Fruit of The Difference Engine

Back to Contents

    This story contemplates the differences that a calculating engine could have made in the history of the last century and a half had Charles Babbage succeeded in building and operating his first Difference Engine. I conceived the story 1993 Mar 25 while I was riding the bus to UCLA to conduct research into Charles Babbage and into the mathematics, especially the theorem of finite differences, that he used in the design of his mechanical computer.


    Upon entering Percival Norcroft's apartment Naomi Prendergast was immediately enchanted by the oompah-squeal of "Low Earth Orbit", the latest klezmer-swing hit from the Jerry Dorsey Band, emanating from the radio in the parlor. She danced a few steps before allowing Percy to take her cape and put it on the coatrack. She put her hat, gloves, and purse on the shelf next to the rack and then greeted Percy with a kiss on the cheek. After an exchange of the appropriate pleasantries she handed him the quarto-sized magazine that she had been carrying, the latest issue of Analogue: Scientific Romances and Scientific Essays, and smiled expectantly.

    "So, what do you think of Mister Flynn's little conceit?" he asked as he took her proffered arm in his and escorted her to the parlor.

    "Chilling," she said with a wry smile. "Why the very idea! To think that Sir Charles Babbage would conspire with a secret society devoted to employing the Analytical Engine to perform calculations pertaining to the Doctrine of Cycles, thereby gaining the power to manipulate history. And the name that he gave to his conspirators! Why did he call them 'whackers'? He gave no reason in the story."

    Percy brought her into the parlor and guided her to an armchair facing the wide windows looking over the south end of Manhattan. Late afternoon shadows were deepening in the city.

    "He gave the reason in a previous, related story," Percy said as Naomi seated herself. "He described his conspirators as being like unto a band of wild Indians bushwhacking Analytical Engines, commandeering them while they were unattended, performing their calculations, and then stealing tracelessly away like unto shadows before the sun's rays."

    "It carries a hint of violence," Naomi said, nodding in understanding. "And the plausibility of it all raises -- in my mind, at least -- the thought that it might actually be true to Reality, that such a secret society may actually exist and be manipulating the lives of nations. Oh, Percy, do you suppose that Mister Flynn intends these stories to be a kind of exposÚ, a coded warning to Humanity?"

    Percy had gone to the sideboard and lifted up the hatch on the chiller. He used silver tongs to pull ice cubes from the chiller and put them into a pair of tall glasses.

    "No, of course not," he said. "Such a populous conspiracy could not be kept secret for long. Besides," he continued as he closed the chiller and filled the two glasses with pale-green carbonated apple-mint cola, "as a physicist you should be able to estimate the difficulty of their anticipating discoveries in the fields of science and invention."

    "Yes, you're right," she said as she accepted the glass that he offered her. "There's no reasonable way by which they could have anticipated Professor Einstein's theory of spatio-temporal invariants or the aleatric dynamics of Heisenberg and Schr÷dinger; and certainly the discoveries of Schwarzschild would lie beyond their reach. So such a conspiracy cannot truly exist. But it was quite spooky to read of it, even if it were entirely fictitious. I wasn't sure whether I was reading a scientific romance or a horrific tale."

    Percy settled into his own chair, also facing the windows, and half turned toward Naomi. He reached out with his glass and touched hers in salute.

    "I believe that the two genres overlap," he said, "each the other in many places. Surely, after all, when one goes exploring in the Realm of Whatif, one is as likely to find horrors as well as delights."

    "So I gained a little of both," she said, raising her glass. "The bubbly sweetness of scientific advancement served with a slight chill of subhuman depravity."

    "You have often said that a brisk shudder of the spine can do one good," he said.

    "Aye, so I have," she said in a mock Irish accent. Putting her hand on her knee, she leaned toward him and looked at him through one eye. "But this pirate story, matey, was not sufficient to shiver me timbers."

    "Really?" he said.

