the struve geodetic arc & its future possibilities of being the one

NICE-SCEE-NUST-H-12,

ISLAMABAD

SECTION-B

11/15/2012

“Future Possibilities of Being the One and Only Arc Measured from Arctic Sea to Antarctic Ocean”

MEMBERS:-

ASAD ULLAH MALIK

MUHAMMAD AQIB USMAN

MUHAMMAD AWAIS ARSHAD

SAAD TARIQ

AAKIF SAEED

AMMAR MALIK

“Future Possibilities of Being the One and Only Arc Measured from Arctic Sea to Antarctic Ocean” 2012

1 Nov. 15, 2012

TABLE OF CONTENTS

INTRODUCTION OF STRUVE: ___________________________________________________________ 3

STRUVE GEODETIC ARC:- ______________________________________________________________ 4

a) Introduction: __________________________________________________________________ 4

b) Measurement: ________________________________________________________________ 6

1) The Great French Revolution: _________________________________________________ 7

2) The Need For Such A Measurement: ___________________________________________ 8

3) First Moves In Russia: _______________________________________________________ 9

4) Struve And His Colleagues: __________________________________________________ 10

5) Selection Of The Route: ____________________________________________________ 10

c) The Field Work: _______________________________________________________________ 11

1) Details Of The Field Work: __________________________________________________ 14

i) FIRST PHASE: Central West Russia (1816-1831):- _____________________________ 14

1816: _____________________________________________________________ 14

1820-1821: ________________________________________________________ 14

1822 – 1827: _______________________________________________________ 15

1825-1827: ________________________________________________________ 15

1828: _____________________________________________________________ 15

ii) SECOND PHASE: Extension To The South And North (1830-1844):- _______________ 16

1831: _____________________________________________________________ 16

1833: _____________________________________________________________ 16

1835: _____________________________________________________________ 17

iii) THIRD PHASE: Sweden And Norway (1844-1851) And Bessarabia (1846-1851):- ____ 17

1844: _____________________________________________________________ 18

1845: _____________________________________________________________ 18

1846-1850: ________________________________________________________ 18

1850 May: _________________________________________________________ 19

1851: _____________________________________________________________ 19

1852: _____________________________________________________________ 20

iv) FOURTH PHASE: Completion (1852-1855):- _________________________________ 20

1852-1855: ________________________________________________________ 20

d) Instrumentation: ______________________________________________________________ 20

e) Monumentation: ______________________________________________________________ 21

f) Units And Standards Of Length: __________________________________________________ 23


2 Nov. 15, 2012

g) Baselines: ___________________________________________________________________ 24

h) Reference Meridian: ___________________________________________________________ 26

i) Coordinates On The Struve Arc: ___________________________________________________ 26

j) Accuracy: ____________________________________________________________________ 29

k) Summary: ___________________________________________________________________ 30

l) Subsequent Comparison: ________________________________________________________ 34

m) UNESCO World Heritage: _______________________________________________________ 34

The Arc of 30th Meridian: ____________________________________________________________ 38

a) Introduction: _________________________________________________________________ 39

b) Background: _________________________________________________________________ 39

c) Measurement: ________________________________________________________________ 40

1) 1908-1909 (2º Arc In Uganda): _______________________________________________ 40

2) 1800-1930 (In Egypt): ______________________________________________________ 42

3) 1935-1950 (In Sudan): ______________________________________________________ 44

4) 1952-1954 (Closing The Gap In The Arc In Uganda And Sudan): _____________________ 47

Possibilities Of Being The Only Arc Measured From The Arctic Sea To The Antarctic Ocean: _______ 53

a) Background: _________________________________________________________________ 53

1) Reconnaissance Of Otto Struve: ______________________________________________ 54

2) The Mediterranean Sea: ____________________________________________________ 55

b) Future: _______________________________________________ Error! Bookmark not defined.

1) Possible Routs For The Connection: _____________________ Error! Bookmark not defined.

i) Route Through Asia Minor: ________________________ Error! Bookmark not defined.

ii) Route From Poland To Crete: ______________________ Error! Bookmark not defined.

c) Crossing The Mediterranean Sea: ___________________________ Error! Bookmark not defined.

D) One And The Only Arc Measured From Arctic Sea To The Antarctic Ocean: ________________ 57

APPENDIX _________________________________________________________________________ 59

a) Tenner: _____________________________________________________________________ 59

b) Hansteen: ___________________________________________________________________ 60

c) Lindhagen: ___________________________________________________________________ 60

d) Maupertuis: _________________________________________________________________ 61

e) Selander: ____________________________________________________________________ 62

e) Svanberg: ___________________________________________________________________ 63


3 Nov. 15, 2012

INTRODUCTION OF STRUVE: Friedrich Georg Wilhelm Struve

was a German born Russian

scientist. He was born at Altona,

Duchy of Holstein (then a part of

the Denmark–Norway kingdoms)

on 15 April 1793. He was the son

of Jacob Struve (1755–1841).

Struve's father moved the family

away from the French occupation

to Dorpat in Imperial Russia to

avoid military service, equipped

with Danish passports.

Struve came to Tartu University as

a refugee from Altona to study

Philology in 1808 as his father had

recommended. Indeed, he graduated from the university with a gold

medal at the end of 1810.Then he decided to continue his further studies

in mathematics and physics. In 1813 Struve passed the qualifying exam

for the master's and doctor's degree. In 1812 when during summer he

was practising land survey with a 10-inch Troughton sextant, he was

taken for a French spy and was arrested by a Russian patrol and was

released on the clearance of the confusion but Struve lost a week's work.

From 1813 to 1820, he taught at the university and collected data at the

Tartu Observatory (Dorpat). The Tartu Observatory was founded at the

Imperial University of Dorpat as it was reopened in 1802 and building

was completed in 1810 on the Toome hill in Dorpat.The Tartu

Observatory (Estonian: Tartu Observatoorium) is the largest

astronomical observatory in Estonia. The old Tartu Observatory is

known internationally for its connection to Friedrich Georg Wilhelm von

Struve and the Struve Geodetic Arc, of which it is the first reference

point. The instruments were installed in 1814 by von Struve who

Friedrich Georg Wilhelm Struve


4 Nov. 15, 2012

subsequently started observations. In 1820 became a full professor and

director of the observatory. In 1839, he founded and became director of

the new Pulkovo Observatory. The points of the triangulation chain

were protected and marked by cairns, commemorative plaques or

obelisks.

In 1827 he was

awarded their

Royal Medal and was elected a

member of

the Royal Swedish

Academy of

Sciences in 1833.

He died on 23

November 1864 in

Pulkovo, Russia.

STRUVE GEODETIC ARC:-

a) Introduction: It is a concept that started in the year 1816 and was

carried out by an astronomer by the name of

Friedrich Georg Wilhelm von Struve. During the

time of Struve’s existence, the distance between

two points was measured by measuring poles.

However in order to accomplish the goal that Friedrich von Struve had

envisioned - calculating the size of the earth - measuring poles would

not be sufficient. To do this a more sophisticated tool would be needed.

Before long the Struve Geodetic Arc was created to do just that.

The Struve Arc only ran through two counties, namely Russia and

Sweden-Norway. But his surveys, that took place between the years of

1816 and 1855, calculated the very first measurement of a part of the

Pulkovo Observatory, Russia


5 Nov. 15, 2012

meridian with staggering accuracy. It was the start of topographic

mapping and a growing interest in earth sciences. The Struve Arc is a

survey triangulation chain which has assisted scientists to map out

certain areas and regions of their countries. The Struve Geodetic Arc is

currently a joint venture between scientists of various countries who

work together in the name of science. Today the Struve Arc survey chain

runs through ten countries, namely Norway, Sweden, Lithuania,

Moldova, Russia, Latvia, Belarus, Ukraine, Finland and Estonia, and

stretches from Hammerfest (Norway) to the Ukrainian Black Sea.

The Struve Geodetic Arc is a chain of survey triangulations stretching

from Hammerfest in Norway to the Black Sea, through ten countries and

over 2,820 km, which yielded the first accurate measurement of a long

segment of a meridian, helping in the establishment of the exact size and

shape of the world, and it exhibits an important step in the development

of the earth science. The chain was established and used by Friedrich

Georg Wilhelm von Struve in the years 1816 to 1855 to establish the

exact size and shape of the earth. At that time, the chain passed merely

through two countries: Union of Sweden-Norway and the Russian

Empire. The Arc's first point is located in Tartu Observatory, where

Struve conducted much of his research. All ten countries have been

working together to maintain the chain’s station points and to protect the

Struve Geodetic Arc. In 2005, the chain was inscribed on the World

Heritage List as a memorable ensemble of the chain made up of 34

commemorative plaques or built obelisks out of the original 265 main

station points which are marked by drilled holes in rock, iron crosses,

cairns, others. Measurement of the triangulation chain comprises 258

main triangles and 265 geodetic vertices. The northernmost point is

located near Hammerfest in Norway and the southernmost point near the

Black Sea in Ukraine.

In 2005, the Struve Arc was inscribed on the UNESCO World Heritage

List. This inscription is located in ten countries, the most of any

UNESCO World Heritage.


6 Nov. 15, 2012

b) Measurement: A long ongoing dispute in the French Academy of Science about the real

shape of the Earth ended in the 1730's with a victory of Newton's theory

which said that the Earth was not a perfect spheroid, but somewhat

flattened at the poles (ellipsoid). Scientists in the next 200 years tried to

get more accurate information about the size and the shape of the Earth

by meridian arc measurements. So did also the Russian scientist

Friedrich Georg Wilhelm Struve.

In 1812 when during summer he was practising land survey with a 10-

inch Troughton sextant, he was taken for a French spy and was arrested

by a Russian patrol and was released on the clearance of the confusion

but Struve lost a week's work. From 1813 to 1820, he taught at the

university and collected data at the Tartu Observatory (Dorpat). The

Tartu Observatory was founded at the Imperial University of Dorpat as it

was reopened in 1802 and building was completed in 1810 on the

Toome hill in Dorpat. The Tartu Observatory (Estonian: Tartu

Observatoorium) is the largest astronomical observatory in Estonia. The

old Tartu Observatory is known internationally for its connection to

Friedrich Georg Wilhelm von Struve and the Struve Geodetic Arc. The

instruments were installed in 1814 by von Struve who subsequently

started observations.

Around 1815 the Livonian Society of Public Utility and Economy

applied to the Tartu University for technical help in land survey. They

planned to issue a topographic map of Livonia (now the southern part of

Estonia and the northern part of Latvia. The university made a contract

with Struve who was then the extraordinary professor of mathematics

and astronomy. He was allowed to spend only three to four summer

months for this work. The contract foresaw that all the expenses would

be covered by the Society (approximately 3000 silver roubles) as

planned. Struve has been even given a horse and a wagon.


