Part 2 – Talking Across Seas

The telegraph network grew quickly to link the major towns and cities of Britain, although it took much longer before the smaller towns and villages were connected. Similar networks were developing in Europe and particularly rapidly in the United States. The potential for long-distance communication if these national networks were linked was soon realised. In mainland Europe this was not difficult, as countries were separated by land borders, but Great Britain was in danger of becoming increasingly isolated from the communications revolution.

Early telegraph systems used a single wire, the circuit being completed through the earth. The difficulty in crossing seas lay in insulating the single core of the cable to prevent a short circuit through the sea water and so to the earth. Various substances were tried, including tar, but none was totally effective.

The problem was eventually solved by the use of a material known as gutta percha. This is a form of rubber obtained from the gutta percha tree, a native of South East Asia. The gutta percha was collected from trees scattered throughout the forests which made it very expensive. It was not until the end of the nineteenth century that the commercial rubber plantations were set up to provide a plentiful and cheap supply.

Samuel Morse was also grappling with the problem of running telegraph cables under water. In 1842 he successfully laid an underwater cable from Castle Garden to Governor’s Island in New York Harbour. He then went on to predict the feasibility of submarine telegraph cables and even of a transatlantic link, which must at the time have seemed utterly impossible.

The English Channel

The first attempt to lay a telegraph cable across the English Channel was not without its critics. One opponent laboured under the mistaken belief that messages would be conveyed by jerking the cable and concluded that it would be impossible to drag the cable across the rough bed of the Channel. Another wrote

The restless sprit of modern invention, not content with guiding the mysterious power of which we have been speaking, both above and beneath the surface of the earth … proposes next to join the shores of England and France by means of a Submarine Telegraph, across the Straits of Dover. That such an undertaking is possible, there is but little doubt; but the question is, would it be worth while to attempt to carry it out.

[The Electric Telegraph, Peter Progress, London, 1847]

But then the prospect of a man walking on the moon was at one time viewed with equal scepticism. Fortunately, the champions of the scheme to link Calais with Dover, retired antiques dealer, John Brett, and his brother Jacob, were not to be daunted by such kill-joys. Unfortunately, they provided their opponents with ample ammunition as their plan was both hurried and ill-conceived. Their cable contained a single core of copper wire insulated by a layer of gutta percha just 6mm (a quarter of an inch) thick. They assumed that once the cable lay on the sea bed it would be quite safe and only those sections nearest the shore would need to be protected with a sheath of lead.

When it came to laying the cable it was discovered that it was too light to sink satisfactorily and so lead weights had to be attached at intervals. However, by the evening of 28 August 1850 the cable was landed at Cape Grinez and an automatic printer was connected. But the first messages emerged as a jumble of letters. What no one realised at the time was that when submerged, the cable behaved in a quite different way from when it was suspended from poles and surrounded by air. When a cable is surrounded by sea water (which conducts electricity) the rate at which it can transmit messages decreases. Had the telegraphists transmitted the message more slowly there would have been no problem. Eventually a needle instrument was connected and some words were deciphered.

The success of the venture was fleeting. By the following morning all communication ceased. The cause of the failure was eventually traced to a French fisherman who had brought up part of the cable in his nets, cut off a portion and proudly exhibited it at Boulogne as an example of a rare seaweed with a gold centre.

The following year the Bretts financed the laying of a second cable. This one was a considerable improvement on the first: there were four copper conductor wires each covered with gutta percha and twisted together and filled with tarred hemp. This was enclosed in an outer casing of tarred cords re-inforced with iron wires. In November 1851 the cable was opened to the public.

Spanning the Atlantic Ocean

Once it had been established that a submarine cable could work, minds turned to connecting countries separated by wider stretches of water. The language and historical bonds between the United States and Britain made the Atlantic an obvious choice. But there was a vast difference between the 24 miles of water that separates England from France and the 1600 miles of the Atlantic Ocean.

Glass Elliott cable works, Greenwich, London, 1850’s. Glss Elliott made the cable which was laid across the Atlantic.

The first attempt was made in 1857 by the newly established Atlantic Telegraph Company. The cable consisted of seven copper strands twisted together to make a single core and surrounded by three layers of gutta percha so that if one layer was punctured the remaining two would ensure effective insulation.

No one, it seemed, had considered the fact that the final weight of the cable would be 2,500 tons more than any ship could carry. The cable was cut and shared between two warships, the Niagara and the Agamemnon, loaned respectively by the American and British Governments.

