Monday, 14 October 2019

French scientists at the Equator, 1735

Voyages of Discovery:  the Figure of the Earth (BBC,2006)

Last week BBC4 repeated a documentary on the French geodesic mission of 1735, one of the Voyages of Discovery series introduced by explorer and broadcaster Paul Rose.  It was originally broadcast in 2006.   Having missed it the first time round, I was pleased to catch the repeat.  The production was  marred by some truly dreadful dramatic reconstructions which made La Condamine and his colleagues look like caricatures out of Horrible Histories.  However, the filming on location in Peru was stunning. The historical consultant for the programme was the American naval historian Larrie Ferreiro, who has since written a well-regarded full-scale study of the expedition.(Measure of the Earth, published 2011)

I found it difficult in places to piece together events from the information given, so here is a summary of the main points of the narrative, plus a few supplementary "viewing notes".

The mission

In 1735 the Academy of Sciences, with the support of Maurepas, sent out an expedition to Ecuador (then the province of Quito in the Spanish Viceroyalty of Peru).  Its purpose was to resolve current controversy over the shape of the earth by establishing an exact  measurement for the curvature of the earth at the Equator.  In 1737 Maupertius led a similar, rival mission to Lapland to obtain a comparative reading close to the Pole.

The voyage out

[3:25] La Rochelle, 11th May 1735,

The members of the expedition  took passage for the first leg of their journey on board a naval frigate, the Portefaix. The ship is seen setting sail for Martinique and Saint-Domingue, with the scientists, their luggage and their state-of-the-art surveying  instruments on board.  The three principal participants are introduced: Pierre Bouguer, aged 37, mathematician and former child prodigy, La Condamine, aged 34, with four years experience in the military, Louis Godin, ambitious mathematician and astronomer, aged 31, the leader of the mission.

Perhaps rather too much is made of the trio as "bookish academics"[0:30] and the "very antithesis of rugged explorers" [5:15].  La Condamine was a restless adventurer after Paul Rose's own heart.  He had started out as an army officer and and seen action at the seige of  Rosas in 1719 where  he had shown "the combination of curiosity, bravery, and sheer idiocy that would mark his entire career"(Ferreiro, p.23) In 1731-32 he had sailed with the famous corsair René Duguay-Trouin to North Africa, Greece and Turkey.

In the West Indies

[8: 45] Paul Rose explains that the expedition now "make their first big mistake".  Stopping off at Saint-Domingue, the imperious and irresponsible Godin dismayed his colleagues by squandering 1,000 ecus of the expedition's fund on a diamond for a local prostitute.  A letter home from the ship's surgeon Seniergues describes the scientists as "fighting like cats and dogs". Paul notes sagely that a close-knit team is an essential to the success of an exploratory mission.

In Peru/Ecuador

[13:15]:  On March 10th 1735, the scientists reached Peru and headed  inland to the capital Quito in search of funds. They were now in largely uncharted territory.  Paul has a giddy ride on a cable car across a precipitous gorge and introduces the dangers of Amazon bears, snakes and mosquitos.  Against the golden rules of exploration, the scientists elected to travel separately, "a crazy thing to do". The main party, with the equipment and guides, set off for Quito, leaving La Condamine to proceed overland entirely alone.

The Province of Quito in the 1730s. []

The party had remained in Saint- Domingue for over three months (July-October) while they negotiated with the Spanish authorities and waited for a ship to be readied for the onward journey.  In Cartagena they were joined by two young Spanish naval officers,Antonio de Ulloa and Jorge Juan y Santacilia. They then sailed to Portobelo on the northern coast of Panama in order to cross the isthmus, and travel south to Ecuador.  In Portobelo they again faced delay whilst boats  for the journey inland were found and loaded; conditions in the port were notoriously miserable; heat, heavy rains and fever that meant that the Spanish fleet regularly lost a third or a half of its crew.  They  paddled and poled their way in dugouts up the alligator-infested Chagres river, then trekked on mules to Panama on the Pacific coast.  A further 800-miles by sea brought them finally to the coast of Quito, where they anchored in Manta on 10th March 1736. Almost a year had passed since the expedition  left Paris.  As Larrie Ferreiro also emphasises in his book, the party was racked with dissent.

On the Chagres river; illustration from the Relacion of Ulloa and Juan

On 13 March 1736  the main company, Godin, with Spanish officers set sail, as had been originally planned, for Guayaquil at the mouth of the Guayas river, which was the established route to Quita.  Bouguer and La Condamine elected to remain in order to carry out  astronomical observations and determine whether the coastal region was suitable for the geodesic survey. (It wasn't). On 23rd April, when Bouguer's health began to fail, the two men in turn parted company and La Condamine set out recklessly alone.  He arrived in Quito on 4th June.

On the Palmar promontory, La Condamine patriotically marked the point at which the equator crosses the coastline of Peru,  - as determined "by the astronomical observations of the Royal Academy of Sciences Paris" [Illustration for the Preface to La Condamine's Journal historique]     

To Quito in the footsteps of La Condamine

In this part of the documentary, Paul Rose retraces La Condamine's route.
[16:30]: Esmeraldas, 11 months after departure
La Condamine faced "one of the world's most hostile environments". He canoed 150 miles up the coast with only his servant and a slave,  then made his way inland up the  Esmeraldas river through dense rainforest. (Rose freely admits he  doesn't like jungles!)

