See [[Steam engine]], [[Steam power during the Industrial Revolution]].  

'''Steam power''' developed slowly over a period of several hundred years, progressing through expensive and fairly limited devices in the early 1600s, to useful pumps for [[mining]] in 1700, and then to Watt's improved designs in the late 1700s. It is these later designs, introduced just when the need for practical power was growing due to the [[Industrial Revolution]], that truly made steam power commonplace.

====== Early examples ======

  *~130 BC: [[Hero of Alexandria]] describes the [[aeolipile]], as an example of the power of heated air or water. The device consists of a rotating ball spun by steam jets; it produced little power and had no practical application, but is nevertheless the first known device moved by steam pressure. He also describes a way transferring water from one vessel to another using pressure, filling a bucket the weight of which worked tackle to open temple doors, closed again by a deadweight once the water in the bucket had been drawn out by a vacuum caused by cooling of the initial vessel.
  *[[1551]]: [[Taqi al-Din]] describes a [[steam turbine]]-like device for rotating a spit.
  *[[1601]]: [[Giovanni Battista della Porta]] performs experiments on using steam to create pressure or a vacuum.
  *[[1615]]: [[Salomon de Caus]], who had been an engineer and architect under [[Louis XIII of France|Louis XIII]], publishes a book showing a device similar to that of Porta.
  *[[1629]]: [[Giovanni Branca]] suggests using a steam [[turbine]] device similar to that described by Taqi al-Din but intended to be used to power a series of pestles working in mortars.
  *[[1630]]: [[David Ramsey]] is granted a patent for various steam applications, although no description is given and the patent also covers a number of unrelated inventions. He refers to a "fire engine", and this term is used for many years.

======Towards a workable steam engine======
  *[[1663]]: [[Edward Somerset, 2nd Marquis of Worcester]], publishes a selection of his inventions. One is a new sort of steam pump, essentially two devices like de Caus', but attached to a single boiler. A key invention is the addition of cooling around the containers to force the steam to condense. This produces a partial vacuum inside the chambers, which is used to draw a volume of water into the containers through a pipe, thus forming a pump. He builds one of very large size into the side of [[Raglan Castle]], apparently the first "industrial scale" steam engine. He has plans to build them for mining, but dies before he can set up his company.
  *[[1698]]: [[Thomas Savery]] introduces a steam pump he calls the Miner's Friend. it is almost certainly a direct copy of Somerset's design. One key improvement is added later, replacing the cold water flow on the outside of the cylinder with a spray directly inside it. A small number of his pumps are built, mostly experimental in nature, but like any system based on suction to lift the water, they have a maximum height of 32 feet (and typically much less). In order to be practical, his design can also use the pressure of additional steam to force the water out the top of the cylinder, allowing the pumps to be "stacked", but many mine owners were afraid of the risk of explosion and avoided this option. (Savery engines were re-introduced in the 1780s to recirculate water to water wheels driving textile mills, especially in periods of drought).
  *c.[[1705]]: [[Thomas Newcomen]] develops the [[atmospheric engine]], which, unlike the Savery pump, employs a piston in a cylinder; the vacuum pulling the piston down to the bottom of the cylinder when water is injected into it. The engine enabled a great increase in pumping height and the draining of deeper mines than hitherto possible. Savery holds a patent covering all imagined uses of steam power so Newcomen and his partner [[John Calley]] persuade Savery to join forces with them to exploit their invention until the expiration of the patent in 1733.
  *[[1707]]: [[Denis Papin]] publishes a study on steam power, including a number of ideas. One uses a Savery-like engine to lift water onto a [[water wheel]] for rotary power. The study also proposes replacing the water of a Savery engine with a piston, which is pulled on by the vacuum in a cylinder after steam inside is condensed, but he was unable to build the device.
  *1718: Desaguliers introduces an improved version of the Savery engine, which includes safety valves and a two-way valve that operated both the steam and cold water (as opposed to two separate valves).  It is not commercially employed.
  *[[1720]]: ­Leupold designs an engine based on expansion, which he attributes to Papin, in which two cylinders alternately receive steam and then vent to the atmosphere. Although likely a useful design, it appears none were built.

======The Newcomen Engine: Steam power in practice======
  *[[1712]]: [[Newcomens dampmaskine|Newcomen]] installs his first commercial engine <ref>Hulse David K (1999): "The early development of the steam engine"; TEE Publishing, Leamington Spa, UK, ISBN, 85761 107 1</ref>.
  *[[1713]]: [[Humphrey Potter]], a boy charged with operating a Newcomen engine, installs a simple system to automatically open and close the operating valves. The engine can now be run at 15 strokes a minute with little work other than firing the boiler.
  *[[1718]]: [[Henry Beighton]] introduces an improved and much more reliable version of Potter's operating system.
  *[[1733]] Newcomen's patent expires. By this time about 100 Newcomen engines have been built. Over the next 50 years engines are installed in collieries and metal mines all over England, notably in [[Cornwall]], and are also used for municipal water supply and pumping water over water wheels, especially in ironworks.
  *[[1769]]: [[John Smeaton]] experiments with Newcomen engines, and also starts building improved engines with much longer piston stroke than previous practice. Later engines, which marked probably the high point of Newcomen engine design, deliver up to 80 horsepower (around 60 kW).
  *[[1775]]: By this date about 600 Newcomen engines erected in the UK.
  *[[1779]]: The crank first applied by [[James Pickard]] to a Newcomen engine, producing rotary motion.  Pickard patents this the following year, but the patent is unenforcable.
  *[[1780]]-[[1800]]: [[Newcomens dampmaskine|Newcomen]] engines continue to be built in large numbers (about a thousand between 1775 and 1800), especially for mines but increasingly in mills and factories.  Many have Watt condensers added after the patent expires (see below).  Several dozen improved [[Savery]] engines are also built.