The vessels would sail together from Ireland and the cables joined in mid Atlantic. The ships set sail from Valentia Harbour, on the south west coast of Ireland, on 6th August 1857 on a voyage that was beset with problems. After only a few miles a fault was discovered and the cable already paid out had to be checked and, when the fault was found, repairs made. Everything proceeded well until 335 miles out when it was noticed that the cable was paying out rather too quickly. The brake was applied, rather too suddenly it turned out, and the cable broke. The ships returned to England and the remainder of the cable was stored against the hope that a second attempt could be made.

For the second attempt in June 1858, it was decided that the two ships should meet in mid Atlantic, splice the two ends of the cable and then lay it in opposite directions. On the way to the rendezvous point the ships were caught in one of the worst storms ever recorded in the Atlantic. However, they rode it out and cable-laying began. There were several failures caused by the cable snapping but eventually the two ends of the cable were landed at Valentia and Hearts Content in Newfoundland, a distance of 3782km (2,350 miles). On 16th August 1858 Queen Victoria sent a message to President Buchanan. The message took sixteen and a half hours to transmit.

Text of Queen Victoria’s telegram

The following day the first commercial telegram was sent and amidst the jubilations the future looked bright for the Atlantic Telegraph Company.

However, disaster struck two weeks later when the line went dead and no further messages were received. No one knows for certain why the 1858 cable failed but it is likely to have burned out. After travelling along 2,350 miles of submerged cable the signals received at the far end were so tiny they required very sensitive instruments to register them. In an attempt to magnify the strength of the signal the voltage was increased. Just before the cable failed it was carrying up to 2,000 volts. The effect of such a high voltage probably melted the thin copper core.

Public opinion, fickle at the best of times, turned against the submarine telegraph, and there were even rumours that the entire scheme had been a hoax. This change in attitude made it much more difficult to raise the money to finance another attempt, which the promoters were adamant there should be.

Towards Success

A further attempt was made in 1865 and time was spent designing an improved cable, much stronger and more electrically efficient than that used in 1858. 2,600 miles of cable were manufactured weighing 7,000 tons, which in itself presented a problem. There was only one ship which could carry such a load, the Great Eastern, which at that time was lying idle.

Hopes were high when, on 23rd July 1865, the Great Eastern left Valentia bound for Newfoundland. The cable laying was beset by problems and progress was slow but after 1,300 miles had been paid out the test signals from Valentia remained perfect. Then a fault was noticed and the cable cut. While it was being manoeuvred around to the bows for repair it snapped and fell to the bed of the sea.

Undaunted, the crew made several attempts to retrieve the cable using a grapnel. One drag brought the cable to the surface but the weight was too much for the iron hawser wire to bear and it snapped. The supply of iron hawser wire was exhausted so the Great Eastern returned to Britain with the remainder of her cargo.

The following year yet another attempt was made. Various modifications were made to the Great Eastern as a result of lessons learned from the 1865 expedition. Another 1,990 miles of cable was ordered. The Great Eastern sailed once again from Valentia on Friday, 13th July 1866, hardly an auspicious day. Laying the cable took fourteen days and was uneventful. The Great Eastern landed the cable at Hearts Content where it was connected to the existing land lines which linked it to New York. America and Britain were finally united by a telegraph cable. On the first day the cable earned a staggering one thousand pounds.

Not content with one major triumph the Great Eastern immediately set sail again for the mid Atlantic. The lost end of the 1865 cable had been marked by buoys and the crew began dragging the sea bed with hooks to retrieve it. After thirty attempts the cable was finally hauled on board and spliced. The ship turned and laid new cable back to Newfoundland. And so in the space of a few weeks there were two working telegraph cables.

Preliminary Activities

• Ask pupils to locate the English Channel, the Atlantic Ocean, Ireland, France and Newfoundland using an atlas.
  
  
• Ask pupils to speculate on what problems they might face in making a laying an undersea cable.
  
  
• Pupils should know that before the first underwater cables were laid there were extensive land based telegraph networks, especially in Western Europe and the United States. Unless a way could be found of laying wires across seas these continental networks would remain isolated from each other.

Extension Activities

The Earth as a Conductor

Children learn that an electrical circuit requires metal wires and they naturally assume that this is always the case.

They find it very difficult to accept that some circuits such as the Atlantic telegraph (and indeed most early land telegraphs) used just one wire. The circuit was completed by using the earth as the return `wire’. Although the earth does allow an electric current to flow it is a poor conductor and the resulting current is too small to light a bulb for instance and so some other way has to be found of showing it is there.

