Book Review
Measure of the Earth – The
Enlightenment Expedition that Reshaped the World
I picked this book up in Ireland a few years ago, at Charlie
Byrne’s used bookshop in Galway. I read it then, and I reread it recently – mostly
because it’s a rollicking good read, but also because it is such an astonishing
academic achievement. An American, author Larrie Ferreiro completed his Ph.D.
at Imperial College London in 2004.
Since ancient times, intellectuals had
known that the planet was essentially spherical. However, in the 18th century
debate began to rage over whether it might bulge at the equator or be somewhat
elongated at the poles. There were two possibilities. One was that the world
was like an exercise ball with someone sitting on it was one perspective. The
other was that the planet was a bit like an egg standing upright in its carton.
While Europeans had long known the
shape of the earth, they had yet to catalog its exact dimensions. Also, there
were disputes about its shape. That is the reality of the book’s full title: Measure of the Earth: The Enlightenment Expedition that Reshaped the World. Fundamentally,
this work is about an Enlightenment-era scientific mission designed to settle
an academic debate regarding the shape of the world. On one side were the
defenders of René Descartes; on the other, those of Isaac Newton. Descartes
believed the Earth was elongated at the poles, giving it an egg-like shape. Newton
thought the spin of the earth caused it to bulge at the equator and flatten at
the poles.
Isaac Newton had argued for a
bulging equator – an idea consistent with his revolutionary theories about
gravitation. From today’s perspective, the controversy may seem trivial or even
nationalistic: just another quarrel among philosophers and scientists over a
trifle, or one of the endless quarrels between France and Britain over almost
anything.
Yet without knowing the shape of
the Earth in some detail, you couldn’t reliably determine geographical
location. Navies couldn’t navigate with precision, land surveyors would be a
bit off in their calculations, and explorers might go astray.
Ferreiro brings us into the halls
of the French Academy of Sciences where careers were made, and lost, over this
debate. But, this was not merely a dry academic question. While the men of letters
at the French Academy and the British Royal Society could overlook political
differences in the name of science, government and military officials were well
aware that the shape of the earth was of grave importance – so much so that,
the French mission was giving funding and support by Comte de Maurepas, King Louis
XV’s minister of the navy and minister of colonies.
Maurepas well understood the advantages
that would come with an accurate measurement of Earth: It might give France the
scientific advantage necessary to unseat Britain’s sea power. It is no surprise
that at the same time the British were offering £20,000 to whoever could claim
the “Longitude Prize” and enable an accurate measurement of longitude at sea. Measure
of the Earth helps to illustrate these and other connections between science
and the politics of the day.
To resolve matters, the French and
Spanish joined forces in the first international scientific expedition. A team
sympathetic to Newton’s view would measure the exact length of a degree of
latitude near the equator. This would then be compared with the same
measurement taken in France. If the latter was larger, Newton was right.
Ferreiro has produced an
astonishingly detailed account of the so-called Geodesic Mission and its
importance. He has mined all the sources, visited the key sites, balanced
conflicting historical documents and memoires, and produced a book that is
gripping, authoritative and balanced. He describes this expedition — despite
the frequent foolishness and ineptitude of its members — as one of the great
scientific adventure stories of the 18th and early 19th centuries.
It “inaugurated a spate of
large-scale international scientific expeditions that rewrote our understanding
of the planet,” he said. “It gave us the concept of South America as a unique
place, separate from its mother country of Spain, which would eventually give
birth to the new nations of Latin America.” His footnotes reference works in
French, Spanish and English. To write the book, the author went to every place visited
by the original team members – both in France and Spain and in Latin America.
The 1735 Geodesic Mission to the equator
mainly consisted of three mismatched French savants and a pair of Spanish naval
officers. Gathering together everything that can be known about the mission,
Ferreiro shows how the ideals of science may even be realized by flawed human
beings – in this case, a team who took nearly a decade to complete a project
that shouldn’t have needed more than three years.
The mission leader was the
ambitious Louis Godin, who lacked every possible management skill. He was
arrogant and absolutist, kept crucial information to himself and spent the
expedition’s government money with abandon – a good deal of it on a prostitute with
whom he’d grown infatuated. (Godin spent the equivalent of US$27,000 of the
expedition’s funds on a diamond for his lover.) These serve to highlight the
quite eccentric cast of characters who were tasked with such an important
mission.
Another Frenchman was the polar
opposite. Charles-Marie de La Condamine was a worldly and wealthy friend of Voltaire,
as much an adventurer as a scientist and one of those men whose actions
regularly combined “curiosity, bravery, and sheer idiocy.” Because of Godin’s
squandering, La Condamine ended up using his personal wealth to fund much of
the expedition. A third Frenchman, Pierre Bouguer, had not really wanted to
join the expedition in the first place. Eventually, he became its de facto chief.
After months of difficulties and
delays on the island of Santa Domingo, the French group was joined by two
Spanish naval officers: Jorge Juan y Santacilia and Antonio de Ulloa y de la
Torre-Guiral. Ferreiro clearly admires these young men for their quiet
professionalism. They were capable engineers, expert swordsmen, deeply
sympathetic to the native peoples and openly outraged by colonial atrocities.
The two friends would eventually go on to distinguished maritime and diplomatic
careers, and are still venerated by the Spanish navy. Wince 1851, Spain has
named three pairs of warships after them.
Eventually, the full team reached
its destination, the city of Quito. Following further squabbles and reversals,
the scientists, along with their servants and slaves, finally began their
measurements. They first created a baseline, “an absolutely straight path,
seven miles long and just eighteen inches wide.” Then, on the slopes of the
nearby mountains and volcanoes of the Andes, they erected “large pyramids of
timber, straw, and fabric, whitewashed with lime and lye, to make signals that
could be clearly seen through a telescope, even at thirty miles’ distance.”