    "Yes," she said, resuming her normal composure. "It was indeed chilling, but in the manner of 'Frankenstein'. Mister Flynn's Analytical Society reminded me of Herr Doktor Frankenstein's creature, the pathetic thing striving and yet failing to do good. So much like unto our own Humanity. No, real horror is the attractive evil. That cineplay that we saw, the one about the tragedy of Count Dracula, is a perfect example. That was a three-nighter."

    "A three-nighter?" Percy said. "What does that mean?"

    "It means that the cineplay -- or, rather, the memory of it -- made me lose three nights of sleep. That's how I rate horrific tales. If you want to impress me with a scientific ghost story, you shall have to do better."

    "Yes, but not too much better, I should think."

    She took a sip of her cola and then gave him a searching look. He tried to return her gaze casually, but blushed nonetheless.

    "Why, Percy," she said, "I believe you have got one."

    He gave her a half smile and nodded. "You would call it a ten-nighter, possibly more."

    "Oh, you must let me read it," she said.

    "It's not written," he said, "and it never shall be."

    "You mean to tell me that you have contrived a story that has deprived you of nearly two weeks' sleep?" she exclaimed in wide-eyed delight. "How wonderful! If you won't write it down, then you must at least tell it to me."

    Percy shook his head. "It's too...upsetting. I could never forgive myself if I were to put into your mind the revolting images that came into mine as a consequence of my contemplation of this subject."

    "Oh, gallant Percy," Naomi said, "proceed cautiously in the telling and I shall ask you to stop if your imagery becomes too gruesome and upsetting. We have plenty of time before the fireworks begin and I do want to see what the Muse has brought you."

    "As you wish," he said. "I shall be cautious, but I must rely upon you to give me adequate warning before I describe anything excessively revolting."

    "Agreed," she said. "Begin by telling me your conceit."

    "Well, I was inspired by Mister Flynn," he said, "but I took my exploration of the Realm of Whatif into a direction opposite the one he chose. In my conceit Charles Babbage failed to complete Difference Engine Number One and, therefore, never built Difference Engine Number Two nor Analytical Engine Number One."

    "Percy, dear," Naomi said gently, "that's preposterous. The creation of the Difference Engines and the Analytical Engines was inevitable once Mister Babbage got the project started."

    "In retrospect that seems true simply because it actually happened that way," he said. "Many events that seem to us to have been inevitable actually were not so. In my particular example I direct your attention to the state of Mister Babbage's project in the Spring of 1833."

    "My command of historical fact fails me there," she said. "You shall be obliged to paint the picture for my mind's eye."

    "And I shall fulfill that obligation," he said. "History tells us that Mister Babbage's chief engineer, the much reviled Mister Clement, had allowed avarice to get the better of him. He had been submitting questionable bills for years and when the government required that the project be moved to a fireproof building on Mister Babbage's property he demanded a higher rate of pay. Mister Babbage, whose project had already cost the government thousands of pounds, refused to pay the higher rate, so on April Tenth Mister Clement dismissed his workers and quit the project. Under English law at the time the tools that had been invented and refined for the project were Mister Clement's property. Fortunately he offered to sell the tools to the government. Members of the Royal Society, who had supported the project from its inception, convinced the Chancellor of the Exchequer to negotiate the purchase of the tools and when those negotiations succeeded Mister Babbage was able to hire a new engineer and complete the project. My conceit is that those negotiations were not made and that, therefore, the project was ultimately abandoned."

    "But surely Mister Babbage could have recreated the necessary tools," Naomi protested.

    "He didn't have drawings of the tools," Percy said. "His only drawings were of the Difference Engine itself. The new engineer, had one been engaged, would thus have been required to reinvent the tools from guess and sketch."

    "That doesn't seem to me to be a fatal obstacle to the project's success," she said.

    "Nor did it to me at first impression," he said, "until I recalled that I was looking at the incident across more than a century and a half of subsequent progress. The construction of that one calculating machine actually cost more than the expense of building a railroad locomotive of the time, a truly considerable expense. And Mister Babbage was forcing the practical mechanics of the time into a regime that people then regarded, quite rightly, as far futuristic, something that we would regard as coming from a scientific romance. It was because of that fact, because of the intense novelty of that intricate brasswork and of the innovation it required, that the project's cost far exceeded Mister Babbage's original estimate and at the time of the incident with Mister Clement the Chancellor of the Exchequer was already questioning the financial wisdom of continuing the project. The prospect of starting the project virtually from its beginning would certainly have convinced him to abandon it altogether."