By winding a wire around a compass you can make a very simple but effective current detector. When an electrical current flows through the wire the compass needle will move; even a very small current will cause the needle to move.

• pocket compass
  
  
• one metre length of single core insulated wire
  
  
• switch (optional)
  
  
• short length of single core insulated wire
  
  
• two large nails
  
  
• small 9 volt battery
  
  
• plastic bowl full of damp earth (or the experiment could be set up outside)
  
  

The same equipment can be used to test if tap water conducts electricity, and what effect the addition of salt has.

The Cable Laying Game

Play the cable laying game. You will need one dice.

The game can be played by two, three or four players.

Cut out the cable laying ships and use felt pens to make each one a different colour.

You can choose whether to begin laying your cable from either Valentia or Hearts Content. The game begins with the first person to throw a six. Move the same number of circles as there are dots on the dice. If you land on a shaded circle read what you have to do. To land the cable you must throw the exact number needed. If you need a 3 and you throw a higher number then you cannot move. If you throw a 1 or a 2 you may move closer to the shore.

Insulation

Pupils may not be aware why electrical wires need to be insulated. Ask them to make a circuit containing a bulb and a battery using uninsulated wire (fuse wire would do). Tell them that the two wires must not touch each other. If they then make the wires touch they will cause a short circuit and the bulb will go out. They should only do this quickly as the bare wires can get quite hot.

Now ask them to devise a way of insulating the bare wires so that a short circuit cannot occur. They might, like Cooke and Wheatstone, wrap paper around the bare wire, although they are likely to come up with some much more ingenious solutions.

Keeping it Waterproof

A submarine telegraph cable needs to be waterproof. If it is not then the current will flow through the sea water and to earth, causing a short circuit. Pupils could design a test to find out what materials are impervious to water. They will need to assemble a range of different materials (paper, wood, plastic, textiles, aluminium foil, etc.).

They could then devise a method of making a material, such as paper, waterproof.

Materials and Water

Pupils could investigate the effect of water on a range of different materials (wood, steel, paper, plastic, textile). This might lead to an investigation into why steel rusts -what factors are responsible? How can steel be prevented from rusting?

The First Transatlantic Telegram

Read Queen Victoria’s message to President Buchanan.

Text of Queen Victoria’s Telegram

If at First You Don’t Succeed

Several attempts were made to lay a telegraph cable across the Atlantic Ocean. After each one failed it became more difficult to persuade people to invest their money in another attempt.

Imagine you are one of the Directors of the Atlantic Telegraph Company. Write an advertisement for a newspaper that will persuade people to lend you money for another try.

Write your own advertisement

Where Next?

Your company has finally laid a telegraph cable that works across the Atlantic Ocean.

The British Government is impressed with the Atlantic Telegraph and would like telegraph cables to link London with all the countries in the Empire.

Your company has enough money to lay three more cables. Mark on the map where you will lay your submarine cables and show which countries you will link to London. Why did you choose these countries?

Cabling New York

This Atlantic Telegraph Company document shows how much it would cost to send a telegram to America when the Atlantic cable was laid. To help you the costs of some things in 1865 is given.

Do you think it cost a lot to send a telegram?

How did figures have to be written?

Why do you think this was?

Why did a message in code cost twice as much?

For £20 you could send a message of up to twenty words (including the address, date and signature) and no more than 100 letters. Why do you think the number of letters was limited?

You are going to send a telegram to your aunt in America telling her that you are coming to visit her. You will travel on the steamship Valiant and will arrive in New York on July 8th. You would like her to meet you.

You have exactly £20 so make sure you do not use more than 20 words. Remember that the name, address and date all count as words. Count the number of letters in your message to check you have not used more than 100.

Your aunt’s name and address is:

You do not have to use the whole address – just the parts which will make sure the telegram can be delivered.

Packing Your Trunk

You work for the Atlantic Telegraph Company. They have asked you to go to Newfoundland to work in the telegraph office for three months. You will be home again in time for Christmas. It can get very cold in Newfoundland in the winter. What should you take with you? Make a list of all the things to pack in your trunk.

You need to know that summers in Newfoundland are quite mild but the winters are very cold.

Atlantic Telegram Charges

Look at the table of how much things cost in 1865. This will tell you whether sending a telegram to America was cheap or expensive.

Can you think of some reasons why the cost sometimes went up and sometimes went down? (During the second half of 1869 there was strong competition from a French cable company and charges were reduced to attract business.)

PART 1: Whispering Wires

PART 2: Talking Across Seas

PART 3: The Great Eastern