The steam locomotive chugged its way toward Cambridge,
Massachusetts, on August 15, 1859. On board was an impatient young scientist
wanting to understand the math and science governing how river channels should
behave. After disembarking at Harvard College and searching the stacks of its
library, Henry David Thoreau checked out “Principes D’Hydraulique,”
a three-volume tome of hydraulic engineering.
Once he translated and transcribed 17 pages from the
original French, he finally discovered what he was looking for: an equation for
the equilibrium velocity of a stream, given its shape, slope, volume of flow
and bed roughness.
This theoretically
minded, quantitative side of Thoreau is nearly invisible in the
cultural zeitgeist. There, his other side dominates: the famous 19th-century
transcendental nature writer, philosopher, social critic and abolitionist who
lived for two years in a small house in the woods above Walden Pond in Concord,
Massachusetts.
This literary-minded, qualitative Thoreau is canonized
and mythologized for “Walden,”
a foundational text for America’s environmental movement, and for “Civil
Disobedience,” which describes a model of nonviolent political protest
later adopted by Emma Goldman, Mahatma Gandhi, Martin Luther King Jr. and many
others.
Removal of this low factory dam across the Concord
River in Billerica, Mass., was the center of contention for what may have been
America’s first major environmental assessment.
The nearly invisible Thoreau – the compulsively
quantitative and analytically rigorous physical scientist – emerged from my
research as a geologist interested
in the history of 19th-century science. With two decades of scholarly books and
articles behind me, I’m now featuring this less well-known Thoreau in my
upcoming book, “The
Walden Experiments: The Science of Henry David Thoreau.”
Footnote to fame
Thoreau rose to fame as an original American thinker. He’s now the star of an award-winning video game. The Thoreau Alliance, an organization dedicated to educating about his life and legacy, is international. A recently released and highly acclaimed Ken Burns-Ewers brothers biopic, “Henry David Thoreau,” focuses on the usual side of Thoreau as a writer and activist, emphasizing his focus on environmental justice, sustainable living and the power of nature to heal our increasingly technological and frenetic lives.
Henry David Thoreau was a prominent 19th-century
naturalist, environmentalist and writer. Benjamin
D. Maxham/National Portrait Gallery
I served as an adviser for and appear in the film, which
touches on Thoreau’s science. These touches are limited mainly to his work as a
biological naturalist. Examples include his
pioneering insights on the dispersal
of seeds, his anticipation of Charles Darwin’s theory of natural
selection and his study of the seasonal manifestations of natural
phenomena, such as plants’ flowering times and bird migrations.
The fourth draft of a hand-inked table titled ‘Statistics
of the Bridges…’ about the Concord River, prepared by Thoreau as part of a
legal case in 1859. Courtesy Concord Free Public Library. Survey 133b.
Physical science
“I keep out of doors for the sake of the mineral,
vegetable, and animal in me.”
Thoreau wrote this entry in his journal on Nov. 4, 1852,
when he was busy researching the lake at Walden Pond. His words remind readers
that any search for meaning must ultimately begin with the bedrock roots of
their lives on which all plants, animals and cultures depend. My way of saying
the same thing is, “No
rocks, no ecosystems, no cultures.”
During his research on the lake and nearby streams,
Thoreau made an original discovery in fluid mechanics. On June 4, 1854, he
wrote the first known technical description of a standing capillary wave: a
small water wave that, instead of rippling outward, stays in a fixed position.
This phenomenon, which he later made a technical drawing
of, is now known as the Thoreau-Reynolds Ridge.
His co-discoverer, Osborne
Reynolds, was a pioneering Irish British hydraulic engineer.
Limnology and geology
Thoreau also pioneered limnology, the science of lakes.
He studied how light passed through the water of Lake Walden in liquid, solid
and vapor phases, how the lake stored heat in stable layers during the summer
and winter, how the water chemistry affected its clarity, and how lakes
eventually fill to become dry land.
His 1939 recognition as America’s first limnologist precedes
by two years his 1941 canonization as
an important American writer.
Thoreau correctly interpreted that his New England
landscape had been shaped by a colossal ice sheet that
had flowed southward from Canada. At the time, the state geologist of
Massachusetts and the American science establishment were incorrectly
attributing the same landscape to an iceberg-laden catastrophic flood. He also
correctly reasoned that his beloved Walden Pond was
born when a buried remnant of that ice sheet melted downward to create a
groundwater-filled sinkhole called a kettle.
He kept a growing reference collection of rocks and
minerals in his attic garret that was later exhibited for decades at the
nearby Fruitlands
Museum in Harvard, Massachusetts. His journal entries are peppered
with geological insights related to these specimens. His final journal entry is
a geological interpretation of rain splash erosion.
Thoreau’s river science
The most analytically rigorous science of Thoreau’s life
culminated with his 1859 research trip to the library stacks of Harvard
College. At the time, he was investigating how the Concord River watershed had
changed in response to the construction of a downstream factory dam a century
earlier.
Thoreau’s research was a clandestine part of a protracted
legal case involving four acts of the state Legislature between 1859
and 1862. Potentially, this was America’s first major environmental assessment
because it examined alternative actions to dam removal and weighed
environmental protection against socioeconomic costs.
During a span of 18 months, Thoreau carried out nearly 50
discrete research tasks to create dozens of tables of numerical data and a
detailed compilation map of the Concord River Valley that’s over 7 feet long.
His river
science predates that of the United States’ first recognized
river scientist by 18 years.
A colorized sequence of seven survey lines on a detail of
Thoreau’s draft bathymetry of Walden Pond. He was searching for its deepest
point. Courtesy Concord Free Public Library. Survey 133b.
The boldest claim of my latest book is that Thoreau’s
sharp swerve toward science in 1851-52 led to the rescue of “Walden,” his most
famous work. Specifically, his field research led to an understanding of its
namesake place as a natural system of water, air, land, aquifer and life that
included humanity. This more complex and inclusive vision transformed what had
been an abandoned draft of social critique into the nature writing that became
a foundational text for America’s environmental movement.
The Thoreau who built literary castles in the air put the
solid foundations of physical science beneath them.