7 Nov. 15, 2012

The triangulation of Livonia – a big and exacting task for young and

inexperienced Struve - was carried out with flying colours. Struve

finished his triangulation in 1816. This was controlled by a baseline on

the ice of Lake Werz-Jerw, measured in 1819. The experience

accumulated during this work laid a solid basis for an enormous future

project (measurement of the big arc).

Struve intended to remeasure at least a part of the Livonian triangulation

network but instead of that he started a much bigger project

(measurement of the meridian arc of 25 degrees 20 minutes). The

observation were carried out in the years 1816 to 1855 and resulted in

establishing the exact size and shape of the Earth. Through the years

1816 to 1855 he managed the work on what previous was called The

Russian-Scandinavian Meridian Arc Measurements. It can be considered

as one part of his lifework. Until about 100 years ago it was the longest

meridian arc measured on the Earth.

When von Struve began assembling his Geodetic Arc in 1816, the

doorstep of the observatory became its first point. For the astronomical

source of the geodetic network Struve chose the university observatory

whose geographical coordinates he had measured for his doctoral thesis,

and the cathedral in Riga.

On the other hand work in the Vilnius district was initiated by Tenner in

1816(same year) for the purpose of mapping.

1) The Great French Revolution:

The seeds for the Struve Arc were sown by the Great French Revolution.

Many traditional habits were replaced by new systems. Especially old

measures were toppled by a new metric system.

A result from the French Revolution wars was raging all around Europe.

The Napoleonic wars stretched from the North Cape to Cairo and from

Moscow to Atlantic Ocean. The initial defeat of Napoleon resulted in the

Vienna Conference but in the middle of negotiations Napoleon made a


8 Nov. 15, 2012

"come back" and war broke out again. When Napoleon was finally

defeated by Russia, the Vienna Conference reconvened and agreed in

1815 on the international boundaries in Europe and on the steps to be

taken against the seeds of the revolution and against new uprisings.

At that time there was a general restlessness among the rulers in Europe.

They did not trust a lasting peace and tried to be prepared for new wars.

Mapping for such military purposes was a must and all steps to its

promotion were advanced.

2) The Need For Such A Measurement:

The lack of a proper framework for the topographic mapping was a

problem at that time. Such a framework could be likened to a human

skeleton upon which the flesh (or map information) is added. At the

lower order a method called framework traversing was available but the

higher order was more complicated. Astronomical observations were too

difficult at the density needed in traversing, especially for the

determinations of the longitude which was still a very difficult problem

to solve. In addition, the coordinate system required a resolution to the

uncertainty of earth ellipsoid dimensions. Especially in Russia both

needs were felt deeply; that of the fundamentals of geodetic surveys and

that for suitable map grids. Many professors in mathematics attempted to

foster new knowledge in these areas. Top military surveyors however

were interested only in better mapping. It was Colonel Carl Tenner who

managed to combine both needs in the triangulation work in Lithuania

started in 1816. Astronomer Wilhelm Struve's proposal to the Tzar of

Russia in 1819 also combined both elements.

Tzar Alexander the First, after defeating Napoleon and entering Paris

felt himself leader of European politics where science was fortunately

among the top priorities. Struve got all the resources he needed for his

project. The way was open for an arc measurement to develop the basis

of a geodetic framework and to start the topographic mapping.


9 Nov. 15, 2012

3) First Moves In Russia:

At about the same time that the Peru and Lapland arcs were being

measured Joseph Delisle published in 1737, a proposal for an arc to be

measured through the Russian empire and embracing some 22º of

meridian. He stated that "...this set of degrees when determined would

display in an incontestable manner, if their variations were uniform,

would show whether different meridians have different curvatures..."

Surprisingly the Empress Anne of Russia was not frightened by such a

vast proposal and gave it her backing to contribute to the progress of

science.

Unfortunately in 1739, after Delisle got as far in his triangulation as

measuring a base on the ice from Peterhof Castle in Kronstad to Doubni

Castle on the island of Retusri, and connecting the base to several points

by triangulation, a journey to Siberia in 1740-41 interrupted his work

and it was never restarted.

At that time the meter had yet to be developed and the base had actually

been measured at about 13.5 verstes (an old Russian unit of

approximately 1.067 km per verste or a base length of 14.4 km). The

measurement itself was by wooden bars of known length placed end to

end. Nothing was published on this work but in 1844 Otto Struve, son of

F.G.W. Struve, did come across Delisle's manuscript in the Paris

Observatory archives. For his angles Delisle talked of using a 30º sector

of 12-15 ft. radius and a quadrant of 2-3 ft. radius.

B.A. von Lindenau, Director of the Seeberg Observatory, proposed to

Prince Wolkonsky, the measure of an arc of meridian (or section of a

line of longitude) to follow the western provinces of Russia south from

the White Sea. He presented the proposal to the Russian authorities. This

did not progress because of a disagreement over which instruments -

German or Russian- should be used. Struve's opinion however was in

any case it was not a good site for well-conditioned triangulation.


10 Nov. 15, 2012

4) Struve And His Colleagues:

Around 1815 F.G.W. Struve, Professor of Mathematics and Astronomy

at the University of Dorpat was put in charge of a trigonometric survey

in Livonia. This was controlled by a baseline on the ice of Lake Werz-

Jerw, measured in 1819.

During 1820 Struve assisted Gauss in the base measure by Schumacher

made near Braack with his new Repsold equipment.

This work enabled Struve to interest officials in the idea of an arc of

about 3½º between Gögland, an island in the Gulf of Finland, and

Jacobstadt to the south. After getting the resources he was able to

observe the arc between 1821 and 1831.

During more or less the same period (1816-1828) Carl Tenner was doing

similar work further south in Lithuania but at that stage he was operating

quite independently from Struve.

Once he had completed his early surveys, Struve was keen to extend the

measurements further north and south so that a very long line would

result and could be the basis of a sound set of values for the earth

parameters as well as having other uses. He would have been aware of

the work at that time in India on the measurement of the Great Indian

Arc, and that it would be an ideal partner to anything he did through

Russia, to determine the earth’s parameters (As it is known that one arc

on its own is insufficient to determine the parameters of an oblate

spheroid).

5) Selection Of The Route:

It is little surprise, since Struve worked at Dorpat University, that he

decided any extensions of his surveys should follow, as nearly as

possible, the line of longitude (meridian) through Dorpat Observatory at

about 26º East of Greenwich. Looking at this line on a map it was clear

that some work had already been done in its vicinity in the far north (by

Maupertuis 1736-37; and by Svanberg 1802-03) from the northern end


11 Nov. 15, 2012

of the Gulf of Bothnia (north west of Finland) well into the Arctic

Circle. Here was an opportunity to connect to that work and further

extend the line. At the same time it became clear that Tenner was

working more or less along the same meridian towards the south. While

Struve could envisage the northward extension, Tenner similarly noticed

how there could be a southern extension as far as the Black Sea. Thus

the elements were present for an arc that stretched from Fuglenaes near

Hammerfest in the far north over some 2800 km (1750 miles) to Staro-

Nekrassowka near Ismail in the south over 25º of latitude. It was quite

natural that both Struve and Tenner assumed the astronomical positions

of Dorpat (Tartu) and Wilno (Vilnius) respectively, as zero meridians of

their independent surveys. Luckily these were close enough to enable a

trigonometric link. Then the observed latitudes and azimuths allowed

calculation of the longitudes to the other points in relation to the zero

meridians.

c) The Field Work: F.G.W. Struve started his work on his ambitious project in 1816 at The

Tartu Observatory. His aim was to establish a long arc of a meridian to

measure the exact shape of the Earth.

As far as is known there is no other such feature as the Struve Geodetic

Arc represented on the UNESCO World Heritage List so no direct

comparisons are possible. Worldwide there are a finite number of such

features that might be similarly considered and probably only 5 that,

should this nomination be accepted, rank as of anywhere near similar

importance. These are in India, Eastern Africa (from Egypt to S. Africa),

Peru, N. France to N. Africa and across Central Europe from Southern

Ireland to the Urals in Russia.

Due to the large variety of natural and political circumstances involved,

each country from the Arctic to the Black Sea presented unique

peculiarities in the work, at first glance, of a purely technical kind.


12 Nov. 15, 2012

The work on the Scandinavian sector was carried out by Swedish and

Norwegian experts, with the assistance of from Poulkova Observatory

and astronomers Karl Tenner, F.G.W. Struve, N H Selander and Chr. Hanste. They were the directors of the Poulkova Observatory.

Norway accomplished the most northerly arc measurement in history,

and the monument near Fuglenaes that marks this achievement is the

most beautiful on the Arc. Swedish surveyors attempted to make the

final judgment over the famous Tornea valley in Lapland being

measured for the third time! – Thus they measured their principal

baseline twice unlike the 9 other Struve arc baselines measured only in

one direction according to the usual practice of the time. The longest arc

segment in time and the second in length were measured through

Finland’s forests and swamps, where the large number of surviving

marks is in rock. The segment was also the best connection between the

monarchies of Russian Tsar and Swedish King who both contributed to

the work, thus have met at quite peaceful reason, though not in fact, on

the front page of the Struve final account, and acknowledged in solemn

texts on the extreme arc monuments as well. Estonia gave the origin of

the meridian to be measured for 40 years ahead, and famous Wilhelm

Struve started as astronomer and surveyor in this country. His Baltic arc

segment reached the Latvian river Daugava (Duna) and was connected

in the south with the arc segment of his friend general Carl Tenner, an

outstanding Russian surveyor, who worked in Latvia, Luthiania and

Belarus. Latvian fields presented the first connection of measurements

based on the Russian-English unit of the sajene (7-feet Tenner’s

standard) and the Russian-French unit of the toise (6-feet Struve’s

standard). The famous German astronomer Wilhelm Bessel judged on

this connection and later used the combined Struve-Tenner arc for

several derivations of the Earth’s reliable geometry. This laid the

foundation for the derivation of Bessel Ellipsoid (1841). In Lithuania

the longest baseline of 11.8 km was measured with an apparatus, which

was made by Tenner and some other observers, kneel down to read the

scales of the level, thermometer and contact sliding rule. Besides, a


13 Nov. 15, 2012

unique triangle side stretching exactly along the meridian line was built

in this country by Tenner to escape the complexity of orientation

(azimuth) observations.

In Belarus the first topographical works in Bessarabia were undertaken

by Russians in 1817-1819 and 1822-1827. Karl Tenner worked here

with F.G.W. Struve. Belarus presents a unique Struve-Tenner arc

survival with the authentic endpoints of the Ossownitza baseline.

