James Watt FRS FRSE (born January 30, 1736 – died August 25, 1819) was a Scottish inventor, engineer, and chemist. He improved Thomas Newcomen’s steam engine, creating the Watt steam engine in 1776. This invention was important for the Industrial Revolution in Great Britain and around the world.

While working as an instrument maker at the University of Glasgow, Watt became interested in steam engines. At that time, engineers like John Smeaton knew that Newcomen’s engine was not working well and wanted to improve it. Watt noticed that existing engines wasted energy by cooling and reheating the engine’s cylinder repeatedly. He added a new part called a separate condenser, which saved energy and made steam engines work better, use less energy, and be cheaper to run. Later, he adapted his engine to create rotary motion, which allowed steam engines to be used for more tasks beyond pumping water.

Watt tried to sell his invention but had trouble making money until he partnered with Matthew Boulton in 1775. Their company, Boulton and Watt, became very successful, and Watt became wealthy. In his later years, he continued inventing, but nothing was as important as his work on the steam engine.

Watt also helped develop the idea of horsepower. The unit of power called the watt is named after him.

Biography

James Watt was born on January 19, 1736, in Greenock, Renfrewshire. He was the eldest of five children born to Agnes Muirhead (1703–1755) and James Watt (1698–1782). He was baptized on January 25, 1736, at Old West Kirk in Greenock. His mother came from an important family and was well-educated. His father was a shipwright, ship owner, and contractor who served as Greenock’s chief baillie in 1751. The Watt family’s wealth partly came from his father’s trade in slaves and goods made by slaves. Watt’s parents were Presbyterians and strong Covenanters, but he later became a deist. His grandfather, Thomas Watt (1642–1734), was a teacher of mathematics, surveying, and navigation and served as a baillie to the Baron of Cartsburn.

Initially, Watt was educated at home by his mother and later attended Greenock Grammar School. There, he showed talent for mathematics but was not interested in Latin or Greek.

Watt experienced long periods of illness as a child and suffered from frequent headaches throughout his life.

After leaving school, Watt worked in his father’s business workshops, showing skill in creating engineering models. When his father’s business failed, Watt left Greenock to work as a mathematical instrument maker in Glasgow.

At age 18, Watt’s mother died, and his father’s health worsened. Watt traveled to London, where he trained as an instrument maker for a year (1755–56). He then returned to Scotland and settled in Glasgow, determined to start his own instrument-making business. At the time, he was young and had not completed a formal apprenticeship, which limited his connections in the trade.

Watt’s opportunity came when the University of Glasgow received astronomical instruments from Jamaica, left by Alexander MacFarlane. These instruments needed expert repair, and Watt restored them, earning payment. The instruments were later placed in the Macfarlane Observatory. Three university professors then offered Watt a chance to set up a small workshop on campus. This began in 1757, and two professors, Joseph Black (a physicist and chemist) and Adam Smith (an economist), became Watt’s friends.

At first, Watt repaired and maintained scientific instruments used by the university, helped with demonstrations, and expanded the production of quadrants. He made and repaired brass reflecting quadrants, parallel rulers, scales, telescope parts, and barometers, among other items.

Some biographers, like Samuel Smiles, say Watt struggled to establish himself in Glasgow due to opposition from the Trades House. However, other historians, such as Harry Lumsden, disagree. Records from this time are incomplete, but it is clear Watt faced challenges. Nevertheless, he worked as a skilled metalworker, suggesting he met the requirements of the Incorporation of Hammermen or avoided direct opposition.

In 1759, Watt partnered with John Craig, an architect and businessman, to produce and sell musical instruments, toys, and other items. This partnership lasted six years and employed up to 16 workers. Craig died in 1765, and one employee, Alex Gardner, later took over the business, which continued into the 20th century.

In 1764, Watt married his cousin Margaret (Peggy) Miller. They had five children, two of whom lived to adulthood: James Jr. (1769–1848) and Margaret (1767–1796). His wife died in childbirth in 1773. In 1777, Watt married again, this time to Ann MacGregor, daughter of a Glasgow dye-maker. They had two children: Gregory (1777–1804), who became a geologist and mineralogist, and Janet (1779–1794). Ann died in 1832. Between 1777 and 1790, Watt lived in Regent Place, Birmingham.

Scientific studies and inventions

There is a well-known story that James Watt was inspired to invent the steam engine after seeing a kettle boil. The steam from the kettle pushed the lid upward, showing Watt how steam could be powerful. This story is told in many ways, sometimes with Watt as a young boy or an older man, and sometimes involving his mother’s or aunt’s kettle. This suggests the story might not be entirely true. However, Watt did not create the first steam engine. Instead, he improved the Newcomen engine by adding a separate condenser, which helped the engine use heat more efficiently, as scientists now understand. The story may have been created by Watt’s son, James Watt Jr., who wanted to honor his father’s achievements. This is similar to the story about Isaac Newton and the falling apple, which also may not be entirely accurate.

