In response to a pointer from Earl F. Burkholder I recently read an interesting book with the eye-catching title of: The Mapmaker’s Wife, subtitled A true Tale of Love, Murder, and Survival in the Amazon (*). The heading is somewhat misleading, for the tale of Isabel Gramesón-Godin, the "mapmaker’s" wife, is interwoven with the history of a major geodetic survey, in which her husband had only a minor role and with which she had nothing to do whatever. The book is really a history of the 1735 French expedition to what is today the South-American country of Ecuador, organized by the French Academy of Sciences for the purpose of measuring the length of a one-degree meridian at the equator.
The argument to be settled concerned among others the precise size and shape of the earth, a question that at the turn of the 18th century had blossomed into an English-French rivalry of scientific thought with plenty of chauvinistic undertones. The English favored the opinion of their renowned Sir Isaac Newton, who had investigated the force of gravity and written in his Principia, that the earth bulged at the equator, citing centrifugal forces created by the earth’s rotation. This ran counter to French scientific opinion about the nature of the universe, including the assumption that the earth was a "spheroid prolonged toward the poles". It was of course not entirely as simple as that, and author Robert Whitaker describes the different theories at some length.
The shape of the earth was only a part of the arguments; an additional unknown was its exact size. Measurements of a sort had been made since antiquity, when in about 235 B.C. the Greek scholar Eratosthenes of Alexandria measured the shadow the sun cast on the day of the summer solstice. It had been reported to him that on the same day the sun would shine vertically into the bottom of a well in the town of Syene, located roughly 450 miles to the south. Eratosthenes was lucky in that his errors almost cancelled each other out, and his reported circumference of the earth was within less than a thousand miles of the true figure (too small). Others followed with their own measurement problems, including in 1525 a French physician who measured the lengths of what he thought was one degree of latitude by counting the revolutions of his coach wheel.
To settle the argument once and for all the French Academy of Sciences assembled a group of savants and sent them to the Viceroyalty of Peru to measure the length of a degree of latitude at the equator, to be later compared with the measured lengths of a degree in France and in Lapland. Arrangements had been made with the Spanish Crown to visit the jealously guarded colony, closed to all foreigners, but problems remained and were to plague the members of the expedition to the end.
The surveyors left France in May 1735, but political, bureaucratic and financial problems caused many delays, and it was not until May 1736 that they arrived in Quito where the streets were lined with people who had never seen a foreigner before. Social courtesies caused further delays und it was September by the time the survey got underway. They had decided to measure both, a degree of latitude as well as one of longitude and started by laying out a baseline for their proposed triangulation. Measuring was done by two groups of surveyors starting at opposite ends, each employing three twenty-foot-long wooden rods laid end to end with extreme care, and compared daily against an iron toise (6.39 English feet), until the entire length of the baseline of 6,272.656 toises (about 7 1/2 miles) had been measured twice, the two measurements agreeing within three inches of each other.
Author Whitaker describes in detail the hardships caused by the unfamiliar terrain and the horrible weather in the extreme altitude of the Andes, an altitude that rose to 15,413 feet on Mount Pichincha were they started their triangulation in August 1737. On many peaks they measured altitude with a barometer and made experiments with a pendulum clock to determine the lengths of a one second pendulum under different gravitational conditions. Because France had failed to provide adequate funding much time was lost arranging for personal loans in the cash-strapped colonial society, time that some members of the group spent collecting botanical specimen and trying to learn Quechua, the language of the local Indians (Incas), some of which were employed as guides and packers in the survey. In addition, the toll their work took on their health made lengthy rest periods in the relative comfort of the few cities necessary.
Measurements, check-measurements, astronomical observations and scientific studies drug on year after year, and it was not until 1743 that a result of their initial quest could be agreed upon and not until 1744 that two of the principal scientists (Charles-Marie de La Condamine and Pierre Bouguer) were able to leave Ecuador to return to France. They had measured more than 214 miles of meridian and proven beyond a doubt that the earth bulged at the equator. The ever-inquisitive La Condamine, chronicler of the expedition, used the occasion to map the Amazon River, while Louis Godin, the official leader of the expedition, was prevented by the authorities to leave Quito because of an unpaid debt and did not return to Paris until 1751. Three other members of the party had died in South America.
How does the mapmaker’s wife fit into all that? Louis Godin had a twenty-one-year-old cousin Jean Godin, who was "a born traveler" itching for an adventure. He was hired as an assistant, and was subsequently employed as a reconnaissance man and signal carrier, to call him a mapmaker seems somewhat of an exaggeration [Apparently King Louis XV thought otherwise because in 1773 he granted him the official title of "Geographer" with an annual pension of 700 francs]. By 1741 triangulation was essentially completed and Jean had time to pursue matters of the heart, so in December of that year he married in Quito a not yet fourteen-year-old old girl by the name of Isabel Gramesón.
Isabel Gramesón was the daughter of a distinguished colonial Spanish family. Her grandfather was French and Isabel was "exceedingly solicitous" to visit France; Jean seemed to provide an opportunity to get there. She was in for a thirty-two-year-long wait.
Jean struggled in various business ventures without much success and in 1749 decided to move his family to France. He left Quito in March of that year and made it down the Amazon and up the east coast of South America to French Guiana, flat broke and in need of a job. At home in Quito Isabel was waiting. As lonely year followed lonely year she longed to be with her husband, who tried but somehow never quite made it back the 3,000 miles across the Amazon basin to get her. After waiting twenty years Isabel grew desperate. In 1769 she took matters into her own hands and launched on an incredible ten months long journey, descending the east slope of the Andes, along the headwaters of the Amazon and down that then largely unexplored great river, enduring almost unbelievable hardship and barely escaping with her life, until she was reunited with Jean in French Guiana.
The story is well told and reading Robert Whitaker’s book pleased both, the surveyor and the romantic in me. Those of you who are only one or the other may want to skip a few chapters.
* Robert Whitaker: The Mapmaker’s Wife. Published by Bantam Dell, New York, NY. © 2004. Paperback, 354 p.p. $13.00