By the age of nineteen, Cornishman Richard Trevitbick (1771-1833) worked for the the Cornish mining industry as a consultant engineer. The mine owners were attempting to skirt around the patents owned by James Watt, inventor of the steam engine, because the royalties were costing them a fortune.
William Murdoch had developed a model steam carriage, starting in 1784, and demonstrated it to Trevithick in 1794. Trevithick thus knew that recent improvements in the manufacturing of boilers meant that they could now cope with much higher steam pressures than before. Using steam at a higher pressure, Trevithick could eliminate the need for a separate condenser, which was integral to the patents held by Watt, as well as peripherals such as the air pump. Further, Watt's low-pressure engines required large buildings to house them. By using high-pressure steam in his experimental engines, Trevithick was able to make them smaller, lighter, and more manageable.
Trevithick constructed high-pressure working models of both stationary and locomotive engines that were so successful that in 1799 he built a full-scale, high-pressure engine for hoisting ore. The "used" steam was vented out through a chimney into the atmosphere, bypassing Watt's patents. Later, he built a full-size locomotive that he called Puffing Devil. On December 24, 1801, this bizarre-looking machine successfully carried several passengers on a journey up Camborne Hill in Cornwall. Despite objections from Watt and others about the dangers of high- pressure steam, Trevithick's work ushered in a new era of mechanical power and transport.
