequent practice and, in times of great emergency, enables patches to be made to the telegraph wires as well as to the telephone wires. =Dispatching on Electric Railways.= As interurban electric railways are becoming more extended, and as their traffic is becoming heavier, they approximate more closely to steam methods of operation. It is not unusual for an electric railway to dispatch its cars exactly as in the case of a steam road. There is a tendency, however, in this class of work, toward slightly different methods, and these will be briefly outlined. On those electric railways where the traffic is not especially heavy, an ordinary magneto telephone line is frequently employed with standard magneto instruments. In some cases the telephone sets are placed in waiting rooms or booths along the line of the road. In other cases it is not feasible to locate the telephone indoors and then iron weather-proof sets, such as are shown in Figs. 484 and 485, are mounted directly on the poles along the line of railway. With a line of this character there is usually some central point from which orders are issued and the trainmen call this number when arriving at sidings or wherever they may need to do so. Another method of installing a telephone system upon electric railways is as follows: Instead of instruments being mounted in booths or on poles along the line, portable telephone sets are carried on the cars and jacks are located at regular intervals along the right-of-way on the poles. The crew of the car wishing to get in touch with the central office or the dispatcher, plugs into one of these jacks and uses the portable telephone set. At indoor stations, in offices or buildings belonging to the railroad, the regular magneto sets may be employed, as in the first case outlined. On electric railway systems where the traffic is heavy, the train or car movements may be handled by a dispatcher just as on the steam railroad. There is usually one difference, however. On a steam road, the operators who give the train crews their orders and manipulate the semaphore signals are located at regular intervals in the different waystations. No such operators are usually found on electric railways, except, perhaps, at very important points, and, therefore, it is necessary for the dispatcher to be able to signal cars at any point and to get into communication with the crews of these cars. He does this by means of semaphores operated by telephone selectors over the telephone line. The telephone circuit may be equipped with any number of selectors desired, and the dispatcher can operate any particular one without operating any other one on the circuit. Each selector, when operated, closes a pair of contacts. This completes a local circuit which throws the semaphore arm to the "danger" position, at the same time giving the dispatcher a distinctive buzz in his ear, which informs him that the arm has actually moved to this position. He can get this signal only by the operation of the arm. Each semaphore is located adjacent to a telephone booth in which is also placed the restoring lever, by means of which the semaphore is set in the "clear" position by the crew of the car which has been signaled. The wall-type telephone set is usually employed for this class of service, but if desired, desk stands or any of the various transmitter arms may be used. It is necessary for the crew of the car which first approaches a semaphore set at "danger," to get out, communicate with the dispatcher, and restore the signal to the "clear" position. The dispatcher can not restore the signal. The signal is set only in order that the train crew may get into telephonic communication with the dispatcher, and in order to do this, it is necessary for them to go into the booth in any case. [Footnote A: We wish particularly to acknowledge the courtesy of the Western Electric Company in their generous assistance in the preparation of this chapter.] REVIEW QUESTIONS REVIEW QUESTIONS ON THE SUBJECT OF TELEPHONY PAGES 11--68 * * * * * 1. What are the advantages of a common-battery system? 2. When is the local battery to be preferred to the common-battery? 3. Enumerate the different kinds of line signals. 4. Make a diagram of the arrangement of a direct line lamp signal. 5. What is a direct line lamp with ballast? Give sketch. 6. Describe a line lamp with relay. 7. What is a pilot lamp and what are its functions? 8. Sketch three different kinds of batteries applied to cord circuits. 9. What is a supervisory signal? 10. Make diagram of a complete simple common-battery switchboard circuit. 