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Lambton's
trail started at
St. Thomas
' Mount through Tamil Nadu to
Hyderabad
, and from there on to Hinganghat |
The
longest measurement of the Earth’s survey ever attempted that also gave India
and her neighbors their maps
The
Great Trigonometrical Survey celebrated its 200th anniversary in the year 2003.
On April 10, 1802, Colonel William Lambton laid The Great Arc’s (the fond
sobriquet) first baseline at the hilltop of St. Thomas Mount in the then Madras,
now Chennai, capital of the southern Indian state of Tamil Nadu. Hailed as 'one
of the most stupendous works in the history of science', The Great Arc defined
Indian topography. This is the foundation on which all of India's infrastructure
- roads, the extensive railway network and telecommunications - are planned.
Begun
in 1800, The Great Arc was the longest measurement of the Earth’s surface ever
to have been attempted. Though Lambton initially planned a short arc, it grew to
be an unprecedented exercise. The Great Arc’s 2400 kilometers of inch-perfect
survey took nearly fifty years to complete. It cost more lives than most
contemporary wars, and involved equations more complex than any in the
pre-computer age. Rightly acknowledged by the distinguished Royal Geographical
Society of the United Kingdom as “the most significant contribution to the
advancement of science in the 19th century”, the survey is also the most
minutely accurate land measurement on record.
It
was also one of the most perilous endeavors undertaken by humankind. Through
hill and jungle, flood and fever, an intrepid band of Indian and British
surveyors carried the Arc from the southern tip of the Indian subcontinent up
into the frozen wastes of the Himalayas. With instruments weighing half a ton,
their observations were often conducted from flimsy platforms ninety feet above
ground or from mountain peaks enveloped in blizzards. Malaria wiped out whole
survey parties, while tigers, dacoity, tropical diseases, snakebites, local
resistance, battles and scorpions also took their toll. In the plains, where no
natural hills provided the elevation required for triangulation, 50 foot masonry
towers were constructed (they still exist!).
Irrefutably
Perfect
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The Great Arc was the longest
measurement of the Earth's surface ever attempted
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Says
the present Surveyor General of India, Dr. Prithvish Nag, the man helming a
renewed and enthusiastic effort to give the magnificent men behind The Great Arc
their due, “The path-breaking activities of the Survey came at a terrible
price and with immense effort. The scientific measurement of the country, which
was the survey’s primary task, had several ramifications. Surveyors had to
traverse from region to region, waiting for an opportune time, free from
man-made and logistic problems in order to continue with their efforts. The
information collected over the years with whatever technology then available
proved to be invaluable. The process has reaped rich results in that new
information packages, based on the latest technologies such as aerial
photography or global positioning systems (GPS), are able to benefit from the
data generated by those pioneers. No piece of information lies unused; all of it
has relevance even after decades. In fact, we crosscheck modern GPS results -
satellite mapping can be modified or tampered - with the Great Arc. The Survey
has played an invaluable role in the saga of India’s nation building. In spite
of sophisticated technology now becoming available, the accuracy of its
measurements remains undisputed. It is irrefutably perfect!”
The
precise data available from The Great Arc provided, for the first time in
history, accurately measured numbers required to calculate the ellipsoid of the
Earth. While it had been known for some 70 years that the Earth was more curved
at the equator and less at the poles, no data had existed to calculate this
curvature - until The Great Arc. The Great Arc also gave Bhutan, Myanmar,
Thailand, Tibet and Nepal their maps. This grand mission is accredited not only
for mapping of the entire Indian subcontinent, but also resulted in the first
accurate measurements of the Himalayas, an achievement which was acknowledged by
the naming of the world’s highest peak in honor of Col. Sir George Everest,
William Lambton’s equally worthy successor.
Revitalizing
a Wealth of Data
Even
as the Department of Science and Technology and the Survey of India announced
the yearlong celebrations to commemorate 200 years of the Great Arc, the
Surveyor General also launched a comprehensive programme to revitalize,
modernize and re-engineer the nation’s oldest institution, The Survey of
India, now in its 235th year.
