The 200-ton Trinity reputedly featured a large copper boiler powering a pair of paddle wheels - but nothing more was heard of it, and the dream of steam power slumbered on for nearly another century.
Edward Somerset, son of the first Marquis of Worcester, finally put steam on the map just before the start of the English Civil War in 1641. Although many historians refuse to recognise the fact, there is compelling evidence that Somerset had a steam pump up and running before hostilities broke out.He installed it in the keep of the family seat, Raglan Castle in South Wales, and the story goes that it was used as a 'weapon of mass distraction' to frighten Parliamentary forces.
Apparently, when Roundhead forces arrived at the castle to demand its surrender, the order was given to start the steam pump. As it hissed and roared into life, someone shouted "The Lions have got loose," and the Parliamentarians, knowing the marquis kept a menagerie at the castle, fled for their lives.
Sadly, the Worcesters' huge fortune was squandered supporting an ungrateful Royal Family, Somerset - by now the second Marquis - fled to the continent at the end of the war, and when he returned he was too old and impoverished to turn his idea into a saleable proposition.
Somerset's pump used steam in two ways. First, it was allowed into a sealed chamber which was then cooled. This created a vacuum, which sucked open a valve connecting to a pipe with its end in the water which was to be pumped.Water rushed up the pipe into the empty chamber and, pressure then being equalised, the valve closed of its own accord. At this point, more steam was admitted and the water in the chamber was forced upwards through another valve into the exit pipe, to a height of perhaps 40 feet.
Somerset never made a penny out of his machine, but the idea was taken up more than half a century later by a Devon man called Thomas Savery, who probably read about it in Somerset's 1655 book. The book's full title is too long to repeat, but it is known universally as The Century, and Savery
He called his invention The Miner's Friend, but in reality, it was no such thing. He touted it as being an ideal way of draining mines, but it was dangerous and ineffective at the depths at which it would have had to work, and there is no known record of it ever having been used in a pit.
It was another Devon man, Thomas Newcomen, who made the first practical engine using the power of steam, and his design was elegantly simple. He connected a copper boiler to a cylinder, in which a piston was free to move up and down.
Steam expanding from the boiling water passed into the base of the cylinder, allowing the counter-balanced piston to rise. As the piston reached the top of its travel, it uncovered a vent through which cold water was sprayed into the cylinder.