11. When will the supervisory signal become operative? 12. What is the candle-power of incandescent lamps used for line and supervisory signals? 13. At what voltages do they operate? 14. What are visual signals? 15. Describe the mechanical signal of the Western Electric Company. 16. Give a short description of the general assembly of the parts of a simple common-battery switchboard. 17. What is a transfer switchboard? 18. Outline the limitations of a simple switchboard. 19. Describe and sketch a plug-ended transfer line. 20. Why is the plug-seat switch not more widely adopted for use? 21. Make diagram of an order-wire arrangement. 22. What are the limitations of the transfer system? 23. What are the fundamental features of the multiple switchboard? 24. What is a multiple jack? 25. What is an answering jack? 26. Make a diagram showing the principle of multiple switchboards. 27. What is the busy signal? 28. What determines the size of a multiple switchboard? 29. What is the use of the intermediate distributing frame? 30. Make diagram of the series magneto multiple switchboard and describe its operation. 31. What are the defects of this system? 32. Give a diagram of the branch terminal magneto multiple switchboard. 33. Give a diagram and a short description of the Monarch magneto multiple switchboard. REVIEW QUESTIONS ON THE SUBJECT OF TELEPHONY PAGES 69--134 * * * * * 1. Sketch and describe the line circuit of the common-battery multiple switchboard of the Bell companies. 2. Make a diagram of the cord circuit of the Western Electric standard multiple common-battery switchboard. 3. Describe the busy test in this system. 4. What is the function of the order-wire circuits? 5. What is jumper wire? 6. Give a short description of the relay mounting in the standard No. 1 relay board of the Western Electric Company. 7. What is the ultimate capacity of the No. 1 Western Electric switchboard? 8. What is the capacity of the No. 10 Western Electric switchboard? 9. How does this switchboard No. 10 differ from No. 1? 10. Give a diagram of the two-wire line circuit of the Kellogg Company. 11. What is the capacity of the condenser of the cord circuit in the foregoing system? 12. Give a complete diagram of the Kellogg two-wire board. 13. Describe the busy test in this system. 14. Give diagram of the Stromberg-Carlson multiple-board circuit. 15. What is the most important piece of apparatus in a multiple switchboard? 16. What is the spacing of the multiple jacks in the No. 1 Western Electric switchboard? 17. How do the relays of the Western Electric Company differ from those of other companies? 18. Describe the relay construction of the Monarch Telephone Company. 19. What is meant by inter-office trunking? 20. What is the present practice in America as to the capacity of multiple hoards? 21. What is the tendency in Europe regarding the capacity of multiple boards? 22. Discuss the preferences in American practice. 23. State the different methods of trunking between exchanges. 24. When are two-way trunks employed? 25. Make diagram of the Western Electric inter-office connection system. 26. Describe the standard four-party line trunk ringing key of the Western Electric Company. 27. Sketch and describe a keyless trunk. 28. Give diagram of the inter-office connection of the Kellogg system. 29. How does this system differ from the Western Electric in regard to the ringing? 30. Why are the A and B switchboards in large exchanges entirely separated? REVIEW QUESTIONS ON THE SUBJECT OF TELEPHONY PAGES 135--226 * * * * * 1. What is the general object of automatic telephone systems? 2. What are the common arguments against these systems and how are they met? 3. Give the operations that the calling subscriber has to go through in any one of the successful systems. 4. During calling what is happening at the central office? 5. Describe the action of the Strowger or Automatic Electric Company selecting switch. 6. What is the function of a line switch? 7. Describe the Strowger scheme of trunking and illustrate its action by diagram. 8. Make a diagram of the sub-station apparatus and connections. 9. Make a diagram of the line switch unit. 10. Describe the action of the various guarding features necessary to protect a busy line. 11. Make a simple diagram of the circuits of the first selector. 12. Give the functions and operations of the connector. 13. Give a diagram of connecting circuits. 14. Tell all you can regarding the battery supply to the connected subscriber. 15. How are subscribers disconnected after they are through talking? 16. Describe a multi-office system. 