In
a statement to the press Dr. Nag said, “The objective is to use the
bicentennial celebrations as an opportunity to leverage the enormous wealth of
data assets held by the Survey of India and convert them into knowledge products
to meet the rapidly growing needs of a knowledge dominated society. The Survey
of India intends to offer a wide range of products and services to meet the
geo-spatial information needs of Government departments, NGOs, infrastructure
projects, State Governments, Urban Local Bodies, Panchayats and other
community-based organizations, the private sector and the academia.”
While
it had been known for some 70 years that the Earth was more curved at
the equator and less at the poles, no data had existed to calculate
this curvature - until The Great Arc |
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He
added, “By making its existing data assets readily and easily available at an
affordable cost, massive cost savings can be achieved by organizations that
presently have to invest substantial resources in acquiring and generating data
which already exists. In this context, the initiative of Survey of India and the
Department of Science and Technology to create a National Spatial Data
Infrastructure (NSDI), in collaboration with the Department of Space, is of
special significance. The creation of the NSDI will be of revolutionary
importance, bringing together vast assets of major data producing agencies of
the Government - the SOI, the Department of Space, the Water Commission, the
Census etc. - into a common framework of standards on an Internet platform to
form a virtual infrastructure for providing universal access to standardized and
quality controlled information.”
Dr.
Nag also emphasized, “The NSDI will act as a clearinghouse of geo-spatial
information especially by making centralized ‘meta-data’ (i.e. data about
data) available on the Net and enabling any user to access the data held in the
distributed network and discover, explore and exploit the data for adding
further value to it. The beauty lies in the fact that such a virtual
infrastructure requires a minimal of financial investment well within the
budgetary resources of the agencies concerned, because it leverages the data
assets already held by the data producers and converts it into knowledge wealth.
In a situation where geo-spatial information is an engine of economic growth,
particularly through infrastructure growth, the economic significance of such a
data infrastructure is momentous.”
Professor
V. S. Ramamurthy, Secretary of the Department of Science and Technology added,
“The Great Trigonometric Survey can be considered as a foundation of all the
topographical surveys. The endeavor not only has a massive contribution to all
the topographical surveys ever conducted in the country, but also has a huge
impact on the development of science and technology today. It is possible to
claim that much of India’s infrastructural development, railways, national
highways, telephone lines and power-grids as well as defense, military and
strategic needs could not have been met without the accurate maps which the
measurement of the Great Arc made possible.”
Lambton
and Everest: Their Forgotten Quest
A
special word on Col. William Lambton is particularly due. In the summer of 1802,
while fellow British officers explored ways to escape the heat, Col. Lambton, a
mild and patient Yorkshireman, made plans to walk the heart of a steaming land.
On April 10, he carefully laid the baseline of about 7½ miles for the
measurement of length of a degree of latitude along a longitude in the middle of
peninsular India, at St. Thomas Mount in Madras. Lambton was part engineer, part
mathematician and astronomer, but his passion was geodesy, the study of the
Earth’s shape. Indeed, the zeal and zest with which Col. Lambton went about
his task had little to do with military expediency but a great deal more with
the quest for knowledge. After years of high-risk travel, ingenious
improvisation and awesome dedication, Lambton died in central India at
Hinghanghat (near Nagpur) in a Surveyor’s tent. The unfinished task was
completed by his successor, another great surveyor, George Everest, who
discovered and after whom the then anonymous Peak XV was named the tallest
mountain in the world.
Yet
today, they are utterly forgotten. Lambton is not even among the fifteen
thousand worthies named in the Chambers’ Biographical Dictionary. Everest is
just a mountain. In a country that regularly names streets and localities after
temporarily elected politicians, The Great Arc and its magnificent creators have
been consigned to oblivion. However, recent efforts have served to restore their
sterling distinction in small measure. The Survey of India has raised money to
restore and maintain Lambton’s neglected and dilapidated grave in Hinghanghat.
A well-endowed Chair for Geo-Spatial Studies has been instituted in Chennai’s
premier Anna University to “inspire the coming generations of geospatial
scientists to meet the challenges of the future.” Seminars, exhibitions (one
is currently touring the United Kingdom), valedictory functions, treasure hunts,
felicitations, press interfaces and film shows have been organized in many parts
of India. The Survey of India fulfilled its “long-held desire” to have an
office in Chennai, “the place where it all began”, as Dr. Nag puts it. A
paper on mapping the neighborhood with school children, a project launched by
the Survey of India as part of the bicentennial celebrations, won the first
prize at the Cambridge Conference, a congregation of the world’s Surveyors
General that takes place once in four years and was held in July last year. A
resolution was passed to emulate the Indian example.
