"But are we praying for Private Hott, or for ourselves?" the man says. This is a poser. Everything becomes quiet as the meat saw stops moving. Shaftoe drops the wetsuit and stands up. Blanket Man's got very short grizzly hair, or maybe that's frost coalescing on his scalp. His ice colored eyes meet Shaftoe's through the mile-thick lenses of his RPGs, as if he's really expecting an answer. Shaftoe takes a step closer and realizes that the man is wearing a clerical collar.
"You tell me, Rev," Shaftoe says.
Then he recognizes Blanket Man. He's about to let fly with a lusty What in the fuck are you doing here,but something makes him hold back. The chaplain's eyes make a sideways dart so small and so fast that only Shaftoe, who's practically rubbing noses with him, could possibly see it.
The message being: Shut up, Bobby, we'll talk later.
"Private Hott is with God now-or wherever people go after they die," says Enoch "You can call me Brother" Root.
"What kind of an attitude is that!? Course he's with God. Jesus Christ! 'Wherever they go when they die.' What kind of a chaplain are you?"
"I guess I'm a Detachment 2702 kind of chaplain," the chaplain says. Lieutenant Enoch Root finally breaks eye contact with Shaftoe and turns his gaze to where the action is. "As you were, fellows," he says. "Looks like bacon tonight, huh?"
The men chuckle nervously and resume sawing.
Once they get the pig's carcass disentangled from Hott's, each of the Marines grabs a limb. They carry Hott out into the butcher shop, which has been temporarily evacuated for purposes of this operation, so that Hott's former comrades-in-shanks will not spread rumors.
Hasty evacuation of a butcher shop after one of its workers has been found dead on the floor could spawn a few rumors in and of itself. So the cover story du jour, freshly spun by Lieutenant Ethridge, is that Detachment 2702 is (contrary to all outward appearances) an elite, crack medical team concerned that Hott had been struck down by a rare new form of North African food poisoning. Maybe even something deliberately left behind by the French, who are, by accounts, a little irritable about having their battleship sunk. Anyway, the whole shop (the story goes) has to be shut down for the day and gone over with a nit comb. Hott's corpse will be cremated before being sent back to the family, just to make sure that the dreaded affliction does not spread into Chicago-the planetary abbatoir capital-where its incalculable consequences could alter the outcome of the war.
There is a GI coffin laid out on the floor, just to preserve the fiction. Shaftoe and his men ignore it completely and begin dressing the body, first in an appalling pair of swim trunks, then various components of the wetsuit.
"Hey!" Ethridge says. "I thought you were going to do the gloves last."
"Sir, we're doing them first, by your leave, sir!" Bobby Shaftoe says.
"On account of his fingers will thaw out first and once that happens we are screwed, sir!"
"Well, slap this on him first," Ethridge says, and hands over a wrist watch. Shaftoe hefts it and whistles. It's a beaut: a Swiss chronometer in solid uranium, its jewel-laden movement throbbing away like the heart beat of a small mammal. He swings it on the end of its wristband, made in cunningly joined armor plates. It is heavy enough to stun a muskellunge.
"Nice," Shaftoe says, "but it doesn't tell time too good."
"In the time zone where we are going," Ethridge says, "it does."
The chastened Shaftoe sets about his work. Meanwhile, Lieutenants Ethridge and Root are making themselves useful. They carry the crudely sawed remains of Frosty the Pig into the butcher shop and throw them on a gigantic scale. They add up to some thirty kilograms, whatever the fuck thatmeans. Enoch Root, showing an appetite for physical labor that is duly and silently noted by the men, hauls in another pig carcass, stiff as a Radio Flyer, and dumps it onto the scale, bringing the total up to seventy. Ethridge does the breaststroke through clouds of flies to gather up all the cuts of meat that were on the chopping blocks when the place was evacuated. He throws them on the scale and the needle swings up to near the one-hundred mark. From that point they are able to bring it up to one-thirty by ferrying hams and roasts in from the freezer one at a time. Enoch Root-who seems to be conversant with exotic systems of measurement-has made a calculation, and checked it twice, establishing that the weight of Gerald Hott, converted into kilograms, is one hundred and thirty.