17. Give a diagram of circuits of the trunk repeater. 18. Make a complete diagram of the connections between a calling and a called subscriber in an automatic system. 19. What is the rotary connector? 20. Describe the sub-station equipment of the Lorimer automatic system. 21. Describe the Lorimer central-office apparatus. 22. Give a description of the progress of a call from its institution to the final disconnection in the Lorimer system. 23. What is the automanual system? 24. Give general features of the operation in the automanual system. 25. Describe the automanual system subscribers' apparatus. 26. Give a description of the automanual central-office equipment. REVIEW QUESTIONS ON SUBJECT OF TELEPHONY PAGES 227--270 * * * * * 1. What kinds of currents are employed? 2. What types of power plants are used? 3. Describe the sources of current supplied for the operator's transmitter current and ringing current. 4. Make a diagram of the Warner pole changer. 5. Make a diagram of pole changers for harmonic ringing. 6. What is a multi-cyclic generator set? 7. Make a diagram of governor for harmonic ringing generators. 8. Describe the various primary sources of power. 9. Make a diagram of the mercury-arc-rectifier circuits. 10. What provision against breakdown is made? 11. Tell all you can about the storage battery--its construction and its operation. 12. What is a pilot cell? 13. Describe the switches, meters, and protective devices used on the power switchboard. 14. Give a diagram showing a typical example of a common-battery manual switchboard equipment and circuits. 15. Give the main points concerning the construction of a central-office building. 16. What provision should be made for cable runways? 17. Make a sketch of a small central-office floor plan. 18. Describe the Western Electric main and intermediate frames. Give diagrams. 19. Give principal points regarding small office terminal apparatus. 20. Give types of line circuits. 21. Describe the typical equipment of a large manual office. Give floor plans. 22. Give floor plan of an automatic office. REVIEW QUESTIONS ON THE SUBJECT OF TELEPHONY PAGES 271--320 * * * * * 1. What is a private-branch exchange? 2. What does "P. B. X." mean? 3. What is the function of the private-branch exchange operator? 4. Describe the key type of a small private-branch exchange switchboard. 5. Describe the different methods of supervision of private-branch connections. 6. Describe the automatic equipment of the common-battery type in private-branch exchanges. 7. How is secrecy of individual lines obtained in a private-exchange equipment? 8. What is an intercommunicating system? 9. Sketch a magneto intercommunicating system. 10. Sketch and describe a plug type common-battery intercommunicating system. 11. Sketch and describe the action of the push button in the Monarch system and in the Western Electric system. 12. Sketch and describe the Monarch intercommunicating system. 13. What is the office of the junction box in this system? 14. What is a long-distance message? 15. What is the function of the repeating coil in the long-distance line? 16. Which is the simplest form of long-distance switch? 17. What is a phantom circuit? 18. Under what control is the ringing of the subscriber in long-distance calls? 19. What is meant by ticket passing? 20. What particular advantage has a common-battery set on long-distance lines? 21. Give a typical load curve for telephone traffic. 22. Why is traffic a study of importance? 23. State the function of the intermediate distributing frame. 24. State the different methods of traffic study. 25. What is the trunking factor? 26. Define _trunking efficiency_. 27. Enumerate some of the elements upon which the quality of service in a manual system depends. 28. What is team work? 29. How does the cost of telephone service vary? 30. What two general methods of charging for telephone service are in use? 31. Describe a calculagraph and how is it used? 32. How are toll connections timed by the Monarch Telephone Company? 33. Sketch and describe the Western Electric Company line circuit and service meter. REVIEW QUESTIONS ON THE SUBJECT OF TELEPHONY PAGES 321--358 * * * * * 1. Describe a phantom circuit with diagram. 2. Explain how two phantoms may be joined by a physical circuit. 3. Which are the better, phantom or physical circuits, and why? 4. Explain how the simplex circuit differs from the phantom telephone circuit. 5. Why are not telegraph wires as serviceable for telephone work as telephone wires are for telegraph work? 6. Give the names of the different parts of a railway composite set and explain method of operating. 