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Menooa Badalian

mbadalia@usc.edu

The Original Transatlantic Communication

Abstract:

The Transatlantic cable, running under the Atlantic Ocean, is the groundbreaking

achievement of the late 19th

century. Since it was the first technology of its kind, engineers were

faced by impending decisions regarding the required material, sending signals efficiently, and

physically laying the cable across the Atlantic Ocean. Some of the problems they faced along the

way led to the development of some of the most notable concepts in physics and

electromagnetics. Since 1866, it has paved the way for future scientists and engineers to

constantly improve on the technology and create newer ones. The most notable advancements

that have been conceived from the Transatlantic Cable are the transatlantic telephone cable and

later on radio communication.

Keywords: Transatlantic Cable, Atlantic Ocean, communication, telegraph, Field

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Figure 1: The British Lion and the American Eagle connecting both continents by the Transatlantic Telegraph wire [2].

Introduction:

One hundred fifty years ago, the first telegraphic message was sent across the Atlantic

from Queen Victoria to President James Buchanan congratulating him on the success of the

transatlantic cable. This was officially the first telegraph exchange over the new cable, and it was

one of the greatest engineering achievements of the 19th

century, enabling Europe to be directly

connected to the North Americas [1]. A message that would have taken twelve days to travel

from Europe to the North Americas was being sent in matter of minutes; enabling people to share

news and common knowledge with each other across the two continents [2]. This article will

discuss the history of the Transatlantic Cable; how the idea came about, the problems faced by

the engineers and the solutions for these problems. Furthermore, it will also examine how this

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groundbreaking technology paved the way for the future generations to discover and create new

modes of communication.

History:

In 1937, C. Wheatstone and W. F. Cooke patents a workable telegraph [3]. In 1842,

Samuel F. B. Morse, the co-inventor of the Morse code and a well-known painter, experiments

with telegraph cable and sends the first message through a wire, enabling long distance

communication between two sources. In the same year, the United States Congress approves a

thirty thousand dollar bill to be used in construction of the first telegraph line across the United

States [4]. Two years later, in 1844, Morse builds the first North American telegraph system

between Washington, DC and Baltimore, Maryland [1]. By the next decade, the era of instant

communication was born; not only the United States but also most countries in Europe were able

to communicate with each other through wires. This allowed new sources of commerce to

develop and people were able to share common local knowledge throughout the United States

and Europe. Although, people in the Americas and people in Europe were able to communicate

with each other locally, oceans isolated the Americas from the rest of the world and international

news was still carried by wind and sail. It was still a dream for both Europeans and Americans to

be able to instantly communicate [4].

It was not until 15 years later, in 1857, when a young American businessman by the name

of Cyrus West Field got together with local investors and convinced them to invest in a project

that would attempt to link Europe and America through a wire. Even though in the mid-19th

century electricity was still a mystery and there was no adequate vocabulary to talk about

electricity, the investors agreed and invested large sums of money into the project. Cyrus West

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Field became the leading promoter of the great Transatlantic Telegraph Cable project and the

idea went into development [1, 4].

Cyrus Field and the Atlantic Telegraph Company decided that the best route for the cable

was from Telegraph Field, Foilhommerum Bay, Valentia Island in western Ireland to Heart's

Content in eastern Newfoundland. Once in place, locally connected cables on both sides of the

Atlantic would then distribute the signal within various cities inside the United States and Europe

[3].

Figure 2: The map of the submarine Atlantic Telegraph [8].

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Manufacturing:

The project required the right kind of wires, and overall wires are nothing more than a

conductor and an insulator. Even for a colossal wire such as the Transatlantic Cable, all that was

required was a conductor and an insulator. The challenge was to figure out a technique to

construct it in such a way that it would be strong enough to support different forces, flexible

enough to be coiled on board, and most importantly be salt-water proof [1].

