James Watt. The inventor of the universal steam-engineCategory: Famous people
James Watt was born on January 19, 1736, at Greenock in Scotland, where his father was a shipwright. Jamie, as his parents called him, was not at all strong. He suffered from terrible headaches and this was naturally a great handicap to him both in play and later in work.
He could not start his schooling at as young an age as most children did, so his mother taught him to read, and his father taught him writing and arithmetic. He had a very good memory and a natural love of work.
He liked mathematics and was also fond of designing and making things. For hours he would dismantle his toys and then rebuild them to his own design with the help of a small set of carpentry tools given to him by his father.
When James was able to go to school he was sent to a private school; and he also received private lessons. He learnt a lot of subjects, and became good at languages as well as at mathematics.
When James was fourteen he was given the famous book by Isaac Newton called Elements of Natural Philosophy. He found the book so interesting that he read it many times and spent much time thinking about it. He then started spending his free time on experiments. He made a small electrical apparatus with which he gave his friends shocks that made them jump. At the same time he studied how steam could be condensed. Though only fifteen, he was already beginning to acquire knowledge that was very important for him later when he began to design the steam engine. Soon after reading Newton’s book on natural philosophy, James began to read books on other scientific subjects— chemistry, medicine and anatomy.
James Watt, as a boy, spent much time in his father’s work-shops. He learnt about elementary mechanics and about fitting out ships.
His father always kept a good stock of telescopes, quadrants, and other optical instruments. James showed an especial interest in these instruments. He spend hours dismantling them to study how they worked and then carefully reconstructed them. This led him to take an interest in astronomy. Sometimes he went to a nearby hill and studied the stars through ships’ telescopes.
When James was eighteen he decided to become a professional instrument-maker, and in June 1754 he went to live with his uncle and aunt in Glasgow hoping to perfect the trade there. But there were so few qualified instrument-makers in those days that James could not find anyone in Glasgow able and willing to teach him. So he set off on horse-back for London.
After some time James managed to persuade an instrument-maker to give him a year’s instruction for twenty guineas. He found his training very hard and tiring. He worked from early morning till late in the evening.
In a few months, however, he could make many things and towards the end of his training he told his father, “I think I shall be able to get my bread anywhere, as I am now able to work as well as most journeymen, though I am not so quick as many.”
Watt bought a few tools and returned to Glasgow to establish himself as an instrument-maker in that town.
At Glasgow University
It happened that Glasgow University had just received valuable instruments for equipping a new observatory. These instruments needed cleaning and putting into good working order, and Watt was given that job. His work on the instruments was so good that he was allowed to call himself “mathematical instrument-maker to the University”.
When he was twenty-one Watt was asked by a professor of medicine to make instruments that the latter needed for his medical experiments. Then he began to make quadrants and sell them at a much lower price than that asked by most instrument-makers. He also made musical instruments—organs, violins, flutes, and guitars.
Once Watt was asked to repair a small working model of an atmospheric-steam engine that was used for demonstration at engineering lectures at the university.
The original full-size engine which this model represented had been built in 1702 by the famous engineer Thomas Newcomen to pump water out of coal-mines.
Newcomen’s engine was the first practical attempt at designing a steam-engine, or fire-engine, as it was then called. It was very primitive and did not look like the steam-engines of today.
Watt soon started to think out ways how to improve its efficiency. He made a few scientific experiments in the hope of discovering the causes of its faults.
The results of these experiments showed him that Newcomen’s engine, like the other atmospheric-steam engines of that time, was founded on the wrong principle. He understood that in order to make the best use of steam, it was necessary—first, that the cylinder should he always as hot as the steam which entered it; and, secondly, that when the steam was condensed, the water to which it was reduced and the injection water itself should be cooled down to 100 degrees.
It took Watt two years to find a way of putting his new theory into practice; but one Sunday afternoon in April 1765, while he was out for a walk, he suddenly found the answer to his problem. It occurred to him, he wrote later, that if communication were opened between a cylinder with steam and another vessel which was without air or fluids, the steam, as a fluid, would go into the empty vessel, and continue so to do till it had established equilibrium; and that if that vessel were kept very cool by an injection or some other way, more steam would continue to enter till the whole was condensed.
Watt had made a great discovery: the using of a separate condenser in an engine for condensing the steam into water, so that the temperature of the cylinder was not lowered at each stroke of the piston.
