;)
n June 1792 -- in the dying days of the
French monarchy, as the world began to revolve around a new
promise of revolutionary equality -- two astronomers set out
in opposite directions on an extraordinary quest,'' Ken Alder
writes in the opening sentence of his highly original new
book. ''Their hope was that all the world's peoples would
henceforth use the globe as their common standard of
measure.'' The new unit of measurement, to be called the
meter, was to equal exactly one ten-millionth of the distance
from the North Pole to the Equator. That ''exactly'' was to be
the two astronomers' goal, their glory and their curse.
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In theory, theirs was a straightforward task. Each
astronomer would map a chain of triangles straddling a line of
longitude extending from Dunkirk south to Barcelona. This
involved sighting among remote mountaintops, church steeples
and fortress ramparts, using whatever combinations of signal
flags, reflectors, torches and the like could be made visible
across long distances, to measure the angles between these
points; and then measuring the angles between these points to
draw huge, imaginary triangles across the countryside. The
measurements were made with ''repeating circles,'' brass
masterpieces of 18th-century technology. Once the triangles
were mapped, all that remained was to chart a pair of
baselines, one in the north and the other in the south. The
sizes of all the triangles would then be known, the value of
this particular slice of the earth's circumference would be
established, and the true length of the meter could be
announced to a more or less waiting world. Based on the globe
itself rather than any one nation, the new metric system
''would belong equally to all the people of the world, just as
the earth belonged equally to them all,'' Alder writes.
It should have been the work of months. But owing mainly to
the revolutionary zeal that inspired the project in the first
place, the two savants, tossed like wood chips down the white
waters of a world at war, wound up spending fully seven years
in the field. Negotiating rutted back roads in their twin
customized carriages and deploying their gleaming surveying
instruments over lands embroiled in chaos, they were detained,
arrested, and otherwise harassed in ways sufficiently
confounding as to seem less at home in a work of popular
science than a novel by Cervantes or Rabelais.
The dramatic possibilities of their troubled odysseys,
which declined from comedy to tragedy and finally farce, are
not lost on Alder, a Northwestern University historian whose
deft writing style gleams like spar varnish atop a stout deck
of extensive research. Along with consulting the heaps of
books that such projects normally require, Alder evidently
read all the relevant surviving books, logs and letters, some
of them examined by no prior scholar.
He also retraced the astronomers' routes, by bicycle: ''I
climbed the cathedral towers and mountain peaks from which
they conducted their survey, and combed the provincial
archives for traces of their passage. It was my own Tour de
France.'' Thanks to this admirably direct approach, ''The
Measure of All Things'' is graced by a vividly descriptive
sense of place. The Corbieres mountain range, Alder tells us,
is ''a landscape of stony valleys dominated by ruined
castles.'' The Puy de Dome and its neighboring peaks are ''a
row of brooding beehive volcanoes, their black humps flecked
with snow.'' The town of Salers is ''an onyx outpost of
judicial palaces, slate-roofed inns, and black-stone
battlements.'' There is no smell of the lamp to this book, and
although it occasionally succumbs to the fatigue of the
long-distance researcher/bicycler, all in all it's a journey
worth taking.
From the start, the mission to measure the meter had its
critics, some of whom saw it as a superfluous attempt to gin
up global authority for what was, after all, just a new kind
of measuring stick. ''Was it really necessary,'' one asked,
''to go so far to find what lay so near?'' Lines of longitude
had already been measured by competent French geographers,
albeit with less than the wished-for exactitude; why not just
agree on a reasonably accurate standard for the meter and let
it go at that? The ranks of prestigious metric skeptics
included the revolutionary journalist Jean-Paul Marat, who,
Alder notes, coined the word scientifiques (scientists), in
1792 ''when he referred sneeringly to the academicians'
self-serving project to measure the earth in order to create
uniform weights and measures.'' But the National Assembly,
bent on establishing a measurement system that would
''encompass nothing that was arbitrary, nor to the particular
advantage of any people on the planet,'' came through with the
requisite funding. And so the astronomers set forth.
The northbound of the two, the ''erudite and cosmopolitan''
Jean-Baptiste-Joseph Delambre, ran into trouble almost from
the start when, near the valley of Brie, he and his assistants
were detained overnight by militiamen. (Their papers, signed
by King Louis XVI four months earlier, had become invalid when
Louis was deposed.) They managed to gain their release and
journey on to Saint-Denis. There, a hostile mob, eager to
execute Delambre as a noisome aristocrat, was assuaged only
after he gave a popular-science lecture in the town square,
explaining the revolutionary validity and apolitical nature of
the mapping campaign. But when he later draped a clock tower
in Herment to make it more readily visible through a distant
telescope, ''the locals balked,'' Alder writes. ''White was
the color of the royalist flag -- and the region's
administrators were battling a reactionary resurgence. . . .
To appease the patriots, Delambre sewed a red strip of cloth
to one edge of the white sheet and a blue strip to the other,
transforming his signal into a makeshift Revolutionary
tricolor flag.''
In the Orleans forest near the Loire River, 600 soldiers
were summoned by local citizens to attack another of
Delambre's marking towers, which they imagined was being built
''in preparation for a counterrevolutionary uprising.''
Fortunately for the astronomer, they changed their minds at
the last moment and instead destroyed a stone obelisk erected
in honor of an earlier survey, which they regarded as an
''odious sign of extinct despotism . . . built by the one-time
lords as a sign of their greatness.'' Constantly hobbled by
such efforts, Delambre made, in Alder's words, ''progress
worthy of Don Quixote.''