Since the invention of the telegraph in the 1820’s, copper had been, and still is, the most

conductive non-precious metal, with a conductivity σ=5.96x107 Siemens per meter, known to

mankind [5]. With a distance of 2300 miles to travel, a heavy-duty conductor such as copper was

required to ensure that the signals traveled efficiently. An astounding 107 pounds of copper was

used for each mile of cable, totaling 246,100 pounds of copper for the 2300 mile cable [1]. With

the conductor in place, the next obstacle was to create the optimal insulation. At the time, gutta-

percha, “a rubber-like substance extracted from the sap of the gutta-percha tree”, had proven to

be a great insulator [6]. This substance, when heated to 150°C, could be easily molded into any

shape desired [7]. Once cooled, it was very flexible and strong. Above all, unlike rubber, instead

of deteriorating in sea-water, gutta-percha thrived in it [8]. It is interesting to note that this great

material is virtually unknown today and is used mainly in the field of dentistry to backfill

cavities [8].

Traveling Signals:

In order to insure that the signal would travel the great distance successfully, engineers

had to determine how much time was needed to recharge the capacitor that released charge into

the cable for every telegraphic pulse. For this, engineers relied on Lord Kelvin’s distance squared

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Eq1: Distance squared law: t = rcL2

Eq2: Ohm’s law: v=ir r = v/i

Eq3: Capacitance law: c =Q/v

where t = time for recharging capacitor

r = resistance

c = capacitance

L= length

v = voltage

i = current

Q = Charge

To make the substitutions with Eq1 and Eq2:

t = (v/i)cL2

To substitute further with Eq3:

t = (v/i)(Q/v)L2

When we simplify (cancel v’s):

t = (Q/i)L2

The final equation we obtain is therefore a version of Kelvin’s Distance Squared Law

in terms of charge (Q) and current (i).

In this equation, length (L), which is the length of the cable itself, and charge (Q) are

always constants. Therefore the only variable that can potentially effect the time for

recharging capacitor is current (i). We can see based on the equation that if we

increase current (i), time for recharging capacitor (t) will decrease; meaning that

signal will reach its destination at a shorter time because capacitor will need less time

to recharge and will be ready to release the charge.

Next, we need to look at how exactly we can increase current. For this, we look at

Ohm’s Law (Eq2) v=ir i=v/r. Here, resistance (r) will always be a constant.

Therefore in order to increase current (i) we must increase voltage (v).

The final result obtained is: In order to recharge the capacitor faster, voltage needs to

be high. The higher the voltage, the faster the capacitor will recharge and the faster

the signals will be able to travel across the cable.

law for cable transmission. The law states that the time needed for the recharging of the capacitor

is proportional to Resistance x Capacitance per unit length squared [1]. To put this into better

perspective, we can apply Ohm’s law and capacitance law to the equation as follows:

Equation 1: Lord Kelvin’s distance squared law and Ohm’s law [1].

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During the initial development phase, it was estimated that 500 volts of electricity would

be sufficient to transmit the signal across the Atlantic. However after more experimentation, it

was concluded that a voltage of 60 would be adequate [8]. To provide the necessary power,

engineers relied on a series of batteries. This included stacks of lead and acid cells as well as

more complex plate and electrolyte combinations known as the voltaic pile [8]. As a side note, an

electrolyte is any chemical compound that ionizes when dissolved to produce an electrically

conductive medium [9]. This combination, created about 50 years prior by Alessandro Volta,

was comprised of stacks of alternating copper and zinc disks. These disks were separated by a

layer of electrolyte made up of saltwater [10].

Transatlantic Journey:

With such a colossal cable, a powerful and equally colossal ship would be required to

transport it. With the technology of the late 1800’s, there was no such ship that could carry the

2300 mile cable in its entirety. What the engineers decided would be the best solution was to

split the cable in half. The United States and Britain would each construct half of the cable. Ships

from both ends of the Atlantic would carry each half to be connected at the midpoint of the route

[3]. The idea was feasible enough, however, engineers needed to ensure that the cable would be

connected uniformly, without any seams, to prevent breakage if it came in contact with a strong

enough force. This became possible due to the unique clay-like properties of gutta-percha. With

a melting point of 150°C, it was easy enough to melt the substance, shape it around the seam,

and mold it to create a continuous layer of insulation [8].

