In the meantime, working practices and developments across the Atlantic were free from the obligation to respect Watt’s patents. High wages, specialisation in work and openness to change all made America ripe for technological innovation. In 1787 John Fitch used an atmospheric steam engine lying on its side to power a set of twelve oars on a riverboat. Powering a boat by steam was a fertile line of development, since it could carry the weight of an engine much more easily than a road carriage. Fitch unsuccessfully tried to get a legal monopoly over the use of steam for transport and the next American steam pioneer, Oliver Evans, took its application one step further. Evans understood that ‘the more the steam is confined . . . the greater will be the power obtained by the fuel. For every addition of 30 degrees of heat to the water doubles the power, doubling the heat of the water increases the power [of the engine] 100 times.’ In other words, a vastly more powerful engine could run on only a small increase in fuel.3
Evans came up with the idea of placing the furnace inside the boiler, which had remained more or less unchanged since Newcomen’s time. Being able to produce the same power with a smaller engine opened up the possibility of putting the engine on a wheeled carriage, but Evans found little enthusiasm for this project, as roads were poor and tramways not as highly developed as in Britain. Evans resorted to making stationary engines for mills but his work on high-pressure steam may have had an intriguing legacy. By his own account, written in 1805, ‘In 1794–95, I sent drawings, specifications, and explanations, to England to be shown to the steam engineers there, to induce them to put the principles into practice.’4 These were taken to England by Joseph Stacey Simpson, who died there, and we don’t know the fate of Evans’s papers. It is possible that they were seen by British steam engineers, but there is no firm evidence. However, strong steam and its use for transport was being openly discussed in Britain well before 1794 and was released into the world, almost as soon as Watt’s patent expired, by the intoxicating figure of Richard Trevithick.
Trevithick was born in 1771 in Carn Brea in Illogan parish in the heart of the Cornish mining industry. His father, who clashed so memorably with James Watt (see here), was the mine captain – a combination of manager and chief engineer – at Wheal Treasury mine. While receiving some formal education at Camborne School, Richard received most of his learning in and around mines. By 1786, when Trevithick was fifteen years old, there were twenty-one Boulton & Watt engines in Cornwall and he learned every detail of how they worked.
Trevithick was in some ways the opposite of James Watt. A huge man of six feet and two inches – he became known as ‘the Cornish giant’ – he was confident, outgoing and wildly enthusiastic, full of physical and mental energy and prepared to throw himself into every project. He took his first job at the age of nineteen, at East Stray Park mine near Camborne, probably working for William Bull. Bull had been hired by Cornish mine-owners to build engines different from Watt’s, in order to get round the inventor’s patent. In 1793 Boulton & Watt sued Bull over breach of their patent and Trevithick was implicated through his work with the Cornish engineer. Trevithick became a Cornish celebrity when he appeared as an expert witness in Jonathan Hornblower’s defence against Boulton & Watt, which further exacerbated Watt’s hostility to Trevithick’s work.
During the late 1780s and 1790s, with engineers eager to make improvements to steam engines, some were clearly pursuing the idea of making an engine driven by high-pressure steam. In his discouragement of his employee William Murdoch, Watt wrote to Boulton: ‘I wish William could be brought to do as we do, to mind the business in hand, and let such as Symington and Sadler throw away their time and money chasing shadows.’5 William Symington had patented an improved engine in 1787, using strong steam to push the condensate out of the condenser, which then powered a second piston. He built engines for mines and mills but is best known for installing steam engines on boats, leading to the world’s first successful steamboat journey by the Charlotte Dundas in January 1803. James Sadler was a famous balloonist who developed the ‘table-top steam engine’, and it is thought that Arthur Woolf, a native Cornishman who later patented the compound steam engine, was working on high-pressure steam in London in the 1790s. The clear implication of Watt’s comments is that he thought these innovators were simply following the wrong tracks. What is unclear is how much Richard Trevithick learned from them (and his one-time neighbour William Murdoch) and how much he figured out for himself.