    "Didn't they perform a cost-versus-benefit analysis?" she asked. "They had to possess some idea of the value of the Difference Engine."

    "Yes, actually, they did," he said. "You must understand that this was an unusual project for its time. The British government normally did not get involved in the process of invention. Mister Babbage's project was made an exception to that rule for two reasons. First and more importantly, the machine was meant to generate error-free ephemerides and other mathematical tables useful to navigation, which would have had great value to the British navy. The second reason that came into play was that no one could foresee any other use for the machine that would make it economically viable on the free market, so if the machine were to be built at all, it would have to be built at government expense. The other uses to which the Difference Engine was put were only discovered after it became available and people had become acquainted with it."

    "Very well, then," she said, "let's accept your conceit as plausible. I'm thinking that it would exert only a small effect upon history because eventually someone else would have invented the Analytical Engine."

    "I agree with your latter point," he said, "but I wonder how much time must elapse before eventually comes to pass? You might recall that Heron of Alexandria invented a crude steam turbine in the First Century of Our Lord's Promise. It wasn't developed into anything that could reasonably be called a true steam engine and the opportunity to develop that particular technology and thereby bestow the Industrial Metamorphosis upon the Roman Empire was lost. The next modestly successful attempt to invent a steam engine was that of Thomas Savery at the end of the Seventeenth Century. Savery's engine was the device that was eventually improved by James Watt."

    "Yes, I see," she said. "But I doubt that sixteen centuries would elapse before the rediscovery of the Difference Engine. How could the Industrial Metamorphosis have progressed as it did without the Analytical Engines and Difference Engines interconnected via the telegraph? I believe that there would have been considerable pressure exerted to revive Mister Babbage's project and the resistance to that pressure would certainly have weakened as the technology of brassworking advanced. Don't you agree?"

    "Partly yes and partly no," he said. "I believe that after the failure of Mister Babbage's project people would have believed for a long time, perhaps as long as a century, that Difference Engines are infeasible if not impossible to build. And one century of delay in the invention of the Difference Engine is sufficient to wreak horrible changes in the course that history takes."

    "You're claiming in your conceit, then," she said, "that calculating engines would not have been invented until their designs could be based upon micro-electronic elements. Why in such a world the telegraph would have been virtually useless until well into the Twentieth Century. The transmission and reception of information would have relied entirely upon human operators: it would have been unbearably slow!"

    "Yes," he said, "that's exactly what I assumed. And that slowness combined with the lack of information sorting capability is what would have transmuted a minor incident in the Summer of 1914 into the horror that came before my mind's eye."

    "What incident?" she asked.

    "Few people know how close Europe came to total war in that overheated summer," he said slowly. "On the 28th day of June in that fulcrum year Franz Ferdinand, Archduke of Austria-Este, Prince Imperial of Austria and Royal Prince of Hungary and Bohemia, and his wife Sophie, Duchess of Hohenburg, were visiting Sarajevo in the Bosnia province of Austro-Hungary. A Srpski anarchist murdered them and the government of Austro-Hungary made demands on Srbija that amounted to a solicitation of a declaration of war."

    "But of course cooler heads prevailed," she said.

    "Yes, of course," he replied, "but I assumed that they did not. I assumed that the nations had mobilized their armies for war and, due to the inability to process and move information at a reasonable rate could not demobilize them without rendering them vulnerable to an attack."

    "So the armies had to remain mobilized," she guessed, "until some arrangement could be worked out to move them safely. But in the summer heat, sooner or later, someone will fire a shot, as at Lexington in our Revolution."

    "Indeed, so I assumed," he said. "Like unto a wildfire, the war would have swiftly swept across Europe and even into Asia."

    "Asia? How so?"

