Thomas Newcomen (1663-1729)

Thomas Newcomen was an ironmonger in Dartmouth, Devon in the late 17th century and some of his biggest customers were the mine owners in Cornwall, who had problems with flooding, especially as the mines were getting deeper. The usual way of removing the water by using horses to haul buckets up on a rope was slow and costly, so another method was needed.

Newcomen came up with a steam engine which had a vacuum inside a cylinder which pulled down a piston. He then used a lever to transfer the force to the pump shaft that went down the mine. It was the first practical engine to use a piston in a cylinder. Casting the cylinders and getting the pistons to fit was difficult because of the technology of the time so Newcomen deliberately made the piston smaller than the cylinder and sealed the gap with a ring of wet leather or rope.

His first working engine was installed at a coalmine in Staffordshire in 1712. It had a cylinder 21 inches in diameter and nearly eight feet long, and it could raise 10 gallons of water from a depth of 156 feet. It could do the same amount of work as five horses and could function 24 hours a day. Despite this it was not very efficient, and needed a lot of coal to heat the water which produced the steam, so it used in coalmines.

In 1714 Newcomen engines were expensive, costing about £1000 (the equivalent cost in 2002 would have been almost £100,000), but they were very successful and were manufactured for more than 100 years. One engine in Pentich was still operating 127 years after installation, and another was being used in Barnsley until 1934.

By the time of his death in 1729 there were at least 100 Newcomen engines working in Britain and across Europe.