Although the story about the kettle might be a myth, it is based on real events. James Watt conducted many experiments to study heat and steam, and his diaries mention using a kettle to make steam during these tests. In 1759, a friend named John Robison told Watt about using steam to create motion. At the time, the Newcomen engine, used for over 50 years to pump water from mines, had not changed much since its invention. Watt began experimenting with steam, even though he had never seen a working steam engine. He tried building a model, but it did not work well. He kept experimenting and read everything he could about steam power. He learned about latent heat, which is the energy released or absorbed during a process that happens at a constant temperature. This idea had been discovered earlier by his friend Joseph Black, but Watt was unaware of it. At the time, the science of thermodynamics was not yet fully developed.

In 1763, Watt was asked to repair a Newcomen engine at a university. Even after fixing it, the engine barely worked. Through experiments, Watt found that most of the heat energy from the steam was wasted by heating the engine’s cylinder each time it operated. Cold water was then added to the cylinder to condense the steam, which caused the cylinder to heat and cool repeatedly, wasting energy instead of turning it into motion.

Watt’s key idea came in 1765 when he realized that steam should condense in a separate chamber instead of the main cylinder. He also surrounded the cylinder with a "steam jacket" to keep it at the same temperature as the steam. This reduced the energy lost to the cylinder, making more energy available for work. By the end of 1765, Watt had built a working model of his improved engine.

Creating a full-scale engine was challenging and required money. Some funding came from Joseph Black, but more support came from John Roebuck, who owned a famous ironworks. Watt worked on his designs in a cottage near Roebuck’s home. The cottage still stands today.

The biggest challenge was making the piston and cylinder fit tightly. Existing methods for making Newcomen engines were not suitable for Watt’s design, which needed a completely airtight seal. Watt spent much time and money trying to get a patent for his invention. Without enough resources, he worked as a surveyor and civil engineer for eight years.

Roebuck later went bankrupt, and Matthew Boulton, who owned a factory in Birmingham, bought the patent rights. Boulton helped Watt get a patent extension until 1800. Through Boulton, Watt gained access to skilled ironworkers, including John Wilkinson, who developed precise methods for making large cylinders. Watt and Boulton formed a successful partnership that lasted 25 years.

In 1776, the first working engines were used in businesses, mainly to power pumps in mines. These engines used back-and-forth motion to move pump rods. The design was successful, and Watt installed many more engines in Cornwall.

Boulton and Watt did not have their own factory until 1795, so parts of the engines were made by others using Watt’s designs. Watt supervised the setup of the engines at first, and later, workers from his company did this. Many people helped build the engines, including engineers like William Murdoch and John Rennie.

The engines were large. One early engine had a 50-inch-diameter cylinder and was 24 feet tall, requiring a special building to house it. Boulton and Watt charged customers a yearly fee equal to one-third of the coal savings compared to using a Newcomen engine.

Boulton encouraged Watt to use the engine’s motion to create circular movement for tasks like grinding and weaving. A crank was the obvious solution, but a patent blocked this. Watt and Boulton avoided the patent by inventing a "sun and planet gear" in 1781.

Over the next six years, Watt made many improvements. He created a double-acting engine, where steam pushed the piston on both sides. He also developed methods to use steam at high pressures and designed compound engines that connected multiple engines. These ideas were patented in 1781 and 1782. Other improvements included the steam indicator, which showed pressure and volume in the engine, and the parallel motion linkage, which helped create straight-line motion for pumps. These inventions made the engine up to five times more efficient than earlier models.

Family

On July 14, 1764, Watt married his cousin Margaret Miller, who died in 1773. They had two children: Margaret, born in 1767 and died in 1796, and James, born in 1769 and died in 1848. In 1791, their daughter married a man named James Miller. In September 1773, while Watt was working in the Scottish Highlands, he learned that his wife, who was pregnant with their third child, was very sick. He quickly went home but found that she had died, and their child was stillborn.

On July 29, 1776, he married Ann MacGregor, who died in 1832.

Freemasonry

He became a member of Scottish Freemasonry in the Glasgow Royal Arch Lodge, No. 77, in 1763. The Lodge no longer existed by 1810. A Masonic Lodge in his hometown of Glasgow was named after him—Lodge James Watt, No. 1215.

Murdoch's contributions

William Murdoch joined the company Boulton and Watt in 1777. He first worked in a workshop in Soho, but later helped build engines in Cornwall. He became a key member of the company and contributed to its success through his work and by creating several important inventions.

John Griffiths, who wrote a biography about Murdoch in 1992, said that James Watt discouraged Murdoch from using high-pressure steam in his experiments with a steam-powered road vehicle. Watt believed that the boilers used at the time would be unsafe if they operated at higher pressures.

James Watt received a patent for using a sun and planet gear with steam in 1781 and for a steam locomotive in 1784. Some evidence suggests that Murdoch may have invented these designs. Murdoch did not challenge the patents, and the company Boulton and Watt continued to use the sun and planet gear in their engines for many years, even after the patent for the crank expired in 1794. In 1810, Murdoch became a partner in the company and remained in that role until he retired 20 years later at the age of 76.

Legacy

As one author explains, Watt's improvements to the steam engine changed it from a machine that was not very efficient into the main machine that powered the Industrial Revolution.

