Mission to Quito
Poincaré’s—and the Bureau’s—engagement with telegraphic longitude work intensified between 1898 and 1900. Within a few months of the Bureau’s publication of their longitude fix of Dakar and Saint-Louis, the Bureau shifted into high gear to launch another major expedition, this time to Ecuador, with Poincaré as scientific secretary. Discussion of such an expedition had begun long before, certainly as far back as 1889 at the Exposition Universelle. In the midst of that techno-fair, the American delegate to the International Geodetic Association had asked for a determination of the length of a meridial arc (an arc along a line of longitude) as part of an effort to determine the shape of the earth. If the earth widened around the equator and flattened at the poles (as Newton had predicted two centuries earlier), then a longitudinal arc covering, say, 5 degrees of astronomical latitude near the equator should be shorter than a 5-degree arc nearer to one of the poles. That the earth was oblate was long known: the question now was to determine that shape with a precision fitting the age. The President of Ecuador approved, telling the French that they would have the full help of his government. As the proposal bounced between the Ministry of War, the Ministry of Foreign Affairs, and the Army’s Geographical Service, the cost began to rise, even as its importance remained clear.43 Nor did Ecuadorian politics hold still. With his ascension to Ecuador’s presidency on 5 June 1895, General Eloy Alfaro began the secular Liberal Revolution that aspired to reform every sector of national life. The bulging earth had to wait.
On 7 October 1898, the American delegate at that year’s International Geodetic Association meeting at Stuttgart again pleaded for a long-overdue remeasurement of the shape of the earth by way of an expedition to Quito, Ecuador. Bouquet de la Grye, the French delegate, reminded the assembled that, just four years previously, the Plenipotentiary Minister from Ecuador had proposed such an expedition but that the 1895 revolution had required an “adjournment” of the question. After the American delegate’s polite acknowledgment, the British representative spoke less diffidently: wishes were fine, but the geodesists needed to say precisely what could and should be done. London demanded France’s response to the need for meridial action. De la Grye was “persuaded that in France one would look with a favorable eye on the wish that we reopen negotiations on a new measurement of the arc of Peru.” Having watched American surveying forces nail locations up and down the Americas, and witnessing the British near-monopoly on undersea cables in pursuit of their own cartographic ambitions, the French understood full well that, if they hesitated, the American Coast Survey would grab the job. But if the Americans seized the map, as Poincaré put it, “the honor of our country would be ravished.”44 France mobilized.
From Paris the Minister of Public Instruction offered Fr. 20,000 for a reconnaissance mission to Quito using personnel assigned by the Minister of War. In this up-to-date foray, the Minister of Public Instruction would extend the much-heralded eighteenth-century measurement by 1 degree of latitude to the north and 2 degrees to the south, with the area around each base to be given topographical summaries and surveys of the horizon. Immediately, the French would send an avant-garde expedition that would move fast, traversing 3,500 kilometers of some of the highest mountains in the world in only four months. Departing from Bordeaux on 26 May 1899, the team worked at breakneck speed. While they were away, tensions with Britain mounted; there was the affair of the French cable lines that had “inexplicably” failed during the French-English race to stake colonial lands on the Nile, and then the outright British censorship of cables on 17 November 1899 during the Boer War. On 8 December 1899, the French Minister of Colonies announced a cable bill of unprecedented size. Just a week later, the Council of Ministers passed a plan for an imperial network budgeted at 100 million francs. Polemics over the cable project appeared in publications on both right and left.45 The Quito mapping team sailed back to France in the midst of this brouhaha, arriving in Paris on the last day of the nineteenth century.
At their meeting on Monday, 23 July 1900, it was up to the French Academy of Sciences to decide whether and how to undertake the full mission. Poincaré left little doubt as to the obligations he expected his country’s scientists to meet:
If our country owes itself its part in the conquests of modern science, then all the more reason we must not abandon a position on which our fathers hoisted, so to speak, the intellectual flag of France. Our rights have been publicly recognized. Should we respond to these courteous invitations by a declaration of impotence? France is as dynamic and richer than it was one hundred and fifty years ago. Why would she leave to younger nations the task of completing what the France of yesteryear had begun?46
The minister asked the Academy to control the operations; Poincaré urged the august body to go further. Shouldn’t they follow the legacy of their intrepid eighteenth-century forebears, Louis Godin, Pierre Bouguer, and Charles-Marie La Condamine, who had surveyed a degree of arc in Quito beginning in April of 1735? A century and a half later, however, academicians could well ask if it was necessary for scientists to accompany the expedition into the Andes. Such a voyage would demand more than calculational abilities, as the rather sedentary Poincaré conceded:
A high scientific competence, technical facility, and habits of scrupulous regularity would be indispensable, but would not suffice. One must be in a state that would support great exhaustion, in territory without resources and in every climate. One must know how to lead men, obtain obedience of one’s collaborators and impose that obedience on the half-civilized servants one is forced to employ. All these intellectual, physical, and moral qualities are found united in the officers of our geographical service.47
What the academy could do from the safety of Paris was to maintain scientific control by a commission charged with examining the observation notebooks.