All the meat goes into the coffin. Ethridge slams the lid shut, trapping some flies who have no idea what they are in for. Root goes around with a clawhammer, driving in sixteen-penny nails with sure, powerful, Carpenter-of-Nazareth-like strokes. Meanwhile, Ethridge has taken a GI manual out of his briefcase. Shaftoe is close enough to read the title, printed in block letters on its olive drab cover:
COFFIN SEALING PROCEDURES
PART III: TROPICAL ENVIRONMENTS
VOL. II: HIGH DISEASE RISK SITUATIONS (BUBONIC PLAGUE, ETC.)
The two lieutenants devote a good hour to following the instructions in that manual. The instructions are not that complicated, but Enoch Root keeps noticing syntactical ambiguities and wants to explore their ramifications. First this rattles Ethridge, then his emotions tend towards impatience and, finally, extreme pragmatism. To make the chaplain shut up, Ethridge confiscates the manual and starts Root on stenciling Hott's name on the coffin and pasting it up with red stickers printed with medical warnings so appalling that the topic headings alone induce faint nausea. By the time Root is finished, the only person who can legally open this coffin is General George C. Marshall himself, and even he would have to first get special permission from the Surgeon General and evacuate all living things within a hundred-mile radius.
"Chaplain talks kind of funny," says Private Nathan at one point, listening, slackjawed, to one of these Root/Ethridge debates.
"Yeah!" exclaims Private Branph, as if the accent took a really keen listener to notice. "What kind of an accent is that anyway?"
All eyes turn to Bobby Shaftoe, who pretends to listen for a bit and then says, "Well, fellas, I would guess that this Enoch Root is the offspring of a long line of Dutch and possibly German missionaries in the South Sea Islands, interbred with Aussies. And furthermore, I would guess that-being as how he grew up in territories controlled by the British-that he carries a British passport and was drafted into their military when the war started and is now part of ANZAC."
"Haw!" roars Private Daniels, "if you got all of that right, I'll give you five bucks."
"Deal," Shaftoe says.
Ethridge and Root finish sealing the coffin at about the same time Shaftoe and his Marines are wrestling the last bits of the wetsuit into place. It takes a shitload of talcum powder, but they get it done. Ethridge supplies them with the talcum powder, which is not GI talc; it is from somewhere in Europe. Some of the letters on the label have pairs of dots over them, which Shaftoe knows to be a characteristic of the German language.
A truck backs up to the loading dock, smelling the fresh paint (it is a Detachment 2702 truck). In go the sealed coffin and the now-vulcanized dead butcher.
"I'm going to stay behind and check the wastebaskets," Lieutenant Ethridge tells Shaftoe. "I'll meet you at the airfield in one hour."
Shaftoe imagines one hour in the back of a hot truck with this cargo. "You want me to keep him on ice, sir?" he asks.
Ethridge has to think about this one for a while. He sucks his teeth, checks his watch, hems and haws. But when he finally answers, he sounds definite. "Negative. It is imperative, for purposes of this mission, that we now get him into a thawed mode."
PFC General Hott and his meat-laden coffin occupy the center of the truck's bed. The Marines sit to the sides, arranged like pallbearers. Shaftoe finds himself staring across the carnage into the face of Enoch Root, which is wearing an expression of forced nonchalance.
Shaftoe knows he ought to wait, but he just can't stand it. "What are you doinghere?" he finally says.
"The detachment is relocating," the Rev says. "Closer to the front."
"We just got off the fucking boat," Shaftoe says. "Of course we're going closer to the goddamn front-we can't go any fartherunless we swim."
"As long as we're pulling up stakes," Root says coolly, "I'll be coming along for the ride."
"I don't mean that," Bobby Shaftoe says. "I mean, why should the detachment have a chaplain?"
"You know the military," Root says. "Every unit has to have one."
"It's bad luck."
"It's bad luckto have a chaplain? Why?"
"It means the waffle-butts are expecting a lot of funerals, is why."
"So you are taking the position that the only thing a cleric can do is to preside over funerals? Interesting."
"And weddings and baptisms," Shaftoe says. All of the other Marines chortle.
"Could it be you're feeling a little anxious about the unusual nature of Detachment 2702's first mission?" Root inquires, casting a significant glance at the late Hott, then staring directly into Shaftoe's eyes.
"Anxious? Listen, Rev, I done some things on Guadalcanal that make this look like Emily Fucking Post."
All of the other Marines think this is a great line, but Root is undeterred.
"Did you know why you were doing those things on Guadalcanal?"
