In the first half of the 1800s, getting from one side of the United States to the other was a significant affair. There were no planes back then (of course), no cars, and the overland route via covered wagon was even more treacherous than the video games of our youth alluded to. In 1863, workers broke ground on the US transcontinental railroad. By 1869, one could ride from Nebraska to California in a week, instead of the six treacherous months previously required. It was one of the most remarkable feats of civil engineering – not to mention sheer labor – of the 19th century. Not only did the railroad unite the country with transportation, it also enabled a new era of communication: telegraph lines were installed next to the railroad, allowing messages to be sent instantly across the country.

One can imagine the number of calculations required to build a single trestle, let alone an entire 1780 miles of railroad. Only about 25% of the workers involved in the project were actually physical laborers doing the blasting, digging, and other heavy work. It is some of the other workers who would have most benefited from access to a difference engine.

For one, there is the obvious need for engineers to perform calculations regarding where it is most efficient to lay the route, how strong bridges must be to support the trains, how far it can be between refueling points without trains running out of coal and other supplies, and countless other mathematical problems. Indeed, any engineering project in that era would have benefited greatly from access to more accurate and varied tables of numbers.

A less immediately obvious, but undeniable application for a difference engine is all of the accountants and workers responsible for ensuring sufficient supplies. Given a certain number of expected miles of construction, how many railroad ties does one need to order? How much rail? When should you send the shipments of materials to optimize the number of trains you send, without losing valuable work time for lack of parts? Indeed, the benefit to accounting and management might have been greater than the advantages for the engineers.

Had the difference engine been available in 1863, would it have had any lasting impacts in the context of the railroad, or would it merely have eased the burden on overworked engineers and accountants? It’s hard to say. Even if use of a difference engine had made it cheaper to construct the railroad, it might not have been completed any sooner – the primary delays were caused by bad weather and treacherous conditions. Where the tables derived from a difference engine might have been more useful would have been for the hundreds of people starting new businesses in the recently opened up territories of the west. The railroad lead to a massive expansion of the population in the western US, and to be certain, many of them would have found the tables that a difference engine would have made available to be quite handy.

May 22, 1826 marks the first voyage of one of the most important ships in history, the HMS Beagle. The Beagle and the HMS Adventure departed together on a several-year long mission to Patagonia and Tierra del Fuego to conduct hydrographic survey, which involves measurement and description of the ocean and coastal regions. Like regular surveying, hydrographic surveying requires trigonometry and precise calculations. This task was difficult in the 19th century, especially on top of the challenge of navigation. The Straight of Magellan, off of the coast of Tierra del Fuego, is one of the most important but dangerous water passages in the world. In the weeks of surveying this especially difficult area, Captain Pringle Stokes went into a long phase of depression, ending in his suicide. He was replaced by Robert FitzRoy.

After his success on the first voyage, FitzRoy was put in charge of the Beagle’s second voyage, which departed in late 1831. On the first voyage, FitzRoy had wanted an expert on geology, so for the second, he decided to “endeavor to carry out a person qualified to examine the land; while the officers, and myself, would attend to hydrography”. He wanted a naturalist to go on land to learn about the geology. He had the additional requirement that the naturalist be someone that would make him a good companion. FitzRoy’s friend, Dr. John Henslow sent a letter to someone he thought might fulfill the position. The letter read,

“…that I consider you to be the best qualified person I know of who is likely to undertake such a situation— I state this not on the supposition of yr. being a finished Naturalist, but as amply qualified for collecting, observing, & noting any thing worthy to be noted in Natural History. Peacock has the appointment at his disposal & if he can not find a man willing to take the office, the opportunity will probably be lost— Capt. F. wants a man (I understand) more as a companion than a mere collector & would not take any one however good a Naturalist who was not recommended to him likewise as a gentleman. … there never was a finer chance for a man of zeal & spirit… Don’t put on any modest doubts or fears about your disqualifications for I assure you I think you are the very man they are in search of.”

