Einstein's Clocks and Poincare's Maps

by Peter Galison

  Cleveland Abbe, who had fought so hard with the American Metrological Society for unified time, doubted the naturalness of “neutral.” What if Russia were to reconquer the country on this side of the Bering Strait? What if America purchased half of Siberia? “That point [in the midst of the Bering Strait] is not cosmopolitan.” Only stars over the earth, something above human considerations, could possibly be deemed neutral.106

  Just so, interjected Sandford Fleming. Habituated to arguments in terms of the transport of goods and people, he viewed the French proposal for “a neutral meridian [as] excellent in theory, but I fear . . . entirely beyond the domain of practicability.” Then, shipping manifest in hand, Fleming recited numbers from a compilation of ships and transport tonnage that had been guided by the various prime meridians: Greenwich, 72 percent of tonnage; followed by Paris, 8 percent, with the rest of the world making up the remainder. Perhaps as a sop to his French colleagues, Fleming offered to set the prime meridian exactly 180 degrees from Greenwich, in the midst of the “uninhabited” part of the Pacific.107 Such a move would, he added, keep astronomical events practically unchanged on the Greenwich-based charts, inverting midnight and noon, 2:00 A.M. for 2:00 P.M., and so on. As for diplomacy, flipping the longitudinal line across the globe from London’s suburb fooled no one, least of all the French, who knew all about proxy prime meridians from their long use of Ferro. On a vote for a neutral meridian, the French plumped ‘for,’ joined only by Brazil and San Domingo. All twenty-one other nations voted against.

  Speaking for France, Lefaivre morosely assessed the debate as void of astronomy, geodesy, or navigation. Reminded of tonnages in the context of Anglo-American complacency, he allowed “the only merit of the Greenwich meridian . . . is that there are grouped around it, interests to be respected, I will acknowledge it willingly, by their magnitude, their energy, and their power of increasing, but entirely devoid of any claim on the impartial solicitude of science.” No reason, neutrality, or impartiality—only commerce pure and simple. Lefaivre conceded that the Empire had won by commercial prowess, but on no other grounds:

  Well, gentlemen, if we weigh these reasons—[the] only ones that at present militate for the Greenwich meridian—is it not evident that these are material superiorities, commercial preponderances that are going to influence your choice? Science appears here only as the humble vassal of the powers of the day to consecrate and crown their success. But, gentlemen, nothing is so transitory and fugitive as power and riches.

  All empires have fallen, and this one too shall pass. Do not enchain science and subordinate science. And will there be reward for the abandonment of our French meridian? Would America and Britain deign to take up the metric system? No. “We are simply invited to sacrifice traditions dear to our navy, to national science, by adding to that immolation pecuniary sacrifices.” Sir William Thomson, the senior scientist at the gathering, confirmed Janssen in all but his low opinion: this was a “business arrangement,” not a scientific question. The question was soon called for the adoption of “the meridian passing through the transit instrument at the Observatory of Greenwich as the initial meridian of longitude.” San Domingo voted against the sanctification of Greenwich; Brazil and France abstained. Twenty-one nations supported it.108

  Other issues racked the world longitude system, disputes that only made sense in a world wired for electrical time. Indeed, the whole conference could be seen as an extended conflict over the newly wired world of electrified time distribution. United States delegate W. F. Allen, fresh from his railroad time victory, offered the conference the logical asymptote of all these developments: “It would . . . be one of the possibilities of the powers of electricity that the pendulum of a single centrally located clock, beating seconds, could regulate the local time-reckoning of every city on the face of the earth.”109

  Against this ultimate time fantasy lay a universe of local customs; even the seemingly innocent question, When should the day begin? was vexed. Some favored commencing the day at the antimeridian of Rome to facilitate computation of ancient dates by the Gregorian calendar. Astronomers wanted the day’s start at noon to avoid splitting the night into two dates. Meanwhile, the Turkish delegate noted that the Ottoman Empire recognized midnight-to-midnight days (heure à la franque) but also reckoned from the bisection of the rising sun by the horizon (heure à la turque): “Reasons of a national and religious character prevent us . . . from abandoning this mode of counting our time.”110