[17:25]-[21:30]:  La Condamine's discovery of rubber:  Rose watches a rubber tree being tapped by a native of the region. La Condamine collected seed samples and wrote a meticulous paper, hereby  "kick-starting the rubber industry". This was one of the several significant chance discoveries made in the course of the mission.

[21:50] At one point La Condamine narrowly escaped death when he became lost for eight days  and developed a fever: 

You can read La Condamine's own account in his Journal historique:
May 1736:  This whole terrain was covered with dense jungle that had to be cut through with an axe; I travelled with my compass and thermometer in my hands, more often on foot than on horseback.  It rained regularly every afternoon.  I brought  with me various instruments and a huge quadrant, that two Indians could scarcely carry.  I collected and drew numerous plants and seeds in the jungle which I left with M. de Jussieu [ the expedition's botanist Joseph de Jussieu] in Quito.  I remained for eight days in this wilderness abandoned by my guides, lacking both powder and provisions; bananas and wild fruits were my only sustenance.  I took a fever;  I cured myself through fasting, which was decreed both by reason and necessity.

[25:05] Finally he emerged from the jungle.  Scaling the volcano Rucu Richincha, he saw the city of Quito spectacularly spread before him on its eastern slopes:

..I was seized by a sense of wonder mixed with admiration, at the appearance of a large valley five to six leagues wide, interspersed with streams which joined together: I saw, as far as my eye could see, cultivated lands, divided between plains 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 beautiful days in May. Each instant I added to my surprise; I saw, for the first time, flowers, buds and fruit in the middle of the countryside on all of the trees. I saw people planting, labouring and harvesting all on the same day and in the same place. I have let myself become carried away by the memory of the first impression I had then, quite forgetting that this [journal] is only a place for recounting our academic work.
(Journal, p.13-14)

The tribulations of the main party are recounted in the Relacion of Ulloa and Juan. In Guayaquil they were delayed by the swollen waters. On the river, the mosquitos were "beyond imagination":  swarms of insects would extinguish their candles and, despite clothes and netting, their faces were swollen with enormous bites. They struggled into thick jungle, through a watery morass that went up to their horses' knees, across bridges high above  precipitous river gorges.  In the Chimborazo desert they experienced wind and freezing temperatures.  By the time they reached the lower slopes of the 20,600-foot Chimborazo volcano, they were reduced to a few miles a day, as their mules struggled for  a footing and had to rest after a few steps (Voyage, p.195ff.)

In Quito

[24:00] Quito. 1 Year, 16 Days after departure 

In Quito the expedition ran foul of  the Spanish governor Alsado [Dionisio de Alsedo y Herrera, president of the audiencia of Quito] who refused them further assistance.

[25:25] All hopes of saving the mission now rested on the superior social standing of La Condamine.  Perversely he at first refused to meet Alsedo, since "he did not even have decent clothes ", though after a week he was presented and saved relations.  Paul Rose visits (briefly) the Jesuit college where La Condamine stayed and the "Yellow Hall" of the Presidential Palace in Quito.

29:25: Cayambe, 1 year, 4 months after departure

The expedition finally set out out into wilderness towards the Equator to begin its work.  Within days Jacques Couplet, the youngest member of the team, tragically died of malaria. 

[31:50] In January 1737 La Condamine was obliged to set out on a 1,500 mile trek to Lima to secure funds.  He successfully secured a loan of 12,000 pesos to enable them to begin survey work.  (He had previously had the forethought to secure personal letters of credit worth 20,000 pesos which he proposed to go to Lima to exchange)

[32:50]-[35:30] La Condamine  discovers  red quinine.  After La Condamine's preliminary report, Jussieu made further investigations and extended his findings.

The Survey 

[36:50]: Paul visits the Ciudad Mitad del Mundo outside Quito, a monument built on the line of the Equator in 1935 to commemorate the expedition.  The statue  to the right of the screen is La Condamine.

Paul now explains how the survey was to be carried out. The aim was to obtain the exact measurement of a degree of latitude at the Equator. The first stage required the establishment of  a long line across the Equator of known length. This was to be calculated by triangulation using the heights of the Andes for sightings [39:04].

Illustration from:  Fernie,“Marginalia: The Shape of the Earth.” American Scientist, vol.79 (2) 1991, pp.108–110. 

A baseline was first painstakingly established.  The Yaruqui plateau to the north of Quito, was eventually chosen as a site, with timber and thatch stations marking each end.  The seven-mile line was measured forward and backward with twenty-foot poles agreement to within three inches. The surveyors then triangulated southwards for over 200 miles (almost three degrees of latitude), an exercise which required nearly 70 survey stations. 

Here is the line of triangulation as shown in the documentary.  [Compare Bouguer's map:]

[38:05] The Andes, 1 year, 5 months after departure

To establish their triangulation points the survey team was obliged to negotiate some of the world's most inhospitable terrain.