"Sure! To stay alive."
"Do you know why you're doing this?"
"Fuck no."
"Doesn't that irritate you a little bit? Or are you too much of a stupid jarhead to care?"
"Well, you kind of backed me into a corner there, Rev," Shaftoe says. After a pause he goes on, "I'll admit to being a little curious.
"If there were someone in Detachment 2702 who could help answer your questions about why,would that be useful?"
"I guess so," Shaftoe grumbles. "It just seems weird to have a chaplain."
"Why does it seem weird?"
"Because of what kind of unit this is."
"What kind of unit isit?" Root asks. He asks it with a certain sadistic pleasure.
"We're not supposed to talk about it," Shaftoe says. "And anyway, we don't know."
Down the hill, immense zigzagging ramps descend pompously over rows of tiger-striped arches to the strand of ramifying railway lines that feed the port from the south. "It's like standing in the drain of a fucking pinball machine," says B. Shaftoe, looking up at the way they have just come, thinking about what might come rolling down out of the Casbah. They head south along those railway lines and come into a zone of ore dumps and coal heaps and smokestacks, clearly recognizable to Great Lakes Eagle Scout Shaftoe, but here operated through some kind of cross-cultured gear train about a million meshings deep. They pull up in front of the Socihim.There is also a Paperwork Negation Effect going on here; whenever Shaftoe expects to be stalled by the usual half an hour's worth of red tape, an anxious officer runs up and waves his hands furiously and he is allowed to proceed.
An Arab, wearing what appears to be a red coffee can on his head, hauls an iron door open; flames lunge at him and he beats them back with a blackened iron stick. The pallbearers center the head of the coffin in the opening and then shove it through, like ramming a big shell home into a sixteen-inch gun, and the man with the can on his head clangs the door shut, a tassel on the top of his can whipping around crazily. Before he's even got it latched he's yodeling just like those guys up in the Casbah. The officers all stand around agreeing with each other and signing their names on clipboards.
So with a dearth of complications that can only strike combat veteran Bobby Shaftoe as eerie, the truck leaves the Soci
"What is that? Chocolate?" Bobby Shaftoe asks.
"If it was chocolate," Root says, "that guy wouldn't have taken a Hershey bar for it."
Shaftoe shrugs. "Unless it's shitty chocolate."
"Or shit!" blurts Private Nathan, provoking incredible hilarity.
"You heard of Mary Jane?" Root asks.
Shaftoe-role model, leader of men-stifles the impulse to say, Heard of her?I've fuckedher!
"This is the concentrated essence," says Enoch Root.
"How would you know, Rev?" says Private Daniels.
The Rev is not rattled. "I'm the God guy here, right? I know the religious angle?"
"Yes, sir!"
"Well, at one time, there was a group of Muslims called the hashishinwho would eat this stuff and then go out and kill people. They were so good at it, they became famous or infamous. Over time the pronunciation of the name has changed-we know them as assassins."
There is an appropriately respectful silence. Finally, Sergeant Shaftoe says, "What the hell are we waiting for?"
They eat some. Shaftoe, being the highest-ranking enlisted man present, eats more than the others. Nothing happens. "Only person I feel like assassinating is that guy who sold it to us," he says.
* * *
The airfield, eleven miles out of town, is busier than it was ever intended to be. This is nice grape— and olive-growing land, but stony mountains are visible farther inland, and beyond 'em is a patch of sand the size of the United States-most of which seems to be airborne and headed their way. Countless airplanes-predominantly Dakota transports, a.k.a. Gooney Birds-stir up vast, tongue-coating, booger-nucleating dust clouds. It doesn't occur to Shaftoe for quite some time that his dry eyes and mouth may not be entirely the result of dust in the air. His saliva has the consistency of tile adhesive.
The detachment is so damn secret that no one at the airfield even knows that they exist. There are a lot of Brits here, and in the desert, Brits wear shorts, which makes Shaftoe want to punch them in the nose. He controls the urge. But his obvious hostility towards men in short pants, combined with the fact that he is demanding to be pointed in the direction of a unit that is so secret that he cannot specify it by name or even vaguely describe it, leads to a lot of bafflement, a lot of incredulity, and generally gets the Anglo-American alliance off on the wrong foot.