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Problems?

With such a well thought out plan, why is it that the first attempt for transatlantic

communication failed miserably on September 18, 1858? The answer is very simple; there

wasn’t enough knowledge of electricity at the time. Knowledge of electricity or “electronics”, as

it was known at the time, was very limited in the late 1800’s. This combined with the fact that

the chief technical advisor for the transatlantic cable, Edward Orange Wildman Whitehouse, was

only a physician who possessed the knowledge on electricity by teaching himself through the

years, led to the failure of the first attempt in transatlantic communication [2, 6].

The first problem arose when it took 11 days for a message to travel through the cable to

the United States. As a solution, Whitehouse increased the number of batteries used to operate

the cable, hence increasing the voltage to 2000 volts [8]. He believed that with such a long

distance to travel, the signal needed a jump-start in order to travel faster and more efficiently.

Based on the simple derivation of the time to charge capacitor equation provided above in

equation 1, we can see how he came to that conclusion; the higher the voltage, the faster the

capacitor would charge and could send a signal across the wire. Looking at this

in hindsight, anyone with basic knowledge of Ohm’s law can quickly

understand why this solution did not work.

According to Ohm’s law, voltage = Current x Resistance. Due to a

constant number of copper strands, the resistance of the cable was constant and

was approximately 3 Ohm/nautical mile [1]. As he increased the voltage,

current traveling though the cable increased as well. An increase in current

Figure 3: Ohm’s law

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meant that more electrons were passing though the cable at any given time. The increased

number of electrons generated more energy which was converted to heat and eventually

“melted” the cable from the inside.

Second Round of Celebrations:

In the next few years, the British government set up

an official panel to investigate the reasons behind the

failure of the cable. On April 1861, the panel published a

report that clearly blamed the manufacturing in the copper

core and insulation for the failure of the project [1]. The

panel also blamed Dr. Wildman Whitehouse, for having

tried to speed up the transmission by an increase in the

voltage as the cable worsened. After some research and

field trials, the committee released a report in 1863, which recommended feasible improvements

in manufacture, handling, and design of the cable. This meant an increase in the copper wires

that would withstand the voltage

passing through it. Where originally

the weight of the copper conductor

was 107 pounds per mile of wire, it

was now up to 300 pounds per mile

[1]. The end result, a 2300 mile cable

consisting of seven strands of copper

and four layers of gutta-percha

Figure 5: Shallow and deep water versions of 1865 Cable [1].

Figure 4: The Great Eastern [1].

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weighing 5000 tons [1, 8].

This new cable was both heavier and bulkier. Also, transporting it via two ships was not

viable anymore due to the increase in size. To solve this problem, a new ship, which was five to

six times the size of any other ship built, was bought. The Great Eastern, as the ship was called,

was capable of transporting 4000 passengers around the world without refueling [1]. Since

operating it was really costly, even with tickets purchased by 4000 passengers, the company was

going bankrupt; which meant that the Atlantic Telegraph Cable Company was able to purchase it

for two percent of what it had cost to build it [4].

With everything in order, 20 miles a day, 2300 miles of cable weighting 5000 tones were

loaded in three tanks abroad the Great Eastern [1]. Additionally, while transporting the cable to

the other end of the Atlantic, telegraphic messages were continuously sent from the ship to

mainland in order to ensure that the signals were being transported. By doing so, if anything was

to happen with the cable, engineers could figure out where in the transportation process the

problem had occurred [4].

Another major improvement to this new cable was being able to detect even the faintest

signals transmitted through it. For this, scientists turned to Kelvin’s Galvanometer. This was a

simple contraption made of the telegraph wire, a kerosene lamp and a mirror. By attaching a

mirror to the wire and focusing the flame on the mirror, even the slightest movement of the wire

could be visible. This ingenious device could detect signals 1000 times fainter than any other

device that was around during that time [4].