Ukraine and Moldova present the longest arc segment, having entered

into the northern extremes of the Islamic world. However, unlike

Finland, the measurement took half of the time; it was due to the very

favorable topographical circumstances. F.G.W. Struve together with

Karl Tenner as geodesist headed triangulation explorations in Ukraine.


14 Nov. 15, 2012

Further research will possibly reveal the highest accuracy of

measurement achieved in this country. Additional search along this arc

segment, still little surveyed, may also provide other interesting finds.

Unfortunately, Struve’s suggestion of expanding the measurement

further to the south was not realized within the same century because of

political unrest in the region.

The work on the Russian part of the arc was carried out jointly by

Imperial staff officers, the Dorpat Observatory and the Central

Observatory of Poulkova. Karl Tenner’s and F.G.W. Struve’s work is of

high importance in this context.

1) Details Of The Field Work:

Struve reported the division of work on the arc in four phases

encompassing seven sections. The various phases of the arc

measurement are as follows:

i) FIRST PHASE: Central West Russia (1816-1831):-

1816-1820:

The early work by Struve had baselines

measured with wooden bars and angles by

Troughton sextant yet even so he got good

results. In 1817 Colonel Tenner who was the

previous year charged with the trigonometric

survey in western Russian Provinces obtained

the permission (without funds) to also carry out

an arc measurement along the Vilna meridian

and started it.

1820-1821:

Struve obtained a grant from Dorpat University

to fund further arc measurement including

development of his own form of base line

Northernmost Point

of The Struve Arc


15 Nov. 15, 2012

equipment. He consulted with Schumacher, Bessel and Gauss, and

decided to adopt the observing method used by Schumacher on the arc

between Denmark and Hannover. He took his reconnaissance

northwards from Gogland Island into Southern Finland together with H.

Walbeck, and investigated the country south from the Gulf of Finland.

1822 – 1827:

Struve fitted surveying observations in between his lecturing duties and

observing in Dorpat Observatory. Professor Paucker from Mitau

(Elgava, Latvia) helped with the astronomical observations at Jacobstadt

and Gögland. Struve has crossed the larger part of the Gulf of Finland

although the connection was difficult: the longest side of the arc

triangles he observed from Gögland to the southern shore of the Gulf. In

1827 the chain from Gögland to Jacobstadt (Jekabpils) was completed,

but whilst building substantial signals there were no rocks in which to

leave bolts to mark the positions. When measuring the Simonis base in

October 1827 the temperature fell to -13ºR = -16ºC.

ºR = Rankin degrees ºR = ºF (Fahrenheit) + 460º

1825-1827:

Tenner’s responsibilities extended into Belarus. He had completed a

chain along the meridian of Wilna from Belin to Bristen tied to baselines

at Ossownitza and Ponedeli. As a result Tenner’s most northerly point

was then only 32 km west of Struve's most southerly station.

1828:

The possibility of joining the two arcs brought Struve and Tenner

together in Dorpat possibly for the first time. They were to fight the

challenge of incomparability of their two very different units of length

before connecting both chains.


16 Nov. 15, 2012

Struve and Tenner managed to solve all the problems, and as a result by

1831 there was an arc of 8º 02.5' from Gogland to Belin equipped with

three base-lines and five astronomical stations with latitude and azimuth

observations. The results of the connecting of the two partial arcs were

published by the Academy of Sciences in its Memoirs of 1832 and also

in volumes VIII and X of the Annals of deposit topography in 1832. It

was soon used by Bessel who until 1841 was engaged in computations

of improved values of the earth dimensions.

ii) SECOND PHASE: Extension To The South And North

(1830-1844):- This began with Struve requesting resources from the Tsar Nicholas I to

extend northwards to Tornea. The idea was to connect with the earlier

work of Maupertuis and the extension of that by Svanberg.

The military (not only Russian) also had the idea of connections, and

Tenner secured three (in 1832, 1843 and 1853) between his, the Prussian

and the Austrian geodetic networks, here from to France and the British

Islands. This was the first major in transcontinental European East-West

geodetic framework.

1831:

Struve obtained permission to extend northwards and connect with the

Lapland arc. Angular measurements were performed by three Finnish

officers who had been educated at Dorpat.

1833:

In 1833 Struve was commissioned by Nicholas I to build the best

Russian astronomical observatory at Pulkovo.


17 Nov. 15, 2012

1835:

The work was mostly led by a Finnish astronomer Woldstedt, as the

officers had been called off for other Russian surveys. Meanwhile

Tenner was continuing his geodetic work south of the River Pripyat

passing through parts of the Ukraine. His new baseline at Staro-

Konstantinow was among the longest in the whole arc. Astronomical

observations were made at Kremenetz (latitude 50º 06') and

Suprunkowzi (latitude 48º 45').

iii) THIRD PHASE: Sweden And Norway (1844-1851) And

Bessarabia (1846-1851):- Struve had a more complicated task. The first leg across autonomous

Finland was not politically difficult. Moreover, he could leave the

practical implementation to Woldstedt. Later political steps were needed

and the necessary agreements made.

The chain was joined in the north to that part carried out by Sweden as

their share. In Sweden the responsibility for the work was given to the

astronomer N. H. Selander.

There the chain followed first the old Maupertuis arc of 1736, with

western points on the Swedish side and the eastern ones on the Finnish

side of the boundary.

Continuing further to the north there was a new political problem that

Norway belonged to the Swedish realm but had her own administration.

Consequently, the rest of the chain from Atjik to the Barents Sea was

measured under the responsibility of Christopher Hansteen (1784-1873)

Director of the Royal Norwegian Geographic Department, as far as the

northernmost point at Fuglenaes. This finished the fieldwork.

The northern part included 4 additional astronomical stations and 4 base

lines.


18 Nov. 15, 2012

1844:

Struve conferred with scientists from Norway, Sweden and Russia as

well as with Tenner, on the possible extension southwards to the Black

Sea and for a northern extension to the Arctic. Commissioners were

appointed to assess the feasibility by Sweden from Tornea to

Kautokeino and Norway and Norway from there to North Cape.

Later the same year Struve met with King Oscar I and proposed the

extension to the Barents Sea. This was quickly agreed and N.H. Selander

from Sweden was made responsible.

A baseline was measured near Elim (latitude 60º 50').

1845:

Norwegian participation was put in the hands of Christopher Hansteen.

Astronomical observations were made near Tornea (latitude 65º 51'). A

further base was measured at Oulu (lat. 65º 00').

This then allowed a readjustment of the chain from Tornea to

Ssuprunkowzi, an arc of 17º 05' 33''.

In 13 June an agreement was made between Sweden and Norway for the

arc to begin. Hansteen dispatched two young officers to reconnoiter(to

make a military observation) the area, build signals and determine

suitable sites for the baseline and astronomy.

1846-1850:

In Bessarabia Tenner continued the triangulation chain as far as the

fortress at Ismail, located near the mouth of the river Danube. Two more

baselines were measured and two astronomical stations completed. He

terminated in the village of Staro-Nekrassowka (latitude 45º 20').

Measurements of the Meridian Arc in the territory of Moldova started in

August 1846, within the general triangulation frame of “Bessarabia


19 Nov. 15, 2012

Region”. General management was provided by Lt. Gen. Tenner,

operational management by Lt. Col. Heldenbrand, and from August

1847 by First Lt. Napersnikov. Measurements of Moldovian points were

completed in 1848. The whole triangulation of this area, including the

surveying of the southern part of the meridian arc, is founded on two

baselines: Romankauti and Tashbunar, both are in Ukraine and were

surveyed by means of the Struve base equipment. The first of them was

adjacent to the border between Moldova and Ukraine and the Moldovian

line Gvozdauti-Briceni. Astronomy was provided by Pulkovo

astronomer Sabler at the point Vadul-lui Voda in September 1848.

1850 May:

The Alten base was measured by Klouman (1813-1885) and an

astronomer, Lindhagen, from Struve's staff at Pulkovo. The area was flat

but the base was only 1154.7 t. (2251.7 m). Each terminal was

monumented with a stone block, and small iron bolt at the center.

Bad weather severely delayed the astronomical observations at the

northern terminal of the whole arc, Fuglenaes near the town of

Hammerfest, and Lindhagen just managed to get the last boat south

before the permanent winter dark set in.

Unfortunately his assistant Lysander died on the long journey back to

Pulkovo.

There were 15 stations between Hammerfest and the Swedish border

near Kautokeino. The astronomy was at Fuglenaes because North Cape

itself was unsuitable for the final station because of the weather

conditions and persistent fog.

1851:

A baseline was measured near Tornea and the astronomy completed at

Stuor-oivi.


20 Nov. 15, 2012

There were 24 stations in the Swedish section which was mostly

observed by Selander, Lindhagen, Skogman and Wagner.

1852:

The base extension of the Öfver-Tornio (Ylitornio) was completed.

iv) FOURTH PHASE: Completion (1852-1855):-

1852-1855:

Some supplementary re-

observations of suspect values

were made during this period.

To honour the completion of

the arc, monuments were

erected at Staro-Nekrassowka

and Fuglenaes.

d) Instrumentation: Struve used a universal instrument (theodolite) by Reichenbach of

Munich which had a 13 inch diameter horizontal circle and 11 inch

vertical circle. These were graduated to 5' (= minutes of arc) and read

directly by verniers to 4" (= seconds of arc).

Tenner used a variety of seven instruments by a range of different

makers. There were two repeating circles, one of 13 inches diameter by

Baumann, which read to 4" by vernier, and the other 14.3 inches by

Troughton reading by vernier to 10''. A 12 inch diameter terrestrial

repetition theodolite by Reichenbach read by vernier to 4'' an 8 inch

astronomical repetition theodolite by Ertel reading to 10"; a repeating

theodolite of 10 inches made in the Etat-major and reading to 5''; and

The Southernmost Point of The

Struve Arc


21 Nov. 15, 2012

two instruments by Ertel. The first two of these instruments gave

inclined angles whilst the other five used by Tenner and that by Struve

gave horizontal angles direct.

e) Monumentation: Another remarkable item of the Struve arc is the monumentation of the

stations. In Finland many were marked on the solid rock by drilling a

hole. The hole was filled with lead and on the top of the lead was a plate

of brass. Veriö elaborated this point saying that nearly all stations

between Hogland and Tornio were marked with small copper plates,

which were soldered with lead into 5-7 cm deep holes drilled in the rock

or big stones. In the course of time most of the plates have disappeared.

In fact most of them were found missing already in the 1890s. Later the

lead has been dug out, maybe to be made into shot for the hunters.