When he returned home, he took an old syringe and a few other things, including one of his wife’s thimbles and made a model engine to test his ideas. He introduced another new idea into his model in addition to the separate condenser: he did not leave the top of his cylinder open and he did not rely upon atmospheric pressure to drive down the piston. He closed the top and arranged the piston to be driven down by steam pressure. So the cycle was completed and the piston was operated by steam only.
Though he had managed to make a successful model without much difficulty, lie found it very difficult to construct a full-size engine based on his principles. He could not make his piston slide smoothly up and down the inside of the cylinder. The steam percolated between the piston and the cylinder and reduced power. Eventually, Watt managed to solve this problem to a certain extent: he put a mixture of pasteboard, cork, tow and horse-dung over the inside surface of the cylinder; but it was several years before he thought of this, and by that time his costly experiments had run him heavily into debt.
At a Factory in Birmingham
Once, when Watt was on his way back from London to Scotland, he visited a large factory in Birmingham which had been built a few years before. This factory, described as “the largest in England”, had over 1,000 workmen, who made “all sorts of works … even astronomical clocks”.
Watt was much impressed with the factory, but he saw one serious weakness. The mechanical equipment used in the factory, such as it was, was driven by a water-wheel, in much the same way as the country flour mills were driven. But the stream providing the water ran so low in dry weather that production was often brought to a standstill. Watt thought that his new steam-engine could be used there; and in May 1774 Watt and his two children (his wife had died three years before) went to Birmingham.
James Watt was not thirty-eight. It was eleven years since he had first become interested in building a steam- engine, but he had still not perfected his engine and he had not been able to make use of it at all for industrial purposes.
One reason why his engine was not fully efficient was that the cylinder bore was not a perfect circle; it was a little oval. This meant that nothing could entirely prevent the escape of steam round the piston. When Watt explained this difficulty to his partner, the latter immediately arranged to have better cylinders especially bored for him.
New cylinders were a great improvement on those that Watt had used before, and with their help he could build an engine that at last really was efficient. “The fire-engine that have invented is now going, and answers its purpose better than any other that has yet been made,” he wrote to his father.
His engine was soon drawing up water from the mines from a lower level than had ever been reached before.
Once it was known how successfully the engine was working in the Cornish tin-mines, more and more orders from other parts of the country began to come. One order was from France for an engine for supplying Paris with water.
Watt did not work on his engine only. He made several other inventions of a different kind. The most important of them was a copying machine. He invented this machine in the first place to help him with his correspondence and other written work.
This is how the machine worked. A letter or manuscript was written in a special ink that took a long time to dry. Then thin sheets of paper were pressed in turns over the original script until ink had successfully penetrated the paper and had left a clear impression of the writing. Several copies could be taken very quickly in this way, thus saving, the writer hours of work.
Watt’s copying machine was used all over the country for about 100 years—until the typewriter took its place.
He also invented a method of bleaching, a machine for drying linen, and an instrument for determining the specific gravities of liquids.
In October 1781 Watt made a still better engine that could do much more than merely pump water out of mines. This was a rotative engine. It could run machines, a thing no steam-engine had ever been able to do before. This was a great invention at that time. Watt took some time to improve his new rotative engine. After he perfected it all kinds of industries began to use it. In fact, it became the basis of industry: the motive power that drove the wheels of the various machines used in industry. It could do many things.
But there was one thing that Watt’s engine could not do: propel itself and so drive a train. Walt thought to try to design a locomotive as well as his stationary engine, but he soon gave up the idea of designing a locomotive.
In 1800, when James Watt was sixty-four, he retired. But he was by no means idle in his retirement. He fitted up a room in his house as a workshop, and shut himself away in this room for hours at a time making experiments or designing something. One invention that occupied his attention was a machine for copying sculptures.
When he came out of his workshop, he usually settled down by the fire with a book, to improve his general knowledge. He read anything that he could lay hands on, but he was particularly interested in reading about music, medicine, law, and architecture, and, of course, about engineering and scientific subjects. He often continued his reading till late at night.
As well as reading and experimenting, Watt received many visitors to his own home. He was an excellent conversationalist, and people paid great attention to everything that he said.
James Watt lived to the age of eighty-three. He received many honours in recognition of his valuable work. He was elected a Fellow of the Royal Society of both London and Edinburgh. Glasgow University, the university where he began his successful work, conferred on him the honorary degree of Doctor of Law; and France made him a member of her famous Academy of Sciences.
He liked very much to explain engineering problems to anyone, particularly young people, who wished to consult him, and he was consulted very often by people of all ages.
On August 19, 1819 James Watt died at his home. A few years later a monument was erected to his memory in Westminster Abbey.