Sergeant Shaftoe, however, now understands that anything to do with this detachment is liable to be way off to one side, shrouded in black tarps and awnings. Like any other military unit, Detachment 2702 is rich in some supplies and poor in others, but they do appear to control about fifty percent of last year's total U.S. tarpage production. When Shaftoe mentions this fact, and goes on about it to his comrades at great length, some of the men look at him a little funny. It's left to Enoch Root to say, "Between the giant lizards and the black tarps some people might think you were acting a little paranoid."
"Let me tell you about paranoid," Shaftoe says, and he does, not forgetting to mention Lieutenant Ethridge and his wastebaskets. By the time he's had his say, the whole detachment has assembled on the far side of those tarps, and everyone is nice and tense except for their newest recruit, who, as Shaftoe notes approvingly, is beginning to relax. Lying on the bed of the truck in his wetsuit, he adjusts,rather than bounces, when they go over bumps.
Even so, he is still stiff enough to simplify the problem of getting him out of the truck and into their assigned Gooney Bird: a bare-knuckled variant of the DC-3, militarized and (to Shaftoe's skeptical eye) rendered somewhat less than airworthy by a pair of immense cargo doors gouged into one side, nearly cutting the airframe in half. This particular Dakota has been flying around in the fucking desert so long that all the paint's been sand-blasted off its propeller blades, the engine cowling, and the leading edges of the wings, leaving burnished metal that will make an inviting silver gleam for any Luftwaffe pilots within three hundred miles. Worse: diverse antennas sprout from the skin of the fuselage, mostly around the cockpit. Not just whip antennas but great big damn barbecue grills that make Shaftoe wish he had a hacksaw. They are eerily like the ones that Shaftoe humped down the stairway from Station Alpha in Shanghai-a memory that has somehow gotten all mangled together, now, with the other images in his head. When he tries to recollect it, all he can see is a bloodied Jesus carrying a high-frequency dual-band dipole down a stone staircase in Manila, and he knows that can't be right.
Though they are on the precincts of a busy airfield, Ethridge refuses to let this operation go forward when there is as much as a single airplane in the sky. Finally he says, "Okay, NOW!" In the truck, they lift the body up, just in time to hear Ethridge shout, "No, WAIT!" at which point they put him down again. Long after it has stopped being grimly amusing, they put a tarp on Gerald Hott and get him carried on board, and shortly thereafter are airborne. Detachment 2072 is headed for a rendezvous with Rommel.
Chapter 16 CYCLES
It is early in November of 1942 and a simply unbelievable amount of shit is going on, all at once, everywhere. Zeus himself would not be able to sort it all out, not even if he mobilized the caryatids-tell them never mind what we told you, just drop those loads. Temples collapsing everywhere, like spyglasses, he'd send those caryatids-and any naiads and dryads he could scare up-to library school, issue them green visors, dress them in the prim asexual uniforms of the OPAMS, the Olympian Perspective Archive Management Service, put them to work filling out three-by-five cards round the clock. Get them to use some of that vaunted caryatid steadfastness to tend Hollerith machines and ETC card readers. Even then, Zeus would probably still lack a handle on the situation. He'd be so pissed off he would hardly know which hubristical mortals to fling his thunderbolts at, nor which pinup girls and buck privates to molest.
Lawrence Pritchard Waterhouse is as Olympian as anyone right now. Roosevelt and Churchill and the few others on the Ultra Mega list have the same access, but they have other cares and distractions. They can't wander around the data flow capital of the planet, snooping over translators' shoulders and reading the decrypts as they come, chunkity-chunkity whirr,out of the Typex machines. They cannot trace individual threads of the global narrative at their whim, running from hut to hut patching connections together, even as the WRENs in Hut 11 string patch cables from one bombe socket to another, fashioning a web to catch Hitler's messages as they speed through the ether.
Here are some of the things Waterhouse knows: the Battle of El Alamein is won, and Montgomery is chasing Rommel westwards across Cyrenaica at what looks like a breakneck pace, driving him back toward the distant Axis stronghold of Tunis. But it's not the rout it appears to be. If Monty would only grasp the significance of the intelligence coming through the Ultra channel, he would be able to move decisively, to surround and capture large pockets of Germans and Italians. But he never does, and so Rommel stages an orderly retreat, preparing to fight another day, and plodding Monty is roundly cursed in the watch rooms of Bletchley Park for his failure to exploit their priceless but perishable gems of intelligence.