However, nobody has been able to take along the holes in his pockets. In

the Swedish-Norwegian part many points were marked directly on the

solid rock or on big rocks by engraving a cross and are still unchanged.

Unfortunately, Struve did not leave ground markers to mark the

positions of his stations between Gögland and Jacobstadt (Ekabpils,

Latvia), except for the two terminals. Within this section the center

markers were mostly placed on timbers, which have not survived. The

monumentation south of Jacobstadt belongs exclusively to the merits of

Tenner.

There points were marked on stones or brickwork, which were placed

underground to depths of up to a meter.

In general the form of the marks can range from:-

- A small hole drilled in a permanent rock surface - sometimes filled

with lead but often such a filling has been poached for other uses

although the hole remains.

- Cross shaped center and/or witness marks engraved in the rock.


22 Nov. 15, 2012

- To a solid block with a marker set in it.

- Or a large solid structure of rocks possibly some decimeters below

ground level together with a center stone or brick in which there is a

drilled hole.

- A measuring block on top of which was a single brick on edge of

which the intersection of the diagonals designated the point. This was

used by Tenner on his baselines. Essentially the marks are similar to,

and serve the same purpose as, the triangulation pillars that one finds on

hill tops in the many countries where there is a central mark within some

larger, stable and reasonably secure structure. With the older marks

these are now sometimes found 25 cm or more below ground level but

on location, excavation and verification are still in their original

condition.

A special form of conservation is proposed for the selected Struve

Geodetic Arc stations: i.e. special plaques or similar notice boards in the

immediate vicinity. Existing linear cultural sites bear a description

distributed along the lines and this is also envisaged in the case of the

Arc points.

The lengths attainable between neighbouring triangulation points vary

according to several factors. These include the range of height of the

topography, the vegetation cover and the suitability of points to form

reasonably shaped triangles. For the full Struve Arc the longest line is

81.7 km in length (from Mäki-Päälys on Hogland Island to Halljall in

Estonia) and many lines are well over 60-70 km long. The shortest line

is only 479.6 m in length (from Porlom 1 to Porlom 11 in Finland). The

average length between points is 27.1 km.

None of the terrain over which the survey was observed could be termed

mountainous as in the Peru arc of 1735 (along the Andean peaks) or the

Arc of 30th

Meridian (the mountains of East Africa). However the terrain

varied from massive granite outcrops in the Northern latitudes, some tree

covered, through low lying areas in central Finland. To the simple island


23 Nov. 15, 2012

of Hogland that greatly assisted the crossing from Finland to Estonia but

presented poor geometry. Through thickly forested areas of Eastern

Europe and the marshlands to the delta of the river Danube where long

sight lines were difficult to obtain. Any hills were made use of as well as

high buildings available like the tower of Alatornio church and the

Observatory at Tartu.

Many chains were measured in different continents in subsequent years.

Some results of these activities can be seen in the development of the

computed dimensions of the earth.

f) Units And Standards Of Length: Although at the time of the surveys, the metric system was well

established, the base measurements were recorded in two different units

of length. Struve used the old French "toise" (approx. 1.949 m) because

his basic standard had come from France.

Meanwhile Tenner used the Russian unit the "Sajen” (approx. 2.134 m)

because his basic standard had been built in St Petersburg based on

English "foot”, as in the 18th century 1 sajen was defined equal to 7

English feet. The two units first "met" or came together on the Struve

arc of the meridian. By 1830 Struve and Tenner had solved the problem

of converting sajens into toises through careful examinations of their

measuring bars and the respective standards, and Struve was able to

present further results in toises. His final table of the length of the arc

segments is computed in those units, probably for the last time in history

and probably also as a sign of the merits of Frenchmen in measuring the

earth.

Some complications later occurred when trying to determine the best

conversion factor for relating the toise to the modern metre. Various

factors will be found ranging from 1.949 to 1.949 087. Of course, with

the long distances that occured in this project the last digits can make a

significant difference.


24 Nov. 15, 2012

The standard unit used was the toise of Paris, which was the same as the

toise of Peru. Copies were specially commissioned by Struve and Bessel

and constructed by Fortin. From his copy Struve had two field standards

made each of about 2 toise or 1728 lignes long. (1 ligne = 1/12 inch).

Tenner on the other hand used a standard of 945 lignes, which equates to

the Russian sajène or 1.0946 toise. During 1850 to 1853 ninteen (19)

different standards were inter-compared at Pulkovo. Thus the

relationships become complicated.

That used on the baselines of Simonis, Elim and Oulu was of

1728.01249 lignes of the Fortin toise at l3ºR. For the bases at Alten,

over Torneå and Taschbunar the standard was of 1727.99440 lignes. For

the Romankautzi base the standard was of 1728.01991 lignes. The value

of Tenner’s standard, used for the bases at Ponedeli, Ossownitza and

Staro-Konstantinow was of 945.75779 lignes.

g) Baselines: Sprinkled among the 258 principal triangles were 10 baselines, three of

which were measured with Tenner's apparatus and seven with that of

Struve. The Struve equipment consisted of four wrought iron bars each

of 2 toise in length. One end of each bar had a small cylinder with

slightly rounded end; the other end of each had a contact lever which

was pivoted to the bar. Two thermometers were set into holes in the bars

and the bars were each set in boxes from which their ends protruded.

Seven of the baselines were measured using this equipment and Struve

estimated the probable errors of each to be around 1 ppm.

The other three baselines were measured by equipment devised by

Tenner. Here the bars were of forged iron 2 sajènes long. One end of

each bar was fixed and the other free to move. At this latter end was a

sliding scale that could be used to determine the distance between

consecutive bars. Struve estimated the probable errors of Tenner's

apparatus to be around 3ppm. With a single exception, all the baselines


25 Nov. 15, 2012

were measured in one direction only, thus control over the lengths of

sides connecting successive arc segments was essential.

The last column of the following table gives the quoted accuracy when

computing from one baseline to the next which is not the same as the

accuracies of the individual baselines.


26 Nov. 15, 2012

h) Reference Meridian: Struve was working in Dorpat (now Tartu)

Observatory and so it was logical to select

the meridian line through that place as a

reference line. It was taken as the start

(datum) point in both latitude and longitude.

Distances were calculated N and S of Dorpat

with Dorpat as 0, reaching 710 000 t to the

north and 740 000 t to the south.

Details are given in at the location of the

reference point under the center of the

Cupola of the observatory. The point was

relocated from Struve’s original measurements and is now marked with

a 12 mm bronze marker and a commemorative plaque unveiled in 2002.

i) Coordinates On The Struve Arc: Due to his incurable illness diagnosed at the beginning of 1858, Struve

never managed to publish the 3rd volume of his Arc du meridien…. A

full account of the astronomic operations, final results, a critical

evaluation of the world arc measurements and derivation of a series of

related earth figure parameters would have been contained there.

Perhaps, a full list of geographic coordinates of all the arc stations was

also kept in mind for use by the Russian Army General Headquarters

that shared the arc field operations from the very beginning in 1816.

Such a full list was not computed until 1926.

Before that time some Russian regional nets did include Struve arc

stations, with subsequent derivation of their coordinates. For instance, in

1892 the Head of the Russian Survey of Finland Lieut. Gen. Järnefelt

published a list of geographic cords of 91 stations of the northern part of

the Struve arc from Gogland (Mäkipäällys) to the Norwegian border

(Stuoroivi). The values were computed on the 1819 Walbeck ellipsoid

with longitudes related to Dorpat meridian. In 1926 a vast list of

Tartu Observatory


27 Nov. 15, 2012

coordinates of the Russian 1st order triangulation points was published,

including Struve arc Russian stations south of Kakamavara (near

Tornea) to Izmail, that resulted from computation on the 1841 Bessel

ellipsoid, the longitudes being related to Pulkovo.

Both the Lists were in the Proceedings of the Russian Military

Topographers Corp (in Russian). Since then, due to the collapse of the

Russian Empire and subsequent political changes in Eastern Europe,

there have been no other computations for the entire arc although there

have been separate calculations within national borders (Latvia, Finland,

Norway, Poland, Romania).

Observations for latitude and azimuth were made at 13 selected stations

3 of these were in Scandinavia and the other 10 in the Russian Empire

states. This gave 12 arcs (see the Table in the topic Accuracy) varying

from 1º 22' to 2º 54' in length that could be computed separately.

From these the length of 1º (see the Table “Length of 1 º) was

determined for each of the 12 arcs and these varied from 57 252 t in the

far north to 57 068 t in the far south but there were some inconsistencies

in between. Using seven different divisions there was a more regular

decreasing pattern between similar extreme values. A decrease as one

moves from north to south indicated an oblate rather than a prolate shape

for the earth.


28 Nov. 15, 2012

The results of the 1816-1855 arc measurements were first published by

W. Struve in 1857 (unfortunately, without astronomy and the historical

preface), then in 1860 (in full) each edition in French. In 1861 an

identical Russian edition was issued and some selected chapters of this

were re published in 1957. Note that F.G.W. Struve tended to publish

under W. Struve.

In these Struve's definitive conclusion was that the overall length of the

meridian arc was 1 447 787 toise (= 2 821 833 m) for 25º 20' 08.29".

However, Struve became ill and could not complete the compilation of

astronomical results and derivation of the definitive values of the earth’s


29 Nov. 15, 2012

parameters “a” and “f” (Figure 6 and Table 8). He only derived

preliminary values of these combining his results with those of Bessel

and Everest, resulting in semi-major axis (a) = 3 272 539 toises and

flattening (f) of 1:294.73.

He did however make other calculations with varied results. Others

since, including Bessel (from 1834 to 1841) and Clarke (1858 and

1861), and many others afterwards all used Struve's latitudes and arc

section lengths to combine with other arcs around the world.

j) Accuracy: Among the various figures Struve gave were those for a measure of the

accuracy achieved in the various sections were values for the probable

error of each of the 12 sections between successive astronomical

stations. This gave the following list and indicates the overall high

accuracy of around 1/200 000 (i.e. 5 mm per km) achieved.


30 Nov. 15, 2012

k) Summary: 1830: End of phase one, there was a complete meridian arc from

Gogland in the Gulf of Finland (latitude 60º 05') to Belin (latitude

52'02') = 8º 03' extent.

1844: End of phase two, there was a complete arc from Tornea to the

Dnestre river (latitude 48º 45’).

1851: End of phase three, there was a complete arc from Fuglenaes to

Staro-Nekrassowka except for the need to add some supplementary data

and re-observe various suspect stations- which took place during the last

phase.