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A Pioneering Technology:

The Transatlantic Telegraph Cable became the pioneer in international communication.

In 1870, four years after the successful voyage, with the participation and help of the Great

Eastern, an all-sea cable route to India was completed. In the year after, another voyage was set

out which enabled the telegraph network to extend out to the Empire in the Far East and

eventually to Australia. Later, in 1866, Florida and Cuba were connected. In 1874, using a 5386

km long wire via the Cape Verde Islands, Portugal and Brazil were connected as well [1].

Not only did the number of cables across the globe increase, but also their speeds

increased too. The original cable was very slow and it was only able to transmit a few words per

hour. The 1866 cable was a bigger improvement and was able to transmit 6-8 words per minute.

In the later decades, with Oliver Heaviside’s development of the transmission line theory and the

telegrapher’s equation, great improvements were made to the speed of the transmission [1].

In 1928, with all these new theories, equations, and the right kind of materials such as an

improved loading using a nickel-iron magnetic alloy, an improved insulation, and automatic

transmitting and receiving equipment, a 400 per minute message was able to easily transmit

between two sources [1]. With the development of cable technology, it was time to solve a new

problem; transmitting speech across the Atlantic. In 1901, Guglielmo Marconi, the father of long

distance radio transmission, accomplished the first transatlantic speech transmission. This

resulted in radio transmission being continually developed. However, due to technical problems

and worldwide catastrophes, it was not until 100 years after the first telegraph message that

transatlantic telephone cable service was developed. It is important to note that submarine cables

still played a major role in communication as radio bands were unstable because of seasonal and

daily variations [1].

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Conclusion:

The successful transportation and usage of the Transatlantic Telegraph Cable not only

proved to be a great business venture, it also became the pioneering technology for modern

worldwide communication. Through the trials and errors made during the process of establishing

transatlantic communication, mankind developed some of the core laws for electromagnetics.

This in turn made it easier and more feasible to create better communication channels which

would eventually lead to wireless communication.

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References

[1] Schwartz, M.; Hayes, J., "A history of transatlantic cables." Communications Magazine,

IEEE , vol.46, no.9, pp.42 - 48, September 2008.

[2] Cookson, G. “The TransAtlantic telegraph cable: Eighth wonder of the world”. History

Today, vol. 50, no. 3, pp. 44-51, March 2000.

[3] Bowers, Brian, “The first Atlantic telegraphs." Proceedings of the IEEE , vol. 88, no. 7,

pp.1131 - 1133, July 2000.

[4] Public Broadcasting Service (PBS). “The Great Transatlantic Cable.” Internet:

http://www.pbs.org/wgbh/amex/cable/timeline/index.html, November 30, 2004 [March 6,

2013].

[5] Giancoli, Douglas. “Electric Currents and Resistance,” in Physics for Scientists and

Engineers with Modern Physics, 4th ed., Upper Saddle River, New Jersey: Prentice Hall,

2007, pp. 658.

[6] Schils, René . How James Watt Invented the Copier. New York, NY: Springer New York,

2012, pp. 77-82.

[7] DiaDent Group Int’l. Inc. “Diadent Gutta Percha - Root Canal Filling Material - Material

Safety Data Sheet.” Internet: http://www.net32.com/images/prodinfo/a/diadent-mfg-inc-

gutta-percha-pts-cc-spillproof-fine-med-100-bx-102-605.pdf, July 1, 2009 [March 26, 2013].

[8] Woods, Robert O. "A Cable to Shrink the Earth." Mechanical Engineering, vol. 133, no. 1,

pp. 40-44, Jan 2011.

[9] The Free Dictionary by Farlex. “Electrolyte.” Internet:

http://www.thefreedictionary.com/electrolyte, 2013 [March 27, 2013].

[10] Routledge, Robert . A popular history of science. California: University of California

Libraries, 1881, pp. 553-560.