    "The Osmanli Empire has most of its area in Asia" he replied, "but it also has that area around Istanbul that lies in Europe. I believe that the Osmanite Turks would have joined Germany and the Austro-Hungarian Empire against Britain, France, and the Russian Empire in this conflict."

    "How would such a war be fought?" she asked.

    "Ah, now we get to the horror," he said. "I believe that it would have happened much as the Civil War did, but with more advanced weaponry. Indeed, the warring nations would have been forced into a kind of pseudo-Darwinian struggle to mutate their forces with improved weaponry. Remember that in the Civil War the armies started the war using muzzle-loading rifles, but by the end of the war they had begun to acquire breech-loading ammunition based on brass cartridges."

    "And we may as well recall to mind the advent of the iron-clad warship," she said.

    "Yes," he said. "But let us consider only the land, where almost all of the fighting would have occurred. Consider the rapid-fire gun pioneered by Gatling. If somebody could have made one that was driven by a small gasoline engine, his nation would have gained a horrible weapon. On a battlefield a gunner need only aim the motor-gun and engage the clutch to take the Grim Reaper's scythe in hand and mow down a whole battalion of men."

    "What a horrid notion," she said. "How could an army charge an enemy so armed?"

    Percy shook his head. "I cannot imagine any general officer stupid enough to order a charge against a motorized gun. No, I believe that in this fantastic war the armies would have rediscovered medieval tactics. They would have had to dig trenches in which their soldiers could crouch to avoid the Hellish fire coming from their opponents, who would be crouching in their own trenches. In those circumstances the greatest killer would have been disease, as it has always been in war."

    "Percy, my dear," Naomi said gently, "I believe that this would not have been much of a war. Once the armies got into their trenches they would have achieved a stall-mate. No one could move and capture territory. The war would end almost as quickly as it had begun."

    "Sweet Naomi," Percy said, "how lovely that your mind cannot conceive the full horror that emerged from mine. Perhaps we should indeed let this imaginary war end there?"

    "Not a chance," she said. "You gave me a promise and I want full payment on it."

    Percy sighed. "Very well. The trenches would not be impregnable. Let's ignore the fact that the soldiers would be ever digging and extending their trenches in ways intended to gain some advantage over their enemies. I saw in my fever dream a truck with large iron wheels and a very low gear that would enable it to travel over almost any terrain or obstacle. A carapace made of iron plates would cover the truck and protect the soldiers inside it and a turret on top would carry a cannon or a motorized gun."

    "It would bear a resemblance to an iron tortoise," she commented.

    "Yes," he said. "Relatively invulnerable to an attack, like unto some mobile fortress, a war tortoise would approach an enemy trench and the soldiers inside could then fire through gunports at their enemy. Or worse. Consider a small bomb whose iron casing is so scored that it breaks up into a spray of bullet-like fragments when it explodes: a soldier armed with such hand bombs would be a formidable opponent. If he could sneak his way close to an enemy's trench, he could lob several hand bombs into the trench and defeat the enemy's troops before they could react. Soldiers inside a war tortoise would certainly carry a good supply of such hand bombs."

    "But the war tortoise itself is not completely invulnerable, is it?" she said.

    "No," Percy replied. "It would be vulnerable to artillery. All the more so because cannon would no longer project solid balls, but would throw shells packed with explosive, thereby magnifying the destructive power of a hit. I pity any man, friend or foe, who sits in a war tortoise when an explosive shell hits it."

    "So the war tortoises must remain safe in their burrows and you have come back to stall-mate," she said. "Or have you?"

    "A campaign would have to begin with great thunderstorms of artillery duels," he said. "But, knowing that fact, the nations would have developed cannon that could lob their shells many miles. Such cannon could be hidden in the terrain around a battlefield. So how can I locate my enemy's cannon so that I can attack them with my own cannon?"

    "You would borrow an idea from our own Civil War," she replied. "You would use spotters riding in baskets suspended beneath balloons."

    "Only until someone shoots down my balloons," he said. "If I can build cannon with a range of many miles, then I can certainly build a kind of rifle that can send its bullet far enough and high enough to hit a balloon. It might be a fairly heavy weapon that I would be obliged to mount on some kind of carriage, but I would want to do that anyway because I would want to motorize it so that it would fire very quickly and ensure that at least one in the stream of bullets it projects would hit the enemy's balloon."