7. State the causes of the introduction of the telephone into the train dispatching field and explain the advantages it has over the telegraph for this work. 8. In transmitting orders for train dispatching, how are mistakes avoided? 9. Describe the Western Electric selector and explain its use. 10. In what way does the Gill selector differ from the Western Electric? 11. What special feature does the multiple coil selector possess? 12. What special arrangement is provided for the train dispatcher in noisy locations? 13. How can a man on a wrecking train get connection with the train dispatcher? 14. What is the usual limit in length of a telephone train dispatching circuit and what is the largest number of stations at present existing on such a circuit? 15. What is the voltage of the sending battery for a train dispatcher's circuit and upon what is it dependent? 16. For what purpose is a repeater circuit used? 17. How is the noise caused by a high voltage battery absorbed so that the dispatcher may talk and signal simultaneously? 18. Draw a diagram showing the circuit arrangement for the dispatcher's outfit of the Gill system. 19. Explain fully the purpose of the retardation coil in connection with a waystation set. 20. In case of accident to a train wire between two stations, how can the connection be patched if the road is also equipped with a message circuit in addition to the train wire? 21. Why do some railroads have block wires in addition to train wires and message circuits? 22. If a waystation on a block wire is to be cut out for any length of time, by what method can the two adjacent blocks be connected, eliminating the station between? 23. What are some of the methods used for dispatching on electric railways where the traffic is not especially heavy? 24. On an electric road in case a car approaches a semaphore set at "danger," what must the crew of the car do? INDEX _The page numbers of this volume will be found at the bottom of the pages; the numbers at the top refer only to the section._ A Automanual system 218 automatic distribution of calls 223 automatic switching equipment 222 building up a connection 224 characteristics of 218 operation 219 operator's equipment 220 setting up a connection 224 speed in handling calls 224 subscriber's apparatus 219 Automatic desk stand 158 Automatic Electric Company's telephone system 149 automatic sub-offices 201 connector 185 function of 185 location of 186 operation of 186 first selector operation 179 function of line switch 152 line switch 153, 163 bridge cut-off 173 circuit operations 167 guarding functions 173 line and trunk contacts 164 locking segment 172 master switch 171 relation of, to connectors 174 structure of 166 summary of operation 174 trunk ratio 165 trunk selection 165 multi-office system 196 party lines 202 release after conversation 196 rotary connector 202 second selector operation 182 selecting switches 153, 175 release mechanism 178 side switch 175 subdivision of subscribers' lines 152 subscribers' station apparatus 158 operation 160 bell and transmitter springs 160 ground springs 160 impulse springs 161 release springs 163 ringing springs 163 salient points 163 trunking 154 connector action 157 first selector action 156 line switch action 154 second selector action 156 two-wire automatic systems 203 two-wire and three-wire systems 157 underlying feature of trunking system 153 Automatic telephone systems 135 arguments against 135 attitude of public 141 complexity 136 expense 140 flexibility 140 subscriber's station equipment 142 automatic vs. manual 143 comparative costs 142 definition 135 methods of operation 143 fundamental idea 147 grouping of subscribers 145 local and inter-office trunks 148 Lorimer system 144 magnet vs. power-driven switches 144 Automatic telephone systems methods of operation multiple vs. trunking 145 outline of action 146 Strowger system 143 testing 148 trunking between groups 145 Automatic wall set 158 B Blocking sets 355 Busy test 48 busy-test faults 50 potential of test thimbles 49 principle 49 C Circuits 321 applications 322 composite 326 phantom 321 transmission over 324 transpositions 323 railway composite 327 ringing 327 simplex 324 Common-battery multiple switchboard 69 assembly 106 Dean multiple board 93 cord circuit 94 line circuit 93 listening key 94 ringing keys 94 test 94 Kellogg two-wire multiple board 84 battery feed 88 busy test 90 complete cord and line circuit 88 cord circuit 86 line circuit 85 summary of operation 91 supervisory signals 87 wiring of