A summary of the whole arc:

Northern terminal Hammerfest (Fuglenaes) latitude 70º 40'11.23" N

Southern terminal Ismail (Staro-Nekrassowka) 45 º20’02.94’’ N

Difference in geographic latitude 25º20’08.29’’

Difference in toises 1447786.783 ± 6.226

kms 2821.833711*

Origin of the meridian arc located in Dorpat latitude 58º 22' 47.56"±

0.05''

Time difference between Greenwich and Dorpat 1h 46m 53.536s ±

0.066s

Then longitude of Dorpat related to Greenwich = 26º 43' 23.04"

* Value in kms will vary slightly according to conversion factor used.


31 Nov. 15, 2012

The Struve chain brought

several benefits. The long and

accurate chain gave a fine

addition to the determination of

the spheroid but it also had

plenty of indirect influence.

The principles of the work were

published in all details and this

made the arc a good example

for others to adopt. Even the

personal contacts made over the

forty years were important. For

instance, Struve had an

influence on the measurement

of an arc along the line of

latitude 52º carried out in the

second half of the century. It

was Tenner who asked Bessel

to derive new dimensions of the

earth incorporating use of the

Russian arc.

Many chains were measured in

different continents in

subsequent years. Some results

of these activities can be seen

in the development of the

computed dimensions of the earth.

Very clearly the mutual agreement has become better since the

publishing of the Struve arc and succeeding measurements. This has

given a good start to uniform mapping, its framework and the map

projection systems.

Triangulation Chain from Arctic

Sea to Black Sea


32 Nov. 15, 2012

Toise values from Struve records:

Meter values by use of conversion factor K = 1.949 067

Note that Vassiljev in his paper of 1994 appears to have used K = 1.949

and hence all his meter values are less than those above.


33 Nov. 15, 2012

In all the toise-meter conversions the last three decimal places make

noticeable differences. These digits are found variously as 087, 081, 067

(0668) or 061. Foot values are from 34-35.

Indirectly it has also helped the spread of the metric system as it became

more generally accepted in principle at the international agreement in

the year 1875. It is true that the length of the basic unit no longer

depends on the determination of the earth dimensions but in the 19th

century it was the chosen way.

Because of the number of countries it passes through the Struve arc has

had a remarkable effect on the framework for mapping. Strong chains

with permanent marking and good documentation have ever since

belonged to the basic work in many countries. New base lines and

astronomical stations were distributed along the Struve arc triangulation

chain and made it an inseparable part of developing a traditional

framework for European geodesy and mapping. These principles have

then been followed for nearly 150 years until the Global Positioning

System (GPS) has now completely changed the methods.


34 Nov. 15, 2012

The Struve arc has not only served triangulations as an example. Its

points have been the starting points to many new triangulations and

traverses in the intervening period.

Up to the 1960s the Struve arc was the only connection of coordinates

between South and North Finland. An additional advantage has been the

careful trigonometric leveling along the points in the chain.

Data from this arc was used in 1942 by Izotov and Krassovsky in their

ellipsoid calculation and as recently as 1956 in the new determination of

the figure of the earth by Chovitz and Fische. Norwegian geodesists

repeated the astronomical observations at Fuglenaes in 1928 with Hans

Jelstrup and in 1950 with Yngvar Schiott. There was good agreement

with a variation in latitude of less than 6m.

l) Subsequent Comparison: The amount of work is not the only merit. Taking the instrument and

observation techniques of that time into account the achieved accuracy

was amazing. Co-ordinate transformations between some Struve points

and coinciding new points measured applying the best methods over one

century later, have revealed an unexpected quality.

The discrepancies were of the order of some centimeters, maybe one or

two decimeters. One lost Struve point was found when measured from a

nearby new triangulation point. It was about one decimeter from the

computed site. Perhaps the accuracy of the methods of the time deserves

admiration.

m) UNESCO World Heritage: In 2005, the Struve Arc was inscribed on the UNESCO World Heritage

List. This inscription is located in ten countries, the most of any

UNESCO World Heritage.

The Scientific Conference in Tartu took forward the idea and on August

28, 1993 agreed the following


35 Nov. 15, 2012

Resolution No 1:

“Considering the scientific, historical and practical importance of the

measurement of the arc of meridian through Tartu, made by F.G.W.

Struve, Urge the governments of those countries that still possess relics

of that enterprise to take all possible steps to preserve those relics,

including an approach to UNESCO to declare them to be World

Heritage sites.”

A corresponding resolution 1/2 1994 was then made at the FIG Congress

at Melbourne in 1994:

“Considering the great historical value of the measurement of the arc of

the meridian, and that an inventory exists of land monuments marking

the arc of the meridian, called Struve, which extends over 9 countries

and 25º of latitude from the Black Sea to Hammerfest situated on the

north coast of Norway, Commission 1 recommends that FIG should

present a request to the United Nations that the remains of this arc of

meridian be added to the World Heritage List of Historical

Monuments.”

A similar conference to that of 1993, held in Tallinn and Tartu from 25

to 28 September 2002 under the title “Struve Arc 150”, was an ideal

opportunity to discuss the arc in detail and to progress the efforts of the

International Institution for the History of Surveying & Measurement

(IIHSM) to have selected points in each country recognized by

UNESCO as a World Heritage Monument. 50 delegates from 10

countries attended- namely Norway, Sweden, Finland, Russia, Estonia,

Latvia, Lithuania, Belarus, Ukraine, Moldova, Belgium and UK.

Despite the setbacks a final document of 270 pages was produced in

time for presentation to the UNESCO in January 2004. The 18 month

period of scrutiny within UNESCO and ICOMOS (International Council

on Monuments and Sites) seemed endless but at last a decision was

made on 15 July 2005 at the UNESCO annual meeting in Durban, S

Africa. World Heritage status had been achieved. 34 points in Norway


36 Nov. 15, 2012

(4), Sweden (4), Finland (6), Russia (2), Estonia (3), Latvia (2),

Lithuania (3), Belarus (5), Moldova (1) and Ukraine (4), were registered.

1) Norway:-

1: Northing: (70°40'12'') Easting: (23°39'48'')




2) Sweden:-





3) Finland:-







4) Russia:-




37 Nov. 15, 2012

5) Estonia:-




6) Latvia:-



7) Lithuania:-




8) Belarus:-






9) Moldova:-


10) Ukraine:-




38 Nov. 15, 2012



Map of The Struve Geodetic Arc


39 Nov. 15, 2012

The Arc of 30th Meridian:

a) Introduction: Uganda, The Sudan and Egypt – which between them have more than

half of the 608 stations on the Arc of the 30th Meridian. Work on the

Arc here took place over a period of 50 years. The various parts of this

are summarized to illustrate to realize David Gill’s dream, who worked

in these countries in early 20th

century.

Four distinct periods are noted: 1908-1909, the 2º arc in Uganda; 1800-

1930 in Egypt; the Sudan before 1950 and 1952-1954 closing the gap in

the arc in Uganda and Sudan.

b) Background: At the beginning of the 20th century there were three colonial powers in

the central part of Africa, namely Belgium, Germany and Great Britain.

There was controversy between them as to the sphere of influence in this

region. "Artificial" boundaries had been established a long time before,

and due to the newly discovered parts, it often led to disputes.

In 1894, agreement was signed between Congo and Great Britain, which

met with the protest from Germany because some points in this

agreement were contrary to the earlier, 1890 British and German

convention. To settle the continual boundary disputes, the Anglo

German Boundary

Commission was formed in 1902. This Commission, through the

Colonial Office, bore the greater part of the cost of camp equipment and

tools with donations from professional societies.

The fixing of the true position of the 30th meridian between Uganda and

the Belgian Congo led to a controversy as to the boundary, and in 1906 a

Commission was sent to survey the territory in dispute. This joint

Anglo-Belgian Boundary Commission under Lt Col Bright was

operating in the region near the 30th meridian lying between Lake


40 Nov. 15, 2012

Albert and the parallel 1º S, and this appeared to both Gill and to Sir

Herbert Read (an original member of the Colonial Survey Committee),

to be a good opportunity to utilize some of the personnel of the joint

Commission to measure that part of the arc of meridian which traversed

the area in which the Commission had been working. This was agreed

by the two Governments; Belgium appointed M Dehalu an astronomer

from Liege University to assist.

c) Measurement: Four distinct periods are noted:

1: 1908-1909 (the 2º arc in Uganda)

2: 1800-1930 (in Egypt)

3: 1935-1950 (in Sudan)

4: 1952-1954 (closing the gap in the arc in Uganda and Sudan)

1) 1908-1909 (2º Arc In Uganda):

In August 1908 command of British party went to Capt. E M Jack who

was joined by G.T. McCaw as assistant observer. The party observed an

arc from 1º11' N to 1º11' S together with Belgians and a base was

selected at Semiliki (northern part of the Lake Albert flats).

Sixteen trigonometric stations were fixed and permanently marked. 35

triangles in five figures were observed with a 10-inch Repsold

theodolite, lent by the Transvaal Government using 5 inch helios and

acetylene lamps. Using Repsold theodolites and a zenith telescope M.

Dehalu observed over a period of nine months 14 latitudes using up to

49 distinct pairs of stars at a single station, and azimuths at Omunturok,

NKenda and Kikerere.

Climatic conditions were poor in the Ruwenzori Mountains, and each

station took an average of 36 days to complete.


41 Nov. 15, 2012

During the same period Dehalu and Wangermée took magnetic

declination observations at 58 main points of which 15 were geodetic

points. In the same reference is a comment:-

"The geodetic points are marked on the ground by piles of dry rocks, in

a conical shape, around 5m diameter at the base and about 2.50m high;

in the center, following the axis is fixed an iron tube 3m long

surmounted by two circular metal discs set at right angles to one

another."

The length of the Arc measured in Uganda was a little over 2º and

extended from the frontier of Uganda on the south to the southern shore

of Lake Albert, so that not all the meridional extent of Uganda was

traversed. Thus between Lake Albert and Aswan in Egypt there was a

big gap in 1929.

At a station at Kasunju (East of Lake Edward) small crater lakes are

visible. Not only would it have been practically impossible to occupy the

summit of Ruwenzori over 16 000 feet in height, but even on the higher

of the two spurs which had been occupied, on Karangora peak (Between

Lake Albert and Lake Edward) observations were secured with great

difficulty.

Observations for latitude were made at 14 out of the total of 16 stations,

and for azimuth at 3 stations.

At one of the latter points (Kkenda) the attraction from the west must be

very considerable, yet the effect on azimuth was very slight. In such a

greatly disturbed region it might be expected that the deviations of the

vertical would be marked, and they are. They rise to over 20 seconds. In

order to obtain a reasonably correct value of the latitude, the measures at

all stations north of the equator had to be rejected, and the latitude

finally selected as standard was derived as a mean of the seven stations

south of the equator.


