James Watt FRS FRSE ( / w ɒ t / ; 30 January 1736 (19 January 1736 OS ) – 25 August 1819) was a Scottish inventor, engineer, and chemist who improved Thomas Newcomen’s 1712 steam engine with his own design, the Watt steam engine, in 1776. This improvement was important for the Industrial Revolution in Great Britain and other parts of the world.

While working as an instrument maker at the University of Glasgow, Watt became interested in steam engine technology. At that time, engineers like John Smeaton knew that Newcomen’s engine had problems with efficiency. Watt realized that existing engines wasted energy by cooling and reheating the cylinder repeatedly. He added a new part, the separate condenser, which stopped this energy loss and greatly improved the power, efficiency, and cost-effectiveness of steam engines. Later, he adapted his engine to create rotary motion, which made it useful for more tasks than just pumping water.

Watt tried to sell his invention but faced financial challenges until he partnered with Matthew Boulton in 1775. The 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.

As Watt developed the idea of horsepower, the SI unit of power called the watt was named after him.

Biography

James Watt was born on January 19, 1736, in Greenock, Renfrewshire. He was the eldest of five children who survived infancy, 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, was well educated, and had a strong personality. His father was a shipbuilder, ship owner, and contractor. He also served as Greenock’s chief baillie in 1751. Part of the Watt family’s wealth came from his father’s trade in slaves and goods made by slaves. Watt’s parents were Presbyterians and strong supporters of the Covenanters movement. However, Watt later became a deist. His grandfather, Thomas Watt (1642–1734), was a teacher of mathematics, surveying, and navigation. He also served as a baillie to the Baron of Cartsburn.

Initially, Watt was taught at home by his mother. Later, he attended Greenock Grammar School, where he showed talent for mathematics but was not interested in Latin or Greek.

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

After leaving school, Watt worked in the workshops of his father’s businesses. He demonstrated skill in creating engineering models. When his father’s business failed, Watt left Greenock to find work in Glasgow as a maker of mathematical instruments.

At age 18, Watt’s mother died, and his father’s health worsened. Watt traveled to London and received a year of training as an instrument maker (1755–1756). He then returned to Scotland and settled in Glasgow, determined to start his own instrument-making business. At that time, he was young and had not completed a formal apprenticeship, so he lacked connections to become a journeyman instrument maker.

Watt’s opportunity came when he was asked to repair astronomical instruments sent from Jamaica to the University of Glasgow. These instruments had been left to the university by Alexander MacFarlane. Watt restored them and was paid for his work. The instruments were later placed in the Macfarlane Observatory. Soon after, three university professors offered Watt the chance to set up a small workshop on campus. This began in 1757. Two of the professors, physicist Joseph Black and economist Adam Smith, became Watt’s friends.

At first, Watt worked on repairing scientific instruments used by the university. He also 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 historians, like Samuel Smiles, say Watt had trouble starting his business in Glasgow because of opposition from the Trades House. However, others, like Harry Lumsden, disagree. Records from this time are incomplete, but it is clear that Watt faced challenges. Despite this, he was able to work and trade as a skilled metalworker, suggesting he met the requirements for membership in the Incorporation of Hammermen or avoided direct opposition.

In 1759, Watt partnered with John Craig, an architect and businessman, to make and sell products such as musical instruments and toys. This partnership lasted six years and employed up to 16 workers. Craig died in 1765. 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, the 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's lid rise when steam escaped. This tale is shared in many versions, sometimes showing Watt as a young boy or an older man, and sometimes mentioning his mother’s or aunt’s kettle. These differences suggest 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 use heat more efficiently, as scientists later understood. The story may have been written by Watt’s son, James Watt, Jr., who wanted to honor his father’s achievements. This tale is similar to the story of Isaac Newton and the falling apple, which also may not be completely accurate.