Poincaré himself headed mission control. He made it clear in his report of 25 July 1900 that imposing the grid on this equatorial region would demand three bases. To ensure reliability, these should be located using the same instruments employed in determining meridian length in France. Quito itself would be manned by a most gifted (French) astronomer, François Gonnessiat of the Lyon Observatory, with the whole operation generously funded by an anonymous donor later revealed to be Prince Roland Bonaparte. With French officers operating the extreme stations, Gonnessiat would make simultaneous observations at Quito, ensuring accurate longitude fixes. As always, the telegraph was key in the establishment of distant simultaneity: one wire would run from Quito to Gayaquil, boosting its signal with a relay; another would tie Quito to the distant north station. If the relays introduced unacceptable error into the simultaneity determination, as they often did, Poincaré was prepared to slice them from the system by boosting the battery power of the initial station. At present, the team was already working to string the telegraph network all the way to the southern station. So the extreme ends of this far-flung mountain network would be tied back to Quito, with Quito’s time bound to Gayaquil’s. Gayaquil, in turn, would coordinate its clocks through undersea cables tied to the general world network via North America.48
Figure 4.3 Quito Meridian. Poincaré reported regularly on the Quito expedition. In this picture, the multiple triangulations are shown; these were used to measure the length of a longitudinal arc in order to give greater precision to the shape of the earth. This network of latitude and longitude measurements was then linked by cable to the world telegraph net—and would be calibrated to the French prime meridian. SOURCE: POINCARÉ, OEUVRES COMPLÈTES, VOL. 5, P. 575.
The academy approved Poincaré’s report as did the International Geodetic Association in October 1900, with the American delegate congratulating the French and reminding them that the United States would like to be asked first if any additional help were needed. Not likely. On 9 December 1900, Captains Maurain (of the engineers) and Lallemand (of the artillery) left for Ecuador as the avant-garde of what they expected would be a four-year mission
to Quito.49
On Monday, 28 April 1902, Poincaré reported to the Academicians in Paris: Members of the advanced team had spent months buying pack animals and setting up their convoys. By the time they started up into the mountains, the French expeditionary force had 120 mules and were accompanied by forty Indian porters and six Ecuadorian officers. The vital measuring stick, consisting of two different metals with different responses to heat, had to be carried on a man’s back. At night the humidity so distorted the micrometer threads that they used for sighting that observations became almost impossible between six and nine in the morning. Then, at 11:00 A.M., howling winds blasted dust through every crevice in the campsite, wrecking instruments and torturing the explorers. Wild temperature changes plunged through the camp so quickly that the team wondered if their measuring devices would ever settle into a reliable state of equilibrium. Amidst all this, the French decided they would prefer to use their personal equations rather than switch positions of the observers, which would have left Indians, alone, in charge of the base camp. Lallemand took two men on a side mission to the far north in the hopes of extending the network into Colombia, but they were promptly stymied by political turbulence. In a somewhat optimistic aside, Poincaré conveyed the expedition leaders’ hope that, before 1904, they would have established telegraphic simultaneity to all the far north stations short of Colombia.50
A year later, Poincaré was back before the Academy, once again having drafted a report on the hard-driving expedition. It was Monday, 6 April 1903, and the commissioners noted with regret that the previous year’s progress had been held up on almost every front. First the summits were almost constantly lost in fog, making sightings impossible. Lieutenant Perrier had spent three months at his assigned post in Mirador, 12,000 feet above sea level, almost constantly blanketed in clouds. Incessant rain pounded on his site, the visible horizon limited to the camp itself. Furious winds shook everything in the barracks. In one period of fifteen days, he was able to make but one of his twenty-one measurements and caught not a single glimpse of the signal he awaited from Yura Cruz. The valleys separating them flowed with a rushing river of clouds from the East. After months of isolation, Perrier’s perseverance was rewarded with calmer, clearer weather. In an intense burst of activity, the lieutenant completed his mission.51
Other brigades faced similar problems and, by Poincaré’s reckoning, gave the same proof of their quality. At Tacunga, Captain Maurain could only observe intermittently, seizing upon occasional clearing. A violent east wind accompanied by snow squalls made his work exceedingly painful. Gusts tore roof braces from the observation station, ripping up tents right and left. At Cahuito station Lacombe found himself stranded for days in the fog and snow, unable to execute a single observation. And Lallemand, who directed the reconnaissance brigade and signal construction across exceedingly tough terrain, fell into a crevasse in Cotopaxi. Other soldiers recovered him, but for three weeks he was laid low. Amidst these battles with the elements, the team speculated that the ferocious weather might be linked to the volcanic activity following a catastrophic eruption on Martinique.52
But not all the misfortunes of the longitude men could be laid at the feet of nature. Both indigenous whites and Indians tore into the geodesists’ painfully established reference points. Apparently surveying rods signaled more than lat-long positions. For locals, these markers promised buried wealth. In their search for gold, not only did the treasure hunters remove rods, they dug up everything remotely near them. So the French—after their months in the oxygen-deprived, snow-driven peaks—had to resignal, remeasure, and re-mark the sites, sometimes two or even three times. Enlisting the Church, the French enjoined local bishops and cures to stave off the inhabitants, but neither science nor God deterred the diggers. Over the course of 1904, the French found their stations destroyed some eighteen times, forcing the remeasurement of 360 pairs of points in horrendous high-mountain conditions. The following year, to their dismay, the simultaneity team realized, while freezing in the craggy heights, that their native informants’ reports on visibility had been, as they put it, “not exact.” The geographers finally understood that their informants had never voluntarily gone anywhere near such heights. On those few occasions that the locals had actually ventured to high altitudes, “visibility” meant being able to see enough to climb and descend. Unlike the forces of simultaneity, the native people had neither a need nor a desire to see far enough to flash latitude and longitude. Meanwhile Lallemand contracted yellow fever; his colleagues sent him back to France.
