In the 1994 novel The Island of the Day Before by Umberto Eco, a modern editor studied fragmented manuscripts of uncertain origin (possibly recovered by Abel Tasman in his 1642 expedition of the South Pacific) and attempted to reconstruct the history of a 17th century Italian nobleman stranded on a mysterious deserted ship. The nobleman was likely a spy of Cardinal Mazarin — and, remarkably, may have spotted a quokka on what is now Rottnest Island, Western Australia, decades before the Dutch explorer Willem de Vlamingh made landfall there.

The other novel is Mason & Dixon, published in the same decade. In it, a clergyman of questionable denomination was stranded at his sister’s house in 18th-century Philadelphia over Christmas and resorted to telling tall tales to entertain the unruly children — and occasionally the adults. He did this by recounting the history of the two British astronomers who charted the boundary between Pennsylvania and Maryland in colonial America. The good Father might or might not have been a member of Mason and Dixon’s legendary 1763–1767 expedition and most certainly had fabricated a lot of his stories.

The Island of the Day Before and Mason & Dixon are both encyclopedic novels with a lot to say about a wide range of esoteric subjects, but a thread runs through both — the complex relationship between theoretical sciences and their practical applications. In particular, in the background of both novels is the hundreds of years’ history of European scientists’ attempts to solve the Longitude Problem. It’s an interesting coincidence (?) that in the same decade, Dava Sobel published a popular nonfiction book on this subject. What was it about the 1990s that sparked such interest in longitude?

In this post, I will summarise the historical and conceptual background of some of the topics shared by the two novels.

The romance of observational astronomy 🔗

There is a romantic and visceral excitement associated with stargazing. The technical complexity, however, seems to have deterred novelists from depicting it in literature. What I find so interesting about the two novels is that they go into loving details about the intricate apparatus and procedures used in early modern science, and both manage to capture the magic of reading the night sky.

In The Island of the Day Before, the protagonist assisted an eccentric Jesuit Father¹ in an observation of the eclipse of Jupiter’s moons — about 30 years after their discovery by Galileo Galilei. Galileo himself had invented an instrument called Celatone for making precise measurements of these events, but the apparatus used by this Jesuit in the novel was a Rube Goldberg contraption that reads like a parody of the complicated machines of the Baroque era. The observer wears Galileo’s Celatone — a headpiece with a telescope protruding from it — while sitting in a chair floating in a tub of oil. The assistant uses a clock and a pendulum-driven gizmo to record the time of eclipse at the resolution of seconds. Stability is the key here: the purpose of the oil tub is to keep the observer stationary at sea. But of course, this primitive suspension system was not practical in reality. Just as the Father saw one of Jupiter’s moons disappearing into the shadow of the planet, he lost balance, soaked himself in oil and shattered the telescope. What’s the purpose of this observation? It’s all about longitude. We’ll learn more about it in the next section.

In Mason & Dixon, entire chapters are devoted to the observation of the transit of Venus — a rare astronomical event where a black disk (Venus) is seen moving across the sun. Early in the 18th century, Edmund Halley pointed out that the observed duration of the transit was dependent on the latitude of the observer. He reasoned that if astronomers across the globe recorded the same transit, the data could be used to accurately estimate the distance between the Earth and the Sun — and from that, the scale of the entire solar system. This was why the Royal Society sent Mason and Dixon to the Cape of Good Hope in South Africa (then a Dutch colony) to observe the 1761 transit of Venus. It was their first adventure together. Although Mason and Dixon successfully accomplished their mission, other astronomers who participated in this project encountered numerous problems, and the measurement had to be repeated 8 years later — after Mason and Dixon’s land survey in America. The two astronomers did not observe the 1769 transit together — Mason went to Ireland while Dixon observed from Norway — and their diverging paths in those years became the backbone of later chapters of Pynchon’s novel.

The events described in the two novels are separated by more than 100 years. What a difference this century makes! The publication of Principia Mathematica by Isaac Newton established the theoretical foundation of astronomy, heliocentrism became widely accepted by European scientists, and scientific instruments became much more sophisticated. Compared to the primitive telescopes described in The Island of the Day Before, the telescopes that Mason and Dixon brought to South Africa were cutting-edge. They were equipped with John Dollond’s achromatic lens, which significantly improved the optics. The development of the achromatic lens was in turn made possible by James Bradley (the Astronomer Royal and a major character in the novel), whose discovery of the aberration of light gave opticians the precise measurements they needed to correct for chromatic distortion.

