started out of the door. Sergeant Bellews followed atleisure. He painstakingly avoided ever walking the regulation two pacesbehind a commissioned officer. Either he walked side by side, chatting,or he walked alone. Wise officers let him get away with it.

  * * * * *

  Reaching the open air a good twenty yards behind the lieutenant, hecocked an approving eye at a police-up unit at work on the lawn outside.Only a couple of weeks before, that unit had been in a bad way. Itstopped and shivered when it encountered an unfamiliar object.

  But now it rolled across the grass from one path-edge to another. Whenit reached the second path it stopped, briskly moved itself its ownwidth sidewise, and rolled back. On the way it competently manicured thelawn. It picked up leaves, retrieved a stray cigarette-butt, and snappedup a scrap of paper blown from somewhere. Its tactile units touched anew-planted shrub. It delicately circled the shrub and went on upon itsproper course.

  * * * * *

  Once, where the grass grew taller than elsewhere, it stopped andwhirred, trimming the growth back to regulation height. Then it went onabout its business as before.

  Sergeant Bellews felt a warm sensation. That was a good machine that hadbeen in a bad way and he'd brought it back to normal, happy operation.The sergeant was pleased.

  The lieutenant turned into the Communications building. Sergeant Bellewsfollowed at leisure. A jeep went past him--one of the special jeepsbeing developed at this particular installation--and its driver wastalking to someone in the back seat, but the jeep matter-of-factlyturned out to avoid Sergeant Bellews. He glowed. He'd activated it.Another good machine, gathering sound experience day by day.

  He went into the room where Betsy stood--the communicator which, aloneamong receiving devices in the whole world, picked up the enigmaticbroadcasts consistently. Betsy was a standard Mark IV communicator, nowcarefully isolated from any aerial. She was surrounded by recordingdevices for vision and sound, and by the most sensitive and complicatedinstruments yet devised for the detection of short-wave radiation.Nothing had yet been detected reaching Betsy, but something must. Nomachine could originate what Betsy had been exhibiting on her screen andemitting from her speakers.

  Sergeant Bellews tensed instantly. Betsy's standby light quiveredhysterically from bright to dim and back again. The rate of quiveringwas fast. It was very nearly a sine-wave modulation of the light--andwhen a Mahon-modified machine goes into sine-wave flicker, it is thesame as Cheyne-Stokes breathing in a human.

  He plunged forward. He jerked open Betsy's adjustment-cover and fairlyyelped his dismay. He reached in and swiftly completed correctivechanges of amplification and scanning voltages. He balanced a capacitybridge. He soothed a saw-tooth resonator. He seemed to know by sheerintuition what was needed to be done.

  After a moment or two the standby lamp wavered slowly fromnear-extinction to half-brightness, and then to full brightness andback again. It was completely unrhythmic and very close to normal.

  "Who done this?" demanded the sergeant furiously. "He had Betsy close tofatigue collapse! He'd ought to be court-martialed!"

  He was too angry to notice the three civilians in the room with thecolonel and the lieutenant who'd summoned him. The young officer lookeduncomfortable, but the colonel said authoritatively:

  "Never mind that, Sergeant. Your Betsy was receiving something. Itwasn't clear. You had not reported, as ordered, so an attempt was madeto clarify the signals."

  "Okay, Colonel!" said Sergeant Bellews bitterly. "You got the right tospoil machines! But if you want them to work right you got to treat 'emright!"

  "Just so," said the colonel. "Meanwhile--this is Doctor Howell, DoctorGraves, and Doctor Lecky. Sergeant Bellews, gentlemen. Sergeant, theseare not MDs. They've been sent by the Pentagon to work on Betsy."

  * * * * *

  "Betsy don't need workin' on!" said Sergeant Bellews belligerently."She's a good, reliable, experienced machine! If she's handled right,she'll do better work than any machine I know!"

  "Granted," said the colonel. "She's doing work now that no other machineseems able to do--drawing scrambled broadcasts from somewhere that canonly be guessed at. They've been unscrambled and these gentlemen havecome to get the data on Betsy. I'm sure you'll cooperate."