Like Watt, Trevithick was not a wealthy man and in 1796 he joined forces with his cousin Andrew Vivian, who invested money in his ideas. He also met Davies Gilbert, MP for Penzance and then Bodmin, and an eminent Cornish scientist who later (1827–30) succeeded Humphry Davy as president of the Royal Society. It was Gilbert who answered one of Trevithick’s most pressing questions. Trevithick saw that if an engine was powered by the force of steam pushing a piston, then there would be no need for a separate condenser, and the waste steam could be pushed out of the cylinder by the piston on the return stroke. But he needed to know whether all the pressure in the cylinder would be lost in each cycle, or whether some would be retained. Gilbert believed that the pressure lost would be the same as the outside atmospheric pressure, and that any additional pressure would be retained inside the hot cylinder. This meant that the steam could be pushed out straight into the atmosphere without robbing the engine of all its power at each stroke.
By 1796 Trevithick had built a model of a new steam engine, usable both as a stationary machine and for powering a locomotive. A boiler produced steam which was then directed under pressure into a cylinder; the pressure pushed out a piston which was connected directly to a crank and thereby used to drive a shaft. The rotation of the shaft, with a flywheel attached, pushed the cylinder back down at the opposite end of the cycle, and the steam was expelled through an opened valve. This engine was far simpler than the Newcomen or Watt engines: there was no beam, no condenser and no apparatus for feeding the steam into a separate condenser. Not only that: much more power could be generated from the same size of piston thereby allowing the cylinders and pistons to be made smaller. In addition, with no need for condensation and because of the simple cycle of input and exhaust the engine could be run much faster than a Watt engine. Moreover, Trevithick’s design housed the engine cylinder within the boiler, so saving space and keeping the outside of the cylinder continually heated. The new engine was probably first used at full working scale in 1800 for turning the shaft of a winding wheel at the Wheal Hope mine at Dolcoath, Camborne. But Trevithick knew that the new engine, with its small size and lightness, could be used to drive a vehicle.
Trevithick’s Puffing Devil: The single cylinder drove a piston rod connected to a flywheel, which was also connected to one set of road wheels. The vertical cylinder is located inside the large boiler.
We need to understand what a huge step this was: until this moment humanity had been able to travel only at the speed of a fast horse. Trevithick was about to make the means of propulsion part of the carriage itself and thereby break down any technical barrier to speed. But there was one major concern: the engine would power the wheels of the carriage, but would powered wheels simply slip on the road surface while the engine turned them round, leaving the carriage standing still? To find out, Trevithick and Vivian hired a one-horse chaise and moved it along the roads near Camborne by laboriously turning the wheels by hand.
The stage was set, but no one outside a small circle seemed aware of what was about to happen. Then, on Christmas Eve 1801, Richard Trevithick and a group of friends appeared on Camborne Hill propelled along on board a wooden-framed carriage driven by a single-cylinder engine with a tall chimney. The Puffing Devil made its first journey from Camborne Hill to nearby Beacon Hill, travelling around one kilometre. As one of the passengers recalled: ‘Captain Dick got up steam, out in the high-road, just outside the shop at the Weath. When we get see’d that Captain Dick was agoing to turn on steam, we jumped up as many as could, maybe seven
or eight of us. ’Twas a stiffish hil going from the Weight up to Camborne Beacon, but she went off like a little bird.’6
The length of journey was limited by the need for a continual water supply; nevertheless the maiden trip was a success. The vehicle itself came to grief just three days later when Andrew Vivian lost control of the steering handle, and the Puffing Devil was stranded. Davies Gilbert described what happened next: ‘The carriage was forced under some shelter, and the Parties adjourned to the Hotel, & comforted their Hearts with a Roast Goose and proper drinks, when, forgetfull of the Engine, its Water boiled away, the Iron became red hot, and nothing that was combustible remained of the Engine or the house.’7
The end of the Puffing Devil marked the beginning of a transport revolution. Freed from the constraints of other inventors’ patents, on 24 March 1802 Trevithick and Vivian jointly took out a patent ‘as for improving the construction of steam-engines, and the application thereof for drawing carriages on rails, turnpike roads, and other purposes’.