All of which was a ramble in the park compared to the
fortunes of the southward-venturing astronomer,
Pierre-Francois-Andre Mechain. He had triangulated his way
into Spain when the French, feeling refreshed after
decapitating Louis XVI, declared war on Spain. Stranded in the
south, Mechain made astronomical measurements of Barcelona's
latitude before being badly injured in a near-fatal accident
when a physician friend, Francesc Salva i Campillo, insisted
on demonstrating the mechanical wonders of a local pumping
station. The pump handle rebounded, all but crushing Mechain.
Never quite the same thereafter, Mechain retreated to Italy
and eventually made his way back to France, where he wandered
for another three years, occasionally managing to complete a
few triangles but mostly bemoaning his fate. ''The ambition to
be useful and win a little glory, which once animated me,
turns out to have been a vain fantasy,'' he wrote. ''I am now
trying to contain and calm the deadly disgust which is killing
me.'' In the end it took the intervention of Delambre himself
to bring Mechain down from the mountains and back to Paris,
where after years of self-imposed exile he was reunited with
his wife and children, ''who,'' Alder notes, ''hardly knew
him.''
To some extent Mechain's reluctance to return home was
justified by the terrifying news coming from Paris, where
scientists were routinely being persecuted in the name of
reason. The eminent mathematician the Marquis de Condorcet --
a revolutionary firebrand who had enthusiastically supported
the expedition, heralding the metric system as a legacy ''for
all people, for all time'' -- was condemned by the Committee
of Public Safety, and committed suicide rather than face
capture. Another of the expedition's enthusiasts, the chemist
Antoine-Laurent Lavoisier, was guillotined, on May 8, 1794. A
third, the astronomer Jean-Dominique de Cassini, was
imprisoned on the testimony of one of his students -- who soon
joined him, charged with the offense of having made an
erroneous measurement of the sun.
But the main problem was that Mechain had pretty much gone
mad. Alder allows that ''Mechain was depressive, we would say;
he was paranoid, obsessive, passive-aggressive,'' but he puts
most of the blame on Mechain's anguish over certain
discrepancies in his data.
These discrepancies -- which certainly were the focus, if
not entirely the cause, of Mechain's dementia -- were of two
sorts. One had to do with his measurements of the latitude of
Barcelona. They were incorrect, owing to mistakes in the
tables commonly used by astronomers of the day to compensate
for refraction -- the change in the apparent position of stars
near the horizon caused by the distorting effects of the
earth's atmosphere. The other, which would not come fully to
light until years later, when Delambre reduced the data in the
course of producing his magnum opus, ''The Foundation of the
Metric System,'' was that variations in the shape of the earth
from that of a perfect sphere exposed a fundamental flaw in
the project. This is the ''hidden error'' in the subtitle of
Alder's book. The critics had been right all along: measuring
such a north-south longitude line couldn't really produce a
precise value for the meter. The earth itself was guilty of
inexactitude.
Following Mechain's long wanderings through his intensely
neurotic, half-batty letters, some readers may soon grow
accountably tired and sick of this particular learned
astronomer, and Alder might have done well to skip a triangle
or two and cut to the chase. But those who persist will be
rewarded with the full sweep of an unusually capable and
well-written book that adeptly sets its yarn of exploration
amid the wider context of a world awakening to the pleasures
and perils of scientific exactitude.
Alder astutely details the advantages of the metric scheme.
Admirably clear and consistent, it established one measurement
standard where previously there had been many. France alone
had dozens of such systems, as did most other nations. ''When
a volunteer from Saint-Denis visited Paris to hoist a pinte of
beer to salute his Parisian comrades, he discovered that the
pinte of Paris held two-thirds the beer of his hometown
pinte,'' Alder writes. ''The bakers in the crowd used a livre
(pound) that was lighter than the livre of the ironmongers.
In many parts of France, a pound of bread really did weigh
less than a pound of lead.'' The French Academy of Sciences
itself became a victim of such variations: once an official
length of the meter had finally been established, following
the verdict of what Alder describes as ''the world's first
international scientific conference,'' in Paris in 1799, the
commissioners charged with forging the International Meter Bar
had to scramble to find enough platinum to do the job, because
''the final shipment from Spain had been short-weighted by 15
percent.'' The metric system succeeded in taming most such
problems, as is evidenced in the fact that today it is
officially employed by every nation except the United States,
Myanmar and Liberia. Napoleon Bonaparte was not being entirely
hyperbolic when he said, in praise of Delambre and Mechain's
accomplishment, ''Conquests will come and go, but this work
will endure.''
BUT Alder is also sympathetic to the anti-metric concerns
of the ancien regime, where measurements often ''reflected the
quantity of labor a person could do in a given period of
time.'' Many working people regarded the imposition of an
abstract, external system as favoring the landlords by
divorcing the processes of tilling and harvesting from the
actual effort these tasks required. Their pleas were as
heartfelt, if as ill fated, as today's demonstrations against
global trade, and Alder gives them a fair airing. In this and
many other ways, his book passes a central test of any popular
work of history: it bathes the past in the light, life and
humanity of the eternal present.
Timothy Ferris's latest book is ''Seeing in the Dark: How
Backyard Stargazers Are Probing Deep Space and Guarding Earth
From Interplanetary Peril.''