The largest sealift in history just piled into Northwest Africa. It is called Operation Torch, and it's going to take Rommel from behind, serving as anvil to Montgomery's hammer, or, if Monty doesn't pick up the pace a bit, maybe the other way around. It looks brilliantly organized but it's not really; this is the first time America has punched across the Atlantic in any serious way and so a whole grab bag of stuff is included on those ships-including any number of signals intelligence geeks who are storming theatrically onto the beaches as if they were Marines. Also included in the landing is the American contingent of Detachment 2702-a hand-picked wrecking crew of combat-hardened leathernecks.
Some of these Marines learned what they know on Guadalcanal, a basically useless island in the Southwest Pacific where the Empire of Nippon and the United States of America are disputing-with rifles-each other's right to build a military airbase. Early returns suggest that the Nipponese Army, during its extended tour of East Asia, has lost its edge. It would appear that raping the entire female population of Nanjing, and bayoneting helpless Filipino villagers, does not translate into actual military competence. The Nipponese Army is still trying to work out some way to kill, say, a hundred American Marines without losing, say, five hundred of its own soldiers.
The Japanese Navy is a different story-they know what they are doing. They have Yamamoto. They have torpedoes that actually explode when they strike their targets, in stark contrast to the American models which do nothing but scratch the paint of the Japanese ships and then sink apologetically. Yamamoto just made another attempt to wipe out the American fleet off the Santa Cruz Islands, sank Hornetand blew a nice hole in Enterprise.But he lost a third of his planes. Watching the Japanese rack up losses, Waterhouse wonders if anyone in Tokyo has bothered to break out the abacus and run the numbers on this Second World War thing.
The Allies are doing some math of their own, and they are scared shitless. There are 100 German U-boats in the Atlantic now, operating mostly from Lorient and Bordeaux, and they are slaughtering convoys in the North Atlantic with such efficiency that it's not even combat,just a Lusitanian-level murder spree. They are on a pace to sink something like a million tons of shipping this month, which Waterhouse cannot really comprehend. He tries to think of a ton as being roughly equivalent to a car, and then tries to imagine America and Canada going out into the middle of the Atlantic and simply dropping a million cars into the ocean-just in November. Sheesh!
The problem is Shark.
The Germans call it Triton. It is a new cypher system, used exclusively by their Navy. It is an Enigma machine, but not the usual three-wheel Enigma. The Poles learned how to break that old thing a couple of years ago, and Bletchley Park industrialized the process. But more than a year ago, a German U-boat was beached intact on the south coast of Iceland and gone over pretty thoroughly by men from Bletchley. They discovered an Enigma box with niches for four-not three-wheels.
When the four-wheel Enigma had gone into service on February 1st, the entire Atlantic had gone black. Alan and the others have been going after the problem very hard ever since. The problem is that they don't know how the fourth wheel is wired up.
But a few days ago, another U-boat was captured, more or less intact, in the Eastern Mediterranean. Colonel Chattan, who happened to be in the neighborhood, went there with sickening haste, along with some other Bletchleyites. They recovered a four-wheel Enigma machine, and though this doesn't break the code, it gives them the data they need to break it.
Hitler must be feeling cocky, anyway, because he's on tour at the moment, preparatory to a working vacation at his alpine retreat. That didn't prevent him from taking over what was left of France-apparently something about Operation Torch really got his goat, so he occupied Vichy France in its entirety, and then dispatched upwards of a hundred thousand fresh troops, and a correspondingly stupendous amount of supplies, across the Mediterranean to Tunisia. Waterhouse imagines that you must be able to cross from Sicily to Tunisia these days simply by hopping from the deck of one German transport ship to another.
Of course, if that were true, Waterhouse's job would be a lot easier. The Allies could sink as many of those ships as they wanted to without raising a single blond Teutonic eyebrow on the information-theory front. But the fact is that the convoys are few and far between. Just exactly how few and how far between are parameters that go into the equations that he and Alan Mathison Turing spend all night scribbling on chalkboards.
After a good eight or twelve hours of that, when the sun has finally come up again, there's nothing like a brisk bicycle ride in the Buckinghamshire countryside.
* * *
Spread out before them as they pump over the crest of the rise is a woods that has turned all of the colors of flame. The hemispherical crowns of the maples even contribute a realistic billowing effect. Lawrence feels a funny compulsion to take his hands off the handlebars and clamp them over his ears. As they coast into the trees, however, the air remains delightfully cool, the blue sky above unsmudged by pillars of black smoke, and the calm and quiet of the place could not be more different from what Lawrence is remembering.