Trevithick adapted his engines to work more smoothly by adding another cylinder, with the piston rods of the two cylinders working a quarter-turn apart. The firebox and the cylinder were both located within the boiler, which was made cylindrical to bear high pressure. The early locomotive engine could work with steam at a pressure of sixty to eighty pounds per square inch (atmospheric pressure is around 15 psi), and a second safety valve was fitted.
In 1803 Trevithick decided to show the world his steam carriage and a vehicle was shipped from Plymouth to London. The engine, about the size of an orchestra drum, was fitted between the rear wheels of a phaeton carriage. Trials were carried out at Lord’s cricket ground before the steam carriage was taken down New Road and Gray’s Inn Lane. Despite this spectacular demonstration there were setbacks which caused Trevithick’s backers to doubt the engine’s potential. That same year a high-pressure Trevithick engine used to pump water at a corn mill in Greenwich exploded, killing four men. The accident was due to careless operation, as Trevithick wrote to Davies Gilbert:
It appears the boy that had the care of the engine was gon to catch eales in the foundation of the building, and left the care of it to one of the Labourers; this labourer saw the engine working much faster than usual, stop’d it without takeing off a spanner which fastned down the steam lever, and a short time after being Idle it burst. It killed 3 on the spot and one other is since dead of his wounds. The boy returned at the instant and was going to take off the trig from the valve. He was hurt, but is now on recovery; he had left the engine about an hour . . . I believe that Mr B. [Boulton] & Wat is abt to do mee every engurey in their power for they have don their outemost to report the explosion in the newspapers and private letters very different to what it really is.8
The comment about Boulton & Watt shows the bitterness that still lingered between these competitors. In response to the accident Trevithick introduced further safety measures, including duplicate safety valves; a pressure gauge filled with mercury, which blew out under excess pressure allowing the steam to escape; and a lead plug that would melt once the temperature reached dangerous levels.
Fortunately help was also about to arrive from an unexpected quarter. Samuel Homfray, the owner of the Pen-y-darren ironworks near Merthyr Tydfil, and an early believer in steam locomotion, came to an arrangement with Trevithick, taking a share of the patents in return for a financial investment. Just as significantly, Homfray made a bet of 500 guineas with his fellow ironmaster Anthony Hill that a steam locomotive could pull a full ten tons of iron along the ten miles of tramway from Pen-y-darren to the Merthyr–Cardiff canal at Abercynon. He was relying on Trevithick to deliver.
This was another hugely significant moment. Like other steam enthusiasts, Trevithick had envisioned an age of steam-powered vehicles running on roads. But Homfray’s business, in common with many ironworks and collieries, depended on shifting bulk freight along tramways, using horses to pull specially built wagons. He wanted Trevithick to build not a steam carriage, but a steam-powered rail locomotive.
Trevithick set to work immediately and by February 1804 had built this new steam-driven vehicle. The engine used a horizontal cylinder with divided or forked connecting rods from the piston to allow room for a crank to rotate within the fork. The single cylinder engine was eight inches in diameter with an eight-foot flywheel. The exhaust steam was run up the chimney (the same chimney as the fire) thus creating a draft that made the fire burn better. On 13 February the engine ran for ten miles pulling the equivalent of ten tons of iron, at five miles an hour without stopping for water. Then two weeks later, on 28 February, came the decisive moment: the two ironmasters witnessed a repeat performance and Homfray won his bet. Trevithick described the historic journey in a letter to Davies Gilbert the next day: ‘Yesterday we proceeded on our journey with the engine; we carry’d ten tons of Iron, five waggons, and 70 Men riding on them the whole of the journey. It’s above nine miles which we performed in 4 hours & 5 mins, but we had to cut down some trees and remove some large rocks out of the road. The engine, while working, went nearly 5 miles pr hour; there was no water put into the boiler from the time we started until we arriv’d.’9
Just four years after the expiration of Watt’s patent, Trevithick was capable of producing engines lighter, smaller, more powerful and of wider application than those built by Watt over the previous twenty-five years. And crucially, the reduction in weight and increase in power allowed the engines to be carried on the vehicles that they themselves powered. The Pen-y-darren locomotive had most of the essential features of steam locomotives that would transform the world over the next 150 years.