The transit of Venus is not the only significant astronomical event described in Pynchon’s novel. It also alludes to the observation of a solar eclipse by ancient Chinese astronomers and the discovery of Uranus by William Herschel in 1781.

The quest for longitude 🔗

Measuring a ship’s location at sea was essential for navigation, and by the early modern colonial era (the time of Eco’s novel), it became obvious that it was the key to immense wealth and power. However, it would take more than a hundred years to solve the Longitude Problem. To appreciate the difficulty, consider the simpler of the two spherical coordinates that define a position on Earth: latitude — the angular distance north or south of the equator. The ancient Greeks already knew that the highest point of the Sun in the sky on the same day is different at different latitudes. Measuring the latitude is therefore just a matter of measuring angles in the sky. Sailors did it routinely with reasonable accuracy in the 17th century.

The longitude (the angular distance east or west of a reference line), however, is entirely different. At two locations on the same latitude but different longitudes, the Sun reaches the same maximum elevation on a given day — but it reaches that point at different local times. The problem of longitude is therefore centred on knowing the local time of the same astronomical event at different locations. Soon after Galileo discovered the moons of Jupiter, he realised that their eclipses (which happen every couple of days) could be used to synchronise the observers, but, alas!, the idea was not practical at sea in the early 17th century.

At a time when the scientific method had not been firmly established, some of the attempts seem lunatic to modern readers. A major plot in Eco’s novel is that the protagonist was forced by France’s minister Cardinal Mazarin to spy on England’s secret solution to the Longitude Problem. Aboard a ship in the South Pacific, he discovered that England’s secret was a wounded dog hidden in the ship. Based on the pseudo-scientific belief in a telepathic link between a flesh wound and the weapon that caused the wound, the idea was that the dog, who was cut by a knife at London prior to the voyage, could be made to cry remotely from London by applying a powder to the knife ². If the actions at London were taken daily at a fixed hour, the local time when the dog cried determined the longitude. This wounded-dog “solution” is amusing enough to be mentioned in Sobel’s nonfiction book, but it should be noted that the idea originated in an anonymous pamphlet written to mock the pseudo-scientific belief in sympathetic actions. It was never a serious proposal ³.

The rising rivalry among European naval powers in the 17th century contributed to the institutionalisation of astronomy. Jean-Baptiste Colbert — the young administrator in Louis XIV’s court and a character in The Island of the Day Before — went on to fund the Paris Observatory. Great Britain followed with the establishment of the Royal Observatory in Greenwich in 1675. That brings us to Mason & Dixon. Charles Mason’s career started with his stint as the assistant of James Bradley, the third Astronomer Royal of the Royal Observatory. The death of Bradley in 1762 was one of the factors which prompted Mason to accept the survey work in America (more on this topic in the next section).

After the transit of Venus, Mason and Dixon sailed to the island of Saint Helena to rendezvous with the British astronomer Nevil Maskelyne — who was described as a manic and deeply disturbed person in the novel. Maskelyne had been stationed at Saint Helena ostensibly on the same mission as Mason and Dixon, but his real agenda was a trial run for an alternative solution to the Longitude Problem. That’s right — it’s more than 100 years after the events in Island of the Day Before, and scientists were still after longitude! But they were close to the end of this quest.

You see, James Bradley, Charles Mason, Nevil Maskelyne, along with other astronomers in the Royal Society were Lunarians — Pynchon’s term for devotees of the lunar distance method. This approach sought to use the angular distances between the moon and a set of reference stars to determine longitude. The concept originated in the 17th century, but it only became practical after Maskelyne was appointed Astronomer Royal (in the novel, Mason read about his appointment bitterly in America). The lunar distance method was successfully used in naval navigation for a period of time, but as Mason assisted Maskelyne in its development, he already knew that the accurate marine clocks built by the British carpenter John Harrison would soon become the actual solution to the Longitude Problem. If you could carry with you a clock that told you the Greenwich time at any moment, there would be no need for tedious astronomy-based methods. Dava Sobel’s nonfiction book goes into great details about the rivalry between Nevil Maskelyne and John Harrison.

The mystery of time 🔗

How can the measurement of space be solved by the measurement of time? Both novelists were clearly struck by how mysterious this unintuitive idea is.