  Important as these cross-cultural synchronizations were, no one at the conference doubted that the struggle was between Paris and Greenwich. Defeated in resolution after resolution, the French held one last hope: the decimalization of time. Their ambition for a rationale, scientific measure of time, analogous to the meter, had deep roots in Paris. In Year II of the French Revolution, the Convention struggled to institute a decimal system of time keeping with “decades” of ten days (rather than weeks), days partitioned into ten-hour units, and right angles split into 100, not 90 parts. A few revolutionary clocks still survive; one (figure 3.11) shows an equilateral tricolor triangle signifying that, under the new liberty, months would be divided in equal parts, with the vertices standing for days of rest. Among scientists, few took up the new system, but Laplace did in his epochal Celestial Mechanics, and sectors of the government even tried to impose the system. But faced with massive public resistance, Napoleon killed time decimalization in a deal cut with the Roman Catholic Church.111

  Janssen took the floor one last time to plead for the global instauration of this long-deferred decimal time and division of the circle. His hope—put as a resolution—was that the decimal system, now entering the mainstream of European trade and manufacturing, might finally be extended to time. Confronted with the same public opposition faced by his revolutionary forebears, Janssen reassured his colleagues: “It is feared that we want to destroy habits fixed for centuries, and upset established usages.” But no such fears were justified. “If we failed at the time of the Revolution, it is because we put forward a reform which was not limited to the domain of science, but which did violence to the habits of daily life.” This time it would not mandate a change for the people of the world, but only be imposed where it was of use.

  Figure 3.11 French Revolutionary Clock (circa 1793). The equilateral triangle signified that, under the new liberty, months would be divided into equal parts with the vertices standing for days of rest. SOURCE: ASSOCIATION FRANÇAISE DES AMATEURS D’HORLOGERIE ANCIENNE, REVUE DE L’ASSOCIATION FRANÇAISE, VOL. XX (1989), P. 211.

  At every stage of the story in France, from the meter to time and longitude, conventions of space and time were powerfully bound to the legacy of the Convention. But for all the delegates, and indeed for the larger metrological community behind them, settling on conventions of space and time was never just about precision maps or intersecting rails. To treat the Washington clashes as a step on an inevitable march toward standardized rationality is to miss the fluctuating, contingent, opalescent character of synchronization. It is to miss the constant crossing and recrossing of the pragmatic with the philosophical, the abstract with the concrete.

  After the French rout at the prime meridian, delegates looked for a way to accommodate the French on decimalized time without endorsing either its Enlightenment ambitions or any practical plan for its implementation. In the end, the conference merely expressed “the hope” that further technical studies on decimalizing time would be resumed.112 It was not much for the French delegates to carry home. To advance the cause beyond that minor, conciliatory vote, the French needed someone with stellar scientific credentials and engineering-administrative clout to champion this radical reformation of time conventions. For almost a decade the issue simmered uneasily in French technical circles. Enter Henri Poincaré.

  Chapter 4

  POINCARÉ’S MAPS

  Time, Reason, Nation

  AFTER THE 1884 World Time Conference set the prime meridian in Greenwich, resist
ance in France hardened. Janssen returned to Paris, still fuming from the rout. Appearing before the French Academy of Sciences on 9 March 1885, he recounted, blow by blow, the battles of the previous year, starting with the political: the Americans had loaded the meeting with small states that were allied to the U.S. Happily enough, there were some victories, he assured his colleagues, reprinting a long speech by the French delegation. One after the other, Janssen recalled, the Americans and British had taken the floor to fight the French, each Anglophone in his special domain of competence. “It is perhaps permitted to say, despite the authority, the talent, and the number of scientists who combated the principle of the neutrality of the meridian, that principle resisted these shocks without being disturbed and without any scientific breach. The meridian proposed by France remains still the impartial, scientific, and definitive solution to the question. We believe that there was honor to our country to have defended that cause.”1 On the Continent, Janssen was not alone in his discontent. The Abbe Tondine de Quarenghi campaigned in 1889–90 in the name of the Bologna Academy of Science for the prime meridian to be moved to Jerusalem, the Universal City “par excellence,” center of the three continents of the ancient world and the common sanctuary of three world religions.2

