James Watt (1736-1819) was a great modern British inventor who was world-famous for his invention of a highly efficient steam engine.

Watt was born in Greenock, near Glasgow, Scotland. Glasgow is the center of the British shipbuilding industry. Watt's grandfather taught mathematics, and his father was an architect and shipbuilder who served as treasurer and alderman of the town of Greenock. He loves learning, has strong curiosity, and is extremely intelligent. In addition, he has learned a lot of knowledge about machine manufacturing since he was a child. Watt attended Greenock Grammar School, but dropped out due to illness. While he was recuperating at home, he studied hard on his own and read a lot of books on astronomy, chemistry, physics, etc. In 1753, his father went bankrupt in business, and Watt was forced to go to Glasgow to learn a trade. At that time, he was less than 18 years old. Two years later, he moved to London as an apprentice in a watch shop. Watt learned many skills in making instruments and machines here. Due to his diligent study and practice, he quickly learned to make complex instruments such as quadrants, compasses and theodolite.

At the age of 20, Watt suffered from severe rheumatism and had to go home to recuperate. After he got better, he wanted to start an instrument manufacturing business in Glasgow, but there were still exclusive guilds at that time. Because he had not left the apprenticeship, the local guild did not allow him to start a business. But there is always a path, so he was introduced by a friend and became an instrument repairman at the University of Glasgow. Here he met the famous chemist Professor Joseph Black and his student physicist John Robinson. The university was one of the few institutions of higher learning in the UK at that time, and the school had a variety of instruments and equipment. Here, he eagerly studied scientific theory and practical knowledge. In order to understand foreign scientific and technological trends, he learned French, Italian and German. He worked with Blake and other scientists to improve the barometer and hygrometer. Blake's latent heat theory had a particularly great influence on Watt, who later used it in his steam engine.

There was a popular story in the past that Watt was inspired to invent the steam engine when he saw a teapot boiling on the stove and the steam blew up the lid. This is too simplistic. In fact, people had recognized the role of steam long before Watt. In the 17th century, due to the rapid development of capitalist production relations, the demand for power increased day by day, and people's exploration of the use of steam power has achieved some practical results. In 1629, Italian Blanck invented a primitive steam turbine device. He used steam to push the impeller and drive the spring rod. In 1698, the Englishman Savery built a steam pump that could be used for mine drainage. In 1705, the Scottish blacksmith Newcombe built the first steam machinery of great practical value, called an atmospheric press, based on Savelli's invention. At that time, it was mainly used for mine drainage. After 1721, it was adopted in many mines in England and spread to continental Europe.

In the 1760s, Britain began the Industrial Revolution with the invention of the spinning machine and technological advances in other fields. The invention and application of a series of working machines called for a universal power machine that transcended natural forces. At this time, due to the invention and use of water turbines, clocks and other machinery, people have accumulated knowledge in mechanical manufacturing, mechanical transmission and metal processing. The widespread use of coke in the iron smelting industry has made great progress in iron and steel smelting technology. Manual The development of the factory has trained a large number of skilled workers, which prepared the technical conditions for the invention of the steam engine.

Watt worked hard to absorb the achievements of his predecessors and devoted himself to the development of steam engines. In 1761 and 1762, he conducted many steam pressure experiments at the University of Glasgow to study the relationship between the density, pressure and temperature of steam. In the winter of 1763 to 1764, he was responsible for repairing the model of Newcomb's atmospheric pressure machine. He repeatedly observed its operation and finally discovered the reason for the inefficiency of this machine. The Newcomen machine relies on the condensation of hot gas in the cylinder to create a vacuum. The atmospheric pressure drives the connecting rod connected to the piston to move, thereby generating power. After the cylinder is cooled, it needs to be reheated, which results in a large amount of waste of heat energy. Moreover, after the cylinder is condensed, the temperature is still high and the vacuum degree is low, which affects the performance of the machine. So Watt concentrated on solving this key problem.

Researching new steam engines was time-consuming and expensive. Watt soon exhausted his fortune and was heavily in debt. He was trapped in hesitation and depression, and almost stopped his research work. In order to make a living and support his family, he was forced to work as a surveyor and engineer, responsible for mapping the route of the Caledonian Canal. At this time, two visionary entrepreneurs came to his aid: John Roebuck and Matthew Bolton. In 1765, through Blake's introduction, Watt met Roebuck, who had just opened a coal mine at Borostones on the right bank of the Forth River and was in urgent need of a pump for mine drainage. Roebuck spoke highly of Watt's research work and was willing to provide funding to help him complete the development of the steam engine. So the two signed a contract, and Roebuck promised to repay Watt's debt of 1,000 pounds and be responsible for providing the funds needed to complete research and development and put into industrial production. Watt promised to give Roebuck two-thirds of the possible future profits as a reward. Roebuck's funding enabled Watt to continue his work on the steam engine.