Pen-y-darren locomotive: The world’s first steam locomotive used a single cylinder to drive a flywheel which transmitted power, via an intermediate cogged wheel, to the wheels on the track.
While the Pen-y-darren engine would not immediately convert the world, it made significant inroads into the area that was to be the heartland of railway engineering – the north-east of England. A Trevithick locomotive was built for a colliery in Newcastle in 1805 and a young colliery engineer named George Stephenson began making locomotives nearby in the following decade. Trevithick’s own final attempt to launch the locomotive on the world came with an elliptical railway installed in Euston Square in London. Advertised as ‘Catch Me Who Can’, the vehicle ran for two months, July and August 1808, to crowds of spectators who paid one shilling to travel at 12 mph.
Trevithick also turned his attention to building high-pressure static steam engines. He designed engines for boring, milling, rolling, crushing, stamping, blowing as well as pumping water; he put a high-pressure engine on a barge to drive paddle wheels and built a steam-powered dredger.
Further innovations followed in 1812. Trevithick greatly improved the ‘Cornish boiler’ in which the steam was heated by tubes carrying hot exhaust through the boiler – ‘Others have put the boiler in the fire,’ Trevithick declared, ‘I have put the fire in the boiler.’ His ‘Cornish engine’, which combined high-pressure steam with a condensing process, would be used all over the world. That same year Trevithick built a high-pressure rotative engine to drive a threshing machine – it worked for seventy years and is preserved in the Science Museum in London – and went on to make a rotary-powered cultivator with a four-wheeled chassis that could be towed across a field while a series of blades cut up the earth.
Perhaps his final great invention of this extraordinary period was the 1815 steam turbine and propeller. Trevithick called his device a recoil engine; it worked on the principle of Hero’s aeolipyle, being powered by pushing steam out of a series of vents like a huge Catherine wheel. The central driveshaft was then connected to a screw-like device, which was an embryonic ship’s propeller.
Steam was only one of this extraordinary man’s interests. Trevithick developed the use of iron tanks for storage on ships and built a small works at Limehouse to produce them. A patent of 1809 specified a huge range of inventions for u
se on ships, ranging from telescopic masts and bowsprits to diagonally ribbed hulls, iron floating docks and iron buoys. But Trevithick was less successful at managing his financial affairs; in 1808 he entered into a doomed partnership with Robert Dickinson; both were made bankrupt in 1811, though Trevithick managed to clear his outstanding debts within three years.
Trevithick’s energetic life became even more colourful when in 1816 he set sail for South America with the hope of making his fortune in mining. He began work as an engineer in Lima but was soon caught up in the wars of independence that were sweeping the continent. Joining the army of Simón Bolívar he promptly designed a new type of carbine (a shortened rifle) made of brass, with the stock and barrel forged in one piece. The conflicts scuppered his chances of realising his mining ambitions so he went north, becoming one of the first group of Europeans to cross the isthmus of Nicaragua. When he reached Cartagena on the Caribbean coast of Colombia in 1827 he was penniless, and lucky to meet Robert Stephenson, son of George, who paid for his journey back to England.
In London George Stephenson, then a successful locomotive engineer, petitioned Parliament to give the penniless inventor a pension in recognition of his work; but this request was refused. Trevithick’s last projects included building a huge ball-and-chain pump for dredging canals in Holland, and a design for a cast-iron tower 1,000 feet high to commemorate the Reform Bill of 1832; neither came to fruition. Richard Trevithick died aged sixty-two in 1833 in Dartford, Kent.
Iron, Steam & Money Page 14