Using these pyramids — and sometimes just their large tents — as focal points,
they gradually calculated the dimensions of a chain of gigantic interlocking
triangles running south along the Andes. This triangulation reached slightly
more than 200 miles to the city of Cuenca.
Nothing went smoothly. Frequent
cloud cover impaired accuracy during key sightings. The group suffered from
altitude sickness, dysentery and malaria (the latter cured by quinine from the
cinchona tree, which the scientists studied), hostile colonial administrators,
lack of funding and internal strife. At one point, a riot erupted at a local
bullfight. The expedition’s surgeon, Jean Seniergues also became involved in a
lover’s quarrel. He was beaten and stabbed after helping cause a riot at a
bullfight in the town of Cuenca, and died of his wounds.
After war broke out between England
and Spain, and British naval forces ravaged the nearby seaports, the two
Spaniards were ordered to provide military leadership and assistance. Despite
such complications, the team eventually completed its setup and, using an
instrument called a sector, made a series of simultaneous celestial
observations and calculations. These determined that the length of a degree of
latitude at the equator was 68.7 miles. This, Ferreiro says, is “within fifty
yards of the modern accepted value.” The result proved that “the length of a
degree of latitude shortened considerably toward the equator, as a result of its
bulging out from the axis.” The expedition had confirmed that the planet was an
“oblate spheroid,” and that Newton was right.
You may have wondered why, when we
fly from Western Canada to Europe, the flight goes to higher latitudes, and we can
usually look down into Greenland. The reason is that the planet is an oblate
spheroid. Because that is so, the flight is shorter if we take a northerly
route.
When the pair eventually returned
to France, both were fêted by their scientific colleagues. La Condamine’s
action-packed “Abridged Relation of a Voyage Made in the Interior of South
America” soon became an international bestseller. Bouguer read his memoirs of
the expedition to the French Academy of Sciences and to other audiences over
the next seven months. This account – it was a bit “self-serving,” Ferreiro wrote,
“a narrative of arduous toil under grueling conditions in the noble cause of
science” – essentially became the official account of the Geodesic Mission.”
"By publishing less
scientific, more popular accounts of the Geodesic Mission's exploits,"
Ferreiro wrote, "La Condamine was also pulling back the curtain on the
previously veiled kingdom of Peru. Plays, operas, bellies and novels featuring
Aztec and Peruvian themes began sprouting up….At the same time that he was
transforming the expedition's travels into a thrilling narrative adventure, he
devoted considerable effort to producing a comprehensive atlas of the audience
you of Quito….The finished Atlas was released to public acclaim, coming at a
time when European society was transfixed by all things Peruvian."
La Condamine's published works were
so successful, I think, because he was a born writer, as Ferreiro illustrates
by quoting a passage from his field notes.
The higher I climbed the more the
jungle cleared; soon I saw only sand, and higher up naked and calcified
boulders which bordered the northern edge of the volcano of Pichincha. Having
reached the highest point of the edge I was seized by a sense of wonder mixed
with admiration, and the appearance of a large valley five to six leagues wide,
interspersed with streams which joined together: I saw, as far as my I could
see, cultivated lands, divided between planes and prairies, green spaces,
villages, and towns surrounded by hedges and gardens: the city of Quito,
far-off, was at the end of this beautiful view. I felt as if I had been
transported to the most beautiful of provinces in France, and as I descended I
felt the imperceptible change in climate going from extreme cold to the temperature
of the most useful days in May. Each instance I added to my surprise; I saw,
for the first time, flowers, but send fruit in the middle of the countryside on
all of the trees. I so people planting, laboring and harvesting all on the same
date and in the same place. I have let myself become carried away by the memory
of the first impression I had been, quite forgetting that this [Journal]'s is
only a place for recounting our academic work.
Godin – the man who invested so
much of the mission’s money on a prostitute – knew he had ruined his career and
stayed behind when the rest of the mission began heading home. Later, after a
huge earthquake and an accompanying tsunami, he partially redeemed himself by
overseeing the reconstruction of Lima. In this work, he greatly benefited from
his experience as a surveyor. According to Ferreiro, under his guidance "Lima
was transformed into one of the most gracious cities in South America.… The
city's architecture also became more modern and secular, with churches and
monasteries giving way to civic buildings like theaters, and with prayer rooms
in private homes being converted to French-style salons."
Ferreiro combines exciting
narrative with good science, including clear descriptions of triangulation
surveying. Personally, I felt both educated and entertained. While the debate
had largely pitted French and English scholars against one another, it was a
sign of the growth of a scientific mindset how readily the findings of the
mission, which proved Newton correct, was readily accepted. The Geodesic
mission to Peru was just the beginning of greater cooperation among scientists
to form a more accurate measure of the earth. The end result of this process
would be a command from the French National Constituent Assembly to form a new
set of measurements to replace those used by the old regime. What they decided,
based around a “metre” or one-ten-millionth of the distance between the North
Pole and the Equator, would become the basis of the metric system.
Thus, the “winner” of the
scientific debate fades from the narrative in the same way it did in reality. Besides
recounting the legacy of this extraordinary mission, Measure of the Earth documents the intersections between this
mission and the science, intellectual ferment, politics, and culture of the Enlightenment
itself.
To sum up, Measure of the Earth documents the first international scientific
expedition to measure a degree of latitude at the equator. In doing so, he
recounts not only a scientific adventure filled with eccentric personalities
but a mission that intersects with the politics, culture, and intellectual mood
of the time. One of the outcomes of this work is ironic. So famous was this
scientific expedition that, after its rebellion against Spain and nearly a
century of ultimately successful nation building, the country itself República
del Ecuador, which translates as the “Republic of the Equator.”