After a series of experiments, Watt invented a condenser separate from the cylinder, and introduced the steam in the cylinder into the condenser for cooling. He worked hard to improve the machining accuracy of cylinders and pistons and enhance their tightness. In Newcomben's machine, steam was only an auxiliary force, and it actually relied on atmospheric pressure to do work. Watt's invention used steam to drive a piston. In addition, he used lubricating oil to improve the flexibility of the piston operation and added a thermal insulation layer outside the cylinder to maintain the necessary operating temperature of the cylinder. After this series of improvements, Watt built the first steam engine in 1769 and obtained a patent. The efficiency of Watt's steam engine was greatly improved compared to Newcomen's atmospheric pressure machine. The coal consumption was only one-quarter of Newcomen's engine, but the efficiency was increased by five times. However, the machine invented by Watt had only one cylinder, was very imperfect, and was prone to failure. It was put aside not long after installation. Soon, Roebuck's coal mines were shut down due to waterlogging. In 1733, Roebuck declared bankruptcy. It's true that misfortunes never come singly. Watt's wife died this year. Bolton helped him during this very difficult moment.

Bolton is the owner of a handicraft workshop manufacturing metal products in Soho, north of Birmingham, and has strong financial strength. Watt had known him some years earlier and had visited the Soho workshops in 1767. Bolton's business was booming and he needed an ideal power machine to equip his workshop. Roebuck happened to owe Bolton a debt of ￡1,200, and the latter proposed to forgive Roebuck's debt as long as he transferred his partnership contract with Watt to him. Thus began the cooperation between Bolton and Watt. In May 1774, Watt moved to Soho and settled with his first steam engine. He immediately set about improving his invention. Soon, the first steam engine was operating normally again.

While putting the steam engine into industrial production, Watt and Boulton continued to improve its design. At that time, there was still a lot of investment, little output, and high research and development costs. Bolton invested all the profits from the factory and the income from selling his wife's property into improving steam engines. Watt also benefited from the inventions of others in perfecting the steam engine. For example, the boring machine invented by John Wilkinson in 1775 played a great role in improving the accuracy of the cylinder. After repeated trials, Watt made great improvements to his original design and invented the compound steam engine in 1882. The previous single-type steam engine could only perform reciprocating motion, and had many similarities with Newcomb's machine. It was mainly used to lift water and had a limited range of use. A compound steam engine uses steam to do work, alternately pushing the piston from both sides, and uses an eccentric and a crank to change linear motion into rotational motion. He also invented a centrifugal speed regulator to automatically control the operating speed. After these improvements, Watt's steam engine not only improved its efficiency, but also became a versatile and versatile power machine that could power a variety of machines. The Soho factory was first equipped with a new steam engine, which was used to drive blowers, rolling mills and steam hammers. The new machine quickly spread and was used for grinding flour in flour mills, blasting air in ironworks, grinding malt in breweries, crushing flint in ceramic factories, crushing sugar cane in sugar refineries, etc. In 1785, the Sher Cotton Mill in Nottingham installed a steam engine, which has since become the main driving force of the textile industry.

The application of steam engines in land and water transportation led to the invention of steamboats and trains, which brought about a profound revolution in the transportation industry and ushered it into the age of steamships and railways.

Watt's invention was protected by patent, and Watt-Bolton Company became the only manufacturer supplying steam engines at that time, and steam engines became the company's main product. Between 1775 and 1880, the company produced 173 steam engines, 93 of which were used in the textile industry, 52 in the mining industry, and 28 in the metallurgical industry. Before the beginning of the 19th century, Britain had manufactured 1,200-1,330 steam engines, each with an average power of 15-16 horsepower. This new power machine soon spread to continental Europe, North America and other regions.

In the beginning, steam engine manufacturing was mainly based on handicraft production methods. The production speed was slow. The quality of the machine was determined by the skill level of the craftsmen. The reliability was poor and the cost was high, which was far from meeting the needs of society. In order to mass-produce steam engines, working machines for forging and metal cutting were needed, which promoted the development of the machine manufacturing industry.

Watt’s steam engine provided an efficient and reliable power machine for the modern factory industry that took the Industrial Revolution as an opportunity. It freed industry from dependence on natural forces such as water power and wind power, and made production no longer affected by climate change. The influence allows factories to be built in areas with better raw material supply, market and transportation conditions, thus also promoting the development of cities. Due to the proximity of relevant industrial departments, complete municipal facilities, and the interconnection of production, supply and marketing, the efficiency of industrial investment has been improved and the overall development of all walks of life has been promoted. Therefore, the invention of the steam engine was of epoch-making significance. It accelerated the completion of the Industrial Revolution in Britain and the process of industrial revolutions in other parts of the world, making an unprecedented leap in the development of productivity. Therefore, the 19th century was called the "Steam Engine Age."

In addition to inventing the steam engine, Watt also invented the hydrometer and the letter copying machine. He was the first to propose using propellers instead of paddle wheels to propel ships, and was the first to use "horsepower" as the unit for calculating power.

Watt's outstanding achievements have been highly praised and praised at home and abroad. He was admitted as a member of the famous Birmingham Crescent Society, was elected as a member of the Royal Society in 1785, and was awarded a doctorate in law from the University of Glasgow in 1806. In 1814, the French Academy of Sciences admitted him as a foreign member. After Watt's death in 1819, he was buried in Westminster Abbey. In order to commemorate him, later generations used his name "Watt" as the unit of measurement for work. Watt's name will forever be recorded in the history of world-famous inventors.