"Talk, talk, talk!" says Alan Turing, imitating the squawk of furious hens. The strange noise is made stranger by the fact that he is wearing a gas mask, until he becomes impatient and pulls it up onto his forehead. "They love to hear themselves talk." He is referring to Winston Churchill and Franklin Roosevelt. "And they don't mind hearing each other talk-up to a point, at least. But voice is a terribly redundant channel of information, compared to printed text. If you take text and run it through an Enigma-which is really not all that complicated-the familiar patterns in the text, such as the preponderance of the letter E, become nearly undetectable." Then he pulls the gas mask back over his face in order to emphasize the following point: "But you can warp and permute voice in the most fiendish ways imaginable and it will still be perfectly intelligible to a listener." Alan then suffers a sneezing fit that threatens to burst the khaki straps around his head.
"Our ears know how to find the familiar patterns," Lawrence suggests. He is not wearing a gas mask because (a) there is no Nazi gas attack in progress, and (b) unlike Alan, he does not suffer from hay fever.
"Excuse me." Alan suddenly brakes and jumps off his bicycle. He lifts the rear wheel from the pavement, gives it a spin with his free hand, then reaches down and gives the chain a momentary sideways tug. He is watching the mechanism intently, interrupted by a few aftersneezes.
The chain of Turing's bicycle has one weak link. The rear wheel has one bent spoke. When the link and the spoke come into contact with each other, the chain will part and fall onto the road. This does not happen at every revolution of the wheel-otherwise the bicycle would be completely useless. It only happens when the chain and the wheel are in a certain position with respect to each other.
Based upon reasonable assumptions about the velocity that can be maintained by Dr. Turing, an energetic bicyclist (let us say 25 km/hr) and the radius of his bicycle's rear wheel (a third of a meter), if the chain's weak link hit the bent spoke on every revolution, the chain would fall off every one-third of a second.
In fact, the chain doesn't fall off unless the bent spoke and the weak link happen to coincide. Now, suppose that you describe the position of the rear wheel by the traditional [theta]. Just for the sake of simplicity, say that when the wheel starts in the position where the bent spoke is capable of hitting the weak link (albeit only if the weak link happens to be there to be hit) then [theta] = 0. If you're using degrees as your unit, then, during a single revolution of the wheel, [theta] will climb all the way up to 359 degrees before cycling back around to 0, at which point the bent spoke will be back in position to knock the chain off And now suppose that you describe the position of the chain with the variable C, in the following very simple way: you assign a number to each link on the chain. The weak link is numbered 0, the next is 1, and so on, up to l — 1 where l is the total number of links in the chain. And again, for simplicity's sake, say that when the chain is in the position where its weak link is capable of being hit by the bent spoke (albeit only if the bent spoke happens to be there to hit it) then C = 0.
For purposes of figuring out when the chain is going to fall off of Dr. Turing's bicycle, then, everything we need to know about the bicycle is contained in the values of [theta] and of C. That pair of numbers defines the bicycle's state. The bicycle has as many possible states as there can be different values of ([theta], C) but only one of those states, namely (0, 0), is the one that will cause the chain to fall off onto the road.
Suppose we start off in that state; i.e., with ([theta] = 0, C = 0), but that the chain has not fallen off because Dr. Turing (knowing full well his bicycle's state at any given time) has paused in the middle of road (nearly precipitating a collision with his friend and colleague Lawrence Pritchard Waterhouse, because his gas mask blocks his peripheral vision). Dr. Turing has tugged sideways on the chain while moving it forward slightly, preventing it from being hit by the bent spoke. Now he gets on the bicycle again and begins to pedal forward. The circumference of his rear wheel is about two meters, and so when he has moved a distance of two meters down the road, the wheel has performed a complete revolution and reached the position [theta] = 0 again-that being the position, remember, when its bent spoke is in position to hit the weak link.
What of the chain? Its position, defined by C, begins at 0 and reaches 1 when its next link moves forward to the fatal position, then 2 and so on. The chain must move in synch with the teeth on the sprocket at the center of the rear wheel, and that sprocket has n teeth, and so after a complete revolution of the rear wheel, when [theta] = 0 again, C = n.