Although the kettle story is likely a myth, it has some truth. James Watt conducted many experiments to study heat and steam, and he used a kettle to create steam during these tests. In 1759, his friend John Robison told him about using steam to power machines. At the time, the Newcomen engine, used for over 50 years to pump water from mines, had not changed much. Watt began experimenting with steam, even though he had never seen a working engine. His early models failed, but he kept trying and studied everything he could about steam. He learned about latent heat, which is the energy released or absorbed during a process that keeps the temperature the same. This idea had been discovered earlier by his friend Joseph Black, but Watt did not know that.

In 1763, Watt was asked to repair a model Newcomen engine at a university. Even after fixing it, the engine barely worked. Through experiments, Watt found that most of the heat from the steam was wasted by heating the engine’s cylinder each time it operated. This happened because cold water was added later to condense the steam and lower its pressure. This process caused the engine to lose most of its energy instead of using it to do work.

In May 1765, while walking in Glasgow Green Park, Watt had an important idea: he would make steam condense in a separate chamber, not inside the engine’s cylinder. He also surrounded the cylinder with a "steam jacket" to keep it at the same temperature as the steam. This reduced energy loss, allowing more heat to be used for work. By the end of the year, Watt had built a working model of his engine.

Despite this success, building a full-scale engine was difficult and required money. Some support came from Joseph Black, but more help arrived from John Roebuck, who owned a famous iron factory. Roebuck and Watt formed a partnership, and Watt worked on his engine in a cottage near Roebuck’s home. Parts of this cottage and one of Watt’s projects still exist today.

The biggest challenge was making a tight seal between the piston and cylinder. Newcomen engines used water above the piston, so a water-tight seal was enough. Watt’s engine needed an air-tight seal, which was harder to achieve. Watt spent money trying to get a patent for his invention and had to take jobs as a surveyor and civil engineer for eight years to earn money.

Roebuck later went bankrupt, and Matthew Boulton, who owned a factory near 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. This partnership, Boulton and Watt, lasted 25 years and was very successful.

In 1776, the first working steam engines were used in businesses to power pumps. These engines only moved pump rods up and down, but they were successful. Watt installed many more engines in Cornwall to remove water from mines.

Boulton and Watt did not have their own factory until 1795, so they relied on others to make parts based on Watt’s designs. He supervised the setup of engines at first, then others in his company took over. Many workers helped build the engines, including William Murdoch and John Rennie.

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

Boulton encouraged Watt to change the engine’s motion from up-and-down to circular movement, which powered machines like grinders and weavers. A crank was the obvious solution, but a patent blocked them. They avoided the patent by using 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 used steam at higher pressures and designed compound engines that connected multiple engines. He received patents for these in 1781 and 1782. Other changes made the engines easier to build and install. One was the steam indicator, which showed pressure and volume in the cylinder, a secret Watt kept. Another was the parallel motion linkage, which helped move the piston smoothly. This was patented in 1784. A throttle valve and a centrifugal governor, patented in 1788, controlled the engine’s speed. Together, these changes made Watt’s engines 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 returned home but arrived too late—his wife had died, and their child was stillborn.

On July 29, 1776, Watt 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 ceased to exist in 1810. A Masonic Lodge in his hometown of Glasgow was named after him: Lodge James Watt, No. 1215.

Murdoch's contributions

William Murdoch began working for Boulton and Watt in 1777. At first, he worked in the pattern shop in Soho, but later he helped build engines in Cornwall. He became an important member of the company and contributed to its success through his work and inventions.

John Griffiths, who wrote a biography about Murdoch in 1992, said that James Watt did not support Murdoch’s experiments with high-pressure steam on a steam road locomotive. Watt believed that the boilers used at the time would be unsafe at higher pressures.

Watt received a patent for using the sun and planet gear with steam in 1781 and for a steam locomotive in 1784. Both inventions are strongly believed to have been created by Murdoch. Murdoch did not challenge the patents, and Boulton and Watt continued to use the sun and planet gear in their engines for many years, even after the patent for the crank ended in 1794. In 1810, Murdoch became a partner in the company and remained there until he retired at age 76, 20 years later.