Latitudes are measured relative to the equator — a unique line dictated by the physical properties of Earth. The reference line for longitude, on the other hand, is arbitrary, and indeed, European cartographers set the prime meridian (the zero-degree longitudinal line) to several locations — from the Canary Islands, to Paris and Rome — until it was standardised at Greenwich in the 19th century. The arbitrariness was uncomfortable to the mystic Jesuit character in The Island of the Day Before, which prompted him to determine a theologically-justified absolute prime meridian. It followed that the line exactly 180° away from that absolute meridian would mark the boundary between one calendar day and the next — where today meets yesterday. One only has to walk (or swim) across this invisible line to travel in time…

To modern readers, that is obviously confusing the measurement of a physical quantity with physical reality it measures, but the novel was set in an age where the boundary between mysticism and science was uncertain.

Fast-forward to the days of Mason & Dixon, and the nature of time continues to mystify. Great Britain adopted the Gregorian Calendar in 1752 (only 170 years after it was introduced!) which required 11 days to be “skipped” to catch up with the Gregorian date. In the novel, Mason encountered, in a bar in London, an angry crowd who believed that the Astronomer Royal James Bradley was responsible for “stealing” 11 days from the hard-working people.

The map is not the territory 🔗

The image above is the 1648 world map Nova et Accuratissima Terrarum Orbis Tabula by Dutch cartographer Joan Blaeu. In the age of GPS and Google Earth, it’s difficult for us to imagine a time when the geography of the world was so uncertain: the shapes of the continents were imprecise, California was depicted as an island, and the Southern Hemisphere was mostly uncharted. A major character in The Island of the Day Before was on a quest to find the mythical Island of Solomon in the South Pacific, which was believed to be first identified by the Spanish explorer Álvaro de Mendaña in the 16th century ⁴.

However, the uncertainty would be gradually reduced by scientific measurements. Umberto Eco’s novel mentioned that Jesuit missionaries (e.g., Giulio Alenio and Charles Spinola) recorded the hours of the 1612 lunar eclipse at different locations, and used the data to estimate the relative longitude of Macau and Nagasaki, thus improving the mapping of Asia.

After a century, Jesuits like Christopher Maire — who appears as a character in Mason & Dixon — continued the measurement of Earth at a much greater level of precision. His measurement of 1 degree of latitude with Roger Boscovich in 1750 indicated that the Earth is shaped like an oblate spheroid, as predicted by Newton. The later chapters in Pynchon’s novel deal with Charles Mason’s participation in the Schiehallion experiment, which proved that the gravitational pull of a sufficiently large mountain could deflect a plumb line enough to skew the measurements! These experiments testify the remarkable degree of precision of 18th century science.

These experiments were not merely beautiful confirmations of Newton’s theory. They also had significant implications in cartography and navigation. The survey of the Mason–Dixon line — the main attraction of Pynchon’s novel — was the application of cutting-edge astronomy to the mundane problem of land disputes among British colonies in North America.

Around the time of The Island of the Day Before, British kings defined the boundaries of American colonies in land grant charters in terms of latitude, rather than natural landmarks. The problem was that American maps in those days were quite inaccurate, leading to contradictory interpretations and a century of disputes and violence. Mason and Dixon were commissioned by colonial governors to sort out this mess. Contrary to popular belief, they were not rugged land surveyors who lived in the wilderness. Rather, they were astronomers experienced in high-precision measurements, who spent lots of time in their 1763–1767 expedition living in cities, making astronomical observations with advanced instruments not available in America, doing calculations, and even writing scientific papers!

There is probably no other scientific project dramatized in more loving detail in literature than the survey of the Mason–Dixon line. In Chapter 33 of Mason & Dixon, for example, we are treated to a poetic (and humorous) depiction of how the two astronomers used the trajectory of stars to determine latitude ⁵. The relic of the temporary observatory that was used, the Star Gazers’ Stone, is still visible today.

Strange and beautiful machines 🔗

... the idea of a beautiful machine is a fairly recent one and it might be said that we became vaguely aware of this around the seventeenth century ...

— Umberto Eco (ed.), History of Beauty, 2004

Umberto Eco and Thomas Pynchon wrote obsessively about optics and clockwork. Pynchon would carry the optics theme in Mason & Dixon forward to his next novel Against the Day (2006), where he went into great depth about double refraction and the measurement of the speed of light. Eco made a scientific instrument the central image of his novel Foucault’s Pendulum (1988) and incorporated a 14th century eyepiece into the plot of The Name of the Rose (1980). But there are many more wondrous machines in the two novels.