======Watt's engine======
  *[[1765]]: [[James Watt]] hits on the idea of the separate condenser, the key being to relocate the water jet, (which condenses the steam and creates the vacuum in the Newcomen engine) inside an additional cylindrical vessel of smaller size enclosed in a water bath; the still-warm condensate is then evacuated into a hot well by means of a suction pump allowing the preheated water to be returned to the boiler. This greatly increases thermal efficiency by ensuring that the main cylinder can be kept hot at all times, unlike in the Newcomen engines where the condensing water spray cooled the cylinder at each stroke. Watt also closes off the top of the cylinder causing steam at a pressure marginally above that of the atmosphere to act on top of the piston against the vacuum created beneath it (in this sense Watt might be said to have "invented" the steam engine). In view of this, the engine is no longer "atmospheric" and less susceptible to variations in atmospheric pressure. 
  *[[1765]]: [[Matthew Boulton]] opens the [[Soho Manufactory]] engineering works in [[Handsworth, West Midlands|Handsworth]].
  *[[1769]]: [[James Watt]] is granted a patent on his improved design. The increase in efficiency is enough for Watt and his partner [[Matthew Boulton]] to license the design based on the savings in coal per year, as opposed to a fixed fee. In the past this development has erroneously been characterised as marking the start of the [[Industrial Revolution]]<ref>Hulse, David K., The development of rotary motion by steam power (TEE Publishing Ltd., Leamington, UK., 2001) ISBN 1 85761 119 5</ref>.  
  *[[1775]]: Watt and Boulton enter into a formal partnership.  Watt's patent is extended by Act of Parliament for 25 years until 1800.
  *[[1776]]: First commercial Boulton and Watt engine built. At this stage and until 1795 B&W only provided designs, plans, the most complicated engine parts and support with on-site erection.
  *[[1781]]: [[Jonathan Hornblower]] patents a two-cylinder "compound" engine, in which the steam pushes on one piston (as opposed to pulling via vacuum as in previous designs), and when it reaches the end of its stroke is transferred into a second cylinder that exhausts into a condenser as "normal". Hornblower's design is more efficient than Watt's single-acting designs, but similar enough to his double-acting system that [[Boulton and Watt]] are able to have the patent overturned by the courts in 1799. 
  *[[1782]]:  First Watt rotative engine, driving a flywheel by means of the sun-and-planet gear (an arrangement of cogs) rather than a crank, thus avoiding [[James Pickard]]'s patent.  Watt secures further patents in this year and 1784.
  *[[1783]]: Watt builds his first "double acting" engine, which admits steam so as to alternately act on one side of the piston then on the other; steam exhausts at each return stroke into a condenser. This change enables use of a flywheel imparting steady rotary motion controlled by a governor, thus making it possible for the engine to drive machinery in cotton mills, breweries and other manufacturing industries.
  *[[1791]]: [[William Bull]] makes a seemingly obvious design change by inverting the steam engine directly above the mine pumps, eliminating the large beam used since Newcomen's designs.  About 10 of his engines are built in Cornwall.
  *[[1799]]: [[Richard Trevithick]] builds his first high-pressure engine at [[Dolcoath mine|Dolcoath tin mine]] in Cornwall.
  *[[1800]]: Watt's patent expires.  By this time about 450 Watt engines and over 1500 Newcomen engines have been built in the UK.