Charting
History
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Lambton’s Great Theodolite
weighed half a ton without packing and needed more than 12 coolies to port it.
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A 100 ft chain was used by Lambton to measure the first baseline. This British
made chain was intended for the Emperor of China but by circumstance ended up in
the possession of a Dr. Dinwiddie, who then sold it to Lambton. The chain was
stretched 400 times to cover a distance of 7½ miles (12 km), the first baseline
commencing from St. Thomas Mount in Madras. Each time it was spread in its
special housing, leveled, aligned with elevating screws, and anchored against
the high winds. Because metals expand, a new chain was kept as a standard and
elaborate expansion tests were conducted regularly.
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Moving down the coast to the Cauvery River, the survey ran out of mountains.
However, Lambton discovered another type of rock formation: the magnificent
gopurams (domes) of carved rock temples, which tower over endless waves of
coconut palms. Winches, hoists and ropes were brought in. The sensitive,
delicate Great Theodolite was exalted to the supreme position on the temple’s
towering pinnacle. Then, at the world-famous Raja Raja Chola’s Brihadeswara
Temple (Periya Kovil or Big Temple), the holding rope broke. The Theodolite
slammed against a rock and its finely calibrated circle was destroyed. Lambton
picked up the pieces. Retreating to a tent in the ordnance establishment in
‘Trichinopoly’ (now Tiruchinappalli) and forbidding entry to all except
technical assistants, he reinstated the theodolite in six weeks, restoring it to
its former accuracy.
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Lambton’s Great Theodolite weighed half a ton without packing and needed more
than 12 coolies to port it. Commissioned especially from Cary of England, its
calibrations were so fine that they had to read through the microscopes fitted
on each circle. As the theodolite was being shipped to India, the ship carrying
it was captured by the French who were competing for territory in the East with
the British. However, once the authorities realized what it was, the theodolite
was released “in the interests of science”, repackaged and forwarded to
India.
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The average Survey train was impressive. For operations in 1841, Everest led a
huge cavalcade of 16 assistants, an armed escort of about 60 men, two native
doctors, 350 khalasis or handymen, 100 servants and followers, 6 elephants, 115
camels, 50 horses, 100 bullocks and cows, and 25 donkeys. An establishment of
this nature put tremendous stress on local resources. The impoverished village
bazaars were no match for appetites. Water, food and medical aid were scarce.
The privations were extreme. Adversities increased manifold when surveying
parties moved away from the base camp, completely isolated for weeks on end.
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Nain Singh used this compass and
prayer wheel to record survey information for a map of the Tibet
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There is no elevation on Earth than can compare with Tibet. The topography is
unique, of different tablelands separated by inaccessible mountain chains. In
1850, Tibet was completely sealed by the edict of the Chinese emperor. The
challenge of mapping Tibet under cover was taken up by Nain Singh, a school
teacher, one of the many brilliant ‘pundits’ recruited by the British to
facilitate ‘The Great Game’ (the mapping of the subcontinent’s sensitive
territories). In the guise of a lama, armed with a 100-bead rosary (the usual
number is 108) and a prayer wheel, Nain Singh took two thousand measured steps
to chart a mile. Over 21 months, he surveyed a 2000 km trade route, took 31
latitude fixes and determined elevations at 33 places. Among the other
‘pundits’ was Hari Ram, who gave descriptions and data on 48,000 km of
Tibet. Kishen Singh surveyed Tibet’s Nyenchitanglha mountains and China up to
the headwaters of Mekong, Salween and Irrawaddy rivers. The pundit, Kinthup,
sent to act as the servant of a Chinese lama but instead was enslaved in a
fairy-tale like saga, adamantly continued on his virtually suicidal mission and
sorted out the confounding and till then unconfirmed riddle that the Brahmaputra
and the Tsangpo were one and the same river.
Lalitha
Sridhar is a Chennai-based freelance journalist keenly interested in
development issues. Your emails will be forwarded to her by contacting the
editor at: ScienceTech@islam-online.net