The Jesuit scholar Athanasius Kircher (1602–1680) was a representative thinker of the Baroque age. For modern readers living in an age where knowledge has become extremely specialised, his prodigious curiosity about every topic imaginable seems almost absurd. In The Island of the Day Before, the protagonist encountered elaborately constructed machines that Kircher wrote about: water-powered automata that played music, a magic lantern that projected color images, and … the Specula Melitensis Encyclica — “an animated book capable of revealing all the mysteries of the Universe” ⁶. It’s described as a machine consisting of a cube and a pyramid, whose faces can perform calculations, display calendars, predict astronomical events, and illustrate concepts in medicine (among many other things). The machine in the novel is said to have a built-in world clock, which by definition solves the Longitude Problem. That part is fictional.

Another impractical machine in the novel is the Aristotelian Machine, which is a mechanical embodiment of The Aristotelian Telescope concept envisioned by the Italian scholar Emanuele Tesauro. Instead of a telescope for viewing stars, it’s an instrument for experimenting with concepts and metaphors. In other words, it’s a philosopher’s and writer’s machine. With the turn of a crank, 3 rotating cylinders generate random combinations of Aristotelian categories to produce metaphors such as “dwarf = atom of man”. It’s one of the many Quixotic systems for formalizing concepts and language in the 17th century ⁷.

Benjamin Franklin is a major character in Mason & Dixon. In the novel, the first time they met, Franklin invited the astronomers to a Glass Armonica recital. The unusual instrument, invented by Franklin himself, is a series of rotating glass bowls, which make otherworldly sounds when touched by wetted fingers ⁸. This invention is obscure today, but it was a sensation in Europe soon after it was invented. Marianne Davies, who made an appearance in the novel, was the first virtuoso of the Glass Armonica and toured Europe with this instrument.

According to Pynchon, a “member” of Mason and Dixon’s party was a mechanical duck, whose antics provide comedic relief throughout the narrative about the Mason-Dixon line survey. The Duck is based on the Digesting Duck automata constructed by the French inventor Jacques de Vaucanson ⁹. Why is one of the most well-known robots in history a duck that defecates? That seems hard to comprehend from the modern point of view, but the life-like movements of Vaucanson’s duck shows that the art and science of automata had progressed tremendously since Kircher.

Of the origin of novels 🔗

... Who claims Truth, Truth abandons. History is hir'd, or coerc'd, only in Interests that must ever prove base. She is too innocent, to be left within the reach of anyone in Power, [...] She needs rather to be tended lovingly and honorably by fabulists and counterfeiters, Ballad-Mongers and Cranks of ev'ry Radius, Masters of Disguise to provide her the Costume, Toilette, and Bearing, and Speech nimble enough to keep her beyond the Desire, or even the Curiosity, of Government...

— Thomas Pynchon, Mason & Dixon

The quote above, which appears to be written to justify the fabulist approach of Mason & Dixon, was spoken by one of the characters in a heated debate about the nature of Truth. He was immediately rebutted, so no, it is not a manifesto. It’s merely one of the points of view that one might want to entertain.

In the colophon of The Island of the Day Before, we have

...Finally, if from this story I wanted to produce a novel, I would demonstrate once again that it is impossible to write except by making of palimpsest of a rediscovered manuscript - without ever succeeding in eluding the Anxiety of Influence. Nor could I elude the childish curiosity of the reader, who would want to know if Roberto really wrote the pages on which I have dwelt far too long. In all honesty, I would have to reply that it is not impossible that someone else wrote them, someone who wanted only to pretend to tell the truth. And thus I would lose all the effect of the novel: where, yes, you pretend to tell true things, but you must not admit seriously that you are pretending.

— Umberto Eco, The Island of the Day Before

This was meant to be written by a modern editor who pieced together the narrative from discovered manuscripts. So, not from the mouth of Umberto Eco either.

The stories of both novels are told in nested frame narratives that question themselves. Both call attention to the act of story telling: In The Island of the Day Before, some chapters are presented as a novel written by the protagonist himself. In Mason & Dixon, the storyteller freely borrowed plots from the audience’s favorite pulp fiction to retain their attention.

Of course, these are the traits of postmodern literature. What makes them especially interesting here is that the same story of longitude is also told in Dava Sobel’s nonfiction book Longitude, giving readers the option to read it straight. And perhaps, reading it straight, they will notice that even a nonfiction account is shaped by its storyteller.