[40:35]: The expedition split into two teams, and set about climbing the Andes mountain by mountain. (The reconstructions at this point are truly excruciating.)

[41:05] We follow Paul Rose on the Pic de Pitchincha. At over 14,000 feet, this was the first, and one of the most challenging triangulation stations, "a really tough opener". The peak was swept by icy winds, the sight lines commonly obliterated  by freezing fog, hail and snow.  The men suffered from  altitude sickness,"the rarefactions of the air", which they did not fully understand and took no precautions against.   At the peak they were blighted by extreme cold:  their faces, hands and feet became swollen with chilblains;.with clothes, eyelashes and eyebrows covered in icicles, they "provided each other with a singular spectacle".  They huddled in a tiny hut they had hauled piece by piece up the mountain, sustained only by rations of boiled rice, fowl and melted snow. Finally, after 23 days, they gave up and planted their marker halfway down. They had taken four months to get just one measurement; and they had twenty-five mountains left to negotiate!

[44:10]: Paul climbs Cotapaxi, the world's highest active volcano.  Our intrepid explorer is finally in his element - he has led expeditions to Cotapaxi six times!

It soon became clear that the mission would take much longer than had been anticipated.

[45:55]-[48:05]:  La Condamine's contribution to the development of the metric system.  In the marketplace we meet Larrie Ferreiro himself, who considers La Condamine's theories on the metric system to be one of his most important achievements.  The French Revolution defined the universal metre as one ten millionth of distance from north pole to equator.

After two years in the mountains, the expedition finally completed the triangulation.

The survey at work - chapter heading from La Condamine's 1751 report to the Academy of Science

In Cuenca

[48:55]-[52:25]: Cuenca, 4 years 2 months after departure

The final phase of the survey was to carry out observations at either end of the triangulated line in order to determine the exact measurement of a single degree of latitude. 

Engraving by Tardieu of the bullfight in Cuenca

In Cuenca, at the southern extremity,  the Frenchmen experienced an unexpected tragedy when their party was attacked at a bullfight. The ship's surgon Senièrgues. who had antagonised local feeling, was fatally wounded and Bouguer was stabbed (though he subsequently recovered).

[53:15]:  Paul and Larrie Ferreiro visit the church in Cuenco 
where the the observations were carried out.  Ferreiro provides a demonstration, with a plastic drainpipe, of the use of a zenith sector to determine latitude.  The observations had to be performed simultaneously at both ends of the baseline. 

Illustration from La Condamine's report, Mesure des trois premiers degres du meridien
Rather than measure a star's altitude above the horizon, the zenith sector measures the difference between the star's position and a point directly overhead.  The long stationery arm of the sector would be aligned along a vertical axis, and the telescope would be pointed at the star as it crossed the local meridian.  The angle between the two could then be measured;  by taking readings at different points on the north-south line the difference in latitude between them was determined.  La Condamine and Bouguer took the twelve-foot sector that they had brought from France to the plains of Yarqui where they built an observatory.  Godin  had a second sector constructed and used the belltower of the church in Cuena as his  makeshift laboratory.

These observations took three years to complete.  Their final calculation (110.61 kilometres  for one degree of latitude) confirmed definitively that the Earth was oblate as Newton had hypothesised.

Following the completion of the mission, the group split up.  Louis Godin took up a post as an astronomer in the University in Lima;  Bouguer and La Condamine departed on separate routes early in 1743;  in a  further remarkable feat of exploration, La Condamine was to descend the eastern slopes of the Andes and travel the length of the Amazon to the Atlantic.

The expedition, originally planned for three years, had finally taken almost nine.


Contemporary accounts:

Most of the beautiful books produced by the expedition members can be viewed conveniently in the Biodiversity Heritage Library e-book collection:

 Charles-Marie de La Condamine,  Mesure des trois premiers degrés du méridien dans l'hémisphere austral (Imprimerie royale, 1751)
______, Journal du Voyage fait par ordre du Roi, a l'Equateur, (Imprimerie royale, 1751)

Pierre Bouguer, La Figure de la terre (1749)

Antonio de Ulloa and Jorge Juan, Relacion Historica del Viage a la America Meridional vol. 1 (1772)
In Spanish:
English translation:

Modern studies:

Larrie Ferreiro, Measure of the Earth: The Enlightenment Expedition That Reshaped Our World ,New York : Basic Books, 2011.
There is an interview with Larrie Ferreiro in Popular Mechanics

Fernie, J. Donald. “Marginalia: The Shape of the Earth.” American Scientist, vol.79 (2) 1991, pp.108–110. JSTOR,

"Expedition of Maupertius to Lapland to determine the shape of the Earth", Pello-Lapland; [Pello Travel website]

I also very much enjoyed reading Robert Whitaker's The Mapmaker's wife (Bantam Books, 2004).  This  book tells the story of a junior member of the survey team, Jean Godin, and his Peruvian wife Isabel Grameson, who made an epic trek across the South American continent to rejoin him when he became stranded after the expedition.

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