Legacy

As one author states, Watt's improvements to the steam engine "changed it from a main source of power that wasn't very efficient into the important machine that drove the Industrial Revolution."

Honours

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

The unit of power called the watt is named after James Watt because of his work improving the steam engine. In 1889, the Second Congress of the British Association for the Advancement of Science officially 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, also known as "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 both men: "I sell here, sir, what all the world desires to have—POWER" (Boulton) and "I can think of nothing else but this machine" (Watt). This is the second time a Scottish person has been featured on a Bank of England note; the first was Adam Smith on a £20 note in 2007. The notes were released to the public on November 2, 2011.

In 2011, James Watt was one of seven people chosen to be the first inductees into the Scottish Engineering Hall of Fame.

Memorials

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

The garret room workshop that Watt used in his retirement was locked and untouched until 1853, when his biographer, J. P. Muirhead, first saw it. After that, it was sometimes visited but kept as a shrine. A plan to move the room to the Patent Office did not happen. In 1924, when the house was to be torn down, the room and its contents were given to the Science Museum, where it was recreated exactly as it was. It was displayed for many years but later enclosed when the gallery it was in closed. In March 2011, it was shown again as part of a new permanent Science Museum exhibit called "James Watt and our world."

A statue marks the approximate location of James Watt's birth in Greenock. Other memorials in Greenock include street names and the Watt Memorial Library, which was started in 1816 with Watt's donation of scientific books. His son later expanded it into the Watt Institution, which became the James Watt College. The library is now run by local authorities and holds local history and archives of Inverclyde. It also has a large seated statue in its entrance. Statues of Watt are also in George Square, Glasgow, and Princes Street, Edinburgh, as well as in Birmingham, where there is a monument called Moonstones and a school named after him.

The James Watt College now has campuses in Kilwinning (North Ayrshire), Finnart Street and The Waterfront in Greenock, and the 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. It was later renamed to honor George Heriot, a 16th-century financier, and James Watt. Many university and college buildings, especially those related to science and technology, are named after him. Soho House, Matthew Boulton's home, is now a museum honoring both men. The University of Glasgow's Faculty of Engineering is in the James Watt Building, which also houses the departments of Mechanical and Aerospace Engineering. The large painting "James Watt contemplating the steam engine," by James Eckford Lauder, is now in the National Gallery of Scotland.

A statue of James Watt is in Piccadilly Gardens, Manchester, and City Square, Leeds. A large statue of Watt, created by Francis Legatt Chantrey, was first placed in Westminster Abbey and later moved to St. Paul's Cathedral. The cenotaph has an inscription that says, 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 in the Hall of Heroes of the National Wallace Monument in Stirling, Scotland. A large statue of Watt, paired with one of George Stephenson, is on the main entrance of Budapest Keleti station. The French Navy submarine "Watt" was named after him.

Patents

James Watt was the only inventor listed on his six patents:

• Patent 913: A method to reduce steam use in steam engines – the separate condenser. The specification was accepted on 5 January 1769 and officially recorded on 29 April 1769. It was extended to June 1800 by an Act of Parliament in 1775.
• Patent 1,244: A new way to copy letters. The specification was accepted on 14 February 1780 and officially recorded on 31 May 1780.
• Patent 1,306: New methods to create continuous rotational motion – sun and planet. The specification was accepted on 25 October 1781 and officially recorded on 23 February 1782.
• Patent 1,321: Improvements to steam engines – expansive and double acting. The specification was accepted on 14 March 1782 and officially recorded on 4 July 1782.
• Patent 1,432: Improvements to steam engines – three bar motion and steam carriage. The specification was accepted on 28 April 1782 and officially recorded on 25 August 1782.
• Patent 1,485: Improved methods for building furnaces. The specification was accepted on 14 June 1785 and officially recorded on 9 July 1785.