The letter was to Charles Darwin. You know the rest of the story.

But what if Charles Babbage had completed his difference engine before all of this? He originally proposed his idea to the Royal Astronomical Society in 1822. Assume that everything ran smoothly and the invention was completed by 1828. The difference engine would have been able to quickly, cheaply, and accurately produce important trigonometric tables that would have been hugely beneficial to navigation and hydrographic surveying. In this case, the first voyage of the Beagle could have run much more efficiently and Captain Stokes could have enjoyed a relaxing trip to Tierra del Fuego instead of shooting himself in his cabin. Robert FitzRoy wouldn’t have taken over as captain so he wouldn’t have requested a naturalist/companion for his next voyage, and Darwin would not have been on board. He would have continued his plan of become a priest instead of writing one of the most influential works of all time.

So what if Darwin had never written “On the Origin of Species”? It’s fair to assume that the theory of evolution through natural selection would still have become scientifically accepted, since Darwin was not the first or only person to suggest it. However, Darwin was by far the most convincing, thorough, and methodically correct of the early proponents of evolution. “On the Origin of Species” laid important groundwork not only in evolution, but all life sciences, because of its strong use of the hypothetico-deductive method. Prior to this, naturalists would mostly just describe, name, and study the anatomy of species. Darwin used reasoning, analogy, and large amounts of evidence to form his “long argument”, which laid new foundations for the scientific method in biology. It was well-devised and argued strongly, making it an extremely persuasive work that inspired the evolutionary movement and exemplified proper scientific methodology. Without Darwin, natural selection would have been years behind, as would the foundations of biological research in general. This is perhaps what would have happened if Babbage had finished his machine and vastly improved the availability of accurate trig tables for celestial navigation and surveying.

But luckily Babbage never finished his engine…

Neptune was almost discovered by Galileo, but he mistook it for a star. Lalande, a French astronomer who created tables of the planetary positions also recorded Neptune’s position but also thought it was a star. One of the people responsible for discovering Uranus, John Herschel, also thought that it was a star. When Delambre was computing tables of Uranus, he discovered discrepancies in the position. He noted that there were discrepancies. During his time at Cambridge, John Couch Adam decided to begin investigating the irregularities of Uranus’ orbit. At relatively the same time, a French astronomer Urbain Jean Joseph Le Verrier also recognized the irregularities in the orbit of Uranus and thought this was due to an undiscovered planet. He then did computations based upon Newton’s gravitational laws and deduced the location of the undiscovered planet. Le Verrier gave his calculations to Johann Gottfried Galle who discovered the planet Uranus.

John Couch Adams

According to many stories, and as stated in Jacquard’s Loom, the reason why the planet was not discovered due to Adam’s calculations was because “[i]nstead of instigating a major telescopic search that would almost certainly have resulted in the discovery of the new planet, Neptune, Airy chose not to act on Adam’s information.” (104). Due to Airy overlooking Adam’s calculations, it was decided that Adams and Le Verrier needed equal credit in the discovery of Neptune. However, according to the Neptune file, found again in 1998, this is not the full story.

Urbain Le Verrier

In the file it is revealed that instead of being ignored by Airy, Adams was actually vague and inconsistent in his planetary position. Adam’s predictions ranged over 20 degrees of the sky, and after the planet was searched for during six-weeks at the Cambridge University Observatory was still not found. This was far different than Le Verrier’s calculations, which were one degree off of the actual planet’s location. Galle found the planet in half an hour. From Adam’s journal transcriptions, it shows “him still working on a problem which (one gathers) it was first necessary to solve in order to achieve a full solution.” (Kollerstrom, 5.42). After Galle’s discovery based on Le Verrier’s prediction, British astronomers contrived a selected story of events. Only Adam’s more accurate mathematical results were made public and made to appear as if Adam’s had the predicted the exact location of the planet. While Le Verrier protested at the time, it was in vain. He became very bitter about the lack of recognition for his work.