    "So your cannons remain hidden and the stall-mate stands," she said.

    Percy shook his head sadly and said, "What magnificent machine was invented about eleven years before this imaginary war started?"

    "In 1903? Why, the airplane, of course! Oh, but Percy, using an airplane as a war machine?!''s just inconceivable!!"

    "You just conceived it," he replied. "How much more quickly would minds of less kindly intent do the same?"

    "But the airplanes of the time were fragile,...flimsy things," she objected. "Surely they couldn't...."

    "At first, I saw, they would be used for spotting enemy artillery and troop deployments. I would use a simple two-seat airplane and give the man in the passenger seat a camera with a telephoto lens. The airplane moves too fast for a rifleman on the ground to get a good aim on it, so these spy missions would remain relatively safe. The pilot flies his airplane over the enemy positions, the cameraman snaps his pictures, then the pilot flies quickly back to his base, where the pictures are developed and then projected onto maps. Artillery officers then plot the locations of suitable targets for bombardment."

    "So the rifleman doesn't stay on the ground, does he," she said. "He gets into his own airplane and goes up to shoot your aerial spy."

    Percy sat slumped in his chair. "It's even easier than that," he said slowly, reluctantly. "Build an airplane with two engines, one mounted on each wing, and put a third engine in front of the pilot."

    "That third engine turns a Gatling gun, doesn't it?" she guessed.

    "Yes," he said. "Such an airplane needs only a pilot and the pilot need only fly his airplane toward a target and engage the clutch on his motor-gun in order to wreak great damage. He could even attack targets on the ground. Imagine the result of a few well-placed shots fired into an ammunition magazine."

    "Or spraying a troop train," she added, her eyes wide in horror. "They would have to discover how to build bigger, stronger, and faster airplanes. Why they would have great sky battles, many airplanes all shooting at each other, some trying to shoot down the spy airplane and others defending it."

    "And then the day would come when a pilot and his assistant load an artillery shell into their airplane, fly to a target, and drop the shell onto it. It would be like having a cannon with a range of perhaps one hundred miles and no fixed position for the enemy to bombard in his own defense. Now imagine vast fleets of such airplanes swarming the skies, each airplane carrying more than one explosive shell."

    "They could attack cities and destroy them as General Sherman did with Atlanta, but far more rapidly! There would be no possibility of defense!"

    "No, I thought of that plan, too," he said. "But then I saw that the defenders could employ cannons firing grape shot. It would be like using giant shotguns to shoot down death-dealing ducks."

    "I can't begin to conceive the scale of the death and destruction attending such an affair," she said. "Surely they would have seen the futility of continuing such chaos!"

    "So we would like to believe," he said. "But I believe that even had the carnage been halted early in the war, the aftermath would have been a decline not seen since the end of the Roman Empire. The best that we might have hoped to see would have been a stall-mate that had left Europe divided against itself by a kind of iron wall."

    "A house divided against itself cannot stand," she said.

    "Our Lord was right about that," he said. "And I cannot think but that it would take at least a century for the world to recover the wealth and level of development that would have been lost in such a conflagration."

    "Percy, I declare that you have, indeed, conceived a thoroughly hideous vision."

    "Indeed so," he said. "This delirium had me convinced that I was on the verge of going completely mad."

    "What drew you back from the brink?" she asked.

    "The recollection that inscrutable Providence, in its infinite wisdom, saw fit to give us Babbage," he replied. He picked up his long-forgotten glass and raised it in salute. "May enlightened Humanity ever take as blessing the memory of Charles Babbage and his magnificent achievements!" He took a long sip from the glass.

    "And as we recall Christ as the Lord of Life, so let us remember Charles Babbage as the true Prince of Peace!" Naomi added and then drained her glass.

    The radio was playing "Aura Lea" sung by the popular crooner Elvis Presley, a song that he had first sung in the long-ago 1950's.

    "I like this so much better than his singing of 'O Sole Mio'," she said.

