In all his activities, man now makes use of a lot of ma- chines. Although most of these are of quite recent origin, afew simple ones have come down from very ancient times

The arrow, for example, was well known to man since prehistoric times, since it was only by hunting that he could get his food. The wheel, one of the greatest inventions eve; made by man, is also of prehistoric origin. A two-wheeled carriage is represented widely in his art and literature. The lever is probably of equally ancient origin. It is mentioned by the Greek philosopher Aristotle as a means of lifting a great weight by using a very small force.

After Aristotle there was little change in the number and kind of machines in use for nearly twenty centuries. Since then one new device after another has come to displace others that were less efficient only to be displaced in turn by other devices still faster or better. Let us have a look at a few of these changes.

In going from his home in Mount Vernon to New York to be inaugurated as the first President of America, Washington travelled in a horse-drawn carriage. The roads were extremely difficult to travel. The travel of a little over two hundred miles required seven hard days. That is a speed of about 35 miles a day. Men could travel by land in only two other ways—on foot and on horseback. Within half a century of that time a few short railways had been built in three different parts of the country. At first the trains were drawn by horses; in 1831 the first steam locomotive to be used in America was put into use. The "iron horse" soon proved its efficiency. New lines were designed and old ones extended. A speed of 35 miles a day had given way to regular schedules exceeding 35 miles an hour.

In the first decade of the present century it was thought that the limit of desirable speed had been reached. But the substitution of diesel and electric engines for steam engines and numerous other improvements have shown that much higher speeds may be easily achieved. Modern transportation uses electricity in many ways. Without it transportation, as is known today, could not exist.

On the other hand, modern life would be unthinkable without modern means of transport. To reach any part of the world is a matter of hours or days, while a century or two ago it took weeks, sometimes even months or years. Nobody could have imagined then the speed of our airplanes.

Now let us have a look at a few facts and figures concerning Moscow transport. According to historical documents one-horse cabs appeared in Moscow as early as 1586. Public trans­port was established only in the forties of the last century. The first lines for horse-drawn trams were built in 1872 and those for mechanized trams in 1903. Four years later there were already 800 trams in operation. The first eight buses appeared in the city 40 years ago, while today there are more than three thousand in operation. By the way, a Muscovite makes about 800 trips in buses, trolley-buses, the metro, and trams an­nually.

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