Poincaré delivered this encomium for the mission: “The long days of waiting in snow and fog did not lead to an instant of discouragement and the zeal, the constancy, and the devotion of these officers and of all the personnel ought never be denied. There are grounds for congratulating these valiant pioneers of Science for their courage and the results they obtained.”53 Map coordinates in hand, after eight years of effort to fix time and space, Poincaré reported in 1907 that the expedition had returned to France.
Etherial Time
In following the Quito expedition all the way back to Paris, we have gotten ahead of ourselves. For during the entire span of the longitude expedition—from planning in 1899 to its conclusion in 1907—Poincaré pressed the technology of simultaneity in two other, very different domains: philosophy and physics. This was no accident. From the time he completed his report on the Quito mission’s objectives (25 July 1900), Poincaré was fully immersed in the details of telegraphic simultaneity, down to the battery power of the telegraph lines. He had made the case to his colleagues that mapping Quito was of double importance—as a defense of French honor (“hoisting the intellectual flag of France”) and as a technical-scientific problem (determining the shape of the earth, mapping the world). But that was not all.
No longer thinking purely mathematically, Poincaré now reflected on the philosophical, conventional basis of physics more generally. Just a few days after urging the Quito project on his fellow Academicians, he delivered a paper at a major philosophy conference (2 August 1900),54 where he asked a fundamental question about what he considered the most central science: could the basic ideas of mechanics itself be altered? Among his French compatriots, Poincaré argued, mechanics had long been treated as beyond the reach of experience, as a deductive science that would inevitably lead to conclusions from assumed first principles. By contrast, British mechanics was at root not a theoretical but an experimental science. If there was going to be any real progress in mechanics, this cross-channel clash would have to be sorted out analytically. What part of this most exalted science was experimental? What part mathematical? And—as he put it—what part conventional?
In response, Poincaré laid out for the philosophers his judgment of what we knew about the starting points of this most fundamental of sciences, drawing from the full range of his work on the foundations of geometry, geodesy, physics, and philosophy. In his words:
1. There is no absolute space, and we only conceive of relative motion; and yet in most cases mechanical facts are enunciated as if there is an absolute space to which they can be referred.
2. There is no absolute time. When we say that two periods are equal, the statement has no meaning, and can only acquire a meaning by a convention.
3. Not only have we no direct intuition of the equality of two periods, but we have not even direct intuition of the simultaneity of two events occurring in two different places. I have explained this in an article entitled “Mesure du Temps.”
4. Finally, is not Euclidean geometry in itself only a kind of convention of language?
For Poincaré, mechanics could be alternately enunciated using a non-Euclidean geometry. It might be less convenient than mechanics articulated using ordinary Euclidean geometry, but it would be altogether as legitimate. Absolute time, absolute space, absolute simultaneity, and even absolute (Euclidean) geometry were not imposed on mechanics. Such absolutes “no more existed before mechanics than the Frenc
h language can be logically said to have existed before the truths which are expressed in French.”55
These four summary statements captured a great deal of Poincaré’s approach. The first reemphasized his philosophical-physical objection to absolute space. The second and third recapped his 1898 “Measure of Time,” and the fourth linked the discussion to his older work on the conventionality of geometry. “Are the laws of acceleration and of the composition of forces only arbitrary conventions? Conventions, yes; arbitrary, no—they would be so if we lost sight of the experiments which led the founders of the science to adopt them, and which, imperfect as they were, were sufficient to justify their adoption. It is well from time to time to let our attention dwell on the experimental origin of these conventions.” Experiments, for Poincaré, were the raw materials of physics out of which theory aimed to produce the greatest number of predictions with the highest probability. That is, experiments could serve as the “basis” for mechanics by suggesting, as it were, the principles and rough behavior of the world that we want embodied in the conventions (definitions) of concepts such as force, mass, and acceleration. But that is not to say that experiments can simply invalidate starting principles; at worst, in his view, experiments would reveal that a fundamental law was only approximately true, “and we know that already.”56 Poincaré summarized his reflections on the role of theory when he spoke to the physicists (also in 1900). As so often, he invoked the machine-based factory, framing experiments as the “raw materials” and theory as the organizing guide: “The problem is, so to speak, to increase the output of the scientific machine.”57
Einstein's Clocks and Poincare's Maps Page 19