    "Yes," Percy agreed. "I believe that his Dixian accent mixes poorly with the Italian, though it well favors his crooning in English."

    "Oh!" she said after glancing at her watch. "It's almost time!"

    Percy looked up and saw that the sun had withdrawn its light from the city and that the city had responded with its own display of light. He picked up a control pod from the stand by his chair and pressed several small bumps on its surface. Curtains closed over the windows and their chairs turned slowly on their swivels. That wall that had been behind them lit up with an image.

    The ship stood on its launching pad, illuminated by searchlights that cut through the Florida night. Fluted pods connected to each other by flying buttresses made up the part of the ship that eyes could see. But the ship also had a structure that was not visible. A large digital clock in the foreground displayed the countdown.

    "Less than a minute now," the announcer said. "Less than a minute to the launch of Humanity's first space-ship propelled by the Schwarzschild effect. Less than a minute to the complete conquest of space. And ... five seconds ... four ... three ... two ... one ...."

    There was no bright burst of flame and its attendant roar of thunder. Instead the ship seemed to ripple, as if seen through water. It shimmered and the air around it glittered in all the colors of the spectrum. Slowly, majestically, the ship rose up off its pad and lifted itself into the sky. It gained speed at a rate no rocket could match, leaving a shining, slowly fading rainbow behind it, and vanished into the dark.


Recommended Additional Reading

Flynn, Michael F., "In the Country of the Blind, Part I", Analog Science Fiction/Science Fact, Vol. CVII, No. 10, Pages 10-69, October 1987.

Flynn, Michael F., "In the Country of the Blind, Part II", Analog Science Fiction/Science Fact, Vol.CVII, No. 11, Pages 136-182, November 1987.

    In this story Flynn describes a fictitious, highly secretive Babbage Society that manipulates history.

Swade, Doron D., "Redeeming Charles Babbage's Mechanical Computer", Scientific American, Vol. 268, Number 2, Pages 86-91, February 1993.

    This article reports on the 1991 construction of a part of Charles Babbage's Difference Engine as a means of testing whether it could have succeeded had its original construction been completed.


1. On our timeline Elvis Presley didn't sing "Aura Lea" or "O Sole Mio", but he did have two very popular songs related to them. "Love Me Tender" was based on the melody of the Civil War Era ballad "Aura Lea" and "It's Now or Never" was based on the melody of "O Sole Mio". On Naomi and Percival's timeline music evolved in a direction different from the path it followed on ours (klezmer-swing at the beginning of the 21st Century? Sure, why not?).

2. Franz Ferdinand (1863 Dec 18 B 1914 Jun 28) was an Archduke of Austria-Este, Prince Imperial of Austria and Royal Prince of Hungary and Bohemia, and from 1889 until his death, the presumed heir to the Austro-Hungarian throne. After he and his wife Sophie, Duchess of Hohenberg, were assassinated in Sarajevo by a Serbian anarchist, the government of Austria-Hungary made outrageous demands on Serbia, whose rejection of which led to a declaration of war. This led countries allied with Austria-Hungary (the Triple Alliance; originally comprising Britain, France and the Russian Empire) and countries allied with Serbia (the Triple Entente Powers; originally comprising Germany, the Austro-Hungarian Empire, and the Kingdom of Italy (which declined to join the fight)) to declare war on each other, starting World War I. Later The Ottoman Empire (Osmanli Imparatorlugu) joined the Triple Alliance along with the Kingdom of Bulgaria to form the Central Powers.

3. On our timeline Karl Schwarzschild (1873 Oct 09 B 1916 May 11) died in the course of World War I from a disease that he contracted at the front in Russia. He is best remembered for having devised the first exact solution of Einstein's field equations of General Relativity in the year before he died at age 42. We can't even imagine what he might have accomplished had he survived the war or had never gone to war at all. He died from infection attending pemphigus, an autoimmune blistering disease of the skin and mucous membranes that is as disgusting as it sounds and that tends to be more frequent than normal among Ashkenazi Jews. Had he been in a position to get proper treatment, he might have survived.


Back to Contents