line circuit 92 multiple switchboard apparatus 97 jacks 99 lamp jacks 100 relays 101 Stromberg-Carlson multiple board 96 cord circuit 96 supervisory signals 97 test 97 Western Electric No. 1 relay board 69 capacity range 80 cord circuit 71 functions of distributing frames 77 line circuit 69 modified relay windings 79 operation 72 operator's circuit detail 75 order-wire circuits 78 pilot signals 79 relay mounting 80 testing--called line busy 75 testing--called line idle 74 wiring of line circuit 76 Western Electric No. 10 board 80 circuits 81 economy 84 operation 83 test 83 Common-battery switchboard 11 advantages of operation 11 common battery vs. magneto 12 cord circuit 20 battery supply 20 complete circuit 21 supervisory signals 21 cycle of operations 23 jacks 30 lamps 24 mounting 25 line signals 14 direct-line lamp 14 direct-line lamp with ballast 15 line lamp with relay 17 pilot signals 17 mechanical signals 27 Kellogg 28 Monarch 28 Western Electric 27 relays 28 switchboard assembly 31 Composite circuits 326 Connector 185 Cord circuit 20 Cord circuit battery supply 20 complete circuit 21 supervisory signals 21 Cord-rack connectors 66 Cummings-Wray selector 342 D Dean multiple board 93 Dispatchers' keys 339 Dispatching on electric railways 356 G Gill selector 341 H Housing central-office equipment 249 arrangement of apparatus in small manual offices 252 combined main and intermediate frames 253 floor plans for 252 types of line circuits 255 automatic offices 267 typical automatic office 270 central-office building 249 fire hazard 249 provision for cable runways 251 provision for employes 251 size of building 250 strength of building 250 large manual office 256 I Intercommunicating systems 282 common-battery systems 283 Kellogg plug type 284 Kellogg push-button type 285 Monarch system 287 Western Electric system 285 definition 282 limitations 282 for private-branch exchanges 290 simple magneto system 282 J Jacks 30 K Kellogg mechanical signal 28 Kellogg trunk circuits 125 Kellogg two-wire multiple board 84 Keyboard wiring 67 L Lamp mounting 25 Lamps 24 Line signals 14 direct-line lamp 14 direct-line lamp with ballast 15 line lamp with relay 17 pilot signals 17 Line switch 163 Long-distance switching 293 definitions 293 center-checking 297 operators' orders 294 by call circuits 294 by telegraph 294 particular party calls 295 switching through local board 293 ticket passing 296 trunking 295 high-voltage toll trunks 295 through ringing 295 two-number calls 294 use of repeating coil 293 waystations 297 Lorimer automatic system 144, 205 central-office apparatus 208 connective division 210 sectional apparatus 209 switches 213 interconnector 214 interconnector selector 214 primary connector 213 rotary switch 213 secondary connector 214 signal transmitter controller 214 operation 215 subscriber's station equipment 206 M Magneto multiple switchboard 53 branch-terminal multiple board 58 arrangement of apparatus 61 magnet windings 61 operation 60 field of utility 53 modern magneto multiple board 63 assembly 66 cord circuit 64 test 62 Magneto multiple switchboard series-multiple board 54 defects 57 operation 56 Measured service 310 local service 316 meter method 316 prepayment method 318 ticket method 316 rates 310 toll service 311 long haul 311 short haul 311 timing toll connections 312 units of charging 311 Mechanical signals 27 Kellogg 28 Monarch 28 Western Electric 27 Mercury-arc rectifier circuits 237 Monarch visual signal 28 Multi-office exchanges, necessity for 109 Multiple switchboard 43 busy test 48 cord circuits 46 diagram showing principle of 47 double connections 46 field of each operator 51 field of utility 43 influence of traffic 52 line signals 45 multiple feature 43 P Phantom circuit 321 Pilot signals 17 Plug-seat switch 38 Pole changers for harmonic ringing 231 Power plants 227 auxiliary signaling currents 233 currents employed 227 alternating current 227 direct current 227 operator's transmitter supply 228 power plant circuit 248 power switchboard 246 meters 246 protective devices 248 switches 246 primary sources 234 charging from direct-current mains 234 charging dynamos 235 mercury-arc rectifiers 236 rotary converters 234 provision against breakdown 237 capacity of power units 238 duplicate charging machines 238 duplicate primary sources 238 duplicate ringing machines 238 ringing-current supply 229 magneto generators 229 pole changers 229 ringing dynamos 232 storage battery 239 initial charge 241 installation 240 low cells 244 operation 242 overcharge 243 pilot cell 243 regular charge 244 replacing batteries 245 