The God Neptune

If there was a difference machine to facilitate in Le Verrier’s calculations, I feel that he would have predicted the location of the planet quicker. While a difference machine would also help Adam, it was shown that his earlier calculations were more accurate than his later ones. For this reason I suspect that Adam’s predictions would have just become continually worse. From this, I feel that Le Verrier would be proven as the true discoverer of Neptune, and Adam would be recognized for his calculations and work to discover the location of the planet, but wouldn’t be considered a co-discoverer.

If it had not been for the lack of recognition of his discovery, I feel that Le Verrier would have been a more likeable person and wouldn’t have been so unpopular. This would have resulted in a more productive appointment as director of the Paris Observatory and probably would not have ended in him being overthrown and when later reinstated, stripped of most of his authority. This productive appointment would have led to more astronomical discoveries. This amount of astronomical discoveries would have caused Paris to be a center of astronomical discovery.

One such astronomical discovery, I feel, would have happened sooner is the discovery of Pluto. Since Le Verrier had already done work on the orbit of Neptune, I feel that if the orbit of Neptune would have continued to be tracked Le Verrier would have discovered perturbations in the orbit due to the planet Pluto. Such perturbations would have been linked through Newtonian orbital theory, which could have been further developed by Le Verrier if his view on Newtonian orbital theory had not been poisoned by his lack of recognition for the discovery of Neptune. Such an early discovery of Pluto would give it historical significance as a planet, and perhaps its planetary status would not have been taken away.

Sources:

Coimbra, Miguel. “Neptune – God of the Seas and Oceans.” Web. 12 Oct. 2011. <http://www.miguelcoimbra.com/images/gallery2.php?bimg=galerie/books/2romans/neptune.jpg&l=820&h=820>

Essinger, James. Jacquard’s Web. New York: Oxford University Press, 2002. Print.

Kollerstrom, Nicholas. “Recovering the Neptune Files.” RAS Research (2003): 5.23-5.24. Web. 12 Oct. 2011. <http://www.dioi.org/kn/neptunefile.pdf>

O’Connor, John, and Edmund Robertson. “Neptune and Pluto.” The MacTutor History of Mathematics archive. University of St Andrews. Sept. 1996. Web. 12 Oct. 2011. <http://www-history.mcs.st-and.ac.uk/HistTopics/Neptune_and_Pluto.html>

O’Connor, John, and Edmund Robertson. “Urbain Jean Joseph Le Verrier.” The MacTutor History of Mathematics archive. University of St Andrews. Dec. 1996. Web. 12 Oct. 2011. <http://www.gap-system.org/~history/Biographies/Le_Verrier.html>

“Portrait of John Couch Adams.” DSpace. University of Cambridge. 2008. Web. 12 Oct. 2011. <http://www.dspace.cam.ac.uk/handle/1810/214762>

Sheehan, William. “Secret Documents Rewrite the Discovery of Neptune.” Social Sky & Telescope: The Essential Magazine of Astronomy (2003): n. pag. Web. 12 Oct. 2011. <http://www.skyandtelescope.com/news/3307531.html>

“Urbain Le Verrier.” Random Knowledge. WordPress. 11 Mar. 2008. Web. 12 Oct 2011. <http://randomknowledge.wordpress.com/2008/03/11/urbain-le-verrier/>

William, David. “Neptune Fact Sheet”. Planetary Fact Sheets. NASA. Nov. 2010. Web. 12 Oct. 2011. <http://nssdc.gsfc.nasa.gov/planetary/factsheet/neptunefact.html>

