A submarine communications cable is a cable laid on the sea bed between land-based stations to carry telecommunication signals across stretches of ocean. The first submarine communications cables, laid in the 1850s, carried telegraphy traffic. Subsequent generations of cables carried telephone traffic, then data communications traffic. Modern cables use optical fiber technology to carry digital data, which includes telephone, Internet and private data traffic. 

Modern cables are typically about 1 inch (25 mm) in diameter and weigh around 2.5 tons per mile (1.4 tonnes per km) for the deep-sea sections which comprise the majority of the run, although larger and heavier cables are used for shallow-water sections near shore. Submarine cables connected all the world's continents except Antarctica when Java was connected to Darwin, Northern Territory, Australia in 1871 in anticipation of the completion of the Australian Overland Telegraph Line in 1872 connecting to Adelaide, South Australia and thence to the rest of Australia. 

After William Cooke and Charles Wheatstone had introduced their working telegraph in 1839, the idea of a submarine line across the Atlantic Ocean began to be thought of as a possible triumph of the future. Samuel Morse proclaimed his faith in it as early as 1840, and in 1842, he submerged a wire, insulated with tarred hemp and India rubber, in the water of New York Harbor, and telegraphed through it. The following autumn, Wheatstone performed a similar experiment in Swansea Bay. A good insulator to cover the wire and prevent the electric current from leaking into the water was necessary for the success of a long submarine line. India rubber had been tried by Moritz von Jacobi, the Prussian electrical engineer, as far back as the early 19th century.

Answer the following questions:
1. When were the first submarine communication cables placed?
2. Where do they lay?
3. What kind of communications did they initially carry?
4. What technology do they currently use?
5. Can they provide internet service?
6. When was the telegraph first introduced?
7. By whom?
8. Did Samuel Morse believe in a oceanic submarine line?
9. Crossing which ocean?
10. What year did he express his support in the project?
11. What year did he perform a test of his own?
12. Which body of water did he use?
13. Who else performed a similar test?
14. Where?
15. How wide are modern cables?
16. Do they reach all of the continents?
17. Which one is excluded?
18. Which continent was the most recent to be connected?
19. What year did it join?
20. Where did it connect?

Numbered answers:
1. 1850s
2. on the sea bed
3. telegraphy
4. optical fiber
5. yes
6. 1839
7. William Cooke and Charles Wheatstone
8. yes
9. the Atlantic
10. 1840
11. 1842
12. New York Harbor,
13. Wheatstone
14. Swansea Bay.
15. 1 inch
16. no
17. Antarctica
18. Australia.
19. 1872
20. Darwin