Honours

James Watt received many honors during his lifetime. In 1784, he became a member of the Royal Society of Edinburgh. In 1787, he was elected to the Batavian Society for Experimental Philosophy in Rotterdam, Netherlands. In 1789, he joined the Smeatonian Society of Civil Engineers, an elite group. In 1806, the University of Glasgow gave him an honorary Doctor of Laws degree. The French Academy elected him a Corresponding Member, and in 1814, he became a Foreign Associate.

The watt unit is named after James Watt because of his work on the steam engine. In 1889, the Second Congress of the British Association for the Advancement of Science adopted the watt as a unit of power. In 1960, the 11th General Conference on Weights and Measures included the watt in the International System of Units (SI).

On May 29, 2009, the Bank of England announced that James Watt and Matthew Boulton would appear on a new £50 note. This note is the first to show two people side by side. It includes images of Watt’s steam engine and Boulton’s Soho Manufactory. The note also has quotes from each man: “I sell here, sir, what all the world desires to have—POWER” (Boulton) and “I can think of nothing else but this machine” (Watt). Watt is the second Scot to appear on a Bank of England note, following Adam Smith on the 2007 £20 note. The notes were released on November 2, 2011.

In 2011, James Watt was one of seven people chosen for the Scottish Engineering Hall of Fame.

Memorials

James Watt was buried in the grounds of St. Mary's Church in Handsworth, Birmingham. Later, when the church expanded, part of the building was constructed over his grave, so his tomb is now inside the church.

The small workshop room where Watt worked during his retirement remained locked and untouched until 1853, when his biographer, J. P. Muirhead, first visited it. After that, the room was occasionally visited but kept as it was, like a shrine. A plan to move the room to the Patent Office was not carried out. When the house where the workshop was located was scheduled to be torn down in 1924, the room and everything inside were donated to the Science Museum. There, the room was recreated exactly as it was and displayed for many years. Later, when the museum gallery closed, the room was walled off. However, in March 2011, the workshop was put on public display again as part of a new permanent exhibition at the Science Museum titled "James Watt and our world."

The place where James Watt was born in Greenock is marked by a statue. Other memorials in Greenock include street names and the Watt Memorial Library, which began in 1816 with books donated by Watt. His son later helped develop the library as part of the Watt Institution, which eventually became James Watt College. The library is now managed by the local government and holds local history collections and archives from Inverclyde. A large seated statue of Watt is displayed in the entrance area of the library. Statues of Watt also stand in George Square, Glasgow, and Princes Street, Edinburgh, as well as in Birmingham, where a monument called the Moonstones and a school named after him honor his memory.

James Watt College has grown to include campuses in Kilwinning (North Ayrshire), Finnart Street, The Waterfront in Greenock, and a sports campus in Largs. Heriot-Watt University near Edinburgh was once the School of Arts of Edinburgh, founded in 1821 as the world's first Mechanics Institute. To honor George Heriot, a 16th-century financier, and James Watt, the university's name was changed to Heriot-Watt University after receiving a royal charter. Many university and college buildings, especially those related to science and technology, are named after Watt. Soho House, the home of Matthew Boulton, is now a museum that honors the work of both men. The University of Glasgow's Faculty of Engineering is based in the James Watt Building, which also houses departments of Mechanical Engineering and Aerospace Engineering. A large painting titled "James Watt contemplating the steam engine," created by James Eckford Lauder, is now owned by the National Gallery of Scotland.

Statues of James Watt can also be found in Piccadilly Gardens, Manchester, and City Square, Leeds. A large statue of Watt, created by Francis Legatt Chantrey, was originally placed in Westminster Abbey and later moved to St. Paul's Cathedral. An inscription on the cenotaph reads, in part, "JAMES WATT … ENLARGED THE RESOURCES OF HIS COUNTRY, INCREASED THE POWER OF MAN, AND ROSE TO AN EMINENT PLACE AMONG THE MOST ILLUSTRIOUS FOLLOWERS OF SCIENCE AND THE REAL BENEFACTORS OF THE WORLD."

A bust of Watt is displayed in the Hall of Heroes at the National Wallace Monument in Stirling, Scotland. A large statue of Watt, placed alongside one of George Stephenson, is featured on the main entrance of Budapest Keleti Station. The French Navy submarine named "Watt" was also named in his honor.

Patents

Watt was the only inventor named in his six patents:

• Patent 913: A way to reduce steam use in steam engines – the separate condenser. The details were approved on January 5, 1769, recorded on April 29, 1769, and continued until June 1800 through a law passed in 1775.
• Patent 1,244: A new method to copy letters. The details were approved on February 14, 1780, and recorded on May 31, 1780.
• Patent 1,306: New ways to create continuous rotational motion – sun and planet. The details were approved on October 25, 1781, and recorded on February 23, 1782.
• Patent 1,321: New improvements to steam engines – expansive and double acting. The details were approved on March 14, 1782, and recorded on July 4, 1782.
• Patent 1,432: New improvements to steam engines – three bar motion and steam carriage. The details were approved on April 28, 1782, and recorded on August 25, 1782.
• Patent 1,485: Newly improved methods for building furnaces. The details were approved on June 14, 1785, and recorded on July 9, 1785.