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135
The water transport in ancient times developed most rapidly on great rivers.
The ancient Romans used vessels to carry their armies and supplies to colonies.
These ships, usually called galleys, continued to be used in the Mediterranean till
1750.
The introduction of the magnetic compass allowed long voyages to be made
with much greater safety. At the end of the 15
th
century, sailing vessels are known to
have carried men from Europe to America and round Africa to India. The middle of
the 19th century proved to be the highest point in the development of sailing ships.
Steam and Motor Ships, One of the earliest steamboats is known 1 have been
tested at the end of the 18th century. The first steamship to cross the Atlantic was the
Savannah, 98-foot ship built in New York, which mad the crossing in 1819. Like all
the early steamships, it had sails as well at paddles. By the middle of the 19th century
it became possible to built much larger ships for iron and steel began to replace
timber.
The rapid increase in the size and power of ships was promoted by the
industrial revolution. The industrial countries produced great quantities of goods
which were carried to all parts of the world by ships. On their return voyages, the
ships brought either raw materials such as cotton metals, timber for the factories, or
grain and foodstuffs for the growing population. During the same period, a great deal
was done to improve ports, and that permitted larger ships to use them and to make
loading and unloading faster.
Текст 8
GRAVITATION
Gravitation is a very important force in the universe. Every object has a
gravitational pull which is like magnetism. But, unlike magnetism, gravitation is not
only in iron and steel. It is in every object large or small; but large objects, such as
earth, have a stronger pull than small ones.
Isaac Newton, the great scientist of the seventeenth century, first studied
gravitation. When he was a boy, he often saw how apples fell to the ground. He
wondered why they fell towards the earth and why they did not fly up into the sky.
According to the law which he later produced everything In the universe attracts
everything else towards itself. The sun attracts the earth and the earth attracts the sun.
The earth attracts the moon and the moon attracts the sun. Although the bigger object
has the stronger attraction, all objects, in fact, have some attraction too but we do not
notice the gravitational pull of a book because the pull of the earth is very much
greater.
Why does the earth always move round the sun, and not fly off into cold space?
The sun's gravitation gives the answer. The earth always tries to move away in a
straight line, but the sun always pulls it back. So it continues on its journey round and
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