He was born in January 1736, the son of an architect and shipbuilder. It is said that when James Watt was a child, he noticed that the steam in a boiling kettle repeatedly lifted its lid. Perhaps it was this memory that inspired him to improve the steam engine in later years. Certainly throughout his childhood he showed a great interest in machines and had a keen mathematical brain so that, by the age of 19 he was already at the University of Glasgow where he was employed as a scientific instruments maker. In 1763, James Watt was asked at work one day to repair a model of a Newcomen engine. This event marked a vital turning point in history as Watt soon realised while completing the task that he could make the engine much more efficient, a realisation that was to have vital impact on the industrial revolution.
Steam power had been discovered by a man called Thomas Savey in 1698, but had only been put to any kind of use by Thomas Newcomen in 1720. Newcomen had designed an engine that used steam from the boiler that entered the cylinder, causing the piston to rise. When it reached the top, cold water was fed into the chamber, making the hot steam condense, thus creating a partial vacuum that pushed the piston back down the cylinder again. Here is a picture of what the finished design looked like.
The Newcomen engines were very successful, many coal mines and Cornish tin mines used them to help pump out the water from the mines and one of the newest industries, the iron works, found this invention useful to keep there main source of power consistent throughout the year. This was to keep the water wheels working because in the summer the water channels became dry, Newcomen's engine meant that water could be pumped into these channels all year round. As well as the advantages of this machine there were many problems. The engine needed a lot of work throughout the year just to keep it going and it was expensive to run because it needed a lot of coal as fuel.
The trouble with Newcomen's engine was that it's cylinder had to be cooled between each stroke to condense the steam and this made the engine efficient. Watt determined the properties of steam, especially the relation of its density to its temperature and pressure and decided that it would make the design much more economical and faster at working if the condenser and the cylinder were separated. Then the condenser could be cool all the time, and the cylinder could be hot all the time. This would prevent enormous losses of steam in the cylinder and enhance the vacuum conditions and save fuel.
Although Watt completed his invention in 1765, numerous problems meant that it could not go into production. Even more than Newcomen, Watt needed accurately made cylinders. He also needed accurate small parts for the valve-box. James Watt teamed up with John Roebuck in the early 1770s, at the Carron Ironworks but their first full scale engine failed because the quality of the workmanship could not match the demands put on the machine. Their partnership failed in 1773 when Roebuck was declared bankrupt.
However Watt was introduced to a British manufacturer who owned the Soho Engineering Works at Birmingham called Matthew Boulton. He realised the great potential of Watt's engine but also knew that there was still a great deal of work to be done. Matthew Boulton took over John Roebuck's interests and the new partnership of Boulton and Watt,...