  Unlike France, Germany was not troubled by the Greenwich prime meridian. The Germans were preoccupied with their long A history of the quasi-autonomous states that had left the country struggling with a hodgepodge of mechanical and electrical time systems. It was this time disunity that brought the aging General Fieldmarshal Count Helmuth Carl Bernhard von Moltke to speak, on 16 March 1891, to the Imperial German Parliament. Railroads had been key to von Moltke’s celebrated triumph against France. For almost a half-century he had impressed upon his countrymen the vital role of trains in the rapid deployment of military assets. Already in 1843 he had insisted, “Every new development of railways is a military advantage; and for the national defence a few million on the completion of our railways is far more profitably employed than on our new fortresses.” Von Moltke drove these plans to completion, grounding his military strategy in the power of new railway lines. By the fall of 1867 he claimed that with the south German states he could have 360,000 men massed in three weeks and 430,000 in four.3

  Such planning paid. Not only the Germans but also their French adversaries recognized after the Franco-Prussian war of 1870–71 that von Moltke’s dextrous use of precision-synchronized trains had destroyed the Second Empire, fundamentally changing the balance of European power. For the twenty years following his triumph over France, von Moltke’s (and later Schlieffen’s) Great General Staff oversaw a massive expansion of the military as it grew into the force of a unified Reich. Patiently, obsessively, the generals ran an endless series of technical war games as they practiced the choreographed marshaling of 3 million soldiers using a hundred thousand train cars. In 1889 the military pleaded with the Reichstag to adopt standard time to simplify their train scheduling. The politicians refused.4

  Von Moltke of March 1891 was an unequaled hero in Prussia. When he entered a public place, men stood in silence until he took his seat. So when the general appeared before a plenary session of the Parliament on the subject of time and railroads, it was a major event.5 In his scratchy voice (he died just over a month later), von Moltke intoned:

  That unity of time (Einheitszeit) is indispensable for the satisfactory operating of railways is universally recognized, and is not disputed. But, meine Herren, we have in Germany five different units of time. In north Germany, including Saxony, we reckon by Berlin time; in Bavaria, by that of Munich; in Wurtemburg, by that of Stuttgart; in Baden, by that of Carlsruhe, and on the Rhine Palatinate by that of Ludwigshafen. We have thus in Germany five zones, with all the drawbacks and disadvantages which result. These we have in our own fatherland, besides those we dread to meet at the French and Russian boundaries. This is, I may say, a ruin which has remained standing out of the once splintered condition of Germany, but which, since we have become an empire, it is proper should be done away with.

  From the audience rang out: “sehr wahr” (very true). Von Moltke went on to say that while the current piecemeal ruin of time might only be an inconvenience for the traveler, it was an “actual difficulty of vital importance” for the railway business and, even worse, for the military. What, he asked, would happen in case of troop mobilization? There had to be a standard, one that would fall along the fifteenth meridian (about fifty miles east of the Brandenburg Gate), that would be the reference point; local times within Germany would differ but would require an offset by a mere half-hour or so on either extreme of the empire. “Meine Herren, unity of time merely for the railway does not set aside all the disadvantages which I have briefly mentioned; that will only be possible when we reach a unity of time reckoning for the whole of Germany, that is to say, when all local time is swept away.”6 Empire demanded it.

  Von Moltke conceded that the public might dissent. But after some “careful consideration,” scientific men of the observatories would set things right, and lend “their authority against this spirit of opposition.” “Meine Herren, science desires much more than we do. She is not content with a German unity of time, or with that of middle Europe, but she is desirous of obtaining a world time, based upon the meridian of Greenwich, and certainly with full right from her standpoint, and with the end she has in view.” Farms and factory workers could shift their clock starting times as they wished. If a manufacturer wanted his workers to start at the crack of dawn, then let him open the gates at 6:29 in March. Let the farmers follow the sun, let the schools and courts make do with their always loose schedules. Von Moltke wanted a nationally coordinated clock based on Greenwich. What mattered to the General Staff was that the railroads and armies should answer to a coordinated single time, one linked to the emerging electric worldmap. Much of Europe followed.7