sediment 245 types 227 common-battery systems 228 magneto systems 228 Power switchboard 246 Private-branch exchanges 271 with automatic offices 278 secrecy 279 battery supply 279 circuits, key-type board 276 definitions 271 desirable features 281 functions of the private-branch exchange operator 272 marking of apparatus 281 private-branch switchboards 273 common-battery type 273 cord type 275 key type 275 magneto type 273 ringing current 280 supervision of private-branch connections 277 R Relays 28 Rotary connector 202 S Selecting switches 175 Selector 175 Simplex circuits 324 Storage battery 239 Storage cell 240 Stromberg-Carlson multiple board 96 Strowger automatic system 143 Subscribers' board 259-261 Switchboard assembly 31 T Table automanual system time data 225 automatic systems, messages per trunk in 305 calling rates 302 long-distance groups, messages per trunk in 305 manual system, messages per trunk in 304 out-trunking, effect of, on operator's capacity 303 subscribers' waiting time 226 Telephone traffic 298 importance of traffic study 300 methods of traffic study 301 observation of service 308 quality of service 305 accuracy and promptness 307 answering time 306 busy and don't answer calls 307 courtesy and form 307 disconnecting time 306 enunciation 308 team work 308 rates of calling 300 representative traffic data 302 calling rates 302 operators' loads 302 toll traffic 304 trunk efficiency 303 trunking factor 303 traffic variations 298 busy hour ratio 299 unit of traffic 298 Telephone train dispatching 333 advantages 335 apparatus 338 Cummings-Wray selector 342 dispatcher's transmitter 343 Gill selector 341 portable train sets 345 siding telephones 345 waystation telephones 344 Western Electric selector 338 blocking sets 355 causes of its introduction 334 Cummings-Wray circuits 350 on electric railways 356 Gill circuits 349 railroad conditions 337 rapid growth 333 test boards 353 transmitting orders 337 waystation circuits 348 Western Electric circuits 347 Telephone train-dispatching circuit Cummings-Wray 350 Gill 349 waystation 348 Western Electric 347 Test boards 353 Transfer switchboard 34 field of usefulness 41 handling transfers 38 limitations 40 plug-seat switch 38 transfer lines 35 jack-ended trunk 35 plug-ended trunk 37 Trunking in multi-office systems 109 classification 112 one-way trunks 103 two-way trunks 112 Kellogg trunk circuits 125 necessity for exchanges 109 Western Electric trunk circuits 116 W Warner pole changer 230 Waystation telephones 344 Western Electric mechanical signal 27 selector 338 trunk circuits 116 Transcriber's Notes. Spelling variants where it wasn't possible to determine the author's intent were left as is. These include: "clockwork" and "clock-work;" "doorkeeper" and "door-keeper;" "interrelation" and "inter-relation;" "multicyclic" and "multi-cyclic;" "redesign" and "re-design," along with derivatives. Added closing double quote in Steinmetz entry in list of authorities: "Theoretical Elements of Electrical Engineering." Changed "switch-hook" to "switch hook" on page 88: "the subscriber's switch hook." Page 107 says there is room for 300 banks of 100 multiple jacks, but then says this allows for 3,000 multiple jacks in all, rather than 30,000. Based on the figure, 300 banks should be 30 banks, which would correct the arithmetic. However, I did not change this. Changed "bi-paths" to "by-paths" on page 185: "circuits or by-paths." Changed "appararus" to "apparatus" on page 209: "The sectional apparatus." Changed "two number" to "two-number" on page 312: "the two-number calls are ticketed." On page 333, a paragraph begins with "It has been only within the past three few." Perhaps the author meant "It has been only within the past three years" or "It has been only within the past few years." But since I didn't know, I left is as is. Changed "them ain" to "the main" on page 333: "on the main line." Changed "weatherproof" to "weather-proof" on page 357: "iron weather-proof sets." Changed "interoffice" to "inter-office" three times on page 364, to match the spelling in the body of the document: "meant by inter-office trunking;" "inter-office connection system;" "of the inter-office connection." Changed "break-down" to "breakdown" on page 367: "provision against breakdown." Changed "way-station" to "waystation" twice on page 372: "with a waystation set;" and "a waystation on a block wire." Changed "way stations" to "waystations" on page 375, in the entry for Long-distance switching. Each page of the Index repeated this text: "Note.--For page numbers see foot of pages." They were removed.