42 Nov. 15, 2012

The attractions on both the western and eastern sides of the chain are

largely local and indeed, the greater deviations might have been

anticipated qualitatively, being conditioned by the central mass under

Margherita and the rift valley to the north, including Lake Albert. On the

western meridional line the geoid rises to the escarpment north of Lake

Victoria, on which stands Isura; on the eastern meridional line, on the

other hand, in the same latitudes, the geoid drops in the Lake Victoria.

On both the eastern and western lines the latitude of the summit of the

geoid is approximately 0º25' N.

The geoidal surface must vary considerably in an east-west direction; it

will be seen that in this sense also it rises towards Margherita and climbs

steeply from Lake Albert towards the Isura Escarpment.

The only baseline in Uganda, at Semliki, was observed August and

September 1908 by G T McCaw, Capt. Jack and Dr Chevallier and had a

reduced length of 16 532.37644 m. It was located in the Semliki valley

in Toro to the South of Lake Albert and was measured with 6 Jäderin

invar wires of 24m each standardized at Sèvres and the NPL.

2) 1800-1930 (In Egypt):

The project started in 1907 when Capt. H G Lyons became first

Director General of Survey in Egypt when it was founded in July 1898

and stayed until 1909. He began the geodetic triangulation of Egypt

along the NILE VALLEY in 1907.

The main triangulation of Egypt consists of a narrow belt of braced

quadrilaterals running north along the valley of the Nile from near the

frontier with the Anglo-Egyptian Sudan to Cairo.

The reconnaissance survey of somewhat less than 150 km was a long

strip from Cairo (lat. 30° N) to Beba (modern Biba) (lat. 29° N), carried

outby E Wande, under the charge of B Keeling, the superintendent of the

Helwan Observatory near Cairo. Two baselines were chosen at this time:


43 Nov. 15, 2012

one near the Helwan Observatory and the second one, called Beni

Suleiman (lat. 29° N), between Beba and Beni Suef.

It is reported that a second section joining Cairo to Suez has been

completely observed and computed. This is the first stage of a junction

of the Egyptian geodetic chain with the Palestine triangulation.

At the end of 1909, the reconnaissance was carried southwards to Assiut

(lat. 27° N), where the third baseline was selected. In the following years

as the work extended further south other baselines were measured at

Luxor (lat. 25°40' N) and Aswan (lat. 24° N). The angular observations

on the section, between these two latter baselines, and the determination

of astronomical latitudes, were carried out by J H Cole, and for the first

time since 1907, by an Egyptian, Ibrahim Azzam.

In the 1920s, a chain of triangulation was observed southwards along the

Nile Valley in Egypt as far as Luxor under the direction of Captain (later

Sir Harry) Lyons RE. This was soon extended to Aswan under the

direction of Hussein Sirry Bey and thence to Adindan (north of the

Sudan border, Aswan, Egypt), across the border from Wadi Halfa in the

Sudan. This triangulation followed the course of the Nile from Cairo

southwards.

The geodetic triangulation from Cairo to Aswan- some 550 miles- was

of a very high order. At the time of starting this work the latest available

figure of the earth was that by Helmert (a = 6 378 200 1/f = 298.3) of

1906, and the domestic geodesy of Egypt, including lower order

triangulation continued to be based on that figure.

This figure was used in preference to those of Clarke. When the Madrid

Conference of 1924 accepted the figure of Hayford 1910 it was too late

to change as the mapping was so far advanced although for scientific use

the triangulation was computed on both figures. The positions of the arc

have been recomputed on Hayford figure, but judging from the printed

report of 1927, the result may increase the A-G differences. The


44 Nov. 15, 2012

positions of all trignometric points were also given on the Transverse

Mercator.

When the geodetic triangulation started there was only one point of fixed

longitude in Egypt. This had been achieved at the time of the 1874

transit of Venus (connected, through subsidiary triangles, with The

Helwan Observatory) at Moqattam Hill near Cairo by the exchange of

telegraph signals with Greenwich Observatory and at the same time with

Suez (Northern Egypt) similarly determined by Sir David Gill in 1874.

For latitude, the mean discrepancy between the astronomical and

geodetic latitudes of the first eight stations south of Cairo was made

zero. The Egyptian chain, between Cairo and Adindan (north of the

Sudan border, Aswan, Egypt), was adjusted in blocks. Laplace azimuths

were used only for the southern section, between Aswan and Adindan. A

chain from Cairo to Suez was established with a view to a future

connection with the parallel Indian Arc.

3) 1935-1950 (In Sudan):

In 1893 Major M.G.Talbot went to Wadi Halfa (Southern Egypt) and

began a small triangulation after fixing his position by telegraphic

comparison with Cairo. Subsequently he went into the Nubian Desert

(North of Sudan) and determined the position of the oasis Murrat Wells

(Northern Sudan). During the winter of 1893-4 he commenced

triangulation from Suakin (west of Red Sea, Sudan), in 1896 completed

a triangulation survey from Halfa to Kerma (at bank of Nile in Sudan) ,

in 1898 he fixed Merowe telegraphically and began a small triangulation

between there and Abu Hamed. On January 1st 1900 Talbot was

appointed to the newly created post of Director of Surveys and then

resumed mapping the country.

Gwynn surveyed the Eritrean frontier from Kassala (Eastern border of

Sudan with Eritrea) to the Red Sea, closing on the Suakin (Cost of

Sudan in North of Eritrea) triangulation. He measured a base at Kassala

and began triangulating northwards in December 1901, completing it at


45 Nov. 15, 2012

Suakin in March 1902. In 1903 the Butter-Maud Expedition was to

survey the Kenya east of Lake Rudolph (now Lake Turkana) and to

carry triangulation to the north end of the lake in Ethiopia. They

measured a base of 3 ½ miles near Lake Rudolph.

Pearson succeeded Talbot as Director of Surveys, with Lieut. A.E.

Coningham as Assistant Director. During 1905 and 1906 Coningham

became proficient at triangulation covering 5000 sq. miles in one season

and in 1907 he started triangulation south from EI Obeid (South of

Northern Sudan).

In 1928 a detailed resolution was passed at the first Conference of

Empire Survey Officers and this led to the work by an imperial party in

Tanganyika Territory, who were to connect the existing parts of the Arc

in Northern Rhodesia (now Zimbabwe) and Uganda, from where the

chain was to be continued northward into the Sudan.

In 1929 discussions about the most economical way of dealing with the

Sudan gap made considerable headway. Better knowledge of the Sudd

region indicated the possibility of taking the triangulation across this

area on dry land with the help of portable steel towers. E. K. G.

Sweeting was able to confirm this and suggested a feasible route, east of

the Bahr ez Zeraf, linking up the hills north of Juba with the Nuba

Mountains.

World economic crisis delayed it further because Sudan was hit

severely. In 1933 the question was reopened by the International Union

of Geodesy and Geophysics. They were able to loan a Geodetic

Tavistock theodolite from Tanganyika and had the promise of base-

measuring apparatus as soon as it was free. The fact that a single

reconnaissance cum beacon building party was put in the field in

October, 1935, was largely due to the energetic efforts of S. L. Milligan.


46 Nov. 15, 2012

Egypt had completed its part of the Arc to the Sudan border in 1930 and,

as the gap south of the Sudan had not been closed by 1935; the obvious

decision was made to begin in the north.

The field party started from Wadi Halfa with few fixed ideas. A request

for the loan of the "Macca" base measuring apparatus from the

Department of Lands and Mines of Tanganyika met with a favorable

reply in December, 1935. It was used on the Amentego (central North

Sudan) baseline. Work lasted from March 18th to May 1st, 1936, a total

of 45 days. The Quleit base was 6.2 miles long in latitude 13º 50' N. in

the Northern Kordofan (North Sudan). The distance from Amentego is

600 km. measured along the meridian line of the chain. Every effort was

made during reconnaissance to get its direction as nearly at right angles

as possible to the prevailing winter winds from the north.

The chain would follow the valley from Amentego southwards as far as

Debba (central North Sudan). The natural route for triangulation was

astride (on both sides) the river. But the only two places at which any

facilities at all existed for ferrying the cars across the river on east side

were Wadi Halfa and Dongola, and those at Dongola were very

primitive. A third ferry was later organized at El Ghaba (South Sudan)

just north of Debba.

Due to the Second World War, there was a delay and the work resumed

in 1947. Then, most of the pillars for the third section of the Arc were

built. The observations at the 25 stations of this section were carried out

during the observing seasons, until April 1952. D. T. F. Munsey was in

charge of the field party in the first seasons of 1949 and 1950. The

average triangular misclosure of the chain was 0.60". The Abu Qarn

(Southmost of North Sudan) base site was selected in 1951-52 by

Munsey and Mason at the southern end of the chain (lat. 10° N).

Mason started its measurement from Abu Qarn base and that of the

expansion figure in November 1951 and completed it in January 1952.

Unfortunately it was to be the most inaccessible of the entire base lines

in Sudan. From clearing the line to its completion took 39 days. The


47 Nov. 15, 2012

difference in length between the outward and reverse readings for all the

336 x 100 ft. bays was but 0.002 ft. For this section of about 4º the

closure on the Abu Qarn base from a triangle near Quleit was:

1:150 000 in length and 2 seconds in azimuth

The Sudan portion of the Arc was computed on the Modified 1880

Clarke ellipsoid. It was the recommendation of the Colonial Survey

Committee to have all African surveys based on the same ellipsoid. One

of the Adindan (Egypt) base terminals was chosen as the origin of the

Sudan part of the Arc. Its geographical co-ordinates were computed on

the Hayford 1910 figure of the earth. The longitudes required a

correction of +3.45".

4) 1952-1954 (Closing The Gap In The Arc In Uganda

And Sudan):

With the completion in 1940, of that part of the 30th Arc between Wadi

Halfa and El Obeid in the Sudan, there remained only a gap of some 630

miles (1000 km) to make the Arc complete from near Port Elizabeth

(South Africa) northwards to Cairo. Half of this 630 mile (1000 km) gap

was probably the most difficult section of the whole Arc from the

surveying point of view, involving as it did the crossing of the vast Sudd

area of the Southern Sudan.

This gap extended from the Semliki flats, at the southern end of Lake

Albert (now Lake Mobutu Sese Seko) in Uganda and the Belgian

Congo, to the Nuba Mountains in Sudan.

There was a distance of about 315 miles (500 km) crossing the Sudd

region in Sudan, with no hills and floods occurred there during the rainy

season.