======Improving power======
  *[[1804]]: [[Arthur Woolf]] re-introduces Hornblower's double-cylinder designs now that Watt's patents have expired. He goes on to build a number of examples with up to nine cylinders as boiler pressures increase through better manufacturing and materials.
  *[[1801]] [[Richard Trevithick]] builds and runs Camborne road engine.
  *[[1804]] [[Richard Trevithick]] builds and runs single-cylinder flywheel locomotive on the 9-mile Pen-y-Darran tramway. due to plate breakages the engine is installed at Dowlais for stationary use<ref>Young, Robert: “Timothy Hackworth and the Locomotive”; the Book guild Ltd, Lewes, U.K. (2000) (reprint of 1923 ed.)</ref>.
  *[[1804]] John Steel builds locomotive to Trevithick's model at Gateshead for Mr Smith. This is demonstrated to [[Blackett of Wylam|Christopher Blackett]] who refuses it for reasons of excess weight.
  *[[1808]] [[Blackett of Wylam|Christopher Blackett]] relays track at [[Wylam]] Colliery
  *[[1811]] Blackett employs [[Thomas Waters]] to build a new flywheel locomotive.
  *[[1811]] Blackett instructs [[Timothy Hackworth]] to build hand-cranked chassis to prove feasibility of smooth rail for traction.
  *[[1811]] Second Wylam locomotive built by Blackett's development team consisting of [[Timothy Hackworth]], [[William Hedley]], and [[Jonathan Foster]].
  *[[1812]] [[Blenkinsop]] develops rack railway system in collaboration with [[Matthew Murray]] of Leeds Round Foundry - single-flue boiler; vertical cylinders sunk into boiler.
  *[[1813]] Third Wylam locomotive built, with 8 wheels to spread axle load.
  *[[1815]] [[George Stephenson]] builds ''[[jernbaner:Blücher (lokomotiv)|Blücher]]'' - similar to Blenkinsop model.
  *[[1825]] [[Robert Stephenson and Company|Robert Stephenson & Co]] build ''[[Locomotion No 1|Locomotion]]'' for [[Stockton and Darlington Railway]].
  *[[1827]] [[Timothy Hackworth]] builds highly efficient [[Timothy Hackworth#The Royal George|''Royal George'']] with centrally-placed [[blastpipe]] in the chimney for Stockton and Darlington Railway.
  *[[1829]] [[Robert Stephenson and Company|Robert Stephenson & Co]] successfully competes at [[Rainhill Trials]] against Hackworth's ''[[Sans Pareil]]'' and [[Braithwaite and Ericsson's]] ''[[Novelty (locomotive)|Novelty]]''.
  * [[1830]] ''Stephensonian'' locomotive configuration appears with Stephenson's ''Planet'' type along with [[Edward Bury]]'s ''Liverpool'' - horizontal cylinders placed beneath smokebox; drive to rear crank - bar frames.
  *[[1849]]: [[George Henry Corliss]] develops and markets the [[Corliss steam engine|Corliss-type steam engine]], a four-valve counterflow engine with separate steam admission and exhaust valves.  Drop-valve mechanisms provide sharp cutoff of steam during admission stroke. The efficiency of Corliss engines greatly exceeds other engines of the period, and they are rapidly adopted in stationary service throughout industry.
  *[[1854]]: John Ramsbottom publishes a report on his use of oversized steel piston rings which maintain a seal by outward spring tension on the cylinder wall. This allows much better sealing (compared to earlier cotton seals) which leads to significantly higher system pressures before "blow-by" is experienced.
  *[[1865]]: [[Auguste Mouchout]] invents the first device to convert [[solar energy]] into mechanical steam power, using a cauldron filled with water enclosed in glass, which would be put in the sun to boil the water.
  *[[1867]]: [[Stephen Wilcox]] and his partner [[George H. Babcock]] patent the "Babcock & Wilcox Non-Explosive Boiler", which uses water inside clusters of tubing to generate steam, typically with higher pressures and more efficiently than the typical "firetube" boilers of that time. [[Babcock and Wilcox]] -type boiler designs become popular in new installations.
  *[[1897]]: [[Charles Algernon Parsons]] patented a [[steam turbine]], which was used to power a ship. The turbine works like a multi-cylinder steam engine, but with any number of "cylinders" in series, built of simple bladed wheels. The efficiency of large steam turbines is considerably better than the best compound engines, while also being much simpler, more reliable, smaller and lighter all at the same time. Steam turbines have replaced piston engines for power generation almost universally since then.
  *[[1897]]: Stanley Brothers begin selling lightweight steam cars, over 200 being made.
  *[[1899]]: The Locomobile Company begins manufacture of the first production steam-powered cars, after purchasing manufacturing rights from the Stanley Brothers.
  *[[1902]]: The Stanley Motor Carriage Company begins manufacture of the [[Stanley Steamer]], the most popular production steam-powered car.
  *[[1903]]: [[Commonwealth Edison]] Fisk Street Station opens in [[Chicago]], using 32 [[Babcock and Wilcox]] boilers driving several [[General Electric|GE]] Curtis turbines, at 5000 and 9000 kilowatts each, the largest turbine-generators in the world at that time.  Almost all electric power generation, from the time of the Fisk Station to the present, is based on steam driven turbine-generators.
  *[[1913]]: [[Nikola Tesla]] patents a [[Tesla turbine|bladeless steam turbine]] that utilizes the ''[[Boundary layer|boundary layer effect]]''. This design has never been used commercially due to its low efficiency{{Fact|date=February 2008}}.
  *[[1923]]: [[Alan Arnold Griffith]] publishes ''An Aerodynamic Theory of Turbine Design'', describing a way to dramatically improve the efficiency of all turbines. In addition to making newer power plants more economical, it also provides enough efficiency to build a [[jet engine]].

=====External links=====
  *[http://www.history.rochester.edu/steam/thurston/1878/Chapter1.html The Growth of the Steam Engine]

  *[http://devon.freepgs.com/2006/08/no-dark-satanic-mills.php Alternative timeline: If electric generators & motors had preceded steam]