  "What kinda data do they want?" demanded Bellews. "I can answer mostquestions about Betsy!"

  "Which," the colonel told him, "is why I sent for you. These gentlemenhave the top scientific brains in the country, Sergeant. Answer theirquestions about Betsy and I think some very high brass will be grateful.

  "By the way, it is ordered that from now on no one is to refer to Betsyor any work on these broadcasts, over any type of electroniccommunication. No telephone, no communicator, no teletype, no radio, noform of communication except _viva voce_. And that means you talking tosomebody else, Sergeant, with no microphone around. Understand? And fromnow on you will not talk about anything at all except to these gentlemenand to me."

  Sergeant Bellews said incredulously:

  "Suppose I got to talk to somebody in the Rehab Shop. Do I signal withmy ears and fingers?"

  "You don't talk," said the colonel flatly. "Not at all."

  Sergeant Bellews shook his head sadly. He regarded the colonel with suchreproach that the colonel stiffened. But Sergeant Bellews had a gift formachinery. He had what amounted to genius for handling Mahon-modifieddevices. So long as no more competent men turned up, he was apt to getaway with more than average.

  The colonel frowned and went out of the room. The tall young lieutenantfollowed him faithfully. The sergeant regarded the three scientists withthe suspicious air he displayed to everyone not connected with Mahonunits in some fashion.

  "Well?" he said with marked reserve. "What can I tell you first?"

  Lecky was the smallest of the three scientists. He said ingratiatingly,with the faintest possible accent in his speech:

  "The nicest thing you could do for us, Sergeant, would be to show usthat this--Betsy, is it?--with other machines before her, has developeda contagious machine insanity. It would frighten me to learn thatmachines can go mad, but I would prefer it to other explanations for themessages she gives."

  "Betsy can't go crazy," said Bellews with finality. "She'sMahon-controlled, but she hasn't got what it takes to go crazy. A Mahonunit fixes a machine so it can loaf and be a permanent dynamic systemthat can keep acquired habits of operatin'. It can take trainin'. It canget to be experienced. It can learn the tricks of its trade, so tospeak. But it can't go crazy!"

  "Too bad!" said Lecky. He added persuasively: "But a machine can lie,Sergeant? Would that be possible?"

  Sergeant Bellews snorted in denial.

  * * * * *

  "The broadcasts," said Lecky mildly, "claim a remarkable reason forcertainty about an extremely grave danger which is almost upon theworld. If it's the truth, Sergeant, it is appalling. If it is a lie, itmay be more appalling. The Joint Chiefs of Staff take it very seriously,in any case. They--"

  "I got cold shivers," said Sergeant Bellews with irony. "I'm all wroughtup. Huh! The big brass gets the yellin' yollups every so often anyhow.Listen to them, and nothin' happens except it's top priority top secretextra crash emergency! What do you want to know about Betsy?"

  There was a sudden squealing sound from the communicator on which allthe extra recording devices were focussed. Betsy's screen lighted up.Peculiarly curved patterns appeared on it. They shifted and changed.Noises came from her speaker. They were completely unearthly. Now theywere shrill past belief, and then they were chopped into very small bitsof sound, and again they were deepest bass, when each separate noteseemed to last for seconds.

  "You might," said Lecky calmly, "tell us from where your Betsy gets thesignal she reports in this fashion."

  There were whirrings as recorders trained upon Betsy captured everyflickering of her screen and every peeping noise or deep-toned rumble.The
screen-pattern changed with the sound, but it was not linked to it.It was a completely abnormal reception. It was uncanny. It was somehowhorrible because so completely remote from any sort of humancommunication in the year 1972.

  The three scientists watched with worried eyes. A communicator, evenwith a Mahon unit in it, could not originate a pattern like this! Andthis was not conceivably a distortion of anything transmitted in anynormal manner in the United States of America, or the Union of Compubs,or any of the precariously surviving small nations not associated witheither colossus.

  "This is a repeat broadcast!" said one of the three men suddenly. It wasHowell, the heavy-set man. "I remember it. I saw it