  But not all Europeans. Perhaps the best known action against Greenwich is also one of the murkiest. On Thursday 15 February 1894, a young French anarchist, Martial Bourdin, bought a ticket from Westminster Bridge to Greenwich. According to one of two observatory assistants, when chatting in the lower computing room, the pair “were suddenly startled by a loud explosion, the detonation of which was sharp and clear. . . . I immediately remarked to Mr. Hollis, ‘That is dynamite! Spot the time’.” Trained to observe by the clock, they duly recorded the detonation at 4:51. When a policeman arrived at the detonation scene in the park below the observatory, he found Bourdin dying. The anarchist had lost his hand and received a massive blow of explosive and bomb fragments. For years, doubt lingered about Bourdin’s motives; anarchists suspected a police setup; others saw in it one more in the long series of French anarchist strikes, including one on the Chamber of Deputies in Paris (December 1893) and another in a Paris café just three days before Bourdin’s demise. Joseph Conrad’s version of the events in his 1907 work The Secret Agent remains the canvas on which these events have been seen: a dark sketch of dupes, manipulators, and careerists from which no one emerges unsullied. In Conrad’s world the conniving First Secretary of a Foreign Power insisted on an attack that would frighten the class enemies beyond murder: “The demonstration must be against learning—science. The attack must have all the shocking senselessness of gratuitous blasphemy.” It must strike at the mysterious scientific heart of material prosperity. “‘Yes,’ he continued with a contemptuous smile. ‘The blowing up of the first meridian is bound to raise a howl of execration.’”8

  Without a doubt the first meridian stood as a powerful if highly contested symbol. But even in France, where Janssen and others recoiled at Britain’s arrogation of world power, there were those who were entirely supportive of setting French time to the master clock of the great Christopher Wren observatory.

  Charles Lallemand, a member of the French Bureau of Longitude and an ally of Poincaré, made his support of Greenwich time crystal clear. Of course universal time (a single time for the whole world) would be an unmi
tigated disaster: the Japanese man in the street would surely refuse to live and work by the time it happened to be in Greenwich at that moment.9 Lallemand insisted that time reform would have remained mired in chaos if the North Americans, “with their admirable practical sense of Business’men, hadn’t imagined an ingenious compromise, uniting, or approximately so, all the advantages of the universal hour with that of local time”: time zones.10

  Writing in 1897, Lallemand insisted that it was an unparalleled victory in the domain of human reform that only ten years had sufficed for a simple, practical system of time zones to have conquered almost the totality of the civilized world. All of Europe now adhered to the system with the exception of France, Spain, and Portugal. What was needed for the French to join in this reform was so little: a delay of a mere 9 minutes and 21 seconds would set things right. Not only was the present system foolishly complicated, it meant, as Lallemand sadly noted, that on the other side of the earth, there was an equatorial zone spanning 250 miles between the antimeridian lines of Paris and Greenwich in which the very date was ambiguous. Standing (or floating) in that purgatorial time zone, you could class yourself as witnessing 31 December 1899 or 1 January 1900, depending on which set of maps lay before you.11

  For Lallemand, such ambiguity was intolerable. Objections flew fast and furious in this campaign of articles and broadsheets. Some claimed that the zones weren’t “neutral,” following the line taken at the contentious Washington meeting. False, Lallemand declared: Not only did the new zone system follow the standard, neutral twenty-four-hour clock, but the “vertiginous speed” of acceptance in both the new and old worlds had showed just how neutral it was. It is quite true, he conceded, that one meridial line ran through Greenwich. But that reference point was already familiar to nine-tenths of the world’s sailors. Can one really say that exchanging a longitude of zero for 9 minutes and 21 seconds would cause us to lose our French originality and scientific personality? Nonsense, he fulminated. Paris had long taken the position “20 degrees east,” using a first meridian on the island of Ferro. Even the much-vaunted neutrality of the revolutionary Convention that established the meter is not exact: what began in revolutionary France as a neutral measure (1 meter = 1/10,000,000 of a quarter of the circumference of the globe) rapidly deviated from that ideal as foreign nations copied a reference bar set in Paris. How, then, he demanded, could France possibly consider it a humiliation to modify its prime meridian? Some said it would render obsolete all French maps. No, Lallemand riposted, we could even overstrike the new longitude lines in a different color. He concluded that he and his countrymen would not be sacrificing their national meridian for the British. They would merely be offsetting their clocks by 9 minutes and 21 seconds for the benefit of telegraphy, navigation, and train travel. All “men of progress,” he concluded, should back the reformation of time.12