From Juba to Abu Qarn along the Nile valley the chain crossed such flat

country that 33 m towers were required throughout. This section of the

Arc was carried out mainly in the interest of the international geodesy.


48 Nov. 15, 2012

With the possibility of the “Cold War” the United States Government

decided that a more accurate figure of the earth was essential for the

calculation required for long range rocket warfare and decided to

measure most difficult gap extended from the Semliki flats to the Nuba

Mountains in Sudan.

At the Conference of Commonwealth Survey Officers in 1951

discussions led to a request that a resolution be passed to encourage the

execution of the necessary work.

The American observer, Mr Floyd Hough, indicated that he would be

making a proposal on these lines to his superiors and Conference duly

passed the resolution proposed by Martin Hotine and seconded by

Colonel Baumann of South Africa. Soon afterwards, a proposal by the

United States Army Map Service, which had available the required

equipment and the necessary skilled personnel, either of their own, or on

secondment from the Coast and Geodetic Survey, for the completion of

the work was submitted to the governments of the Sudan, Uganda and

the Belgian Congo. This was quickly accepted and, by mid-December

1952, a large United States team was in position in Juba in the southern

Sudan.

The party formed up in the Sudan in 1952 and by their first entry into

Uganda in April 1953, had observed a large part of the chain across the

extremely difficult Sudd region using Bilby towers as “stepping stones”

and bulldozing some of the taller parts of the scrub, to get as long lines

as feasible. Even then, assuming level ground between them, the stations

could only be sited a maximum of 18 miles apart. With 18 mile

diagonals on braced quadrilaterals, this meant that side lengths could

only be some 12 miles long at their maximum if forward movement was

to be maintained without expense to figural strength.

The party from the AMS (American Mathemitics Society) cooperated

with the survey departments of the other countries. All operations in

Sudan were carefully planned with the assistance of the Director of the


49 Nov. 15, 2012

Sudan Survey Department, Mr. Wakefield. Due to the short, four months

dry season in Sudan, it was decided to complete the triangulation work

during two seasons. The operations started in December 1952 from Juba

(the Luluba base) and proceeded northwards to the Ayod (South Sudan)

base.

The steel towers were of the Bilby type and consisted of inner and outer

towers of heights between 50 and 103 feet. Sudan provided twelve

towers and five were brought from America.

Among the array of equipment was a De Havilland “Beaver”, seating

four passengers, plus pilot and mechanic; it could be used to drop mail,

messages and spare parts to the observing teams. This type of plane was

able to take off from a short runway carrying a heavy payload and was

very popular for survey work in Canada, their country of origin.

Due to bad climate Ayod baseline was measured at the end and then the

work was started from the Semliki base in south between Congo and

Uganda. The Semliki base had been measured in 1908, when another

section of 150 miles of the 30th

Arc was surveyed southwards along the

eastern side of the Ruwenzori, and down into Tanganyika (then German

East Africa). With a probable error of better than 1 in a million, the base

was regarded as being sufficiently accurate for carrying the Arc

northwards for some 300 miles (480 km) to the new Luluba base near

Juba in the Sudan.

The Semliki base had not been visited since the early 1930s, but

reasonably adequate description cards were obtained from the Entebbe

office, and both Kibuku (Eastren Uganda, border with Kenya) and

Makoga (Westren, Uganda border with Congo) were easily found with

the old beacons (steel pipes with round petrol drum tops as signals) still

standing, but with considerable slant. Isura and Omunturok, the two

western expansion stations, were both in the Congo.

Before any observing commenced the Arc stations were reconnoitered

right up to the line Zeu (302) – Erusi (303), on the Uganda –Congo


50 Nov. 15, 2012

border, to the north-west of Lake Albert. Proposed stations from existing

map of the area for 110 miles of Arc were positively identified, inter-

visibility checked, and best methods and routes of ground approach

studied, in four hours flying from Fort Portal ( west of Uganda), by the

observer who would later be occupying the particular station. For

checking inter-visibility, this was done by plane.

When there was any doubt about a line being clear closer flying was

employed. In these cases, the line Zeu-Erusi (north west of Lake Albert)

was one, for example, the pilot having flown along the bearing to the

new station, and identified its proposed position, would then go a mile or

two further with one of the passengers keeping the hill in view, and then

turn the plane round sharply and fly back along the back bearing. As he

approached the hill, with the plane on bearing, he would cut airspeed to

its minimum and come down low over the ground, and then fly up the

side of the hill, and as the plane flew a few feet over the top, the

observers would crane forward to see if they could see the back station

ahead on line- if so, well and good- but if not the pilot would repeat the

process and sometimes even go back and try the line again from the

other end, until the chief observer was sure that a satisfactory ray would,

or would not, go through.

Observing parties were all equipped with Wild T3 theodolites which had

been found to be robust, accurate and yet comparatively light in weight,

and all the observers were at home with them, as also with the Parkhurst

theodolites that were the standard geodetic instruments in the United

States at that time. All observations on the Arc were done at night to

signal lamps, following USC&GS practice.

Sixteen rounds of horizontal directions were laid down for geodetic

triangulation, and these were observed on both faces. The rejection

limits for a single observation was 4 ″ from the mean. Extra rounds were

taken until a full set of 16 rounds was obtained with a spread of less than

8″.


51 Nov. 15, 2012

On July 8th 1953 the next 50

miles of Arc up to the latitude

of Arua were reconnoitered by

the plane from the Arua

airstrip, and one alteration to

the preliminary diagram was

found desirable. By the end of

July, observations had been

completed up to and including

the line Oyii-Kuching (north of

Lake Albert).

The remaining Uganda lines up

to the Sudan border were flown

on August 3rd and marking of

these stations then went ahead

whilst the observers were

moving up two figures behind.

By the end of August all the

stations in Uganda had been

completed, including a

triangular fix to Koboko

(north of Uganda) for the Ugandan Survey Department so that it could

tie on a few local surveys in that area.

For the entire Arc between the Semliki and Luluba bases:-

1. Distance: 263 miles

2. Triangles Closed: 84

3. Max Triangle Misclosure: 1.81″

4. Average Triangle Misclosure: 0.52″

In October, the party reached Juba in Sudan. When roads were declared

open in December 1953, the party moved to the Ayod base to restart the

work here which was aborted due to bad climate to tie the existing

triangulation in the Nuba Mountains. Now towers were erected at the

The 30th Meridian Arc


52 Nov. 15, 2012

rate of one a day and progress was rapid. The gap in the Arc, between

the Semliki base and the Abu Qarn base, was closed on the night of 27

January 1954. Sir David Gill’s arc from the Cape was connected to

Cairo.

Overall, 109 stations (63 on towers), with 253 triangles had been

observed in 13 months. Astronomical azimuths were observed at six

stations. The maximum triangular closure was 2.11” with an average

value of 0.58”.

d) Summary: The 30

th Meridian Arc was started in 1879 by David Gill and by 1892 all

of its length in South Africa was complete together with two of the four

baselines. 1897-1901 saw much of Southern Rhodesia (Zimbabwe)

completed by Simms except for a small piece around 21º-22º south

which was filled in later. 1903-06 saw Rubin complete most of Northern

Rhodesia (Zambia) and in 1908-09 Jack and McCaw did a section in

southern Uganda. Thus between 1879 and 1909 the great majority of the

triangulation from S Africa to the Equator was completed. The gap was

from 10º S northwards to 1º S. This was partly completed by Hotine in

1931-33 and the rest by the Tanganyika (Tanzania) Survey Department

in 1936-38.

Looking now from the Mediterranean Sea southwards Egypt was

covered between 1907 and 1930 and much of The Sudan at varying

periods between 1901 and 1951. This left one last section of around 600

miles in southern Sudan and Northern Uganda which was the most

difficult of all because of the terrain in the Sudan. This was finally filled

in with the assistance of the US AMS during 1952-54. So the whole arc

had taken 75 years to complete.


53 Nov. 15, 2012

Possibilities Of Being The Only Arc Measured From The Arctic Sea To The Antarctic Ocean: Further extensions in the 20th century have resulted in the "Struve" arc

now theoretically reaching from near North Cape in Norway to Port

Elizabeth in S. Africa.

It was 1954 when two quite separate arcs- that by Struve and that started

by Sir David Gill around 1882 in South Africa which gradually worked

its way northwards, made a link-up feasible.

Before discussing the future possibilities, a light background needs to be

disclosed here.

a) Background: In the Introduction to his volumes Struve wrote (translation from

the French):

“The arc between the mouths of the Danube and the Arctic

Ocean can at this stage be regarded as the major part of an as

yet unfinished task. In effect nature places no obstacle to the

continuation of our triangles by an arc of nearly 12 degrees in a

southerly direction towards the island of Crete, crossing

continental Turkey and the islands of that Archipelago. Between

Fuglenaes and Crete there are more than 37 degrees of latitude,

which constitutes the European Meridian of the greatest

possible extent, and at the same time this arc is the closest to the

mean meridian of the continent of Europe which extends, west to

east, from Cape Finisterre, longitude 8º 20’ from Ferro to the

town of Iekaterinbourg, longitude 78º 14’. The mean is at 43º

17’; Dorpat lies at 44º 23’.”


54 Nov. 15, 2012

1) Reconnaissance Of Otto Struve:

In 1868 Otto Struve (son of F G W Struve) published a detailed paper

(Struve, 1868) on reconnaissance that had been done under his

supervision. This extended from the first baseline north of Izmail - that

at Tachbounar- through present-day Romania and Bulgaria to Greece,

Turkey and the Greek Islands near Crete.

This ran generally about 100 km west of the coast of the Black Sea

before crossing into Turkey near Edirne and continuing south to near

Gallipoli and then Izmir to Kos and the possibility of sighting to Crete.

Crete was the most obvious end point. But the further work was to have

been with the co-operation of Turkey but somehow or other almost at

that precise moment conflict arose between the two nations and it would

appear that the field work never took place.

It was around the same time that David Gill was taking over as Her

Majesty’s Astronomer at the Cape (of Good Hope). Now he had

corresponded for some while with Otto Struve and they both had the

same dream of someday connecting the two Capes (North Cape in

Norway with Cape Province) with a triangulation scheme. While Otto

Struve was striving to extend his father’s work to Crete so David Gill

was planning a Cape to Cairo triangulation. Such schemes would have

left but the crossing of the Mediterranean Sea as a gap in the Cape to

Cape dream.

2) Work Of David Gill And American Air Force (North

Africa To Crete):

Gill started work in South Africa on a geodetic The 30th

Meridian Arc in

1879. It was not completed until 1954. The same year a crossing of the

Mediterranean Sea from North Africa to Crete using Hiran/Shoran was

executed by the American Air Force.