      The historical event I have selected is the recovery of Lee’s Special Order 191 by a Union soldier during the American Civil War. The order detailed Lee’s intentions and how he was splitting his forces while invading Maryland and Pennsylvania. The order was intended to be destroyed (it was found wrapped around several cigars), but instead was found and relayed to George McClellan, commander of the Union Army of the Potomac. McClellan had previously been outmaneuvered and outfought by Lee’s Army of Northern Virginia multiple times. However, with this order he was able to predict Lee’s movements, and forestalled the invasion of the North at the Battle of Antietam. Many historians believe that McClellen, a notoriously over-cautious and slow-moving general, could have taken greater advantage of the order. Antietam was a very bloody battle, with heavy casualties on both sides. Lee’s army did retreat, but McClellan, fearing a trap, refused to pursue, despite the insistence of President Lincoln. Hindsight shows that if he had pressed his advantage, the Army of Northern Virginia was not in good shape, and could have been destroyed or severely damaged. A few days later, Lincoln removed McClellan from command for failing to take full advantage of his intelligence.
However, the Battle of Antietam did allow Lincoln to make the Emancipation Proclamation. This was crucial, because the President’s advisors had convinced him to delay the announcement until after a Union victory, so as to not seem like a move of desperation. The result of the Emancipation Proclamation was that France and Britain could not convincingly recognize the Confederacy as a legitimate nation, due to slavery now being a central issue of the war.
Harry Turtledove, the foremost contemporary alternate history author, used Special Order 191 as the point of divergence for his epic alternate history series Southern Victory, where the pertinent copy of Special Order 191 is in fact destroyed. I would propose a similar change as part of a ripple effect from Babbage’s Difference Engines becoming widespread and well-used.
Had Difference Engines been finished, used, and proved helpful enough for common use, the technology of the period leading up to 1860 could have been wildly affected. Babbage would have continued to be prominent, and it seems reasonable to assume that this other ideas, inventions and interests would have become more important among the scientists and engineers of his day. In addition to that, if the Difference Engine succeeded, it’s likely that other mechnical computation devices would have been invented in a similar sense to the electro-mechanical devices that began to flourish after Hollerith’s initial success in the 1890s.
One field that would have been the key beneficiary of these advances would have been cryptography. By World War I, military cryptography was commonplace; however, Special Order 191 was not encrypted, which allowed the Union army to quickly realize its importance, forward it up the chain of command, and understand it. Had cryptography spread to the Confederacy’s armed forces, it would have at the very least taken the Union some time to decrypt the order, were it even realized as important at all by the corporal who found it.
In actual history, McClellan’s deficiencies as a commander were such that even with fantastic military intelligence, he was only able to fight Lee to a standstill, barely enough of a success to allow the Emancipation Proclamation to go out. Without Special Order 191 in hand, it seems more than likely that Lee would have once again humiliated Union armed forces, this time on their own soil, and possibly given the Confederacy enough of an advantage to win the war. Had the CSA’s advantage after Lee’s Maryland campaign been seen as sufficient, Britain and France would likely have recognized the South and broken the blockade to restore the flow of cotton exports and to hurt the USA.
Such a vast change in the power balance on the American continent would have had vast consequences. Certainly, Britain and France would have been enemies of the United States, rather than eventual allies, due to their effective alliance with the CSA. Furthermore, assuming German unification proceeded as in actual history, the USA and Germany could well have applied the principle of “the enemy of my enemy is my friend”, and found common ground in the later 1800s, maybe even in World War I. Had the United States never entered World War I against the Central Powers, but rather been tied down by a war at home (or at least the prospect of being counterbalanced by the Confederate States), the entire 20th century would look completely different. Everything from German backlash to the Treaty of Versailles and the dismantling of the Ottoman Empire to the October Revolution in Russia could have had vastly different outcomes, with a German-Union alliance, and an independent Confederate States of America.
The farther one moves forward from Special Order 191, the greater the implications become. With simple knowledge of encryption, and perhaps even something as simple as a substitution or rotation cipher, the importance of Special Order 191 or at least its meaning would have never been realized (or at least not soon enough). That paper, wrapped around cigars, is one of the hinges upon which history has turned, and with the technological advances that could have been perpetrated by the Difference Engine, history could have turned in a very different direction.