|
The knowledge that steam could produce energy is about 2000 years old. An Egyptian engineer called Hero made a machine called "aeolipile" in which steam drove round a metal sphere. The aeoliopile was a toy with no practical use, but it showed that steam could be a source of energy.
The modern history of steam power began with a French scientist, Denis Papin (1647-1712). He invented the pressure cooker and a simple steam pump to provide the power of fountains. In 1690 Papin had the idea of building an engine in which steam would raise a piston inside a cylinder, creating a vacuum as it rose. This was the principle of later steam engines, but Papin never managed to make an engine that worked.
The miner's friend
The first successful steam engine arose out of the urgent need to pump water out of flooded mine shafts. In 1698, an English engineer, Thomas Savery (c.1650 1715), invented a steam pump. He called it the \'Miner\'s Friend\'. It had a cylinder which was filled with steam from a boiler. When the cylinder was cooled by pouring cold water on the outside, a partial vacuum was created. The vacuum drew water into the cylinder from the mine shaft. The Miner\'s Friend would pump water up only about six metres. If the water was any deeper, the engine became unsafe and sometimes even blew up. This engine used a huge amount of coal to raise steam.
Opposition to steam
To people who had been used to the quiet and leisurely pace of horse-drawn transport, the speed, power and noise of steam locomotives was terrifying.
The first victim of a railway accident was a British cabinet minister, Sir William Huskisson (1770-1830). At the opening of the Liverpool and Manchester Railway in 1830, he stepped into the path of the oncoming train and was killed.
Some even believed that rail travel could be dangerous. ln the 1830s, an eminent Irish scientist, Dr Dionysius Lardner (1793 1859), warned that travelling at a speed of forty eight kilometres per hour could make the brain fall apart. In Britain, Queen Victoria was persuaded to make a train journey from Windsor to London in 1842 to show that rail travel was safe.
Country people in particular were opposed to railways. They had good reason, because the noise and smoke of trains ohen frightened livestock grazing by the line and made horses throw their riders. Another problem was that sparks from locomotive chimneys came down in line-side fields and set fire to growing crops. But farmers later found that they benefited from railways, because trains could get their goods to market more quickly than before.
Improving the engine
At this point, the best-known name in the history of steam comes into the story. James Watt (1736-1819) was a Scottish instrument maker and repairer working at the University of Glasgow. In 1763, he saw a Newcomen engine for the first time when the university sent a model in for repair. Watt was a true scientist, always questioning and experimenting. Soon he was working on ways to improve the efficiency and cut the fuel consumption of the Newcomen engine.
Watt\'s first improvement was to separate the heating and cooling stages of the engine\'s operation. Having to heat the water and then cool it in the same cylinder made the Newcomen engine slow and was also the main cause of its heavy use of fuel. Watt designed an engine with a separate condenser where the cooling process could take place. Meanwhile, the cylinder stayed hot all the time. This meant that there was no pause while the cylinder reheated.
The addition of a condenser was only one of the improvements made by James Watt. Of the others, the most important for the future of transport was his introduction of a set of gears which he called \'sun and planet\'. Until then, steam engines could produce only an up-and-down movement. The piston made to rise and fall by steam in the cylinder was attached to a beam which also rose and fell. Watt\'s sun and planet gear enabled the piston to turn a gear wheel, the \'planet\', which meshed with a second gear, the \'sun\'. The \'sun\' was connected to a wheel shaft and made it turn.
Watt had found the way to change the up-and-down movement of the piston into a rotary movement. In other words, Watt\'s sun and planet gears could make steam engines turn wheels. The possibility of steam-powered transport had at last become a reality.
On the rails
This was the first time that a steam train had travelled on rails, but the idea of using rails to provide a more even surface than the bumpy, rutted roads of those days was not new. Wooden tramways had been used for horse-drawn transport in coal mines for at least 200 years. About 1800, some of these wooden tracks began to be replaced by longer-lasting cast iron rails. It was Trevithick\'s idea of bringing together the iron tramway and the steam locomotive that marked the launch of the railway age.
At first, progress was slow. In 1808, Trevithick built a small circular railway track in London to demonstrate his new locomotive, Catch-Me-Who-Can. Plenty of people came to see it, but the railway was still seen as a toy, not as a serious means of transport. Trevithick lost heart and turned to other interests.
Meanwhile, steam locomotives had caught the attention of another Englishman, George Stephenson (1781-1848). In 1814, he built his first locomotive for the colliery where he was the engineer. Eleven years later, his engine Locomotion hauled the first railway train on the newly-built line, forty-two kilometres long, between Stockton and Darlington in northern England. This was the first railway in the world open to the public, with regular services in each direction. But people were still unsure about the safety of steam travel. Locomotives were used to haul coal trains on the Stockton to Darlington line, but passenger services were horse-drawn.
Railway madness
Railways made a vast difference to the lives of ordinary people. Travel was faster and easier than it had ever been. Soon, people were living at a distance from their work and commuting each day by train. The railways made travelling for holidays possible. They also made the transport of goods from place to place easier and cheaper. Fresh meat and vegetables, milk and other dairy products became easier to buy. New towns grew up close to the railway lines. Builders no longer had to depend on local materials, and farmers could transport their cattle to market by train instead of driving them slowly along the roads.
Army generals, too, were quick to realize that railways were an efficient method of transporting troops. The first use of railways in war was in the Crimean War of 1853 to 1856 when Britain and France fought Russia. A temporary railway was built to carry British troops into battle and to evacuate the wounded.
Steam conquers the world
Within fifty years of the opening of the first steam¬powered railway, the steam locomotive had conquered almost the whole world. By 1869, it was possible to cross the United States from the Atlantic to the Pacific by rail. The east-west link across Canada was opened in 1887. India\'s and Australia\'s first railways opened in 1854, and Africa\'s in 1870. Some of these lines gave links with the outside world to places that had been almost completely cut off before.
Most of the world\'s railways now operate with diesel or electric locomotives, but if it had not been for the pioneers of steam many would not have been built at all.
Steamships
Soon after the invention of the steam engine, inventors began to wonder if steam could free sailors from the uncertainties of relying on the wind for power. American engineers led the way in the development of steam for shipping. So it came that the first steamships were built about 1750.
Steam shrinks the world
Just as railways opened the way to the interiors of the continents, so steamships brought the continents closer together. Farmers and manufacturers found new markets for their products overseas, carried quickly and reliably by steamer. The steamship was also responsible for large movements of populations, as millions of people from Europe crossed the oceans to begin new lives in North America, Australia and New Zealand.
Within less than a hundred years, steam had changed the world. In 1800, the fastest means of transport on land had been on horseback. At sea, travellers had depended on the way the wind blew. By 1900, there were few large towns or cities in the world without a railway station, and travel by rail had become fast and cheap. At sea, a network of regular steamship services carried passengers and cargoes across the world.
|
