that we've broken their codes.'
'An informal system has been in place, which might be thought of as a precursor to Detachment 2701, or 2702 or whatever we are calling it,' Alan says. 'When we want to sink a convoy, we send out an observation plane first. It is
Alan stops, consults his compass, turns ninety degrees, and begins pacing westwards.
'That strikes me as being a very ad hoc arrangement,' Lawrence says. 'What is the likelihood that Allied observation planes, sent out purportedly at random, will just happen to notice every single Axis convoy?'
'I've already calculated that probability, and I'll bet you one of my silver bars that Rudy has done it too,' Turing says. 'It is a very small probability.'
'So I was right,' Lawrence says, 'we have to assume that the jig is up.'
'Perhaps not just yet,' Alan says. 'It has been touch and go. Last week, we sank a convoy in the fog.'
'In the fog?'
'It was foggy the whole way. The convoy could not possibly have been observed. The imbeciles sank it anyway. Kesselring became suspicious, as would anyone. So we ginned up a fake message-in a cypher that we know the Nazis have broken-addressed to a fictitious agent in Naples. It congratulated him on betraying that convoy to us. Ever since, the Gestapo have been running rampant on the Naples waterfront, looking for the fellow.'
'We dodged a bullet there, I'd say.'
'Indeed.' Alan stops abruptly, takes the metal detector from Lawrence, and turns it on. He begins to walk slowly across a clearing, sweeping the wire loop back and forth just above the ground. It keeps snagging on branches and getting bent out of shape, necessitating frequent repairs, but remains stubbornly silent the whole time, except when Alan, concerned that it is no longer working, tests it on Lawrence's belt buckle.
'The whole business is delicate,' Alan muses. 'Some of our SLUs in North Africa-'
'SLUs?'
'Special Liaison Units. The intelligence officers who receive the Ultra information from us, pass it on to field officers, and then make sure it is destroyed. Some of them learned, from Ultra, that there was to be a German air raid during lunch, so they took their helmets to the mess hall. When the air raid came off as scheduled, everyone wanted to know why those SLUs had known to bring their helmets.'
'The entire business seems hopeless,' Lawrence says. 'How can the Germans not realize?'
'It seems that way to us because we know everything and our channels of communication are free from noise,' Alan says. 'The Germans have fewer, and much noisier, channels. Unless we continue to do stunningly idiotic things like sinking convoys in the fog, they will never receive any clear and unmistakable indications that we have broken Enigma.'
'It's funny you should mention Enigma,' Lawrence says, 'since that is an extremely noisy channel from which we manage to extract vast amounts of useful information.'
'Precisely. Precisely why I am worried.'
'Well, I'll do my best to spoof Rudy,' Waterhouse says.
'You'll do fine. I'm worried about the men who are carrying out the operations.'
'Colonel Chattan seems pretty dependable,' Waterhouse says, though there's probably no point in continuing to reassure Alan. He's just in a fretting mood. Once every two or three years, Waterhouse does something that is socially deft, and now's the time: he changes the subject: 'And meanwhile, you'll be working it out so that Churchill and Roosevelt can have secret telephone conversations?'
'In theory. I rather doubt that it's practical. Bell Labs has a system that works by breaking the waveform down into several bands...' and then Alan is off on the subject of telephone companies. He delivers a complete dissertation on the subject of information theory as applied to the human voice, and how that governs the way telephone systems work. It is a good thing that Turing has such a large subject on which to expound, for the woods are large, and it has become increasingly obvious to Lawrence that his friend has no idea where the silver bars are buried.
Unburdened by any silver, the two friends ride home in darkness, which comes surprisingly early this far north. They do not talk very much, for Lawrence is still absorbing and digesting everything that Alan has disgorged to him about Detachment 2702 and the convoys and Bell Labs and voice signal redundancy. Every few minutes, a motorcycle whips past them, saddlebags stuffed with encrypted message slips.
Chapter 17 ALOFT
Any way that livestock can travel, Bobby Shaftoe has too, boxcars, open trucks, forced cross-country marches. Military has now invented the airborne equivalent of these in the form of the Plane of a Thousand Names: DC-3, Skytrain, C-47, Dakota Transport, Gooney Bird. He'll survive. The exposed aluminum ribs of the fuselage are trying to beat him to death, but as long as he stays awake, he can fend them off.
The enlisted men are jammed into the other plane. Lieutenants Ethridge and Root are in this one, along with PFC Gerald Hott and Sergeant Bobby Shaftoe. Lieutenant Ethridge got dibs on all of the soft objects in the plane and arranged them into a nest, up forward near the cockpit, and strapped himself down. For a while he pretended to do paperwork. Then he tried looking out the windows. Now he has fallen asleep and is snoring so loudly that he is, no fooling, drowning out the engines.
Enoch Root has wedged himself into the back of the fuselage, where it gets narrow, and is perusing two books at once. It strikes Shaftoe as typical-he supposes that the books say completely different things and that the chaplain is deriving great pleasure from pitting them against each other, like those guys who have a chessboard on a turntable so that they can play against themselves. He supposes that when you live in a shack on a mountain with a bunch of natives who don't speak any of your half-dozen or so languages, you have to learn to have arguments with yourself.
There's a row of small square windows on each side of the plane. Shaftoe looks out to the right and sees mountains covered with snow and gets scared shitless for a moment thinking maybe they've strayed into the Alps. But off to the left, it still looks like the Mediterranean, and eventually it gives way to Devil's Tower type outcroppings rising up out of stony scrubland, and then after that it is just rocks and sand, or sand without the rocks. Sand puckered here and there, for no particular reason, by clutches of dunes. Damn it, they are still in Africa! You ought to be able to see lions and giraffes and rhinos! Shaftoe goes forward to lodge a complaint with the pilot and copilot. Maybe he can get a card game together. Maybe the view out the
He is, on all counts, thrown back in stinging defeat. He sees immediately that the project of finding a better view is doomed. There are only three things in the whole universe: sand, sea, and sky. As a Marine, he knows how boring the sea is. The other two are little better. There is a line of clouds far ahead of them-a front of some description. That's all there is.
He gets a general notion of their flight plan before the chart is snatched away and stashed out of his view. They seem to be attempting to fly across Tunisia, which is kind of funny, because last time Shaftoe checked, Tunisia was Nazi territory-the anchor, in fact, of the Axis presence on the African continent. Today's general flight plan seems to be that they'll cut across the straits between Bizerta and Sicily, then head east to Malta.
All of Rommel's supplies and reinforcements come across those very straits from Italy, and land at Tunis or Bizerta. From there, Rommel can strike out east towards Egypt or west towards Morocco. In the several weeks since the British Eighth Army kicked the crap out of him at El Alamein (which is way, way over there in Egypt) he has been retreating westwards back towards Tunis. In the few weeks since the Americans landed in Northwest Africa, he's been fighting on a second front to his west. And Rommel has been doing a damn good job of it, as far as Shaftoe can tell from listening between the stentorian lines of the Movietone newsreels, so laden with sinister cheer, whence the above facts were gleaned.