55 Nov. 15, 2012

3) Crossing The Mediterranean Sea:

By the time of completion of the 30th Arc survey techniques had

sufficiently developed for it to be no longer necessary to carry the

connecting survey round the Eastern end of the Mediterranean Sea

through Palestine, Syria and Turkey before striking out northwards

towards the Struve Arc. Using Shoran/Hiran, a form of radar technique

to accurately measure very long distances, a connection was feasible

from the North African coast to Crete. To do this the Arc in Egypt was

extended westwards to just inside Libya so as to set up three survey

stations that would make a suitably shaped figure with three points on

Crete and Rhodes.

Thus was completed the whole of the section from near Port Elizabeth in

S Africa to Crete and on northwards to the North of Norway although

many of the records for the connection south from Poland remain to be

found.

“Shoran (Hiran = high accuracy Shoran) was an airborne navigation

system capable of determining long distances (several hundred km) to

accuracies of interest to the geodesist. It was essentially a trilateration

technique.”

4) The Connection From Poland To Crete:

Between the two Great Wars there were moves in the IAG (International

Association of Geodesy) to observe an arc of Meridian from the Arctic

Ocean to the Mediterranean Sea.

Maps of this new triangulation indicate that there were up to 14 survey

stations said to be “coincident with Struve stations”. The difficulty with

this connection is that when it was observed the territory was part of

Poland, today it is in Belarus. Neither country seems to be sure which

holds the records (if any still exist) of the survey observations and

results or in fact whether they might even be held somewhere in Russia.


56 Nov. 15, 2012

Several of the possible coincident

stations have been investigated and it

was reported in 2004 that the Polish

chain coincided in three areas with

that of Struve. However not all of the

stations described were truly

“coincident” but other stations of the

same name nearby. Some 7 stations

can be either proved or look

promising if coincidence can be

verified.

The map in below shows the

triangulation from Poland

southwards. The location of the

coincident points between this

triangulation and the Struve Geodetic

Arc is further north in Poland just

south of its border with Lithuania. It

is hoped that these stations will be

further investigated in the near future

so that there is a firm foundation on

which to pursue the rest of this

triangulation down to Crete. Africa

mostly by the British over many years

used to be all kept in one archive but they have recently been dispersed

to seven different locations to make it infinitely more difficult for

researchers.

Poland Triangulation to Crete


57 Nov. 15, 2012

b) One And The Only Arc Measured From Arctic Sea To The Antarctic Ocean: At present all the work is complete from Cape to Cairo, Cairo to Crete

and from Arctic Sea to Crete. There is just a need of its international

recognition. Efforts are being done to achieve the UNESCO World

Heritage status for the remaining arcs. So that the work can be restored,

published and preserved. And re-establishment of the lost control is

severely needed. It will lead the arc towards completion.

The other possible arc can be one having route from north pole through

Greenland, crossing Canada and USA, Mexico, Guatemala, Honduras,

Nicaragua, Costa Rica and Panama. After this it would be entering into

South America.

After this it would be crossing Colombia, Brazil, Bolivia and Argentina.

The south of Argentina is nearest to the South Pole.


58 Nov. 15, 2012

Although the hurdle of the Antarctic Ocean between Argentina and

Antarctica is minimum, but no or less work on that route has been done

in the way of this route. The climatic condition of Greenland is very

severe. Some other factors like difficult terrain and less availability of

any previous work are also involved in the less possibility of this arc to

be measured.

This makes clear that the possibility of The Struve Arc is maximum

(after its connection with The 30th

Meridian Arc) of being one and the

only one arc measured from The Arctic Sea to The Antarctic Ocean.


59 Nov. 15, 2012

APPENDIX A few words about the principal individuals involved are appropriate

here.

a) Tenner: Carl F de Tenner, or in the Russian

manner, Karl Ivanovitsch de Tenner was

born 22 June 1783 near Narva and died 28

December 1859 in Warschau. He spent

much of his working life on the arc

measurement.

He became a professional surveyor by,

presumably self-education, as did Struve

and Bessel. As a General of Infantry of the

Russian Imperial General Staff, he

participated in many war campaigns

against Napoleon’s troops, where his

courage was rewarded with a golden

sword and other Orders. In 1816 he

was appointed head of the vast

Russian triangulation work in western provinces of the Empire where he

spent much of his working life. It was he who started measurement of a

meridian arc (in 1817 south of Livonia) just on his own initiative,

without any funds. He was in charge for a portion of 11º 10 ′ between

the Danube and the Duna (Dvina), or from 45º20′ and 56º30′ N, and

which contained 5 baselines and 125 main triangles. He became Struve's

friend, and had contact with F Bessel and other prominent scientists. He

was an honorary member of the Russian Academy of Sciences.

Carl F de Tenner


60 Nov. 15, 2012

b) Hansteen: Christopher Hansteen was

born 26 September 1784 in

Christiana (now Oslo) and

died in the same city 15 April

1873. He studied law at

Copenhagen and later became

Professor at Christiana,

Director of the Christiana

Observatory and Director of

the Royal Norwegian

Geographic Department. By

1817 as a President of the

Geodetic Institute he played a

leading role in the survey of

Norway. He was particularly

interested in geomagnetism

and magnetic charting. For his

part he was in charge of 1°46’

of the arc between Atjik and

Fuglenaes on the isle of Kval-

oe, in the Arctic Ocean, or from

68°54’ to 70° 40’ with one baseline

and 12 main triangles.

c) Lindhagen: Daniel Georg Lindhagen was born on

27 July 1819 in Askeby near

Linköping, Sweden and died 5 May

1906. He was a Swedish astronomer

who worked in Pulkovo before

returning to Sweden to work a few

years after his marriage. He spent two

Christopher Hansteen

Daniel Georg Lindhagen


61 Nov. 15, 2012

summers on survey work in Lapland. At that time Struve was over 50

years old and headed the Observatory in Pulkovo so he delegated the

astronomical work to Lindhagen. Later he became permanent secretary

to the Royal Academy of Sciences in Stockholm. He married Wilhelm

Struve's daughter Olga.

d) Maupertuis: Pierre-Louis Moreau de Maupertuis was born

28th September 1698 in St Malo and died on

27th July 1759 in Basel. On 8 October 1745 he

married Eleonore Catherine von Borck. He

was said to have been a spoilt child and this

resulted in a certain intransigence and

unwillingness to be criticised that later led him

into difficulties. His early education was

private. His father was ennobled by Louis XIV

as Ren, Moreau

Sier de Maupertuys. After studying in Paris he

was in the French army until 1723 when he

became involved in the French Academy of

Sciences.

By 1728 he strongly believed in Newton’s idea on the shape of the earth

and began to work on his own theories and even published a treatise on

the figure of the earth which signaled the beginning of the establishment

of the Newtonian hypothesis in France. In 1736 he led an expedition to

Lapland to make a measure of a meridian arc and he was later involved

in further arc measurements in France. In 1745 he accepted an invitation

from Frederick the Great to go to the Academy of Sciences in Berlin

where he became its President.

Pierre-Louis Moreau de Maupertuis


62 Nov. 15, 2012

e) Selander: Nils Haqvin Selander was born on 20

March 1804 in Vibyggera

Angermanland, Sweden and died 18 June

1870 in Stockholm. He was an

astronomer and geodesist who became

Director of the Royal Swedish

Observatory. In 1833 he was elected a

member of the Stockholm Academy of

Sciences and began assisting at

Observatory in Stockholm.

From 1850 to 1869 he was Professor of

Geodesy at the Topographic Corps which

was responsible for topographical

mapping of Sweden and of its geodetic

systems.

Struve visited Sweden in 1844 and

contacted the Swedish Academy of

Sciences. The initial idea was to follow the Svanberg Arc and

incorporate it. However a Report by Selander and Wrede indicated that

the best solution was to complete the Struve arc over the longest

possible distance. They had planned the Arc as a separate Swedish work

from Tornea to Kautokeino where there would be a connection to

Norway.

Although initially they intending to do their own computations; the work

was finally done in Pulkovo in 1855. He was in charge of the 3º 13 ′ of

the arc between Tornea and Bäljatz-vaara in Norwegian Finnmark, or

between 65º 50 ′ to 69º 03 ′ and with one baseline and 21 main triangles.

He was one of the four persons who signed the report Karl Tenner,

Hansteen, Selander and Struve.

Nils Haqvin Selander


63 Nov. 15, 2012

e) Svanberg: Jons Svanberg was born 6 July 1771

in Neder-Kalix, Norrbotten, Sweden,

and died 15 January 1851 in

Uppsala. By 1787 he was studying at

Uppsala University where he was to

later become Professor of

Mathematics.

During the period 1799-1801 he led

a team that re-observed the work of

Maupertuis 60 years earlier at the

north end of the Gulf of Bothnia. In

doing so he extended the original

scheme. He had a love of decimals

(which is evident in the exaggerated

accuracy he quoted in his

observations) and complicated

calculations.

Bibliography:-

1. How F.G.W. Struve started his ambitious project? Tõnu Viik Tartu Observatory, Tartumaa 61602, ESTONIA Tartu University, Ülikooli str. 18, 50090, ESTONIA

2. Struve Geodetic Arc No. 1187

28 January, 2004

Jons Svanberg


64 Nov. 15, 2012

3. Workshop – History of Surveying and Measurement

WSHS1 – History of Surveying and Measurement

James Smith

WSHS1.3 The Struve Geodetic Arc and Its Possible

Connections to the Arc of the 30th Meridian in

AfricaFIG Working Week 2004

Athens, Greece, May 22-27, 2004

4. WSHS 3 – Arc of the 30th Meridian

J (Jim) R Smith

WSHS3.1 The Arc of the 30th Meridian North of the

Equator

From Pharaohs to Geoinformatics

FIG Working Week 2005 and GSDI-8

Cairo, Egypt April 16-21, 2005

5. THE STRUVE GEODETIC ARC

J R Smith

International Institution for History of Surveying &

Measurement (A body wholly within FIG)

September 2005

6. THE CONNECTION BETWEEN THE STRUVE

GEODETIC ARC AND THE ARC OF THE 30th

MERIDIAN

J R Smith

International Institution for History of Surveying &

Measurement (FIG)

September 2005


65 Nov. 15, 2012

7. HS 4 - Session 4

Vitali Kaptüg

On Comparison of the Three Meridian Arcs in Lapland

Integrating the Generations

FIG Working Week

Stockholm, Sweden 14–19 June 2008

XLt. Col. (R) Nasrul Haq

Instrutor For Surveying-II

the struve geodetic arc & its future possibilities of being the one

Engineering