Boulton and Watt’s partnership was hugely successful and lasted some 25 years

Watt was asked to repair a model Newcomen engine owned by Glasgow University in 1763. After much experimentation, he discovered that the majority of the energy was being wasted by repeatedly heating and cooling the engine cylinders. Watt discovered the solution while strolling through Glasgow's Green Park two years later: by creating a separate cylinder to cool the steam, you could keep the rest of the engine piston's temperature constant.

In 1776, Matthew Boulton, the owner of the Soho Manufactory works near Birmingham, saw the genius in Watt's design and purchased a share of his patent. With Boulton's help, Watt was able to perfect his engine at some of the world's finest ironworks. Watt then spent time in Cornwall installing pumping engines for copper and tin mines whose owners wanted to cut fuel costs. However, he was not a businessman.

Boulton and Watt's partnership was enormously successful and lasted for approximately 25 years, only to be continued by their sons Matthew Robinson Boulton and James Watt Jr-one of the interesting facts about James Watt.